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Victor Caravello - One of the best experts on this subject based on the ideXlab platform.

  • Total evaporative resistance of selected clothing ensembles
    2004
    Co-Authors: Victor Caravello
    Abstract:

    Abstract : With regard to heat stress, the limiting factor inherent in clothing ensembles is the total evaporative resistance. For the same work demands, clothing with higher evaporative resistance impedes the ability to cool by sweat evaporation. Knowing the evaporative resistance provides a means to compare candidate ensembles. Further, a value for evaporative resistance means that a rational method can be used to assess the heat stress exposure. Evaporative resistance of five clothing ensembles (cotton work clothes, cotton coveralls, and three coveralls of particle Barrier, Liquid Barrier and vapor Barrier properties) was determined empirically from wear tests during two study phases. For Phase 1, the metabolic rate was held constant at 160 W/sq m, and three levels of humidity (20, 50, 70% rh) were explored. Fourteen heat-acclimated participants (9 men and 5 women) completed trials for all combinations of clothing ensemble and environment. In the Phase 2 study, the humidity was held constant at 50% rh, and three levels of metabolic rate (114, 176, 250 W/sq m) were explored. Fifteen heat-acclimated participants (11 men and 4 women) completed trials for all combinations of clothing ensemble and environment. The data from both phases were analyzed separately using ANOVA. Significant differences were found among ensembles (p

  • total evaporative resistance of selected clothing ensembles
    2004
    Co-Authors: Victor Caravello
    Abstract:

    Abstract : With regard to heat stress, the limiting factor inherent in clothing ensembles is the total evaporative resistance. For the same work demands, clothing with higher evaporative resistance impedes the ability to cool by sweat evaporation. Knowing the evaporative resistance provides a means to compare candidate ensembles. Further, a value for evaporative resistance means that a rational method can be used to assess the heat stress exposure. Evaporative resistance of five clothing ensembles (cotton work clothes, cotton coveralls, and three coveralls of particle Barrier, Liquid Barrier and vapor Barrier properties) was determined empirically from wear tests during two study phases. For Phase 1, the metabolic rate was held constant at 160 W/sq m, and three levels of humidity (20, 50, 70% rh) were explored. Fourteen heat-acclimated participants (9 men and 5 women) completed trials for all combinations of clothing ensemble and environment. In the Phase 2 study, the humidity was held constant at 50% rh, and three levels of metabolic rate (114, 176, 250 W/sq m) were explored. Fifteen heat-acclimated participants (11 men and 4 women) completed trials for all combinations of clothing ensemble and environment. The data from both phases were analyzed separately using ANOVA. Significant differences were found among ensembles (p<0.0001). The vapor Barrier ensemble had the highest resistance at 0.026 kPa sq m/W. The Liquid Barrier was next at 0.018; followed by the particle Barrier and cotton coveralls at 0.016 Work clothes was 0.014 kPa sq m/W. Pair-wise comparisons adjusted for multiple comparisons were used to locate the differences among ensembles. Vapor and Liquid Barrier ensembles were found to be significantly different from other ensembles. Data from both studies support the conclusion that there are differences in evaporative resistances among selected ensembles tested.

Karsten Pruess - One of the best experts on this subject based on the ideXlab platform.

  • a design study for the isolation of the 281 3h retention basin at the savannah river site using the viscous Liquid Barrier technology
    Other Information: PBD: Nov 1996, 1996
    Co-Authors: George J Moridis, Laurence Pellerin, Larry Myer, P Persoff, J Apps, A Mcgrath, A James, Curtis M. Oldenburg, Karsten Pruess
    Abstract:

    This report is a description of the design study for a pilot-scale field demonstration of the Viscous Liquid Barrier (VLB) technology, a new subsurface containment technology for waste isolation using a new generation of Barrier Liquids. The demonstration site was Retention Basin 281-3H, a shallow catchment basin at the Savannah River Site, which is contaminated mainly by radionuclides ({sup 137}Cs, {sup 90}Sr, and {sup 238}Pu). The goals of the field demonstration were (a) to demonstrate the ability to create a continuous subsurface Barrier in order to isolate the contaminants, and (b) to demonstrate the continuity, performance, and integrity of the Barrier. The site was characterized, and preliminary hydraulic conductivity data were obtained from core samples. Based on the site characteristics and the functional requirements, a conceptual model was developed, the Barrier specifications were defined, and lance injection was selected as the emplacement method. The injection strategy for the subsurface conditions at the site was determined using numerical simulations. An appropriate variant of Colloidal Silica (CS) was selected as the Barrier Liquid based on its relative insensitivity to interactions with the site soils, and the formulation for optimum site performance was determined. A Barrier verification strategy, including hydraulic, pneumatic, tracer, and geophysical methods, was developed. A lance water injection test was conducted in order to obtain representative estimates of the hydraulic conductivity and its distribution for the design of the Barrier emplacement. The water injection test demonstrated the lack of permeable zones for CS injection, and a decision not to proceed with the Barrier emplacement was reached.

