bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of Permeability at Elevated Stresses and Temperatures
Authors: Voegele MD , Brace WF 
Published: December 2008

Laboratory measurements of the permeability coefficients of various rock types suggest that the permeability coefficient is sensitive to the temperature and the stress state at which it is measured; the effects become more pronounced as the temperature or stress state is increased. This paper presents a summary of data in the literature to support this statement and describes some laboratory techniques used to obtain the data base.
Laboratory observations indicate that the permeability coefficient is temperature sensitive and that it is affected in many different ways as the temperature is increased. Temperature might be expected to affect the permeability coefficient through purely physical effects such as thermal expansion or thermal cracking. However, a variety of fluid-rock interactions apparently play a role, evidently through pore geometry alteration, which can have profound effects on the value of the permeability coefficient. The changes in permeability coefficients caused by temperature reviewed in the paper were large but not quantitatively predictable.
The permeability of rock is known to depend upon pore dimensions and fracture geometry. Either one, or a combination of the two, can control the measured permeability depending on the type of rock and its stress-strain history. Pore dimensions, particularly the aperture and the fracture width, change with stress so that it is not surprising to find that the permeability coefficient of various rock types can be quite stress dependent. The paper discusses general trends in stress related behavior changes for both low and high porosity unjointed rocks as well as for some jointed rocks.
Efficacy of Insecticides Applied Ultra-Low Volume in Vegetable Oils
Authors: Luttrell RG 
Published: December 2008

Increased use of vegetable oils as carriers for insecticide sprays has stimulated additional research related to the efficacy of aerial application of insecticides. The efficacy of insecticides applied as ultra-low-volume (ULV—2.34 L/ha [0.25 gal/acre]) vegetable oil sprays was compared with standard volume (SV—18.71 L/ha [2 gal/acre]) water sprays in field experiments involving a complex of cotton insect pests at several locations in Mississippi during 1981 to 1983. Results suggest that insecticides applied as ULV-vegetable oil and SV-water sprays are equally efficacious against cotton insect pests.
Bioassay data and spray deposit characterizations were used to study more accurately differences in ULV-vegetable oil and SV-water sprays. Spray droplets associated with ULV-vegetable oil sprays tend to be smaller and deposited in a less dense pattern than those of SV-water sprays. Bioassay and residue analyses data indicate that ULV-vegetable oil and SV-water sprays deposit comparable amounts of active ingredient on the target area.
Control of Spruce Budworm by Ultra-Low-Volume Application of an Insecticide Suspension
Authors: Shafer JG 
Published: December 2008

The spruce budworm, a native insect in the Eastern United States and Canada, can cause defoliation severe enough to kill a tree within a year. For a number of years, Matacil has been used to control the insect. The formulation is a true solution containing 180 g of Matacil per litre (1.5 lb/gal). It is mixed with diesel oil and applied ultralow volume (ULV).
It was desired to have a formulation that could be mixed with water as well as oils. This was accomplished by changing the formula from a true solution to a suspension in oil. The suspension can be mixed directly with oil or after addition of an emulsifier, with water.
Biological efficacy data supported the formula change. Spray patterns and droplet size counts showed that ULV application of the suspension by fixed-wing aircraft was feasible.
New Developments in Automated Materials Testing Systems
Authors: Miller NR , Dittmer DF , Socie DF 
Published: December 2008

This paper traces the development of automated materials testing systems over the past ten years. The rapid reduction in computing hardware costs in recent years, coupled with fundamental improvements in computing systems design, has led to the development of a new generation of test control systems. The paper focuses on recent developments in this area at the University of Illinois at Urbana-Champaign.
The paper describes in detail a microcomputer-based controller designed to be used with a standard servohydraulic test frame. The controller uses menu-driven software which permits the operator to set up and execute tests, sample and store data, and transfer the collected data to a host computer system for data reduction and archival storage. Currently, software exists to perform standard low-cycle fatigue tests and other related test procedures. The software is designed to permit ease of operation and reduce the chance of operator error. In addition, numerous checks are performed during the course of a test to assure that the test is carried out in accord with ASTM specifications where applicable.
The paper contains a discussion of digital communications as they relate to the materials testing laboratory. The growing array of computing hardware in the testing laboratory necessitates the careful selection of communication techniques to match the needs of each application and the laboratory as a whole. The paper concludes with a discussion of the impact of new testing techniques on testing standards.
Development of an Automated Fatigue Crack Propagation Test System
Authors: Vecchio RS , Jablonski DA , Lee BH , Hertzberg RW , Newton CN , Roberts R , Chen G , Connelly G 
Published: December 2008

