bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical Testing for Fretting Corrosion of Modular Total Hip Tapers
Authors: Flemming CAC , Brown SA , Payer JH 
Published: March 2009

A recent advancement in the design of the total artificial hip is the introduction of modularity. Within the last year clinical retrievals have shown that significant corrosion can occur at the cone-taper interface in some variations of the modular hip. The hypothesis of this study was that the stability of the cone-taper interface affects the amount of fretting corrosion that occurs. The development of a method that can study the taper corrosion and determine the most stable design is therefore necessary.
Design characteristics that may affect corrosion include the use of dissimilar metals, taper angle, taper diameter, percent coverage, machining tolerance, and head neck extension. The fretting that occurred at the interface was initially studied by measuring potential changes while cyclically loading hips in a universal testing machine. This method of measurement proved ineffective at isolating the fretting at the taper interface so current changes were monitored instead. The current was measured when the saline was below the crevice and when it was just above the crevice, and the two measurements were subtracted from each other to produce the taper fretting current.
When comparing two different designs, one showed a significant taper fretting current while the other's was minimal. In a second study, when comparing two different head neck extensions placed on identical stem designs, a significant taper fretting current was seen with the + 10-mm head as compared to a +0-mm head. It is concluded that this method can be used in the evaluation of designs to optimize stability and reduce the resulting fretting corrosion.
A Numerical Time-Frequency Transform Technique for the Determination of the Complex Modulus of Composite and Polymeric Biomaterials from Transient Time-Based Experiments
Authors: Gilbert JL , Dong DR 
Published: March 2009

A numerical time-frequency transform technique is described that can be used to determine the complex modulus of a material as a function of frequency from stress relaxation experiments. This technique uses analog-to-digital data acquisition techniques to obtain the time domain response over several decades of time. Numerical filtering techniques are then applied to reduce spurious noise. An exponential interpolating function is fit to the relaxation data and this function is then transformed into the frequency domain with the use of piece-wise integration of the Laplace transform. The error associated with the numerical transform technique is found to be very small (on the order of 10−4%) when analyzing ideal behavior.
An experimental apparatus is developed and used in conjunction with this technique and initial tests of poly(methyl methacrylate) (PMMA) and polyethylene (PE), and PMMA/GF composites reveal that relaxation peaks (maximums in the loss modulus) associated with molecular transitions in the polymers can be detected with this method. Modulus-temperature-frequency plots indicate that the methodology is able to detect changes in peaks with increasing or decreasing temperature and that some of these peaks appear to correlate with known molecular transitions.
Tests to Evaluate the Mechanical Properties of the Ureter
Authors: Watanabe H , Nakagawa Y , Uchida M 
Published: March 2009

In 1975, we started a research project for the development of microexplosion lith-otripsy. In this project, we investigated the mechanical properties of the urinary tract organs to clarify factors to prevent complications from the method. Tension and expansion tests were performed on the middle portion of the normal ureter taken from fresh cadavers in 1983.
A tension test was performed on eleven ureters in the longitudinal direction and seven in the transverse direction using a universal tensile tester. Tensile strength and maximum tensile stress in the transverse direction of the ureter were weaker than those in the longitudinal direction. Accordingly, it was presumed that ureteral injury first occurred in the transverse direction. The maximum tensile stress of the ureter was higher than that of the bladder, which was previously reported in another paper.
Expansive tests were performed on ten ureters. At the leakage point, the tensile strength and elongation ratio of the external diameter were approximately equal to the tensile strength and elongation ratio measured by tension test in the transverse direction.
It could be concluded from the results that microexplosion lithotripsy could be applicable even in the ureter under certain conditions.
Mechanical Properties and Modeling of the Stress-Strain Behavior of the Urinary Bladder In Vivo
Authors: Saitoh M , Ohnishi K , Matsuda T , Watanabe H , Yokobori AT , Yokobori T , Oki F 
Published: March 2009

A stretch test in vivo for living materials was newly developed and applied to the dog bladder. The stress-strain curve of the normal living bladder was a downward convex and rose very slowly. The curve showed hysteresis and speed-dependence. These results proved that the mechanical property of the urinary bladder was essentially viscoelastic.
A computer analysis, based on the viscoelastic simulation model proposed by Glantz, was performed to evaluate the mechanical property of the bladder. Both proportional and exponential stiffness elevated in the extirpated bladder. In the denervated bladder, changes of the constants were not significant immediately after cutting the pelvic nerves; however, the proportional stiffness elevated remarkably two weeks after cutting. Compared with these abnormal bladders, the elastic constants of the normal living bladder were very low. The viscoelastic properties of the bladder and its low elastic constants seemed to account for the normal bladder function as a reservoir for urine.
Synthesis, Strengthening, Fatigue and Fracture Behavior of High-Strength, High-Conductivity P/M Processed Cu-Nb Microcomposite
Authors: Nayeb-Hashemi H , Pourrahimi S 
Published: March 2009

