This paper uses ALIS data to compare academic performance in two subjects often viewed as relatively close substitutes for one another at A-level. The important role of GCSE achievement is confirmed for both subjects. There is evidence of strong gender effects and variation in outcomes across Examination Boards. A counterfactual exercise suggests that if the sample of Business Studies candidate...

We review the first iteration of an Alternate Reality Game (ARG) designed to engage middle school students in the interpretive process behind history and the mathematical roots of cryptography and cartography. Building from the core characteristic of ARGs as collaborative sense-making systems, we sought to integrate elements of effective cooperative learning environments, such as positive inter...

CO2 refrigerant with a high operating pressure has a large difference between the suction and discharge pressures in compressors. Because of a load increase, the high performance and high reliability of compressors are required. Compared to the scroll compressor employing the conventional refrigerant, the thrust load increases in the CO2 scroll compressor. Therefore the design of thrust bearing...

2 Discipline of Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia Abstract: The reaction of a waste refrigerant mixture of CFC-12, HCFC-22 and HFC-134a (in an argon/methane bath gas) in a dielectric barrier discharge non-thermal plasma reactor has been studied. The conversion of the major refrigerant, CFC-12, ranged from 59–76 % fo...

This paper deals with the heat exchange performance prediction of a counter flow double-tube condenser for binary natural refrigerant mixtures (propane/n-butane & propane/i-butane ). The local characteristics of the heat transfer and pressure drop are calculated using a prediction method developed by authors, and the total pressure drop, the overall heat transfer coefficient and the average hea...

Air-cooled cross flow heat exchangers are very popular in the refrigeration and air conditioning industry. The fin type, tube arrangement, flow circuitry, and many geometry parameters, are to be designed and optimized. In this paper, a generic simulation and optimization tool for the design of air-cooled condensers/evaporators is introduced. It is featured with a user-friendly interface, freedo...

In this work, an unsteady state analysis of the compression cycle of a small hermetic reciprocating compressor for domestic refrigeration was carried out. The mass and energy balances were applied to the refrigerant inside the cylinder in order to determine the mass and temperature behaviour through the compression process. A specific onedimensional model of the valves was developed to calculat...

Water-cooled chiller systems have typically been designed around entering condenser water temperatures of 85°F with a Optimization of Water Cooled Chiller – Cooling Tower Combinations The warm water leaving the chilled water coils is pumped to the evaporator of the chiller, where the unwanted heat from the building is transferred by the latent heat of vaporization of the refrigerant. The compre...