6,966 research outputs found

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

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    For (CoCrFeMn)100−x_{100-x}Alx_{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_{100-x}Alx_{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_{100-x}Alx_{x}. The predictions agree with our present experimental findings, and other reported ones.Comment: 27 pages, 9 figures, 1 tabl

    What we don't know about time

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    String theory has transformed our understanding of geometry, topology and spacetime. Thus, for this special issue of Foundations of Physics commemorating "Forty Years of String Theory", it seems appropriate to step back and ask what we do not understand. As I will discuss, time remains the least understood concept in physical theory. While we have made significant progress in understanding space, our understanding of time has not progressed much beyond the level of a century ago when Einstein introduced the idea of space-time as a combined entity. Thus, I will raise a series of open questions about time, and will review some of the progress that has been made as a roadmap for the future.Comment: 15 pages; Essay for a special issue of Foundations of Physics commemorating "Forty years of string theory

    The binding requirements of monkey brain lysosomal enzymes their immobilised receptor protein

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    The lysosomal enzyme binding protein (receptor protein) isolated from monkey brain was immobilised on Sepharose 4B and used to study the binding of brain lysosomal enzymes. The immobilised protein could bind ß-D-glucosaminidase, α-D-mannosidase, α -L-fucosidase and ß-D-glucuronidase. The bound enzymes could be eluted either at an acid pH of 4.5 or by mannose 6-phosphate but not by a number of other sugars tested. Binding could be abolished by prior treatment of the lysosomal enzymes with sodium periodate. Alkaline phosphatase treatment of the enzymes did not prevent the binding of the lysosomal enzymes to the column but decreased their affinity, as seen by a shift in their elution profile, when a gradient elution with mannose 6-phosphate was employed. These results suggested that an 'uncovered' phosphate on the carbohydrate moiety of the enzymes was not essential for binding but can enhance the binding affinity

    Black holes and black branes in Lifshitz spacetimes

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    We construct analytic solutions describing black holes and black branes in asymptotically Lifshitz spacetimes with arbitrary dynamical exponent z and for arbitrary number of dimensions. The model considered consists of Einstein gravity with negative cosmological constant, a scalar, and N U(1) gauge fields with dilatonic-like couplings. We study the phase diagrams and thermodynamic instabilities of the solution, and find qualitative differences between the cases with 12.Comment: 27 pages, 10 figures; v2 references added, minor comments adde

    Performance Comparison of New Heuristic With Genetic Algorithm in Parallel Flow Line Set Up

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    A new heuristic has been developed to solve the problem in parallel flow line scheduling. It involves the minimization of the makespan by the optimal allocation of a finite number of jobs to finite number of lines in the first phase and the optimal sequencing of allocated jobs in each line in the second phase. Here new heuristic and genetic algorithm for analyzing the parallel flow line scheduling are discussed and executed on a set of randomly generated problems. The results obtained for the test problems suggest that the developed new heuristic can be used successfully to solve large scale parallel flow line scheduling problems
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