895 Matching Results

Search Results

Advanced search parameters have been applied.

Assessing the operational life of flexible printed boards intended for continuous flexing applications : a case study.

Description: Through the vehicle of a case study, this paper describes in detail how the guidance found in the suite of IPC (Association Connecting Electronics Industries) publications can be applied to develop a high level of design assurance that flexible printed boards intended for continuous flexing applications will satisfy specified lifetime requirements.
Date: January 1, 2011
Creator: Beck, David Franklin
Partner: UNT Libraries Government Documents Department

Report of the Workshop on Petascale Systems Integration for LargeScale Facilities

Description: There are significant issues regarding Large Scale System integration that are not being addressed in other forums such as current research portfolios or vendor user groups. Unfortunately, the issues in the area of large-scale system integration often fall into a netherworld; not research, not facilities, not procurement, not operations, not user services. Taken together, these issues along with the impact of sub-optimal integration technology means the time required to deploy, integrate and stabilize large scale system may consume up to 20 percent of the useful life of such systems. Improving the state of the art for large scale systems integration has potential to increase the scientific productivity of these systems. Sites have significant expertise, but there are no easy ways to leverage this expertise among them . Many issues inhibit the sharing of information, including available time and effort, as well as issues with sharing proprietary information. Vendors also benefit in the long run from the solutions to issues detected during site testing and integration. There is a great deal of enthusiasm for making large scale system integration a full-fledged partner along with the other major thrusts supported by funding agencies in the definition, design, and use of a petascale systems. Integration technology and issues should have a full 'seat at the table' as petascale and exascale initiatives and programs are planned. The workshop attendees identified a wide range of issues and suggested paths forward. Pursuing these with funding opportunities and innovation offers the opportunity to dramatically improve the state of large scale system integration.
Date: October 1, 2007
Creator: Kramer, William T.C.; Walter, Howard; New, Gary; Engle, Tom; Pennington, Rob; Comes, Brad et al.
Partner: UNT Libraries Government Documents Department

Application of Frequency-Modified Life Approach to the Low-Cycle Fatigue Behavior of Type 304 Stainless Steel

Description: The application of the frequency-modified life equation to fatigue life prediction has been critically examined using the extensive fatigue data generated for Type 304 stainless steel at 1100 degrees F under a variety of cyclic-loading conditions. The parameters that enter into the frequency-modified life equation vary with strain rate and show a transition coinciding with the frequency of cycling at which a change in the fracture appearance from predominantly transgranular to predominantly intergranular failure mode or vice versa occurs. The accuracy in life prediction is improved when the effect of strain rate on life-predictive parameters is considered. It is shown how the effect of compressive and symmetric hold time on fatigue life can be taken into account. A comparison between the frequency-modified life approach of Coffin and the damage-rate approach recently developed by Majumdar and Maiya is also made to show the importance of wave-shape on low-cycle fatigue life.
Date: May 1976
Creator: Maiya, P. S. & Majumdar, S.
Partner: UNT Libraries Government Documents Department

Stress Voiding in IC Interconnects - Rules of Evidence for Failure Analysts

Description: Mention the words ''stress voiding'', and everyone from technology engineer to manager to customer is likely to cringe. This IC failure mechanism elicits fear because it is insidious, capricious, and difficult to identify and arrest. There are reasons to believe that a damascene-copper future might be void-free. Nevertheless, engineers who continue to produce ICs with Al-alloy interconnects, or who assess the reliability of legacy ICs with long service life, need up-to-date insights and techniques to deal with stress voiding problems. Stress voiding need not be fearful. Not always predictable, neither is it inevitable. On the contrary, stress voids are caused by specific, avoidable processing errors. Analytical work, though often painful, can identify these errors when stress voiding occurs, and vigilance in monitoring the improved process can keep it from recurring. In this article, they show that a methodical, forensics approach to failure analysis can solve suspected cases of stress voiding. This approach uses new techniques, and patiently applies familiar ones, to develop evidence meeting strict standards of proof.
Date: September 17, 1999
Creator: FILTER, WILLIAM F.
Partner: UNT Libraries Government Documents Department

Issues Impacting Refractory Service Life in Biomass/Waste Gasification

Description: Different carbon sources are used, or are being considered, as feedstock for gasifiers; including natural gas, coal, petroleum coke, and biomass. Biomass has been used with limited success because of issues such as ash impurity interactions with the refractory liner, which will be discussed in this paper.
Date: March 1, 2007
Creator: Bennett, J.P.; Kwong, K.-S. & Powell, C.A.
Partner: UNT Libraries Government Documents Department

