bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination and Verification of Elastic Parameters for Adhesives
Authors: Jangblad D , Gradin P , Stenström T
Published: February 2009

A method is presented for determining the elastic constants E (Young's modulus) and v (Poisson's ratio) for a general adhesive in situ. The method was applied to the structural adhesive FM-300K at room temperature, giving the values E = 2504 MPa and v = 0.34. These constants were then compared with the corresponding constants obtained from an adhesive bulk specimen test, E = 2330 MPa and v = 0.39. The two sets of constants were studied with regard to their sensitivity to scatter in the test results. The study indicates that the in situ method is more stable than the bulk method. Finally, different combinations of elastic constants were used when analyzing scarf joints with different scarf angles using the finite element (FE) method. The scarf joint geometries analyzed were also manufactured and tested, giving large scatter in the elastic stiffness. A comparison of the FE results and the mean values of the test results indicates that the two sets of constants predict the elastic stiffness of the scarf joints with reasonable accuracy.
Development of Alternative Techniques for Measuring the Fracture Toughness of Rubber-to-Metal Bonds in Harsh Environments
Authors: Dillard DA , Liechti KM , Lefebvre DR , Lin C , Thornton JS , Brinson HF
Published: February 2009

Rubber-to-metal bonds are important in a variety of automotive, tire, and marine applications. Rational approaches to design for long term integrity may require accurate determination of the fracture toughness of these bonds during exposure to corrosive environments. Several new techniques are discussed for measuring fracture toughness, and observations are offered for conducting these tests.
A Test Specimen with Constant Stress Intensity Factor
Authors: Groth HL
Published: February 2009

A test specimen was developed that gave a constant value of the stress intensity factor in Mode I under prescribed displacement loading conditions. The test specimen was a double contoured cantilever beam specimen, derived from beam theory. The stiffnesses needed in the analysis and the stiffness as function of crack length were determined by use of the finite element method. For the final shape the valid range of crack extension was established. It is believed that the specimen could be useful for many applications where a constant stress intensity factor is needed, such as viscoelastic crack growth in an adhesive layer.
Determination of Stress Distribution in Double-Lap Joints, Matched Asymptotic Expansions and Conformal Mapping
Authors: Gilibert Y , Rigolot A
Published: February 2009

Double lap adhesively bonded joints were found to present a difficulty in interpreting experimental results in the neighborhood of each extremity of the overlap. The adhesive-air boundary cannot sustain a shear stress, but it is generally impossible to take account of this condition with the order of magnitude of our assumptions on the stress-distribution through the thickness of the specimen. An experimental analysis with electrical strain-gages suggests a new approach based on the matched asymptotic expansions method. Two configurations are chosen, the moderately thin joint and the very thin joint, with respect to the mechanical characteristics of each component of the specimen. In the case of the moderately thin joint, a comparison between theoretical and experimental results is given.
Environmental Effects on Fracture of Adhesively Bonded Joints
Authors: Jurf RA
Published: February 2009

Experiments have been recently completed which characterize the thick adherend bonded joint behavior of two structural adhesives, FM73M and FM300M, subjected to temperature and moisture environments. All the testing was done from room temperature up to the glass transition temperature, and after exposure to three different moisture levels. It was found that the stiffness behavior followed the time-temperature-moisture relationship typical of glassy polymers. The strength of the joint was modeled using fracture mechanics even though there was no initial flaw in the bondline. It was assumed that the crack initiated at one end of the joint and it propagated along the midplane of the bondline. The joint was modeled with finite elements and the critical strain-energy-release rate was calculated using the crack closure technique. For each adhesive, the critical strain-energy-release rate was essentially constant up to the glass transition temperature, and became heavily dependent on the drop in stiffness and reduced failure loads at temperatures beyond the glass transition.
Environmental Durability of Adhesively Bonded Joints
Authors: Pitrone LR , Brown SR
Published: February 2009

Effective determination of adhesively bonded joint durability is crucial for reliable component design and realization of advanced performance. In order to model bond endurance in a manner more consistent with severe service environments, a cyclic stress durability apparatus that achieved constant shear stress without loss due to creep relaxation was designed and implemented for accelerated joint durability analysis of two modified epoxy based structural adhesives. Results were compared with those achieved by sustained stress durability.

Thermal analysis of the bulk adhesives, both before and after hygrothermal exposure, was compared with bonded joint mechanical and durability performance to explore the potential utility of thermal analytical methods in describing adhesive joint properties.