An automated fatigue crack growth rate test system was developed to characterize the crack growth response of engineering materials as a function of the applied stress-intensity range. The test system utilizes DEC PDP 11 series minicomputers and a software feedback control loop to control testing at frequencies up to 100 Hz. Additional system flexibility is provided in its three control modes: constant-load amplitude, constant ΔK, and variable-ΔK test capabilities.
A comparison of crack growth rate data obtained using this automated system is made with data generated under manually controlled test conditions, for aluminum and steel alloys, and for engineering plastics.
An Automatic Fatigue Crack Monitoring System and Its Application to Corrosion Fatigue
Authors: Kondo Y , Endo T 
Published: December 2008

A measuring system that automatically detects fatigue crack initiation and propagation behavior has been developed. This system is based on calculating and recording automatically the change of compliance due to fatigue crack growth using an analog circuit.
The authors applied this system to fatigue testing in an aqueous environment and succeeded in detecting a part-through semi-elliptical crack as small as 0.2 mm deep initiating from the notch root.
Using this system, the crack initiation and following propagation behavior in the vicinity of a notch root in 3.5Ni-Cr-Mo-V steel in an aqueous environment were investigated.
Experience with Automated Fatigue Crack Growth Experiments
Authors: Van Der Sluys WA , Futato RJ 
Published: December 2008

The experience of the authors with the automation of the fatigue crack growth experiment is described. The system is described from both the hardware and the software standpoints.
The approach used in automating the fatigue crack growth experiment was to make as much use of the computer as possible by writing large, user friendly, multipurpose program systems. The approach has been very successful based on four years of experience in conducting experiments. High quality results have been obtained from experiments conducted by personnel not skilled in computer programming.
A Microprocessor-Based System for Determining Near-Threshold Fatigue Crack Growth Rates
Authors: McGowan JJ , Keating JL 
Published: December 2008

A microcomputer-based system has been developed to perform near-threshold fatigue crack growth testing. The crack length is measured by both potential-drop and compliance techniques. The potential-drop technique has a resolution of 0.0005 W and is used for real-time load control. The compliance technique has a resolution of 0.002 W and is used for comparative reference. The potential-drop system uses d-c current and has multiple voltage probes (located remote from current input points) to minimize the effects of current variation and resistance changes. The potential-drop measurements are made with and without excitation to minimize thermal offset problems. Compliance and potential-drop measurements are determined at specified load points during a cycle to minimize the effects of crack closure.
The system is programmed to control the rate of ΔK change (for increasing or decreasing ΔK tests) to a user-selected value. As the applied load is changed, the sample points (for measuring compliance and potential drop) during the cycle are changed automatically. A real-time sliding-seven-point fatigue crack growth rate calculation is performed for each sample. The sampling frequency is adjusted by the system during the test to maintain measurement accuracy. The microcomputer records crack lengths, loads, cycle number, and specimen temperature on floppy disks for post-processing.
Near-threshold fatigue crack growth results are presented for Type 304 stainless steel at both 24 and 538°C.
Analysis of Errors in Guarded Hot Plate Measurements as Compiled by the Finite Element Method
Authors: Troussart LR 
Published: December 2008