VALIDATION OF SPRING OPERATED PRESSURE RELIEF VALVE TIME TO FAILURE AND THE IMPORTANCE OF STATISTICALLY SUPPORTED MAINTENANCE INTERVALS

Description: The Savannah River Site operates a Relief Valve Repair Shop certified by the National Board of Pressure Vessel Inspectors to NB-23, The National Board Inspection Code. Local maintenance forces perform inspection, testing, and repair of approximately 1200 spring-operated relief valves (SORV) each year as the valves are cycled in from the field. The Site now has over 7000 certified test records in the Computerized Maintenance Management System (CMMS); a summary of that data is presented in this paper. In previous papers, several statistical techniques were used to investigate failure on demand and failure rates including a quantal response method for predicting the failure probability as a function of time in service. The non-conservative failure mode for SORV is commonly termed 'stuck shut'; industry defined as the valve opening at greater than or equal to 1.5 times the cold set pressure. Actual time to failure is typically not known, only that failure occurred some time since the last proof test (censored data). This paper attempts to validate the assumptions underlying the statistical lifetime prediction results using Monte Carlo simulation. It employs an aging model for lift pressure as a function of set pressure, valve manufacturer, and a time-related aging effect. This paper attempts to answer two questions: (1) what is the predicted failure rate over the chosen maintenance/ inspection interval; and do we understand aging sufficient enough to estimate risk when basing proof test intervals on proof test results?
Date: February 18, 2009
Creator: Gross, R & Stephen Harris, S
Partner: UNT Libraries Government Documents Department

DEGRADATION OF FIBERBOARD IN MODEL 9975 PACKAGE FOLLOWING ENVIRONMENTAL CONDITIONING FIRST INTERIM REPORT

Description: Fiberboard material, used in the 9975 shipping package, has been tested for thermal, mechanical and physical properties following environmental conditioning for periods up to 64 weeks. The environments are either representative or bounding of KAMS storage conditions, in order to provide prediction of long-term performance of the 9975 package in KAMS. This report summarizes the data and analysis performed to date. These data show degradation of some properties in some of the environments, but samples have not degraded beyond identified minimum KAMS requirements. Statistical analysis of the data collected to date support the development of a model to predict a service life in KAMS. Further model development and lifetime predictions will be made following additional conditioning and testing in accordance with the task technical plan.
Date: June 13, 2007
Creator: Daugherty, W & Stephen Harris, S
Partner: UNT Libraries Government Documents Department

TESTING OF TMR SAND MANTIS FINAL REPORT

Description: Screening tests of Sand Mantis candidate materials selected for erosion resistance have been completed. The results of this testing identified that over a relatively short period of operation (<1 hour), measurable erosion will occur in each of the candidate zoom tube materials given equal operating exposure. Additionally, this testing has shown that erosion of the rubber discharge hose directly downstream of the vehicle could be expected to limit the service life of the discharge hose. On the basis of these test results, SRNL recommends the following; {lg_bullet} redesign of critical system components (e.g., zoom tube, discharge hose) should be conducted to improve system characteristics relative to erosion and capitalize on the results of this testing, {lg_bullet} continued efforts to deploy the Sand Mantis should include testing to better define and optimize operating parameters, and gain an understanding of system dynamics, {lg_bullet} discontinue wear testing with the selected materials pending redesign of critical system components (1st recommendation) and inclusion of other candidate materials. The final selection of additional candidate materials should be made following design changes, but might include a Stellite alloy or zirconia.
Date: June 12, 2007
Creator: Krementz, D & William Daugherty, W
Partner: UNT Libraries Government Documents Department

Rolling Contact Fatigue of Ceramics

Description: High hardness, low coefficient of thermal expansion and high temperature capability are properties also suited to rolling element materials. Silicon nitride (Si{sub 3}N{sub 4}) has been found to have a good combination of properties suitable for these applications. However, much is still not known about rolling contact fatigue (RCF) behavior, which is fundamental information to assess the lifetime of the material. Additionally, there are several test techniques that are employed internationally whose measured RCF performances are often irreconcilable. Due to the lack of such information, some concern for the reliability of ceramic bearings still remains. This report surveys a variety of topics pertaining to RCF. Surface defects (cracks) in Si{sub 3}N{sub 4} and their propagation during RCF are discussed. Five methods to measure RCF are then briefly overviewed. Spalling, delamination, and rolling contact wear are discussed. Lastly, methods to destructively (e.g., C-sphere flexure strength testing) and non-destructively identify potential RCF-limiting flaws in Si{sub 3}N{sub 4} balls are described.
Date: September 1, 2006
Creator: Wereszczak, Andrew A; Wang, W.; Wang, Y.; Hadfield, M.; Kanematsu, W.; Kirkland, Timothy Philip et al.
Partner: UNT Libraries Government Documents Department