Two cure histories for each adhesive were investigated to establish bonded joint performance and environmental resistance for conventional joint fabrication and potential adhesive/adherend co-curing capabilities.
Three Dimensions Versus Two Dimensions in Fracture Mechanics
Authors: Swedlow JL
Published: February 2009

This study shows that modern-day fracture mechanics has strictly two-dimensional origins. Certain difficulties arise, for example, in meeting fatigue crack-front straightness requirements. Some insight into this problem is available from an analytical study of an elastic thick plate with a central crack, the M(T) specimen. The study found that modest changes in the crack-front shape have a dramatic effect on the distribution of G, the elastic energy release rate. Further examination of the internal stress distribution shows that there is no region in the vicinity of the crack front that can be credibly described as plane stress, whereas an interior region sensibly replicates plane strain. Finally, a call is issued for the development of a three-dimensional fracture mechanics.
Use of R-Curves for Design in the Elastic-Plastic Fracture Mechanics Regime
Authors: Turner CE , Etemad MR
Published: February 2009

Prediction of initiation and maximum pressure was made for two geometrically similar pressure vessels with a fivefold difference in size for two choices of steel. The vessels were supposed to contain a semielliptical axial defect in the outer surface of the cylindrical section and were subjected to internal pressure. Discussion is offered on the choice of data from plane-sided or side-grooved pieces and on the definition and geometric variability of the R-curves. Use of a normalized R-curve to allow transfer of data from a sample to the structure, beyond J-controlled growth, is examined and a comparison is made of all these cases. For these examples, the main effect of the choice of toughness data is on the extent of stable growth prior to maximum load.
Analysis of Crack Arrest Under Elastic-Plastic Conditions
Authors: Hahn GT , Bastias PC , Kumar AM , Rubin CA
Published: February 2009

Elastic-plastic finite-element analyses of quasi-static crack propagation and arrest in a compact test specimen are described. The analyses evaluate the effect of the prior plastic deformation history of the propagation event on the shape of the J-resistance curve of the arrestor. In addition, experiments employing a special device are used to simulate fast fracture and arrest in small laboratory test specimens of ductile HY-80 steel and tough 7075 aluminum. The results show that large dynamic elevations of the J-curve are encountered during arrest. A relatively simple procedure for assessing or designing welded-in, steel crack arrestors, based on these findings is proposed.
Dynamic Moiré Interferometry Studies of Stress Wave and Crack-Tip Diffraction Events in 1018 Steel
Authors: Epstein JS , Deason VA , Reuter WG
Published: February 2009

A study of stress wave propagation around localized crack-tip regions in engineering materials is presented. The principal tool of this initial investigation is dynamic moiré interferometry, which yields full-field continuum boundary conditions of surface displacement in a real-time optical processing manner. The displacement sensitivity employed for this study is 3.3 μm; however, the displacement sensitivity can be as high as 0.2 μm. The spatial resolution developed is less than 1 mm. After a brief review of the technique of dynamic moiré interferometry, the study of a longitudinal pulse, interacting with an artificial crack in a finite steel bar, is presented. Equations for the near-tip elastic dynamic crack displacements will be reexamined to extract localized elastic dynamic stress-intensity factors in light of the capabilities of dynamic moiré interferometry.
A Method for Determining the Crack Arrest Fracture Toughness of Ferritic Materials
Authors: Barker DB , Chona R , Corwin WR , Fourney WL , Irwin GR , Marschall CW , Rosenfield AR , Wessel ET
Published: February 2009

This paper summarizes the results from a round robin test program that was conducted from 1983 through 1985 to evaluate a proposed ASTM standard test method for determining the crack arrest fracture toughness of ferritic materials. The round robin attracted a total of 27 participants from the United States, Canada, Europe, and Japan, each of whom agreed to test three specimens of A514 bridge steel, three specimens of A588 bridge steel, and six specimens of A533 Grade B, Class 1 reactor pressure vessel steel. Twenty-one participants had completed their testing and forwarded test results when this paper was written, which provided a data base consisting of 54 test results for each of the bridge steels at −30°C, 70 test results for the reactor steel at 10°C, and 65 test results for the reactor steel at 25°C. This paper summarizes the test procedure followed in the round robin, discusses the results obtained, and provides the rationale for the modifications to the test method that were recommended in light of the experience gained from this test program. The test procedure has since been revised and is now proposed as the ASTM Test for Determining the Plane-Strain Crack-Arrest Fracture Toughness, KIa, of Ferritic Steels (E 1221).
Biomonitoring as an Integral Part of the NPDES Permitting Process: A Case Study
Authors: Marcus JM , Swearingen GR , Scott GI
Published: February 2009

A case study of integration of extensive biomonitoring into the National Pollutant Discharge Elimination System (NPDES) permit of a synthetic organic chemical manufacturing firm in South Carolina to meet the objectives of the Clean Water Act is presented. NPDES monitoring requirements for specific chemicals and quarterly toxicity tests (Mysidopsis bahia) failed to predict severe water quality degradation in a small estuarine receiving stream. This severe disturbance was documented through benthic macroinvertebrate assessments and sediment elutriate bioassays. Additionally, chemical testing revealed the presence of a myriad of toxic, carcinogenic, and other organic chemicals in sediments and oyster tissue in the receiving stream and in outlying public shellfishing areas.