  • Lance water injection tests adjacent to the 281-3H retention basin at the Savannah River Site, Aiken, South Carolina
    1996
    Co-Authors: Barry Freifeld, Laurence Pellerin, Paul J. Cook, Larry R. Myer, George J Moridis, A James, Karsten Pruess
    Abstract:

    A pilot-scale field demonstration of waste isolation using viscous- Liquid containment Barriers has been planned for the 281-3H retention basin at the Savannah River Site, Aiken, SC. The 281-3H basin is a shallow retention/seepage basin contaminated mainly by radionuclides. The viscous-Liquid containment Barrier utilizes the permeation of Liquid grout to either entomb the contaminants within a monolithic grout structure or to isolate the waste by drastically reducing the permeability, of the soils around the plume. A clear understanding of the hydrogeologic setting of the retention basin is necessary for proper design of the viscous Liquid Barrier. To aid in the understanding of the hydrogeology of the 281-3H retention basin, and to obtain critical parameters necessary for grout injection design, a series of tests were undertaken in a region immediately adjacent to the basin. The objectives of the LWIT were: 1. To evaluate the general performance of the Lance Injection Technique for grout emplacement at the site, including the range and upper limits of injection pressures, the flow rates applicable for site conditions, as well as the mechanical forces needed for lance penetration. 2. To obtain detailed information on the injectability of the soils immediately adjacent to the H-area retention basin. 3. To identify any high permeability zones suitable for injection and evaluate their spatial distribution. 4. To perform ground penetrating radar (GPR) to gain information on the structure of the soil column and to compare the results with LWIT data. This report will focus on results pertinent to these objectives.

Elizabeth A. Mccullough - One of the best experts on this subject based on the ideXlab platform.

  • Liquid Barrier and Thermal Comfort Properties of Surgical Gowns
    Progress in Pacific Polymer Science 2, 1992
    Co-Authors: Elizabeth A. Mccullough
    Abstract:

    For many years, protective garments have been worn by surgical personnel to prevent the contamination of the patient from microorganisms. More recently, medical personnel have been concerned about being exposed to diseases from the body fluids of the patient [e.g., hepatitis B (HBV), human immunodeficiency virus (HIV), and acquired immunodeficiency syndrome (AIDS)]. The Association of Operating Room Nurses and testimony at the preliminary hearings of the Occupational Safety and Health Administration have recommended that surgical gowns repel all of the body fluids typically found in the surgical setting (1,2). Consequently, the Liquid Barrier properties of fabrics used to produce these protective garments need to be measured so that these products can be compared by hospital personnel.

George J Moridis - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of alternative designs for an injectable subsurface Barrier at the brookhaven national laboratory site long island new york
    Water Resources Research, 1999
    Co-Authors: George J Moridis, Stefan Finsterle, John Heiser
    Abstract:

    Two alternative designs for the demonstration emplacement of a viscous Liquid Barrier (VLB) at the Brookhaven National Laboratory (BNL), Long Island, New York, are investigated by means of numerical simulation. The application of the VLB technology at the BNL site involved a surface-modified colloidal silica (CS), which gels upon addition of an appropriate electrolyte. Lance injection was used for the CS Barrier emplacement. The lance injections occur in three stages: primary, secondary, and tertiary. The geometry of the Barrier is based on the wedge model. The first design is based on optimization principles and determines the parameters that maximize uniformity and minimize permeability by minimizing an appropriate objective function while meeting the design criteria. These include a maximum hydraulic conductivity of 10 27 cm/s and a minimum thickness of 1 m. The second design aims to meet the same criteria and reflects standard chemical grouting practices. The combined effects of the key design parameters (i.e., lance spacing, injection location and spacing, gel time, injection rate, and volume) on the Barrier permeability are studied. The optimization-based design is shown to have a significantly better performance than the standard engineering design. The interpenetration of adjacent CS bulbs appears to be of critical importance in meeting the Barrier specifications. The three-dimensional simulations show that the Barrier performance depends heavily on the path by which the final state is achieved. The in situ field measurements of the Barrier permeability are consistent with, and appear to validate, the model predictions.

