bluuebunny/crossref_metadata_2025 huggingface dataset:
Crack Growth Resistance Measurement by Crack Opening Displacement Methods
Authors: McCabe DE , Ernst HA
Published: December 2008

In a previous investigation, tests had been conducted on compact specimens made of A508 Class 2A steel to study specimen geometry effects on JR-Curve behavior. No particular geometry effects were shown in specimens ranging in size from ½T to 10T when conditions for J-controlled growth were satisfied. These same specimens had been instrumented to develop crack opening displacement (COD) toughness values using a plastic hinge model. The COD-type R-Curve behavior was examined herein for specimen geometry effects and crack opening angle (COA) behavior.

Plastic hinge (the position of a center of plastic rotation), COD, and COA were determined using a frame-type fixture that had been originally introduced by Andrew. The smallest specimen included herein was 1T and the largest was 10T. COD inferred from the plastic hinge model was determined at the original crack tip position (δ0) and at the advancing crack tip position (δt).

Experimental COD and COA data and some theoretical evaluation schemes indicated that there is geometry-dependent δt versus Δap type R-Curve behavior. It was therefore concluded that JR and experimentally measured COD are incompatible with respect to geometry independence of R-Curve behavior. It was shown that the plastic hinge ratio is strongly influenced by ligament dimensions and that this hinge ratio ultimately controls the δt and δ0 values of COD once the plastic displacement becomes significant with respect to total displacement.
Post-Yield Crack Opening Displacement of Surface Cracks in Steel Weldments
Authors: Cheng YW , King RB , Read DT , McHenry HI
Published: December 2008

Crack-mouth-opening displacements (CMOD) of surface cracks are measured as functions of stress and strain in tensile panels of API 5LX-70 steel plates and welded pipe segments. The experimental results are compared with analytical predictions. For CMOD versus stress, a previously developed model provides good agreement between experiment and analysis for the base metal and the welds. At stresses above net-section yielding, it is observed in seven of nine base metal tests that all the remote displacement is transferred to the crack tip through slip bands extending from the crack tip to the plate edges at 45 deg angles; the two exceptions are in specimens with small (less than 5% of the cross-sectional area) cracks where yielding occurred in the gross section. A model based on this observation is used to calculate CMOD versus strain for net-section yielding; analysis and experiment agree in the intended range, that is, net-section yielding. In the welded specimens, the yield strength of the weld was higher than that of the base metal. Consequently, the base metal began yielding before the weld, and the CMOD in the weld was lower than predicted by the analytical model. A strain-partitioning model partially accounts for the observed behavior, provided the crack is large enough to permit net-section yielding in the weld.
An Overview of the Calorimetric Purity Measurement
Authors: Brennan WP , DiVito MP , Fyans RL , Gray AP
Published: December 2008

The well-known effect of impurities on the melting behavior of crystalline compounds provides the basis for the determination of the purity of these compounds by differential scanning calorimetry (DSC). In the Perkin-Elmer DSC method for the determination of the purity of crystalline compounds, the van't Hoff equation is used to describe the rate of melting of a compound as a function of sample temperature. The presence of an impurity will broaden the melting peak of the compound and lower the final melting point from To, the melting point of a 100% pure compound, to Tm, the melting point of the impure mixture. If careful sample preparation and slow scanning rates are employed to approach thermodynamic equilibrium, accurate estimation of the true purity of a compound can be determined.

The recommended DSC procedure involves the use of a relatively small sample size consistent with homogeneity, the tightest possible encapsulation to minimize temperature gradients within the sample, and the slowest possible scanning rate to approach equilibrium conditions. Also, it is recommended that the melting curve be analyzed over a range of fraction melted (usually 10 to 50%), where the curve is least sensitive to possible gradients in the instrument-sample system.
Preparation and Evaluation of a Set of Thermal Purity Standards
Authors: Moros SA
Published: December 2008

Determining the attributes of any analytical method or comparing methods is best carried out using an actual sample of known composition. When this is lacking, a standard reference material, that is, an appropriate material of reliably known composition which is generally available, may be substituted.

An ASTM Committee E-37 task force recognized the need for a set of thermal purity standard reference materials, chose the phenacetin-aminobenzoic acid system, and, in a collaborative study, showed the viability of a set of standards over the 100 to 98.5 mol % purity range. As an outgrowth of this, quantities of materials sufficient for distribution by the National Bureau of Standards (NBS) and covering a wider impurity range, were prepared. The mixtures were then assayed by independent analysts employing different methods and at various times. Concordant results proved the composition and showed each mixture to be stable and homogeneous.