Implementation of monthly oyster-larvae bioassays, annual benthic macroinvertebrate community structure assessments, annual oyster recruitment/settlement assessments, and continuation of the mysid shrimp bioassays as NPDES permit requirements resulted in a comprehensive tool for actual determination of effluent toxicity as well as for guiding the in-facility reduction of toxicity. This comprehensive approach of laboratory toxicity testing of effluents and field monitoring of benthic macroinvertebrate communities provides a measure for assessing chronic or cumulative effects of complex effluents on aquatic communities, especially when those effluents are highly variable due to batch manufacturing processes. This case study suggests that biomonitoring is now developed to a level where it can be implemented to ensure directly that complex toxic effluents are regulated for optimum environmental protection.
Protocol for the Identification of Toxic Fractions in Industrial Wastewater Effluents
Authors: Gasith A , Jop KM , Dickson KL , Parkerton TF , Kaczmarek SA
Published: February 2009

A toxic fraction identification protocol (TFIP) was developed to identify the fractions(s) of a complex wastewater effluent contributing to toxicity. The TFIP is based on sequential physical/chemical fractionations of the effluent with associated toxicity testing using the aquatic invertebrate test organism Daphnia. Fractionation treatments used in the TFIP include filtration, aeration, activated carbon, and cation and anion exchange treatments. Before and after each treatment, acute toxicity tests are conducted to determine the efficacy of the treatments in removing toxicity. Selected chemical analyses are used along with toxicity test results to identify the toxic fraction(s) in the wastewater. The TFIP can determine whether or not the toxicity is associated with filterable solids, volatile and/or biodegradable organics, carbon adsorbable compounds, cationic or anionic inorganic constituents, and charged organic compounds. The TFIP was developed using six industrial effluents possessing a diversity of chemical constituents. It was validated using a nontoxic industrial effluent spiked with hexavalent chromium and naphthenic acids.
Field Utilization of Clinical Measures for the Assessment of Xenobiotic Stress in Aquatic Organisms
Authors: Versteeg DJ , Graney RL , Giesy JP
Published: February 2009

Histological, biochemical, and physiological measures of xenobiotic effects on aquatic organisms have been utilized extensively in laboratory exposures to document toxic effects. In spite of the ability of these measures of stress to integrate the effects of multiple stressors, and their utility to instantaneously assess the “health” of a population, to date few studies have used these methods in situ to document adverse effects of environmental stressors. This is not due to the lack of information on appropriate clinical methods. Sufficient laboratory research has developed clinical measures to the extent that they will be useful in field situations. A portion of the lack of field use of these methods is a lack of understanding of the utility and knowledge in the flexibility of these diagnostic tools. We have prepared a review of the clinical methods and present a rational scheme for the selection and use of these techniques. Examples of the use of these techniques are presented in the form of two case studies. Each case reviews the literature and recommends specific clinical measures which could be used to quantify the population level effects of the stressors involved in the pollution episode. The case studies involve assessment of the effects on aquatic organisms of pollution episodes involving acid rain and heavy metals.
An Approach for Integration of Toxicological Data
Authors: Shirazi MA , Lowrie LN
Published: February 2009

The practice of reducing a dose-response test into a single number such as LC50 is convenient but inadequate for distinguishing between dissimilar modes of biological response. When the mean curves of two groups of tests with dissimilar slopes at LC50 cross over at a 50% line, they give rise to equal LC50 cross over at a 50% line, they give rise to equal LC50 numbers for both groups of tests, and if used exclusively to represent the results, the single LC50 will mask this difference. The sensitivity of an organism to an incremental change in the dose is measured by the slope of the dose-response curve at any dose level. The slope for some modes of toxic response can be initially zero at small dose, then increase substantially at higher values, and for other modes it can be infinitely large initially, then level off at higher values of the dose. The management of different chemicals requires different strategies that can be supported with a more comprehensive analysis of existing test data.

Several similar or replicate tests produce slightly different dose-response curves due to uncontrollable experimental and biological test factors. Continued focus on summarizing these tests by averaging their LC50 numbers hinders progress toward discovering a biological response mode from the dose-response points of similar tests.

The paper presents an approach for aggregating a group of similar test data into a single mean dose-response curve with error bounds quantifying the variability of the original data. Groups of similar tests are then classified using generalized exponential dose-response functions whose constants define modes of biological response and facilitate calculation of toxicity and sensitivity. Groups of similar data and classes of different groups of tests are used to demonstrate the application and the utility of the approach.
Effects of Pulp Mill and Ore Smelter Effluents on Vertebrae of Fourhorn Sculpin: Laboratory and Field Comparisons
Authors: Mayer FL , Bengtsson B-E , Hamilton ST , Bengtsson A
Published: February 2009