Geothermal chemical control and monitoring instrumentation - an overview

Description: The authors must have accurate knowledge of the geothermal fluid chemistry at operating temperature if they are to optimize operation, prevent corrosion, increase equipment service life and maximize profit and use. Available electrochemical sensors do not survive at the temperatures encountered in geothermal fluids; and new developments in this area are required. In order to fill this gap in technology, the Pacific Northwest Laboratory (PNL) is developing chemical control and monitoring instruments for measuring in situ characteristics of geothermal fluids. Progress in the development of electrochemical sensors to measure pH, carbonate and sulfide-sulfur is discussed.
Date: October 8, 1982
Creator: Jensen, G.A.
Partner: UNT Libraries Government Documents Department

Highly Insulating Windows for Improved Energy Efficiency and Reliability in Fenestration Applications

Description: EverSealed Windows, Inc. (ESW) agreed in early 2006, prior to the contract award, to add three additional deliverables to the Project (new Milestones 30, 31 and 32), and have the results of these three deliverables form the basis of the go/no-go decision for proceeding from BP1 to BP2. ESW completed all three milestones and the DOE agreed in November 2006 to continue the Project. ESW subsequently initiated work on BP2 and its two milestones. These were to (1) Assemble and test glass-to-metal bonded coupons to test the strength of ESW's glass-to-metal bonds (ESW's Test Vehicle 1 or TV1), and (2) to assemble and test the hermeticity of glass and metal packages (ESW's Test Vehicle 2 or TV2). ESW completed both milestones of BP2 in late 2010, demonstrating that its bonds were both strong enough and hermetic enough that vacuum insulating glass units could be assembled and survive a 40+ year service life in any climate in North America. Based on the accomplishments in BP-1, the DOE held a go/no-go meeting in Washington, DC in mid-November 2006 and moved the Project into Budget Period 2 (BP-2). During this go/no-go meeting, the DOE expressed a concern that ESW did not have a back-up plan or process should ESW be unable to make its diffusion bonding process more than adequate for the necessary bond strength and hermeticity of the seal. ESW suggested and volunteered to investigate using a glass frit (i.e., solder glass) as a back-up to its diffusion bonding of glass to oxidized metal.
Date: November 30, 2010
Creator: Stark, David
Partner: UNT Libraries Government Documents Department

Development of an Accurate Feed-Forward Temperature Control Tankless Water Heater

Description: The following document is the final report for DE-FC26-05NT42327: Development of an Accurate Feed-Forward Temperature Control Tankless Water Heater. This work was carried out under a cooperative agreement from the Department of Energy's National Energy Technology Laboratory, with additional funding from Keltech, Inc. The objective of the project was to improve the temperature control performance of an electric tankless water heater (TWH). The reason for doing this is to minimize or eliminate one of the barriers to wider adoption of the TWH. TWH use less energy than typical (storage) water heaters because of the elimination of standby losses, so wider adoption will lead to reduced energy consumption. The project was carried out by Building Solutions, Inc. (BSI), a small business based in Omaha, Nebraska. BSI partnered with Keltech, Inc., a manufacturer of electric tankless water heaters based in Delton, Michigan. Additional work was carried out by the University of Nebraska and Mike Coward. A background study revealed several advantages and disadvantages to TWH. Besides using less energy than storage heaters, TWH provide an endless supply of hot water, have a longer life, use less floor space, can be used at point-of-use, and are suitable as boosters to enable alternative water heating technologies, such as solar or heat-pump water heaters. Their disadvantages are their higher cost, large instantaneous power requirement, and poor temperature control. A test method was developed to quantify performance under a representative range of disturbances to flow rate and inlet temperature. A device capable of conducting this test was designed and built. Some heaters currently on the market were tested, and were found to perform quite poorly. A new controller was designed using model predictive control (MPC). This control method required an accurate dynamic model to be created and required significant tuning to the controller before good control ...
Date: June 30, 2008
Creator: Yuill, David
Partner: UNT Libraries Government Documents Department