The NBS is now in the process of evaluating the set of mixtures for designation as Standard Reference Materials.
Optimization of Accuracy and Precision in the Differential Scanning Calorimetry Dynamic Purity Method
Authors: Hunter JE , Blaine RL
Published: December 2008

The effects were examined of specimen size, heating rate, impurity level and data acquisition rate on the precision and accuracy of the dynamic purity method employing differential scanning calorimetry. A set of experimental conditions exist which optimize precision and accuracy. These include: (1) specimen size of 1.7 mg, (2) heating rate of 0.5°C/min, (3) impurity level less than 2 mol %, and (4) data acquisition rate of 120 data points/°C. Slight variations from these values may be permitted thus confirming guideline previously reported in the literature. The errors caused by deviations from these values are shown to be cumulative. Thus, if any one of these parameters must deviate from its optimum value, the others should maintain those values to obtain accurate results.
Purity Analysis by Dynamic and Isothermal Step Differential Scanning Calorimetry
Authors: Elder JP
Published: December 2008

The determination of the purity of crystalline materials by measurement of melting point depression is a well established calorimetric technique. Purity analysis by both dynamic and isothermal step differential scanning calorimetry is considered. The limitations in applying the dilute solution van't Hoff theory to the results of dynamic heat flow measurements are discussed. The two widely used procedures for linearizing the sample temperature-reciprocal liquid fraction data relationship, (T − 1/F), namely, the trial and error, and the Sondack methods are compared. Analytical procedures for materials which decompose or exhibit phase changes during or subsequent to melting are discussed. The precision and accuracy of the dynamic method is demonstrated using data obtained with a three component model system, namely, a pure phenacetin host doped with known amounts of benzamide and p-aminobenzoic acid. The advantages and disadvantages of the equilibrium melting isothermal step method are presented. Providing due allowance is made for the sample heat capacity contribution to the step-wise fusion enthalpy, the T − 1/F relationship is linear over a wide range of 1/F-values, and impurity levels up to 10 mol % may be determined. Examples using the benzamide doped phenacetin system are presented to demonstrate this contention.
Thermal Analysis of a Binary System with Distribution Coefficient Much Greater Than 1:2, 3 Dimethylnaphthalene/Anthracene
Authors: McGhie AR
Published: December 2008

The phase diagram of the binary system 2, 3 dimethylnaphthalene/anthracene was determined using differential scanning calorimetry (DSC). Samples were prepared by either rapidly quenching melts or growing single crystals in a Bridgman oven. The system exhibited Roozeboom Type IV behavior with a peritectic at 115°C and an alpha-phase distribution coefficient of 2.4. This system exemplifies problems associated with determination of purity by DSC.
Determination of the Purity of Metals by Temperature-Dependent Electrical Properties
Authors: Pollock DD
Published: December 2008

It is well known that the electrical properties of metals are strongly affected by the presence of very small amounts of impurities. The employment of the relatively large changes in their temperature coefficients of electrical resistance and in their thermoelectric properties are well established as measures of purity for scientific purposes. However, their utility and worth as means for the determination and control of the degree of purity of commercial metals are seldom recognized or exploited.

The tests described here are applicable to any metal whose degree of purity is of importance in its technical or commercial applications. Very dilute silver-base alloys are used for illustrative purposes. The results of simple electrical resistance and thermoelectric voltage measurements obtained from these alloys, made at just two convenient and easily reproducible temperatures (0 and 100°C), are given. Special equations, derived from fundamental relationships, for the temperature coefficient of electrical resistance and for the thermoelectric voltage, as functions of small impurity contents are in excellent agreement with those obtained from the experimental data. Both greater utility and direct comparison of the effects of impurities are afforded by the use of equivalent composition, rather than atom percent, in these equations. The large degrees to which both the temperature coefficient of electrical resistance and the thermoelectric properties are affected by impurities are apparent. The sensitivities of these properties are compared and their applications are discussed. The thermoelectric properties demonstrate a greater change induced by the presence of a given, small, total amount of impurity present in the metal (sensitivity) than does the temperature coefficient of resistance. Thus, for many practical applications, the employment of simple thermoelectric voltage measurements can provide an accurate, sensitive, rapid, and inexpensive means for the determination of the purity of metals.
Damage Accumulation Techniques in Damage Tolerance Analysis
Authors: Engle RM
Published: December 2008

Damage tolerance analysis requires the capability to assess the damage, usually measured by incremental crack growth, accumulating in a given piece of structure under flight-by-flight spectrum loading. This requirement implies the need to process this damage accumulation over thousands of flights consisting of millions of load cycles. Many models have been developed to analyze the process of damage accumulation under spectrum loading. All these models have been computerized to permit timely cost-effective damage tolerance analyses to be performed.

This paper examines the techniques used to perform the damage accumulation process within these computerized models. Techniques range from simple closed-form numerical integration to sophisticated equivalent damage techniques based on statistical representation of the flight-by-flight spectrum. Recommendations for applications to various types of spectra are offered.
Crack Growth Retardation and Acceleration Models
Authors: Saff CR
Published: December 2008

In predicting crack growth behavior under arbitrary spectrum loads, one must consider the effects of tensile and compressive overloads to retard and accelerate growth. There are two major categories of crack growth models for prediction of retardation and acceleration behavior: yield zone models and closure models. Capabilities and limitations of these models are discussed with respect to accuracy in predicting various growth behaviors.