Vertebral quality of fourhorn sculpin (Myoxocephalus quadricornis) exposed to pulp mill or ore smelter effluents was investigated in the laboratory and in contaminated sites near the Swedish coast of the Gulf of Bothnia. Actual effluent samples from pine and birch pulp processes (chlorine bleaching) and a simulated effluent of the ore smelter effluent were tested in the laboratory. In the field, fish were collected from both reference (control) and contaminated sites. Laboratory exposures of pulp mill effluent significantly affected biochemical composition of vertebrae, but no statistically significant effects were observed in fish from the field. Mechanical properties were significantly affected in fish from both the laboratory and field; spinal anomalies ranged from 19 to 38%. Major effects on mechanical properties of vertebrae were observed in the ore smelter study, but the properties affected in laboratory fish differed from those affected in the field. Incidence of spinal anomalies was 47 to 58% in the laboratory and 29% in the field. Effects on fish in the laboratory were related to those observed in the field for pulp mill effluents, but the simulated effluent for the ore smelter elicited vertebral responses different from those in fish exposed to actual effluents in the field.
In Situ, Time-Series Measurements for Long-Term Ground-Water Monitoring
Authors: Benson RC , Turner M , Turner P , Vogelsong W
Published: February 2009

Because recent legislation has made long-term ground-water monitoring an important issue, the methods by which data at a site are collected are of utmost importance. The traditional method of site assessment, which consists of drilling a number of monitor wells from which water samples can be taken and tested, does not provide enough information on which to base a long-term ground-water monitoring program. In situ, time-series measurements using a variety of geophysical techniques, on the other hand, can provide a wealth of information not available through traditional measurement methods.

Over the past ten years, geophysical measurements made from the surface have been used extensively at waste-disposal sites to assess natural hydrogeologic conditions and map the lateral and vertical distribution of contaminants. In recent years, downhole measurements have been used to produce more-detailed information about vertical contaminant distribution through the use of vertical profiles. Examples illustrating these applications are presented in the text. Made at appropriate intervals over a period of time, surface and downhole measurements can be used to provide highly accurate, three-dimensional maps of contaminant flow in ground water and provide a means of early leak detection at waste-disposal sites.

Because the values measured by geophysical methods are dominated by the specific conductance of pore fluids, they can be related to the specific conductance of ground-water samples, thus correlating geophysics with traditional assessment methods. Correlation between in situ, geophysical measurements and inorganic, ground-water sample analyses have been as good as 0.96 at the 95% confidence level. At one landfill, the correlation with total organic carbon was 0.85 at the 95% confidence level.

Three examples of sites where the spatial extents of contaminant plumes have been mapped using geophysical, time-series measurements are presented in this paper. They consist of a localized spill, a large landfill, and a flowing, abandoned well. Measurements taken over a period of time at each of these sites clearly illustrate how the actual dynamics of a contaminant plume can be assessed as it interacts with natural and man-induced variables.
The Modified Reverse-Circulation Air Rotary Drilling Technique for Development of Observation and Monitoring Wells at Ground-Water Contamination Sites
Authors: DB Bennett , Busacca M , EE Clark
Published: February 2009

Ground-water monitoring regulations on the state and Federal level establish general performance standards for the construction of monitoring wells. Of the many drilling techniques available for the construction of monitoring and observation wells, dry techniques are recognized as superior at sites of contamination. The dry technique of modified reverse-circulation air rotary drilling (RARD) is viable and a more advantageous alternative than many traditional techniques. It requires no liquid drilling fluids or muds, and therefore no foreign fluids are added to the aquifer. Furthermore, composite soil and water samples are collected during installation specifically and exclusively from the bit depth and are uncontaminated by drilling fluids. The method utilizes compressed air to clear the borehole and a tube within a tube drill pipe system to maintain the borehole. This allows the well assembly, filter pack, and borehole sealant to be properly placed thereby satisfying the strictest regulatory requirements for short and long-term monitoring. The method accommodates various field testing such as the measurement of in situ hydraulic conductivity and the collection of soil cores. To insure proper construction of monitoring wells, procedures and material requirements must be designed and fully specified.
Verification of Sampling Methods and Selection of Materials for Ground-Water Contamination Studies
Authors: Barcelona MJ , Helfrich JA , Garske EE
Published: February 2009

The development of proven sampling methods which incorporate the use of noncontaminating materials has progressed steadily in the past five years. Once the hydrogeologic conditions and potential contaminant source characteristics have been identified at a particular study site, the selection of drilling methods, suitable sampling mechanisms, and appropriate materials must be made for the chemical constituents of interest. The results of laboratory and field testing of sampling mechanisms, tubing and well casing materials, and sampling procedures have identified elements of sampling protocols which are effective in reducing sampling bias and imprecision. The proper selection of these elements bears on the accuracy and precision of all subsequent measurements, since field blanks, sample splits, replicate samples, and standards can only account for errors which occur after sample collection.

The limited laboratory and field studies of sampling error strongly suggest that poor borehole seals and improper well purging techniques are serious sources of bias for chemical constituent determinations. Sampling mechanisms and materials are also potential sources of bias, particularly for pH and gas-sensitive parameters and volatile organic compounds. Quality assurance must begin with the decisions made in establishing a sampling point (that is, well or dedicated installation) and collecting samples.
Adsorption and Degradation of Enhanced Oil Recovery Chemicals
Authors: Crocker ME , Marchin LM
Published: February 2009

The possible contamination of ground waters by injection of chemicals used for enhanced oil recovery was evaluated at the National Institute for Petroleum and Energy Research. The objective of the study was to delineate the nature of the reservoir rock/injected chemical interactions and the potential for ground-water contamination.

