| 16131. |
- Huang, Shuo, et al.
(författare)
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Chemical ordering controlled thermo-elasticity of AlTiVCr1-xNbx high-entropy alloys
- 2020
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Ingår i: Acta Materialia. - : Pergamon Press. - 1359-6454 .- 1873-2453. ; 199, s. 53-62
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Tidskriftsartikel (refereegranskat)abstract
- The stability of constituent phases in multi-component system always plays a prominent role in tailoring their mechanical performance at elevated temperatures. In this work, we highlight a chemical ordering feature in the AlTiVCr1-xNbx (0 <= x <= 1) alloys with body-centered cubic crystal structure. The quantum-mechanical first-principle investigations of these alloys on the elemental distribution identify a family of B2 type of partially ordered configurations. We map out the elastic parameters in detail as a function of composition and temperature for disordered and partially ordered phases. A great sensitivity to the order-disorder transformation is revealed, especially for the Cr-rich system. Our results demonstrate that a proper control of the ordering level in these alloys can facilitate the optimal tuning of their mechanical performance while keeping the density almost unchanged. The study presented here further predicts that these alloys possess high specific stiffness, low thermal expansion, and large elastic softening resistance. It is demonstrated that the considered alloys have thermal and mechanical properties that compete with superalloys and other high temperature structural materials.
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| 16132. |
- Huang, Shuo, et al.
(författare)
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Combinatorial design of partial ordered Al-Cr-Mn-Co medium-entropy alloys for room temperature magnetic refrigeration applications
- 2023
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 123:4
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Tidskriftsartikel (refereegranskat)abstract
- Multi-component alloys have received increasing interest for functional applications in recent years. Here, we explore the magnetocaloric response for Al-Cr-Mn-Co medium-entropy alloys by integrated theoretical and experimental methods. Under the guidance of thermodynamic and ab initio calculations, a dual-phase system with large magnetic moment, i.e., Al50Cr19Mn19Co12, is synthesized, and the structural and magnetocaloric properties are confirmed via characterization. The obtained results indicate that the selected alloy exhibits a co-continuous mixture of a disordered body-centered cubic and an ordered B2 phase. The ab initio and Monte Carlo calculations indicate that the presence of the ordered B2 phase is responsible for the substantial magnetocaloric effect. The magnetization measurements demonstrated that this alloy undergoes a second-order magnetic transition with the Curie temperature of similar to 300 K. The magnetocaloric properties are examined using magnetic entropy change, refrigeration capacity, and adiabatic temperature change. The property-directed strategy explored here is intended to contribute to the study of potential multi-component alloys in magnetocaloric applications.
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| 16133. |
- Huang, Shuo, et al.
(författare)
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Magnetocaloric properties of melt-spun MnFe-rich high-entropy alloy
- 2021
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 119:14
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Tidskriftsartikel (refereegranskat)abstract
- High-entropy functional materials are of great interest in materials science and engineering community. In this work, ab initio electronic structure calculations of the phase stability and magnetic transition temperature of AlxCr0.25MnFeCo0.25-yNiy (x = 0-0.5, y = 0-0.25) alloys were performed to screen for compositions showing promising magnetocaloric properties in the vicinity of room temperature. The selected Al0.44Cr0.25MnFeCo0.05Ni0.2 alloy was synthesized via a rapid solidification technique and systematically characterized with respect to its structural and magnetocaloric properties. The results indicate that this alloy possesses a homogeneous microstructure based on an underlying body-centered cubic lattice and has a Curie temperature of & SIM;340 K. The temperature dependence of the adiabatic temperature change was evaluated using both direct and indirect methods. The ab initio-assisted design of 3d-metal-based high-entropy alloys, explored here, is intended to contribute to the development of magnetic refrigerators for room-temperature applications.
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| 16134. |
- Huang, Shuo, et al.