Yielding at notches or holes can significantly alter the retardation behavior caused solely by crack-tip plasticity. Careful analysis of notch plasticity is required to predict behavior of flaws growing from notches under spectrum loading.
ASTM Fatigue Life Round-Robin Predictions
Authors: Chang JB
Published: December 2008

A series of round-robin predictions of fatigue crack life have been conducted since 1976 by ASTM Task Group E24.06.01 on Application of Fracture Data to Life Prediction. The primary objective of these round-robin exercises was to investigate (1) if the compact type (CT) specimen constant-amplitude fatigue-crack-growth-rate data could be used to predict the growth behavior and lives of part-through crack (PTC) specimens under constant amplitude loading, and (2) if center-crack-tension (CCT) specimen constant-amplitude fatigue-crack-growth-rate data could be used to predict the growth behavior and lives of CCT specimens subjected to variable amplitude and random spectrum loadings. Five sets of round-robin predictions were conducted on a total of 57 specimens that were made of three materials: 2219-T851 aluminum, 6Al-4V titanium, and 9Ni-4Co-0.2C steel. This paper summarizes the results of these round-robin analytical predictions and their correlations to test data.
Investigating the Commercial Instrument Market
Authors: Simmons HC
Published: December 2008

The characteristics of instruments that are available commercially for the measurement of liquid particle sizes are examined critically in relation to the varied needs of users. Deficiencies in the methods employed are discussed, and examples are given of potential sources of error. Recommendations are made to improve the situation.
Measurement of Drop-Size Distribution by a Light-Scattering Technique
Authors: Rizk NK , Lefebvre AH
Published: December 2008

Although a light-scattering technique, using a single-element photomultiplier tube, has proved to be an accurate tool for determining the Sauter mean diameter (SMD) of a liquid fuel spray, it has been generally considered unsuitable for the measurement of drop-size distribution. Usually, a photomultiplier tube on the receiving side of the optical system is traversed in a direction at right angles to the optical axis, and the scattered light intensity due to the passage of a monochromatic laser beam through the spray is plotted against radical distance to provide a measurement of SMD. In the present study it is shown that this same light intensity profile can be also converted into an energy distribution which is uniquely related to drop-size distribution. Values of SMD obtained with this technique show good agreement with corresponding values as determined by a photographic method. Moreover, the drop-size distribution calculated by the proposed method is found to be almost identical to the distribution exhibited by a standard calibration reticle. Typical examples of SMD and drop-size distribution for sprays produced at various test conditions are presented.
A Review of Ultrahigh Resolution Sizing of Single Droplets by Resonance Light Scattering
Authors: Lettieri TR , Jenkins WD
Published: December 2008

Resonance light scattering as a means for ultrahigh resolution sizing of liquid droplets in the 5 to 50 µm diameter range is reviewed. So far, the technique has been used to make relative size measurements with resolutions of 30 ppm on individual, nonevaporating droplets and 300 ppm on individual, evaporating droplets. The calculated existence of resonances sharper than those observed thus far offers the possibility of size resolutions approaching 0.1 ppm on highly transparent spherical droplets. The paper also reviews the relatively small amount of reported work on resonance light scattering from aerosols and from individual aspheres.
Niobium in Industrial Applications
Authors: Webster RT
Published: December 2008

This paper discusses niobium in industrial applications. Niobium is principally used as an alloying element in specialty steels and superalloys and as a carbide in cutting tools for machinery. Niobium alloys containing tin or titanium have become the primary materials used in superconducting applications.
The Impact of Standards on Semiconductor Quality and Manufacturing Efficiency
Authors: Murray Bullis W
Published: December 2008

Standard specifications and test methods have played critical roles in semiconductor device and integrated circuit manufacture. Voluntary standards have led to “white room” environmental control, silicon wafer availability, and establishment of the merchant processing equipment industry, while military standards have been instrumental in improving IC quality and reliability. Participants in the development of voluntary standards help forge industry consensus on important issues while learning about trends, ideas, and procedures well before they become generally available to the industry. The several organizations now actively developing the standards required by advances in device technology welcome new participants.
An Intrinsic Gettering Process to Improve Minority Carrier Lifetimes in Mos and Bipolar Silicon Epitaxial Technology
Authors: Borland JO , Kuo M , Shibley J , Roberts B , Schindler R , Dalrymple T
Published: December 2008

Improvements in silicon epitaxial layer lifetime for CMOS P on P+ and N on N+ as well as bipolar N on P-epi technologies have been observed through the application of a four-step pre-epitaxial heat treatment to activate the intrinsic gettering mechanism in the substrate wafer prior to CVD epitaxial growth. Denuded zones 15 to 70 microns deep with bulk internal gettering sites were achieved and epilayer surface shallow etch pits were not detected on the gettered epi-wafers. Minority carrier lifetime (τ) on gettered epi-wafers showed an improvement in τ by as much as three orders of magnitude.
A Study of Strain in Ion Implanted Silicon
Authors: Sasaki M , Sakamoto K
Published: December 2008

Lattice strain in phosphorus ion implanted silicon has been investigated by the double crystal x-ray rocking curve measurements. The kinematical model for x-ray diffraction was applied to estimate lattice strain of silicon. It was found that the measured maximum strain is not dose-dependent for implanted dose range of 1 to 5 × 1016/cm2. The non-linearity of the relation between the measured maximum strain and the dose was explained by lattice disorder in the highly dosed samples.