Materials with both high conductivity and high strength are desired in the design of magnets and rotating electrical machineries. Copper-niobium (Cu-Nb) filamentary microcomposites are such a group of materials. Powder metallurgy techniques (P/M) followed by various deformation processes were used to synthesize these composites. A restacking technique was developed to achieve the high areal reduction necessary to reduce the Nb powder particles to ultra-fine fibers within the Cu matrix. The effects of the Nb volume fraction and size on the evolution of the material microstructure, monotonic tensile properties, and fatigue and fracture behaviors were studied. A strengthening model that combines Cu matrix work hardening, fiber strength, and dispersion-type hardening was developed and shown to predict the yield strength of composites at various stages of deformation processing with reasonable accuracy.
The tensile failure of composites with fully deformed Nb fibers was a shear-type failure (a 45° plane to the specimen axis). However, for composites without fully deformed fibers, the fracture surface had a cup and cone appearance. Fatigue properties of a composite with 18 vol.% Nb and fibers at their fully deformed stage (fiber thickness of 5 to 10 nm) were studied. The mechanisms of crack initiation and propagation were investigated. The final composite failure was due to tensile overload rather than attainment of critical crack length.
Fatigue of a Particle-Reinforced Cast Aluminum Matrix Composite at Room and Elevated Temperatures
Authors: Ogarevic VV , Stephens RI 
Published: March 2009

Constant amplitude low-cycle fatigue, fatigue crack growth, and variable amplitude fatigue tests were performed on a 20% volume fraction SiC particle-reinforced A356 cast aluminum matrix composite at room temperature at 150°C. Data obtained were analyzed and compared with those of the unreinforced matrix material. Variable amplitude loading fatigue life calculations were performed using commercially available software.
The low-cycle fatigue results revealed that the composite material had somewhat lower fatigue resistance than the unreinforced material at room temperature and that the composite fatigue resistance decreased with increasing temperature. Room temperature fatigue crack growth rates were higher, and ΔKth values were lower in the composite compared to those of the unreinforced material. There was not much difference between the composite fatigue crack growth rates at the two temperatures. Positive R ratio increased fatigue crack growth rates of the composite, but had more effect at room temperature than at 150°C. SEM fractography revealed that pores were preferred fatigue crack initiation sites. For small ΔK, fatigue cracks grew predominantly through the matrix, while with increasing ΔK more and more particles were fractured. Micromechanisms of crack growth were of the ductile type in the matrix, while particles were cleaved. Particle/ matrix interface debonding was not observed. Both reasonable and unreasonable fatigue life predictions were obtained with this metal matrix composite using the common low-cycle fatigue and fatigue crack growth approaches.
Dyanamic Analysis of FWD Loading and Pavement Responce Using a Three Dimensional Dynamic Finite Element Program
Authors: Zaghloul SM , White TD , Drnevich VP , Coree B 
Published: March 2009

Multi-layer analyses are commonly used to analyze falling weight deflactometer (FWD) measurements and back calculate pavement layer moduli. This type of analysis assumes static loading conditions and linear elastic material properties. The FWD loading cycle cannot be considered in any sense as a static load. It is a dynamic load with a duration in the range of 30 to 40 msec. Also, paving materials and subgrades are not linear elastic materials and their response to static loads is different than that to dynamic loads, such as FWD loading. The difference between the multi-layer analysis assumptions and actual loading and material conditions is significant.
In this paper a three-dimensional dynamic finite element program (3D-DFEM), ABAQUS, is used to conduct a non-linear dynamic analysis of FWD tests on a flexible pavement section. Verification studies have, been conducted of the 3D-DFEM to verify its static and dynamic analysis of both rigid and flexible pavements and no significant difference was found between the predicted pavement response using the 3D-DFEM and the field measured pavement response. A design of experiment was developed to study the effect of layer thicknesses and moduli on pavement surface deflections at various offset distances. Analysis of variance (ANOVA) and regression analysis were conducted to develop statistical models which can be used to predict pavement surface deflection at different offset distances as a function of layer thicknesses and moduli.
Comparing Laboratory and Backcalculated Layer Moduli on Instrumented Pavement Sections
Authors: Akram T , Scullion T , Smith RE 
Published: March 2009

This paper discusses the analysis of deflection data on thick and thin asphaltic concrete pavement sections instrumented with Multidepth Deflectometers (HDD's). Surface and depth deflection data were collected under both Falling Weight Deflectometer (FWD) and truck loadings. Linear elastic analyses were performed to compare layer moduli backcalculation from; • FWD surface deflections only; and • FWD surface and depth deflections only.
Backcalculated moduli values were compared with those measured in the laboratory. The moduli calculated from FWD loads were also used to predict pavement response under known truck loads. These predictions were compared to actual measured responses. In general it was found that the FWD characterization overestimates the strength of the subgrades and underpredicts subgrade strains induced by the truck by 18%.
Field Testing and Structural Evaluation of Selected Concrete Pavement Sections in Florida
Authors: Wu C-L , Tia M 
Published: March 2009

