bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
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.
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.
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.
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.
Effect of Graphite Fiber/Epoxy Matrix Adhesion on Composite Fracture Behavior
Authors: Drzal LT , Rich MJ 
Published: December 2008

Very little fundamental information is known about the mechanism by which surface treatments and surface finishes influence fiber-matrix adhesion and composite properties. This study is directed at elucidating the molecular mechanisms by which surface treatments affect fiber-matrix adhesion and composite properties.
A polyacrylonitrile based graphite fiber and epoxy matrix were chosen as a model system. Substantial changes were detected in the value of the interfacial shear strength attainable for this fiber-matrix system when only the interphase region was altered. Observation of the interphase under load and high resolution transmission electron microscope (TEM) of ultramicrotomed sections were able to discriminate between various failure mechanisms operating at the fiber-matrix interphase.
An untreated graphite fiber possesses a weak structural layer that can not support high shear loads. When this fiber is stressed in shear the fiber separates from the matrix. Failure analysis shows that the interfacial fracture path involves some fiber fracture in the outer layers as well as along the interface. Surface treatment removes this defect laden outer layer of the fiber and also adds surface chemical groups which increase the interaction with the matrix by a factor of two. The fracture path becomes purely interfacial with no fiber failure. Both mechanisms, that is, surface chemical interactions and morphological changes in the outer layers of the fiber contribute to the increased interfacial shear strength attainable with the surface treated fiber in the same matrix.
Application of a fiber surface finish increases the interfacial shear strength. The mechanism by which this can occur is through the creation of a brittle interphase around the fiber. The original finish layer devoid of crosslinking agent receives some through diffusion from the surrounding resin mixture. This results in a layer more brittle than the matrix. Stress analysis shows that this brittle layer promotes better shear transfer resulting in an increased interfacial shear strength. However, at the fiber breaks, matrix cracks grow perpendicular instead of parallel to the fiber surface under shear loading because of this brittle layer.
Small composite specimens containing the fibers with various surface treatments and possessing the various failure modes were fractured in order to determine if the interphase effects had an influence on composite properties. Results indicate that the single filament behavior is observable in the composite.
Fracture Toughness of Fiber-Polymer Cement Concrete System
Authors: Horiguchi T 
Published: December 2008

Fracture mechanics parameter and energy absorption capacity of fiber-polymer cement concrete are experimentally evaluated and then KIc, JIc, toughness index, modulus of toughness, impact toughness, and bending toughness are examined by means of an analysis of factorial experiments.
Five factors—namely, steel fiber geometry, volume fraction of fiber, unit polymer content, water-cement ratio, and relative notch depth—are assumed to affect these fracture mechanics parameters and toughness parameters.
Experimental scatter of the test method of these fracture parameters is discussed in order to determine the testing method of toughness property of the fiber-polymer cement concrete composite. The confidence interval and significant factors effect are also calculated. Finally, the usefulness and the limitation of fracture mechanics for the application of the cementitious concrete design are discussed.
Fatigue Behavior of Alumina Fiber Reinforced Aluminum Composites
Authors: Tsangarakis N , Slepetz JM , Nunes J 
Published: December 2008

The fatigue behavior of two different batches of an alumina fiber reinforced aluminum composite (FP/Al) was investigated. Both batches had a nominal 55% fiber volume fraction with fibers uniaxially oriented in the test direction. Tension-tension fatigue tests were conducted on flat, untabbed, contoured specimens in a 90 KN MTS axial fatigue test machine at R = 0.1. The cyclic frequency of the fatigue tests was 30 Hz except for a limited number conducted at various frequencies to determine if fatigue behavior was frequency dependent. Some specimens were strain gaged so that load-strain response could be monitored during fatigue tests. Metallographic and fractographic examination of specimens was conducted to evaluate failure modes and damage mechanisms.
Preliminary static and fatigue tests showed a significant difference in mechanical properties of the two batches of FP/Al investigated. The first batch had an endurance limit of 410 MPa compared to 330 MPa for the second batch. Static strength and modulus were correspondingly higher for the first batch than the second. Microstructural differences were also observed, such as a significantly higher number of debonded fibers in the second batch of FP/Al, that could account for the difference in mechanical properties. There was no decrease in secant modulus with fatigue cycling for either batch of material, contrary to reported behavior for boron/aluminum composites. In spite of observed fabrication defects, the ratio of endurance limit and residual strength to ultimate tensile strength was greater than 60% for both batches tested. Fiber failure was found to dominate the fatigue life of FP/Al, and failure of the composite generally occurred after a sufficient number of fibers fractured at a given cross section.
Effect of Coatings on Interfacial Reaction in Tungsten/Nickel and Tungsten/316L Composites
Authors: Umekawa S , Lee CH , Yamamoto J , Wakashima K 
Published: December 2008

Effects of the fiber coating on interfacial phenomena in tungsten/nickel and tungsten/SUS316L (AISI 316L type stainless steel) composites were studied with special emphasis on the diffusion and the chemical reaction. A combination of tungsten fiber without doping and nickel matrix, in which recrystallization easily takes place at elevated temperature, was tested as a preliminary experiment. The combination is rather an extreme example with the recrystallization and interfacial reaction. Then, a composite with the tungsten fiber and 316L stainless steel matrix which would be more adoptable than pure nickel matrix for practical application was employed.
Oxides, carbides, and nitrides of such elements as aluminum, titanium, chromium, zirconium, and tantalum were examined as coating materials. The materials were selected on the basis of the chemical free energy of formation. The composites were exposed under the different kinds of thermal conditions. Effects of coating on the interfacial phenomena were evaluated by such characteristics of the composites as microstructure and mechanical behavior after the exposure.
Among all the coating materials tested, some of zirconium compounds were most effective in tungsten/nickel composites. Accordingly, zirconium dioxide and zirconium nitride coatings were mostly examined in a tungsten/316L stainless steel system. These coatings worked well as the reaction barrier at elevated temperature.