The dependancy of maximum strain on the annealing atmosphere (oxygen partial pressure in a mixture of oxygen and nitrogen) was also investigated and it was found that the maximum strain decreases as the oxygen partial pressure (O2/O2+N2) increases. In the case of nitrogen annealing, a relatively large lattice contraction coefficient β =3 × 10−24 cm3/atom was obtained. In the case of oxygen annealing, the lattice contraction coefficient was 1.9 × 10−24 cm3/atom.
Point-Of-Use Ultrafiltration of Deionized Rinse Water and Effects on Microelectronics Device Quality
Authors: Gaudet PW
Published: December 2008

The need for control of molecular contaminants and colloidal particles of 0.2 micron and smaller has resulted from the microelectronics industry's advances into VLSI geometries. Colloidal contamination in the critical rinsing steps prior to high temperature and radiation processing can have a deleterious effect on the properties of these complex devices. Recently, ultrafiltration membrane systems have been developed for point-of-use purification of D.I. rinse water. Ultrafiltration technology, its application and current use in the semiconductor industry, and the effect this technology is having on process cleanliness and device quality will be discussed.
The Effects of Wafer Thermal History on the 450°C Thermal Donor Formation in Cz- Grown P(100) Silicon
Authors: Borland JO
Published: December 2008

The rate and concentration of thermal donors generated during 450°C anneals were observed to be dependent on wafer thermal history. Oxygen thermal donors formed by the silicon-vacancy and silicon interstitial models were examined and the silicon-interstitial donor formation was observed to be the dominating mechanism for the 450°C oxygen thermal donor. Thermally induced microdefects were also observed. Depending on the wafer thermal history less than 1 × 1014 donors/cm3 to as much as 3.7 × 1014 donors/cm3 were formed during the 450°C anneals.
Interaction Between Point Defects and Oxygen in Silicon
Authors: Monkowski JR , Heck D , Baginski TA , Kenney D , Tressler RE
Published: December 2008

The diffusivity of oxygen in silicon was measured for several different processing ambients. Relatively large differences were found, indicating a significant interaction between point defects and oxygen transport in silicon. When this interaction is considered along with the influence of point defects upon oxygen precipitation, previously reported in the literature, the overall intrinsic gettering situation is seen to be a combination of various point defect—oxygen interactions. Furthermore, under certain circumstances point defects grown-in during wafer manufacture are found to be most important, while under other conditions point defects introduced during wafer processing are dominant. In this presentation, these various interactions are discussed along with their implications for device processing.
Effects of Oxygen on Process-Induced Defects and Gettering in Cz-Silicon
Authors: Swaroop RB
Published: December 2008

Process-induced defects (bulk stacking faults (BSF) and precipitate-defect clusters (PDC)), warp and minority lifetime have been investigated in silicon wafers with oxygen ranging from 10 to 33 ppma (ASTM F 121-79). The results indicate that the density of BSF and PDC decreased as the oxygen content decreased. The warp of as-polished wafers did not correlate with the oxygen concentration. Minority carrier lifetime measurements and DRAM yields achieved on very low oxygen wafers (<20 ppma) indicated that extrinsic gettering may be required to improve leakage current and sustain device yield in these wafers.
A Preferential Etch for Silicon Crystals
Authors: Yang KH
Published: December 2008

An investigation of the CrO3-H2O-HF system shows that preferential etching of crystal defects on (100) silicon surfaces is very sensitive to the concentration ratio of CrO3 and HF. The results of this investigation lead to development of an improved etch. This etch consists of one part of volume of 1.5 molal CrO3 (150 g/l H2O) and one part of 49% HF. This newly developed etch can delineate a wide variety of crystal defects with sharp definition, high resolution and smooth background. It can be applied to silicon surfaces of different orientations, such as (100), (111) as well as (110) surfaces. It has a reasonable etch rate of 1–2um/min. In most cases, the etch time required is about 1–3 min., and no ultrasonic or manual agitation is necessary.
A Study of the Spatial Distribution of the Oxygen Content in Silicon Wafers Using an Infrared Transmission Microscope
Authors: Krishnan K , Kuehl D
Published: December 2008

A new high sensitivity microsampling accessory incorporating an all-reflecting microscope for use with FT-IR instruments is described. Measurements of the interstitial oxygen and substitutional carbon concentrations in silicon from sampling areas as small as 100 μm × 100 μm are described. A reflectance version of the microsampling accessory has been used for mapping the epitaxial film thickness on silicon from areas as small as 50 μm × 50 μm.
Influence of Electrically Active Impurities on IR Measurements of Interstitial Oxygen in Silicon
Authors: Weeks SP
Published: December 2008

