Universality of collapsing two-dimensional self-avoiding trails

Results of a numerically exact transfer matrix calculation for the model of Interacting Self-Avoiding Trails are presented. The results lead to the conclusion that, at the collapse transition, Self-Avoiding Trails are in the same universality class as the O(n=0) model of Blote and Nienhuis (or vertex-interacting self-avoiding walk), which has thermal exponent $\nu=12/23$, contrary to previous conjectures.Comment: Final version, accepted for publication in Journal of Physics A; 9 pages; 3 figure

Basic requirements of fuel-injection nozzles for quiescent combustion chambers

This report presents test results obtained during an investigation of the performance of a single-cylinder, high-speed, compression-ignition test engine when using multiple-orifice fuel-injection valve nozzles in which the number and the direction of the orifices were varied independently

Performance of a High-Speed Compression-Ignition Engine Using Multiple Orifice Fuel Injection Nozzles

This report presents test results obtained at the Langley Memorial Aeronautical Laboratory of the National Advisory Committee for Aeronautics during an investigation to determine the relative performance of a single-cylinder, high-speed, compression-ignition engine when using fuel injection valve nozzles with different numbers, sizes, and directions of round orifices. A spring-loaded, automatic injection valve was used, centrally located at the top of a vertical disk-type combustion chamber formed between horizontally opposed inlet and exhaust valves of a 5 inch by 7 inch engine

Projecting the carbon emissions from refrigeration used in the UK food industry to 2050

The impact to food cold chain greenhouse gas emissions from changes to population, climate, equipment efficiency, f-gas phase-downs, electrical grid carbon intensity and electrification of transport refrigeration up to 2050 were predicted using a 2019 baseline from a previous study. GHG emissions were projected to reduce by 98% from 2030 to 2050. This is due to decarbonisation of the electrical grid, electrification of diesel powered transport refrigeration units (TRUs) and f-gas phase down. Population and increased ambient temperature only have a marginal effect (7.2% increase to 2050). Although GHG emissions reduce, the electrical demand on the grid is projected to increase by 9.9% from 2030 to 2040 and then remain relatively stable. This is due to increased electrical demand as two thirds of HGV diesel TRUs are converted to electric

Commercial, professional and domestic refrigeration equipment efficiency in the UK: current and future trends

In the UK food cold-chain refrigeration accounted for 28.6 TWh/a of electrical energy consumption in 2019, of which 24.4 TWh was from commercial, professional and household refrigeration. Using the most recent UK projections of energy consumption for domestic, professional and commercial refrigeration, this work found that UK Government projections for domestic refrigeration are not realistic and should be adjusted to reflect that current UK sales of domestic refrigerators have higher energy consumptions than currently assumed. To drive energy improvements in professional refrigeration will require removing the 3 worst performing classes from energy labelling. Banning open fronted supermarket cabinets and/or removing the last 3 tiers of the energy label, would bring supermarket commercial refrigeration in line with current projections, but only if it happened immediately. For other commercial refrigeration equipment (beverage coolers and ice cream freezers) a more gradual approach of removing labels is suggested to be appropriate

Self-oscillating control methods for the LCC current-output resonant converter

Abstract—A strategy for self-oscillating control of LCC current-output resonant converters, is presented, based on varying the phase-angle between the fundamental of the input voltage and current. Unlike other commonly employed control methodologies,the proposed technique is shown to provide a convenient, linear system input-output characteristic suitable for the design of regulators. The method is shown to have a similar effect as controlling the dc-link supply voltage, in terms of output-voltage/current control. The LCC converter variant is used as an application focus for demonstrating the presented techniques, with simulation and experimental measurements from a prototype converter being used to show the practical benefits. Third-order small and large-signal models are developed, and employed in the formulation of robust output-voltage and output-current control schemes. However, notably, the presented techniques are ultimately generic and readily applicable to other resonant converter variants

Design of an LCC current-output resonant converter for use as a constant current source

A methodology for the design of LCC resonant current-source converters, is presented. Unlike previous techniques, the resulting converter provides near constant steady-state output current over an extended load range when excited at the resonant frequency, through use of a self-oscillating controlle

Normalized analysis and design of LCC resonant converters

Abstract—A normalization of the LCC voltage-output resonant converter performance characteristics, in terms of the tank gain at resonance and the parallel-to-series-capacitor ratio, is presented. The resulting description is subsequently used for the derivation of a design procedure that incorporates the effects of diode losses and the finite charge/discharge time of the parallel capacitor. Unlike previously reported techniques, the resulting normalized behavior of the converter is used to identify design regions to facilitate a reduction in component electrical stresses, and the use of harmonics to transfer real power. Consideration of the use of preferred component values is also given. The underlying methodology is ultimately suitable for incorporation into a software suite for use as part of a rapid interactive design tool. Both simulation results and experimental measurements from a prototype converter are included to demonstrate the attributes of the proposed analysis and design methodologies

Extraction and utilization of space acquired physiographic data for water resources development

ERTS-1 satellite imagery was evaluated as a means of providing useful watershed physiography information. From these data physiographic parameters such as drainage basin area and shape, drainage density, stream length and sinuosity, and the percentage of a watershed occupied by major land use types were obtained in three study areas. The study areas were: (1) Southwestern Wisconsin; (2) Eastern Colorado, and (3) portions of the Middle Atlantic States. Using ERTS-1 imagery at 1:250,000 and 1:100,000 scales it was found that drainage basin area and shape and stream sinuosity were comparable (within 10%) in all study areas to physiographic measurements derived from conventional topographic maps at the same scales