276 Matching Results

Search Results

Advanced search parameters have been applied.

Flow boiling test of GDP replacement coolants

Description: The tests were part of the CFC replacement program to identify and test alternate coolants to replace CFC-114 being used in the uranium enrichment plants at Paducah and Portsmouth. The coolants tested, C{sub 4}F{sub 10} and C{sub 4}F{sub 8}, were selected based on their compatibility with the uranium hexafluoride process gas and how well the boiling temperature and vapor pressure matched that of CFC-114. However, the heat of vaporization of both coolants is lower than that of CFC-114 requiring larger coolant mass flow than CFC-114 to remove the same amount of heat. The vapor pressure of these coolants is higher than CFC-114 within the cascade operational range, and each coolant can be used as a replacement coolant with some limitation at 3,300 hp operation. The results of the CFC-114/C{sub 4}F{sub 10} mixture tests show boiling heat transfer coefficient degraded to a minimum value with about 25% C{sub 4}F{sub 10} weight mixture in CFC-114 and the degree of degradation is about 20% from that of CFC-114 boiling heat transfer coefficient. This report consists of the final reports from Cudo Technologies, Ltd.
Date: August 1, 1995
Creator: Park, S.H.
Partner: UNT Libraries Government Documents Department

AISI/DOE Technology Roadmap Program: TRP 9732Steel Processing Properties and Their Effect on Impact Deformation of Lightweight Structures

Description: The objective of the research was to perform a comprehensive computational analysis of the effects of material and process modeling approaches on performance of Ultra Light Steel Auto Body (ULSAB) vehicle models. The research addressed numerous material related effects, impact conditions as well as analyzed the performance of the ULSAB vehicles in crashes against designs representing the current US vehicle fleet. Crash modeling simulations show a clear effect of strain-rate sensitivity on high strength steel (HSS) intensive vehicle. The influence of a strain-rate model can be an incremental sensitivity due to the increased flow stress when similar structure collapse modes are predicted. However, significant differences in crash energy management capacity can be predicted if the change in loading on members alters the predicted collapse mode of the structure. From the material substitution study it can be concluded that HSS material substitution cannot be performed on the basis of the material yield point only and that, especially for advanced HSS vehicle designs, the entire region of material plastic response has to be considered. However, the problem of modeling of the overall dynamic crush process still remains open and requires further experimental and theoretical investigation. Crash modeling simulations show a moderate effect of forming on overall crash performance. The design is the determining factor on the vehicle performance and, therefore, the results of this research cannot provide measures that can be used in a general case. However, it has been shown that for materials that have modest strain hardening, the forming effect is observable and that when more complex forming operations are used, especially in combination with rapid strain hardening materials, forming effects should be taken in the consideration in the computational crash models. crash compatibility study between ULSAB and cars of similar geometric characteristics have shown that the U LSAB design ...
Date: January 31, 2002
Creator: Simunovic, Srdan & Aramayo, Gustavo
Partner: UNT Libraries Government Documents Department

Materials Compatibility and Lubricants Research on CFC-refrigerant substitutes; Quarterly MCLR program technical progress report, 1 October 1993--31 December 1993

Description: The Materials Compatibility and Lubricants Research (MCLR) program supports critical research to accelerate the introduction of CFC and HCFC refrigerant substitutes. The MCLR program addresses refrigerant and lubricant properties and materials compatibility. The primary elements of the work include data collection and dissemination, materials compatibility testing, and methods development. The work is guided by an Advisory Committee consisting of technical experts from the refrigeration and air-conditioning industry and government agencies. The AirConditioning and Refrigeration Technology Institute, Inc., (ARTI) manages and contracts multiple research projects and a data collection and dissemination effort. Detailed results from these projects are reported in technical reports prepared by each subcontractor.
Date: January 1, 1994
Creator: Szymurski, S.R.; Hourahan, G.C. & Godwin, D.S.
Partner: UNT Libraries Government Documents Department