(författare)
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Mapping the magnetic transition temperatures for medium- and high-entropy alloys
- 2018
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Ingår i: Intermetallics (Barking). - : Elsevier. - 0966-9795 .- 1879-0216. ; 95, s. 80-84
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Tidskriftsartikel (refereegranskat)abstract
- Tailorable magnetic state near room temperature is very promising for several technological, including magnetocaloric applications. Here using first-principle alloy theory, we determine the Curie temperature (T-C) of a number of equiatomic medium- and high-entropy alloys with solid solution phases. All calculations are performed at the computed lattice parameters, which are in line with the available experimental data. Theory predicts a large crystal structure dependence of T-C, which explains the experimental observations under specified conditions. The sensitivity of the magnetic state to the crystal lattice is reflected by the magnetic exchange interactions entering the Heisenberg Hamiltonian. The analysis of the effect of composition on T-C allows researchers to explore chemistry-dependent trends and design new multi-component alloys with pre-assigned magnetic properties.
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| 16135. |
- Huang, Shuo, et al.
(författare)
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Vibrational entropy-enhanced magnetocaloric effect in Mn-rich high-entropy alloys
- 2021
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 119:8
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the AlxCr0.2MnFe0.5Co0.3Ni0.5 (0.3 <= x <= 0.7) high-entropy alloys by combining experimental and theoretical techniques. X-ray diffraction and magnetization measurements indicate that Al alters the crystal structure and the entropy change upon magnetization-demagnetization while keeping the Curie temperature almost unchanged. First-principles calculations of the vibrational, magnetic, electronic, and configurational entropies show that the leading entropy change is due to the magnetic and vibrational degrees of freedom. The presence of the body-centered-cubic phase, showing a sizable elastic softening upon magnetic transition, brings about the substantial magnetocaloric effect in this family of alloys.
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| 16136. |
- Huemer, Lars, et al.
(författare)
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The Becoming of Cermaq : The interplay between network influences and firm level control ambitions
- 2009
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Ingår i: The IMP Journal. - 2059-1403 .- 0809-7259. ; 3:3, s. 53-75
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we study the birth and development of an international company, Cermaq. International business, by definition, deals with space, and some business activities are performed across national boundaries. For instance, it can be a company situated in one country but buying from suppliers situated in other countries, selling to customers in other countries or making investments in production or R&D in other countries. Here, we focus on the interrelatedness between the focal firm’s HQ’s ambition to be in control of its own development, and the influence that it experiences from its evolving network. The interplay and possible tension between firm-level control and network influence is used further to understand the construction of identities in networks. We suggest that identities develop as a result of internal features and successful control; the internal features of others and their successful influence; and new demands created by either new positions in old networks or entering into entirely ‘new’ networks. Both space and time emerge as central in the development of firms and networks, where the overall business logic only can be understood in hindsight.
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| 16137. |
- Huerta Buitrago, B., et al.
(författare)
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Hazard assessment of sediments from a wetland system for treatment of landfill leachate using bioassays
- 2013
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Ingår i: Ecotoxicology and Environmental Safety. - Maryland Heights, MO : Elsevier BV. - 0147-6513 .- 1090-2414. ; 97, s. 255-262
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Tidskriftsartikel (refereegranskat)abstract
- Four bioassays were used in this study for the hazard assessment of sediments from sediment traps and several ponds in a treatment wetland for landfill leachate at Atleverket, Sweden. In the 6-day solid phase microbiotest with the sediment-dwelling crustacean Heterocypris incongruens both acute and chronic effects were observed with a gradual decrease and loss of toxicity with treatment in the wetland system. Some samples showed a low toxicity in porewater and only one sample was weakly toxic in the whole sediment test when assessed with Aliivibrio fischeri (Vibro fischeri). No genotoxicity was detected in the umu test. The toxicity response in the H4IIE- luc test evaluating the presence of dioxin-like compounds was considerably higher in the samples from the sediment traps. The hazard of the sediment therefore appears to be highest in the sediment traps and pond 1 with the methods employed. The result indicates that the wetland system has a design supporting the concentration and sequestration of toxic substances in the first part of the wetland. Based upon the results we suggest that hazard assessment of sediments from other treatment wetlands for landfill leachate should be conducted.
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| 16138. |
- Huerta-García, Elizabeth, et al.
