bluuebunny/crossref_metadata_2025 huggingface dataset:
Glass Transition and Heat Capacities of Inorganic Glasses: Diminishing Change in the Heat Capacity at T
g for xNa2S + (1 − x)B2S3 Glasses
Authors: Kincs J , Cho J , Bloyer D , Martin SW
Published: March 2009

The Tg's and heat capacity functions have been measured for a series of Na2S + B2S3 glasses for the first time. Unlike the alkali borates, Tg decreases rapidly as Na2S is added to B2S3. This effect, even in the presence of a rapidly increasing fraction of tetrahedrally coordinated borons, has been associated with the “over crosslinking” effect of the sulfide ion. Unlike the borate glasses where each added oxygen produces two tetrahedral borons, the conversion rate for the thioborates is between four and six. This behavior is suggested to result in the formation of local tightly-bonded molecular-like structures that exhibit less long-range network bonding than the alkali borate glasses. As a result, Tg decreases with added alkali in alkali thioborates rather than increases as in the alkali borate glasses.

The change in heat capacity at Tg, ΔCp(Tg) has been carefully measured and is found to also decrease dramatically as alkali sulfide is added to the glass. Again this effect is opposite to the trends observed for the alkali borate glasses. The decreasing ΔCp(Tg) occurs even in the presence of a decreasing Tg. We have tentatively associated the diminishing ΔCp(Tg) values to the decreasing density of the configurational states above Tg. This is attributed to the high coordination number and site specificity caused by the added alkali sulfide. The glassy state heat capacities were analyzed and found to reach ˜90% of the classical limiting DuLong-Petit value just below Tg for all glasses. This was used to suggest that the diminishing ΔCp(Tg) values are associated with a unique behavior in the system to become a liquid with very little change in the density of configurational states.
Glass Transition of a Liquid Crystal Polymer
Authors: Cassel B , Riga AT
Published: March 2009

A commercially available liquid crystal polymer system having a very weak glass transition is investigated in order to illustrate the special problems of measurement and interpretation inherent in high-sensitivity Tg measurement. Differential scanning calorimetry, thermomechanical analysis, and dynamic mechanical analysis were employed over the temperature region from ambient to 175°C. A transition between 75 and 125°C with a midpoint around 100°C was detected by most techniques. The use of the maximum in the derivative of the measured signal as the primary assignment of the glass transition temperature is recommended. The results are discussed with reference to other literature on this polymer system.
Measurement of the Glass Transition Temperature of Elastomer Systems
Authors: Sircar AK , Chartoff RP
Published: March 2009

The glass transition temperature of polymers depends on both the experimental procedures and the experimental techniques used for its evaluation. However, the value of the published data is often diminished because these details are omitted. Examples are cited to show how the magnitude of differential scanning calorimetry (DSC) Tg depends on the Tg location and different calibration methods. Some comments are also made about thermomechanical analysis (TMA) and dynamic mechanical analysis (DMA) methods, although these are treated only briefly.

The factors that are unique to elastomer glass transition temperatures are: (1) the difficulties of calibration of the instruments at subambient temperature, (2) increase of Tg by the extent of vulcanization and filler loading, (3) differences due to microstructure and microphase separation, and (4) the availability of different grades of the same elastomer with different composition or added components, which alter their Tg. Thus, the literature value of Tg should include not only the calibration and procedure for the experiment, but also the exact name and description of the elastomer with the number index, the recipe used, and the cure conditions.
Glass Transition Measurements on Automotive Coatings by DSC, DMA, and TMA
Authors: Gupta MK
Published: March 2009

The glass transition temperature (Tg) is a very useful parameter that characterizes the temperature dependence of the physical and mechanical properties of coatings. Differential scanning calorimetry (DSC), thermomechanical analysis (TMA), and dynamical mechanical analysis (DMA) were used to determine the Tg of automotive coatings.

DMA analyses were done on coatings deposited on a steel substrate in the fixed frequency mode, at frequencies of 0.01, 0.1, 1.0, and 10 Hz. Specimens were heated in either step mode (2°C) or ramp mode (5°C/min). TMA analyses were done either on coatings deposited on steel substrate or on free films at 5°C/min. DSC analyses were done at 5°C/min either on free films or on specimens that were sanded out from steel panel. Indium metal was used for the temperature calibration of DSC, TMA, and DMA. For one-coat films, the correlation between the temperature of midpoint in DSC, the onset temperature of penetration by TMA, and the onset temperature of loss modulus by DMA at 0.1 Hz was good. However, for multicoat films the Tg's for individual layers were visible only if their Tg's were far apart. It was possible in some cases to remove the top layer by scraping and analyzing the residual layers. The use of DSC, DMA, and TMA to determine the Tg's of different automotive coatings on metal substrate has been demonstrated, which is very useful in research and development, and problem solving.
Video Recording of Spontaneous Falls of the Elderly
Authors: Holliday PJ , Fernie GR , Gryfe CI , Griggs GT
Published: March 2009

