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  • 1.
    Abali, Bilen Emek
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics. Univ Nat Resources & Life Sci, Christian Doppler Lab LiCRoFast, Peter Jordan Str 82, A-1190 Vienna, Austria.
    Zecchini, Michele
    Univ Nat Resources & Life Sci, Christian Doppler Lab LiCRoFast, Peter Jordan Str 82, A-1190 Vienna, Austria.
    Daissè, Gilda
    Univ Nat Resources & Life Sci, Christian Doppler Lab LiCRoFast, Peter Jordan Str 82, A-1190 Vienna, Austria.
    Czabany, Ivana
    BOKU Univ Nat Resources & Life Sci, Dept Mat Sci & Proc Engn, Inst Wood Technol & Renewable Mat, Konrad Lorenz Str 24, A-3430 Tulln, Austria.
    Gindl-Altmutter, Wolfgang
    BOKU Univ Nat Resources & Life Sci, Dept Mat Sci & Proc Engn, Inst Wood Technol & Renewable Mat, Konrad Lorenz Str 24, A-3430 Tulln, Austria.
    Wan-Wendner, Roman
    Univ Nat Resources & Life Sci, Christian Doppler Lab LiCRoFast, Peter Jordan Str 82, A-1190 Vienna, Austria; Univ Ghent, Dept Struct Engn & Bldg Mat, Magnel Lab, Technol Pk Zwijnaarde 60, B-9052 Ghent, Belgium.
    Cure Kinetics and Inverse Analysis of Epoxy-Amine Based Adhesive Used for Fastening Systems2021In: Materials, E-ISSN 1996-1944, Vol. 14, no 14, article id 3853Article in journal (Refereed)
    Abstract [en]

    Thermosetting polymers are used in building materials, for example adhesives in fastening systems. They harden in environmental conditions with a daily temperature depending on the season and location. This curing process takes hours or even days effected by the relatively low ambient temperature necessary for a fast and complete curing. As material properties depend on the degree of cure, its accurate estimation is of paramount interest and the main objective in this work. Thus, we develop an approach for modeling the curing process for epoxy based thermosetting polymers. Specifically, we perform experiments and demonstrate an inverse analysis for determining parameters in the curing model. By using calorimetry measurements and implementing an inverse analysis algorithm by using open-source packages, we obtain 10 material parameters describing the curing process. We present the methodology for two commercial, epoxy based products, where a statistical analysis provides independence of material parameters leading to the conclusion that the material equation is adequately describing the material response.

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  • 2.
    Abbasi, Mazhar Ali
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hussain Ibupoto, Zafar
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hussain, Mushtaque
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Pozina, Galia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Decoration of ZnO nanorods with coral reefs like NiO nanostructures by the hydrothermal growth method and their luminescence study2014In: Materials, E-ISSN 1996-1944, Vol. 7, no 1, p. 430-440Article in journal (Refereed)
    Abstract [en]

    Composite nanostructures of coral reefs like p-type NiO on n-type ZnO nanorods have been decorate on fluorine-doped tin oxide glass substrates by the hydrothermal growth. Structural characterization was performed by field emission scanning electron microscopy,  high-resolution transmission electron microscopy and X-ray diffraction techniques. This investigation has shown that the adopted synthesis has led to high crystalline quality nanostructures. Morphological study shows that the coral reefs like nanostructures are densely packed on the ZnO nanorods. Cathodoluminescence (CL) spectra for the synthesized composite nanostructures were dominated by a near band gap emission at 380 nm and by a broad interstitial defect related luminescence centered at ~630 nm. Spatially resolved CL images reveal that the luminescence originates mainly from the ZnO nanorods.

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  • 3.
    Abdel-Halim, Maha
    et al.
    Malmö University, Faculty of Odontology (OD).
    Issa, Dalia
    Malmö University, Faculty of Odontology (OD).
    Chrcanovic, Bruno
    Malmö University, Faculty of Odontology (OD).
    The Impact of Dental Implant Length on Failure Rates: A Systematic Review and Meta-Analysis2021In: Materials, E-ISSN 1996-1944, Vol. 14, no 14, article id 3972Article, review/survey (Refereed)
    Abstract [en]

    The present review aimed to evaluate the impact of implant length on failure rates between short (<10 mm) and long (>= 10 mm) dental implants. An electronic search was undertaken in three databases, as well as a manual search of journals. Implant failure was the outcome evaluated. Meta-analysis was performed in addition to a meta-regression in order to verify how the risk ratio (RR) was associated with the follow-up time. The review included 353 publications. Altogether, there were 25,490 short and 159,435 long implants. Pairwise meta-analysis showed that short implants had a higher failure risk than long implants (RR 2.437, p < 0.001). There was a decrease in the probability of implant failure with longer implants when implants of different length groups were compared. A sensitivity analysis, which plotted together only studies with follow-up times of 7 years or less, resulted in an estimated increase of 0.6 in RR for every additional month of follow-up. In conclusion, short implants showed a 2.5 times higher risk of failure than long implants. Implant failure is multifactorial, and the implant length is only one of the many factors contributing to the loss of an implant. A good treatment plan and the patient's general health should be taken into account when planning for an implant treatment.

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  • 4.
    Abrikosov, Igor
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Knutsson, Axel
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Alling, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Tasnádi, Ferenc
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Lind, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Phase Stability and Elasticity of TiAlN2011In: Materials, E-ISSN 1996-1944, Vol. 4, no 9, p. 1599-1618Article in journal (Refereed)
    Abstract [en]

    We review results of recent combined theoretical and experimental studies of Ti1−xAlxN, an archetypical alloy system material for hard-coating applications. Theoretical simulations of lattice parameters, mixing enthalpies, and elastic properties are presented. Calculated phase diagrams at ambient pressure, as well as at pressure of 10 GPa, show a wide miscibility gap and broad region of compositions and temperatures where the spinodal decomposition takes place. The strong dependence of the elastic properties and sound wave anisotropy on the Al-content offers detailed understanding of the spinodal decomposition and age hardening in Ti1−xAlxN alloy films and multilayers. TiAlN/TiN multilayers can further improve the hardness and thermal stability compared to TiAlN since they offer means to influence the kinetics of the favorable spinodal decomposition and suppress the detrimental transformation to w-AlN. Here, we show that a 100 degree improvement in terms of w-AlN suppression can be achieved, which is of importance when the coating is used as a protective coating on metal cutting inserts.

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  • 5.
    Adegoke, Olutayo
    et al.
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Andersson, Joel
    University West, Department of Engineering Science, Division of Welding Technology.
    Brodin, Håkan
    Materials Technology Additive Manufacturing Product Development-Industrial Gas Turbines, Siemens Industrial Turbomachinery, Finspång, SE-612 83, Sweden.
    Pederson, Robert
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Influence of laser powder bed fusion process parameters on voids, cracks, and microhardness of nickel-based superalloy alloy 247LC2020In: Materials, E-ISSN 1996-1944, Vol. 13, no 17, article id 3770Article in journal (Refereed)
    Abstract [en]

    The manufacturing of parts from nickel-based superalloy Alloy 247LC by laser powder bed fusion (L-PBF) is challenging, primarily owing to the alloy’s susceptibility to cracks. Apart from the cracks, voids created during the L-PBF process should also be minimized to produce dense parts. In this study, samples of Alloy 247LC were manufactured by L-PBF, several of which could be produced with voids and crack density close to zero. A statistical design of experiments was used to evaluate the influence of the process parameters, namely laser power, scanning speed, and hatch distance (inherent to the volumetric energy density) on void formation, crack density, and microhardness of the samples. The window of process parameters, in which minimum voids and/or cracks were present, was predicted. It was shown that the void content increased steeply at a volumetric energy density threshold below 81 J/mm3. The crack density, on the other hand, increased steeply at a volumetric energy density threshold above 163 J/mm3. The microhardness displayed a relatively low value in three samples which displayed the lowest volumetric energy density and highest void content. It was also observed that two samples, which displayed the highest volumetric energy density and crack density, demonstrated a relatively high microhardness; which could be a vital evidence in future investigations to determine the fundamental mechanism of cracking. The laser power was concluded to be the strongest and statistically most significant process parameter that influenced void formation and microhardness. The interaction of laser power and hatch distance was the strongest and most significant factor that influenced the crack density. © 2020 by the authors.

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  • 6.
    Ahmad, Shargeel
    et al.
    Dalian Univ Technol, Inst Artificial Photosynthesis, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Liu, Jinxuan
    Dalian Univ Technol, Inst Artificial Photosynthesis, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Ji, Wei
    Dalian Univ Technol, Inst Artificial Photosynthesis, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry. Dalian Univ Technol, Inst Artificial Photosynthesis, State Key Lab Fine Chem, Dalian 116024, Peoples R China.;KTH Royal Inst Technol, Sch Chem Sci & Engn, Dept Chem, S-10044 Stockholm, Sweden..
    Metal-Organic Framework Thin Film-Based Dye Sensitized Solar Cells with Enhanced Photocurrent2018In: Materials, E-ISSN 1996-1944, Vol. 11, no 10, article id 1868Article in journal (Refereed)
    Abstract [en]

    Metal-organic framework thin film-based dye sensitized solar cell is fabricated with highly oriented, crystalline, and porous Zn-perylene metal-organic framework (MOF) thin film (SURMOF) which is integrated with Bodipy embedded in poly(methyl methacrylate). It has been demonstrated that the photocurrent can be enhanced by a factor of 5 relative to Zn-perylene MOF thin film due to triplet-triplet annihilation up-conversion between the Bodipy/PMMA sensitizer and the Zn-perylene MOF thin film acceptor using Co(bpy)(3)(2+/3+) as redox mediator.

  • 7.
    Ahmed Waqas, Hafiz
    et al.
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi 23640, Pakistan.
    Bahrami, Alireza
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Sahil, Mehran
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi 23640, Pakistan.
    Poshad Khan, Adil
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi 23640, Pakistan.
    Ejaz, Ali
    National University of Science and Technology, Risalpur 23200, Pakistan.
    Shafique, Taimoor
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi 23640, Pakistan.
    Tariq, Zain
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi 23640, Pakistan.
    Ahmad, Sajeel
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi 23640, Pakistan.
    Onuralp Özkılıç, Yasin
    Necmettin Erbakan University, Konya, Turkey.
    Performance Prediction of Hybrid Bamboo-Reinforced Concrete Beams Using Gene Expression Programming for Sustainable Construction2023In: Materials, E-ISSN 1996-1944, Vol. 16, no 20, article id 6788Article in journal (Refereed)
    Abstract [en]

    The building and construction industry’s demand for steel reinforcement bars has increased with the rapid growth and development in the world. However, steel production contributes to harmful waste and emissions that cause environmental pollution and climate change-related problems. In light of sustainable construction practices, bamboo, a readily accessible and ecofriendly building material, is suggested as a viable replacement for steel rebars. Its cost-effectiveness, environmental sustainability, and considerable tensile strength make it a promising option. In this research, hybrid beams underwent analysis through the use of thoroughly validated finite element models (FEMs), wherein the replacement of steel rebars with bamboo was explored as an alternative reinforcement material. The standard-size beams were subjected to three-point loading using FEMs to study parameters such as the load–deflection response, energy absorption, maximum capacity, and failure patterns. Then, gene expression programming was integrated to aid in developing a more straightforward equation for predicting the flexural strength of bamboo-reinforced concrete beams. The results of this study support the conclusion that the replacement of a portion of flexural steel with bamboo in reinforced concrete beams does not have a detrimental impact on the overall load-bearing capacity and energy absorption of the structure. Furthermore, it may offer a cost-effective and feasible alternative. 

