bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Nonuniform Distributions of Temperature and Thermal Stress in DTA Testing
Authors: Zhu YT , Devletian JH , Chen SJ , Manthiram A 
Published: February 2009

Abstract
A nonuniform distribution of temperature across the solid specimen during differential thermal analysis (DTA) can cause thermal stress. The effect of such thermal stress and the resulting thermal strain energy on the DTA results is theoretically analyzed. It is found that, for most solid metallic specimens, the temperature nonuniformity in the solid specimen is less than 0.18 °C during normal DTA operation. The thermal stress and thermal strain are usually very small due to the small size of the specimen, and they do not have a substantial effect on the DTA results.
A Consideration of Evaluation of Fatigue Crack Propagation Rate from Effective Stress Intensity Factor Range
Authors: Makabe C , Kaneshiro H , Nishida S , Sakihama H 
Published: February 2009

Abstract
The fatigue crack propagation law was investigated for the two cases of crack propagation in a region of welding residual stress and after overloading. In the former case, the crack propagation rate da/dN was found to depend on the stress ratio R defined by σmin/σmax where σmin, σmax are the minimum and maximum cyclic stresses. Due to the tensile residual stress, the crack propagation rate increased as the stress ratio decreased in the range −2 ≤ R ≤ 0. In the latter case, the crack propagation rate da/dN after overloading was higher than that for the constant stress amplitude test at first and then became lower. The crack propagation rate was thus affected by both the residual stress and the overloading. However, the crack propagation behavior correlated well with the crack closure behavior. Therefore, in the cases considered here, the crack propagation law can be reasonably evaluated from the effective stress intensity factor range ΔKeff.
Calibration of DC Potential Technique Using an Optical Image Processing System in LCF Testing
Authors: Merah N , Bui-Quoc T , Bernard M 
Published: February 2009

AbstractThe direct current electrical potential drop (DCPD) technique is applied to monitor fatigue crack growth in plate specimens with central circular holes at room and high temperatures. The application of the calibration curves obtained from replica specimens to both room and high-temperature fatigue testing conditions is studied. The actual fatigue crack length is measured using a video-camera with image processing to assess the reliability of the DCPD technique. The use of two pairs of DCPD probes across the hole and the introduction of a special reference voltage have eliminated the dependence of the potential drop on the hole size and shape as well as the material resistivity and the notch plastic zone size prior to crack initiation. At high temperature, however, the calibration curve should be corrected to take into account the shifting in the potential ratio due to the increases in crack tip plastic zone and crack opening displacement. The effect of the temperature difference between the different potential probes is also examined.By analyzing the results given by the DCPD in connection with the image processing technique, a criterion is suggested to define the interface between the crack initiation and propagation periods.
Evaluation of the Hall Effect Sensor for Pavement Instrumentation
Authors: Sebaaly PE , Tabatabaee N , Kulakowski B 
Published: February 2009

Abstract
This research evaluates a new concept to measure the tensile strains at the bottom of the asphalt concrete layer in flexible pavements. The concept consists of using the Hall Effect sensor in an H-gage configuration to measure the dynamic strains in flexible pavements. The evaluation program included both laboratory and field experiments to evaluate the fundamental and operational properties of the recommended gage design. The laboratory experiment showed that the Hall Effect gage can withstand the temperature and moisture conditions that are encountered during the construction and operation stages of hot mixed asphalt concrete pavements. It also indicated that the dynamic characteristics of the gage are suitable for measuring pavement strains under moving vehicle loads.
The field experiment evaluated the in-service characteristics of the Hall Effect gage under a large number of combinations of vehicle speed, axle load, and tire pressure. The field data showed that the Hall Effect gage has good survivability and repeatability and it compares favorably with other strain gages that have been used in flexible pavements.
A New Technique for Fracture Characterization of Ceramics at Room and at High Temperature
Authors: Pastor JY , Planas J , Elices M 
Published: February 2009