Falls and unsteadiness of gait are major problems faced by many elderly people. With the exception of some stairway accidents, there are no actual recordings of falls of elderly people. A recording system consisting of four video cameras and five videotape recorders, controlled by a computer, was used to continuously monitor activity in the lobby of a geriatric complex. Whenever a fall occurred all of the tape drives were stopped. The video record of the fall was subjected to an analysis by a multidisciplinary team. During the 15 months of surveillance, 25 falls by 17 persons were recorded on videotape. Nine men and eight women fell. The average age of the persons who fell was 81.1 years. Three quarters of the falls occurred in the elevator lobby of the geriatric complex. The causes of falls, as observed from the videotapes, are complex. Based on the videotape of the fall, the falls could be classified generally into those where the predominant factor was due to environmental or external conditions (N = 9 or 36%), behavioral factors (N = 1), or intrinsic factors (N = 15 or 60%). The ability to repeatedly examine falls is of value to scientists, educators, architects, administrators of geriatric facilities, and others involved in risk control for health and safety.
The Biomedical and Environmental Characteristics of Slips, Stumbles, and Falls in the Elderly
Authors: Tideiksaar R
Published: March 2009

Falls represent an important and critical event for older persons. Falls due to trips, slips, and stumbles occur during the stance and swing phase of the gait cycle. They are initiated by a combination of intrinsic and extrinsic events. Intrinsic causes include age-related declines in visual, vestibular, proprioceptive, and musculoskeletal function. Extrinsic factors encompass environmental obstacles associated with foot-ground contact.

The purpose of this study was twofold: (1) to determine, in a group of older persons with multiple trip and slip falls, the underlying intrinsic and extrinsic factor responsible, and (2) to investigate whether medical and environmental intervention would reduce falls. Twenty-five older persons were examined. They experienced a total of 102 falls; 75% due to slips, and 25% the result of trips. Intrinsic abnormalities of the gait cycle (Parkinsonism and peripheral neuropathy) and decreased vision due to cataracts, in combination with extrinsic or environmental foot-ground conditions (that is, low-frictional resistant or irregular ground surfaces) were found to be the leading cause of slips and trips.

A one-year follow-up, after medical and environmental interventions, showed that fourteen persons experienced no additional falls, nine continued to fall, but less frequently, and two persons continued to fall as often as before.
Experimental Determination of Limiting and Sliding Friction Forces for Purposes of Modeling Slips, Stumbles, and Falls
Authors: Francis PR , Zozula CA
Published: March 2009

Estimates of the coefficients of limiting and sliding friction for two selected shoes and two pedestrian surfaces were obtained from two separate procedures. Data generated from a procedure in which a weighted shoe was pulled across the surfaces were compared with data generated from a subject wearing the same shoes who performed a sliding maneuver on the surfaces. The sliding maneuver produced a wider range of loading conditions and consistently higher values of the coefficients of friction than the pulling tests. It was concluded that the magnitudes of coefficients of friction vary with the rate of loading. Values of the coefficients of friction showed variability from one trial to the next under each loading condition examined. Therefore it is recommended that empirically determined estimates of coefficients of friction should include some measure of variability.
Defense: Slip, Stumble, and Fall Accidents
Authors: Rutledge AD
Published: March 2009

The cost of accidents has escalated to a point which prompted voter initiatives appearing on ballots during 1988 and 1989. To date, court rulings appear to look favorably upon voter choice. This paper describes the effect of the new litigation on the defense of slip, stumble, and fall (SSAF) accidents. It sets forth high-technology and engineering procedures which provide for a more equitable cost distribution for those cases wherein joint liability exists. High-technology investigative procedures are described which provide a technically valid foundation for the claims evaluator and attorney during settlement negotiations. Innovative graphics are produced with proper foundation as a by-product of the high-technology investigative procedures. Set forth in outline form is the necessary additional background knowledge required by both claims evaluator and trial attorney for suggested implementation of the proposed system. A sample case is presented.
Frictional and Ground Reaction Force Measurement with the Multicomponent Quartz Force Plate
Authors: Schieb DA , Lochocki RF , Gautschi GH
Published: March 2009

Accurate measurement of ground reaction forces (GRF) are an essential prerequisite to understanding the nature and locomotion response mechanisms of complex slip and fall situations. Significant shortcomings have been reported with many devices currently used to measure static and dynamic frictional loads. This paper describes performance characteristics of the multicomponent quartz piezoelectric force plate (FP) which has been used successfully over two decades for various biomechanical measurements including materials and impact testing, shoe/surface study, and frictional and GRF testing.
Data Acquisition and Software for the Multicomponent Piezoelectric Force Plate
Authors: Schieb DA
Published: March 2009

