bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural Implications of Poor Bridge Surface Performance
Authors: Yanev BS
Published: March 2009

There are approximately 2,100 bridges in the Metropolitan area of New York City; 842 of the bridges, counting over 4,500 spans, are the responsibility of the City administration. According to New York State inspection records, 56% of these bridges are rated less than 4.5 on a 7 grade system. This is regarded by the New York City Department of Transportation (NYC DOT) Bridge Bureau as an indication of the need for structural repair of some magnitude. In the situation involving 42% of the City's bridges, a ten-year, $3.5 billion program envisions complete rehabilitation. A recent NYC DOT study examined the remaining 58% of the bridges and concluded that considerable structural repairs are necessary in order to avoid the need for premature rebuilding of that portion as well.

A further step is the identification of structural components requiring repair or replacement, and the optimal frequency of such measures. A program for component rehabilitation is expected as a result of this study. The elimination of certain problem-prone structural components from future design can be considered as well. Ultimately, schedules for timely repairs can be generated in order to extend the useful life of a bridge. This is viewed as a supplement to the New York City Preventive Maintenance Program which is already applied to bridges in good condition. The following structural components emerge as the primary sources of problems on most of the bridges:

Joints—Approximately 90% of the structural deterioration is concentrated in the vicinity of joints and is precipitated by joint failure. Experience suggests that “the only good joint is no joint.” Yet joints are inevitable and their maintenance while still in serviceable condition is vital to the structure as well as to traffic.

Drainage—More than 60% of the bridge drainage systems are rated “not functioning as designed.” This results in saturating bridge decks and the entire superstructures with water and de-icing salt, causing rapid corrosion.

Wearing Surface—Deck—The deck and wearing surface, frequently monolithic in recent years, are the first to suffer from the malfunctioning of the above components. Further, they are subjected to the increasingly severe dynamic loadings due to the growing volume and weight of traffic.

The consequences to the bridge structure are grave. Concrete piers crack, spall and fail due to the dynamic loadings. Steel members crack under the combined effect of fatigue and corrosion. In all of these cases, problems originate at the roadway surface and rapidly propagate throughout the structure. The progress of this path of rapid deterioration is traced for several bridge types frequently encountered in New York. Measures used with limited success in mitigating the surface and structural deficiencies are described.
Impact of the 1990 Clean Air Act Amendments on Motor Fuel-An Overview
Authors: Wilson RD
Published: March 2009

The 1990 Clean Air Act Amendments contain a number of provisions related to the fuels used in motor vehicles. These regulatory programs will affect fuel quality in a number of ways. The regulations cover the following aspects of fuels: gasoline volatility, diesel fuel quality, oxygenated fuels, reformulated gasoline and clean alternative fuels. Each of these regulations and their impact on fuel quality is discussed.
The Impact of State Air Quality and Product Regulations on Current and Future Fuel Properties
Authors: Gibbs LM
Published: March 2009

In order to meet federal ambient air quality standards, a number of states and localities have issued fuel regulations to help control the emissions from motor vehicles and from the fuel distribution system. The state of California has led the nation in developing air quality standards. Some states are considering adopting California regulations. Most states have product inspection laws and minimum quality standards for fuels. This paper discusses the air quality and product regulations and how they can impact current and future properties of fuels for motor vehicles. Also discussed is the relationship between the state regulations and the implementation of the 1990 Clean Air Act Amendments.
The Effect of Reformulated Gasoline on Other Products
Authors: Jones RL , Williams JE
Published: March 2009

The paper discusses the possible impact of various gasoline reformulations on the manufacture of other products including jet fuel, diesel fuel and heating oil. The paper also addresses concurrent effects of regulatory requirements covering diesel fuel. Changes in military and commercial jet fuels are reviewed. Refinery process changes are assessed for product quality impact. The paper also suggests areas where refinery process changes may indicate a need for reassessments of product standards and where such changes as well as government regulations indicate a need for new or improved test methods.
The Impact of the Clean Air Act on Multi-Product Pipelines
Authors: Mason RC
Published: March 2009

Large multi-product pipelines currently face major problems in fuel storage capacity and product interface disposal as petroleum volumes are expected to increase. Additional fuel grades such as low sulfur diesel fuel and the requirement for highly oxygenated and reformulated gasolines will compound these problems. The paper reviews possible approaches in terms of minimum product tenders, additional quality control measures, additive controls, tankage limitations and interface disposal. Anticipated difficulties are also discussed as is the need for rapid field tests.
A Comparison of NonCFC and CFC Methods for Removal of Organic and Particulate Contaminant on Stainless Steel Components
Authors: Pedley MD , Janoff D , Johnson H
Published: March 2009