(författare)
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Internalization of Titanium Dioxide Nanoparticles Is Mediated by Actin-Dependent Reorganization and Clathrin- and Dynamin-Mediated Endocytosis in H9c2 Rat Cardiomyoblasts
- 2019
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Ingår i: Chemical Research in Toxicology. - : American Chemical Society (ACS). - 0893-228X .- 1520-5010. ; 32:4, s. 578-588
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Tidskriftsartikel (refereegranskat)abstract
- Titanium dioxide nanoparticles (TiO2 NPs) are widely used for industrial and commercial applications. Once inside the body, they translocate into the bloodstream and reach different areas of the cardiovascular system including the heart, increasing the risk of developing cardiovascular diseases; consequently, the investigation of their interaction with cardiac cells is required. We previously showed that TiO2 NPs are internalized by H9c2 rat cardiomyoblasts, and here, we examined the molecular mechanisms underlying this process. TiO2 NPs internalization was evaluated by transmission electron microscopy, time-lapse microscopy, and flow cytometry. Changes in the actin cytoskeleton were studied by phalloidin staining. Endocytic uptake mechanisms for nanoparticles were probed with chemical inhibitors, whereas clathrin and dynamin expression was measured by Western blot. Cellular uptake of TiO2 NPs occurred early after 30 min exposure, and large aggregates were observed after 1 h. Actin cytoskeleton reorganization included cell elongation plus lower density and stability of actin fibers. Cytochalasin-D inhibited TiO2 NPs uptake, indicating actin-mediated internalization. Dynamin and clathrin levels increased early after TiO2 NPs exposure, and their inhibition reduced nanoparticle uptake. Therefore, TiO2 NPs internalization by H9c2 rat cardiomyoblasts involves actin cytoskeleton reorganization and clathrin/dynamin-mediated endocytosis.
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| 16139. |
- Huge-Brodin, Maria, 1966-, et al.
(författare)
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Delimiting the Logistics System : A delicate Problem in Assessing the Environmental Impact from Transport
- 2009
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Ingår i: Proceedings from the Annual NOFOMA conference. - Jönköping : JIBS. - 9789186345013 ; , s. 402-417
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Konferensbidrag (refereegranskat)abstract
- Purpose of this paper The purpose of the paper is to illustrate some of the difficulties associated with assessing the environmental performance of logistics systems. The paper focuses on the environmental effects of transports in the logistics system, and elaborates on the complexity of defining an adequate system. Design/methodology/approach This conceptual paper builds on theory and literature on systems in general, and specifically logistics systems, and the environmental assessment of them. In addition, mini-cases are used to illustrate the analysis. The cases are from different sectors. Primary data was collected through interviews and secondary data through official internet pages and internal documentation. Findings The result of the paper is a set of ”learning lessons” which aim at providing a deeper understanding of the system delimitation problem, specifically for the environmental assessment of logistics systems. Research limitations/implications (if applicable) The paper is conceptual, and provides mainly a basis for further research. The illustrations emanate from a limited number of sectors, although the system delimitation problem is of a general nature. What is original/value of paper The problem of defining system limits is often overlooked, why this paper provides support for a better understanding of the problems of delimitations of a system. The area of environmental assessment of logistics systems is still in its cradle, why this paper also contributes to that research field.
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| 16140. |
- Hügel, Dario, et al.
(författare)
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Anisotropic Harper-Hofstadter-Mott model : Competition between condensation and magnetic fields
- 2017
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 96:5
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Tidskriftsartikel (refereegranskat)abstract
- We derive the reciprocal cluster mean-field method to study the strongly-interacting bosonic Harper-Hofstadter-Mott model. The system exhibits a rich phase diagram featuring band insulating, striped superfluid, and supersolid phases. Furthermore, for finite hopping anisotropy we observe gapless uncondensed liquid phases at integer fillings, which are analyzed by exact diagonalization. The liquid phases at fillings 1 and 3 exhibit the same band fillings as the fermionic integer quantum Hall effect, while the phase at filling 2 is CT-symmetric with zero charge response. We discuss how these phases become gapped on a quasi-one-dimensional cylinder, leading to a quantized Hall response, which we characterize by introducing a suitable measure for non-trivial many-body topological properties. Incompressible metastable states at fractional filling are also observed, indicating competing fractional quantum Hall phases. The combination of reciprocal cluster mean-field and exact diagonalization yields a promising method to analyze the properties of bosonic lattice systems with non-trivial unit cells in the thermodynamic limit.
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