For frictional and GRF data measurement using a multicomponent quartz piezoelectric force plate (FP), certain hardware, and recording procedures should be met to obtain accurate data acquisition, reduction, and analysis. This paper describes quartz FP data acquisition and development of a PC-AT based software/hardware system for use in gait, slip, and fall, and frictional assessment.
Lower-Bound Initiation Toughness of A533-B Reactor-Grade Steel
Authors: Irwin GR , Dally JW , Zhang X-J , Bonenberger RJ
Published: March 2009

The lower-bound initiation toughness of A533-B reactor-grade steel was determined over the temperature range from 3 to 50°C. The toughness of the steel was depressed toward the lower-bound value by using the following testing procedures: (1) dynamic loading, (2) notched-round-bar specimens, and (3) axial precompression of the notch. The paper describes in detail the method of applying the impact load to the specimen, the method of precompressing the specimens, and the testing procedure. The dynamic initiation toughness, KId, which correlates with the lower-bound toughness, was determined from analysis of the strain-time behavior of the specimens. Also, the results from a fractographic analysis were correlated with those from the straintime analysis. The lower-bound toughness from this study compared favorably with KIa and KId data established through more extensive testing programs.
Cleavage Fracture Under Short Stress Pulse Loading at Low Temperature
Authors: Homma H , Kanto Y , Tanaka K
Published: March 2009

Cracks in SM50A steel for welding structure, chilled to 233 and 193K, were loaded by various stress intensity pulses with durations of 20, 40, and 80 μs to generate experimental data of critical stress intensity levels for crack instability. Fracture surfaces were observed by a scanning electron microscope to examine cleavage nucleation origins ahead of the crack tips. The experimental results are discussed in terms of minimum time criterion and dislocation dynamics.

The critical stress intensity obtained by the minimum time criterion was higher at 233K than at 193K, whereas the minimum time was shorter at 233K. The cleavage nucleation origin approached the crack tip as the temperature decreased. Finally, the temperature dependence of the minimum time was interpreted by the dislocation dynamics.
A Procedure for Drop-Tower Testing of Shallow-Cracked, Single-Edge Notched Bend Specimens
Authors: Kirk MT , Waskey JP , Dodds RH
Published: March 2009

Unacceptably pessimistic predictions of structural reserve capacity often result from the use of conventional initiation fracture-toughness values (for example, JIc, δc) measured using deeply cracked bend specimens. Conversely, favorable comparison between predictions and structural fracture behavior have been reported when the predictions are based on toughness values measured in such a manner that the crack-tip constraint and the loading rate closely match those experienced in service. As a result, considerable attention has been paid recently to the elevated fracture initiation resistance of cracks shallower than the 0.45 to 0.75 crack length/width (a/W) used in standardized tests. However, standardized procedures for estimating the fracture initiation resistance of shallow cracks, particularly at the high loading rates characteristic of certain severe service conditions, have yet to be developed. In this investigation, techniques useful for estimating the load, load-line displacement, and the time of crack initiation during impact tests of single-edge notched bend specimens having shallow fatigue cracks (a/ W ≈ 0.1) were developed and validated. The bending stress distribution across the specimen midway between the support and loading points, determined based on strain measurements and a uniaxial stress-strain relationship, was used to estimate the load imparted to the specimen by the impactor. Load-line displacement was estimated using four noncontacting transducers positioned along the underside of the bend specimen, whereas the time of crack initiation was inferred from strain readings taken from the elastically loaded region behind the fatigue crack tip. The applicability of these procedures was demonstrated at an impact loading rate of 4.88 m/s, whereas control experiments at quasi-static loading rates were used to demonstrate the accuracy of these new procedures for both low- and high-strain-hardening steel alloys.
Mechanical Reduction of Inertially Generated Effects in Single-Edge Notched Bend (SENB) Specimens Subjected to Impact Loading
Authors: KarisAllen KJ , Morrison J
Published: March 2009

Two novel mechanical techniques are described for reducing the magnitude of the inertial component of dynamic load/time records while maintaining a high specimen velocity response. One approach uses a load-line plastic absorber to inhibit the oscillation from establishing itself; the second uses precompressed wing absorbers to reduce selectively the amplitude of the load oscillations commonly associated with inertial energy transfer. Both systems independently generate load-time records in which the magnitude of the oscillations is greatly reduced without a significant change in vibration frequency. The load-line also reduces the magnitude of the initial tup load spike commonly associated with impact testing. The data indicate that the use of these absorbers does not introduce any extraneous effects in the dynamic load/time records and that maximum damping can be obtained by combining the two techniques. The elastic portion of the dynamic and static load/displacement data also shows a good correlation.
Dynamic Fracture Toughness of Ductile Iron
Authors: McConnell P
Published: March 2009

Dynamic J-integral fracture-toughness test results were obtained for several different ductile irons over a range of temperatures. The ductile irons were all of a chemistry and microstructure in nominal compliance with ASTM Specification for Ferritic Ductile Iron Suitable for Low Temperature Service (A 874).

