| 1. |
- Artemenko, A., et al.
(författare)
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Reference XPS spectra of amino acids
- 2021
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Konferensbidrag (refereegranskat)abstract
- In this report we present XPS data for five amino acids (AAs) (tryptophan, methionine, glutamine, glutamic acid, and arginine) with different side chain groups measured in solid state (powder form). The theoretically and experimentally obtained chemical structure of AAs are compared. Here, we analyse and discuss C 1 s, N 1 s, O 1s and S 2p core level binding energies, FWHMs, atomic concentrations of the functional groups in AAs. The experimentally obtained and theoretically calculated ratio of atomic concentrations are compared. The zwitterionic nature of methionine and glutamine in solid state was determined from protonated amino groups in N 1s peak and deprotonated carboxylic groups in the C 1s spectrum. The obtained XPS results for AAs well correspond with previously reported data.
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| 2. |
- Chabuk, A, et al.
(författare)
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Evaluation of the Groundwater Quality for Irrigation : Case Study of Hilla district, Babylon Province, Iraq
- 2020
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Konferensbidrag (refereegranskat)abstract
- A crisis of water scarcity in the world encouraged researchers, especially in the arid areas to know the nature and quality of all its sources regardless of surface water. The groundwater evaluation for irrigation was suggested by using the model of Water Quality Index for Irrigation (WQIIR) in the ArcMap/GIS Software. This model was applied to 48 wells distributed throughout the Hilla district, Babylon, Iraq. The samples of EC, Ca +2, Mg+2, Cl-1, Na +1, HCO3-1, and SAR for groundwater were collected from these wells during wet and dry seasons in 2016. The generated maps in GIS for the WQIIR model in both seasons were divided into categories based on restriction`s groundwater use for irrigation. These categories consisted of Severe Restriction (SR), High Restriction (HR), Moderate Restriction (MR), Low Restriction,and No Restriction. The areas values and their classification of restriction`s groundwater use for irrigation related to the five categories that resulted within the generated maps in GIS using the WQIIR model in the wet season (in km 2) were: 42.79 (SR), 407.05 (HR), 377.77 (MR), 32.39 (LR) and 0.23 (NR) respectively and for the dry season were as follows: 42.79 (SR), 407.05 (HR), 377.77 (MR), 32.39 (LR) and 0.23 (NR) respectively. The areas and the classification categories of restriction groundwater for irrigation calculated based on the values resulted from the WQIIR model have shown variation in the dry and wet seasons.
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| 3. |
- Elmquist, Lennart, 1967-, et al.
(författare)
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On the relation between primary and eutectic solidification structures in gray iron
- 2012
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Konferensbidrag (refereegranskat)abstract
- The solidification of hypoeutectic gray cast iron starts with the nucleation of primary austenite crystals. Before graphite is nucleated, and the eutectic structure is formed, these crystals start to grow as columnar or equiaxed dendrites. However, very little is known about these dendrites, and especially how they influence the subsequent eutectic structure. Besides, it has previously been shown that the primary solidification structure influences the formation of defects. Shrinkage porosity was found between the dendrites, in the grain boundaries, and the formation of the primary solidification structure was found to influence problems related to metal expansion penetration. Therefore a better understanding about the formation of this structure is of importance. In this work, different inoculants and their influence on the formation of the micro- and macrostructures has been investigated. The inoculants considered are commercially used inoculants, i.e. inoculants used in the foundries, as well as different iron powders. The addition of iron powder is used to promote the primary solidification structure. It is shown that the nucleation of the dendrites is influenced by the amount of iron powder. Secondary dendrite arm spacing is a quantitative measurement in the microstructure related to these dendrites, which in turn depends on the solidification time. Eutectic cell size, on the other hand, is found to depend on secondary dendrite arm spacing. It is shown how the addition of inoculants influences both primary and eutectic solidification structures, and how they are related to each other.
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| 4. |
- Frómeta, D., et al.
