6,442 research outputs found

    Working-fluid selection and performance investigation of a two-phase single-reciprocating-piston heat-conversion engine

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    We employ a validated first-order lumped dynamic model of the Up-THERM converter, a two-phase unsteady heat-engine that belongs to a class of innovative devices known as thermofluidic oscillators, which contain fewer moving parts than conventional engines and represent an attractive alternative for remote or off-grid power generation as well as waste-heat recovery. We investigate the performance the Up-THERM with respect to working-fluid selection for its prospective applications. An examination of relevant working-fluid thermodynamic properties reveals that the saturation pressure and vapour-phase density of the fluid play important roles in determining the performance of the Up-THERM – the device delivers a higher power output at high saturation pressures and has higher exergy efficiencies at low vapour-phase densities. Furthermore, working fluids with low critical temperatures, high critical pressures and exhibiting high values of reduced pressures and temperatures result in designs with high power outputs. For a nominal Up-THERM design corresponding to a target application with a heat-source temperature of 360 ◦C, water is compared with forty-five other pure working fluids. When maximizing the power output, R113 is identified as the optimal fluid, followed by i-hexane. Fluids such as siloxanes and heavier hydrocarbons are found to maximize the exergy and thermal efficiencies. The ability of the Up-THERM to convert heat over a range of heat-source temperatures is also investigated, and it is found that the device can deliver in excess of 10 kW when utilizing thermal energy at temperatures above 200 ◦C. Of all the working fluids considered here, ammonia, R245ca, R32, propene and butane feature prominently as optimal and versatile fluids delivering high power over a wide range of heat-source temperatures

    Characterization and Oxidative Addition Reactions of Different Rhodium and Iridium Triazolato Complexes

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    A number of different rhodium(I) and iridium(I) triazolato complexes and their oxidative addition products (triazolate = 3,5-bis(pyridine-2-yl)-1,2,4 triazolate (bpt–) and 4-amino-3,5-bis(pyridine-2-yl)-1,2,4-triazolate (bpt-NH–)) were prepared and characterized by means of IR and 1HNMR spectroscopy, elemental analysis and computational chemistry methods. The oxidative addition reactions of these complexes with iodomethane in different solvents indicated simple second-order kinetics with the faster reactions in the more polar solvents (1.44(7) × 10–2 L mol–1 s–1 in dichloromethane compared with 9.2(5) × 10–4 L mol–1 s–1 in benzene for iridium bpt-NH). 1HNMRdata and density functional theory calculations illustrate that the coordination of the metal centre in [M(bpt-NH)(cod)] (M = Rh or Ir) occurs via the amine moiety and a nitrogen of a pyridine ring.Keywords: Rhodium(I), Iridium(I), Triazole, Cyclooctadiene, Oxidative Addition, Methyl Iodide, DFTAttached PDF and Supplementary Fil

    Rab11-FIP1/RCP functions as a major signalling hub in the oncogenic roles of mutant p53 in cancer

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    Rab11-FIP1 is a Rab effector protein that is involved in endosomal recycling and trafficking of various molecules throughout the endocytic compartments of the cell. The consequence of this can be increased secretion or increased membrane expression of those molecules. In general, expression of Rab11-FIP1 coincides with more tumourigenic and metastatic cell behaviour. Rab11-FIP1 can work in concert with oncogenes such as mutant p53, but has also been speculated to be an oncogene in its own right. In this perspective, we will discuss and speculate upon our observations that mutant p53 promotes Rab11-FIP1 function to not only promote invasive behaviour, but also chemoresistance by regulating a multitude of different proteins

    IDO1 (indoleamine 2,3-dioxygenase 1)

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    Review on IDO1 (indoleamine 2,3-dioxygenase 1), with data on DNA, on the protein encoded, and where the gene is implicated

    Improving the performance of bright quantum dot single photon sources using amplitude modulation

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    Single epitaxially-grown semiconductor quantum dots have great potential as single photon sources for photonic quantum technologies, though in practice devices often exhibit non-ideal behavior. Here, we demonstrate that amplitude modulation can improve the performance of quantum-dot-based sources. Starting with a bright source consisting of a single quantum dot in a fiber-coupled microdisk cavity, we use synchronized amplitude modulation to temporally filter the emitted light. We observe that the single photon purity, temporal overlap between successive emission events, and indistinguishability can be greatly improved with this technique. As this method can be applied to any triggered single photon source, independent of geometry and after device fabrication, it is a flexible approach to improve the performance of solid-state systems, which often suffer from excess dephasing and multi-photon background emission

    IDO2 (indoleamine 2,3-dioxygenase 2)

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    Review on IDO2 (indoleamine 2,3-dioxygenase 2), with data on DNA, on the protein encoded, and where the gene is implicated

    Electric-field-induced coherent coupling of the exciton states in a single quantum dot

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    The signature of coherent coupling between two quantum states is an anticrossing in their energies as one is swept through the other. In single semiconductor quantum dots containing an electron-hole pair the eigenstates form a two-level system that can be used to demonstrate quantum effects in the solid state, but in all previous work these states were independent. Here we describe a technique to control the energetic splitting of these states using a vertical electric field, facilitating the observation of coherent coupling between them. Near the minimum splitting the eigenstates rotate in the plane of the sample, being orientated at 45{\deg} when the splitting is smallest. Using this system we show direct control over the exciton states in one quantum dot, leading to the generation of entangled photon pairs
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