Among the materials investigated were ductile irons from actual nuclear spent-fuel storage casks and from a cask to be used in a drop-test program at a national laboratory. These ductile irons were of a mainly ferritic matrix with highly spherical graphite nodules. The tests were performed over a range of temperatures in an attempt to define the dynamic fracture-toughness transition temperature regime, important because the service temperature for transport casks for “normal” conditions can be as low as −40°C.

The technique employed for measuring the dynamic J-integral value was based on the multiplespecimen technique described in ASTM Test for JIc, a Measure of Fracture Toughness (E 813). Details of the test technique are discussed.

The upper-shelf dynamic fracture-toughness values for the three ductile irons investigated were similar, ranging from 61 to 77 MPa∙m½ at room temperature.

The transition between upper-shelf and lower-shelf dynamic fracture toughness occurred over the range of approximately -35 to -50°C for one ductile iron and the range of -50 to -68°C for another. These transition temperature regimes were higher than the quasi-static transition temperature noted for similar ductile iron material.

The influence of microstructure on the fracture toughness of ductile iron is discussed.
Crack-Arrest and Static Fracture Toughness Tests of a Ship Plate Steel
Authors: Underwood JH , Burch IA , Ritter JC
Published: March 2009

The recently standardized ASTM Test for Determining the Plane-Strain Crack Arrest Fracture Toughness KIa of Ferritic Steels (E 1221) was modified for use with BIS 690 steel, an Australian low-alloy, 700-MPa strength, quenched and tempered steel used for ship plate. Specimens of 50-mm thickness in longitudinal and transverse orientations were tested at -60°C with various depths of side groove. Specimen configurations somewhat outside the range of ASTM Test E 1221 were found to be useful for this steel and were suggested as modifications to the standard method. A different solution and expression for stress intensity factor were used to evaluate the tests and to develop a method for predicting the crack length at which a running crack will arrest. Good agreement was obtained between the observed and predicted crack lengths at arrest.

The wedge-loading arrangement of the crack-arrest test procedure was used for static fracture toughness tests. Procedures for static wedge-loading fracture toughness were proposed, particularly for comparisons with crack-arrest toughness test results obtained under similar test conditions. for the tests here, the static fracture toughness was more than twice the value of crack-arrest toughness.
The Development of Standard Methods for Determining the Dynamic Fracture Toughness of Metallic Materials
Authors: MacGillivray HJ , Cannon DF
Published: March 2009

A simple, reliable, and repeatable method has been developed for determining dynamic plane-strain fracture toughness using an on-specimen strain gage. This extends the range of the British Standard Method for Determination of the Dynamic Fracture Toughness of Metallic Materials (BS 6729) to include measurement at impact testing rates. Dynamic finite element computing was used to optimize the position of the gage on the specimen. In tests at low loading rates on Charpy specimens, good agreement was found between toughness values calculated from the applied load and the calibrated gage, and with those measured by the shadow optic caustic technique. At higher rates, several gage types and two adhesives were compared. A satisfactory method was developed for performing tests at high and low temperatures. The technique was applied to larger bend specimens of two steels, and a test program was conducted at seven laboratories to assess the influence of testing machine and instrumentation variables. From the results, a standard calibration and test procedure has been developed.
Comparison of High Calcium, Soft Burned Dolomitic and Hard Burned Dolomitic Quicklimes for Soil Stabilization Use
Authors: Oliphant JL , Walker DD
Published: March 2009

A locally available clay, with an initial plasticity index of 63, was treated with high calcium, and soft and hard burned dolomitic quicklimes. The amount required for treatment was determined, using the Eades-Grimm pH test, to be 3 % for the high calcium quicklime, and 5 % for both the soft and hard burned dolomitic quicklimes. CBR (California bearing ratio) swelling and penetration tests were run on treated clay samples. The high calcium quicklime treated sample swelled 0.45 % while the soft and hard burned dolomitic quicklime treated samples swelled 1.2 and 1.3 % respectively. The CBR values were 65 for the high calcium sample and 60 and 56 for the soft and hard burned dolomitic samples.

Several tests were done to measure reaction rates of quicklime with the clay. The high calcium and soft burned dolomitic quicklimes reacted rapidly while the hard burned quicklime was somewhat slower.

A mathematical equation has been developed that defines the relationship of pH to quicklime dosage more accurately than the Eades-Grimm test method.

Temperature of the solutions at the time of the pH measurements can have a significant affect on the amount of lime required for stabilization. One illustration shows that the dosage of quicklime, as determined by the Eades-Grimm test method, could be in error by as much as 250 %.
The Porta Batch Lime Slurry Method
Authors: McKennon JT
Published: March 2009

Many new methods of application have been tried as a result of the rapid growth of soil stabilization with lime. Mixing lime with water, prior to application, has become the predominant method of application because of environmental concerns over dust from both hydrated and quicklime.

With the slurrying of lime, prior to application, becoming the preferred method of application, the hunt for a mixing method, which is both economical and effective, has resulted in the development of the Porta Batch lime slaking system. This batch method converts truckload quantities of quicklime into hydrated lime slurry at the jobsite.