The NASA WSTF evaluated four methods of cleaning that do not involve the use of CFCs and compared the results to current procedures which use CFCs. The cleaning methods investigated were cleaning with an emulsifying agent, steam cleaning, ultrasonic cleaning with an inorganic cleaning agent, and ultrasonic cleaning with an emulsifying agent. Stainless steel components were used in the evaluation. The components were made of 304 stainless steel and were configured as tube elbows, end caps, and straight tubes with female end-fittings. Pieces of each configuration were contaminated with a mixture of particulate, and various greases and oils. The pieces were then cleaned using the WSTF methods, and alternate methods, and the levels of contamination removal, and levels of cleanliness were compared. Results of the evaluation showed that the all of the alternatives were more effective in removing organic contaminants than vapor degreasing with trichloroethane, and some were comparable to the WSTF 3-step process involving CFCs. The most effective alternative was ultrasonic cleaning with an emulsifying agent. The investigation also showed that the verification step of rinsing with Freon 113 is not very effective for determining NVR, and is not an adequate method for determining particulate. In several tests, hardware verified as meeting particulate requirements by a Freon 113 rinse released tens of thousands of additional particles when subjected to ultrasound. Freon 113 was far more effective when combined with ultrasound in the removal of organics and particles.
Aqueous Cleaning of Industrial and High-Purity Valves and Fittings: Process Development, Control, and Validation
Authors: Koch UH , Kmetko CJ
Published: March 2009

Aqueous cleaning processes were developed to replace chlorinated fluorocarbon solvents for cleaning industrial valves and fittings. Additional processes were developed for the ultra-clean requirements of special applications such as oxygen systems, high-purity electronic gases, and biotechnology processes. Development of cleaning processes and methods is described. Test methods developed to qualify and control the processes and verify the resultant products are described. Data on hydrocarbon residues, particle contamination, ionic residues, and adsorbed moisture are presented. Comparative data for solvent cleaning methods are presented to show that the aqueous cleaning processes are superior to traditional methods.
Methods for Using Water Impingement in Lieu of Chlorofluorocarbon 113 for Determining the Non-Volatile Residue Level on Precision Cleaned Hardware
Authors: Dearing WL , Bales LD , Bassett CW , Caimi RE , Lafferty GM , Melton GS , Sorrell DL , Thaxton EA
Published: March 2009

Chlorofluorocarbon (CFC) 113 is currently in use at the John F. Kennedy Space Center as a cleaning verification solvent. A CFC 113 rinse is routinely used to verify that valves and other large components meet a non-volatile residue (NVR) requirement of less than 1 mg per 0.09 m2 (1 ft2) of surface area. The National Aeronautics and Space Administration plans to eliminate the use of CFC 113 for NVR analysis by 1995. Data is presented from a test program in progress to develop water impingement NVR processes. Contaminant removal tests were conducted on stainless steel test plates using three water impingement methods, liquid, steam, and gas/liquid. The use of total organic carbon analysis to determine the NVR cleanliness level is also discussed.
A Demonstrated Detergent Cleaning Technique for Fluorinated Propellant Systems
Authors: Werling RE , Knutson JC
Published: March 2009

This paper discusses the details of a detergent cleaning technique developed by Aerojet Propulsion Division that eliminates the use of CFC fluids in the cleaning of rocket engine test systems and components. The technique was successfully demonstrated during the construction and operation of a rocket engine test facility that uses chlorine pentafluoride (ClF5) and hydrazine (N2H4) propellants during the testing of engine components at thrust levels up to 4 448 N (1 000 lbf). A description of the detergent cleaning apparatus and the procedures used to clean the test stand components to a particulate level 100 (no particles greater than 100 microns), a non volatile residue value less than 43.1 milligrams per square meter (4.0 mg/ft 2) of significant surface area and a hydrocarbon content less than 10.8 milligrams per square meter (1.0 mg/ft 2) of significant surface area is provided. Aerojet's sampling and analysis procedures are also presented. The rocket engine test facility cleaned using the technique is fabricated from commercially available components that are primarily stainless steel and have flow paths less than 1.27 cm (0.5 in) in diameter. Cleaning of the valves, filters, check valves, turbine flowmeters, pressure transducers, and tubing is detailed. The facility has been used to successfully conduct over 5 500 thruster static hot firings, propellant tank sub-system tests and a full system hot fire demonstration consisting of three (3) engines, three (3) propellant tanks and associated propellant delivery and pressurization systems.
Cleaning Aluminum Heat Pipe Casings with Replacements for Ozone-Depleting Chemicals
Authors: Meyers B
Published: March 2009

The internal cleanliness of heat pipe casings used in spacecraft thermal control systems must meet strict non-volatile residue (NVR) and particulate requirements. Presently, Trichloroethane (TCA) is used in the precleaning of heat pipes and 1,1,2 trichloro 1,2,2 Trifluoroethane (CFC-113) is used for precision cleaning. TCA removes oils and other organic contaminants while CFC-113 removes particles and fibers.

A new process was developed and tested for heat pipe casing cleaning using replacements for TCA and CFC-113 which meets NVR and particulate cleanliness requirements. An alkaline cleaner was used instead of TCA for precleaning and deionized water (DI) with a nitrogen gas aeration was used instead of CFC-113 for precision cleaning.