The presence of electrically active impurities in crystalline silicon causes changes in its optical properties which interfere with IR absorbance measurements of interstitial oxygen content. In this paper we report the use of a theoretical model to accurately simulate the baseline IR absorbance spectrum of n-type silicon over a range of resistivities. This information is used to accurately compensate measured spectra for the effects of free carrier absorption. In addition, empirical limits are set on the range of resistivities amenable to oxygen measurements.
The Effects of Instrumental Artifacts on the Quantitative Determination of Oxygen in Silicon by Ftir
Authors: Baghdadi A
Published: December 2008

The evolution of silicon processing technologies towards greater reliance on internal gettering by oxygen precipitates has led to the need for greater reproducibility in the measurement of the interstitial oxygen content of silicon slices. This measurement is presently being carried out with the use of either Fourier-transform or dispersive infrared spectrophotometers. This paper concerns the investigation of the effects of changing the apodization function and beam geometry on the quantitative determination of oxygen in silicon by Fourier-transform spectrophotometers. The apodization functions used include the boxcar, cosine, Happ-Genzel, and triangular functions. The beam geometry is varied by placing apertures between the interferometer and the silicon specimen. The effects of beam polarization and detector nonlinearity were also investigated.
The Effects of RF Electromagnetic Radiation on Spreading Resistance Measurements
Authors: Mazur RG
Published: December 2008

The metal-semiconductor contacts used in dopant profiling by the spreading resistance technique are point contact rectifiers. Several interfering effects normally associated with point contact diodes, e.g., conductivity modulation through the injection of high densities of excess carriers, local heating of the sample, high-field mobility variation, etc., are avoided in making spreading resistance measurements by using a voltage of only 5 mV across the probes. However, when a spreading resistance system is operated in an environment containing high levels of radio frequency radiation, AC currents are induced in the probes and the semiconductor sample. And, at least for some types of spreading resistance contacts, these currents are rectified and result in significant additional DC voltages across the metal-semiconductor junctions. The maximum DC level observed to date due to RF pickup is about 10 mV. This paper presents a discussion of some of the effects observed as a result of pickup from one particular (500 MHz) source. Also, several practical ways to determine when RF pickup is present and how to reduce or eliminate it are presented.
Comparison of Depth Profiling 10B in Silicon Using Spreading Resistance Profiling, Secondary Ion Mass Spectrometry, and Neutron Depth Profiling
Authors: Ehrstein JR , Downing RG , Stallard BR , Simons DS , Fleming RF
Published: December 2008

Depth profiling of intentional dopants is an important measurement in the semiconductor industry both for process and device modeling and for process control. A comparison of 10B implants into silicon as measured by Spreading Resistance Profiling (SRP), Secondary Ion Mass Spectrometry (SIMS), and by Neutron Depth Profiling (NDP) is presented. The boron implantations were done at several fluences and energies into bare silicon and through several thicknesses of thermally grown oxides. Sources of error and their relation to observed differences among the techniques will be discussed.
Capacitive Microphone Tuning of Ultrasonic/Thermosonic Bonders
Authors: Loofbourrow WL
Published: December 2008

Scheduling ultrasonic bonders for optimum settings has long been a mystery. As device bond pads get smaller and silicon and gallium arsenide devices get thinner, ultrasonic energy control at the bond interface becomes very critical. The use of a capacitive microphone sound meter to measure the compressional sound waves at the lower tip of a bonding tool has helped to control these critical energy settings. The results of implementing this process on 25 thermosonic bonders has reduced the damage to microwave devices by 30% and decreased the wire bond assembly time 25%.
Bumped Tape Processing and Application
Authors: Lindberg FA
Published: December 2008

The object of this research was to develop an inner-lead bonding technique for making multiple thermocompression bonds between gold-plated copper bumped tape leads and standard aluminum integrated circuit chip bonding pads. An experimental technique was developed to arrive at the optimum bonding parameters for a given set of bonding conditions that include the aluminum bonding pad thickness, copper bump size, copper alloy, and initial copper hardness. A laboratory inner-lead bonding machine was modified to enable it to make dynamic measurements of the chip temperature response and bonding force. Bonding parameters were evaluated with destructive pull tests. The results indicate that each combination of chip design and tape design requires unique bonding machine settings to achieve the proper combination of temperature and compressive stress at the gold/aluminum interface.
Neutron Transmutation Doping of Semi-Insulating Czochralskigrown GaAs
Authors: Hunter AT , Young MH , Winston HV , Marsh OJ , Hart RR
Published: December 2008

We have carried out neutron transmutation doping of undoped, initially semi-insulating, Czochralski-grown GaAs. We employed a series of nine neutron doses, which added between 2×1015 and 5×1017 cm−3 Ge and Se to the samples. Electron concentrations determined from Hall effect measurements on annealed samples with the three highest doses agree with the concentration of added Ge and Se within 5%, although the uncertainty in the measurements is 20%. These data are consistent with photoluminescence data which suggest 10% of the amphoteric Ge acts as an acceptor in the annealed material. Room temperature and temperature dependent Hall data place an upper limit of 4.9×1015 cm−3 on the concentration of donors of intermediate depth, consistent with our model for semi-insulating material.
Biological Sampling Methods and Effects of Exposure to Municipal and Chemical Landfill Leachate on Aquatic Organisms
Authors: Janisz AJ , Butterfield WS
Published: December 2008

Extensive biological sampling on five abandoned hazardous waste sites in New York, New Jersey, and Puerto Rico was undertaken during 1981 and 1982 to determine the impact of priority pollutants on aquatic fauna and, potentially, on human health. The selection criteria for sites, sampling equipment, problems in personnel protection, and sample handling procedures are presented.