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  • 8.
    Ajpi, Cesario
    et al.
    Universidad Mayor de San Andres, Bolivia; KTH Royal Institute of Technology, Sweden.
    Leiva, Naviana
    Universidad Mayor de San Andres, Bolivia.
    Vargas, Max
    Universidad Mayor de San Andres, Bolivia.
    Lundblad, Anders Olof
    RISE Research Institutes of Sweden, Safety and Transport, Electrification and Reliability.
    Lindbergh, Göran
    KTH Royal Institute of Technology, Sweden.
    Cabrera, Saul
    Universidad Mayor de San Andres, Bolivia.
    Synthesis and characterization of LiFePO4-PANI hybrid material as cathode for lithium-ion batteries2020In: Materials, E-ISSN 1996-1944, Vol. 13, no 12Article in journal (Refereed)
    Abstract [en]

    This work focuses on the synthesis of LiFePO4-PANI hybrid materials and studies their electrochem. properties (capacity, cyclability and rate capability) for use in lithium ion batteries. PANI synthesis and optimization was carried out by chem. oxidation (self-assembly process), using ammonium persulfate (APS) and H3PO4, obtaining a material with a high degree of crystallinity. For the synthesis of the LiFePO4-PANI hybrid, a thermal treatment of LiFePO4 particles was carried out in a furnace with polyaniline (PANI) and lithium acetate (AcOLi)-coated particles, using Ar/H2 atm. The pristine and synthesized powders were characterized by XRD, SEM, IR and TGA. The electrochem. characterizations were carried out by using CV, EIS and galvanostatic methods, obtaining a capacity of 95 mAhg-1 for PANI, 120 mAhg-1 for LiFePO4 and 145 mAhg-1 for LiFePO4-PANI, at a charge/discharge rate of 0.1 C. At a charge/discharge rate of 2 C, the capacities were 70 mAhg-1 for LiFePO4 and 100 mAhg-1 for LiFePO4-PANI, showing that the PANI also had a favorable effect on the rate capability.

  • 9.
    Ajpi Condori, Cesario
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry. UMSA Univ Mayor San Andres, IIQ Chem Res Inst, Dept Inorgan Chem & Mat Sci Adv Mat, La Paz 303, Bolivia..
    Leiva, Naviana
    UMSA Univ Mayor San Andres, IIQ Chem Res Inst, Dept Inorgan Chem & Mat Sci Adv Mat, La Paz 303, Bolivia..
    Vargas, Max
    UMSA Univ Mayor San Andres, IIQ Chem Res Inst, Dept Inorgan Chem & Mat Sci Adv Mat, La Paz 303, Bolivia..
    Lundblad, Anders
    RISE, Res Inst, Div Safety & Transport Elect, SE-50462 Borås, Sweden..
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Cabrera, Saul
    UMSA Univ Mayor San Andres, IIQ Chem Res Inst, Dept Inorgan Chem & Mat Sci Adv Mat, La Paz 303, Bolivia..
    Synthesis and Characterization of LiFePO4-PANI Hybrid Material as Cathode for Lithium-Ion Batteries2020In: Materials, E-ISSN 1996-1944, Vol. 13, no 12, article id 2834Article in journal (Refereed)
    Abstract [en]

    This work focuses on the synthesis of LiFePO4-PANI hybrid materials and studies their electrochemical properties (capacity, cyclability and rate capability) for use in lithium ion batteries. PANI synthesis and optimization was carried out by chemical oxidation (self-assembly process), using ammonium persulfate (APS) and H3PO4, obtaining a material with a high degree of crystallinity. For the synthesis of the LiFePO4-PANI hybrid, a thermal treatment of LiFePO(4)particles was carried out in a furnace with polyaniline (PANI) and lithium acetate (AcOLi)-coated particles, using Ar/H(2)atmosphere. The pristine and synthetized powders were characterized by XRD, SEM, IR and TGA. The electrochemical characterizations were carried out by using CV, EIS and galvanostatic methods, obtaining a capacity of 95 mAhg(-1)for PANI, 120 mAhg(-1)for LiFePO(4)and 145 mAhg(-1)for LiFePO4-PANI, at a charge/discharge rate of 0.1 C. At a charge/discharge rate of 2 C, the capacities were 70 mAhg(-1)for LiFePO(4)and 100 mAhg(-1)for LiFePO4-PANI, showing that the PANI also had a favorable effect on the rate capability.

  • 10.
    Akinwekomi, Akeem
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Department of Metallurgical and Materials Engineering, Federal University of Technology Akure, Akure 340252, Ondo State, Nigeria.
    Akhtar, Farid
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Microstructural, Mechanical, and Electrochemical Characterization of CrMoNbTiZr High-Entropy Alloy for Biomedical Application2023In: Materials, E-ISSN 1996-1944, Vol. 16, no 15, article id 5320Article in journal (Refereed)
    Abstract [en]

    High-entropy alloys (HEA) with superior biocompatibility, high pitting resistance, minimal debris accumulation, and reduced release of metallic ions into surrounding tissues are potential replacements for traditional metallic bio-implants. A novel equiatomic HEA based on biocompatible metals, CrMoNbTiZr, was consolidated by spark plasma sintering (SPS). The relative sintered density of the alloy was about 97% of the theoretical density, indicating the suitability of the SPS technique to produce relatively dense material. The microstructure of the sintered HEA consisted of a BCC matrix and Laves phase, corresponding to the prediction of the thermodynamic CALPHAD simulation. The HEA exhibited a global Vickers microhardness of 531.5 ± 99.7 HV, while the individual BCC and Laves phases had hardness values of 364.6 ± 99.4 and 641.8 ± 63.0 HV, respectively. Its ultimate compressive and compressive yield strengths were 1235.7 ± 42.8 MPa and 1110.8 ± 78.6 MPa, respectively. The elasticity modulus of 34.9 ± 2.9 GPa of the HEA alloy was well within the range of cortical bone and significantly lower than the values reported for commonly used biomaterials made from Ti-based and Cr–Co-based alloys. In addition, the alloy exhibited good resistance to bio-corrosion in PBS and Hanks solutions. The CrMoNbTiZr HEA exhibited an average COF of 0.43 ± 0.06, characterized mainly by abrasive and adhesive wear mechanisms. The CrMoNbTiZr alloy’s mechanical, bio-corrosion, and wear resistance properties developed in this study showed a good propensity for application as a biomaterial.

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  • 11.
    Al Ansari, Yasmin
    et al.
    Malmö University, Faculty of Odontology (OD).
    Shahwan, Halime
    Malmö University, Faculty of Odontology (OD).
    Chrcanovic, Bruno Ramos
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Diabetes Mellitus and Dental Implants: A Systematic Review and Meta-Analysis2022In: Materials, E-ISSN 1996-1944, Vol. 15, no 9, article id 3227Article, review/survey (Refereed)
    Abstract [en]

    The present review aimed to evaluate the impact of diabetes mellitus on dental implant failure rates and marginal bone loss (MBL). An electronic search was undertaken in three databases, plus a manual search of journals. Meta-analyses were performed as well as meta-regressions in order to verify how the odds ratio (OR) and MBL were associated with follow-up time. The review included 89 publications. Altogether, there were 5510 and 62,780 implants placed in diabetic and non-diabetic patients, respectively. Pairwise meta-analysis showed that implants in diabetic patients had a higher failure risk in comparison to non-diabetic patients (OR 1.777, p < 0.001). Implant failures were more likely to occur in type 1 diabetes patients than in type 2 (OR 4.477, p = 0.032). The difference in implant failure between the groups was statistically significant in the maxilla but not in the mandible. The MBL mean difference (MD) between the groups was 0.776 mm (p = 0.027), with an estimated increase of 0.032 mm in the MBL MD between groups for every additional month of follow-up (p < 0.001). There was an estimated decrease of 0.007 in OR for every additional month of follow-up (p = 0.048). In conclusion, implants in diabetic patients showed a 77.7% higher risk of failure than in non-diabetic patients.

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  • 12.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Linnaeus University, Linnaeus Knowledge Environments, Advanced Materials.
    Elastic Properties and Hardness of Mixed Alkaline Earth Silicate Oxynitride Glasses2022In: Materials, E-ISSN 1996-1944, Vol. 15, no 14, article id 5022Article in journal (Refereed)
    Abstract [en]

    The incorporation of nitrogen as a second anion species into oxide glasses offers unique opportunities for modifying glass properties via changes in glass polymerization and structure. In this work, the compositional dependence of elastic properties and the nanoindentation hardness of mixed alkaline-earth silicate oxynitride glasses containing a high amount of nitrogen (>15 at.%, c.a. 35 e/o) were investigated. Three series of silicon oxynitride glass compositions AE-Ca-Si-O-N glasses (where AE = Mg, Sr, and Ba) having varying amounts of modifiers were prepared using a new glass synthesis route, in which a precursor powder of metal hydrides was used. The obtained glasses contained high amounts of N (19 at.%, c.a. 43 e/o) and modifier cations (26 at.%, c.a. 39 e/o). Mg-Ca-Si-O-N glasses had high values of nanohardness (12-16 GPa), along with a reduced elastic modulus (130-153 GPa) and Young's modulus (127-146 GPa), in comparison with the Sr-Ca- and Ba-Ca-bearing oxynitride glasses. Both the elastic modulus and the nanohardness of AE-Ca-Si-O-N glasses decreased with an increase in the atomic number of the AE element. These property changes followed a linear dependence on the effective cation field strength (ECFS) of the alkaline earth (AE) modifier, according to their valences and ionic radii. No mixed alkaline-earth effect was observed in the current investigation, indicating that the properties were more dictated by the nitrogen content.

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  • 13.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Linnaeus University, Linnaeus Knowledge Environments, Advanced Materials.
    Impact of the Atomic Packing Density on the Properties of Nitrogen-Rich Calcium Silicate Oxynitride Glasses2022In: Materials, E-ISSN 1996-1944, Vol. 15, no 17, article id 6054Article in journal (Refereed)
    Abstract [en]

    In this work, the impact of the atomic packing density/fractional glass compactness of Ca-Si-O-N glasses on glass transition and crystallization temperatures, glass density, microhardness, molar volume, and refractive index were examined. It was found that the atomic packing density increased with increasing the nitrogen content and decreased with increasing the Ca content in the glass network. Furthermore, density, glass transition and crystallization temperatures, and refractive index, increased with an increasing atomic packing density of the glass, while molar volume increased with decreasing atomic packing density values. The change in hardness with atomic packing density is less clear and suggests that the atomic packing density does not solely control the underlying deformation mechanism. There is indeed competition between densification (favored at low packing density values) and isochoric shear (at larger packing density). Despite that, the effects of nitrogen as a network former and Ca as a modifier are significantly independent. The obtained results indicate that the atomic packing density of the prepared samples linearly depends on many mechanical and optical properties, suggesting that the glass network and cross-linking are proportional to the ionic radius of the Ca and the nitrogen content, respectively.