The new process was tested on five heat pipe casings and four of these met the cleanliness requirements of MIL-STD-1246B, level 250D. The five casings were subjected to life tests. After five months, all of the casings have acceptable levels of non-condensable gas (NCG). Solvent extraction (NVR), particulate counts and suface analysis alone do not provide adequate confidence that the heat pipes will perform as intended. A heat pipe's performance is degraded when NCG forms within the pipe. This phenomenon can only be assessed by life testing which involves charging the heat pipe with ammonia and periodically determining the NCG level.
Evaluation of Plasma Cleaning, an Environmentally Friendly Process, for Removing Lubricants from Metallic Surfaces
Authors: Paciej R , Jansen F , Krommenhoek S
Published: March 2009

The effectiveness of plasma cleaning as a substitute for CFCs was compared to two alternative methods, CO2 snow and detergent cleaning. The proposed ASTM G XYZ standard test coupon described in “Standard Practice for Preparation of Contaminated Test Coupons for the Evaluation of Cleaning Agents for Use in Oxygen-Enriched Systems and Components” was used to compare all three cleaning methods. The cleaning experiments employed two different hydrocarbon oils, Precision-D and 3-in-1, which were applied to the test coupons by either dipping the coupons into a lubricant and solvent mixture or spraying the mixture onto the coupons. Also, three different test coupons were chosen for the experiments: AL3003 (aluminum), C1018 (carbon-steel), and CDA706 (brass alloy).

Plasma, CO2 snow, and detergent cleaning were demonstrated to be effective in removing oil contamination from metallic surfaces. CO2 snow and detergent cleaning methods are most beneficial in removing gross oil contamination from rough surfaces. Plasma cleaning which can also be used to remove gross oil contamination is recommended over the other methods when oil contamination must be reduced to very low levels.
A Selection and Evaluation Protocol for Alternatives to Halogenated Hydrocarbon Solvents for Oxygen Cleaning Applications
Authors: Million JF , McIlroy K , Zawierucha R
Published: March 2009

Components and systems for gaseous or liquid oxygen service must be cleaned to eliminate the presence of reactive contaminants. Halogenated solvents such as 1,1,1 trichloroethane have been commonly used as preferred cleaning agents for oxygen systems; however, due to environmental and safety concerns, suitable alternatives are needed.

A substantial amount of work has been done on alternatives by various groups. However, many of these alternatives have limitations which should be identified via standardized comparative tests to identify potential problem areas. Furthermore, guidance on the use of standard tests is required.

It is believed that there is a need to establish a standard protocol for comparative testing of environmentally acceptable Chlorofluorocarbon (CFC) alternatives. A Task Force within the ASTM G-4 Committee has been addressing this matter since January, 1992.

This paper discusses issues critical to such a protocol. In addition, it presents an interim protocol suitable for dialogue between the developers of alternatives to CFC cleaning agents and users of equipment in oxygen enriched atmospheres.
Development of a Wear Test for Adiabatic Diesel Ring and Liner Materials
Authors: Glaeser WA , Gaydos PA
Published: March 2009

A high temperature apparatus has been developed for determining the wear characteristics of refractory materials for piston ring and cylinders in low heat loss advanced diesel engines. Operation of the apparatus has demonstrated good simulation with actual engine experience. Ceramic materials and coatings evaluated include zirconias, silicon carbide, silicon nitride, and two chromium oxides. Both liquid and solid lubricants have also been evaluated with ceramic materials in the apparatus.
Friction Characteristics of Plastic Plain Bearings at Low Velocity
Authors: Budinski KG
Published: March 2009

A study was conducted to compare the friction characteristics of ball bushings and plastic plain bearings for a low-speed mechanical drive. The goal was freedom from stick-slip behavior.

Laboratory tests were conducted to measure the static and kinetic coefficient of friction of 12 bushing/shaft couples. The test results indicated that the most consistent friction characteristics were obtained with bushings made from oil-impregnated ultrahigh molecular weight polyethylene sliding on a hardened steel shaft with a surface roughness of 0.2μm Ra. The variability of the friction force is proposed as the parameter to be measured when freedom from stick-slip behavior is the system goal.
Comparison of Laboratory Abrasion Tests and Field Tests of Materials Used in Tillage Equipment
Authors: Swanson PA
Published: March 2009

In agricultural equipment used for tillage, abrasion by hard particles is a major mode of wear. Field tests and customer surveys of equipment usage can provide valuable data on the rate of wear of different soil working tools. However, it is usually very time consuming and costly to gather this type of information. While field testing will continue to play an important role in the evaluation of agricultural equipment durability, the use of laboratory tests that adequately simulate the wear modes occurring in the field can significantly reduce the amount of field testing required to evaluate wear of tillage tools. In this review, important criteria for determining the degree to which laboratory tests simulate the wear occurring in field tests or service will be presented. These include not only a comparison of the wear rate and relative wear resistance determined from laboratory and field tests, but also a comparison of the worn surfaces to identify the wear mechanisms that are active.

