1,601 research outputs found
Nanostructured gradient Co-Sn electrodeposits as alternative to Sn connector contacts
No full textAbstract not availableE.P. Georgiou, J.G. Buijnsters, H. Wang, D. Drees, A.K. Basak, J.-P. Celi
Surface engineering of stainless steel
No full textChromizing and plasma nitriding on steels have attracted interest from industrial sectors because of its attractive properties and ability to apply on different types of steels. This chapter investigates duplex treatment on different types of steels at different treatment conditions. The improvements of the treated surfaces in terms of morphology and thickness, composition, surface hardness and roughness, as well as wear and friction of the engineered layer on different ferrous alloys have been analysed. It was found that several layers of different thickness are formed due to duplex treatment which depends on the carbon content of specimen and temperature of the treatment. Mainly carbides and nitrides of chromium and iron are formed which is controlled by duplex treatment process parameters. These compounds enhance the hardness and wear resistance of the treated surface. The CrxN phase is the main contributor towards high microhardness of duplex treated layers. In addition to high hardness, it also provides excellent wear resistance properties. The plasma nitriding process reduces the coefficient of friction of chromized steels due to the lower friction coefficient of chromium nitride. However, the surface roughness of the treated surface increases due to the intrinsic properties of formed phases
Weldability and machinability of duplex stainless steel
No full textThis chapter investigates two important processing methods, such as welding and machine of duplex stainless steel. The welding process welding generally degrades the properties of these materials by redistributing the phases during melting and solidification. On the other hand, the redistribution during machining mainly take place combined effect of stress, strain rate and temperature. Mechanism of machining process and several welding methods has been analysed in details. It was found that outcomes of welding processes depend on the welding methods. Most of the cases an appropriate annealing process can be used to restore the expected properties of the weld joints though the parameters of annealing process are different in different welding methods. Non-metallic inclusions and the low carbon content of duplex stainless steel reduce the machinability of duplex stainless steel. SEM and optical microscopic details of the frozen cutting zone and chips revealed that the harder austenite phase dissipates in the advancement of the cutting tool, being effectively squeezed out of the softer ferrite phase. Abrasion and adhesion were the most common wear modes developed on the flank and rake faces. Adhesion wear being the most prevalent on the flank face, appeared to be initiated by built-up edge formation
Effect of nanostructuring and Al alloying on friction and wear behaviour of thermal sprayed WC-Co coatings
No full textAbstract not availableA.K. Basak, J.-P. Celis, M. Vardavoulias, P. Matteazz
Optimizing dimensional accuracy of titanium alloy features produced by wire electrical discharge machining
No full textThis study investigates geometrical errors such as cylindricity, circularity and diametral errors of a feature (a hole) produced from wire electrical discharge machining of Ti6Al4V alloy where tension in wire, pulse on time, and flushing pressure are varied. Pareto analysis of variance (ANOVA), Taguchi design of experiment (DoE), and traditional analysis estimate the influence of variables on errors of holes. It was noted that flushing pressure is the most significant factor with individual contributions of 31.02%, 49.5% and 37.84% to circularity, cylindricity, and diametral errors, respectively. The circularity error of holes decreases as the flushing pressure and tension in wire rise, but decreases with the rise of pulse on time. The cylindricity error decreased with the increase of wire tension, flushing pressure and pulse on time. The absolute diametral error reduced as the pulse on time and tension in wire raised, but it raised with the rise of pulse on time. All these trends are associated with the influence of tension in wire on the flexibility of wire, the dependence of heat generation and dissipation on pulse on time, and ability of the flushing pressure to control the cooling, as well as debris removal from the machining zone.A. Pramanik, M.N. Islam, A.K. Basak, Y. Dong, G. Littlefair, and C. Prakas
Maternal micronutrients, placental growth and fetal outcome
No full textPregnancy can be regarded as a three-compartment model, with the mother, placenta, and fetus interacting to ensure proper fetal growth and development. Maternal health, along with maternal diet, body composition, metabolism, and placental nutrient supply, is the main fac- tor that can negatively or positively influence fetal development. Before reaching the fetus, nutrients from maternal diet are used by the placenta for its own metabolism. The quality and quantity of nutrients that reach the fetus are indeed influenced by placental shape, size, and characteristics. Placental growth and develgpment are influenced by the maternal diet itself.