The saving of 10 to 15 % of the cost of the lime by converting quicklime into hydrated lime slurry at the jobsite has resulted in the rapid growth of the Porta Batch system in the U.S. In the last 6 to 8 years, dozens of major jobs (where clay soil dictates the use of lime) have been done by this method.

Research has now shown an added benefit of the Porta Batch method. The unique qualities of the patented mixing system combine to produce a lime slurry that is superior in many ways to dry hydrated lime mixed with water. The benefits include higher surface area, elevated temperature slurry for more rapid curing in the soil, and a more uniform homogeneous slurry mixture resulting in more uniform job results.
Gas Reburning—Sorbent Injection for the Control of Acid Rain Precursors from Coal Fired Utility Boilers
Authors: Folsom BA , Bartok W
Published: March 2009

Gas reburning-sorbent injection (GR-SI) is an emissions control technology for coal fired power plants which uses natural gas and calcium sorbents to reduce NOx and sulfur dioxide (SO2) emissions by 60 and 50 %, respectively. Gas reburning involves injecting natural gas into the boiler and reduces NOx by reactions involving hydrocarbon fragments produced in the process. SO2 is reduced since natural gas contains no sulfur. Additional SO2 reduction is provided by injection of a calcium based sorbent into the boiler furnace or downstream. The sorbent reacts with SO2 to produce calcium sulfate (CaSO4) which is captured by existing particulate collection equipment at the plant.

The preferred sorbent for GR-SI is calcium hydroxide [Ca(OH)2]. GR-SI requires substantial quantities of sorbent and will thus produce a significant market for calcium products.

A field evaluation of GR-SI is now in progress on two boilers in Illinois. The design engineering has been completed and construction is in progress. Start-up is scheduled for fall 1990.

This paper presents an overview of the GR-SI technology and the field evaluation project. Implications for the lime industry are also discussed.
FGD System Conversion
Authors: Blackford EA , Forsythe RC
Published: March 2009

This paper reports on the conversion of a soda-ash and lime dual-alkali flue gas desulfurization system (FGD) to a magnesium-enhanced lime process at Applied Energy Services' Beaver Valley Cogeneration Plant in Monaca, PA.

Burning approximately 500 000 tons 454 000 metric tons of medium sulfur coal per year in the plant's four boilers, with a total capacity of 125 MW, AES' Beaver Valley Cogeneration Plant supplies process steam used at the ARCO Chemical Co.'s Beaver Valley Plant, while also selling approximately 105 MW of electricity to West Penn Power Company. Equipped, in 1980, with a soda-ash and lime dual-alkali FGD system, the plant is required to meet the Pennsylvania Department of Environmental Resources 0.75 lb (0.3410 kg) SO2/MM Btu sulfur dioxide emission limit.
Lime and Pozzolans for Safe Usage of Waste Products
Authors: Minnick LJ
Published: March 2009

This document will review the developments relating to a number of projects utilizing lime and fly ash and other waste materials. It is intended to describe requirements and control in construction applications. Several ASTM standards, released in 1990, will be referenced in relation to these developments.
Use of Kiln Dust with Quicklime for Effective Municipal Sludge Pasteurization and Stabilization with the N-Viro Soil Process
Authors: Burnham JC , Hatfield N , Bennett GF , Logan TJ
Published: March 2009

A series of experiments has provided data which indicate that treatment of municipal wastewater sludge cakes with 35 % kiln dust (cement, CKD or lime, LKD), alone or with a small amount of quicklime, will reduce the pathogenic microbial population in the sludge to below the U.S. Environmental Protection Agency's (USEPA) Process to Further Reduce Pathogens (PFRP) standard (USEPA, 1989). Both laboratory and large-scale field tests show that maintaining treated sludge at 52°C for 12 h, while the pH exceeds 12.0, kills viable indigenous and seeded populations of salmonella, poliovirus, and ascaris ova.

The addition of the cement or lime kiln dust results in a granular, easy-to-handle, soil-like material that is then treated in one of two methods. In one alternative no heating is necessary, while in the other, sludge cake is heated to 52°C for 12 h. In both, the pH must exceed 12.0 for a defined period. After this, the alkaline treated sludge is air dried through intermittent turning of windrows.

These patented (N-Viro) and USEPA's PFRP-approved pasteurization processes leave approximately 106 indigenous microorganisms per 5 g dry weight sludge, which help maintain the treated sludge in a nearly odor-free, stable, soil-like form. The specific chemical and physical effects of cement and lime kiln dust on municipal sludge cakes are presented to explain the mechanisms of the pasteurization process. Sludges from over twenty cities have been processed to make N-Viro Soil and all of them have achieved the PFRP criteria.