An evaluation of alternative cleaning methods for removing an organic contaminant from a stainless steel part

Description: As of December 1995, the manufacture of Freon, along with many other chlorofluorocarbons (CFCs), was prohibited by the Clean Air Act of 1990 (CAA). The ban of CFC solvents has forced manufacturers across the country to search for alternative metal cleaning techniques. The objective of this study was to develop a thorough, scientific based approach for resolving one specific manufacturer`s problem of removing organic contamination from a stainless steel part. This objective was accomplished with an approach that involved: (1) defining the problem, (2) identifying the process constraints, (3) researching alternate cleaning methods, (4) researching applicable government regulations, (5) performing a scientific evaluation and (6) drawing conclusions.
Date: August 1, 1996
Creator: Boyd, J.L.
Partner: UNT Libraries Government Documents Department

Thermophysical properties of HCFC alternatives. Final report, 1 April 1994--31 October 1996

Description: Numerous fluids and fluid mixtures have been identified as promising alternatives to the HCFC refrigerants, but, for many of them, reliable thermodynamic data do not exist. In particular, reliable thermodynamic properties data and models are needed to predict the performance of the new refrigerants in heating and cooling equipment and to design and optimize equipment to be reliable and energy efficient. The objective of the project is to measure, with high accuracy, selected thermodynamic properties data for one pure refrigerant and nine refrigerant blends; these data will be used to fit equations of state and other property models which can be used in equipment design. The new data will fill in gaps in the existing data and resolve problems and differences that exist in and between existing data sets. Most of the studied fluids and blends are potential replacements for HCFC-22 and/or R-502; in addition, one pure fluid and one blend are potential replacements for CFC-13 in low temperature refrigerant applications.
Date: November 1, 1996
Creator: Haynes, W.M.
Partner: UNT Libraries Government Documents Department

Fiber-matrix interfaces in ceramic composites

Description: The mechanical properties of ceramic matrix composites (CMCs) are governed by the relationships between the matrix, the interface material, and the fibers. In non-oxide matrix systems compliant pyrolytic carbon and BN have been demonstrated to be effective interface materials, allowing for absorption of mismatch stresses between fiber and matrix and offering a poorly bonded interface for crack deflection. The resulting materials have demonstrated remarkable strain/damage tolerance together with high strength. Carbon or BN, however, suffer from oxidative loss in many service environments, and thus there is a major search for oxidation resistant alternatives. This paper reviews the issues related to developing a stable and effective interface material for non-oxide matrix CMCs.
Date: December 31, 1996
Creator: Besmann, T.M.; Stinton, D.P.; Kupp, E.R.; Shanmugham, S. & Liaw, P.K.
Partner: UNT Libraries Government Documents Department

ARTI refrigerant database

Description: The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. it consolidates and facilitates.access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern.
Date: January 15, 1996
Creator: Calm, J.M.
Partner: UNT Libraries Government Documents Department

Materials used in new generation vehicles: supplies, shifts, and supporting infrastructure

Description: The Partnership for a New Generation of Vehicles (PNGV) program intends to develop new designs for automobiles that will reduce fuel consumption by two thirds but otherwise have price, comfort, safety, and other measures of performance similar to the typical automobile now on the market. PNGV vehicle designs are expected to substitute lightweight materials, such as aluminum, magnesium, carbon-reinforced polymer composites, glass-reinforced polymer composites, and ultra- light steel, for heavier materials such as steel and iron in automobile components. The target mass of a PNGV vehicle is 1,960 pounds, as compared to the average current vehicle that weights 3,240 pounds. Other changes could include the use of different ferrous alloys, engineering changes, or incorporation of advanced ceramic components. Widespread adoption of these vehicle designs would affect materials markets and require concurrent development and adoption of supporting technologies to supply the materials and to use and maintain them in automobiles. This report identifies what would be required to bring about these changes and developments in materials substitution; identifies reasons that might make these substitutions difficult to accomplish within the overall objectives and timetable of the PNGV program; and identifies any issues arising from the substitution that could prompt consideration of policies to deal with them. The analysis in this paper uses scenarios that assume the production of new generation vehicles will begin in 2007 and that their market share will increase gradually over the following 25 years. The scenarios on which the analysis is based assume a maximum substitution of each potential replacement material considered. This maximum substitution of individual materials (i.e., the amount of replacement material by weight that would be added to the baseline vehicle`s composition) is as follows: ULSAB (high strength steel), 298 lbs.; glass-reinforced composites, 653 lbs.; carbon-reinforced composites, 379 lbs.; aluminum, 926 lbs.; and magnesium, 216 ...
Date: August 1, 1997
Creator: Das, S.; Curlee, T.R. & Schexnayder, S.M.
Partner: UNT Libraries Government Documents Department

