The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
Erik Bardy - One of the best experts on this subject based on the ideXlab platform.
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Predicting the Thermal Conductivity of Foam Neoprene at Elevated Ambient Pressure
Journal of Thermal Science and Engineering Applications, 2010Co-Authors: Erik Bardy, Joseph C MollendorfAbstract:The purpose of this paper is to present a correlation for predicting the thermal conductivity of foam Neoprene at varying ambient pressure. In a previous study, the authors used well-known upper and lower bounds to develop the form of a semi-empirical correlation for the thermal conductivity of foam Neoprene as a function of increasing ambient pressure. The correlation was in terms of three constants, which were determined by performing a nonlinear regression on experimentally measured thermal conductivity values of foam Neoprene insulation at varying ambient pressure. In this present paper, we show that the three correlation constants can, alternately, be determined by using values of the constituent thermal conductivities (e.g., air and rubber) and the effective thermal conductivity at one pressure point only (reference pressure). Values predicted using the correlation were compared with previously measured values of the effective thermal conductivity of foam Neoprene insulation under increased ambient pressure, up to 1.18 MPa. It was found that there was a maximum difference of approximately 14% between the predicted and measured values. It was also found that the accuracy of the correlation did not depend strongly on the reference pressure used. It was therefore concluded that the effective thermal conductivity of foam Neoprene, as a function of increasing ambient pressure, can be predicted if the constituent thermal conductivities are known (air and rubber), as well as the effective thermal conductivity at one reference pressure.
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A comparison of the thermal resistance of a foam Neoprene wetsuit to a wetsuit fabricated from aerogel-syntactic foam hybrid insulation
Journal of Physics D: Applied Physics, 2006Co-Authors: Erik BardyAbstract:The purpose of this study was to compare the thermal resistance of a\nwetsuit fabricated from aerogel-syntactic foam hybrid insulation\ndeveloped by Bardy et al {[}1] to a foam Neoprene wetsuit. The thermal\nresistance of the hybrid wetsuit and a foam Neoprene wetsuit was\nmeasured on a human test subject in water at 0.25 MPa (15.25 msw) of\nhyperbaric pressure. Measurements showed that although certain body\nregions of the hybrid wetsuit had a higher thermal resistance than foam\nNeoprene, the overall thermal resistance of the hybrid wetsuit was 41%\nless than a foam Neoprene wetsuit, and 51-88% less than predicted\nvalues. This was postulated, based on sample testing in water, to be\ndue, in part, to increased heat flow through the hybrid insulation from\nwater filled surface depressions at higher pressures. Other factors may\nhave included water flow over the skin and the presence of thermal\nbridges in the insulation. Due to a smooth surface and tighter fit, the\nmeasured thermal resistance of the foam Neoprene wetsuit was within\n2-23% of the values predicted using data from Bardy et al {[} 2]. It\nwas concluded that unless the surface depressions can be eliminated,\nand alternative methods for a tighter fit achieved, foam Neoprene\nprovides more thermal protection.
D.k. Tripathy - One of the best experts on this subject based on the ideXlab platform.
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Studies on a self-crosslinking blend system based on Neoprene and polyacrylamide: 1. Mechanism and characterization
Polymer, 1993Co-Authors: S Kole, D.k. TripathyAbstract:Abstract The Neoprene and polyacrylamide system was studied at various blend ratios. Infra-red studies indicate the reactive nature of Neoprene, polyacrylamide and their blends. Inter-crosslinking between Neoprene and polyacrylamide segments occurs by chemical reaction through the imide groups formed from polyacrylamide and the halogen atoms of Neoprene. Studies with a differential scanning calorimeter and a dynamic mechanical analyser clearly indicate the apparent incompatible nature of the blend and show it to be a three-phase system. The third phase is a compatibilized interfacial zone of inter-crosslinked material. Preferential etching of the phases with solvents is possible. A scanning electron microscopy study also confirmed the multiple-phase structure of the cured blends.
John Frim - One of the best experts on this subject based on the ideXlab platform.