This process helps to prevent metal release in leachate by fixing the heavy metals present in the product and converting them to insoluble metal hydroxides. Data will show the degree to which alkaline treatment renders insoluble the heavy metals present in sludge. The modified EP Tox test was used to quantify the metal fixation accomplished by the mixing of kiln dust and sludge.
Fatigue Testing of Femoral Hip Prostheses with a Two-Beam Simulated Femoral Bone Support Fixture
Authors: Humphrey SM , Gilbertson LN
Published: March 2009

Changes in the design philosophy for femoral hip implants are resulting in new cementless designs that attempt to increase bone strain levels by increasing stem flexibility. Composite materials are often selected for these new implants because of the inherent ability to custom design the mechanical response of the material. Traditional test methods currently used for the evaluation of relatively stiff, homogeneous metallic implants may not be appropriate for the evaluation of these new prosthesis designs.

This paper presents a new test fixture design that uses a two-beam structure to simulate the support provided in-vivo by the femoral bone. A prototype fixture was designed, built, and tested with composite hip prostheses to demonstrate the viability of the concept. Net head deflections and prosthesis strain levels were measured and compared to the response of the same implants when press fit and cemented in composite femurs.

Data from these tests suggest that such a fixture design is capable of providing the required support and endurance for high cycle prosthesis fatigue testing. The net support was greater than that of a press fit implant but less than that of a cemented implant in a composite bone. Simulation of the most extreme stress state for the implant is most likely represented by the press fit case and therefor some modifications of the fixture design will be required to improve the support model.
Creep Testing of a Composite Material Human Hip Prosthesis
Authors: Maharaj GR , Jamison RD
Published: March 2009

Composite materials are being investigated for use as replacements for metals in the femoral component of total hip arthroplasty with current interest being focused primarily on carbon fiber reinforced thermoplastics. Since a composite hip prosthesis will be a primary load bearing component in an aggressive in vivo environment for the lifetime of the patient, a time-dependent effect such as creep must be thoroughly characterized and is the focus of this paper.

Environmental flexural creep testing of two laminate designs of carbon fiber reinforced polyetheretherketone (C/PEEK) coupons at 207 MPa for 3 months resulted in a maximum creep strain of 226 μtstrain. After 3000 h at an equivalent in vivo load of 4000 N, two prototype C/PEEK hips with the same laminate designs as previously mentioned displayed 93 μm and 250 μm of creep.

In both the coupon and prototype hip study, the measured and predicted creep strains are an order of magnitude below the elastic strains that are themselves significantly lower than the strain to failure of this material. The results clearly indicate that the viscoelastic behavior of the composite hip is fiber dominated and is not expected to be a limiting factor in the long-term performance of a properly designed composite hip.
Stability of Polysulfone Composite Materials in a Lipid Environment
Authors: Salzstein RA , Moran JM
Published: March 2009

A study was conducted to determine if the performance of polysulfone/carbon fiber laminates is affected by lipids, as might be found in vivo. Stress-rupture testing of neat polysulfone showed that 100% soybean oil provided a more severe lipid environment than bone marrow. Fracture toughness, creep, and fatigue tests were chosen to study the influence of this lipid environment on the integrity of the laminates composed of polysulfone reinforced with carbon fiber. These tests evaluated the integrity of the composite material under extreme conditions. Based on the studies of this investigation, the following can be concluded; within the time periods examined in this study, lipid conditioning had no effect on the composite material performance in any of the tests.
Georgia Power Company Acoustic Emission Test Program
Authors: Bingham AH , Veal WC
Published: March 2009

Aerial personnel devices are common equipment in industry today. At an electrical utility, aerial devices are used to position personnel and equipment during line work. Periodic mechanical and electrical tests are necessary to determine the integrity of the boom structure. This paper contains a brief overview of the Georgia Power fleet and the acoustic emission test program. The actual mechanics of a day to day test program are discussed. The acoustic emission acceptance criteria used by Georgia Power for aerial devices is discussed, and actual test results are examined to show the test program benefits. Safety, reduced service intervals, and extended service life can be assured with an adequate testing program.
An Acoustic Emissions Testing Program
Authors: Largin CR , Colvin JE
Published: March 2009

Alabama Power Company started AE Testing in 1983, after suffering a catastrophic failure of a fiberglass boom. As with most new technology we felt some skepticism but were soon sold on this new method of listening inside the fiberglass components This paper will give the details of our testing program as it started and discuss the changes that have taken place over the past seven years. It will include statistics concerning the number of failures and the percentage of the fleet that failed (9% 1983, less than 1% 1990). The paper will discuss the improvement in the mechanics condition of our fleet as a direct result of the AE Testing Program as we see it. Included in the paper will be at least two case histories of booms that failed the AE Test and the final solution. It will also cover what we feel is the actual value of our AE Testing Program as it has not only given us a safer fleet but has also reduced our maintenance costs by detecting problems while they are in the early stages, allowing us to make minor repairs rather than finding the defects after they have developed into a major repair. Today we require that all new equipment pass an acoustic emission test prior to acceptance by us. By the use of acoustic emission testing we have been able to improve our preventive maintenance program with the focus on areas of concern. We know and understand more about the unique characteristics of fiberglass and steel components through the use of AE Testing.
Acoustic Emission Monitoring and Destructive Testing of Glass Fibre Reinforced Plastic Bucket Truck Booms
Authors: Gambone LR , Marusic H , Kung D , Janke G
Published: March 2009