Thermophysical properties of HCFC alternatives. Quarterly report, October 1, 1994--December 31, 1994

Description: Numerous fluids and fluid mixtures have been identified as promising alternatives to the HCFC refrigerants, but, for many of them, reliable thermodynamic data do not exist. In particular, reliable thermodynamic properties data and models are needed to predict the performance of the new refrigerants in heating and cooling equipment and to design and optimize equipment to be reliable and energy efficient. The objective of this project is to measure, with high accuracy, selected thermodynamic properties data for two pure refrigerants and nine refrigerant blends; these data will be used to fit equations of state and other property models which can be used in equipment design. The new data will fill in gaps in the existing data and resolve problems and differences that exist in and between existing data sets. Most of the studied fluids and blends are potential replacements for HCFC-22 and/or R502; in addition, one pure fluid and one blend are potential replacements for CFC-13 in low temperature refrigeration applications.
Date: January 1, 1995
Creator: Haynes, W.M.
Partner: UNT Libraries Government Documents Department

High-efficiency cell structures and processes applied to photovoltaic-grade Czochralski silicon

Description: The authors performed a detailed study to examine the limiting performance available using photovoltaic-grade Cz silicon. Photovoltaic-grade silicon refers to silicon produced by the photovoltaic industry, which may differ from the silicon used in the semiconductor device industry in impurity and defect concentrations.The study included optimization of fabrication processes, development of advanced device structures, and detailed model calculations to project future performance improvements. Process and device optimization resulted in demonstration of 75-{micro}s bulk lifetimes and 17.6%-efficient large-area cells using photovoltaic-grade Cz silicon. Detailed calculations based on the material and device evaluation of the present work project efficiencies of 20% for photovoltaic-grade Cz silicon with properly optimized processing and device structures.
Date: December 1, 1996
Creator: Gee, J.M.; King, R.R. & Mitchell, K.W.
Partner: UNT Libraries Government Documents Department

Lead (Pb)-Free Solder Applications

Description: Legislative and marketing forces both abroad and in the US are causing the electronics industry to consider the use of Pb-free solders in place of traditional Sn-Pb alloys. Previous case studies have demonstrated the satisfactory manufacturability and reliability of several Pb-free compositions for printed circuit board applications. Those data, together with the results of fundamental studies on Pb-free solder materials, have indicated the general feasibility of their use in the broader range of present-day, electrical and electronic components.
Date: August 15, 2000
Partner: UNT Libraries Government Documents Department