As a preliminary step in the investigation, a method for determining the cation exchange behavior of consolidated sandstone specimens at in situ flow-through conditions as compared to a crushed specimen method at ambient conditions was developed. The flow-through method was tested in the laboratory on small core specimens (0.038 by 0.102 m) and was used as an indicator of the potential of chemicals to interact with the rock matrix.

Results obtained provided individual concentration profiles for major and minor amounts of cations removed from the core after exchanging with lanthanum. The information obtained is valuable in assessing the potential compatibility of injected fluids with a reservoir formation. Upon comparing the cation exchange capacity (CEC) for specimen C071 (Parkman formation, sandstone) the values were 13.9 meq/kg for the crushed method versus 6.11 meq/kg for the flow-through method. This was a consistent finding for all the specimens tested; CECs determined on the crushed core specimens were higher than those determined by the lanthanum flood on the whole core. These displacement tests could also indicate prior chemical contamination by observation of the cations displaced by the flow-through method. This option is not available using the crushed core method.

The whole core flow-through method was adapted to a larger (0.155 by 0.762 m) closed core system to evaluate the stability/degradability of enhanced oil recovery (EOR) chemicals: three surfactants, a co-surfactant, and a polymer. Seven separate tests were conducted with test periods ranging from 17 to 135 days. The tests were conducted at simulated reservoir conditions of temperature, pressure, and fluid flow rate. Specimens were taken periodically and analyzed using gas chromatography, liquid chromatography, ultraviolet spectroscopy, or colorimetric techniques of both. The chemicals were found to be stable for the conditions studied during the testing periods with no detectable amounts of degradation products. These tests indicate the stability of these EOR chemicals over extended time periods at in situ conditions and the potential of the chemicals to contaminate ground-water sources over a long time period.
Monitoring Ground-Water and Soil Contamination by Remote Fiber Spectroscopy
Authors: Klainer SM , Koutsandreas JD , Eccles L
Published: February 2009

Fiber optics, lasers, chemistry, fiber optic chemical sensors (FOCS), optics, and spectroscopy have been integrated to form the new technology of remote fiber spectroscopy (RFS). This method permits the development of ductile probes to detect and monitor ground-water contaminants. The key to this concept is the FOCS, a fiber termination with preselected chemical and physical properties. This is attached to the distal end of the fiber so that specific, sensitive analyses of ground-water constituents can be made. A single fiber is used for both excitation and for collection of the return signal, thus keeping the sensor small and optically simple.

The first FOCS being developed is to be used for both “early warning” and long-term monitoring of organic chloride. The chemical basis for this FOCS is a modified Fujiwara reaction. The FOCS, in conjunction with a field fluorimeter, have been used to make in situ measurements in a chloroform-contaminated well. Preliminary data indicate good agreement between the FOCS data and independent gas chromatography analysis of collected samples.
Application of a New Technique for the Detection and Analysis of Low Concentrations of Contaminants in Soil
Authors: Voorhees KJ , Malley MJ , Hickey JC , Klusman RW , Bath WW
Published: February 2009

A direct method for trapping and detecting volatile organic compounds emanating from contaminated ground water or soil has been successfully demonstrated. The method consists of a static trapping device which is placed just below the soil surface and left for seven to thirty days to insure time for integrated collection of the soil gas. Analysis of the trapped compounds is performed by Curie-point desorption mass spectrometry. Results from two studies conducted in separate Denver industrial complexes showed that the technique is a powerful tool for delineating surface contaminations such as trichloroethylene (TCE), tetrachloroethylene (PCE), toluene, and hydrocarbons. The studies also showed the flux data are useful for inferring the extent and direction of contamination where limited hydrological data are available.
Determining Nonpoint-Source Contamination by Agricultural Chemicals in an Unconfined Aquifer, Dade County, Florida: Procedures and Preliminary Results
Authors: Waller BG , Howie B
Published: February 2009

South Dade County, Florida, is one of the few areas in the continental United States where winter fruits and vegetables are grown. About 85% of the agricultural area is underlain by Rockdale soil composed of crushed limestone and organic debris. The remainder of the agricultural area is underlain by Perrine marl. Both soils must be irrigated and require frequent applications of fertilizer, micronutrients, and pesticides. The agricultural area overlies permeable limestone of the unconfined Biscayne aquifer, which is designated as the sole source of drinking water for southeast Florida. The unsaturated zone in the agricultural area ranges in thickness from 0.3 to 4.6 m.

An evaluation of nonpoint-source contamination from agricultural chemicals began in March 1985. Representative fields from the 30 000 ha under cultivation were selected for ground-water quality monitoring. Agricultural production is comprised of row crops, seasonal tropical vegetables, groves, and commercial wholesale nurseries. Five test plots underlain by both Rockdale and Perrine marl soils were selected for intense evaluation. Wells ranging in depth from 2.4 to 15.7 m were installed in areas hydraulically upgradient and downgradient and near the center of these plots. Additional wells were installed in the shallow mixing zone within and adjacent to the agricultural area to determine background and baseline water-quality conditions.