  • a design study for the isolation of the 281 3h retention basin at the savannah river site using the viscous Liquid Barrier technology
    Other Information: PBD: Nov 1996, 1996
    Co-Authors: George J Moridis, Laurence Pellerin, Larry Myer, P Persoff, J Apps, A Mcgrath, A James, Curtis M. Oldenburg, Karsten Pruess
    Abstract:

    This report is a description of the design study for a pilot-scale field demonstration of the Viscous Liquid Barrier (VLB) technology, a new subsurface containment technology for waste isolation using a new generation of Barrier Liquids. The demonstration site was Retention Basin 281-3H, a shallow catchment basin at the Savannah River Site, which is contaminated mainly by radionuclides ({sup 137}Cs, {sup 90}Sr, and {sup 238}Pu). The goals of the field demonstration were (a) to demonstrate the ability to create a continuous subsurface Barrier in order to isolate the contaminants, and (b) to demonstrate the continuity, performance, and integrity of the Barrier. The site was characterized, and preliminary hydraulic conductivity data were obtained from core samples. Based on the site characteristics and the functional requirements, a conceptual model was developed, the Barrier specifications were defined, and lance injection was selected as the emplacement method. The injection strategy for the subsurface conditions at the site was determined using numerical simulations. An appropriate variant of Colloidal Silica (CS) was selected as the Barrier Liquid based on its relative insensitivity to interactions with the site soils, and the formulation for optimum site performance was determined. A Barrier verification strategy, including hydraulic, pneumatic, tracer, and geophysical methods, was developed. A lance water injection test was conducted in order to obtain representative estimates of the hydraulic conductivity and its distribution for the design of the Barrier emplacement. The water injection test demonstrated the lack of permeable zones for CS injection, and a decision not to proceed with the Barrier emplacement was reached.

  • Lance water injection tests adjacent to the 281-3H retention basin at the Savannah River Site, Aiken, South Carolina
    1996
    Co-Authors: Barry Freifeld, Laurence Pellerin, Paul J. Cook, Larry R. Myer, George J Moridis, A James, Karsten Pruess
    Abstract:

    A pilot-scale field demonstration of waste isolation using viscous- Liquid containment Barriers has been planned for the 281-3H retention basin at the Savannah River Site, Aiken, SC. The 281-3H basin is a shallow retention/seepage basin contaminated mainly by radionuclides. The viscous-Liquid containment Barrier utilizes the permeation of Liquid grout to either entomb the contaminants within a monolithic grout structure or to isolate the waste by drastically reducing the permeability, of the soils around the plume. A clear understanding of the hydrogeologic setting of the retention basin is necessary for proper design of the viscous Liquid Barrier. To aid in the understanding of the hydrogeology of the 281-3H retention basin, and to obtain critical parameters necessary for grout injection design, a series of tests were undertaken in a region immediately adjacent to the basin. The objectives of the LWIT were: 1. To evaluate the general performance of the Lance Injection Technique for grout emplacement at the site, including the range and upper limits of injection pressures, the flow rates applicable for site conditions, as well as the mechanical forces needed for lance penetration. 2. To obtain detailed information on the injectability of the soils immediately adjacent to the H-area retention basin. 3. To identify any high permeability zones suitable for injection and evaluate their spatial distribution. 4. To perform ground penetrating radar (GPR) to gain information on the structure of the soil column and to compare the results with LWIT data. This report will focus on results pertinent to these objectives.

Hyun Kang - One of the best experts on this subject based on the ideXlab platform.

  • An Assessment of the Effects of a Hyaluronan-Based Solution on Reduction of Postsurgical Adhesion Formation in Rats: A Comparative Study of Hyaluronan-Based Solution and Two Film Barriers
    The Journal of surgical research, 2009
    Co-Authors: Jun Seok Park, Seong Jae Cha, Beom Gyu Kim, Yoo Shin Choi, Gui Young Kwon, Hyun Kang
    Abstract:

    Background. Intra-abdominal application of antiadhesive Barriers may reduce the extent and severity of postoperative adhesions. This study was designed to compare the effectiveness of a sprayable Liquid Barrier (a mixed solution of sodium hyaluronate and carboxymethylcellulose) with two conventional sheets. Methods. Eighty male Sprague Dawley rats underwent laparotomy with subsequent multiple intestinal wall abrasions and abdominal wall injury. Afterwards, sodium hyaluronate and carboxymethylcellulose (HA– CMC) solutions were intraperitoneally sprayed or a film Barrier of either oxidized regenerated cellulose (ORC) or polylactic acid (PA) was placed under the incision. At postoperative d 21, the rats underwent relaparotomy and complete adhesiolysis. Three investigators, who were blind to the group assignment, scored the extent of adhesion formation and resected specimens for histologic examination of fibrosis and inflammation. Expression profiles of parameters as mediators (macrophages [CD68]) in cellular inflammation response were analyzed. Results. Mean adhesion scores in rats that received HA-CMC solution (7.6 ± 2.3) and ORC membrane (8.1 ± 2.2) were lower than in rats that received PA film (10.7 ± 2.5) and the control group (11.2 ± 2.6) (P < 0.05 for each comparison). In addition, there were significantly fewer adhesions located between large and small intestine in the HA-CMC solution group than in the control and each of the film Barrier groups (P < 0.05 for each comparison). Conclusions. This study suggests that both HACMC solution and ORC membrane decrease the overall incidence of postoperative adhesions. However, the mixed solution of HA-CMC appeared to be superior to ORC membrane because this sprayable solution is easy to use and suitable for site-specific adhesion prevention after multifocal bowel trauma. 2011 Elsevier