LIFETIME PREDICTION FOR MODEL 9975 O-RINGS IN KAMS

Description: The Savannah River Site (SRS) is currently storing plutonium materials in the K-Area Materials Storage (KAMS) facility. The materials are packaged per the DOE 3013 Standard and transported and stored in KAMS in Model 9975 shipping packages, which include double containment vessels sealed with dual O-rings made of Parker Seals compound V0835-75 (based on Viton{reg_sign} GLT). The outer O-ring of each containment vessel is credited for leaktight containment per ANSI N14.5. O-ring service life depends on many factors, including the failure criterion, environmental conditions, overall design, fabrication quality and assembly practices. A preliminary life prediction model has been developed for the V0835-75 O-rings in KAMS. The conservative model is based primarily on long-term compression stress relaxation (CSR) experiments and Arrhenius accelerated-aging methodology. For model development purposes, seal lifetime is defined as a 90% loss of measurable sealing force. Thus far, CSR experiments have only reached this target level of degradation at temperatures {ge} 300 F. At lower temperatures, relaxation values are more tolerable. Using time-temperature superposition principles, the conservative model predicts a service life of approximately 20-25 years at a constant seal temperature of 175 F. This represents a maximum payload package at a constant ambient temperature of 104 F, the highest recorded in KAMS to date. This is considered a highly conservative value as such ambient temperatures are only reached on occasion and for short durations. The presence of fiberboard in the package minimizes the impact of such temperature swings, with many hours to several days required for seal temperatures to respond proportionately. At 85 F ambient, a more realistic but still conservative value, bounding seal temperatures are reduced to {approx}158 F, with an estimated seal lifetime of {approx}35-45 years. The actual service life for O-rings in a maximum wattage package likely lies higher than the estimates due to ...
Date: November 24, 2009
Creator: Hoffman, E. & Skidmore, E.
Partner: UNT Libraries Government Documents Department

DESTRUCTIVE EXAMINATION OF SHIPPING PACKAGE 9975-00600

Description: The Savannah River Site (SRS) stores packages containing plutonium (Pu) materials in the K-Area Complex (KAC). The Pu materials are packaged per the DOE 3013 Standard and stored within Model 9975 shipping packages in KAC. The KAC facility DSA (Document Safety Analysis) [1] credits the Model 9975 package to perform several safety functions, including criticality, impact resistance, containment, and fire resistance to ensure the plutonium materials remain in a safe configuration during normal and accident conditions. The Model 9975 package is expected to perform its safety function for at least 12 years from initial packaging. The DSA recognizes the degradation potential for the materials of package construction over time in the KAC storage environment and requires an assessment of materials performance to validate the assumptions of the analysis and ultimately predict service life. As part of the comprehensive Model 9975 package surveillance program [2-3], destructive examination of package 9975-00600 was performed following field surveillance in accordance with Reference [4]. Field surveillance of the Model 9975 package in KAC included nondestructive examination of the drum, fiberboard, lead shield and containment vessels [5]. Results of the field surveillance are provided in Attachment 1. Destructive and non-destructive examinations have been performed on specified components of shipping package 9975-00600. For those attributes that were also measured during the field surveillance, no significant changes were observed. Three conditions were identified that do not meet inspection criteria. These conditions are subject to additional investigation and disposition by the Surveillance Program Authority. The conditions include: (1) The lead shield was covered with a white corrosion layer; (2) The lead shield height dimension exceeded drawing requirements; and (3) Fiberboard thermal conductivity in the axial direction exceeded the specified range. The Surveillance Program Authority was notified of these conditions. All other observations and test results met identified criteria, or ...
Date: October 29, 2007
Creator: Daugherty, W
Partner: UNT Libraries Government Documents Department

FIFTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

Description: A series of experiments to monitor the aging performance of Viton{sup reg.} GLT O-rings used in the Model 9975 package has been ongoing for six years at the Savannah River National Laboratory. Sixty-seven mock-ups of 9975 Primary Containment Vessels (PCVs) were assembled and heated to temperatures ranging from 200 to 450 F. They were leak-tested initially and have been tested at nominal six month intervals to determine if they meet the criterion of leaktightness defined in ANSI standard N14.5-97. Fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 F. High temperature aging continues for 36 GLT O-ring fixtures at 200--350 F. Room temperature leak test failures have been experienced in 5 of the GLT O-ring fixtures aging at 300 and 350 F, and in all 3 of the GLT O-ring fixtures aging at higher temperatures. No failures have yet been observed in GLT O-ring fixtures aging at 200 F for 30--48 months, which is still bounding to O-ring temperatures during storage in KAMS. High temperature aging continues for 6 GLT-S O-ring fixtures at 200--300 F. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 F. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 or 300 F for 19 months. For O-ring fixtures that have failed the room temperature leak test and been disassembled, the O-rings displayed a compression set ranging from 51--95%. This is significantly greater than seen to date for packages inspected during KAMS field surveillance (23% average). For GLT O-rings, service life based on the room temperature leak rate criterion is comparable to that predicted by compression stress relaxation (CSR) data at higher temperatures (350--400 F). While there are no comparable failure ...
Date: November 1, 2010
Creator: Daugherty, W. & Hoffman, E.
Partner: UNT Libraries Government Documents Department