Abstract
A new technique for performing stable tests in ceramic materials is analyzed in depth. The new feature consists in using an analog output of a laser metrology apparatus that measured the crack mouth opening displacement (CMOD), as the feedback signal to control a servohydraulic testing machine. In this study, we go deeply into the analysis of the experimental parameters that control the performance of this technique. Finally, the temperature dependence is shown for the fracture parameters obtained from stable tests of single-edge-pre-cracked-beam specimens (SEPB) of 3 mol% Y-TZP.
Optimization of Lime Content for Fly Ash
Authors: Sivapullaiah PV , Prashanth JP , Sridharan A 
Published: February 2009

Abstract
Abundant quantities of fly ash have been produced by thermal power plants situated all over the world. Many applications of fly ash depend upon its pozzolanic reactivity. This reactivity depends upon many factors, including lime content. Many fly ashes show marked improvement with the addition of lime. However, for every fly ash, there is an optimum lime content for its maximum reactivity. There is no well-established simple test to determine the optimum lime content. In this paper an attempt is made to use a simple physical and physico chemical test to determine the optimum lime content. The principle behind the use of a pH test, liquid limit test, and free swell index test to determine the optimum lime content has been explained. All the methods predict nearly the same optimum lime content and correlate well with that determined by the strength test.
Analysis of the Peel Test: Prediction of Adherend Plastic Dissipation and Extraction of Fracture Energy in Metal-to-Metal Adhesive Joints
Authors: Moidu AK , Sinclair AN , Spelt JK 
Published: February 2009

Abstract
The peel test has been widely used for the mechanical measurement of the adhesion phenomenon. However the proportion of the energy input dissipated plastically within the adherend is a major concern in analyzing peel test data. This paper presents an analytical approach to predict the adherend plastic dissipation in the peel test for metal-to-metal adhesive joints, thereby allowing the fracture energy to be extracted from the test data using an energy balance approach. Expressions are developed for the deflection of an elastic-plastic beam on an elastic foundation, which is then combined with known solutions for the deformation of an elastic-plastic strip under large displacement. The model takes into account both the adhesive and adherend compliance effects on the plastic dissipation. Numerical predictions of the model are presented to gain insight into the effects of adherend properties and peel angle on plastic dissipation in the peel test. It is demonstrated that experimental results with various adherend properties and peel angles are consistent with the predictions of the model. An important conclusion is that for typical structural adhesives, the effects of plastic dissipation may be kept small by using a relatively low yield strength alloy with a thickness much smaller than the critical thickness at which the plastic dissipation effect is a maximum. The extraction of the fracture energy from the test data is also discussed with regard to the mixed-mode nature of the peel test.
A Reversing Direct Current Potential Drop System for Detecting and Sizing Fatigue Cracks along Weld Toes
Authors: Yee R , Lambert SB 
Published: February 2009

Abstract
Steel welded T-joints with 102 mm thick base plates were fatigue tested in three-point bending. A reversing direct current potential drop (DCPD) system was used to detect the initiation of multiple surface cracks along the transverse weld toes of these joints and to monitor the size and shape of fatigue cracks that developed from these cracks. Potential drop readings were obtained by fixed probes straddling the weld toes and normalized with respect to potential drop readings from a remote reference probe. The normalized potential drop readings from each probe were related to the local crack depth by two-dimensional (2-D) calibrations derived by boundary element analyses and the foil analogue method. The fixed-probe arrangement was able to detect 0.4 mm to 1.0 mm deep surface cracks along the transverse weld toes of the T-joints. The 2-D calibrations were able to predict the crack depth at the deepest points of these cracks to within ±10%.
A Compact Testing System for Dynamic Fracture Studies
Authors: Marur PR , Simha KRY , Nair PS 
Published: February 2009