Widely used abrasion tests, including the ASTM G65 Standard Test Method for Measuring Abrasion Using the Dry Sand/Rubber Wheel Apparatus and the G105 Standard Test Method for Conducting Wet Sand/Rubber Wheel Abrasion Tests will be reviewed, and their ability to simulate the wear that occurs in tillage operations will be examined. Examples will be provided that highlight the strengths and weaknesses of these laboratory tests in ranking the abrasion resistance of materials used in soil working tools. A major limitation of all of these tests is their inability to simulate wear that occurs under the combined action of soil abrasion and repeated impacts by rocks. Difficulties associated with the gathering of quantitative field data needed to carry out the comparison of laboratory and field test results will also be discussed.
A Retrospective Survey of the Use of Laboratory Tests to Simulate Internal Combustion Engine Materials Tribology Problems
Authors: Blau PJ
Published: March 2009

Progress in the field of tribology strongly parallels, and has always been strongly driven by, developments and needs in transportation and related industries. Testing of candidate materials for internal combustion engine applications has historically taken several routes: (1) replacement of parts in actual engines subjected to daily use, (2) testing in special, instrumented test engines; (3) and simulative testing in laboratory tribometers using relatively simple specimens. The advantages and disadvantages of each approach are reviewed using historical examples. A four-decade, retrospective survey of the tribomaterials literature focused on the effectiveness of laboratory simulations for engine materials screening. Guidelines for designing and ducting successful tribology laboratory simulations will be discussed. These concepts were used to design a valve wear simulator at Oak Ridge National Laboratory.
Laboratory Wear Tests for Qualifying Automotive Air-Conditioning Lubricants for Use with Refrigerant HFC-134a
Authors: Tseregounis SI , Spearot JA , Rounds FG , Baker JA , Serrianne BC
Published: March 2009

Three laboratory, block-on-ring wear tests were developed to evaluate potential lubricants for automotive air-conditioning (AC) compressors designed to use the alternative refrigerant HFC-134a. The tests were conducted in a pressurized refrigerant atmosphere using stepwise increasing loads. The three tests utilized steel rings and steel, brass, and aluminum blocks, respectively. Using multiple-variable, regression analyses, results from the three laboratory wear tests were used to explain wear phenomena occurring in a variable displacement AC compressor.

Correlations of the laboratory wear test data with data from compressor tests indicated that an optimized compressor lubricant should minimize aluminum and brass wear and maximize steel seizure loads. A variety of additives were evaluated using the three wear tests. Many additives were identified which could increase the seizure load and reduce steel wear. Several additives were capable of reducing brass wear relative to the base fluid in which they were blended. No additives were found to reduce the galling and wear of aluminum. Residual Clcontaining impurities in the HFC-134a refrigerant can increase the load at which seizure occurs in steel-on-steel wear tests.
Friction and Wear Set-Up for Simulation of Knee Joint
Authors: Bahadur S
Published: March 2009

The tribological problems in a knee joint have been discussed. The items examined include the incongruent joint structure, cartilage tissue and its lubrication, kinematics and loading. The reasons why the reciprocating pin-on-flat set-up included in the ASTM F732-82 (Reapproved 1991) standard is not satisfactory for the ranking of candidate materials for joint replacement prostheses are discussed. A set-up incorporating both the sliding and rolling motions is suggested as a better system.
The Use of Surface Layer Activation to Measure Ring Wear in an Operating Heavy Duty Diesel Engine
Authors: Truhan JJ , Covington CB
Published: March 2009

Surface layer activation (SLA) was used to directly measure piston ring wear in an operating heavy duty diesel engine. A top piston ring was irradiated to measure, in situ, wear rates as a function of lube oil cleanliness using naturally aged oil. The relationship between ring wear rate and contamination level in the oil was obtained for different particle size ranges. By the use of a wear model, ring wear rates were used to estimate ring life. The predicted wear calculated by SLA correlated very well to the actual wear as determined by profile traces.
Prediction of the Thermal Performance of Single and Multi-Airspace Reflective Insulation Materials
Authors: Desjarlais AO , Yarbrough DW
Published: March 2009

A recent test program to determine the thermal performance of reflective thermal insulation materials and systems was carried out on behalf of the Department of Energy. This program indicated that the thermal performance of multi-airspace reflective cavities (multi-layer reflective insulations) could not be accurately predicted by a one-dimensional analysis applied in combination with the thermal performance data for single airspaces.

A new correlation has been developed in an effort to improve the accuracy of predicted R-values for multi-airspace reflective systems. This correlation is described and compared to the thermal test data generated by the recent test program.

Generally good agreement between calculated and measured R-Values is achieved for single airspaces. However, calculated values for multiple airspaces are up to 60 percent greater than the measured values. This disagreement indicates that the commercial multifoil product that was tested may not achieve the idealized one-dimensional heat flow that is true of the correlation.
A Survey of Loose-Fill Insulations Installed in Residential Attics
Authors: Penney RA , Yarbrough DW
Published: March 2009

A project to survey the quality of installed loose-fill insulation in Georgia residences resulted in several hundred attic inspections to measure insulation thickness and density. Thermal resistance (R-values) for various types of attic insulation have been calculated using generalized correlations for apparent thermal conductivity as a function of density. The calculated R-values were compared with contracted R-values in an effort to assess the adequacy of current quality control measures. An analysis is presented of the measurements and calculations along with general observations about the installation in the attics that have been inspected.
Zip 2.0: The Enhanced Zip-Code Insulation Program
Authors: Petersen SR
Published: March 2009