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EVALUATION OF TWO THERMO-METAL NeopreneS
1994Co-Authors: Michael B. Ducharme, John FrimAbstract:The reported values of Rd are averages of resistances measured for two heat fluxes (-80 and 250 for every Neoprene material. A constant pressure of 60 pounds was applied on the samples during the testing to assure good contact with the copper plates of the Rapid-k. The pressure was not sufficient to create noticeable compression of the Neoprenes. The objective of measuring Rw was to investigate the effect of pressure and wetness on the thermal performance of the Neoprene materials (wet tests). The tests were conducted in a hyperbaric chamber partially filled with stirred water maintained at 5°C in which a custom made temperature conrrolled water bath was partially immersed and maintained at 35°C to allow a transfer of heat through the test material fxed to the bottom of the bath. The Neoprene test sample was sandwiched between the bottom part of the bath (acting as a hot plate) and the "test bed" (acting as a cold plate). The test bed, in contact with the water at 5°C consisted of a 1 cm thick aluminium plate (40 x 40 cm) and a 0.6 cm Teflon@ bed (30 x 30 cm) on which were fixed four recalibrated heat flux transducers (HITS; model HA13-18-10-P(C), Thermonetics Corporation, San Diego, CA). Three calibrated thermocouples (AWG 40) were futed on the upper face of the Neoprene sample and three on the lower face. The thermal resistances of the Neoprene samples were measured using the same formula as for the dry tests. The heat flux used for the measurement of Rw varied with the depth of the dives due to changes in the thickness of the Neoprene samples with pressure (-150 at 100 m). All data reported were collected at thermal steady state which was considered established when the R values changed less than 1% over a 20-min period. at 0 m to -500
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Insulative Properties of Two Thermo-Metal Neoprenes
1993Co-Authors: Michael B. Ducharme, John FrimAbstract:Abstract : The objective of the present study was to compare the thermal resistance of two thermo-metal Neoprenes (titanium and stainless steel coated) to the current Canadian Forces Arctic diving suit Neoprene (CF-N) in dry and wet environment. The test in the dry environment were conducted using a Rapid-k thermal conductivity instrument, and in the wet environment using a custom-made apparatus. The dry tests were conducted at 1 atmosphere in the laboratory, and the wet tests were done in a hyperbaric water chamber maintained at 5 deg C and at depths of 0, 10, 25, 50, and 100 m. Pre and post-dive tests were performed on the same samples to investigate the effects of two dives on the thermal resistance of the Neoprenes. It was found that the thermal insulation of the two thermo-metal Neoprenes tested was significantly higher than that of the CF-N in both the dry and the wet environments. The best thermo-metal Neoprene, the stainless steel coated Neoprene, averaged an improvement of 53% in the dry and 60% in the wet environment (ranging from 70% at 0 m to 34% at 100 m). The insulative properties of the thermo-metal Neoprenes were affected, however, by the dives, decreasing by about 12% after two dives. It was concluded that the stainless steel thermo-metal Neoprene could be a potential alternative to the current CF Arctic diving suit Neoprene but further testing is needed on the long term effects of dives and aging on the insulative properties of the material. Thermal resistance, Diving suit, Wet suit, Reflective material, Radiant heat.
David Ring - One of the best experts on this subject based on the ideXlab platform.
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a prospective randomized comparison of Neoprene vs thermoplast hand based thumb spica splinting for trapeziometacarpal arthrosis
Osteoarthritis and Cartilage, 2013Co-Authors: Stephanie J E Becker, Arjan G J Bot, Suzanne E Curley, Jesse B Jupiter, David RingAbstract:Summary Objective In patients with trapeziometacarpal arthrosis, we tested the hypothesis that there is no difference in arm-specific disability 5–15 weeks after prescription of a pre-fabricated Neoprene or a custom-made thermoplast hand-based thumb spica splint with the metacarpophalangeal joint included and the first interphalangeal joint free. Method One hundred nineteen patients with a diagnosis of trapeziometacarpal arthrosis were prospectively randomized to wear either a Neoprene or a thermoplast hand-based thumb spica splint. At enrollment, patients completed a set of validated questionnaires. An average of 9 weeks later, patients returned for a second visit. Bivariable analyses assessed factors associated with disability, pain and satisfaction. Analysis was by intention-to-treat. Results Sixty-two patients (32 with a Neoprene and 30 with a thermoplast splint) completed the study, 51 patients (43%) did not return for the second visit, and six did not complete the protocol for other reasons. Non-completers were significantly younger than completers ( P P = 0.048), but there were no detectable differences in Disabilities of the Arm, Shoulder and Hand (DASH), change in DASH, pain, satisfaction, pinch or grip strength between the two splint types in our sample. Conclusion When compared to custom-made thermoplast splints, pre-fabricated Neoprene hand-based thumb spica splints are, on average, more comfortable, less expensive, and as effective in treating trapeziometacarpal arthrosis. This trial was registered at Clinicaltrials.gov (NCT00438763).
Chao Yu - One of the best experts on this subject based on the ideXlab platform.
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Service Life Prediction for the Neoprene Used in Seawater
Advanced Materials Research, 2013Co-Authors: Chao YuAbstract:The heat seawater method was designed and the accelerated aging tests of the Neoprene were carried in laboratory. The toughness and strength of the Neoprene in aging time was investigated. The rule of toughness and strength and aging time was studied. The service life prediction functions of the Neoprene were established and service life at 25°C was estimated based on the index of toughness and strength. It is concluded that toughness and strength of the Neoprene decreases in exponential form with aging time, and the service life of the Neoprene used in sea water at 25°C is 29.5 years.
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Service Life Prediction for the Neoprene Based on Tearing Strength
Advanced Materials Research, 2011Co-Authors: Chao YuAbstract:The degradation of Neoprene often occurs as a slow and gradual process and it is cannot be used abruptly. In order to keep the safety of equipments and people, it is important to consider the development of such process to correctly estimate its service life. The heat seawater method was designed and the accelerated aging tests of the Neoprene were carried in laboratory. The tearing strength of the Neoprene in aging time was investigated. The rule of tearing strength and aging time was studied. The service life prediction function of the Neoprene was established and service life at 25°C was estimated based on the index of tearing strength. The result shows that tearing strength of the Neoprene decreases in exponential form with aging time, and the service life of the Neoprene used in sea water at 25°C is 29.79 years.