The ground-water monitoring program was designed to leave in place a permanent well network and sampling stratagem that can be adapted to future water-quality concerns. Wells are drilled by clean water rotary and left open hole in the sampling interval so that organic, inorganic, or biological samples could be taken without contamination by drilling fluids, grouting material, or well casing and screens. A quality assurance program involving 10 to 20% of all samples was used to check field and laboratory procedures and to establish the accuracy of analytical data.

Preliminary results of water-quality sampling indicate that agriculture has had a minimal effect on ground-water quality. Of the constituents sampled, only nitrate and potassium from fertilizers are found at elevated concentrations beneath farmed areas. Elevated concentrations of some nutrients, major ions, and trace metals are found beneath areas used for storage and disposal of agrichemicals.
Fracture Mechanics: Eighteenth Symposium
Authors: Reed RP
Published: February 2009

Description

Over 60 papers present current thinking and research results behind procedures for characterizing the fracture toughness of materials, predicting safety margins against fracture, and predicting fatigue crack growth. Areas of emphasis include ductile-to-brittle transition, mircomechanisms, crack arrest, and sub critical crack growth.
Geotechnical Applications of Remote Sensing and Remote Data Transmission
Authors: Johnson AI , Pettersson CB
Published: February 2009

Description

This book informs geotechnical engineers and related profession about the applications of new techniques in engineering investigation and monitoring programs: satellite imagery and data transmission by satellite or meteor trails. Papers include case studies of successful application of these techniques.
Fracture Mechanics: Nineteenth Symposium
Authors: Cruse TA
Published: February 2009

Description

Identifies the major issues facing the subdivision of fracture mechanics: three dimensional issues; computational and analytical issues; damage tolerance and fatigue; elastoplastic fracture; dynamic inelastic fracture; and crack arrest theory and applications.
The Use of Synthetic Environments for Corrosion Testing
Authors: Francis PE , Lee TS
Published: February 2009

Description

STP 970 will help the user to better assess the credibility and relevance of laboratory corrosion test data as it relates to ultimate materials performance in the final engineering application. This book summarizes experiences in the conduct of corrosion tests using synthesized environments designed to evaluate materials for use in "real" production of natural environments.
Aquatic Toxicology and Hazard Assessment: 10th Volume
Authors: Adams WJ , Chapman GA , Landis WG
Published: February 2009

Description

The 10th volume in this series begins with a review of aquatic toxicology from its early dealing with acute problems, to its current statue as a mature field of science capable of dealing with long-term and sophisticated issues. The volume also features papers in two sections that address new aspects of aquatic toxicology: 1) bioengineering and aquatic environments and 2) application of paleoecological methodology.
Vertebrate Pest Control and Management Materials: 5th Volume
Authors: Shumake SA , Bullard RW
Published: February 2009

Description

STP 974 is the latest offering in the continuing series on the subject of test methods development for materials used in controlling of managing vertebrate pests. Information on birds, rodents and predators/deer is presented in 18 papers. A majority of the papers in this volume are directed toward efficacy evaluation based on new or existing field test methods.
Galvanic Corrosion
Authors: Hack HP
Published: February 2009

Description

Tutorial manual on galvanic corrosion; includes articles from industry, introductory and theoretical articles. Twenty-three papers divided into five sections: theory; computer prediction; testing and control; environments; and industries.
MiCon 86: Optimization of Processing, Properties, and Service Performance Through Microstructural Control
Authors: Bramfitt BL , Benn RC , Brinkman CR , Vander Voort GF
Published: February 2009

Description

STP 979 presents 11 papers that focus on advanced and high temperature materials for the 1990’s and beyond. The papers are divided into three sections: high-temperature materials for power generation, including ferritic and austenitic steels; advanced high-temperature materials for the gas turbine engine and advanced processing, including particle metallurgy and directional solidification; and advanced materials for ground transportation, including one paper on composites.
Effect of Steel Manufacturing Processes on the Quality of Bearing Steels
Authors: Hoo JJC
Published: February 2009

Description

Twenty-two papers address: quality requirements for better bearing steels; new methods to evaluate quality of better bearing steels; and new processes to produce better bearing steels.
Masonry: Materials, Design, Construction, and Maintenance
Authors: Harris HA
Published: February 2009

Description

Fifteen papers present new procedures, concepts, and data in the four major areas of masonry technology: Design; Construction; Materials; and Maintenance.
New Stone Technology, Design, and Construction for Exterior Wall Systems
Authors: Donaldson B
Published: February 2009

Description

International authorities present previously unpublished material on development of exterior wall systems, emphasizing prefabrication and panelization techniques, long-term performance, and testing and analysis. Covers the causes of wall failures and methods for reducing this possibility. For architects, structural engineers, and stone wall fabricators.
Comparable reduction of the visceral adipose tissue depot after a diet-induced weight loss with or without aerobic exercise in obese subjects: a 12-week randomized intervention study
Authors: Christiansen Tore , Paulsen Søren K , Bruun Jens M , Overgaard Kristian , Ringgaard Steffen , Pedersen Steen B , Positano Vincenzo , Richelsen Bjørn
Published: February 2009

Objective

Weight loss with preferential effect on the visceral adipose tissue (VAT) depot could have important clinical benefits. In this study, we investigated the independent and combined effect of regular exercise and diet induced weight loss on body fat distribution.