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  • 14.
    Aliramaji, Shamsa
    et al.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Keuter, Philipp
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Neuss, Deborah
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Hans, Marcus
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Depla, Diederik
    Univ Ghent, Dept Solid State Sci, Krijgslaan 281 S1, B-9000 Ghent, Belgium..
    Schneider, Jochen M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Effect of Growth Temperature and Atmosphere Exposure Time on Impurity Incorporation in Sputtered Mg, Al, and Ca Thin Films2023In: Materials, E-ISSN 1996-1944, Vol. 16, no 1, article id 414Article in journal (Refereed)
    Abstract [en]

    Impurities can be incorporated during thin film deposition, but also can originate from atmosphere exposure. As impurities can strongly affect the composition-structure-property relations in magnetron sputter deposited thin films, it is important to distinguish between both incorporation channels. Therefore, the impurity incorporation by atmosphere exposure into sputtered Mg, Al, and Ca thin films is systematically studied by a variation of the deposition temperatures and atmosphere exposure times. Deposition temperature variation results in morphological modifications explained by considering surface and bulk diffusion as well as grain boundary motion and evaporation. The film morphologies exhibiting the lowest oxygen concentrations, as measured by energy dispersive X-ray spectroscopy, are obtained at a homologous temperature of 0.4 for both Mg and Al thin films. For Ca, preventing atmosphere exposure is essential to hinder impurity incorporation: By comparing the impurity concentration in Al-capped and uncapped thin films, it is demonstrated that Ca thin films are locally protected by Al-capping, while Mg (and Al) form native passivation layers. Furthermore, it can be learned that the capping (or self-passivation) efficiency in terms of hindering further oxidation of the films in atmosphere is strongly dependent on the underlying morphology, which in turn is defined by the growth temperature.

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  • 15.
    Al-Maqdasi, Zainab
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Gong, Guan
    Rise Sicomp AB, Fibervägen 2, SE-941 26 Öjebyn, Sweden.
    Nyström, Birgitha
    Podcomp AB, Skylvägen 1, SE-943 33 Öjebyn, Sweden.
    Emami, Nazanin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Joffe, Roberts
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Characterization of Wood and Graphene Nanoplatelets (GNPs) Reinforced Polymer Composites2020In: Materials, E-ISSN 1996-1944, Vol. 13, no 9, article id 2089Article in journal (Refereed)
    Abstract [en]

    This paper investigates the utilization of commercial masterbatches of graphene nanoplatelets to improve the properties of neat polymer and wood fiber composites manufactured by conventional processing methods. The effect of aspect ratio of the graphene platelets (represented by the different number of layers in the nanoplatelet) on the properties of high-density polyethylene (HDPE) is discussed. The composites were characterized for their mechanical properties (tensile, flexural, impact) and physical characteristics (morphology, crystallization, and thermal stability). The effect of the addition of nanoplatelets on the thermal conductivity and diffusivity of the reinforced polymer with different contents of reinforcement was also investigated. In general, the mechanical performance of the polymer was enhanced at the presence of either of the reinforcements (graphene or wood fiber). The improvement in mechanical properties of the nanocomposite was notable considering that no compatibilizer was used in the manufacturing. The use of a masterbatch can promote utilization of nano-modified polymer composites on an industrial scale without modification of the currently employed processing methods and facilities.

  • 16.
    Al-Maqdasi, Zainab
    et al.
    Luleå University of Technology, Sweden.
    Gong, Guan
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Nyström, Birgitha
    Podcomp AB, Sweden.
    Emami, Nazanin
    Luleå University of Technology, Sweden.
    Joffe, Roberts
    Luleå University of Technology, Sweden.
    Characterization of Wood and Graphene Nanoplatelets (GNPs) Reinforced Polymer Composites.2020In: Materials, E-ISSN 1996-1944, Vol. 13, no 9, article id E2089Article in journal (Refereed)
    Abstract [en]

    This paper investigates the utilization of commercial masterbatches of graphene nanoplatelets to improve the properties of neat polymer and wood fiber composites manufactured by conventional processing methods. The effect of aspect ratio of the graphene platelets (represented by the different number of layers in the nanoplatelet) on the properties of high-density polyethylene (HDPE) is discussed. The composites were characterized for their mechanical properties (tensile, flexural, impact) and physical characteristics (morphology, crystallization, and thermal stability). The effect of the addition of nanoplatelets on the thermal conductivity and diffusivity of the reinforced polymer with different contents of reinforcement was also investigated. In general, the mechanical performance of the polymer was enhanced at the presence of either of the reinforcements (graphene or wood fiber). The improvement in mechanical properties of the nanocomposite was notable considering that no compatibilizer was used in the manufacturing. The use of a masterbatch can promote utilization of nano-modified polymer composites on an industrial scale without modification of the currently employed processing methods and facilities.

  • 17.
    Al-Maqdasi, Zainab
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Joffe, Roberts
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Ouarga, Ayoub
    High Throughput Multidisciplinary Research Laboratory, Mohammed VI Polytechnic University (UM6P), Lot 660—Hay Moulay Rachid, 43150 Benguerir, Morocco.
    Emami, Nazanin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Chouhan, Shailesh Singh
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Landström, Anton
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Hajlane, Abdelghani
    Laboratory of Crystallography and Materials Sciences, National Graduate School of Engineering of Caen, 6 Boulevard Maréchal Juin, 14000 Caen, France.
    Conductive Regenerated Cellulose Fibers for Multi-Functional Composites: Mechanical and Structural Investigation2021In: Materials, E-ISSN 1996-1944, Vol. 14, no 7, article id 1746Article in journal (Refereed)
    Abstract [en]

    Regenerated cellulose fibers coated with copper via electroless plating process are investigated for their mechanical properties, molecular structure changes, and suitability for use in sensing applications. Mechanical properties are evaluated in terms of tensile stiffness and strength of fiber tows before, during and after the plating process. The effect of the treatment on the molecular structure of fibers is investigated by measuring their thermal stability with differential scanning calorimetry and obtaining Raman spectra of fibers at different stages of the treatment. Results show that the last stage in the electroless process (the plating step) is the most detrimental, causing changes in fibers’ properties. Fibers seem to lose their structural integrity and develop surface defects that result in a substantial loss in their mechanical strength. However, repeating the process more than once or elongating the residence time in the plating bath does not show a further negative effect on the strength but contributes to the increase in the copper coating thickness, and, subsequently, the final stiffness of the tows. Monitoring the changes in resistance values with applied strain on a model composite made of these conductive tows show an excellent correlation between the increase in strain and increase in electrical resistance. These results indicate that these fibers show potential when combined with conventional composites of glass or carbon fibers as structure monitoring devices without largely affecting their mechanical performance.

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  • 18.
    Almusaed, Amjad
    et al.
    Jönköping University, School of Engineering, JTH, Civil Engineering and Lighting Science.
    Yitmen, Ibrahim
    Jönköping University, School of Engineering, JTH, Civil Engineering and Lighting Science.
    Almsaad, A.
    Karlstad Univ, Dept Engn & Chem Sci, S-65188 Karlstad, Sweden.
    Akiner, İ.
    Akdeniz Univ, Dept Architecture, TR-07058 Antalya, Turkey.
    Akiner, M. E.
    Akdeniz Univ, Vocat Sch Tech Sci, TR-07058 Antalya, Turkey.
    Coherent investigation on a smart kinetic wooden façade based on material passport concepts and environmental profile inquiry2021In: Materials, E-ISSN 1996-1944, Vol. 14, no 14, article id 3771Article in journal (Refereed)
    Abstract [en]

    Wood is one of the most fully renewable building materials, so wood instead of non-renewable materials produced from organic energy sources significantly reduces the environmental impact. Construction products can be replenished at the end of their working life and their elements and components deconstructed in a closed-loop manner to act as a material for potential construction. Materials passports (MPs) are instruments for incorporating circular economy principles (CEP) into structures. Material passports (MPs) consider all the building’s life cycle (BLC) steps to ensure that it can be reused and transformed several times. The number of reuse times and the operating life of the commodity greatly influence the environmental effects incorporated. For a new generation of buildings, the developing of an elegant kinetic wooden façade has become a necessity. It represents a multidisciplinary region with different climatic, fiscal, constructional materials, equipment, and programs, and ecology-influencing design processes and decisions. Based on an overview of the material’s environmental profile (MEP) and material passport (MP) definition in the design phase, this article attempts to establish and formulate an analytical analysis of the wood selection process used to produce a kinetic façade. The paper will analyze the importance of environmentally sustainable construction and a harmonious architectural environment to reduce harmful human intervention on the environment. It will examine the use of wooden panels on buildings’ façades as one solution to building impact on the environment. It will show the features of the formation of the wooden exterior of the building. It will also examine modern architecture that enters into a dialogue with the environment, giving unique flexibility to adapt a building. The study finds that new buildings can be easily created today. The concept of building materials passport and the environmental selection of the kinetic wooden façade can be incorporated into the building design process. This will improve the economic and environmental impact of the building on human life.

  • 19.
    Almusaed, Amjad
    et al.
    Jönköping University .
    Yitmen, Ibrahim
    Jönköping University .
    Almssad, Asaad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Akiner, Ilknur
    Akdeniz University, TUR.
    Akiner, Muhammed Ernur
    Akdeniz University, TUR.
    Coherent Investigation on a Smart Kinetic Wooden Facade Based on Material Passport Concepts and Environmental Profile Inquiry2021In: Materials, E-ISSN 1996-1944, Vol. 14, no 14, article id 3771Article in journal (Refereed)
    Abstract [en]

    Wood is one of the most fully renewable building materials, so wood instead of non-renewable materials produced from organic energy sources significantly reduces the environmental impact. Construction products can be replenished at the end of their working life and their elements and components deconstructed in a closed-loop manner to act as a material for potential construction. Materials passports (MPs) are instruments for incorporating circular economy principles (CEP) into structures. Material passports (MPs) consider all the building's life cycle (BLC) steps to ensure that it can be reused and transformed several times. The number of reuse times and the operating life of the commodity greatly influence the environmental effects incorporated. For a new generation of buildings, the developing of an elegant kinetic wooden facade has become a necessity. It represents a multidisciplinary region with different climatic, fiscal, constructional materials, equipment, and programs, and ecology-influencing design processes and decisions. Based on an overview of the material's environmental profile (MEP) and material passport (MP) definition in the design phase, this article attempts to establish and formulate an analytical analysis of the wood selection process used to produce a kinetic facade. The paper will analyze the importance of environmentally sustainable construction and a harmonious architectural environment to reduce harmful human intervention on the environment. It will examine the use of wooden panels on buildings' facades as one solution to building impact on the environment. It will show the features of the formation of the wooden exterior of the building. It will also examine modern architecture that enters into a dialogue with the environment, giving unique flexibility to adapt a building. The study finds that new buildings can be easily created today. The concept of building materials passport and the environmental selection of the kinetic wooden facade can be incorporated into the building design process. This will improve the economic and environmental impact of the building on human life.

  • 20.
    Almyras, Georgios
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanoscale engineering. Linköping University, Faculty of Science & Engineering.
    Sangiovanni, Davide Giuseppe
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering. Ruhr Univ Bochum, Germany.
    Sarakinos, Kostas
    Linköping University, Department of Physics, Chemistry and Biology, Nanoscale engineering. Linköping University, Faculty of Science & Engineering.
    Semi-Empirical Force-Field Model For The Ti1-XAlXN (0 ≤ x ≤ 1) System2019In: Materials, E-ISSN 1996-1944, Vol. 12, no 2, article id 215Article in journal (Refereed)
    Abstract [en]

    We present a modified embedded atom method (MEAM) semi-empirical force-field model for the Ti1-xAlxN (0 x 1) alloy system. The MEAM parameters, determined via an adaptive simulated-annealing (ASA) minimization scheme, optimize the models predictions with respect to 0 K equilibrium volumes, elastic constants, cohesive energies, enthalpies of mixing, and point-defect formation energies, for a set of approximate to 40 elemental, binary, and ternary Ti-Al-N structures and configurations. Subsequently, the reliability of the model is thoroughly verified against known finite-temperature thermodynamic and kinetic properties of key binary Ti-N and Al-N phases, as well as properties of Ti1-xAlxN (0 amp;lt; x amp;lt; 1) alloys. The successful outcome of the validation underscores the transferability of our model, opening the way for large-scale molecular dynamics simulations of, e.g., phase evolution, interfacial processes, and mechanical response in Ti-Al-N-based alloys, superlattices, and nanostructures.