ZIP 2.0, the enhanced Zip Code Insulation Program, determines economic levels of thermal insulation for new and existing houses in any location in the United States, given the first three digits of its Zip code. Economic insulation levels are calculated for attics, cathedral ceilings, exterior walls, floors over unheated areas, slab floors, basement and crawlspace walls, ductwork in unconditioned spaces (attics and crawlspaces), and water heaters. Local climate data and default insulation costs and energy prices are retrieved from data files on the ZIP disk. The user can enter site-specific insulation costs, energy prices, heating and cooling system types and approximate efficiencies, and other parameters to customize the calculations for a specific house. ZIP was developed at the National Institute of Standards and Technology, under the sponsorship of the U.S. Department of Energy. ZIP and its supporting data files are provided on diskette for use with microcomputers having an MS-DOS operating system (typical IBM-PC/XT/AT and compatible systems).
Thermal Measurement of In-Situ and Thin-Specimen Aging of Experimental Polyisocyanurate Roof Insulation Foamed with Alternative Blowing Agents
Authors: Christian JE , Courville GE , Graves RS , Linkous RL , McElroy DL , Weaver FJ , Yarbrough DW
Published: March 2009

This paper reports apparent thermal conductivity (k) values from field and laboratory aging tests on a set of industry-produced, experimental polyisocyanurate (PIR) laminated boardstock foamed with hydrochlorofluorocarbons (HCFCs) as alternatives to chlorofluorocarbons (CFCs). The PIR boards were blown with five gases: CFC-11, HCFC-123, HCFC-141b, and 50/50 and 65/35 blends of HCFC-123/ HCFC-141b.

The k-values were determined at mean temperatures from 0 to 50°C (30 to 120°F) using techniques that meet ASTM C 1114 (Thin Heater Apparatus) and ASTM C 518 (Heat Flow Meter Apparatus) test methods. Results on laminate boards with facers provide an independent laboratory check on the increase in k observed for field exposure in the ORNL Roof Thermal Research Apparatus (RTRA). The observed laboratory increase in k was between 8% and 11% for all three blowing agent foams for a 240 day field exposure in the RTRA.

A thin-specimen aging procedure established the long-term thermal resistance of gas-filled foams. Thin specimens were planed from the industry-produced boardstock foams and aged at 24 and 65°C for up to 300 days.

An exponential dependency of k with the quantity (diffusion coefficient X time)½/thickness, provided effective diffusion coefficients for air components into the foams and blowing agent out of the foams. The foams blown with alternative blowing agents exhibited k-values 8 to 16% (average 12.7%) above CFC-11 foams under similar conditions.

Field exposures were conducted on specimens under single ply EPDM membranes in the RTRA for over 400 days. Hourly averages of panel temperature and heat flux were analyzed to obtain k as a function of mean temperature on a week by week basis. The k-values derived from the field data provided effective diffusion coefficients for air components in the foam, which were greater than those obtained from the thin-specimen aging procedure at 24°C by 20 to 70%, but were less than the 65°C aging values by 20 to 80%.

The relative performance of test specimens of HCFC-141b under a black and under a white membrane is reported. The field data suggests that the percent increase in k over that of the foam blown with CFC-11 is, after one year of aging, 4.3% for HCFC-123 and 10.2% for HCFC-141b. This leads to the same ordering of foams as derived from the thin-specimen analysis.
Some Factors Affecting the Long-Term Thermal Insulating Performance of Extruded Polystyrene Foams
Authors: Booth JR
Published: March 2009

The long-term thermal performance of insulation products is important to ensure their suitability in applications where product life can be fifty years or more. Actual measurements of foams aged under conditions of use are helpful but can only be gathered in real time. While necessary to assure the validity of model predictions, such measurements do not allow early determination of the future performance of new systems. With the need for all users of CFCs to find alternatives, the question of how to ensure long-term thermal performance takes on immediate significance. In this paper we describe some work done in our laboratory to assure the long-term thermal performance of STYROFOAM* brand insulation foam.

The use of bundles of thin-sliced foam samples provides a technique for accelerating foam aging. Aging curves relating bundle k-factor to a scaled age consolidates the data for measurement of the slope of k-factor with scaled age. This slope can be employed to evaluate the effective diffusion coefficients of candidate CFC replacements in polystyrene foams. The ratio of effective diffusion coefficient to film diffusion coefficient yields insight concerning the cell structure of the foam.
CFC Blowing Agents Substitutes — A Status Report
Authors: Zwolinski LM , Knopeck GM , Shankland IR
Published: March 2009

Rapidly moving events at the national and global levels mean a virtual elimination of chlorofluorocarbons (CFC) as insulation foam blowing agents by the year 2000. There have been a number of more environmentally acceptable substitutes proposed for CFCs. As replacements for CFC-11, HCFC-123 and 141b have received most attention, while HCFC-22 and HFC-134a have been considered as CFC-12 substitutes.