9975 SHIPPING PACKAGE LIFE EXTENSION SURVEILLANCE PROGRAM RESULTS SUMMARY

Description: Results from the 9975 Surveillance Program at the Savannah River Site (SRS) are summarized for justification to extend the life of the 9975 packages currently stored in the K-Area Materials Storage (KAMS) facility from 10 years to 15 years. This justification is established with the stipulation that surveillance activities will continue throughout this extended time to ensure the continued integrity of the 9975 materials of construction and to further understand the currently identified degradation mechanisms. The current 10 year storage life was developed prior to storage. A subsequent report was later used to extend the qualification of the 9975 shipping packages for 2 years for shipping plus 10 years for storage. However the qualification for the storage period was provided by the monitoring requirements of the Storage and Surveillance Program. This report summarizes efforts to determine a new safe storage limit for the 9975 shipping package based on the surveillance data collected since 2005 when the surveillance program began. KAMS is a zero-release facility that depends upon containment by the 9975 to meet design basis storage requirements. Therefore, to confirm the continued integrity of the 9975 packages while stored in KAMS, a 9975 Storage and Surveillance Program was implemented alongside the DOE required Integrated Surveillance Program (ISP) for 3013 plutonium-bearing containers. The 9975 Storage and Surveillance Program performs field surveillance as well as accelerated aging tests to ensure any degradation due to aging, to the extent that could affect packaging performance, is detected in advance of such degradation occurring in the field. The Program has demonstrated that the 9975 package has a robust design that can perform under a variety of conditions. As such the primary emphasis of the on-going 9975 Surveillance Program is an aging study of the 9975 Viton(reg.sign) GLT containment vessel O-rings and the Celotex(reg.sign) fiberboard thermal ...
Date: January 6, 2011
Creator: Daugherty, W.; Dunn, K.; Hackney, B.; Hoffman, E. & Skidmore, E.
Partner: UNT Libraries Government Documents Department

Surface selective membranes for carbon dioxide separation

Description: In this study, hybrid membranes have been developed for the selective separation of CO2 from mixtures containing H2. Beginning with commercially available Pall alumina membrane tubes with nominal pore diameter of 5 nm, hybrids were produced by silation with a variety of functionalities designed to facilitate the selective adsorption of CO2 onto the pore surface. The goal is to produce a membrane which can harness the power of surface diffusion to give the selectivity of polymer membranes with the permeance of inorganic membranes.
Date: September 1, 2005
Creator: Luebke, D.R.; Pennline, H.W. & Myers, C.R.
Partner: UNT Libraries Government Documents Department

PCC2005 Sample

Description: Considered herein is a process concept that integrates fly ash amendment of brine produced as a result of oil and gas extraction with subsequent sequestration of carbon dioxide in the resulting alkaline solution. The CO2 solubility-trapping capacity of the alkaline mixture is substantially greater than that of the acidic raw brine. In addition to pH adjustment, addition of CaO-rich combustion byproduct augments the concentration of Ca++ cations initially present in the brine to increase solution capacity for mineral trapping of CO2. One- and two-stage approaches for implementation of this treatment process were considered. Batch reactions were conducted with several Class C fly ashes and one flue gas desulfurization (FGD) byproduct. Preliminary results verify the potential to substantially enhance CO2 sequestration capacity and increase mineral sequestration of absorbed CO2, primarily as CaCO3. Feasibility of the described CO2 sequestration treatment concept was, therefore, successfully demonstrated.
Date: September 1, 2005
Partner: UNT Libraries Government Documents Department

Gasification CFD Modeling for Advanced Power Plant Simulations

Description: In this paper we have described recent progress on developing CFD models for two commercial-scale gasifiers, including a two-stage, coal slurry-fed, oxygen-blown, pressurized, entrained-flow gasifier and a scaled-up design of the PSDF transport gasifier. Also highlighted was NETL’s Advanced Process Engineering Co-Simulator for coupling high-fidelity equipment models with process simulation for the design, analysis, and optimization of advanced power plants. Using APECS, we have coupled the entrained-flow gasifier CFD model into a coal-fired, gasification-based FutureGen power and hydrogen production plant. The results for the FutureGen co-simulation illustrate how the APECS technology can help engineers better understand and optimize gasifier fluid dynamics and related phenomena that impact overall power plant performance.
Date: September 1, 2005
Creator: Zitney, S.E. & Guenther, C.P.
Partner: UNT Libraries Government Documents Department