The effects of the hazardous waste sites were assessed using a wide range of fish and invertebrate species. Tissue specimens from eleven vertebrate and eight invertebrate species were analyzed. Forty samples of these tissue specimens were analyzed for all inorganic priority pollutant parameters; an additional 35 samples were analyzed for organic priority pollutants or an appropriate subset of them. High concentrations of polychlorinated biphenyls (PCBs) were found in aquatic organisms exposed to chemical landfill leachate; the results of the tissue analyses at other sites were negative.
Analysis of Chemicals for Waste Disposal
Authors: Belkin F , Bishop RW
Published: December 2008

The U.S. Army Environmental Hygiene Agency (USAEHA) is responsible for investigation of problems associated with the management of hazardous wastes for the U.S. Army. One type of disposal problem arises when an unlabeled container of material is located and disposal is desired. The sample is evaluated in the field by obtaining a history of the material to be disposed, the types of operations performed on the installation, and the length of time and conditions of storage. A proper sample is required, sufficient for analysis, but not so large as to create shipping and disposal problems for the laboratory. Qualitative test results, sample history, physical properties, required detection limits, regulations concerning disposal, and sample preparation are considered when choosing an appropriate method of analysis. An analytical scheme using a variety of instrumental techniques has been developed for the analysis of waste disposal samples. Quality control and good laboratory practices are employed in ensuring the accuracy of the complex analysis.
Prediction of Cation Mobility in Soils from the Linear Distribution Coefficient
Authors: Wong K-FV , Sengupta S , Dasgupta D
Published: December 2008

The ability to predict pollutant migration in the soil should be one of the objectives in disposal operations because the soil is the ultimate receptacle of the waste. The objective of the present work is to determine the relative mobility of different cations in a mixture traveling through the soil. The method used here is to derive a relationship from the exact solution to the one-dimensional, convective-dispersive-adsorptive equation which describes the motion of a cation within a complex mixture moving through the soil. It has been found that the length of time a cation in solution mixture takes to travel a certain depth of soil is directly proportional to (1 + K′ where K′ = [K ρ(1 − ε)]/ε, K is the linear distribution coefficient.
Codisposal of Oil Wastes with Domestic Solid Wastes in Landfills: Leaching and Persistence of Oil
Authors: Barber C , Maris PJ , Bull SC , Johnson RG
Published: December 2008

Controlled landfill offers a possible alternative for the disposal of oily wastes, and research has been carried out to assess the impact of these practices using laboratory simulations and a site study.

These studies showed that oil emulsions (cutting oil and mousse) were rapidly broken down to free oil and an associated aqueous phase in the landfill. The oil was readily sorbed by domestic waste solids, whereas the aqueous phase was flushed out with leachate. Concentrations of oil in leachate were, in most cases, similar to those found in leachate from domestic wastes only (within the range of 5 to 10 mg/L). It was probable that under anaerobic conditions in the fill, oil was not significantly degraded by microorganisms, small losses of oil being mainly due to leaching.

It is concluded that water pollution (surface or groundwater) from the disposal of small volumes of oily wastes with domestic wastes will not be significantly greater than pollution by leachates from domestic wastes only. It is possible that, at small landfills, disposal of excessive quantities of aqueous oil emulsion wastes could exceed the sorptive capacity of the domestic wastes and give rise to leaching of oil.

The persistence of oil in a landfill for long periods of time is an additional problem, which has consequences for the long-term development of land “reclaimed” with wastes containing oils.
Siting of a Metals Industry Landfill on Abandoned Soda Ash Waste Beds
Authors: Rinaldo-Lee MB , Hagarman JA , Diefendorf AF
Published: December 2008

A recent application by a steel-manufacturing plant to obtain a permit for an industrial landfill on abandoned soda ash waste beds near the city of Syracuse, New York, resulted in an extensive hydrogeologic and geochemical investigation. This investigation was initiated because of (1) previous disposal of waste by the metal manufacturer at this site and (2) the unique location of the landfill on top of preexisting waste beds on the shores of Onondaga Lake. The waste beds cover approximately 1 473 000 m2 to a depth of 20 m and consist of hydraulically placed hydroxides, salts, and residues, all byproducts of soda ash production. The metals-manufacturing wastes have been placed as a thin (0.5 to 2 m) layer over an area of 69 000 m2 on the soda ash waste beds during the past ten years. The primary leachate contaminant of concern has been hexavalent chromium.

