Performance of Elastomers in Isolation Bearings: A Literature Review

1992 ◽  
Vol 8 (2) ◽  
pp. 279-303 ◽  
Author(s):  
Andrew W. Taylor ◽  
Albert N. Lin ◽  
Jonathan W. Martin
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
The United States ◽  
High Energy ◽  
Laboratory Findings ◽  
Elastomeric Bearings ◽  
Performance Requirements ◽  
Long Term Performance ◽  
Term Performance

Laminated elastomeric bearings have been used for about 30 years in the United States to isolate bridge substructures from the lateral forces induced by shrinkage and creep of their superstructures. More recently, elastomeric bearings have been increasingly employed in buildings and bridges as a means of decoupling the structure from seismic ground motions. Since most buildings and bridges have service lives of at least 30 to 60 years, questions about the long-term behavior of base-isolation bearings arise. This paper presents a review of literature relating to the long term performance of the elastomers used in seismic isolation bearings. Bearing performance requirements are discussed and material characteristics and fabrication procedures are outlined. Field experience and laboratory findings are reviewed. Finally, long-term environmental effects are discussed, including ozone degradation, corrosion, temperature effects, and the influence of bombardment of elastomers by high energy radiation.

A High Temperature and UV Stable Vapor Phase Polymer for Electronics Applications

2011 ◽  
Vol 2011 (HITEN) ◽  
pp. 000207-000214
Author(s):  
Rakesh Kumar
Keyword(s):  
High Temperature ◽  
Electronic Devices ◽  
Electronics Industry ◽  
Performance Requirements ◽  
Cell Components ◽  
Temperature Exposure ◽  
Electronic Parts ◽  
Long Term Performance ◽  
Term Performance

A recent development in the area of high temperature and UV stable polymers, which offers solutions to many existing packaging and reliability challenges of electronics industry, is described. Packaging, protection and reliability of various electronic devices and component, including PCB's, MEMS, optoelectronic devices, fuel cell components and nano-electronic parts are, becoming more challenging due to their long-term performance requirements. This high temperature polymer, named Parylene HT, offers solutions to many existing protective, packaging and reliability issues in the electronics and medical industries, in part because of its excellent electrical and mechanical properties, chemical inertness and long-term thermal stability at high temperature exposure (up to 350°C long-term and short-term at 450 °C). Experimental results and trial runs demonstrate the ability of Parylene HT coating to meet the growing requirements of higher dielectric capabilities, higher temperature integrity, mechanical processing, etc. of a dynamic electronics industry. In addition, Parylene HT polymer coating truly conforms to parts due to its molecular level deposition characteristics. Its suitability and biocompatibility encourage researchers to explore Parylene HT's role in sensors and in active electronic devices for various industries.

Advanced Techniques for Establishing Long-Term Performance of Composite Repair Systems

2014 ◽  
Author(s):  
Chris Alexander
Keyword(s):  
The United States ◽  
Operating Conditions ◽  
Repair System ◽  
Composite Repair ◽  
Design Life ◽  
Repair Systems ◽  
Long Term Performance ◽  
Term Performance ◽  
Composite Repairs

Although composite materials are used to repair and reinforce a variety of anomalies in high pressure transmission gas and liquid pipelines, there continues to be widespread debate regarding what constitutes a long-term composite repair. The United States regulations require that composite repairs must be able to permanently restore the serviceability of the repaired pipeline, while in contrast the Canadian regulations take a more prescriptive approach by integrating the ASME PCC-2 and ISO 24817 composite repair standards along with a requirement for establishing a 50-year design life. In this paper the author provides a framework for what should be considered in qualifying a composite repair system for long-term performance by focusing on the critical technical aspects associated with a sound composite repair. The presentation includes a discussion on establishing an appropriate composite design stress using the existing standards, using full-scale testing to ensure that stresses in the repair do not exceed the designated composite design stresses, and guidance for operators in how to properly integrate their pipeline operating conditions to establish a design life. By implementing the recommendations presented in this paper, operators will be equipped with a resource for objectively evaluating the composite repair systems used to repair their pipeline systems.