Twenty-four existing concrete pavement sections covering a wide range of performance levels, ages and types of subbase, surface layers and joints were selected for evaluation in order to determine the causes of the problems in the pavements with poor performance. Each section was evaluated by a condition survey, falling weight deflectometer (FWD) tests, laboratory tests on core samples, and a structural analysis. FWD tests were preformed at both midday and midnight. Loads were applied at four different positions on the slab, namely, slab center, slab corner, edge center and joint center. The measured FWD deflections at various locations were then used along with the results of the laboratory tests on the Cored samples and a finite element program, FEACONS IV, to estimate the pavement parameters. With the pavement modeled by the estimated pavement parameters, the maximum stresses caused by critical temperature-loading conditions were computed using the FEACONS IV program. The computed maximum stresses were then compared with the flexural strength of the concrete to evaluate the structural adequacy of each test section.
The critical stress analysis method, which was used in this study, was shown to give good prediction of the structural performance of the test sections. The use of a very stiff subbase is not beneficial to the performance of a concrete pavement, as indicated by the results of the critical stress analyses as well as field surveys. High elastic modulus of the concrete and long slab length were also shown to produce adverse effects to concrete pavement performance.
Evaluation of NDT Equipment for Measuring Voids Under Concrete Pavements
Authors: Uddin W , Hudson WR 
Published: March 2009

The partial loss of subgrade support associated with voids under portland cement concrete (PCC) pavements leads to increased deflections and increased load stresses. This can cause a significant reduction in the fatigue life of the pavement. This paper presents the findings of a comprehensive research study to establish the performance capabilities and limitations of the following methods and equipment for detection and measurement of voids beneath PCC pavements: (a) Proof Roller, (b) Deflection Equipment, (c) Ground Penetrating Radar Equipment, and (d) Transient Dynamic Response (TDR) Equipment. The records of grout quantity, based on field tests conducted by the highway agencies of several states during undersealing projects, were the prime source to verify the presence of voids.
All methods required extensive manual data analysis and output interpretation. Deflection methods are the least satisfactory because pavement deflections are significantly influenced by daily and seasonal variation of temperature. The TDR method is very labor intensive and relies on subjective interpretation. Radar methods hold good promise if the data interpretation and processing is enhanced.
Viability of High Irradiance Xenon Arc Weathering Tests
Authors: Scott KP 
Published: March 2009

In the field of materials durability testing, the demand for fast answers is ever increasing. All too often though, the validity of a test is sacrificed for the sake of speed.
To obtain acceptable correlation of accelerated weathering tests with end use experience, the exposure procedure should recreate the failure mechanisms caused by natural exposure. Distortions of the critical aspects of weathering must be minimized. The most important of these is the light source.
For the purpose of acceleration there are test methods that specify light sources which are more severe qualitatively than the light present in their end use environment. Such tests often produce anomalous results.
The philosophy of high irradiance xenon arc testing is that, for best results, it is necessary first to closely match the quality of the end use light, then for acceleration, the irradiance (quantity) may be significantly increased.
A case study will be presented which compares a popular test method with a version of itself, where the quality and quantity of the xenon light were modified. The modified test method yielded better results in shorter test times.
New Accelerated Light Fastness Test with Super High Irradiance Using a Xenon Arc Lamp
Authors: Suga S , Suga S 
Published: March 2009

The properly filtered xenon lamp is so similar to sunlight in spectral power distribution among various light sources, especially in UV and visible range, that its use is increasing in light exposure test. However, there is a criticism of this test mainly in automobile industry because of its lack of acceleration.
The authors developed a light fastness test system in which a xenon lamp is used, the distance between the lamp and samples is shortened to get a larger radiation effect, and a filter glass is placed in front of a specimen so as to simulate the actual environment which materials encounter in an automobile compartment. The point was how to simulate a no-air-flow condition and a temperature distribution among the surface and the backing of a material.
In this new xenon lamp testing method, a good correlation with an outdoor exposure test as well as higher acceleration has been obtained. This fading in actual outdoor exposure for one year was reproduced in about five days in the experiments where automobile interior materials, textile and plastics, were used.
Performance of the Toxicity Characteristic Leaching Procedure
Authors: Newcomer LR , Blackburn WB , Hansen GA 
Published: March 2009