This paper reports on the progress made to critically evaluate these substitute materials in rigid polyurethane and polyisocyanurate insulating foams. The processing, industrial hygiene, and final foam performance of the substitutes are emphasized. The path to commercialization of HCFC-141b is presented in some detail.
A Review of Techniques for Improved Foam Conductivity: Reducing Radiation Heat Transfer, Limiting Aging and Inclusion of Vacuum Elements
Authors: Glicksman LR , Burke M , Marge A , Mozgowiec M
Published: March 2009

To comply with international agreement closed cell polyurethane and polyisocyanerate foams must be made with blowing agents which minimize ozone depletion in the stratosphere. Candidate blowing agents have higher vapor conductivities resulting in lower R values for the foams. This paper reviews recent results of research at M.I.T. sponsored by the Department of Energy and the Environmental Protection Agency to find means to recover high R values. Use of small opaque particles or smaller foam cells reduces the radiative transfer in foams which is usually one third of the total heat transfer at standard conditions. The thermal aging of foams made with new blowing agents is a function of the permeability which has been measured for several new materials. The rate of aging can be reduced by proper use of diffusion barriers on the foam surface. The inclusion of vacuum elements in foam should increase the overall R value. A key problem is to find packaging materials for the vacuum elements which preserve the vacuum over the insulation life while not causing substantial secondary heat transfer around the circumference of the element.
The Effect of Natural Convective Air Flows in Residential Attics on Ceiling Insulating Materials
Authors: Rose WB , McCaa DJ
Published: March 2009

Four test cells of a field laboratory have been used to determine the effect of natural convection on the thermal performance of insulating materials in various typical flat-ceiling residential attic constructions. Both blanket and loose fill mineral insulating materials are used in both vented and unvented assemblies. Temperature, air movement, heat flux and air humidity are continuously measured in each cell, and outdoor weather conditions are monitored. For the purpose of this study, data from the month of January 1991 are used; during that period the attic temperature remained colder than the “indoor” temperature. Field measurements of temperature at the top and bottom of the insulation, and heat flux measurements, are used to determine temperature difference across the insulation and instantaneous R-value. The results show that attic ventilation has negligible impact on the thermal performance of blanket insulation. The results also show an effect of elevated wintertime temperature differences upon loose-fill insulating materials.
Reduction of High Temperature Thermal Conductivity of Thin-Wall Ceramic Spheres
Authors: Chapman AT , Cochran JK , Ford TR , Furlong SD , McElroy DL
Published: March 2009

Within the last five years, a method for fabricating millimeter sized thin-wall hollow spheres from conventional powders has been developed at Georgia Tech. On firing, the spheres develop good strength as the walls are sintered to near theoretical density. These spheres have reasonably low thermal conductivities at low temperatures but conduction increases more rapidly than desired with increasing temperature due to transparency of the sphere wall. This work presents the results of opacification of the sphere walls with thermal pores to reduce the radiative component of conductivity at high temperatures. Mie scattering was employed in an effort to select an opacifying pore size distribution with a high thermal radiation scattering efficiency. It was shown that incorporation of pores in the micron size range could significantly reduce high temperature radiative conductivity.
Automated Low-Temperature Guarded Hot Plate for Measuring Apparent Conductivity
Authors: Smith DR , Dube' WP , Filla BJ
Published: March 2009

A guarded-hot-plate apparatus has been developed for measuring the apparent thermal conductivity of flat-slab thermal insulation materials at low temperatures. Relevant ranges of physical variables which can be accommodated (under different conditions) are: diameter, 203 mm (fixed); thickness, 5 to 30 mm; mean specimen temperatures, 100 to 400 K; temperature differences, 3 to 150 K; temperature gradients, 0.1 to 10 K/mm; and thermal resistance, 0.02 to 1.5 K·m2/W. Conductivity can be measured in dry air, gaseous nitrogen, helium, argon, or neon, or in vacuum. Apparent conductivity of an insulation material can be studied as a function of temperature, fill-gas pressure, or species, giving insight into the heat-transfer processes present in the material. Control of the main heater may be stabilized either at constant heater power or constant heater temperature. This apparatus will be useful in development of low-temperature Standard Reference Materials, and is being used to study heat transfer in closed-cell foam insulation containing HCFC blowing agents.
Underground Cellular Glass Pipe Insulation Failures in Quebec and Louisiana
Authors: Lotz WA
Published: March 2009

The author has participated as an expert witness on two major failures of the subject insulation on steam/condensate piping. One installation was in Quebec and one installation was in central Louisiana. The two systems were very different in design and installation. In both cases the water table was occasionally above the pipes. The soil in Louisiana was clay. There were no expansion nor anchoring provisions. The water-proofing consisted of multi-layers of cutback asphalt mastic and glass mesh reinforcing. The solution was to relocate the piping above ground. The soil in Quebec was clay except that the piping was in sand fill or a sand trench. There were many drainage ditches on the site — some of which were well below the level of the pipes. Dewatering pumps were installed in the trench in an attempt to save the insulation. The waterproofing system was designed and installed in strict accordance with the manufacturer's directions and under the supervision of the manufacturer's technical service representative.
Tensile Testing of EIFS Laminas
Authors: Flanders SN , Lampo RG , Davies AG
Published: March 2009