Supercritical fluids: Reactions, materials and applications

Description: A number of important processes utilizing supercritical fluids have been either implemented or are emerging for extractions, separations and a wide range of cleaning applications. Supercritical fluids can be reasonable solvents yet share many of the advantages of gases including miscibility with other gases (i.e. hydrogen and oxygen), low viscosities and high diffusivities. Carbon dioxide has the further advantages of being nontoxic, nonflammable, inexpensive and currently unregulated. The use of compressed gases, either as liquids or supercritical fluids, as reaction media offers the opportunity to replace conventional hazardous solvents and also to optimize and potentially control the effect of solvent on chemical and material processing. The last several years has seen a significant growth in advances in chemical synthesis, catalytic transformations and materials synthesis and processing. The authors report on results from an exploratory program at Los Alamos National Laboratory aimed at investigating the use of dense phase fluids, particularly carbon dioxide, as reaction media for homogeneous, heterogeneous and phase-separable catalytic reactions in an effort to develop new, environmentally-friendly methods for chemical synthesis and processing. This approach offers the possibility of opening up substantially different chemical pathways, increasing selectivity at higher reaction rates, facilitating downstream separations and mitigating the need for hazardous solvents. Developing and understanding chemical and catalytic transformations in carbon dioxide could lead to greener chemistry at three levels: (1) Solvent replacement; (2) Better chemistry (e.g. higher reactivity, selectivity, less energy consumption); and (3) New chemistry (e.g. novel separations, use of COP{sub 2} as a C-1 source).
Date: April 9, 1999
Creator: Tumas, W.; Jacobson, G.B.; Josephsohn, N.S. & Brown, G.H.
Partner: UNT Libraries Government Documents Department

Evaluation of the Super Efficient Refrigerator Program (SERP) in the Bonneville Power Administration service territory

Description: The Super Efficient Refrigerator Program (SERP) is a collaborative utility program intended to transform the market for energy-efficient and environmentally friendly refrigerators. it is one of the first examples of large-scale {open_quotes}market transformation{close_quotes} energy efficiency program. This report documents the evaluation of SERP ({open_quotes}the Program{close_quotes}) in the Bonneville Power Administration`s (Bonneville`s) service territory. Pacific Northwest National Laboratory (PNNL) conducted this evaluation for Bonneville. This study includes the process evaluation, preliminary impact evaluation, and market transformation assessment. It is based on site visits and interviews with refrigerator dealers and manufacturers, industry data, and Bonneville information. Results from this study are compared with those from a parallel study that examines the Program across the 24 participating utilities.
Date: June 1, 1996
Creator: Lee, A.D. & Conger, R.L.
Partner: UNT Libraries Government Documents Department

Evaluation on the use of cerium in the NBL Titrimetric Method

Description: An alternative to potassium dichromate as titrant in the New Brunswick Laboratory Titrimetric Method for uranium analysis was sought since chromium in the waste makes disposal difficult. Substitution of a ceric-based titrant was statistically evaluated. Analysis of the data indicated statistically equivalent precisions for the two methods, but a significant overall bias of +0.035% for the ceric titrant procedure. The cause of the bias was investigated, alterations to the procedure were made, and a second statistical study was performed. This second study revealed no statistically significant bias, nor any analyst-to-analyst variation in the ceric titration procedure. A statistically significant day-to-day variation was detected, but this was physically small (0.01 5%) and was only detected because of the within-day precision of the method. The added mean and standard deviation of the %RD for a single measurement was found to be 0.031%. A comparison with quality control blind dichromate titration data again indicated similar overall precision. Effects of ten elements on the ceric titration`s performance was determined. Co, Ti, Cu, Ni, Na, Mg, Gd, Zn, Cd, and Cr in previous work at NBL these impurities did not interfere with the potassium dichromate titrant. This study indicated similar results for the ceric titrant, with the exception of Ti. All the elements (excluding Ti and Cr), caused no statistically significant bias in uranium measurements at levels of 10 mg impurity per 20-40 mg uranium. The presence of Ti was found to cause a bias of {minus}0.05%; this is attributed to the presence of sulfate ions, resulting in precipitation of titanium sulfate and occlusion of uranium. A negative bias of 0.012% was also statistically observed in the samples containing chromium impurities.
Date: March 1, 1995
Creator: Zebrowski, J.P.; Orlowicz, G.J.; Johnson, K.D.; Smith, M.M. & Soriano, M.D.
Partner: UNT Libraries Government Documents Department

Replacing Chemicals in Recycle Mills with Mechanical Alternatives. Quarterly progress report covering period October 1, 1999 to December 31, 1999

