11 research outputs found

    PCM thermal insulation in buildings

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    This paper presents the results of a numerical and experimental study of phase change material (PCM) filled walls and roofs under real operational conditions to achieve passive thermal comfort. The numerical part of the study was based on a one-dimensional model for the phase change problem controlled by pure conduction. Real radiation data was used to determine the external face temperature. The numerical treatment was based upon using finite difference approximations and the ADI scheme. The results obtained were compared with held measurements. The experimental set-up consisted of a small room with movable roof and side wall. The roof was constructed in the traditional way but with the phase change material enclosed. Thermocouples were distributed across the cross section of the roof. Another roof, identical but without the PCM, was also used during comparative tests. The movable wall was also constructed as is done traditionally but with the PCM enclosed. Again, thermocouples were distributed across the wall thickness to enable measurement of the local temperatures. Another wall, identical but without the PCM, was also used during comparative tests. The PCM used in the numerical and experimental tests was composed of a mixture of two commercial grades of glycol in order to obtain the required fusion temperature range. Comparison between the simulation results and the experiments indicated good agreement. Field tests also indicated that the PCM used was adequate and that the concept was effective in maintaining the indoor temperature very close to the established comfort limits. Further economical analysis indicated that the concept could effectively help in reducing the electric energy consumption and improving the energy demand pattern. (C) 1997 by John Wiley & Sons, Ltd.21141281129

    Factors affecting pain in intravenous catheter placement: Role of depression illness

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    The aim of the study was to examine factors affecting pain during intravenous (IV) catheter placement in an emergency department. A cross-sectional, observational study was conducted at an academic emergency department. Nine hundred and twenty-five adult patients who had a 20-gauge IV catheter placed were enrolled in the study. Patients were excluded for the following conditions: more than one IV attempt, altered mental status, head trauma, lack of contact due to visual impairment, hearing or speech disorder, intoxication, distracting injury or physical abnormality at the IV site. The magnitude of pain in IV catheter placement was not related to age, sex, experience of the individual placing the IV catheter, site of IV catheter insertion and use of analgesic or antidepressant drugs (p > 0.05). Patients with a history of depression reported significantly higher pain than non-depressed patients (p = 0.001). Depressed patients reported higher severity of pain during IV catheter placement than non-depressed ones. This may influence the decision on whether or not to use local anaesthesia for catheter insertion. © 2005 Blackwell Publishing Ltd

    Analysis of factors affecting pain in intravenous catheter placement: A survey of 925 patients

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    The aim of the study was to determine some factors affecting pain during intravenous (i.v.) catheter placement in an emergency department (ED). A cross-sectional, observational study was conducted at an academic ED. Nine hundred and twenty five adult patients who had a 20 gauge i.v. catheter placed were enrolled the study. Patients were excluded for the following conditions: more than one i.v. attempt, altered mental status, head trauma, lack of contact due to visual impairment, hearing or speech disorder, intoxication, distracting injury or physical abnormality at the i.v. site. The magnitude of pain of i.v. catheter placement was not related to age, sex, experience of the individual placing the i.v. catheter, site of i.v. catheter insertion and use of analgesic or antidepressive drugs (p gt; 0.05). Patients with a history of depression reported significantly higher pain than non-depressive patients (p = 0.001). Depressive patients reported higher severity of pain during i.v. catheter placement than nondepressed ones. This may influence the decision on whether or not to use local anaesthesia for catheter insertion. © Blackwell Publishing Ltd, 2005

    Factors affecting yield and gelling properties of agar

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    Agar, a gelatinous polysaccharide in the cell wall of many red algal species, is widely used as a gelling, thickening and stabilizing agent. The commercial value of seaweed is judged by their agar content and gel quality. Seaweed materials with higher agar yield and better gelling properties are desired due to the growing demand for agar in the global market. Agar biosynthesis in seaweeds is affected by genetic variations, developmental stages and environmental conditions, while different agar extraction techniques can also affect the yield and quality of agar. In this paper, the effects of different physiological states of seaweed, abiotic and biotic factors, seaweed storage and agar extraction techniques on the agar yield and gelling characteristics, are reviewed. This information is important as a guide for marine aquaculture of potential agarophytes and the possible effects of climate change on the stock of this natural resource
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