Updated Review of Stone Matrix Asphalt and Superpave® Projects

2003 ◽  
Vol 1832 (1) ◽  
pp. 217-223 ◽  
Author(s):  
Donald E. Watson
Keyword(s):  
Material Properties ◽  
The United States ◽  
Mix Design ◽  
Stone Matrix Asphalt ◽  
High Traffic Volume ◽  
Long Term Performance ◽  
Term Performance ◽  
Stone Matrix

Stone matrix asphalt (SMA) and Superpave® represent relatively new mix design technologies in the United States. Therefore, a condition survey was conducted of mixes that had been in service for several years to evaluate the long-term performance of SMA and Superpave projects. This study is a follow-up to a 1995 review of SMA projects and a 1998 review of Superpave projects. Both SMA and Superpave are acknowledged to be rut-resistant mixes, and this resistance was shown to be the case during this project review. However, a significant amount of cracking occurred early in the life of some of these mixtures. Overall, the SMA mixtures appeared to be more durable than the Superpave mixtures evaluated. The SMA mixtures have been in place about 2½ years longer than the Superpave mixtures, but the overall condition is about the same. Some of the primary conclusions from the survey are as follows: both SMA and Superpave mixtures were shown to be rut-resistant even when placed on facilities with high traffic volume; much of the observed cracking, especially load cracking, appeared to be more related to problems other than mix design or material properties; and SMA mixtures can be expected to last longer than Superpave mixtures before reaching the same condition level.

Radiocarbon Analysis on the New AARAMS 1MV Tandetron

Radiocarbon ◽  
2016 ◽  
Vol 59 (3) ◽  
pp. 905-913 ◽  
Author(s):  
Jesper Olsen ◽  
Dmitry Tikhomirov ◽  
Claus Grosen ◽  
Jan Heinemeier ◽  
Matthias Klein
Keyword(s):  
Standard Deviation ◽  
Charge State ◽  
High Energy ◽  
International Standards ◽  
Electrostatic Analyzer ◽  
Consensus Values ◽  
Long Term Performance ◽  
Term Performance

AbstractWe report here on the radiocarbon performance on the AARAMS HVE 1MV Tandetron. 14C analysis is carried out in charge state 2+. We have avoided Li interference by appropriate settings of the high-energy electrostatic analyzer and the 30° second high-energy magnet. The 14C machine background is determined using unprocessed graphite, which yielded 58,650±2032 14C yr determined as the average and standard deviation of four measurements. International standards, which are used to monitor the long-term performance of the 14C measurements, agree with the reported consensus values.

Doe Progress in Assessing the Long Term Performance of Waste Package Materials

1986 ◽  
Vol 84 ◽  
Author(s):  
A. Berusch ◽  
E. Gause
Keyword(s):  
Site Characterization ◽  
The United States ◽  
High Level Waste ◽  
Design Studies ◽  
Waste Package ◽  
License Application ◽  
High Level ◽  
Long Term Performance ◽  
Term Performance

Summary:Each of the projects has made significant progress toward the eventual operation of a repository for the disposal of high-level radioactive wastes in the United States. Although much has been accomplished, much remains to be done. For example, the Site Characterization Plans for BWIP and NNWSI are nearing completion to be followed by initiation of site characterization activities. The Site Characterization Plan for the selected salt site is scheduled for completion later in 1987. Waste package advanced conceptual design studies are currently scheduled to begin at each project before the end of FY 1987. These efforts will lead to selections of concepts to be detailed in the license application design phase. Compliance with the NRC criteria that require long-term waste package performance will be demonstrated by DOE by performing all of the aforementioned activities. In doing so, the DOE will also be assured that its plan for the safe disposal of high-level waste will be satisfactorily implemented.

Asphalt Trackbed Technology Development: The First 20 Years

2000 ◽  
Vol 1713 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Jerry G. Rose ◽  
E. Ray Brown ◽  
Monica L. Osborne
Keyword(s):  
Technology Development ◽  
The United States ◽  
Optimum Moisture Content ◽  
Performance Evaluations ◽  
Track Structure ◽  
Maintenance Costs ◽  
Rail Network ◽  
Long Term Performance ◽  
Term Performance

The evolution of hot-mix asphalt (HMA) trackbed technology is documented as presently practiced in the United States. Criteria used in selecting sites for and the attendant benefits of HMA trackbeds, based on long-term performance evaluations, are discussed. Prevailing practices for selecting ideal HMA mix parameters, trackbed section designs, and application procedures are described in detail. Primary attention is directed at the “underlayment” procedure in which the HMA serves as a premium subballast layer within the track structure to enhance the support, waterproofing, and confinement properties of the subballast. The roadbed or subgrade materials underlying the HMA mats maintain near-optimum moisture content. The HMA appears to undergo little if any weathering or deterioration in the trackbed environment. The resultant benefits are decreased maintenance costs, fewer slow orders, fewer operational interferences, and improved operational efficiency of the rail network overall.