(författare)
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A new cracking resistance index based on fracture mechanics for high strength sheet metal ranking
- 2021
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Konferensbidrag (refereegranskat)abstract
- Driven by current safety and weight reduction policies in the automotive sector, the development of new high strength sheet metal products has experienced unprecedented growth in the last years. With the emergence of these high strength materials, new challenges related to their limited ductility and higher cracking susceptibility have also raised. Accordingly, the development of new fracture criteria accounting for the material's cracking resistance has become unavoidable. In this work, a new cracking resistance index (CRI) based on fracture mechanics is proposed to classify the crack propagation resistance (i.e. the fracture toughness) of high strength metal sheets. The index is based on the fracture energy obtained from tensile tests with sharp-notched specimens. The procedure is very fast and simple, comparable to a conventional tensile test, and it may be used as routine testing for quality control and material selection. The CRI is investigated for several advanced high strength steel (AHSS) sheets of 0.8-1.6 mm thickness with tensile strengths between 800 and 1800 MPa. The results show that the proposed index is suitable to rank high strength steel sheets according to their crack propagation resistance and it can be correlated to the material's crashworthiness and edge cracking resistance.
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| 5. |
- Lukina, I N, et al.
(författare)
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Effect of synthesis parameters on the structure and properties of carbon particles formed from amorphous fullerites
- 2020
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Konferensbidrag (refereegranskat)abstract
- The effect of high-pressure synthesis temperature on the structure and indentation characteristics of the superelastic hard carbon formed from amorphous fullerites and on the tribological properties of the Co-based composite materials (CM) reinforced by the particles of such carbon has been studied by Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM), indentation measurements, and tribological tests. It is shown that ball milling (for 48 h) of C60 fullerite crystals results in the amorphization of the product of fullerite transformation upon their high-pressure treatment at temperatures above the stability limit of fullerene molecule (~800°C). An increase in synthesis temperature at 8 GPa from 800°C to 1200°C leads to a gradual graphitization of the structure of amorphous fullerite derived carbon. This decreases its hardness and indentation modulus from 32 to 18 GPa and from 256 to 95 GPa, respectively, and increases the elastic recovery (from 80% to 86%). The best tribological characteristics of the CM are attained at the maximum particle hardness, which is realized in the CM synthesized at 800°C. When the synthesis temperature is elevated to 1200°C, the friction coefficient and wear rate of the CM increase, but they remain substantially lower than those of the matrix cobalt.
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| 6. |
- Parareda, S., et al.
(författare)
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Effect of heat treatment conditions on the fatigue resistance of press hardened 22MnB5 steel evaluated through rapid testing technique
- 2021
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Konferensbidrag (refereegranskat)abstract
- Fatigue strength is considered as a crucial parameter for automotive applications subjected to cyclic loads during their long service life, as chassis parts. The high yield stress of press hardened steels poses them as good candidates for lightweight solutions with improved fatigue resistance. However, their high strength leads to an increase in notch sensitivity which can ruin the whole part's integrity. This behaviour was observed in previous works on press hardened steels, where their high fatigue strength was significantly affected by the surface conditions and by heat treatment conditions. Nevertheless, press hardening steels are still good candidates to manufacture complex geometry parts reaching high performance.Aiming at increasing the existing knowledge on the fatigue behaviour of press hardened steels, this paper analyses the fatigue performance of boron steel (22MnB5) under different time austenitizing times. Fatigue resistance is evaluated using a novel rapid fatigue testing technique based on the stiffness evolution. The method permits a fast and reliable determination of the fatigue limit. Based on results obtained with this rapid testing method, the most suitable heat treatment to mitigate fatigue notch sensitivity and then achieving the best fatigue performance for chassis applications is discussed.