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  • 21. Al-Sabahi, Jamal
    et al.
    Bora, Tanujjal
    Al-Abri, Mohammed
    Dutta, Joydeep
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Controlled defects of zinc oxide nanorods for efficient visible light photocatalytic degradation of phenol2016In: Materials, E-ISSN 1996-1944, Vol. 9, no 4, article id 238Article in journal (Refereed)
    Abstract [en]

    Environmental pollution from human and industrial activities has received much attention as it adversely affects human health and bio-diversity. In this work we report efficient visible light photocatalytic degradation of phenol using supported zinc oxide (ZnO) nanorods and explore the role of surface defects in ZnO on the visible light photocatalytic activity. ZnO nanorods were synthesized on glass substrates using a microwave-assisted hydrothermal process, while the surface defect states were controlled by annealing the nanorods at various temperatures and were characterized by photoluminescence and X-ray photoelectron spectroscopy. High performance liquid chromatography (HPLC) was used for the evaluation of phenol photocatalytic degradation. ZnO nanorods with high surface defects exhibited maximum visible light photocatalytic activity, showing 50% degradation of 10 ppm phenol aqueous solution within 2.5 h, with a degradation rate almost four times higher than that of nanorods with lower surface defects. The mineralization process of phenol during degradation was also investigated, and it showed the evolution of different photocatalytic byproducts, such as benzoquinone, catechol, resorcinol and carboxylic acids, at different stages. The results from this study suggest that the presence of surface defects in ZnO nanorods is crucial for its efficient visible light photocatalytic activity, which is otherwise only active in the ultraviolet region.

  • 22.
    Andrearczyk, Tomasz
    et al.
    Polish Acad Sci, Poland.
    Levchenko, Khrystyna
    Polish Acad Sci, Poland;Univ Vienna, Austria.
    Sadowski, Janusz
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering. Polish Acad Sci, Poland.
    Domagala, Jaroslaw Z.
    Polish Acad Sci, Poland.
    Kaleta, Anna
    Polish Acad Sci, Poland.
    Dluzewski, Piotr
    Polish Acad Sci, Poland.
    Wrobel, Jerzy
    Polish Acad Sci, Poland.
    Figielski, Tadeusz
    Polish Acad Sci, Poland.
    Wosinski, Tadeusz
    Polish Acad Sci, Poland.
    Structural Quality and Magnetotransport Properties of Epitaxial Layers of the (Ga,Mn)(Bi,As) Dilute Magnetic Semiconductor2020In: Materials, E-ISSN 1996-1944, Vol. 13, no 23, p. 1-14, article id 5507Article in journal (Refereed)
    Abstract [en]

    Structural analysis of epitaxial layers of the (Ga,Mn)(Bi,As) quaternary dilute magnetic semiconductor (DMS), together with investigations of their magnetotransport properties, has been thoroughly performed. The obtained results are compared with those for the reference (Ga,Mn)As layers, grown under similar conditions, with the aim to reveal an impact of Bi incorporation on the properties of this DMS material. Incorporation of Bi into GaAs strongly enhances the spin-orbit coupling strength in this semiconductor, and the same has been expected for the (Ga,Mn)(Bi,As) alloy. In turn, importantly for specific spintronic applications, strong spin-orbit coupling in ferromagnetic systems opens a possibility of directly controlling the direction of magnetization by the electric current. Our investigations, performed with high-resolution X-ray diffractometry and transmission electron microscopy, demonstrate that the (Ga,Mn)(Bi,As) layers of high structural quality and smooth interfaces can be grown by means of the low-temperature molecular-beam epitaxy method, despite a large difference between the sizes of Bi and As atoms. Depending on the applied buffer layer, the DMS layers can be grown under either compressive or tensile misfit strain, which influences their magnetic properties. It is shown that even small 1% Bi content in the layers strongly affects their magnetoelectric properties, such as the coercive field and anisotropic magnetoresistance.

  • 23.
    Andrearczyk, Tomasz
    et al.
    Polish Acad Sci, Poland.
    Levchenko, Khrystyna
    Polish Acad Sci, Poland;Univ Vienna, Austria.
    Sadowski, Janusz
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering. Polish Acad Sci, Poland.
    Gas, Katarzyna
    Polish Acad Sci, Poland.
    Avdonin, Andrei
    Polish Acad Sci, Poland.
    Wrobel, Jerzy
    Polish Acad Sci, Poland.
    Figielski, Tadeusz
    Polish Acad Sci, Poland.
    Sawicki, Maciej
    Polish Acad Sci, Poland.
    Wosinski, Tadeusz
    Polish Acad Sci, Poland.
    Impact of Bismuth Incorporation into (Ga,Mn)As Dilute Ferromagnetic Semiconductor on Its Magnetic Properties and Magnetoresistance2023In: Materials, E-ISSN 1996-1944, Vol. 16, no 2, article id 788Article in journal (Refereed)
    Abstract [en]

    The impact of bismuth incorporation into the epitaxial layer of a (Ga,Mn)As dilute ferromagnetic semiconductor on its magnetic and electromagnetic properties is studied in very thin layers of quaternary (Ga,Mn)(Bi,As) compound grown on a GaAs substrate under a compressive misfit strain. An addition of a small atomic fraction of 1% Bi atoms, substituting As atoms in the layer, predominantly enhances the spin-orbit coupling strength in its valence band. The presence of bismuth results in a small decrease in the ferromagnetic Curie temperature and a distinct increase in the coercive fields. On the other hand, the Bi incorporation into the layer strongly enhances the magnitude of negative magnetoresistance without affecting the hole concentration in the layer. The negative magnetoresistance is interpreted in terms of the suppression of weak localization in a magnetic field. Application of the weak-localization theory for two-dimensional ferromagnets by Dugaev et al. to the experimental magnetoresistance results indicates that the decrease in spin-orbit scattering length accounts for the enhanced magnetoresistance in (Ga,Mn)(Bi,As).

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  • 24.
    Andrearczyk, Tomasz
    et al.
    Polish Acad Sci, Poland.
    Sadowski, Janusz
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering. Polish Acad Sci, Poland.
    Wrobel, Jerzy
    Polish Acad Sci, Poland.
    Figielski, Tadeusz
    Polish Acad Sci, Poland.
    Wosinski, Tadeusz
    Polish Acad Sci, Poland.
    Tunable Planar Hall Effect in (Ga,Mn)(Bi,As) Epitaxial Layers2021In: Materials, E-ISSN 1996-1944, Vol. 14, no 16, article id 4483Article in journal (Refereed)
    Abstract [en]

    We have thoroughly investigated the planar Hall effect (PHE) in the epitaxial layers of the quaternary compound (Ga,Mn)(Bi,As). The addition of a small amount of heavy Bi atoms to the prototype dilute ferromagnetic semiconductor (Ga,Mn)As enhances significantly the spin-orbit coupling strength in its valence band, which essentially modifies certain magnetoelectric properties of the material. Our investigations demonstrate that an addition of just 1% Bi atomic fraction, substituting As atoms in the (Ga,Mn)As crystal lattice, causes an increase in the PHE magnitude by a factor of 2.5. Moreover, Bi incorporation into the layers strongly enhances their coercive fields and uniaxial magneto-crystalline anisotropy between the in-plane < 110 & rang; crystallographic directions in the layers grown under a compressive misfit strain. The displayed two-state behaviour of the PHE resistivity at zero magnetic field, which may be tuned by the control of applied field orientation, could be useful for application in spintronic devices, such as nonvolatile memory elements.

  • 25.
    Arslan, Mehmet Enes
    et al.
    Erzurum Tech Univ, Fac Sci, Dept Mol Biol & Genet, TR-25050 Erzurum, Turkey..
    Tatar, Arzu
    Ataturk Univ, Fac Med, Dept Otorhinolaryngol, TR-25240 Erzurum, Turkey..
    Yildirim, Ozge Caglar
    Erzurum Tech Univ, Fac Sci, Dept Mol Biol & Genet, TR-25050 Erzurum, Turkey..
    Sahin, Irfan Oguz
    Ondokuz Mayis Univ, Fac Med, Dept Pediat, Pediat Cardiol, TR-55139 Samsun, Turkey..
    Ozdemir, Ozlem
    Erzurum Tech Univ, Fac Sci, Dept Mol Biol & Genet, TR-25050 Erzurum, Turkey..
    Sonmez, Erdal
    Ataturk Univ, Grad Sch Nat & Appl Sci, Dept Nanosci & Nanoengn, Adv Mat Res Lab, TR-25240 Erzurum, Turkey..
    Hacimuftuoglu, Ahmet
    Ataturk Univ, Med Fac, Dept Med Pharmacol, TR-25240 Erzurum, Turkey..
    Acikyildiz, Metin
    Kilis 7 Aralik Univ, Dept Chem, Fac Sci, TR-79000 Kilis, Turkey..
    Geyikoglu, Fatime
    Ataturk Univ, Fac Arts & Sci, Dept Biol, TR-25240 Erzurum, Turkey..
    Mardinoglu, Adil
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Systems Biology. KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH Royal Inst Technol, Sci Life Lab, SE-17121 Stockholm, Sweden.;Kings Coll London, Fac Dent Oral & Craniofacial Sci, Ctr Host Microbiome Interact, London SE1 9RT, England..
    Turkez, Hasan
    Ataturk Univ, Fac Med, Dept Med Biol, TR-25240 Erzurum, Turkey..
    In Vitro Transcriptome Analysis of Cobalt Boride Nanoparticles on Human Pulmonary Alveolar Cells2022In: Materials, E-ISSN 1996-1944, Vol. 15, no 23, article id 8683Article in journal (Refereed)
    Abstract [en]

    Nanobiotechnology influences many different areas, including the medical, food, energy, clothing, and cosmetics industries. Considering the wide usage of nanomaterials, it is necessary to investigate the toxicity potentials of specific nanosized molecules. Boron-containing nanoparticles (NPs) are attracting much interest from scientists due to their unique physicochemical properties. However, there is limited information concerning the toxicity of boron-containing NPs, including cobalt boride (Co2B) NPs. Therefore, in this study, Co2B NPs were characterized using X-ray crystallography (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX) techniques. Then, we performed 3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH) release, and neutral red (NR) assays for assessing cell viability against Co2B NP exposure on cultured human pulmonary alveolar epithelial cells (HPAEpiC). In addition, whole-genome microarray analysis was carried out to reveal the global gene expression differentiation of HPAEpiC cells after Co2B NP application. The cell viability tests unveiled an IC50 value for Co2B NPs of 310.353 mg/L. The results of our microarray analysis displayed 719 gene expression differentiations (FC >= 2) among the analyzed 40,000 genes. The performed visualization and integrated discovery (DAVID) analysis revealed that there were interactions between various gene pathways and administration of the NPs. Based on gene ontology biological processes analysis, we found that the P53 signaling pathway, cell cycle, and cancer-affecting genes were mostly affected by the Co2B NPs. In conclusion, we suggested that Co2B NPs would be a safe and effective nanomolecule for industrial applications, particularly for medical purposes.