Design

Randomized control design of i) exercise-only (EXO; 12 weeks of exercise without diet-restriction), ii) hypocaloric-diet (DIO; 8 weeks of very low energy diet (VLED 600 kcal/day) followed by 4-weeks weight maintenance diet) and iii) hypocaloric-diet and exercise (DEX; 8 weeks VLED 800 kcal/day+a 4-week weight maintenance diet combined with exercise throughout the 12 weeks).

Subjects

Seventy-nine obese males and females were included.

Measurements

Body fat distribution was quantified by magnetic resonance imaging (MRI)-technology.

Results

In the EXO group, the weight loss (3.5 kg) and the relative reduction in VAT (18%) was significantly lower compared with the weight losses in the DIO and DEX groups (12.3 kg;P<0.01) and to the reduction in VAT (30–37%;P<0.01). In all the three groups, the relative reduction of VAT was higher as compared with the reduction in fat mass (FM; combining all fat depots determined by MRI;P<0.01 for all comparisons). The changes in VAT were associated with changes in FM and related to the initial VAT/FM ratio (r2=0.72;P<0.01).

Conclusion

Exercise has no additional effects in reduction of the VAT depot, compared with the major effects of hypocaloric diet alone. In addition, the effects of exerciseper seon VAT are relatively limited. The effects on the VAT depot are closely associated with changes in total FM.
Preoperative revascularization in high-risk patients undergoing vascular surgery
Authors: Rácz Kristóf , Tiszai-Szűcs Tamás , Gál János , Kertai D. Miklós
Published: February 2009

Az érsebészeti betegeket fokozott kardiális kockázat terheli a körükben gyakori koszorúér-megbetegedés miatt. A preoperatív kivizsgálás a nagy kockázatú betegek kiszűrését és a tervezett koszorúérfestést teszi lehetővé. Így szükség esetén a revascularisatio az angiográfiával egy ülésben végezhető a perioperatív és a hosszú távú kardiális kimenetel javítása céljából. Ugyanakkor a revascularisatio különböző módszereinek indikációja és hatékonysága a kardiális kockázat csökkentésében ellentmondásos a gyógyszeres kezeléssel összehasonlítva. Áttekintésünk célja, hogy a szakirodalom újabb vizsgálatai alapján megvizsgáljuk a preoperatív revascularisatio különböző módszereinek hatékonyságát, összevetve a konzervatív gyógyszeres kezeléssel, az elektív érsebészeti műtétre kerülő betegek körében.
Gastroenteritis from the aspect of infectologists
Authors: Nemes Zsuzsanna
Published: February 2009

Hasmenést a gastrointestinalis rendszert érintő különböző patológiai folyamatok idézhetnek elő. Az infekt gastroenteritisek világszerte a morbiditás, illetve a mortalitás második leggyakoribb okát képezik. A fejlett országokban a munkából való kiesés, míg a fejlődő országokban a halálozás vezető okai. Évente 5-10 millió ember halálát okozzák. A sokféle etiológiai ágens által előidézett „utazók hasmenése” a fejlődő országokba utazók gyakori, rendszerint néhány napig tartó megbetegedése, az infekció azonban a posztinfekciós irritábilis bél szindróma kiváltásában is szerepet játszhat. Az infekt ágensek vagy az intestinalis mucosához történő adherenciájukkal, vagy a mucosa inváziójával, vagy enterotoxin, illetve enterotoxin/citotoxin képzéssel idézik elő a tüneteket. Akut infekt gastroenteritisekben az inkubációs idő alapján következtethetünk az etiológiára. Ha a lappangási idő 6 órán belüli,
S. aureus
- vagy
B. cereus
-toxin idézi elő a tüneteket. Újabban hipervirulens
C. difficile
-törzsek okoznak járványokat. Néhány patogén ágens krónikus hasmenés okozója lehet, leggyakrabban
C. difficile-, Giardia lamblia-, Entamoeba histolytica-, Cryptosporidium-, Aeromonas- és Yersinia-
fertőzés kapcsán alakul ki. A protozoonok által közvetített megbetegedések közül az amoebiasis a malária után világszerte a második leggyakoribb, halálhoz vezető betegség. A krónikus hasmenés oka lehet a HIV-fertőzés is.
Akt enzyme: new therapeutic target in cancer and diabetes?
Authors: Cseh Áron , Szebeni Beáta , Szalay Balázs , Vásárhelyi Barna
Published: February 2009

