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Shape Memory Effect and Superelasticity of [001]-Oriented FeNiCoAlNb Single Crystals Aged under and without Stress
(2021-06-10)
The two-step ageing of Fe-28Ni-17Co-11.5Al-2.5Nb (at.%) single crystals under and without stress, leads to the precipitation of the γ′- and β-phase particles. Research has shown that γ–α′ thermoelastic martensitic transformation (MT), with shape memory effect (SME) and superelasticity (SE), develops in the [001]-oriented crystals under tension. SE was observed within the range from the temperature of the start of MT upon cooling Mₛ, to the temperature of the end of the reverse MT upon heating Af, and at temperatures ...
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The Effect of Fiber Waviness on the Residual Stress State and Its Prediction by the Hole Drilling Method in Fiber Metal Laminates: A Global-Local Finite Element Analysis
(2021-01-15)
In this paper, fiber waviness, as one of the most frequently occurring defects in fiber reinforced composites, is numerically investigated with regard to the formation of residual stresses in fiber metal laminates. Furthermore, the prediction of the residual stress state in the thickness direction by means of the simulated hole drilling method is studied. To this regard, a global-local finite element analysis based on the submodel technique is presented. The submodel technique essentially consists of two governing ...
Aufsatz
Cyclic Crack Growth in Chemically Tailored Isotropic Austenitic Steel Processed by Electron Beam Powder Bed Fusion
(2021-11-01)
The present study analyzes the cyclic crack propagation behavior in an austenitic steel processed by electron beam powder bed fusion (PBF-EB). The threshold value of crack growth as well as the crack growth behavior in the Paris regime were studied. In contrast to other austenitic steels, the building direction during PBF-EB did not affect the crack propagation rate, i.e., the crack growth rates perpendicular and parallel to the building direction were similar due to the isotropic microstructure characterized by ...
Aufsatz
Tribological Performance of Additively Manufactured AISI H13 Steel in Different Surface Conditions
(2021-02-16)
Additive manufacturing of metallic tribological components offers unprecedented degrees of freedom, but the surface roughness of most as-printed surfaces impedes the direct applicability of such structures, and postprocessing is necessary. Here, the tribological performance of AISI H13 steel samples was studied. These were additively manufactured through laser powder bed fusion (L-PBF), also referred to as selective laser melting (SLM). Samples were tested in four different surface conditions: as-printed, polished, ...
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Overmoulding of Additively Manufactured Titanium Inserts Using Polyoxymethylene (POM)—Evaluation of Bond Quality as a Function of Process Parameters
(2021-06-15)
Due to their process-induced porous surfaces, additively manufactured structures are not optimized for applications in which friction is a key factor. To improve the frictional properties of additively manufactured titanium inserts of various thicknesses, two tribologically optimized POM materials, which differ in terms of filler composition and contents, were used to overmould the inserts. The titanium inserts were manufactured in two different building directions, resulting in a variation in surface roughness. The ...
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On the influence of ϰ-carbides on the low-cycle fatigue behavior of high-Mn light-weight steels
(2021)
High-manganese light-weight steels offer a great potential for structural purposes in the mobility sector due to their reduced density combined with outstanding mechanical properties. As many of the envisaged applications of these materials will suffer from cyclic loading during their service life, the fundamentals of their fatigue behavior must be studied extensively. In the present work, the low-cycle fatigue (LCF) properties of an austenitic Fe-29.8Mn-7.65Al-1.11C light-weight steel were investigated. Two ...
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Genotypic differences in body weight and physiological response of local and exotic turkeys challenged with Salmonella typhimurium
(2021-11-02)
To better understand susceptibility and/ or tolerance of locally adapted turkey to salmonellosis, we compared bodyweight, antibody titres and physiological traits based on genotype and sex of salmonella-infected turkeys. Three hundred poults from two genotypes (160 local and 140 exotic turkeys) were raised for twenty weeks. Bodyweight (BW), rectal temperature (RT), pulse rate (PR) and respiratory rate (RR) were measured weekly. Blood samples were collected from each turkey before and after inoculations at week 8 and ...
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Agricultural risk assessment to enhance the food systems of the Mbororo minority community in the Northwest region of Cameroon
(2021-10-29)
Increasing population pressure, coupled with the effects of climate change manifested by longer dry seasons, wildfires, and conflicts, threatens the food systems of minority communities. In the case of the Mbororo minority community of Northwest Region of Cameroon, these threats are exacerbated by already existing problems of marginalisation. This study assesses agricultural risks in the global context of food distribution and gross domestic product that also poses a specific threat to the food system of the Mbororo ...
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Preliminary assesment on drought tolerant oil palm in semi-arid area
(2021-12-15)
The evaluation of oil palm growth performance and their corresponding effect on drought very crucial in selection of proper parent’s tree. The parent palm that showed drought tolerance and have less effect on oil yield is important for optimisation semi-arid lands usage in future. The Split plot with two replications in a randomized complete block design (RCBD) were conducted and mixed stand with an adjacent control plot. All 19 progenies was evaluated and interaction effects are estimated using split plots analysis. ...
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Antioxidant activity of a mixture of water-soluble tempeh extract with whey powder that has undergone a Maillard reaction
(2021-12-20)
High amino acid content in tempeh and lactose in whey powder can be combined to perform Maillard reaction. So, it can be used to produce functional food products. This is caused by the formation of Amadori and melanoidin as water-soluble compounds which are reported to have high antioxidant capacity and produce a preferred flavor. The general objective of the study was to obtain an optimum process condition in a mixture of water soluble tempeh extract and whey powder with the highest antioxidant capacity (100 mL). ...