Accelerating computational modeling and design of high-entropy alloys

With huge design spaces for unique chemical and mechanical properties, we remove a roadblock to computational design of {high-entropy alloys} using a metaheuristic hybrid Cuckoo Search (CS) for "on-the-fly" construction of Super-Cell Random APproximates (SCRAPs) having targeted atomic site and pair probabilities on arbitrary crystal lattices. Our hybrid-CS schema overcomes large, discrete combinatorial optimization by ultrafast global solutions that scale linearly in system size and strongly in parallel, e.g. a 4-element, 128-atom model [a $10^{73+}$ space] is found in seconds -- a reduction of 13,000+ over current strategies. With model-generation eliminated as a bottleneck, computational alloy design can be performed that is currently impossible or impractical. We showcase the method for real alloys with varying short-range order. Being problem-agnostic, our hybrid-CS schema offers numerous applications in diverse fields.Comment: 10 pages, 6 figures, submitted to Nature Computational Scienc

Contactlesss Eddy Current Braking System in Automobiles

In mechanical type braking system which are being used now days to stop or retard the automobile by means of artificial frictional resistance. This causes skidding and wear & tear of the vehicle which may cause serious problems. If the speed of the vehicle is very high, then it will not provide high braking torque, which may cause less frictional resistance during braking action and it will cause problems like accidents. These drawbacks of mechanical type brakes can be overcome by a simple, effective and efficient mechanism of braking system which is called as �The Non contactless braking system or Eddy current braking System�. It is a non contact type braking system then it is an abrasion-free method for braking in automobiles. It makes use of the opposing tendency of Eddy current. Eddy current are the loops of or swirling electric current produced in a conductor,by changing the magnetic field .The change of magnetic field is required for generating flux by the principle of faraday law. In eddy currents braking energy such as kinetic energy transform into heat, which is an unused energy. In some applications, the useful energy is lost i.e not particularly desirable. But there are some practical applications such an application is the eddy current brake.[1]This paper report explores the working principle of eddy current brake mechanism. In eddy current braking, like a conventional friction brake, which is responsible for slowing an object, such as a train or a roller coaster etc. In the friction braking, the pressure is applied on two separate objects, but in eddy current braking an object is stopped by creating eddy currents through electromagnetic induction which creates resistance, and in turn either heat or electricity. For such a breaker, we give analytical formulas considering end effects for its magnetic field, eddy current distribution, forces according to the secondary relative permeability, and conductivity. The results given here are purely analytic.[2]The principle of braking in road vehicles involved the conversion of kinetic energy into heat. This heat energy conversion therefore demands and appropriate rate of heat dissipation if a reasonable temperature and performance stability are to be maintained. The electromagnetic brakes works in relatively cool condition thus it avoid problem that friction brake face by using a totally different working principle and installation location. By using electromagnetic braking as substitute retardation equipment, the friction braking may be used less as compared and therefore practically never reach high temperature. Thus by eddy current braking brakes have a longer life , and potential �brake fade� problem can be avoided, it is apparent that the electromagnetic brake is an essential compliment to the safe breaking of vehicles.[3

Effect of passive smoking as a risk factor for chronic obstructive pulmonary disease in normal healthy women

Background: Environmental tobacco smoke (ETS) is a risk factor for cardiovascular disease, asthma in children and lung cancer. There is a biological plausibility of ETS as a causal factor for COPD. Objectives of the study were to examine the effect of passive smoking on lung function in non-smoking healthy women and to co-relate the effects of passive smoke as a risk factor for COPD.Methods: 50 women between 20-40 years of age exposed to passive smoke at home and workplace were assessed by questionnaire. The pulmonary function tests were performed and the values of FEV1 and FVC were obtained by a spirometer.Results: Out of 50 women, 34 % at workplace, 54% at home and 12% at home and workplace were exposed. Mean age was 30.3 years. Mean±SD of FEV1 was 1.94±0.9, FVC was 2.54±1.06, FEV1/FVC was 73.5±10.06 predicted FEV1 % was 63.2±23.2. FEV1/FVC of women exposed at home and workplace was 70.84 indicating that they have higher chances of developing COPD later in life.Conclusions: Passive smoking represents a serious health hazard that can be prevented by health education campaigns

Tuning phase-stability and short-range order through Al-doping in (CoCrFeMn)100-xAlx high entropy alloys

For (CoCrFeMn)$_{100-x}$Al$_{x}$ high-entropy alloys, we investigate the phase evolution with increasing Al-content (0 $\le$ x $\le$ 20 at.%). From first-principles theory, the Al-doping drives the alloy structurally from FCC to BCC separated by a narrow two-phase region (FCC+BCC), which is well supported by our experiments. We highlight the effect of Al-doping on the formation enthalpy and electronic structure of (CoCrFeMn)$_{100-x}$Al$_{x}$ alloys. As chemical short-range order (SRO) in multicomponent alloys indicates the nascent local order (and entropy changes), as well as expected low-temperature ordering behavior, we use thermodynamic linear-response within density-functional theory to predict SRO and ordering transformation and temperatures inherent in (CoCrFeMn)$_{100-x}$Al$_{x}$. The predictions agree with our present experimental findings, and other reported ones.Comment: 27 pages, 9 figures, 1 tabl

Thermodynamic Analysis of Solar Heat Exchanger Assisted Ammonia-Water VARS System

This research focused on the importance of the Ammonia Water Vapour Absorption Refrigeration (VARS) system using solar heat exchangers. The thermal energy needed to operate the VARS through electrical energy can be saved by means of a solar heat exchanger during the daytime. In this case, the strong solution of NH3-H2O passed through a copper/aluminium pipe of the solar flat-plate collector. The top ceiling flat-plate collector is covered with transparent glass through which the solar radiation heats the pipe and the strong solution of NH3-H2O within it passes. Due to heating the NH3 vaporizes and separates out from the strong solution in the flash chamber. Then the vapour NH3 flows into the condenser due to the buoyancy effect. It is interesting to discern the significance of solar-assisted heat exchangers to operate VARS and save electrical energy during the daytime. However, the daytime temperate variation is due to solar radiation in the heat supplied to any solar heat exchanger. The performance of the heat exchanger is governed by the mass flow rate binary solution. The effectiveness significantly affects the COP of VARS. Moreover, the VARS operating cost is reduced