Description: The objective of this project is to explore potential applications of underwater pulsed power technology to the paper industry. These included fiber refining, disinfection, stickies dispersion, and stickies control. In pulsed power a spark is discharged underwater. Present commercial applications of the technology include the detonation of land mines, zebra mussel control, and water disinfection. In preliminary work the authors have found that stickies are rapidly dispersed under the influence of pulsed power. The purpose of this project is to explore other applications of the technology in the recycle paper industry, especially in applications where the technology can replace potentially expensive chemical use. The authors have found that sparking improves the screenability of stickies in the presence of pulp. Sparking is also able to detackify pitch coated on metal surfaces. This is potentially a major finding since it extends the range of the application from recycle to virgin mills. They need to determine if the effect also occurs for pitch particles suspended in whitewater. Some stickies such as Robond, a PSA used in the paint industry, are relatively unaffected by spark treatment. They find that this polymer is oxidized to a lower extent. A sparker unit has been purchased and installed at IPST. A licensing agreement with Sparktec Environmental, Stoney Creek, Canada, the manufacturer of the device, has been negotiated. It was found that sparking improves the screenability of stickies in the presence of pulp. Sparking is also able to detackify pitch coated on metal surfaces.
Date: January 13, 2000
Creator: Banerjee, Sujit
Partner: UNT Libraries Government Documents Department

Probing the structure of metal-substituted molecular sieves by solid-state NMR

Description: Paramagnetic metal ions exert large influences on the NMR spectra of neighboring nuclei. The authors are using these effects to probe metal sites in zeolites and AlPO{sub 4} molecular sieves. In particular, they are studying [Co]-AlPO{sub 4}-5 because similar cobalt substituted AlPO{sub 4} sieves are reported in the literature. They have extended that work to probe the titanium zeolite TS-1 by comparing spectra of normal TS-1 to samples where the titanium has been reduced to the paramagnetic Ti{sup 3+}. This promises to be a useful technique for determining framework substitution in many zeolite systems.
Date: July 1998
Creator: Labouriau, A.; Crawford, S.N.; Ott, K. & Earl, W.L.
Partner: UNT Libraries Government Documents Department

Automated spray cleaning using flammable solvents in a glovebox

Description: The phase-out of the ozone-depleting solvents has forced industry to look to solvents such as alcohol, terpenes and other flammable solvents to perform the critical cleaning processes. These solvents are not as efficient as the ozone-depleting solvents in terms of soil loading, cleaning time and drying when used in standard cleaning processes such as manual sprays or ultrasonic baths. They also require special equipment designs to meet part cleaning specifications and operator safety requirements. This paper describes a cleaning system that incorporates the automated spraying of flammable solvents to effectively perform precision cleaning processes. Key to the project`s success was the development of software that controls the robotic system and automatically generates robotic cleaning paths from three dimensional CAD models of the items to be cleaned.
Date: May 1, 1998
Creator: Garcia, P. & Meirans, L.
Partner: UNT Libraries Government Documents Department

The greening of PCB analytical methods

Description: Green chemistry incorporates waste minimization, pollution prevention and solvent substitution. The primary focus of green chemistry over the past decade has been within the chemical industry; adoption by routine environmental laboratories has been slow because regulatory standard methods must be followed. A related paradigm, microscale chemistry has gained acceptance in undergraduate teaching laboratories, but has not been broadly applied to routine environmental analytical chemistry. We are developing green and microscale techniques for routine polychlorinated biphenyl (PCB) analyses as an example of the overall potential within the environmental analytical community. Initial work has focused on adaptation of commonly used routine EPA methods for soils and oils. Results of our method development and validation demonstrate that: (1) Solvent substitution can achieve comparable results and eliminate environmentally less-desirable solvents, (2) Microscale extractions can cut the scale of the analysis by at least a factor of ten, (3) We can better match the amount of sample used with the amount needed for the GC determination step, (4) The volume of waste generated can be cut by at least a factor of ten, and (5) Costs are reduced significantly in apparatus, reagent consumption, and labor.
Date: December 1, 1995
Creator: Erickson, M.D.; Alvarado, J.S. & Aldstadt, J.H.
Partner: UNT Libraries Government Documents Department