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| 7. |
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3rd International Conference on Material Engineering and Advanced Manufacturing Technology, 26–28 April 2019, Shanghai, China
- 2020
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Proceedings (redaktörskap) (refereegranskat)abstract
- We are very pleased to present the proceedings of the 3rd International Conference on Material Engineering and Advanced Manufacturing Technology (MEAMT 2019) that was held successfully under the auspices of IASED in Shanghai, China, April 26-28, 2019.The theme of the conference - Material Engineering and Advanced Manufacturing Technology - is of key importance to the science and technology and a sustainable industrial development. This conference promotes valuable contacts between academia and industry and addresses both basic research and the societal/industrial technological needs within Material Engineering and Advanced Manufacturing Technology.In this era of Industry 4.0, we hope that the conference provided applicable data/information, addressed the issues in the societal/industrial transformation, and facilitated exchange within and between academia and industry.We want to express our gratitude to the program chairs and all members of the advisory, publicity, and technical committees for their valuable time and advices. We are grateful to the world renowned scientists who acted as keynote speakers at the conference.After a rigorous review process, where each paper was reviewed by at least two reviewers, high quality papers were accepted for presentation at this conference. We would like to thank all the reviewers for their time, effort, and for completing their assignments on time albeit tight deadlines.Many thanks to the authors for their valuable contributions and to the attendees for their active participation.Finally, a big thank to the organizers who made this conference to yet another unforgettable experience.Nader AsnafiProfessor of Mechanical Engineering, Örebro University, Sweden Editor of the proceedings of MEAMT 2019 One behalf of the conference committee.
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| 8. |
- Asnafi, Nader, 1960-, et al.
(författare)
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Tailored boron steel sheet component properties by selective laser heat treatment
- 2016
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Konferensbidrag (refereegranskat)abstract
- This investigation is focused on the stamping behaviour of boron steel, the properties of which are modified by selective laser heat treatment. Both CO2 and fibre lasers are tested. By using different laser processing parameters, the hardening depth in the 1 mm thick boron steel sheet Boloc 02 is varied. Four routes are tested and verified. The forming operation (in which a so-called flexrail beam is produced) in all four routes is conducted at ambient (room) temperature. The Reference route comprises stamping of the sheet. The GridBlank route starts with selective laser heat treatment of the blank, after which the blank is allowed to cool down, moved to a hydraulic press and stamped. In the GridTube route, the blank is first stamped, after which the part is moved to a laser cell and selectively laser heat treated. The fourth route, the RapidLaser route, is similar to the GridBlank route, but a higher laser speed is used to promote higher total productivity. The GridBlank route results in the highest hardness values and the best shape accuracy. The initial sheet material exhibits a hardness of 200 HV, while the parts produced in the GridBlank route exhibit a hardness of 700 HV.
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| 9. |
- Barlo, Alexander, M.Sc. Eng. 1994-, et al.
(författare)
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Creating a Virtual Shadow of the Manufacturing of Automotive Components
- 2024
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Konferensbidrag (refereegranskat)abstract
- Within the automotive industry, there is an increasing demand for a paradigmshift in terms of which materials are used for the manufacturing of the automotive body. Globalclimate goals are forcing a rapid adaption of new, advanced, sustainable material grades suchas the fossil free steels and materials containing higher scrap content. With the introduction ofthese new and untested materials, methods for accounting for variation in material propertiesare needed directly in the press lines.The following study will focus on creating an initial virtual shadow of the manufacturing of aVolvo XC90 inner door panel through the application of Artificial Neural Networks (ANN). Thevirtual shadow differs from the concept of the digital twin by only being a virtual representationof the production line, with training data generated exclusively by numerical simulations, andhaving no automated communication with the physical press line control system. The virtualshadow can be used as an assistance to the press line operators to see how different press linesettings and material parameter variations will impact the quality of the stamped component.The study aims to validate the virtual shadow through accurate predictions of the materialdraw-in measured in the physical press line.
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| 10. |
- Barlo, Alexander, M.Sc. Eng. 1994-, et al.
(författare)
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Investigation of Temperature Impact on Friction Conditions in Running Production of Automotive Body Components
- 2024
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Konferensbidrag (refereegranskat)abstract
- During the running production of automotive body components drifts in theprocess window is seen causing problems with non-conforming parts. Up until now, these driftshave been counter-acted based on the knowledge and experience of the press line operators.This experience-based process control will however become more troublesome in the future asrecycled material grades will undoubtedly present larger in-coil variations in material parametersand effect also the friction conditions from component to component.The following study will present two cases from production of the Volvo XC60. For thetwo cases, the initial simulations made for the components showed a safe part, but duringrunning production failure occurred suspected to be due to temperature effects in the tribologysystem. The study will furthermore present updated simulations considering developing thermaleffects to replicate the failures, as well as present both standard and thermal simulations of theadjustments made in production.
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