Abstract
Development of a compact instrumented impacting apparatus for dynamic fracture studies designed on the lines of a swing pendulum machine is described. Salient features of the system and instrumentation calibration procedures are presented. The dynamic characteristics of the system are explained with the aid of a simple inertial model. Results of dynamic fracture experiments conducted on aluminum 6061 alloy and polymethylmethacrylate (PMMA) are discussed.
An Improved Method for Threshold Fatigue Crack Propagation Testing on an Electromagnetic Resonance Type Machine
Authors: Nishijima S , Matsuoka S , Ohtsubo S 
Published: February 2009

Abstract
An improved technique of fatigue crack propagation testing is proposed for the determination of threshold stress intensity range ΔKth using an electromagnetic resonance type testing system. A special device is used to compensate for the change of specimen compliance during the test. It is composed of a set of traverses mutually hinged at one end between which an elastic body and a specimen are mounted in parallel, respectively, at predetermined distances from the hinge, so that the resultant composite compliance of the device is designed to be practically insensitive to the change of specimen compliance. A series of ΔKth measurements was performed at various load ratios for six steels of various strength levels, using small compact type (CT) specimens of 25 mm width and 5 mm thickness, under combined control modes of the applied load and the backface strain of the specimen. The use of the compliance stabilizing device improved markedly the controlling stability of the testing machine and facilitated the determination of ΔKth value under autodecreasing ΔK conditions at high load ratios. The obtained ΔKth values from the experiments were in excellent agreement with those found in the literature.
A New Transducer to Monitor Fatigue Crack Propagation
Authors: Liaw PK , Hartmann H-R , Logsdon WA 
Published: February 2009

Abstract
A sputter deposition technique has been successfully used to fuse atomically a high-temperature DC transducer, in the form of a thin film Krak-Gage®, directly onto a test specimen for developing fatigue crack propagation rate data. The rates of fatigue crack growth measured by this technique are in good agreement with those measured by the compliance method at 288 and 427°C (550 and 800°F). The data acquisition and analysis are automated by interfacing with a computer, which saves costly labor associated with fatigue crack growth tests. This new development, based on thin film sputtering technology, is expected to enable researchers to conduct fatigue and fracture mechanics testing in various adverse high-temperature environments.
JIc Measurement Point Determination for HY130, CMS-9, and Inconel Alloy 718
Authors: Matthews JR , West GD 
Published: February 2009

AbstractDetermination of the elastic-plastic fracture toughness for three medium strength materials of varying ductility has been carried out. The materials in order of decreasing ductility are HY130 steel, CMS-9 steel, and Inconel Alloy 718. A survey of measurement-point techniques for JIc has been incorporated in the study to evaluate the effect of ductility on the determination of the elastic-plastic fracture parameter and subsequent estimation of the elastic fracture toughness KIc.
Short-Range Ordering in Nickel-Chromium Thermocouple Alloys
Authors: Pollock DD 
Published: February 2009

Abstract
A short-range, lattice-ordering mechanism has been used extensively to explain the anomalous thermoelectric properties of such alloys as Chromel® and Nicrosil®. This concept appears to have had its origin in early crystallographic work that postulated this mechanism to explain experimentally observed changes in the relative electrical resistance of nickel-chromium alloys. Later crystallographic work, confirmed by several additional investigators, shows no evidence for the existence of short-range order in nickel-chromium alloys containing less than 25 At % Cr. Other investigators, reviewing the short-term thermoelectric deviations of these alloys, describe this mechanism as “much circumstantial evidence of a hypothesis that the short-term emf changes are due to short-range ordering in the Ni-Cr atomic structure of the Type KP thermoelement.” Since short-range ordering has not been established as being responsible for the thermoelectric properties of nickel-chromium alloys, this mechanism may not arbitrarily be considered as the sole rationale for their behaviors.
Variances in Sampling Streams of Coal
Authors: Rose CD 
Published: February 2009

Abstract
Beginning with the postulate that the serial correlation in an infinite population is invariant with respect to segment mass, expressions are developed for variance as a function of mass and expected variance of the mean using random, stratified random, or systematic sampling of a linear population. The expression for variance as a function of mass is shown to agree well with data from one coal experiment and to be the same as an empirical formula developed from agricultural experiments.
A Constant Amplitude Fatigue Study of an Aluminum Powder Metallurgy Alloy
Authors: Santner JS , Campbell G 
Published: February 2009

