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Cooling Unit (cooling + unit)
Selected AbstractsRapid Cooling Aborts Seizure-Like Activity in Rodent Hippocampal-Entorhinal SlicesEPILEPSIA, Issue 10 2000Matthew W. Hill Summary Purpose: As a preliminary step in the development of an implantable Peltier device to abort focal neocortical seizures in vivo, we have examined the effect of rapid cooling on seizures in rodent hippocampal-entorhinal slices. Methods: Seizure-like discharges were induced by exposing the slices to extracellular saline containing 4-aminopyridine (50 ,mol/L). Results: When we manually activated a Peltier device that was in direct contact with the slice, seizures terminated within seconds of the onset of cooling, sometimes preceding a detectable decrease in temperature measured near the top of the slice. However, activation of the Peltier device did not stop seizures when slices were no longer in direct physical contact with the device, indicating that this was not a field effect. When cooling was shut off and temperature returned to 33oC, bursting some-times returned, but a longer-term suppressive effect on seizure activity could be observed. In two of our experiments, a custom computer program automatically detected seizure discharges and triggered a transistor-transistor logic pulse to activate the Peltier device. In these experiments, the Peltier device automatically terminated the slice bursting in less than 4 seconds. When the Peltier device was placed in contact with the normal, exposed cortex of a newborn pig, we found that the cortical temperature decreased rapidly from 36oC to as low as 26oC at a depth of 1.7 mm below the cooling unit. Conclusions: These experiments show that local cooling may rapidly terminate focal paroxysmal discharges and might be adapted for clinical practice. [source] Adhesion and detachment characteristics of a TBAB hydrate solid on a heat transfer surface (Effect of concentration of TBAB solutions)HEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 6 2009Tadafumi Daitoku Abstract In air-conditioning systems, it is desirable that the liquid,solid phase change temperature of a cool energy storage material be approximately 10°C, with respect to improving the coefficient of performance (COP). Moreover, a thermal storage material that forms slurry can realize a large heat capacity of the working fluids. A solid that adheres to the heat transfer surface forms a thermal resistance layer and significantly reduces the rate of cold storage; therefore, it is important to avoid the adhesion of a thick solid layer on the surface so as to realize efficient energy storage. Considering a harvest type cooling unit, the force required for removal of the solid phase from the heat transfer surface was investigated. Tetra-n-butylammonium bromide (TBAB) clathrate hydrate was used as a cold storage material and the effect of the TBAB solution concentration on the scraping force required to detach the adhered TBAB hydrate solid from the heat transfer surface was experimentally examined. The TBAB hydrate solids were broadly categorized into two types, and the scraping force required for removal of these two types of TBAB hydrate solid was different. The scraping force required for removal of the solid increased due to the effect of increasing the concentration of the TBAB solution. © 2009 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20254 [source] An effect of scraper shapes on detachment of solid adhered to cooling surface for formation of clathrate hydrate slurryHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 8 2007Tadafumi Daitoku Abstract In air-conditioning systems, it is desirable that the liquid, solid phase change temperature of a cool energy storage material is approximately 10°C from the perspective of improving the coefficient of performance (COP). Moreover, a thermal storage material that forms slurry can realize large heat capacity of working fluids. Since the solid that adheres to the heat transfer surface forms a thermal resistance layer and remarkably reduces the rate of cold storage, it is important to avoid the adhesion of a thick solid layer on the surface so as to realize efficient energy storage. Considering a harvest type cooling unit, the force required for removing the solid phase from the heat transfer surface was studied. Tetra-n-butylammonium bromide (TBAB) clathrate hydrate was used as a cold storage material. The effect of the scraper shapes on the scraping force for detachment of the adhered solid of TBAB hydrate to the heat transfer surface was examined experimentally. The TBAB hydrate solids were categorized broadly into two kinds of solids. The scraping force of the TBAB hydrate solid on the heat transfer surface was different for the two kinds of the TBAB hydrate solids. And the scraping force of the TBAB hydrate solid formed after scraping was improved by the modifying the scraper shape. © 2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(8): 489, 500, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20179 [source] Operational results of an intermittent absorption cooling unitINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 9 2002Ali R. El-GhalbanArticle first published online: 15 JUL 200 Abstract The concept of solar cooling is appealing because the cooling load is in phase with the intensity of solar energy. Many system arrangements or cycles are employed to achieve solar cooling, such as Absorption, desiccant or Rankine-vapour compression systems. The technical feasibility of driving an absorption-cooling unit by a low-temperature heat source (such as solar energy using a simple flat-plate collector) for air-conditioning applications is investigated in this work. This study aims to design and construct a prototype for an intermittent absorption refrigeration system and to examine its implementation. The operating characteristics of the considered unit are extensively investigated. In order to accomplish this strategy, the prototype was integrated in a test rig designed for this purpose and equipped with the necessary measuring instruments to determine the required operating criteria of the unit. The energy added or extracted to or from the different unit components is calculated and the system performance is analysed. The C.O.P of the unit is found to be 19% which is 2% lower than the designed value, which could be regarded as an encouraging result for more studies