Evaluation of HFC-245ca for commercial use in low pressure chillers. Final report, Volume II: Chiller test data

Description: The data presented here were taken under Trane Laboratory Test Order 23127 between May and October 1995. The chiller was a 200 nominal ton three stage direct drive centrifugal chiller with two economizers. Three sets of impellers, three refrigerants and two oils were tested in the chiller according to the following matrix. Trane 22 is a mineral oil and Solest 68 is a polyolester oil. Runs 1 through 6 were to optimize the refrigerant charge using CFC-11. This was determined to be 360 lbm (163.3 Kg) and this value was used for all three refrigerants. The chiller takes a charge of six gallons of oil (22.7 liters). These data which follow are divided into Large Impeller, Medium Impeller and Small Impeller sets further subdivided by Imperial and Metric presentation. The data were taken in Imperial Units. These data are presented in four-page sets. Page 1 shows the reduced chiller test data. Page 2 shows some supporting calculations by curve fit, such as motor efficiency and motor speed. Pages 3 and 4 show the raw data as delivered by the laboratory. All following four-page sets are repetition of the form but for successive test runs.
Date: March 1, 1996
Creator: Keuper, E.F.
Partner: UNT Libraries Government Documents Department

Air compliance through pollution prevention at Air Force Materiel Command facilities.

Description: Options for air compliance through pollution prevention (P2) have been identified at 14 facilities of the US Air Force Materiel Command, ranging from depots with significant light industrial activity to laboratories. Previous P2 efforts concentrated on reducing hazardous and solid wastes, with any reduction in air impacts generally being a collateral benefit. This work focused on reducing air emissions and air compliance vulnerabilities. P2 options were identified in three stages. First, potentially applicable P2 options were identified from Internet and published information. Attention was given to identifying the types of sources to which an option could be applied, the option's state of development, and constraints that could limit its application. Traditional P2 options involving technology or equipment changes and material substitution were considered. In addition, newer approaches based on administrative ''controls'' were considered. These included inserting P2 into operating permits in exchange for administrative relief, privatization, derating boilers, and reducing an installation's potential to emit and compliance vulnerability by separating sources not under the Air Force's ''common control.'' Next, criteria and toxic emissions inventories by source category were prepared from inventory data supplied by facilities. The major problems at this stage were differences in the levels of detail provided by facilities and in the categories used by different installations. Emitting categories were matched to P2 option categories to identify candidate options. Candidates were screened to account for local regulations and technical information about sources in the inventories. When possible, emission reductions were estimated to help facility personnel prioritize options. Some options identified are being actively pursued by facilities to determine their site-specific feasibility. Although much work has been done to implement material substitution programs, this work indicates that different priorities and additional opportunities might result from using air emissions and compliance vulnerability as driving metrics.
Date: March 19, 1999
Creator: Kolpa, R.; Ryckman, S.J. Jr. & Smith, A.E.
Partner: UNT Libraries Government Documents Department

Hazardous solvent substitution

Description: Eliminating hazardous solvents is good for the environment, worker safety, and the bottom line. However, even though we are motivated to find replacements, the big question is `What can we use as replacements for hazardous solvents?`You, too, can find replacements for your hazardous solvents. All you have to do is search for them. Search through the vendor literature of hundreds of companies with thousands of products. Ponder the associated material safety data sheets, assuming of course that you can obtain them and, having obtained them, that you can read them. You will want to search the trade magazines and other sources for product reviews. You will want to talk to users about how well the product actually works. You may also want to check US Environmental Protection Agency (EPA) and other government reports for toxicity and other safety information. And, of course, you will want to compare the product`s constituent chemicals with the many hazardous constituency lists to ensure the safe and legal use of the product in your workplace.
Date: November 1, 1995
Creator: Twitchell, K.E.
Partner: UNT Libraries Government Documents Department