The U.S. EPA has recently promulgated the use of a leaching procedure (TCLP) to be used as a criterion for disposal of hazardous wastes under the Land Disposal Restrictions Rule. The TCLP has also been included in the proposed rule for Identification and Listing of Hazardous Wastes.
Summarized are results of eight different studies designed to evaluate the TCLP method. Study results indicate that the TCLP procedure can be applied consistently by a diverse group of laboratories.
Preparation of Radioactive “Mixed” Waste Samples for Measurement of RCRA Organic Compounds
Authors: Tomkins BA , Caton JE 
Published: March 2009

Radioactive “mixed” waste contains radionuclides and varying quantities of semivolatile and/or volatile organics, some or all of which may be named specifically by the RCRA. They are presently stored above-ground at great cost to the user. Analytical procedures which can identify the presence, or at least confirm the absence, of RCRA organics in radioactive waste are necessary for deciding the proper approaches for disposal.
Our general analytical strategy removes organic species in “mixed” wastes in such a way that transfer of activity is minimized. Analytical equipment and procedures listed in EPA-approved methods are used wherever possible; however, alternative procedures such as solid-phase extraction (for semivolatiles) have been evaluated as reasonable alternatives. Final quantitations are performed on the nonradioactive concentrated extract in conventional organic analytical laboratories using EPA-approved analytical methods.
Portable Test Method for the Detection of Halides in Used Oil
Authors: Minucci DA , Finch SR 
Published: March 2009

EPA regulation 40 CFR 261 establishes that any used or waste oil containing greater than 1000 ppm organic chloride may have to be classified as a hazardous waste. EPA estimates that approximately 500 million gallons of used oil and 2 million tons of hazardous waste oil are burned yearly.
In response to the November 1985 rule prohibiting the burning of used oils containing greater than 1000 ppm total halogens in non-industrial burners, the Clor-D-Tect 1000™ kit was developed. This field portable test kit is based on the detection of the total amount of chlorine in an oil sample.
A complete test requires approximately 7 minutes and is ideal for on-the-spot checks by enforcement agencies as well as used oil generators, sellers, blenders and burners. This paper gives results from field studies and gives recommendations for use of the test method.
Development of an Environmental Monitoring Technique Using Synchronous Excitation (SE) Fluorescence Spectroscopy
Authors: Stainken DM , Frank U 
Published: March 2009

Environmental monitoring of discharge plumes (surface and groundwater) and effluents generally involves extensive analyses which frequently employ GC, GC/MS, ICAP or AA techniques. These techniques usually require extraction procedures followed by analyses for specific analytes. When monitoring complex mixtures, these procedures can become more difficult, prone to error and limited by analytical thresholds to the ppb and ppm range. When environmental discharges occur, the dilution process exacerbates analytical problems by lowering concentrations. An alternative/supportive technique is the use of SE fluorescence spectroscopy. This technique can be used for fingerprinting effluents and contaminant mixtures in the ppt range.
An SE fluorescence technique was developed specifically for monitoring effluent from a facility manufacturing a variety of dyes and ancillary products. Prior to discharge, the effluent was treated in a biological and charcoal (PAC) waste treatment system. The effects of sampling (composite, grab), sample storage, fluorescence properties of the effluent (spectral fingerprint) and fluorescence characteristics of the effluent in ambient waters was determined. Consequently, a method was established which “fingerprints” effluent at dilutions of 1:1000, can identify effluent at dilutions of 1:4000, and has fingerprinted similar source material in a rivershed adjacent to the site. This rapid technique can be used to fingerprint and monitor a variety of environmental discharges or plumes when appropriate contaminants are present.
Microscopic Aspects of Ductile Tearing Resistance in AISI Type 303 Stainless Steel
Authors: Saxena A , Daly DC , Ernst HA , Banerji K 
Published: March 2009

The initiation toughness (JIc) and the resistance to stable crack growth (JR-curve) of AISI Type 303 stainless steel were characterized using side-grooved compact-type specimens. The test material was produced by a hot extrusion process which resulted in long cylindrical MnS inclusions aligned in the longitudinal direction. In addition, several interrupted tests were conducted in which CT specimens were loaded monotonically to different levels of stable crack growth. These specimens were sectioned at mid-thickness for detailed metallography to observe the microscopic aspects of the ductile crack growth process and the evolution of damage ahead of the crack tip. Following is a summary of the results and the conclusions from the study.
Stable crack growth or ductile tearing occurs by nucleation, growth, and coalescence of voids which nucleate at the inclusions. Void growth appears to be most dominant during stable crack growth. At JIc the void closest to the initial crack tip coalesces with the crack. During this period, growth of voids further away from the crack tip also occurs. Thus the increment in J required to continue the crack growth process decreases progressively until a steady-state dJR/da is obtained.
Based on the observations of this study and the void growth model of Rice and Tracey, a simple model relating the microstructural parameters such as inclusion spacing and size to the stable crack growth resistance of the material is proposed. The model is capable of predicting the JR-curve. The predicted JR-curve for the test material agreed with the observed behavior.