Information about tensile properties of exterior insulation finish system (EIFS) laminas has been unavailable to the engineering profession. Knowledge of the tensile properties of the reinforced laminas over the exterior surface of the insulation is key to 1) comparing EIFS performance and 2) establishing rules for spacing expansion and control joints in EIFSs for different thicknesses in different climates. This is a report that 1) establishes a procedure for tensile tests that may become an ASTM standard and 2) presents first-cut results on a variety of EIFS laminas, presented generically and anonymously. The paper discusses the results in detail and discusses what remains to be done to establish design guidelines for expansion and control joints in EIFS applications.
Experience with the Use of the New ASTM E 813-87
Authors: Van Der Sluys WA , Wade CS
Published: March 2009

In this paper the impact of recent changes in ASTM Test Method for JIc, a Measure of Fracture Toughness (E 813) are evaluated. JIc was determined from a large number of J-R curves using both the 1981 and the 1987 versions of ASTM E 813. The value of JIc is usually from 10 to 15% higher when measured according to the new version of the standard. The scatter in the measured JIc values was not affected by the revisions. Although the revisions to the standard removed a number of difficulties with its use, one problem still remains to be resolved. ASTM E 813 should be revised to include some guidance for correcting a0 so that the blunting line fits the data in the early portion of the J-R curve when a J-R curve from ASTM Test Method for Determining J-R Curves (E 1152-87) is used.
Normalization: An Experimental Method for Developing J-R Curves
Authors: Zhou Z , Lee K , Herrera R , Landes JD
Published: March 2009

The method of normalization has been used to develop J-R curves for metallic materials based only on analysis of load and displacement pairs in a ductile fracture test record. This method eliminates the need for crack length monitoring equipment. It not only provides a method for more easily conducting and evaluating J-R curve tests; but it could be useful for tests conducted under special conditions such as under dynamic loading, in restructive facilities such as a hot cell, or even in a facility with limited instrumentation.

The method uses a normalized deformation curve which has a functional relationship resembling a power law in the beginning and a straight line later. A functional form is proposed to fit this material deformation pattern. This form was used along with the load versus displacement records to evaluate J-R curves for many materials. The results showed that the new method was a more accurate and versatile one for the assessment of the J-R curve. Compared with previous application of this method, the accuracy is remarkably improved in the beginning stages of the J-R curve where a JIc point is determined. The JIc point was analyzed on more than 60 specimens and found to be consistent with methods used in the ASTM test standards.
Specimen Size Requirements for Elastic-Plastic Crack Growth Resistance Curves
Authors: Gordon JR , Jones RL
Published: March 2009

This paper presents the results of an experimental program to study size and geometry effects in CTOD R-curves. The results were obtained from room temperature unloading compliance R-curve tests on different sized single-edge-notch bend (SENB) specimens made from HY100 steel. The crack growth resistance was measured in terms of conventional CTOD, δo, (that is, as defined in BS 5762), CTOD corrected for crack growth, δR, and CTOD derived using a double clip gage arrangement δdc. It was found that all the CTOD R-curves exhibited upswings after crack extensions corresponding to approximately 17% of the initial uncracked ligament. Moreover, the slope of the CTOD R-curve increased dramatically after crack extensions corresponding to approximately 45% of the initial ligament. Apart from the R-curves obtained from the smaller specimens, normalizing the crack growth axis by dividing the crack extension by the initial ligament resulted in normalized CTOD R-curves which were in reasonable agreement over the entire crack growth range studied (that is, 60% of the initial uncracked ligament).
Obtaining J-Resistance Curves Using the Key-Curve and Elastic Unloading Compliance Methods: An Integrity Assessment Study
Authors: John SJ
Published: March 2009

The increasing use of J-resistance curves in design and ductile instability has inspired the need for a detailed and, indeed, reliable determination scheme for such curves. The basis for this paper emerged as part of a study of size effects on J-resistance curves. The three-part presentation includes descriptive sections for both the elastic unloading compliance and the key-curve methods, with the third part forming a comparative study of both procedures. Three-point bend specimens were used for testing the unloading compliance method using the crack mouth opening displacements for crack extension predictions. Using this specimen type, an empirically-based crack extension curvature correction procedure is introduced to correct crack length predictions for curved fronts. The load-line displacements were used for the crack tip energy evaluations with appropriate on-line corrections for indentation. The implementation of the key-curve method is reported and using compact tension specimens throughout, the results are compared to that of the elastic unloading compliance and the multiple specimen method. Finally, the virtues and drawbacks of both methods are compared and recommendations made. While the continuous nature of the key-curve method might be desirable for certain critical instability analyses, the justification of the experimental and numerical effort required is questioned.
Nonincremental Evaluation of Modified J-R Curve
Authors: Ohtsuka N
Published: March 2009