Lessons Learned from the Yucca Mountain and WIPP Projects

2010 ◽  
Vol 73 ◽  
pp. 194-202 ◽  
Author(s):  
Evaristo J. Bonano ◽  
David S. Kessel ◽  
Lori J. Dotson
Keyword(s):  
System Analysis ◽  
The United States ◽  
Yucca Mountain ◽  
Lessons Learned ◽  
Total System ◽  
Waste Isolation Pilot Plant ◽  
License Application ◽  
Long Term Performance ◽  
Term Performance

For more than 30 years Sandia National Laboratories (SNL) has played a key role in the development and implementation of total system analyses of waste management systems in the United States. Two very important applications have been the total system analysis of long term performance that supported (1) the Compliance Certification Application (CCA) for the Waste Isolation Pilot Plant (WIPP) in 1996 and (2) the License Application (LA) for the Yucca Mountain (YM) Repository in 2008.

Selected In-Track Applications and Performances of Hot-Mix Asphalt Trackbeds

2013 ◽  
Author(s):  
Jerry G. Rose
Keyword(s):  
Impact Load ◽  
The United States ◽  
Factors Affecting ◽  
Support Materials ◽  
Maintenance And Rehabilitation ◽  
A Site ◽  
Engineering Practices ◽  
Long Term Performance ◽  
Term Performance

The use of a layer of asphalt within railway trackbeds has steadily grown since the early 1980s in the United States. Its primary use has been for maintenance and rehabilitation applications in existing tracks, particularly at special trackworks, to improve trackbed performance, and to a lesser extent for new trackbed applications where the projected long-term performance of the asphalt trackbed is anticipated to be economically justified. Normally the asphalt layer is 6 in. (150 mm) thick, placed on a prepared subgrade or granular subballast, and is subsequently topped with a layer of typical ballast. Accepted highway/railway construction practices are adhered to, including adequate preparation and compaction of the support layers. In addition, surface and sub-surface drainage aspects are evaluated on a site-specific basis and improvements are specified based on accepted engineering practices. This application does not deviate significantly from conventional all-granular trackbed designs, except the asphalt layer is substituted for a portion of the thickness of the granular subballast and ballast support materials. Described herein are 1) typical trackbed designs, 2) in-track applications, and 3) long-term performance evaluations for various types of major applications on several U.S. Class I railroads, namely NS, UP, CSX, and BNSF, and a limited number of Shortline railroads. Specifically addressed are rehabilitation applications for special trackworks — tunnel floors/approaches, wheel impact load detectors, bridge approaches, rail-highway crossings, turnouts, rail crossings, and rail crossovers — plus descriptions for a limited number of new double-tracking open-track installations. Brief descriptions are provided for international applications in six countries. Particular detail is given to factors affecting the economic justification for utilizing this technology based on long-term performances and historical evaluations of numerous installations. Details are provided relative to unique conditions and logistics related to the application of the layer of asphalt within the trackbed support for the special trackworks and selected open-track installations. Several specific installations are highlighted.

Parylene HT®: A High Temperature Vapor Phase Polymer for Electronics Applications

2010 ◽  
Vol 2010 (HITEC) ◽  
pp. 000108-000113
Author(s):  
Rakesh Kumar
Keyword(s):  
High Temperature ◽  
Electronic Devices ◽  
Electronics Industry ◽  
Performance Requirements ◽  
Cell Components ◽  
Temperature Exposure ◽  
Electronic Parts ◽  
Long Term Performance ◽  
Term Performance

A development in the area of high temperature polymers, which offers solutions to many existing packaging and reliability challenges of electronics industry, is described. Packaging, protection and reliability of various electronic devices and components that include PCB's, MEM's, optoelectronic devices, fuel cell components and nano-electronic parts are becoming more challenging due to their long-term performance requirements. Parylene HT offers solutions to many existing packaging and reliability issues of electronics industry in part because of its excellent electrical & mechanical properties, chemical inertness and long-term thermal stability at high temperature exposure to over 350°C (short-term at 450 °C). Experimental results and trial runs demonstrate the ability of Parylene HT coating to meet the growing requirements of higher dielectric capabilities, higher temperature integrity and mechanical processing etc. of dynamic electronic industry. In addition, Parylene HT polymer coating truly conforms to the parts due to its molecular level deposition characteristics. Its suitability and biocompatibilty encourage researchers to explore Parylene HT's role in sensors and in active electronic devices for various industries, which include enhancing high temperature application/technologies.

Sign in / Sign up

Export Citation Format

Share Document