A megváltozott sejthalál (apoptózis) számos betegség kialakulásában és progressziójában központi szerepet játszik. Az apoptózist reguláló fehérjék lehetséges terápiás célpontok, ezek egyik tagja az Akt enzim. Az Akt enzim a legtöbb sejtben jelen van. Növekedési faktorok és inzulin, valamint környezeti hatások, így oxigéntenzió-változás és magas hőmérséklet hatására aktiválódik. Az Akt a sejtek metabolizmusában és túlélésében játszik szerepet. Egyes betegségcsoportokban az Akt megváltozott működése figyelhető meg. Számos rosszindulatú daganatban, így prosztata-, emlő-, vastagbél- és hasnyálmirigyrákban, valamint rosszindulatú hematológiai betegségekben az Akt túlműködését igazolták. Diabéteszben egyrészt a béta-sejt-pusztulásban játszik szerepet, másrészt a sejtek inzulinszenzitivitását is befolyásolja. Több kutatási eredmény azt is bebizonyította, hogy a már forgalmazott gyógyszerek egy részének, így a statinoknak, tiazolidindionoknak és az ACE-gátlóknak egyaránt van Akt-moduláló hatása. Jelenleg kutatások folynak olyan Akt-gátlók kifejlesztésére, amelyek a kemoterápia hatékonyságát segíthetik. A perifozin és a triciribin két olyan, fázis I–II. stádiumban lévő Akt-gátló, amely kombinációban adva növelheti emlőrákban, petefészekrákban, gastrointestinalis stromatumorokban, szarkómákban, karcinómákban és hematológiai daganatokban a túlélési idő hosszát.
High Performance InAlAs/InAs/InGaAs Pseudomorphic High Electron Mobility Transistors
Authors: Wakimura Nobuhito , Nakagawa Yugo , Taguchi Hirohisa , Iida Tsutomu , Takanashi Yoshifumi
Published: February 2009

High electron mobility transistors (HEMTs) with a pseudomorphically strained InAs channel (InAs-PHEMTs) were fabricated, and their high frequency characteristics were estimated by measuring the S-parameters. For a VDS of 1.4 V and VGS of 0.3 V, InAs-PHEMTs showed an excellent intrinsic cut-off frequency (fT, int.) as high as 90 GHz regardless of their longer LG (0.7 μm). Since fT is known to be inversely proportional to LG to the first approximation, fT, int. of our InAs-PHEMTs may reach 630 GHz if their LG is reduced to 0.1 μm.

Moreover, we calculated the InAs-PHEMTs' energy state and potential profile by self-consistently solving the Schrödinger and Poisson equations. In solving the Schrödinger equation, the energy-dependent effective mass was employed to take into account the strong non-parabolicity of InAs conduction-band based on the k·p perturbation theory by E. O. Kane. It was clarified that most electrons are confined to the InAs layer. On the contrary, if the non-parabolicity is not taken into account, electrons will spread over the InGaAs channel layer.
Change in Tunneling Spectrum of a Co/AlOx/Co Junction under Constant Voltage Stress
Authors: Horikiri Kouhei , Shiiki Kazuo
Published: February 2009

To investigate the aging effect of a tunneling junction under constant voltage stress, the tunneling resistance and inelastic electron tunneling (IET) spectra were measured. At a low voltage, up to about 0.5 V, the tunneling resistance of junctions increased gradually over time, while above about 0.6V, it decreased gradually. This change was observed independent of voltage polarity. When the applied voltage was positive, the IET spectrum did not change, whereas when it was negative, the IET spectrum changed—the asymmetric peak became symmetric. X-ray photoelectron spectroscopy (XPS) analysis showed that the junction exhibiting an asymmetric peak contained metallic Al at the AlOx/bottom electrode interface, and the junction exhibiting a symmetric peak contained a homogeneous barrier layer. An increase in the tunneling resistance indicates that the amount of metallic Al decreased in the AlO x barrier layer. Transformation from an asymmetric to a symmetric peak indicates that the metallic Al in the AlOx/bottom electrode interface was oxidized, which led to the AlOx layer becoming homogeneous.
Influence of Titanium Nitride Cap Layer Thickness on the Oxygen Sensitivity of Cobalt Films During Silicide Processing
Authors: Hoffman Nathan J , Ketcheson Roger , Stambaugh Daniel , Safran Laura , Campos Richard , Mase Jerry , Codi Daniel
Published: February 2009

Titanium and cobalt silicides have long been used as gate electrode materials for very large-scale integrations (VLSI) circuits. As scaling has pushed the industry to quarter micron technologies and below, cobalt has become the material of choice for forming silicides, since it can maintain its low resistivity on much narrower line widths. Oxidation of the cobalt film is a concern during silicide processing, as the cobalt oxide will not be removed during the cobalt etch step. To protect against the oxidation of the cobalt layer during the silicidation process, the reaction is conducted underneath a titanium nitride (TiN) capping layer. Variations in the TiN capping layer thickness were investigated to determine the affect on oxygen sensitivity of the cobalt silicide process. A strong correlation was found to the thickness of the TiN-capping layer, to the oxygen concentration required to oxidize cobalt during the silicidation process.