Abstract
Three test conditions were chosen to conduct multiple constant amplitude fatigue tests on a powder metallurgy (P/M) aluminum alloy. These test conditions were chosen to produce mean target fatigue lives near 1, 50, and 200 kilocycles. A statistical rule was used to select specimens for fractographic examination. Two product forms, a forging and an extrusion, were tested in both the L and L-T orientation. The forging has approximately an 8% lower yield strength and a 20% higher reduction in area than the extrusion. At the 1-kilocycle target fatigue life, the more ductile forging has a statistically better fatigue performance. Beyond 10 kilocycles, the higher strength extrusion appears to have a longer life, although this was not statistically verified. It is suspected this is because of the increased variance at these longer fatigue lives. Further testing is required to verify this point. Additional testing of the extrusion showed that if the data are fitted to a Weibull model, the P/M extrusion has a vastly different failure rate than reported for ingot metallurgy (I/M) products. A decreasing failure rate for the P/M extrusion was verified with a nonparametric test. The difference in failure rates may be related to the finer grain size and constituent particle size found in P/M aluminum products. Additional study is needed to verify this hypothesis.
Contextual Effects in Category Ratings
Authors: Lawless H 
Published: February 2009

Abstract
In sensory evaluations of consumer products, panels of observers often use ratings on category scales to assess differences in the sensory characteristics of products. However, use of rating scales, especially by naive observers, is prone to several biases that may act to distort such judgments. Observers learn about the range and distribution of sensory values for a given characteristics, and then adjust their judgments of that characteristic so that a full range of the available categories are assigned, and so that the categories are assigned with roughly equal frequency. Unless trained and given a constant frame of reference, observers use category scales as relative, not absolute, scales of judgment, adjusting their internal strandards based upon the recent contexts within which a product was presented.
Deconvolution, Derivation, and Smoothing of Spectra Using Fourier Transforms
Authors: Cameron DG , Moffatt DJ 
Published: February 2009

Abstract
Most spectrometers are now digitized, and many include a fast, programmable minicomputer. This has opened up the possibility of routine use of sophisticated data processing methods using Fourier transforms. This paper first covers the properties of spectral lines and their Fourier transforms. It then develops the method of Fourier deconvolution, shows the similarity of derivation, and concludes with a section on smoothing using transforms.
Multicomponent Infrared Analysis Using P-Matrix Methods
Authors: Brown CW 
Published: February 2009

Abstract
Spectroscopic data for single- and two-component systems showing strong deviations from Beer's law have been fitted with the following functions: Beer's law with first order term only, Beer's law with zero and first order terms, and a nonlinear function. The mathematics for performing the analyses are developed and applied to actual systems. Considerable improvements are noted with the more complex functions. The advantages of using a computer for processing the data include the ability to handle the more complex functions and the matrix manipulations. It is shown that these advantages ease the requirements for selecting analytical wavelengths.
Methods for Determination of NH4+-N, NO3−-N and Organic Forms of Nitrogen in Wastewaters
Authors: Ho CL 
Published: February 2009