  • 26.
    Ashraf, Shakeel
    et al.
    Mid Sweden Univ, Dept Elect, S-85170 Sundsvall, Sweden..
    Forsberg, Viviane
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Mattsson, Claes G.
    Mid Sweden Univ, Dept Elect, S-85170 Sundsvall, Sweden..
    Thungström, Göran
    Mid Sweden Univ, Dept Elect, S-85170 Sundsvall, Sweden..
    Thermoelectric Properties of n-Type Molybdenum Disulfide (MoS2) Thin Film by Using a Simple Measurement Method2019In: Materials, E-ISSN 1996-1944, Vol. 12, no 21, article id 3521Article in journal (Refereed)
    Abstract [en]

    In this paper, a micrometre thin film of molybdenum disulfide (MoS2) is characterized for thermoelectric properties. The sample was prepared through mechanical exfoliation of a molybdenite crystal. The Seebeck coefficient measurement was performed by generating a temperature gradient across the sample and recording the induced electrical voltage, and for this purpose a simple measurement setup was developed. In the measurement, platinum was utilized as reference material in the electrodes. The Seebeck value of MoS2 was estimated to be approximately -600 mu V/K at a temperature difference of 40 degrees C. The negative sign indicates that the polarity of the material is n-type. For measurement of the thermal conductivity, the sample was sandwiched between the heat source and the heat sink, and a steady-state power of 1.42 W was provided while monitoring the temperature difference across the sample. Based on Fourier's law of conduction, the thermal conductivity of the sample was estimated to be approximately 0.26 Wm(-1) K-. The electrical resistivity was estimated to be 29 Omega cm. The figure of merit of MoS2 was estimated to be 1.99 x 10(-4).

  • 27.
    Ashraf, Shakeel
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Forsberg, Viviane
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. KTH, Wallenberg Wood Science Center, Stockholm.
    Mattsson, Claes G.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Thermoelectric properties of n-type molybdenum disulfide (MoS2) thin film by using a simple measurement method2019In: Materials, E-ISSN 1996-1944, Vol. 12, no 21, article id 3521Article in journal (Refereed)
    Abstract [en]

    In this paper, a micrometre thin film of molybdenum disulfide (MoS2) is characterized for thermoelectric properties. The sample was prepared through mechanical exfoliation of a molybdenite crystal. The Seebeck coefficient measurement was performed by generating a temperature gradient across the sample and recording the induced electrical voltage, and for this purpose a simple measurement setup was developed. In the measurement, platinum was utilized as reference material in the electrodes. The Seebeck value of MoS2 was estimated to be approximately -600 μV/K at a temperature difference of 40 °C. The negative sign indicates that the polarity of the material is n-type. For measurement of the thermal conductivity, the sample was sandwiched between the heat source and the heat sink, and a steady-state power of 1.42Wwas provided while monitoring the temperature difference across the sample. Based on Fourier's law of conduction, the thermal conductivity of the sample was estimated to be approximately 0.26 Wm-1 K-. The electrical resistivity was estimated to be 29 W cm. The figure of merit of MoS2 was estimated to be 1.99 × 10-4. 

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  • 28.
    Asif, Muhammad H.
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Strålfors, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Brännmark, Cecilia
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Elinder, Fredrik
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Englund, Ulrika H
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Growth and Structure of ZnO Nanorods on a Sub-Micrometer Glass Pipette and Their Application as Intracellular Potentiometric Selective Ion Sensors2010In: Materials, E-ISSN 1996-1944, Vol. 3, p. 4657-4667Article in journal (Refereed)
    Abstract [en]

    This paper presents the growth and structure of ZnO nanorods on a sub-micrometer glass pipette and their application as an intracellular selective ion sensor. Highly oriented, vertical and aligned ZnO nanorods were grown on the tip of a borosilicate glass capillary (0.7 μm in diameter) by the low temperature aqueous chemical growth (ACG) technique. The relatively large surface-to-volume ratio of ZnO nanorods makes them attractive for electrochemical sensing. Transmission electron microscopy studies show that ZnO nanorods are single crystals and grow along the crystal’s c-axis. The ZnO nanorods were functionalized with a polymeric membrane for selective intracellular measurements of Na

     

    +. The membrane-coated ZnO nanorods exhibited a Na+-dependent electrochemical potential difference versus

    an Ag/AgCl reference micro-electrode within a wide concentration range from 0.5 mM to 100 mM. The fabrication of functionalized ZnO nanorods paves the way to sense a wide range of biochemical species at the intracellular level.

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  • 29.
    Asimi, Ali
    et al.
    Department of Mining and Metallurgical Engineering Yazd University, Yazd 89195-741, Iran. Bafgh Zinc Smelting Company (BZSC), Yazd 89195-741, Iran .
    Gharibi, Khodakaram
    Department of Mining and Metallurgical Engineering Yazd University, Yazd 89195-741, Iran.
    Abkhoshk, Emad
    Bafgh Zinc Smelting Company (BZSC), Yazd 89195-741, Iran.
    Moosakazemi, Farhad
    Chemical Engineering Department, Laval University, Québec, QC G1V 0A6, Canada. Beneficiation and Hydrometallurgy Research Group, Mineral Processing Research Center, Academic Center for Education, Culture and Research (ACECR) on TMU, Tehran 15119-43943, Iran.
    Chelgani, Saeed Chehreh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Effects of Operational Parameters on the Low Contaminant Jarosite Precipitation Process-an Industrial Scale Study2020In: Materials, E-ISSN 1996-1944, Vol. 13, no 20, article id 4662Article in journal (Refereed)
    Abstract [en]

    Jarosite precipitation process (JPP) is the most frequently used procedure for iron removal in the hydrometallurgical zinc extraction process. However, there is a gap in the knowledge of the relationship between operational parameters and the low contaminant JPP on the industrial scale. This study will address these issues by investigating the behavior of zinc calcine (ZC) as a neutralizing agent, exploring the source of zinc and iron through leaching experiments, and simulating the Jarosite process of the Bafgh Zinc Smelting Company (BZSC). The results showed that the zinc dissolution efficiency was 90.3% at 90 °C, and 73% of the iron present in the calcine can be solubilized. The main outcome was the iron removal of about 85% by alkaline ions present in ZC without the addition of any precipitating agent. The second target was to evaluate the effect of operational parameters on jarosite precipitation. Results revealed that increasing the temperature to 90 °C and the stirring rate to 500 RPM as well as adjusting the ZC’s pH during the jarosite precipitation remarkably improved iron removal. Considering all these factors in the plant could improve Fe precipitation to around 80% on average.

  • 30.
    Attyabi, Seyed Nourallah
    et al.
    Advanced Magnetic Materials Research Center, School of Metallurgy and Materials, College of Engineering, University of Tehran, Tehran, 111554563, Iran.
    Radmanesh, Seyed Mohammad Ali
    Advanced Magnetic Materials Research Center, School of Metallurgy and Materials, College of Engineering, University of Tehran, Tehran, 111554563, Iran.
    Seyyed Ebrahimi, Seyyed Ali
    Advanced Magnetic Materials Research Center, School of Metallurgy and Materials, College of Engineering, University of Tehran, Tehran, 111554563, Iran.
    Dehghan, Hossein
    Advanced Magnetic Materials Research Center, School of Metallurgy and Materials, College of Engineering, University of Tehran, Tehran, 111554563, Iran.
    Lalegani, Zahra
    Advanced Magnetic Materials Research Center, School of Metallurgy and Materials, College of Engineering, University of Tehran, Tehran, 111554563, Iran.
    Hamawandi, Bejan
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Stress-Induced Grain Refinement in Hard Magnetic Mn52Al45.7C2.3 Fabricated Using the Ball-Milling Method2022In: Materials, E-ISSN 1996-1944, Vol. 15, no 22, article id 7919Article in journal (Refereed)
    Abstract [en]

    Mn52Al45.7C2.3 flakes with different sizes were prepared with two distinct surfactant-assisted ball-milling methods using cylindrical and barrel containers. Different microstructure and magnetic properties were measured based on the sequence of the container shape and different ball-milling times (2, 5, and 10 h). Morphology investigations showed that for powders milled in a barrel container, the amount of τ-phase was more compared to the samples milled in a cylindrical container. Moreover, in the powders milled with barrel containers, considerably higher magnetic properties were obtained in terms of saturation magnetization (Ms) and remanent magnetization (Mr) compared to those powders milled with cylindrical containers. Magnetic properties were found to be a function of the ball-milling time. High remanent magnetization and saturation magnetization have been found for powders milled in barrel containers, whereas only mediocre remanent magnetization and saturation magnetization have been measured in the case of milling in cylindrical containers. The highest Ms = 52.49 emu g−1 and Mr = 24.10 emu g−1 were obtained for the powders milled in barrel containers for 2 h. The higher magnetic properties taken from the milling in barrel containers is due to the higher shear stress and more uniform strain distribution induced by the barrel configuration, resulting in the stable τ-phase at a reasonably low-strain microstructure.

  • 31.
    Awsiuk, Kamil
    et al.
    Jagiellonian Univ, Poland.
    Dabczynski, Pawel
    Jagiellonian Univ, Poland.
    Marzec, Mateusz M.
    AGH Univ Sci & Technol, Poland..
    Rysz, Jakub
    Jagiellonian Univ, Poland..
    Moons, Ellen
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Physics (from 2013).
    Budkowski, Andrzej
    Jagiellonian Univ, Poland.
    Electrically Switchable Film Structure of Conjugated Polymer Composites2022In: Materials, E-ISSN 1996-1944, Vol. 15, no 6, article id 2219Article in journal (Refereed)
    Abstract [en]

    Domains rich in different blend components phase-separate during deposition, creating a film morphology that determines the performance of active layers in organic electronics. However, morphological control either relies on additional fabrication steps or is limited to a small region where an external interaction is applied. Here, we show that different semiconductor-insulator polymer composites can be rapidly dip-coated with the film structure electrically switched between distinct morphologies during deposition guided by the meniscus formed between the stationary barrier and horizontally drawn solid substrate. Reversible and repeatable changes between the morphologies used in devices, e.g., lateral morphologies and stratified layers of semiconductors and insulators, or between phase-inverted droplet-like structures are manifested only for one polarity of the voltage applied across the meniscus as a rectangular pulse. This phenomenon points to a novel mechanism, related to voltage-induced doping and the doping-dependent solubility of the conjugated polymer, equivalent to an increased semiconductor content that controls the composite morphologies. This is effective only for the positively polarized substrate rather than the barrier, as the former entrains the nearby lower part of the coating solution that forms the final composite film. The mechanism, applied to the pristine semiconductor solution, results in an increased semiconductor deposition and 40-times higher film conductance.

