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Showing 1 to 20 of 24 for “"Negative temperature"”.
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Negative Temperature Programming using Microwave Gas Chromatography
… be achieved. In conventional GC, only positive temperature programming is used because the oven cools down slowly due to the great thermal mass of the oven. Short cool-down time in microwave-heating GC makes it possible to employ negative temperature programming for the separation of compounds …
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Negative temperature states of bosons in triangular and kagome lattices
… the optical triangular and kagome lattices at negative temperature, where most atoms occupy the states with the highest energy. Due to geometric frustration, the highest energy states are Bloch states at the K and K′ points for the triangular lattice and the states in the flat band for the …
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Effect Of Intake Temperature And Boost Pressure On The Auto-Ignition Of Fuels With Different Cetane Numbers And Volatilities
… is to investigate the effect of air inlet temperature and boost pressure on the auto-ignition of fuels that have different CNs and volatilities in a single cylinder diesel engine. The inlet air temperature is varied over a range of 30°C to 110°C at a constant intake pressure of 1.1 bar. The …
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Quantum simulation with an optical kagome lattice
… in the flat band of the kagome lattice using negative temperatures. In addition we report, for the first time, on the creation of a negative temperature state in a triangular lattice. This thesis additionally serves to collect and consolidate theoretical research that we can directly study …
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Bose-Hubbard physics in the kagome and triangular optical lattices at negative absolute temperature
… with three-boson superfluid order at finite temperature; for fermions, a spin liquid. I describe the design of the apparatus and some technical upgrades that were implemented. The kagome lattice is realised as an optical superlattice, where the phases of the two lattices are stabilised …
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Shock Ignition of N-Heptane With Supplemental Hydrogen
… equivalence ratios (ϕ = 0.833, 1, 1.25) over a temperature range of 700 K to 1150 K. The ignition delay time data, obtained for all heptane-hydrogen fuel combinations and fuel-air equivalence ratios, is characterized by a negative temperature coefficient region between 800 K and 1000 K. This is …
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Measurement of ignition delay time of jet fuels in shock tube for the development of the chemical kinetic mechanism
… underprediction of F-24 ignition delays in the negative-temperature-coefficient and low-temperature regimes while maintaining high-temperature performance, and identify a small subset of high- and low-temperature reactions that dominate the required adjustments. First-stage ignition delays are …
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The role of fuel in determining the high load limit of controlled auto-ignition engines
… as a function of the initial concentration and temperature was used. A parametric model of the fuel chemistry was created so that different functional dependences of the ignition delay curve could be produced through adjustment of the model parameters. Then, the ignition delay curve was …
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Biosphere-atmosphere interactions over semi-arid regions : modeling the role of mineral aerosols and irrigation in the regional climate system
… a large bias in original simulations of surface temperature is eliminated by improving surface albedo, and including mineral aerosols and irrigation. These modifications reduced other biases associated with simulated surface shortwave incident radiation, surface absorbed radiation, and surface …
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Drift Tube Ion Mobility Measurements for Thermochemistry, Kinetics and Polymerization of Cluster Ions
… → (H2O)nH+ + C3H2• exhibits an unusually steep negative temperature coefficient of k = cT(sup>63±4 (or activation energy of -32 ± 1 kcal mol-1). The behavior of the C3H3+/water system is exactly analogous to the benzene+• /water system8,9, suggesting that the mechanism, kinetics and large …
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Temperature Effects on the Behavior of Liquid Hydrogen Isotopes Inside a Spherical-Shell Inertial Confinement Fusion Target
… desired high gain. The present work studies the temperature effects on the formation of a uniform liquid hydrogen layer inside a spherical glass shell (SGS). The profile of the liquid layer is first investigated for an isothermal case. An equation suitable for describing the profile is derived by …
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On fuel selection in controlled auto-ignition engines : the link between intake conditions, chemical kinetics, and stratification
… predict when the high-load limit is reached. Temperature and fuel concentration stratification, and the degree that they can be used to relax the constraint on the highload limit, were then examined. The effectiveness of stratification was then related to the chemical kinetic behavior of …
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Evaluating Fluoride Molten Salt Thermophysical Properties with Transient Grating Spectroscopy
… addition, the data displays a curious positive temperature coefficient. Understanding of heat transfer in simple fluids suggests thermal conductivity should decrease as a function of temperature. Unaccounted-for contributions from convection and radiation may result in the observation of …
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Development of a generalised kinetic model for the combustion of hydrocarbon fuels
… for the combustion of hydrocarbons. Predicted temperature-time profiles can be obtained from detailed combustion kinetics, which can be used to derive a generalised model. If the generalised model can predict results from the detailed model it can be applied in computational fluid dynamics code …
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An Investigation Of The Autoignition Of Power Generation Gas Turbine Fuel Blends Using A Design Of Experiments Approach
… of fuel blends, setting the conditions at a temperature of 800 K and pressure of 17 atm. A further and successful attempt was made to reduce the 41-test matrix to a 21-test matrix. This was done using special mixture experimental techniques. The kinetics model was used to compare the smaller …
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Investigating the feasibility of characterising gasoline autoignition using a motored engine apparatus
… fuel and the range of interest, the so called negative temperature coefficient region. Autoignition experiments were performed in the engine and the data was analysed by the comparison of measured autoignition reactions with predicted reaction times; the predictions were calculated using the …
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Influence of moving load, structure, temperature gradient, and wheel configuration on load transfer efficiency
… The curling stresses, induced due to the temperature differentials at the top and bottom of the PCC slab can lead to higher combined stresses (loading plus curling) in pavements and can affect the load transfer efficiency at the joint. This study analyzes the effect of pavement layer …
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Ionised deposition for the structural control of carbon nickel thin films
… It was determined that upon application of a negative substrate biasing, the ion flux to the growing film remained constant, however the energy of the species increased. This resulted in a columnar structure of nickel carbide which coarsened as the bias (and therefore the energy of the ions) …
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Autoignition study of next generation aviation fuels and components
… combustion performance, especially in the low temperature regime. This study is focused on evaluating the reactivity of diverse alternative fuels and related hydrocarbon components by investigating their ignition delay times at various autoignition conditions. Complex multistage ignition …
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Electrical, Magnetic, Thermal Modeling and Analysis of a 5000A Solid-State Switch Module and Its Application as a DC Circuit Breaker
… phenomenon in the module that is caused by the negative temperature coefficient of the ETO's conduction drop. The comparative study of the electro-thermal coupling identifies a strongly-coupled thermal network that increases the stability of the thermal subsystem. The electro-thermal model is …
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