The groundwater monitoring program and investigations included installation of 76 monitoring points including wells, piezometers, lysimeters, and seepage galleries. The hydrogeologic investigation included 30 permeability tests, over 600 water quality samples, and development of a three-dimensional, seven-layer groundwater model of the site. A significant groundwater mound was identified within the waste beds. Groundwater flows predominantly downward through the soda ash wastes into thick underlying alluviolacustrine and glaciolacustrine deposits and ultimately into Onondaga Lake. The results of groundwater monitoring over a one-year period indicate no detectable chromium from the metal-waste leachate escaping through the soda ash wastes. Retention of hexavalent chromium within the underlying highly alkaline soda ash wastes by adsorption, reduction, and precipitation suggests a viable means for in situ treatment of several metals-manufacturing waste products.
Food Processing Wastes as Nutrient Sources in Algal Growth
Authors: Wong M-H , Chan W-C , Chu L-M
Published: December 2008

Utilization of food processing wastes for biological production will ease part of the disposal problem, especially the potential hazards of eutrophication, and at the same time recycle the inherently rich plant nutrients in the waste materials.

The present investigation is an attempt to study the feasibility of using five food processing wastes, including carrot, coconut, eggshell, soybean, and sugarcane, for culturing Chlorella pyrenoidosa (a unicellular green alga).

When using test tubes as culture tubes, all the concentrations (0.5, 1, 3, and 5% weight/volume aqueous extracts) of eggshell waste had similar growth rates, whereas all the concentrations of sugarcane and carrot wastes had higher growth rates of algal cells compared with the control group using Bristol solution as the culture medium. However, only 0.5 and 1% soybean waste and 3 and 5% coconut waste had higher algal growth than the control.

When larger containers were used, similar results were obtained except for 5% soybean waste, which produced the highest growth rate. This was possibly due to the modified growing conditions. Chlorella pyrenoidosa harvested from soybean and sugarcane wastes had higher cell numbers, dry weight, and protein contents than those cultivated in the Bristol solution.

These waste materials contained high levels of essential plant nutrients including nitrogen, phosphorus, and potassium. However, the rather high levels of organic carbon and soluble carbohydrate in some of the wastes, such as coconut and carrot wastes, seemed to affect the contents of protein and chlorophyll of the waste-grown algae.

The fact that these waste materials contained no hazardous substances would render the algal products safe for subsequent usage (as animal feeds or even for human consumption), unlike the sewage-grown algae which accumulated a substantial level of trace metals.

It is suggested that the process of algal culture could be incorporated in large-scale food processing industries for the dual purpose of treating the wastes and mass producing edible protein.
Management of Industrial Solid Wastes in Alexandria, Egypt
Authors: Hamza A , Gallup JD
Published: December 2008

Developing nations must locate their manufacturing operations where available resources and facilities make them most efficient. The presence of more than one third of the Egyptian industries in urban Alexandria has placed an undue burden on natural resources and has aggravated pollution problems.

The U.S. Environmental Protection Agency (EPA) is conducting a study to identify existing and future industries in Alexandria, estimate the solid wastes produced by these industries, examine methods of reusing solid and other wastes, and assess the feasibility of these methods from the technical, economic, and environmental points of view.

This paper presents a summary of the first phase of the EPA project, which encompasses surveys of residues from industrial sources in Alexandria. Studies to date indicate that wastes from various industries can be recovered economically. Wastes such as tin cans, glass, wastepaper, and food residues from processing of fruits, starch, and beer are examples of reusable industrial wastes in Egypt.

The results of experimental studies for reuse of residues from oil refining, starch and yeast processing, and steel pickling are presented. Spent clay from edible oil refining is currently discarded, causing both handling and disposal problems. This clay contains as much as 40% oil; 90% can be recovered by extraction. The recovered oil can be successfully used in soap production, and the spent clay can be reused in oil bleaching. Other examples include starch and yeast wastes, which can be used for animal feed, and spent pickling liquor, which can be used as a coagulant aid for treating paper mill wastewater.

A centralized system for collecting and treating hazardous residues is proposed to permit economical recovery of valuable materials.
European Community Action on the Management of Waste Products
Authors: Klein L
Published: December 2008

The objectives of the European Economic Community (EEC) in actions regarding waste are prevention, recycling, and elimination. The EEC's environmental action programs set out the priorities and aims of the organization, as well as supply the necessary legal backing for the resulting actions and provide insight into the institutional and legal background of the EEC.