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  • 32.
    Azadpour, Behnam
    et al.
    Univ Tehran, Coll Engn, Adv Magnet Mat Res Ctr, Sch Met & Mat, Tehran 111554563, Iran.;Univ Tehran, Coll Sci, Sch Biol, Tehran 111554563, Iran..
    Kashanian, Faezeh
    Univ Tehran, Coll Sci, Sch Biol, Tehran 111554563, Iran..
    Habibi-Rezaei, Mehran
    Univ Tehran, Coll Sci, Sch Biol, Tehran 111554563, Iran..
    Ebrahimi, Seyyed Ali Seyyed
    Univ Tehran, Coll Engn, Adv Magnet Mat Res Ctr, Sch Met & Mat, Tehran 111554563, Iran..
    Yazdanpanah, Roozbeh
    Univ Tehran, Coll Engn, Adv Magnet Mat Res Ctr, Sch Met & Mat, Tehran 111554563, Iran.;Univ Tehran, Coll Sci, Sch Biol, Tehran 111554563, Iran..
    Lalegani, Zahra
    Univ Tehran, Coll Engn, Adv Magnet Mat Res Ctr, Sch Met & Mat, Tehran 111554563, Iran..
    Hamawandi, Bejan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Covalently-Bonded Coating of L-Arginine Modified Magnetic Nanoparticles with Dextran Using Co-Precipitation Method2022In: Materials, E-ISSN 1996-1944, Vol. 15, no 24, article id 8762Article in journal (Refereed)
    Abstract [en]

    In this study, L-arginine (Arg) modified magnetite (Fe3O4) nanoparticles (RMNPs) were firstly synthesized through a one-step co-precipitation method, and then these aminated nanoparticles (NPs) were, again, coated by pre-oxidized dextran (Dext), in which aldehyde groups (DextCHO) have been introduced on the polymer chain successfully via a strong chemical linkage. Arg, an amino acid, acts as a mediator to link the Dext to a magnetic core. The as-synthesized Arg-modified and Dext-coated arginine modified Fe3O4 NPs were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM). Both synthesized samples, XRD pattern and FT-IR spectra proved that the core is magnetite. FT-IR confirmed that the chemical bonds of Arg and Dext both exist in the samples. SEM images showed that the NPs are spherical and have an acceptable distribution size, and the VSM analysis indicated the superparamagnetic behavior of samples. The saturation magnetization was decreased after Dext coating, which confirms successive coating RMNPs with Text. In addition, the TGA analysis demonstrated that the prepared magnetic nanocomposites underwent various weight loss levels, which admitted the modification of magnetic cores with Arg and further coating with Dext.

  • 33.
    Babu, Bijish
    et al.
    Swerim AB, Heating and Metalworking, Luleå, Sweden.
    Lundbäck, Andreas
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Simulation of Ti-6Al-4V Additive Manufacturing Using Coupled Physically Based Flow Stress and Metallurgical Model2019In: Materials, E-ISSN 1996-1944, Vol. 12, no 23, article id 3844Article in journal (Refereed)
    Abstract [en]

    Simulating the additive manufacturing process of Ti-6Al-4V is very complex due to the microstructural changes and allotropic transformation occurring during its thermomechanical processing. The α -phase with a hexagonal close pack structure is present in three different forms—Widmanstatten, grain boundary and Martensite. A metallurgical model that computes the formation and dissolution of each of these phases was used here. Furthermore, a physically based flow-stress model coupled with the metallurgical model was applied in the simulation of an additive manufacturing case using the directed energy-deposition method. The result from the metallurgical model explicitly affects the mechanical properties in the flow-stress model. Validation of the thermal and mechanical model was performed by comparing the simulation results with measurements available in the literature, which showed good agreement

  • 34.
    Bae, Kichang
    et al.
    Pukyong Natl Univ, Dept Met Engn, Busan 48513, South Korea..
    Shin, Dongmin
    Pukyong Natl Univ, Dept Met Engn, Busan 48513, South Korea..
    Lee, Jonghun
    Pukyong Natl Univ, Dept Met Engn, Busan 48513, South Korea..
    Kim, Seohan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solid State Physics.
    Lee, Wookjin
    Pusan Natl Univ, Sch Mat Sci & Engn, Busan 46241, South Korea..
    Jo, Ilguk
    Dong Eui Univ, Adv Mat Engn, Busan 47340, South Korea..
    Lee, Junghoon
    Pukyong Natl Univ, Dept Met Engn, Busan 48513, South Korea..
    Corrosion Resistance of Laser Powder Bed Fused AISI 316L Stainless Steel and Effect of Direct Annealing2022In: Materials, E-ISSN 1996-1944, Vol. 15, no 18, article id 6336Article in journal (Refereed)
    Abstract [en]

    Alloy parts produced by an additive manufacturing method with rapid heat transfer from fast melting and solidification have different microstructures, characteristics, and performances compared with materials made by the conventional process. In this study, the corrosion and oxidation resistance of SS316L, which was prepared by the powder bed fusion process, was compared with those of cold-rolled SS316L. Additionally, the surface oxide film on stainless steel was thoroughly assessed since the film has the greatest influence on the corrosion and oxidation resistance. The effect of heat treatment on corrosion and oxidation resistance of SS316L fabricated by additive manufacturing was investigated. The SS316L has a microstructure formed by sub-grain cells, in which locally concentrated alloying elements form a stable passive film. As a result, it has a higher level of corrosion resistance and oxidation resistance than conventional cold-rolled materials. However, it was confirmed that the sub-grain cell was removed by heat treatment, which resulted in the degradation of corrosion and oxidation resistance.

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    FULLTEXT01
  • 35.
    Baghdadchi, Amir
    et al.
    University West, Department of Engineering Science, Division of Welding Technology.
    Hosseini, Vahid
    University West, Department of Engineering Science, Division of Welding Technology.
    Valiente Bermejo, María Asunción
    University West, Department of Engineering Science, Division of Welding Technology.
    Axelsson, Björn
    Alfa Laval Tumba AB, Tumba (SWE).
    Harati, Ebrahim
    University West, Department of Engineering Science, Division of Welding Technology. ITW Welding AB,Partille (SWE).
    Högström, Mats
    University West, Department of Engineering Science, Division of Welding Technology.
    Karlsson, Leif
    University West, Department of Engineering Science, Research Enviroment Production Technology West. University West, Department of Engineering Science, Division of Welding Technology.
    Wire laser metal deposition additive manufacturing of duplex stainless steel components -Development of a systematic methodology2021In: Materials, E-ISSN 1996-1944, Vol. 14, no 23, article id 7170Article in journal (Refereed)
    Abstract [en]

    A systematic four-stage methodology was developed and applied to the Laser Metal Deposition with Wire (LMDw) of a duplex stainless steel (DSS) cylinder > 20 kg. In the four stages, single-bead passes, a single-bead wall, a block, and finally a cylinder were produced. This stepwise approach allowed the development of LMDw process parameters and control systems while the volume of deposited material and the geometrical complexity of components increased. The as-deposited microstructure was inhomogeneous and repetitive, consisting of highly ferritic regions with nitrides and regions with high fractions of austenite. However, there were no cracks or lack of fusion defects; there were only some small pores, and strength and toughness were comparable to those of the corresponding steel grade. A heat treatment for 1 h at 1100 degrees (C) was performed to homogenize the microstructure, remove nitrides, and balance the ferrite and austenite fractions compensating for nitrogen loss occurring during LMDw. The heat treatment increased toughness and ductility and decreased strength, but these still matched steel properties. It was concluded that implementing a systematic methodology with a stepwise increase in the deposited volume and geometrical complexity is a cost-effective way of developing additive manufacturing procedures for the production of significantly sized metallic components.

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    Materials
  • 36.
    Balachandramurthi, Arun Ramanathan
    et al.
    Univ West, Sweden.
    Jaladurgam, Nitesh Raj
    Chalmers Univ Technol, Sweden.
    Kumara, Chamara
    Univ West, Sweden.
    Hansson, Thomas
    Univ West, Sweden; GKN Aerosp Sweden AB, Sweden.
    Moverare, Johan
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering. Univ West, Sweden.
    Gardstam, Johannes
    Qunitus Technol AB, Sweden.
    Pederson, Robert
    Univ West, Sweden.
    On the Microstructure of Laser Beam Powder Bed Fusion Alloy 718 and Its Influence on the Low Cycle Fatigue Behaviour2020In: Materials, E-ISSN 1996-1944, Vol. 13, no 22, article id 5198Article in journal (Refereed)
    Abstract [en]

    Additive manufacturing of Alloy 718 has become a popular subject of research in recent years. Understanding the process-microstructure-property relationship of additively manufactured Alloy 718 is crucial for maturing the technology to manufacture critical components. Fatigue behaviour is a key mechanical property that is required in applications such as gas turbines. Therefore, in the present work, low cycle fatigue behaviour of Alloy 718 manufactured by laser beam powder bed fusion process has been investigated. The material was tested in as-built condition as well as after two different thermal post-treatments. Three orientations with respect to the building direction were tested to evaluate the anisotropy. Testing was performed at room temperature under controlled amplitudes of strain. It was found that defects, inclusions, strengthening precipitates, and Youngs modulus influence the fatigue behaviour under strain-controlled conditions. The strengthening precipitates affected the deformation mechanism as well as the cycle-dependent hardening/softening behaviour. The defects and the inclusions had a detrimental effect on fatigue life. The presence of Laves phase in LB-PBF Alloy 718 did not have a detrimental effect on fatigue life. Youngs modulus was anisotropic and it contributed to the anisotropy in strain-life relationship. Pseudo-elastic stress vs. fatigue life approach could be used to handle the modulus-induced anisotropy in the strain-life relationship.

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  • 37.
    Balachandramurthi, Arun Ramanathan
    et al.
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Jaladurgam, Nitesj Raj
    Chalmers University of Technology, Department of Physics, Gothenburg, SE-412 96, Sweden.
    Kumara, Chamara
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Hansson, Tomas
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing. GKN Aerospace Sweden AB, Trollhättan, SE-461 38, Sweden.
    Moverare, Johan
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing. Linköping University, Department of Management and Engineering, Linköping, SE 581 83, Sweden.
    Gårdstam, Johannes
    Qunitus Technologies AB, Västerås, SE-721 66, Sweden.
    Pederson, Robert
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    On the microstructure of laser beam powder bed fusion alloy 718 and its influence on the low cycle fatigue behaviour2020In: Materials, E-ISSN 1996-1944, Vol. 13, no 22, article id 5198Article in journal (Refereed)
    Abstract [en]

    Additive manufacturing of Alloy 718 has become a popular subject of research in recent years. Understanding the process-microstructure-property relationship of additively manufactured Alloy 718 is crucial for maturing the technology to manufacture critical components. Fatigue behaviour is a key mechanical property that is required in applications such as gas turbines. Therefore, in the present work, low cycle fatigue behaviour of Alloy 718 manufactured by laser beam powder bed fusion process has been investigated. The material was tested in as-built condition as well as after two different thermal post-treatments. Three orientations with respect to the building direction were tested to evaluate the anisotropy. Testing was performed at room temperature under controlled amplitudes of strain. It was found that defects, inclusions, strengthening precipitates, and Young’s modulus influence the fatigue behaviour under strain-controlled conditions. The strengthening precipitates affected the deformation mechanism as well as the cycle-dependent hardening/softening behaviour. The defects and the inclusions had a detrimental effect on fatigue life. The presence of Laves phase in LB-PBF Alloy 718 did not have a detrimental effect on fatigue life. Young’s modulus was anisotropic and it contributed to the anisotropy in strain-life relationship. Pseudo-elastic stress vs. fatigue life approach could be used to handle the modulus-induced anisotropy in the strain-life relationship. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

  • 38.
    Balachandramurthi, Arun Ramanathan
    et al.
    Univ West, Sweden.
    Moverare, Johan
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering. Univ West, Sweden.
    Mahade, Satyapal
    Univ West, Sweden.
    Pederson, Robert
    Univ West, Sweden.
    Additive Manufacturing of Alloy 718 via Electron Beam Melting: Effect of Post-Treatment on the Microstructure and the Mechanical Properties2019In: Materials, E-ISSN 1996-1944, Vol. 12, no 1, article id 68Article in journal (Refereed)
    Abstract [en]

    Alloy 718 finds application in gas turbine engine components, such as turbine disks, compressor blades and so forth, due to its excellent mechanical and corrosion properties at elevated temperatures. Electron beam melting (EBM) is a recent addition to the list of additive manufacturing processes and has shown the capability to produce components with unique microstructural features. In this work, Alloy 718 specimens were manufactured using the EBM process with a single batch of virgin plasma atomized powder. One set of as-built specimens was subjected to solution treatment and ageing (STA); another set of as-built specimens was subjected to hot isostatic pressing (HIP), followed by STA (and referred to as HIP+STA). Microstructural analysis of as-built specimens, STA specimens and HIP+STA specimens was carried out using optical microscopy and scanning electron microscopy. Typical columnar microstructure, which is a characteristic of the EBM manufactured alloy, was observed. Hardness evaluation of the as-built, STA and HIP+STA specimens showed that the post-treatments led to an increase in hardness in the range of similar to 50 HV1. Tensile properties of the three material conditions (as-built, STA and HIP+STA) were evaluated. Post-treatments lead to an increase in the yield strength (YS) and the ultimate tensile strength (UTS). HIP+STA led to improved elongation compared to STA due to the closure of defects but YS and UTS were comparable for the two post-treatment conditions. Fractographic analysis of the tensile tested specimens showed that the closure of shrinkage porosity and the partial healing of lack of fusion (LoF) defects were responsible for improved properties. Fatigue properties were evaluated in both STA and HIP+STA conditions. In addition, three surface conditions were also investigated, namely the raw as-built surface, the machined surface with the contour region and the machined surface without the contour region. Machining off the contour region completely together with HIP+STA led to significant improvement in fatigue performance.