Abstract
Methods of steam distillation for the determination of NH4+, NO3−, NO2−, and organic forms of nitrogen in wastewaters are described. Oil and grease derived from petroleum and coal processing must be removed by successive extraction with benzene and cyclohexane before distillation begins. To prevent biological nitrogen transformation and assimilation, preservation of water samples with a suitable preservant, such as chloroform, and subsequent analysis of samples within one week are recommended. In the procedure, NH4+ was steam distilled with a specified amount of magnesium oxide, NH4+ + NO3− + NO2− with magnesium oxide plus Devarda's alloy in 3 to 4 min. Nitrite was effectively destroyed with sulfamic acid, thus, allowing its quantitative measurement by difference before and after sulfamic acid treatment, which is before steam distillation. Organic forms of nitrogen in protein, oil brine, and coals were quantitatively converted as NH4+ by a micro-Kjeldahl method at 360°C on a temperature controlled block (Technicon BD-40) digester for 1 to 5 h after clearing. Ammonium recovered by steam distillation is measured either by titration or by a spectrophotometric method. The latter is favored because of its high sensitivity and because only a small amount of sample is required. The methods are applicable to waters of various types. Interference by organic and inorganic substances in water has rarely been encountered.
Determination of Arsenic in Geologic, Biologic, and Water Samples by Flameless Atomic Absorption Spectrophotometry and Inductively Coupled Plasma Atomic Emisson Spectrometry Following Distillation
Authors: Ho CL , Tweedy S , Mahan C 
Published: February 2009

AbstractA distillation method was used to separate arsenic trichloride from interfering substances in the presence of hydrochloric acid, hydrobromic acid, and hydrazine sulfate. Arsenic in distillate was determined by flameless graphite furnace atomic absorption spectrophotometry (GFAAS) and inductively coupled plasma atomic emission spectrometry (ICP-AES). Liberation of arsenic trichloride by distillation was not inhibited by NO3−, Ni+2, or other substances encountered in geological, biological, and water samples. Free nitric acid must be neutralized with potassium carbonate or removed by evaporation in the presence of sulfuric acid at 160°C (320°F) before arsenic trichloride distillation. Geochemical reference samples, U.S. Environmental Protection Agency (EPA) water standards, geological samples, and water samples were analyzed. Results of distilled arsenic trichloride in all reference samples agreed with the reported values. Without distillation, agreement with reported values was obtained only in water samples containing low matrix substances.
Pilot Study for U.S. Geological Survey Standard Reference Water Samples for Pesticides
Authors: Friedman LC , Fishman MJ , Boyle DK 
Published: February 2009

Abstract
The U.S. Geological Survey has been preparing and maintaining a library of standard reference water samples for inorganic constituents for 19 years. Recently, a pilot study was conducted to see if the reference-sample program could be expanded to include pesticides and other organic materials. Two samples containing organochlorine and organophosphorus insecticides, and chlorophenoxy acid herbicides were distributed to a number of laboratories in the United States. One of the samples also contained polychlorinated biphenyls. Interlaboratory data obtained from these round robin studies are presented with intralaboratory information on long-term stability.
Application of Inductively Coupled Plasma Atomic Fluorescence Spectrometry in the Steel Industry
Authors: Lancione RL , Drew DM 
Published: February 2009

Abstract
ICP atomic fluorescence spectrometry has been used to analyze a variety of materials that include an iron ore and a blast furnace slag, as well as low alloy and stainless steels. The technique provides selectable simultaneous multielement analysis with good detection limits. Spectral interferences and background effects are generally avoided and no computer, monochromator, polychromator, or complex scanning mechanisms are required. An examination of the effect of an iron matrix on detection limits shows a small but measurable degradation for aluminum and chromium. The intensity-concentration relationship exhibits strict linearity over three to four orders of magnitude measured from the lowest determinable concentration. The analytical results for aluminum, cobalt, chromium, copper, manganese, molybdenum, nickel, and silicon are in good agreement with certified values.
Advances in Atomic Absorption Graphite Furnace Analysis
Authors: Barrett P , Barnett W , Fernandez F 
Published: February 2009

Abstract
The literature documents a succession of individual improvements over previous graphite furnace technology. These individual improvements include graphite tubes with better pyrolytic coatings, Zeeman background correction, rapid heating of the graphite tube, the L'vov platform, faster instrumental electronics, and matrix modification. Any one of these developments will improve certain analyses. However, taken together as an integrated system, the total is more than equal to the sum of the parts. The integrated system, known as the stabilized temperature platform furnace technique, provides the analyst with capabilities not available on previous graphite furnace systems. Analyses are conducted differently, methods are developed differently, and the results are more predictable.