The three main spheres of action, which form the basis of the EEC's environmental policy, are (1) prevention of the production of waste products, (2) elimination, without danger, of nonrecoverable residues, and (3) recycling and reuse of wastes. Statistical data are presented to show the scale of the problem in the ten member states.
Three-Dimensional Finite-Element Analysis of Chevron-Notched Fracture Specimens
Authors: Raju IS , Newman JC
Published: December 2008

In this paper, stress-intensity factors and load-line displacements have been calculated for chevron-notched bar and rod-fracture specimens using a three-dimensional finite-element analysis. Both specimens were subject to simulated wedge loading (either uniform applied displacement or uniform applied load). The chevron-notch sides and crack front were assumed to be straight. Crack-length-to-specimen width ratios (a/w) ranged from 0.4 to 0.7. The width-to-thickness ratio (w/B) was 1.45 or 2. The bar specimen had a height-to-width ratio of 0.435 or 0.5. Finite-element models were composed of singularity elements around the crack front and 8-noded isoparametric elements elsewhere. The models had about 11 000 degrees of freedom. Stress-intensity factors were calculated by using a nodal-force method for distribution along the crack front and by using a compliance method for average values. The stress-intensity factors and load-line displacements are presented and compared with experimental solutions from the literature. The stress-intensity factors and load-line displacements were about 2.5 and 5% lower than the reported experimental values, respectively.
A Comparison Study of Fracture Toughness Measurement for Tungsten Carbide-Cobalt Hard Metals
Authors: Hong J , Schwarzkopf P
Published: December 2008

KIc-values of tungsten carbide-cobalt (WC-Co) hard metals were measured using the short-rod (chevron-notched) specimen geometry. Nine alloys of various cobalt contents and tungsten carbide particle sizes were tested using modified self-aligning tensile grips. A compliance method was adopted for the test.

For comparison, the same WC-Co alloys were tested using single-edge-notched beam (SENB) specimen geometry in four-point bending. A sharp notch was introduced into the SENB specimen using a thin copper foil blade in an electrical discharge machine (EDM).

The same alloys were also tested using Barker's flatjack method with short-rod specimen geometry.

Microstructural parameters, mean free path of cobalt, mean intercept length, and contiguity of WC, were measured using a semiautomatic image analyzing method for all the alloys. Optical, scanning electron, and transmission electron micrography were used for quantitative image analysis. From these microstructural parameters, KIc-values were calculated using a theoretical equation derived by Hong and Gurland.

The four independent experimental KIc-values for nine alloys are discussed with respect to the accuracy and convenience of each experimental measuring technique.
Fracture Toughness of Polymer Concrete Materials Using Various Chevron-Notched Configurations
Authors: Krause RF , Fuller ER
Published: December 2008

The fracture toughness of two similar polymer concrete materials was determined using several fracture mechanics configurations to show any influence of crack geometry on resistance to fracture in these materials. The testing configurations included a conventional straight-through notch in a flexure bar and various chevron-notched geometries in both flexure-bar and short-rod specimens. The materials were polymerized mixtures of monomers, anhydrous Type III portland cement, and silica sand. In one composition the monomers were styrene and trimethylolpropane-trimethacrylate; whereas, in the other composition, acrylonitrile was added as well. The fracture toughness was calculated from published stress-intensity coefficients for the straight-through notch which were adapted for use with a chevron notch by assuming that the derivative of the compliance with respect to crack length was the same for both notch types. Effects of varying chevronnotched angle, chevron-vertex position, and width of specimen in the crack plane were examined. Variation of these parameters to produce a wide variation in the width of the crack front shows minor if any influence on the fracture toughness measurements. In contrast, however, the calculated amount of crack extension for all the various specimen configurations indicates a trend of fracture toughness which is consistent with the concept of a rising crack-growth resistance curve for these materials.
Low-Temperature Fatigue Crack Propagation in a β-Titanium Alloy
Authors: Jata KV , Gerberich WW , Beevers CJ
Published: December 2008

Fatigue crack growth rates and crack closure have been examined for a body-centered-cubic (bcc) titanium alloy (Ti-30Mo) at five test temperatures ranging from 123 to 340 K. In the same temperature range the influence of internal hydrogen (as provided by gas phase charging) has been studied. Detailed fractographic analyses have been made to quantify the amount of cleavage fracture as a function of test temperature, hydrogen concentration, and stress intensity factor range. The extent of cleavage, both cyclic and static, increased with decreasing temperature. For the lowhydrogen content specimens the fatigue crack growth resistance increased with increasing cleavage over the temperature range from 340 to 190 K. The fatigue crack growth resistance for the high hydrogen alloy remained relatively insensitive to the increasing amounts of cleavage over the same temperature range. An examination of the fatigue crack growth rate data shows that the power exponent in the following expression is in the range of 2 to 2.5 for temperatures of 123 to 340 K: 1dadn=B(ΔKi−ΔKthi)n where ΔK = ΔKi = ΔKc and ΔKi is the intrinsic component and ΔKc is the closure component. These observations indicate that the factor dominating the fatigue crack growth rate and the resulting cyclic cleavage process is the reverse plasticity in the crack tip region. The increased resistance to fatigue crack growth in the temperature range from 340 to 190 K for the low hydrogen contents is attributed to the higher yield stresses in this region. The role of hydrogen in determining fatigue crack growth rates and fatigue thresholds (ΔKth) is discussed in terms of its influence on both ΔKi and ΔKc.