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  • 39.
    Balachandramurthi Ramanathan, Arun
    et al.
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Moverare, Johan
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing. Linköping University, Department of Management and Engineering, SE 581 83 Linköping, Sweden.
    Mahade, Satyapal
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Pederson, Robert
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Additive Manufacturing of Alloy 718 via Electron Beam Melting: Effect of Post-Treatment on the Microstructure and the Mechanical Properties.2018In: Materials, E-ISSN 1996-1944, Vol. 12, no 1, article id E68Article in journal (Refereed)
    Abstract [en]

    Alloy 718 finds application in gas turbine engine components, such as turbine disks, compressor blades and so forth, due to its excellent mechanical and corrosion properties at elevated temperatures. Electron beam melting (EBM) is a recent addition to the list of additive manufacturing processes and has shown the capability to produce components with unique microstructural features. In this work, Alloy 718 specimens were manufactured using the EBM process with a single batch of virgin plasma atomized powder. One set of as-built specimens was subjected to solution treatment and ageing (STA); another set of as-built specimens was subjected to hot isostatic pressing (HIP), followed by STA (and referred to as HIP+STA). Microstructural analysis of as-built specimens, STA specimens and HIP+STA specimens was carried out using optical microscopy and scanning electron microscopy. Typical columnar microstructure, which is a characteristic of the EBM manufactured alloy, was observed. Hardness evaluation of the as-built, STA and HIP+STA specimens showed that the post-treatments led to an increase in hardness in the range of ~50 HV1. Tensile properties of the three material conditions (as-built, STA and HIP+STA) were evaluated. Post-treatments lead to an increase in the yield strength (YS) and the ultimate tensile strength (UTS). HIP+STA led to improved elongation compared to STA due to the closure of defects but YS and UTS were comparable for the two post-treatment conditions. Fractographic analysis of the tensile tested specimens showed that the closure of shrinkage porosity and the partial healing of lack of fusion (LoF) defects were responsible for improved properties. Fatigue properties were evaluated in both STA and HIP+STA conditions. In addition, three surface conditions were also investigated, namely the 'raw' as-built surface, the machined surface with the contour region and the machined surface without the contour region. Machining off the contour region completely together with HIP+STA led to significant improvement in fatigue performance.

  • 40.
    Bartkowiak, Tomasz
    et al.
    Poznan University of Technology, Poland.
    Berglund, Johan
    RISE Research Institutes of Sweden, Materials and Production, Manufacturing Processes. Chalmers University of Technology, Sweden.
    Brown, Christopher
    Worcester Polytechnic Institute, USA.
    Multiscale characterizations of surface anisotropies2020In: Materials, E-ISSN 1996-1944, Vol. 13, no 13, article id 3028Article in journal (Refereed)
    Abstract [en]

    Anisotropy can influence surface function and can be an indication of processing. These influences and indications include friction, wetting, and microwear. This article studies two methods for multiscale quantification and visualization of anisotropy. One uses multiscale curvature tensor analysis and shows anisotropy in horizontal coordinates i.e., topocentric. The other uses multiple bandpass filters (also known as sliding bandpass filters) applied prior to calculating anisotropy parameters, texture aspect ratios (Str) and texture directions (Std), showing anisotropy in horizontal directions only. Topographies were studied on two milled steel surfaces, one convex with an evident large scale, cylindrical form anisotropy, the other nominally flat with smaller scale anisotropies; a EDMed surface, an example of an isotropic surface; and an additively manufactured surface with pillar-like features. Curvature tensors contain the two principal curvatures, i.e., maximum and minimum curvatures, which are orthogonal, and their directions, at each location. Principal directions are plotted for each calculated location on each surface, at each scale considered. Histograms in horizontal coordinates show altitude and azimuth angles of principal curvatures, elucidating dominant texture directions at each scale. Str and Std do not show vertical components, i.e., altitudes, of anisotropy. Changes of anisotropy with scale categorically failed to be detected by traditional characterization methods used conventionally. These multiscale methods show clearly in several representations that anisotropy changes with scale on actual surface measurements with markedly different anisotropies.

  • 41.
    Beigi Kheradmand, Azam
    et al.
    Islamic Azad Univ, Shahrekord Branch, Dept Mech Engn, Shahrekord 8813733395, Iran..
    Mirdamadi, Shamseddin
    Islamic Azad Univ, Sci & Res Branch, Dept Mat Engn, Tehran 8244865179, Iran..
    Lalegani, Zahra
    Islamic Azad Univ, Shahrekord Branch, Young Researchers & Elite Club, Shahrekord 8813733395, Iran..
    Hamawandi, Bejan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Effect of Thermomechanical Treatment of Al-Zn-Mg-Cu with Minor Amount of Sc and Zr on the Mechanical Properties2022In: Materials, E-ISSN 1996-1944, Vol. 15, no 2, article id 589Article in journal (Refereed)
    Abstract [en]

    In this study, the mechanical and microstructural properties of Al-Zn-Mg-Cu-Zr cast alloy with 0.1% Sc under homogeneous, dissolution, and T6 and thermomechanical treatments with the aim of increasing the volume fraction of MgZn2. Al-3(Sc,Zr) reinforcing precipitates were examined by hardness, microscopic examinations, tensile tests and software analysis. The results showed that, firstly, the hardness results are well proportional to the results of the tensile properties of alloys and, secondly, the strength of the alloy with thermomechanical treatments compared to T6 treatments increased from 492 MPa to 620 MPa and the elongation increased from 8% to 17% and was 100% upgraded. Microstructural and fracture cross section investigations showed that Al-3(Sc,Zr) nanosize dispersoids were evenly distributed among MgZn2 dispersoids and the alloy fracture was of semi-ductile type and nanosize dispersoids less than 10 nm were observed at the end of the dimples in the fracture section. The volume fraction of nanosize dispersoids in the whole microstructure of thermomechanical treatment samples was also much higher than that of T6 heat treated samples, so that the percentage of Al-3(Sc,Zr) precipitates arrived from less than 1% in T6 operation to 8.28% in the quench-controlled thermomechanical operation (with 50% deformation). The quality index (QI) in thermomechanical treatment samples is 19% higher than T6 samples, so that this index has increased from 641 in T6 operation to 760 in samples under thermomechanical treatment due to precipitate morphology, volume fraction of precipitates, their uniform distribution in the matrix, and nano sized precipitates in samples under thermomechanical treatment.

  • 42.
    Bejjani, Roland
    et al.
    Department of Mechanical Engineering.
    Bamford, Erik
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Cedergren, Stefan
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Archenti, Andreas
    KTH, School of Industrial Engineering and Management (ITM), Centres, Design and Management of Manufacturing Systems, DMMS. KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Rashid, Amir
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Variations in the Surface Integrity of Ti-6Al-4V by Combinations of Additive and Subtractive Manufacturing Processes2020In: Materials, E-ISSN 1996-1944, Vol. 13, no 8, p. 1-24, article id 1825Article in journal (Refereed)
    Abstract [en]

    Additive manufacturing (AM) has recently been accorded considerable interest by manufacturers. Many manufacturing industries, amongst others in the aerospace sector, are already using AM parts or are investing in such manufacturing methods. Important material properties, such as microstructures, residual stress, and surface topography, can be affected by AM processes. In addition, a subtractive manufacturing (SM) process, such as machining, is required for finishing certain parts when accurate tolerances are required. This finish machining will subsequently affect the surface integrity and topography of the material. In this research work, we focused on the surface integrity of Ti-6Al-4V parts manufactured using three different types of AM and finished using an SM step. The aim of this study was to gain an understanding on how each process affects the resulting surface integrity of the material. It was found that each AM process affects the materials’ properties differently and that clear differences exist compared to a reference material manufactured using conventional methods. The newly generated surface was investigated after the SM step and each combination of AM/SM resulted in differences in surface integrity. It was found that different AM processes result in different microstructures which in turn affect surface integrity after the SM process.

  • 43. Bejjani, Roland
    et al.
    Salame, Charlie
    Olsson, Mikael
    Dalarna University, School of Information and Engineering, Materials Technology.
    An Experimental and Finite Element Approach for a Better Understanding of Ti-6Al-4V Behavior When Machining under Cryogenic Environment2021In: Materials, E-ISSN 1996-1944, Vol. 14, no 11, article id 2796Article in journal (Refereed)
    Abstract [en]

    Due to increasing demand in manufacturing industries, process optimization has become a major area of focus for researchers. This research optimizes the cryogenic machining of aerospace titanium alloy Ti-6Al-4V for industrial applications by studying the effect of varying the nozzle position using two parameters: the nozzle's separation distance from the tool-chip interface and its inclination angle with respect to the tool rake face. A finite element model (FEM) and computational fluid dynamics (CFD) model are used to simulate the cryogenic impingement of cryogenic carbon dioxide on the tool-workpiece geometry. Experiments are conducted to evaluate cutting forces, tool wear, and surface roughness of the workpiece, and the results are related to the CFD and FEM analyses. The nozzle location is shown to have a significant impact on the cutting temperatures and forces, reducing them by up to 45% and 46%, respectively, while the dominant parameter affecting the results is shown to be the separation distance. Cryogenic machining is shown to decrease adhesion-diffusion wear as well as macroscopic brittle chipping of the cutting insert compared to dry turning, while the workpiece surface roughness is found to decrease by 44% in the case of cryogenic machining.