in this field. Copyright © 2002 John Wiley & Sons, Ltd. [source] Randomized Double-blind Placebo Controlled Crossover Study of Acetaminophen, Ibuprofen, Acetaminophen/Hydrocodone, and Placebo for the Relief of Pain From a Standard Painful StimulusACADEMIC EMERGENCY MEDICINE, Issue 9 2009James R. Miner MD Abstract Objectives:, The objective was to compare subjects' change in perceived acute pain from an identical painful stimulus after receiving three separate, commonly used pain medications and placebo. Methods:, This was an institutional review board,approved, randomized, double-blind crossover study of healthy human volunteers. Subjects received 1000 mg of acetaminophen, 800 mg of ibuprofen, the combination of 650 mg of acetaminophen with 10 mg of hydrocodone, or placebo (800 mg of lactose) in a randomized order over four separate occasions each 1 week apart. Prior to receiving the drug on each study day, subjects placed their nondominant hand in a bath of 0°C water for 45 seconds. The bath was divided into two sections; the larger was the reservoir of cooled water monitored at 0°C, and the other half was filled from constant overflow. Water drained from the overflow section into the cooling unit and was then pumped up into the base of the reservoir through a diffusion grid. Subjects completed a 100-mm visual analog scale (VAS) representing perceived pain during the exposure. The cold water exposure and VAS were repeated 1 hour after receiving the study drug, and then subjects were observed for side effects for 4 hours. Data were compared using descriptive statistics, 95% confidence intervals (CIs), and repeated-measures analysis of variance (ANOVA). Results:, Twenty-five subjects were enrolled. The mean VAS preexposure was 56.9 mm (±15.1 mm; range = 5 to 92 mm). The mean decrease in VAS after receiving the study drug for acetaminophen was 10.2% (95% CI = ,1.4 to 20.4), for ibuprofen was ,6.6% (95% CI = ,16.5 to 3.20), for acetaminophen/hydrocodone was 9.5% (95% CI = 1.4 to 20.4), and for placebo was ,6.9% (95% CI = ,15.2 to 1.4). The range in change in pain scores for all agents was ,91.3% to 57.6%. Mild side effects (nausea, dizziness, or somnolence) were reported in 11 subjects (44%) after receiving acetaminophen/hydrocodone; no other side effects were reported. Conclusions:, There was a wide range of changes in pain scores from this identical painful stimulus after receiving the study medications. Acetaminophen and acetaminophen/hydrocodone resulted in a similar decrease in pain (10.2 and 9.5%), while ibuprofen and placebo had a similar lack of effect (,6.6 and ,6.9%). Forty-four percent of subjects receiving acetaminophen/hydrocodone reported mild side effects; no other side effects were seen. In this noninflammatory pain model, the VAS is not able to distinguish differences in pain relief between acetaminophen and acetaminophen/hydrocodone or ibuprofen and placebo. [source] Surface Cooling for Rapid Induction of Mild Hypothermia After Cardiac Arrest: Design Determines EfficacyACADEMIC EMERGENCY MEDICINE, Issue 4 2010Thomas Uray MD Abstract Objectives:, Recently, a novel cooling pad was developed for rapid induction of mild hypothermia after cardiac arrest. The aim of this study was to evaluate the cooling efficacy of three different pad designs for in-hospital cooling. Methods:, Included in this prospective interventional study were patients with esophageal temperature (Tes) > 34°C on admission. The cooling pad consists of multiple cooling units, filled with a combination of graphite and water, which is precooled to ,18°C (design A) or to ,9°C (designs B and C) before use. The designs of the cooling pad differed in number, shape, and thickness of the cooling units, with weights of 9.7 kg (design A), 5.3 kg (design B), and 6.2 kg (design C). All three designs were tested in sequential order and were changed according to the results found in the previous trial. Cooling was started after admission until Tes = 34°C, when the cooling pad was removed. The target temperature of Tes = 32,34°C was maintained for 24 hours. Data are presented as medians and interquartile ranges (IQRs = 25%,75%) or proportions. Results:, Cooling rates were 3.4°C/hour (IQR = 2.5,3.7) with design A (n = 12), 2.8°C/hour (IQR = 1.6,3.3) with design B (n = 7), and 2.9°C/hour (IQR = 1.9,3.6) with design C (n = 10; p = 0.5). To reach 34°C, the cooling pad had to be exchanged with a new one due to melting and therefore depleting cooling capacity in three patients with design A, in five patients with design B, and in no patient with design C (p = 0.004). Conclusions:, With adequate design and storage temperature, the cooling pad proved to be efficient for rapid in-hospital cooling of patients resuscitated from cardiac arrest. ACADEMIC EMERGENCY MEDICINE 2010; 17:360,367 © 2010 by the Society for Academic Emergency Medicine [source] ARCHAEOMAGNETIC FIELD INTENSITY DURING THE ROMAN PERIOD AT SIWA AND BAHRYN OASIS, EGYPT: IMPLICATIONS FOR THE FIDELITY OF EGYPTIAN ARCHAEOMAGNETIC DATAARCHAEOMETRY, Issue 3 2010R. LEONHARDT A preliminary survey was conducted in Siwa and Bahryn Oasis to test the possible influence of various rock magnetic and experimental constraints on the fidelity of the Egyptian archaeomagnetic field record. Five potsherds from the Roman era, which lasted from 1981 bp to 1555 bp, have been investigated. Archaeologists dated the localities to ,1620 bp. Ten ceramic specimens, two of each potsherd, were subjected to archaeointensity determination, including tests for domain state effects, magnetic anisotropy and magnetic cooling rate dependency. Six successful archaeointensity determinations are obtained from three individual cooling units, revealing an average field value of 37.7 ,T for the late Roman period in Siwa and Bahryn oasis, which is comparable to the present-day field strength. The error propagation of the individual uncertainties related to all applied experimental techniques results in a maximum uncertainty estimate of 4.4 ,T. The obtained field value is significantly smaller than early results and slightly smaller than some more recent determinations of the field intensity in Egypt. The difference is attributed to a combined effect of alteration, magnetic anisotropy and magnetic cooling rate dependencies. Along with other high-quality data from the south-east Mediterranean, our data suggest a field intensity minimum during the Egyptian Roman era. [source] | |||||||||||||