The objectives of this study were to develop a larger data base on which to select acoustic emission (AE) criteria for predicting the serviceability of glass fibre reinforced plastic (GFRP) bucket truck booms and to determine the structural significance of visually detectable in-situ service defects such as cuts, cracks and impact damage. Six different GFRP booms which had been removed from service were mounted in cantilever and incrementally loaded to failure and periodically subjected to an ASTM F914 type test procedure. Data generated from the continuous monitoring of AE sensors mounted along the boom length included signal events, counts and amplitude. Felicity ratio and boom compliance were evaluated in order to obtain additional damage growth information.
Analysis of ASTM Round-Robin Results: Ae Sensors, Systems, Brands, and Calibration Rods
Authors: Ek CW
Published: March 2009

Round-robin evaluation of various acoustic emission (AE) sensors, systems, and brands were made using four calibration rods. The intent of the evaluation was to determine the suitability of using plastic rods as in situ system calibration check devices. The rods were made of clear acrylic, and were provided with milled flats by which to mount each sensor under test.

Data from five participants in the round robin evaluation shows that among the variables of rod number (4), sensor frequency (2), sensor brand (2), and AE system (5), the largest difference of peak amplitude AE signal was due to sensor frequency, with a coefficient of variation (COV) of 0.26. Differences in sensor resonant frequency are expected to result in large differences in signal characteristics. The remaining variables are ranked by decreasing magnitude of effect: sensor brand (0.11), AE system (0.10), and rod number (0.05). The COV's shown above are based on average signal peak amplitude from at least five lead break events from a 30 in. (76 cm) distance for each sensor-rod combination.

The paper includes data summaries and a discussion of sources which may have led to the observed variations. A conclusion is drawn indicating that the plastic rods are acceptable in situ system check devices. However, serious concern exists due to variations between AE systems and sensor brands. These variations may complicate the use of numerical standards or guidelines for AE test acceptance criteria.
Personnel Qualification and Certification for Acoustic Emission Testing of Aerial Devices
Authors: Pollock AA , Ternowchek SJ
Published: March 2009

The ASTM Standard Test Method for Acoustic Emission for Insulated Aerial Personnel Devices (F 914-85) requires personnel performing the method to be qualified consistent with SNT-TC-1A, a recommended practice of the American Society for Nondestructive Testing (ASNT). SNT-TC-1A provides recommendations for employer certification at three levels of responsibility, based on training, examinations and on-the-job experience.

This paper describes programs developed for two electric utilities for the qualification of their AE inspectors in accordance with F 914 requirements. Starting with a pre-existing General course and examination, Specific and Practical trainings and examinations were developed and delivered to candidate Level I and Level II personnel. This led to several AE inspectors being duly certified under their utility's in-house procedure for NDT personnel. A well documented test procedure proved to be an important prerequisite to the personnel qualification process. Practical examinations in AE proved to be best conducted in the context of a fullscale test of an actual aerial device.
Advances in AE Technology for Testing of Aerial Devices
Authors: Ternowchek SJ , Mitchell JR
Published: March 2009

As a tool for inspecting aerial devices, acoustic emission (AE), has gained wide popularity and is one of the preferred techniques to be used when performing safety inspections on these vehicles. Many utilities, truck manufacturers and independent testing companies rely on AE as a primary screening technique when evaluating vehicle integrity. AE testing has proven to be a valuable tool in determining structural integrity of both fiber-glass and metal components of the aerial device.
Alarms in an Operative Intensive Care Unit: Response of the Nursing Staff
Authors: Deller A , Konrad F , Kilian J , Schühle B
Published: March 2009

In a prospective study the present state of alarming by medical devices in an operative intensive care unit of a 1000 bed university hospital was recorded including the responses of the nursing staff. On a multiphase base over 190 h 2041 alarms released by 18 different alarm releasing medicotechnical devices were registrated, indicating an emergency condition in 24 cases (1%), 1345 times (66%) a warning, and in 672 cases a false alarm as judged from the view after. The mean interval between two alarms was 5½ min.

Inadequate adjustment of tolerance limits for alarm activation was found in all groups of medicotechnical devices. Switch on/off keys of alarms might better be replaced by muting buttons, which silence the signal and reactivate it spontaneous after 1 min.

The response of the attendants to the alarm signals was immediate in 94% of all alarms and a delay of more than 2 min in 1% was interpreted as missing. The first response was alarm related in most instances.