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  • 44.
    Benedetti, Matteo
    et al.
    Department of Industrial Engineering, University of Trento, Italy.
    Klarin, Johanna
    Jönköping University, School of Engineering. Department of Industrial Engineering, University of Trento, Italy.
    Johansson, Frida
    Jönköping University, School of Engineering. Department of Industrial Engineering, University of Trento, Italy.
    Fontanari, Vigilio
    Department of Industrial Engineering, University of Trento, Italy.
    Luchin, Valerio
    Eurocoating SpA, Trento, Italy.
    Zappini, Gianluca
    Eurocoating SpA, Trento, Italy.
    Molinari, Alberto
    Department of Industrial Engineering, University of Trento, Italy.
    Study of the compression behaviour of Ti6Al4V trabecular structures produced by additive laser manufacturing2019In: Materials, E-ISSN 1996-1944, Vol. 12, no 9, article id 1471Article in journal (Refereed)
    Abstract [en]

    The aim of this paper was to investigate the compression properties of several trabecular structures produced by additive laser manufacturing of a Ti6Al4V, having different densities and unit cells. Filling space structures were investigated, with different unit cells characterized by both bending-dominated and stretching-dominated behaviour. The stiffness and yield strengthwere correlated to relative density according to the Gibson and Ashby model. For a constant porosity, the stiffness and the yield strength varied between two extremes represented by the cubic structure (stretching-dominated deformation) and the cross structure (bending-dominated deformation). The properties of the deformed structures did not differ substantially from those of the regular structures. Only in the cubic structure did distortion enhance the contribution of bending to deformation and both stiffness and strength decreased. Cross structures displayed the highest strength at constant stiffness than the others, since they are characterized by the most favourable orientation of the struts. 

  • 45.
    Bernaczyk, Arkadiusz
    et al.
    Jowat SE, Detmold, 32758, Germany.
    Wagenführ, André
    Institute of Natural Materials Technology, Technische Universität Dresden, Dresden, 01062, Germany.
    Terfloth, Christian
    Jowat SE, Detmold, 32758, Germany.
    Lincke, Jörg
    Jowat SE, Detmold, 32758, Germany.
    Krystofiak, Tomasz
    Department of Wood Science and Thermal Techniques, Poznań University of Life Sciences, Poznan, 60-627, Poland.
    Niemz, Peter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering. Institute for Building Materials, ETH Zurich, 971 87 Luleå, Sweden.
    Investigations into the Influence of Temperature on the Tensile Shear Strength of Various Adhesives2023In: Materials, E-ISSN 1996-1944, Vol. 16, no 18, article id 6173Article in journal (Refereed)
    Abstract [en]

    The temperature resistance of glued timber, which is crucial for glued wood construction, represents a significant assessment criterion. To gain insights into this aspect, this study utilized methods such as a shear strength test in accordance with EN 302-1:2013-06 under thermal loading (from 20 °C to 200 °C), and Differential Scanning Calorimetry (DSC) to determine the glass transition temperature (Tg). An increase in thermal load resulted in a decrease in shear strength and an increase in wood breakage. A hierarchy of adhesive groups was established based on strength performance and wood failure percentage (WFP) at 200 °C. Thermoset adhesives (MF: Melamine Formaldehyde, PRF: Phenol Resorcinol Formaldehyde) led the ranking, followed by elastomer adhesives (1C-PUR: One-Component Polyurethane, EPI: Emulsion Polymer Isocyanate), with thermoplastic adhesive (PVAc: Polyvinyl Acetate) last. Thermoset adhesives further cured under heat. PUR adhesives exhibited higher strength performance at 150 °C and lower temperatures.

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  • 46.
    Bernaczyk, Arkadiusz
    et al.
    Jowat SE, 32758 Detmold, Germany.
    Wagenführ, André
    Institute of Natural Materials Technology, Technische Universität Dresden, 01062 Dresden, Germany.
    Zboray, Robert
    Center for X-ray Analytics, Empa—Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland.
    Flisch, Alexander
    Institute of Materials Science, Technische Universität Dresden, 01062 Dresden, Germany.
    Lüthi, Thomas
    Center for X-ray Analytics, Empa—Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland.
    Vetter, Birgit
    Institute of Materials Science, Technische Universität Dresden, 01062 Dresden, Germany.
    Rentsch, Mario
    Institute of Materials Science, Technische Universität Dresden, 01062 Dresden, Germany.
    Terfloth, Christian
    Jowat SE, 32758 Detmold, Germany.
    Lincke, Jörg
    Jowat SE, 32758 Detmold, Germany.
    Krystofiak, Tomasz
    Department of Wood Science and Thermal Techniques, Poznań University of Life Sciences, 60-627 Poznan, Poland.
    Niemz, Peter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Investigations on the Characterization of Various Adhesive Joints by Means of Nanoindentation and Computer Tomography2022In: Materials, E-ISSN 1996-1944, Vol. 15, no 23, p. 8604-8604Article in journal (Refereed)
    Abstract [en]

    The mechanical properties of cured wood adhesive films were tested in a dry state by means of nanoindentation. These studies have found that the application of adhesives have an effect on the accuracy of the hardness and elastic modulus determination. The highest values of hardness among the tested adhesives at 20 °C have condensation resins: MF (0.64 GPa) and RPF (0.52 GPa). Then the decreasing EPI (0.43 GPa), PUR (0.23 GPa) and PVAc (0.14 GPa) adhesives. The values of the elastic modulus look a little bit different. The highest values among the tested adhesives at 20 °C have EPI (11.97 GPa), followed by MF (10.54 GPa), RPF (7.98 GPa), PVAc (4.71 GPa) and PUR (3.37 GPa). X-ray micro-computed tomography was used to evaluate the adhesive joint by the determination of the voids. It has been proven that this value depends on the type of adhesive, glue quantity and reactivity. The highest values of the void ratio achieve the PUR (17.26%) adhesives, then PVAc (13.97%), RRF (6.88%), MF (1.78%) and EPI (0.03%). The ratio of the gaps increases with the higher joint thickness. A too high proportion of voids may weaken the adhesive joint.

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  • 47.
    Blomberg, Sara
    et al.
    Lund University, Sweden; Lawrence Berkeley National Laboratory, US.
    Johansson, Niclas
    Lund University, Sweden.
    Kokkonen, Esko
    Lund University, Sweden.
    Rissler, Jenny
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation. Lund University, Sweden.
    Kollberg, Linnea
    SunCarbon, Sweden.
    Preger, Calle
    Lund University, Sweden.
    Franzén, Sara
    Lund University, Sweden.
    Messing, Maria
    Lund University, Sweden.
    Hulteberg, Christian
    Lund University, Sweden.
    Bimetallic nanoparticles as a model system for an industrial NiMo catalyst2019In: Materials, E-ISSN 1996-1944, Vol. 12, no 22, article id 3727Article in journal (Refereed)
    Abstract [en]

    An in-depth understanding of the reactionmechanismis required for the further development of Mo-based catalysts for biobased feedstocks. However, fundamental studies of industrial catalysts are challenging, and simplified systems are often used without direct comparison to their industrial counterparts. Here, we report on size-selected bimetallic NiMo nanoparticles as a candidate for a model catalyst that is directly compared to the industrial system to evaluate their industrial relevance. Both the nanoparticles and industrial supported NiMo catalysts were characterized using surface- and bulk-sensitive techniques. We found that the active Ni and Mo metals in the industrial catalyst are well dispersed and well mixed on the support, and that the interaction between Ni and Mo promotes the reduction of the Mo oxide. We successfully produced 25 nm NiMo alloyed nanoparticles with a narrow size distribution. Characterization of the nanoparticles showed that they have a metallic core with a native oxide shell with a high potential for use as a model system for fundamental studies of hydrotreating catalysts for biobased feedstocks. © 2019 by the authors.

  • 48. Borrega, M.
    et al.
    Hinkka, V.
    Hörhammer, H.
    Kataja, K.
    Kenttä, E.
    Ketoja, Jukka A.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Palmgren, R.
    Salo, M.
    Sundqvist-Andberg, H.
    Tanaka, A.
    Utilizing and Valorizing Oat and Barley Straw as an Alternative Source of Lignocellulosic Fibers2022In: Materials, E-ISSN 1996-1944, Vol. 15, no 21, article id 7826Article in journal (Refereed)
    Abstract [en]

    The transition to sustainable, biodegradable, and recyclable materials requires new sources of cellulose fibers that are already used in large volumes by forest industries. Oat and barley straws provide interesting alternatives to wood fibers in lightweight material applications because of their similar chemical composition. Here we investigate processing and material forming concepts, which would enable strong fiber network structures for various applications. The idea is to apply mild pretreatment processing that could be distributed locally so that the logistics of the raw material collection could be made efficient. The actual material production would then combine foam-forming and hot-pressing operations that allow using all fractions of fiber materials with minimal waste. We aimed to study the technical features of this type of processing on a laboratory scale. The homogeneity of the sheet samples was very much affected by whether the raw material was mechanically refined or not. Straw fibers did not form a bond spontaneously with one another after drying the sheets, but their effective bonding required a subsequent hot pressing operation. The mechanical properties of the formed materials were at a similar level as those of the conventional wood-fiber webs. In addition to the technical aspects of materials, we also discuss the business opportunities and system-level requirements of using straw as an alternative source of lignocellulosic fibers. 

  • 49.
    Borukhovich, Efim
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Ruhr Univ Bochum.
    Du, Guanxing
    Stratmann, Matthias
    Boeff, Martin
    Shchyglo, Oleg
    Hartmaier, Alexander
    Steinbach, Ingo
    Microstructure Design of Tempered Martensite by Atomistically Informed Full-Field Simulation: From Quenching to Fracture2016In: Materials, E-ISSN 1996-1944, Vol. 9, no 8, article id 673Article in journal (Refereed)
    Abstract [en]

    Martensitic steels form a material class with a versatile range of properties that can be selected by varying the processing chain. In order to study and design the desired processing with the minimal experimental effort, modeling tools are required. In this work, a full processing cycle from quenching over tempering to mechanical testing is simulated with a single modeling framework that combines the features of the phase-field method and a coupled chemo-mechanical approach. In order to perform the mechanical testing, the mechanical part is extended to the large deformations case and coupled to crystal plasticity and a linear damage model. The quenching process is governed by the austenite-martensite transformation. In the tempering step, carbon segregation to the grain boundaries and the resulting cementite formation occur. During mechanical testing, the obtained material sample undergoes a large deformation that leads to local failure. The initial formation of the damage zones is observed to happen next to the carbides, while the final damage morphology follows the martensite microstructure. This multi-scale approach can be applied to design optimal microstructures dependent on processing and materials composition.

  • 50.
    Botero, Carlos Alberto
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Şelte, A.
    Ramsperger, M.
    Maistro, G.
    Koptyug, Andrey
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Bäckström, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Sjöström, William
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Microstructural and mechanical evaluation of a cr-mo-v cold-work tool steel produced via electron beam melting (Ebm)2021In: Materials, E-ISSN 1996-1944, Vol. 14, no 11, article id 2963Article in journal (Refereed)
    Abstract [en]

    In this work, a highly alloyed cold work tool steel, Uddeholm Vanadis 4 Extra, was manufactured via the electron beam melting (EBM) technique. The corresponding material microstructure and carbide precipitation behavior as well as the microstructural changes after heat treatment were characterized, and key mechanical properties were investigated. In the as-built condition, the mi-crostructure consists of a discontinuous network of very fine primary Mo-and V-rich carbides dispersed in an auto-tempered martensite matrix together with ≈15% of retained austenite. Adjusted heat treatment procedures allowed optimizing the microstructure by the elimination of Mo-rich carbides and the precipitation of fine and different sized V-rich carbides, along with a decrease in the retained austenite content below 2%. Hardness response, compressive strength, and abrasive wear properties of the EBM-manufactured material are similar or superior to its as-HIP forged counterparts manufactured using traditional powder metallurgy route. In the material as built by EBM, an impact toughness of 16–17 J was achieved. Hot isostatic pressing (HIP) was applied in order to further increase ductility and to investigate its impact upon the microstructure and properties of the material. After HIPing with optimized protocols, the ductility increased over 20 J. 

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