A method to calculate the deformation theory J, JD, which takes into account the influence of crack growth on J, and a modified version of the J-integral, JM, to allow a large relaxation of restrictions on the amount of crack extension and specimen configuration were proposed by Ernst et al. In this work, simple and nonincremental formulas for JD, JD, and crack extension, based on the single-specimen key-curve method using blunt U-notched specimens are proposed. The methods are applied to the determination of J-R curve for three-point bend type and compact tension type specimens. The accuracy of the methods in the determination of the J-R curves is discussed, emphasizing the differences between J-R curves for JD and JM.
Analysis of Deformation Behavior During Plastic Fracture
Authors: Hu JM , Albrecht P
Published: March 2009

The authors have previously shown that the cracks in compact tension specimen fabricated from A533B steel, HY80 steel, A710 steel, and CS19 aluminum extended at limit load. The present study examines the deformation behavior of C(T) specimens. The approach consists of deriving an equation for the plastic rotation factor, proposing an empirical equation for the plastic CTOD R-curve, and presenting the procedures for predicting the load versus load-line displacement curve with the plastic CTOD R-curve and limit load solution. The results obtained in this study lead to three important observations. First, many specimens that were reported by previous investigators to have failed in elastic-plastic fracture actually failed in plastic fracture. Second, a parameter based on plastic deformations at the crack tip, such as plastic CTOD, may better characterize the resistance to crack extension in plastic fracture. Third, for the fully plastic range of fracture behavior, the curve of load versus load-line displacement can be predicted knowing two material properties, the flow stress and the plastic CTOD R-curve.
Fracture Toughness and Fatigue Crack Initiation Tests of Welded Precipitation-Hardening Stainless Steel
Authors: Underwood JH , Farrara RA , O'Hara GP , Zalinka JJ , Senick JR
Published: March 2009

An analysis is described of a welded stainless steel box beam that experienced a structural failure during fatigue testing. Cracks initiated at notches caused by partial penetration welds and grew to a length of several centimetres in about 1000 load cycles.

The objective here is to describe the characterization of fracture toughness and fatigue crack initiation for the precipitation-hardening stainless steels used for the welds and parent plate of the beam. Three-point bend specimens were used to measure both fatigue crack initiation life and the J-integral fracture toughness of the parent plate and weld metal in various conditions. The notch fatigue analysis method of Barsom and Rolfe was used to analyze the crack initiation test results. The crack was grown further, side notches were added, and JIc tests were performed using ASTM Test Method for JIc, a Measure of Fracture Toughness (E 813-87) with a modified load-line-displacement unloading-compliance procedure to measure crack growth.

Conclusions drawn from the work include the following: (a) JIc can be accurately determined with a three-point bend test using load-line displacement to measure crack growth by unloading compliance (An accurate expression for a/W in terms of load-line displacement was developed.); and (b) fatigue crack initiation life and JIc fracture toughness of stainless steels in various conditions were characterized. The welded and aged condition, with no intermediate solution treatment, showed unstable, cleavage-type fracture and resulted in a low JIc value and a short initiation life.
Key-Curve Analysis of Linde 80 Welds
Authors: Yoon KK , Van Der Sluys WA , Lowe AL
Published: March 2009

Some reactor vessel weldments have relatively high copper contents that, when exposed to neutron irradiation, cause reductions in fracture toughness in the Charpy upper-shelf energy temperature region. To address this concern, a large number of both unirradiated and irradiated compact specimens were tested and the resulting J-resistance curves were generated. Key curves were developed from the load displacement records of single-specimen unloading compliance test data for magnesium-molybdenum-nickel/Linde 80 submerged-arc weld metals to study various aspects of toughness data behavior. In this paper, only a number of representative compact specimen tests are analyzed using the Herrera and Landes individual specimen key-curve approach to compare specimen size, temperature, and irradiation effects as part of a J-resistance model development effort for the Linde 80 class of weld metals.

The results of this study indicate (1) that the key-curve method works when applied to the Linde 80 type weld metals, (2) that a power law representation of the key curve provides a means to extract the Ramberg-Osgood exponent from the key curve if there are no available tensile data for the weld metal, and (3) that the irradiated specimens from both power reactors and a test reactor do not exhibit significant differences in comparable key-curve characteristics.
Observations in Conducting J-R Curve Tests on Nuclear Piping Materials
Authors: Marschall CW , Landow MP
Published: March 2009

This paper describes some of Battelle's experiences in developing J-R data for nuclear piping materials. Compact specimens were machined from both carbon steel and stainless steel pipe and subjected to testing at elevated temperatures, similar to temperatures encountered in nuclear reactor coolant piping. In many cases, the specimens displayed toughness levels above those considered valid by ASTM standard methods of testing. Furthermore, cracks were grown by about 50% of the original ligament, well in excess of the 10% limit imposed by ASTM Test Method for Determining J-R Curves (E 1152-87).

Topics discussed in the paper include: (1) monitoring crack extension using the direct-current electric potential method, (2) specimen thickness changes ahead of the growing crack, (3) observations of fracture appearance and crack growth direction in ferritic versus austenitic steels, (4) observations of ductile-crack jumps in carbon steels tested at 288°C (550°F), (5) unusual effects of partial unloadings in testing carbon steels at 288°C (550°F), and (6) difficulties with certain ASTM definitions in testing highly ductile materials.