We conclude that the number of alarm devices in medicotechnical equipment should be reduced although the present state revealed effective in anticipatory warning in most conditions before the patient's physiologic parameters were concerned.
Influence of Special Consumer Groups as a Subset of Respondents on the Outcomes of Consumer Acceptance Tests
Authors: Lundahl DS
Published: March 2009

Statistical modeling was applied to determine the influence of special consumer groups as a small subset (10 to 30%) of respondents on the outcomes of consumer tests. Tables are displayed for standard deviations ranging from 1.0 to 2.0 where a special consumer group displays a differing hedonic response pattern from the general consumer population. Without segmenting by the special consumer group in the design and analysis, situations are identified (i.e., number of respondents, type I error, standard deviations and proportion of special consumers) where a crossover interaction greatly increases the chances for a type II error (i.e., missing true differences). When special consumers are a minority segment accepting one product over another, a small proportion of special consumers can greatly increase the power to conclude significance. Without segmenting in the design and analysis, minority acceptance can increase the chances for a type I error, i.e., falsely concluding that the general consumer population accepts one product over the other. As the total number of respondents increases, the smaller the proportion of minority acceptors needed to draw a conclusion with a type I error.

Testing strategies are presented to segment on the basis of special consumer groups to guard against the chances for type I or II errors. In addition, if a special consumer group responds differently from the general population, methods are presented to determine how the special consumer group differed. Strategies are discussed for randomized complete block and balanced incomplete block test designs.
French- and English-Canadian Attitudes Toward Aspartame and Aspartame-Sweetened Products: A Qualitative Approach
Authors: Tremblay M-C , Watts TA
Published: March 2009

This exploratory research investigated attitudes of consumers toward aspartame and aspartame-sweetened products in a cross-cultural context. The groups under study were French- and English-Canadians. Focus groups were conducted to gain insight of consumer knowledge and awareness of aspartame and other sweeteners, to discover salient attributes and meanings associated with aspartame-sweetened products, and to explore preferences and reasons behind these stated choices of products. Findings did not reveal major differences in attitudes toward nutritive sweeteners between the two groups. However, knowledge and awareness appeared to be higher for English-Canadians. French-Canadians had a marked preference for desserts and sugar taste. Aspartame-sweetened products were unacceptable in social situations and appeared to have a low status in both groups. Habit was revealed to be an important factor in the relationship between attitudes and consumer behavior, and it seems this variable should be included in models incorporating such concepts. Marketers and product developers need this type of information for research guidance, as it will affect product-related decisions, especially in the early stages of product development.
The Use of Semi-Active Suspensions to Reduce Pavement Damage
Authors: Yi K , Hedrick K
Published: March 2009

Multiple axle groups of heavy trucks can generate peak dynamic tire loads that are greatly in excess of their static loads. This paper reviews previous simulation studies that compare the performance of alternative suspensions (for example, 4 spring, walking beam, and air suspension). In addition, the design of an electronically modulated shock absorber is presented for application on a tandem suspension. Simulation studies are then presented to compare the performance of this concept with the previously discussed suspension types. Recent laboratory data illustrating the performance of semi-active dampers to reduce dynamic tire loads will be presented.
Vehicle Fatigue Induced by Road Surface Roughness
Authors: Poelman MA , Weir RP
Published: March 2009

The purpose of this paper is to present the results of an experiment to determine surface roughness effects, as measured by a response meter, on vehicle suspension. The results suggest that accelerated vehicle suspension fatigue begins to occur on road surfaces with measured road roughnesses less than 2.5 on a Present Serviceability Index (PSI) scale (State of Pennsylvania conversion), and greatly accelerated vehicle suspension fatigue occurs at PSIs less than 1.0.

The basis of vehicle suspension design is to absorb road load inputs to protect the vehicle and driver from variations in the traveled surface. The load input into the suspension depends on the roughness of the surface and the vehicular weight and speed over the surface. Pavement engineers often use PSI to classify pavement wear on the individual roads in their jurisdiction. This paper examines field data from 25 sites ranging in PSI from 0 to 2.5. Using two different instrumented vehicles, load input was measured on each vehicle for eight road load carrying components. The data was analyzed for approximate fatigue response and then compared to the site PSI. The results suggest that for most measured suspension components, fatigue response is affected for PSIs between 2.5 and 1.0 and greatly accelerated for PSIs less than 1.0.

Vehicle manufacturers should be aware of their products' usage in the real world and design their vehicles to be able to accept the appropriate amount of road load input from roads with 2.5 ratings or less. Also, when determining maintenance and resurfacing schedules, road planners should understand at what point the customer may experience significant vehicle damage.
A Review of Tire Traction
Authors: Williams AR
Published: March 2009

This paper reviews the practical knowledge of tire to road friction relative to the tire tread pattern, tread compound and road surface condition. The paper then discusses the influence on tire wet roadhold performance of unevenly worn tires and shows that this condition can lead to performance changes not predictable from the more normally reported evenly worn tire condition. The paper includes results for truck tires in addition to car tires and suggests that continued improvements in the new tire wet roadhold performance will only increase the difference between the new tire and the tire worn to the legal minimum tread depth.