This chapter aims to show how fetal and postnatal growth and development are strictly dependent on proper maternal nutritional intake before and during pregnancy and how over- supply, deficiency, or poor quality of nutrients may influence placental development and adversely affect pregnancy outcome and expression offetal genetic potential
Flow over partially liquid filled cavity
No full textExperiments have been carried out to investigate the effect of liquid cavity filling on the behavior of the gas flow over a flat plate cavity. PIV measurements in the gas phase reveal that cavity filling can affect vortex shedding in the cavity mouth. Shear layer vortices can break-up into smaller vortices, thereby losing their periodic interaction with the aft wall and, hence, their sound producing potential. Expected is that this is one of the mechanisms causing sound mitigation in corrugated pipes with liquid addition, observed in literature
ADOPTION OF A CHILD WITHOUT CONSENT OF ITS PARENT WITH A INTELLECTUAL DISABILITY : CASE OF A.K. AND L. v. CROATIA
No full textThis paper discusses the matter of parents prior right to provide his/her child with care in situations in which a child’s parent is a person with intellectual disabilities. The author analyzes the case of A.K. and L. v. Croatia in which European Court of Human Rights concluded that it come to violation of the right to family life of A.K, a mother with an intellectual disability and her son L., who was adopted without the mother’s consent. The paper presents a critical review of Croatian family law in a matter of a parent’s consent for an adoption when the parent is a person with intellectual disabilities. By connecting contemporary standpoints of the European Court of Human Rights and the latest scientific knowledge about the ability of persons with intellectual disabilities to take care of their child, the author discusses a possible conflict between the principle of child’s best interest and the priority right of a parent to take care of his/her child. Also, the author warns about the danger of a parent with intellectual disabilities being deprived of his/her parental rights and completely excluded from the process of adoption even in situations when the parent could, with adequate professional help and support, maintain a family relationship with the child. From that perspective the author also discusses the latest reforms of the family law concerning protection of parental rights of persons deprived of their capacity for work
Lasing in Bose-Fermi mixtures
No full textA.K. acknowledges the support from the EPSRC Established Career Fellowship. V.K., M.D., V.F.S. and A.K. acknowledge support from the Russian Ministry of Science and Education, contract (contract No. 11.G34.31.0067). P.G.S. acknowledges support from Greek GSRT program Aristeia (grant No. 1978). C.S., M. A. J.F., M.K and S.H. acknowledge support from the state of Bavaria.Light amplification by stimulated emission of radiation, well-known for revolutionising photonic science, has been realised primarily in fermionic systems including widely applied diode lasers. The prerequisite for fermionic lasing is the inversion of electronic population, which governs the lasing threshold. More recently, bosonic lasers have also been developed based on Bose-Einstein condensates of exciton-polaritons in semiconductor microcavities. These electrically neutral bosons coexist with charged electrons and holes. In the presence of magnetic fields, the charged particles are bound to their cyclotron orbits, while the neutral exciton-polaritons move freely. We demonstrate how magnetic fields affect dramatically the phase diagram of mixed Bose-Fermi systems, switching between fermionic lasing, incoherent emission and bosonic lasing regimes in planar and pillar microcavities with optical and electrical pumping. We collected and analyzed the data taken on pillar and planar microcavity structures at continuous wave and pulsed optical excitation as well as injecting electrons and holes electronically. Our results evidence the transition from a Bose gas to a Fermi liquid mediated by magnetic fields and light-matter coupling.Peer reviewe
Stress in the interfaces of metal matrix composites (MMCs) in thermal and tensile loading
No full textThe influence of contents, sizes and shapes of reinforcements on the matrix-particle interfaces in terms of (a) von-Mises stress, (b) directions as well as spreading of principal stresses during cooling and under tension were analysed in this investigation through numerical simulation for SiC particle reinforced Al6061 matrix MMCs. The result shows that the rapid variation of von-Mises stress in the interfaces depends on the shape of reinforced particles. The interfaces in MMCs with triangular reinforcements experienced the slimiest stress variation. Nevertheless, the uppermost stress was intensified in the corners of the triangle shaped reinforcements. The shape of the reinforcements affects the stress vectors directions. The range of the von-Mises stress rises through the rise of particle amount and decrease of particles size at a constant number of particles. For nearly all the cases, excluding the MMCs with triangle reinforcements, when the stress rises, with the rise of the applied positive elongation, the stress scatterings are unaffected.A. Pramanik, A. K. Basak, G. Littlefair, A. R. Dixit, S. Chattopadhyay
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