Comparison of expansion valve performance

This paper compares the performance of a thermostatic expansion valve, thermoelectric expanison valve, solenoid expansion valve and a motorized type operating as part of an extensively controlled and instrumented refrigeration system. It will be shown that the solenoid expansion valve provides the best contol.     

Problems encountered when using japanese package-unit air-conditioners under United Kingdom conditions

An analysis is given of problems encountered when using air-conditioners specified for warm and wet climates in cooler and dryer ones. Suggestions are made for remedying the defects.     

Transition groups for Black freshmen: Integrated service and training.

Psychological support groups for Black freshmen were developed to assist students in the transition to a predominantly White university environment. White and Black coleaders chosen from graduate students in counselor training programs provided training workshops and supervision throughout the course of the group experience. The groups developed a behavioral and task-oriented emphasis. Implications are discussed for both the retention of minority students and the unique contribution of such programs to professional training. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bioassembled nanocircuits of Mo6S9-xIx nanowires for electrochemical immunodetection of estrone Hapten

We demonstrate a novel and highly sensitive electrochemical detection of estrone based on an immunosensor platform, composed of bioassembled nanocircuits of Mo 6S 9- x I x nanowires (MoSI NWs) covalently connected to anti-estrone antibodies. The one-step, label-free, and quantitative detection of estrone is realized by employing the [Ru(NH 3) 6] (3+/2+) redox ions to sense anti-estrone antibody and estrone interactions. The MoSI NWs/anti-estrone antibody nanocircuit architectures provide an amplification and conductive pathway for the specific electrochemical sensing of estrone hapten. A detection limit of 1.4 pg x mL (-1) was achieved in contrast to previous electrochemical techniques in which the sensitivity was limited to the nanomolar range.     

Phospholipids of marine origin. II. The rock lobster (Jasus lalandii)

The composition of rock lobster roe and hepatopancreas phospholipids was determined by chromatography on silicic acid and by an hydrolytic procedure. Rock lobster roe phospholipids were similar in composition to those of hen egg yolk except for the very low content of lysophosphatides. Rock lobster hepatopancreas phospholipids were similar in composition to hake flesh phospholipids. Fatty acids from the phospholipids and the non-phosphorylated lipids of both roe and hepatopancreas had the same average equivalent weight and unsaturation; the fatty acid composition showed a close resemblance. Large differences, however, were observed in the fatty acid composition of the phosphatidyl choline and cephalin fractions, the latter containing more of the polyunsaturated fatty acids.     

Polymer molecular weight and chain transfer during the photopolymerization of an aliphatic monoacrylate in a smectic liquid crystal

Polymer/liquid crystal (LC) composites offer a unique opportunity to study polymerizations in ordered media, specifically the potential effect mesophase order can have on polymer properties including molecular weight. To develop successful polymer/LC composites for display applications, it is important to understand the effect of mesophase order on polymer molecular weight in order to optimize the electro-optic (EO) properties of the polymer/LC composite. Polymer molecular weight may be influenced in a LC by changes in polymerization rate as LC order is modulated and by chain transfer. This work focuses on the photopolymerization of an aliphatic monoacrylate monomer, decyl acrylate (DA), both in the ordered LC phases of 8CB as well as in isotropic solutions with LC and co-solvent.When DA is polymerized using the LC as the solvent, enhanced polymerization rates and polymer molecular weights are observed in the highly ordered smectic phase compared to the less ordered nematic and isotropic phases. When conducted strictly in an isotropic environment using a co-solvent with increasing 8CB percentages, a dramatic decrease in the polymerization rate and a significant reduction of the polymer molecular weight is observed, implying degradative chain transfer to the LC. NMR results show that this chain transfer is a result of hydrogen abstraction from the liquid crystals, which leads to the reduction in the polymerization rate with increasing 8CB concentration. The most likely site of hydrogen abstraction is from the benzyl hydrogens of the alkyl chain of 8CB. This chain transfer also plays a role for polymerizations performed in the ordered phases of the LC. Chain transfer appears to be less significant when polymerizations are conducted in the smectic phase due to the anti-parallel association of the LC molecules. When polymerizations occur in the less ordered phases, chain transfer dominates leading to a large reduction in polymer molecular weight and polymerization rate.     

Replacing R22 with a hydrocarbon or hydrofluorocarbon?

Today many factors affect the fluids that are being selected for use in domestic and commercial heat pumps. These include environmental issues, system cost and efficiency and several papers have been written to promote and discredit hydrofluorocarbon against natural (hydrocarbon) fluids as the best replacement for R22. This paper attempts to resolve this issue in terms of the environment, energy efficiency and system costs for small domestic and commercial heat pumps. Copyright © 2001 John Wiley & Sons, Ltd.     

The discrepancy between heat pump field and test performance: A simulation study

A discrepancy is reported whereby laboratory measurements of the COP_h of air-to-water heat pumps yield performace data which are significantly inferior to seasonal values as measured in the field. A mechanism is proposed to account for this and example calculations show that improvements of up to 20 per cent can be expected over normal laboratory estimates.     

A controlled environment laboratory for the testing of domestic heat pumps

The construction and operation of a controlled-environment laboratory for the testing of domestic heat pumps is described. the operational range of the laboratory is - 5°C to 20°C with relative humidity up to 100%. Air-to-water heat pumps of up to 16 kW heating capacity can be tested with the present design, but modifications to allow for the testing of larger units or of air-to-air units are also described. the laboratory is stable to within 1°C and 5% relative humidity, and has a recovery time of 12 min to a perturbation of 3 kW. the test procedure for air-to-water heat pumps is described in detail and some preliminary results presented.