The object of this research was to study the effect of various design parameters of a guarded hot plate (GHP) on the error of measurement due to gap unbalance without having to resort to simplifying assumptions as has been the case in existing analytical studies. A better knowledge of this effect could lead to better national standards. It could explain some of the discrepancies often found between the results of round-robin tests. The method used is the finite element (FE) method applied to an axisymmetric GHP. The latter choice is justified by the fine discretization of the domain which is achievable without requiring a huge computer memory. This feature allows us to study the influence of thermopile wires crossing the gap.
The results show that for a given gap unbalance, one is not free to arbitrarily choose the thermopile wire diameter, nor the temperature drop across a given specimen thickness, if one seeks accurate measurements. One cannot achieve precise measurements with one apparatus and only one set of operating conditions that would apply to a broad range of thermal conductivities.
The value of the FE method to solve the differential equation of heat conduction while satisfying the operating boundary conditions of the GHP apparatus is also demonstrated.
Heat Flux Sensor Applications for Below-Grade Energy Studies
Authors: Shipp PH 
Published: December 2008

The use of heat flux sensors for energy studies of below-grade building envelopes and soil heat transfer is discussed. In a two-year study of three basements, heat flux sensors provided valuable information about local variations over the envelope surfaces. For complex building geometries, experimental designs that combine calorimetric monitoring of energy consumption with envelope heat flux profiles from heat flux sensors offer the most efficient means of determining building thermal performance.
The results from heat flux sensors buried in the soil were less satisfactory as the measurements were difficult to interpret because of the variability of soil thermal properties and the sensors' inability to detect vapor transport phenomena. Localized distortions caused by differences between the thermal conductivities of the sensors and their surroundings were found to affect heat flux sensor output significantly.
Significant differences between locally determined and factory supplied calibration values illustrate the need for improved standardization and disclosure of calibration procedures.
Calculation of Thermal Conductance Based on Measurements of Heat Flow Rates in a Flat Roof Using Heat Flux Transducers
Authors: Hedlin CP 
Published: December 2008

Heat flow rates through 60-mm-thick rigid mineral fiber insulation mounted in the flat roof of an outdoor test facility were measured with heat flux transducers. The temperature differences across the insulation were measured simultaneously with thermocouples.
Three different analytical procedures were used to calculate the thermal conductance of the insulation: (a) the ratio of heat flow rate to temperature difference, (b) the slope of heat flow rate as a function of temperature difference and mean temperature, and (c) transfer functions. The results obtained with these three methods are compared.
The effect of ignoring thermal lag was estimated for the first two methods.
Characterization of Submicrometre Surface Layers by Indentation
Authors: Pollock HM , Maugis D , Barquins M 
Published: December 2008

With our instrument, the penetration depth of a three-faced indenter is continuously measured during both indentation and unloading. Useful loads are about 10 μN to 30 mN (1 to 3000 mg). The specimen can be transferred between two locations (test and microscopic observation); a particular area can be relocated by means of a computer-controlled three-dimensional movement. Scratch hardness testing with measurement of frictional force can be performed at speeds as low as 30 nm/s. The general shape of the depth/load graphs, together with measurement of hysteresis and slope, gives an initial characterization of the specimen. Further analysis involves various theoretical topics, which we review in the light of recent literature. These include the way in which a variation of yield stress with depth will affect the measurements and the surface effects, such as the contribution of surface energy to the effective applied load. A controversial topic is the extent to which the depth of indentation in metals, relative to the mean distance between preexisting dislocations or grain boundaries, can lead to a true size effect, or even a critical load below which no plastic deformation occurs. Indentation creep may be significant even for metals such as steel and nickel at ambient temperature.
Accordingly, the concept of microindentation hardness as a material property can be of doubtful value for depths in the 10 to 100-nm range; the apparent mean pressure can be characteristic of a depth much greater than that of the plastic indentation. However, it is still possible to obtain measurements within this depth range, to deduce the type of regimen (for example, elastoplastic or fully plastic), and to derive alternative semiempirical indexes of the extent of plastic deformation, elastic recovery, and time-dependent behavior.
Use of the Automatic Capillary Rheometer in Quality Control
Authors: Sholley CK 
Published: December 2008

Manufacturing problems can be classified into two distinct categories: first, problems caused by equipment or process variables such as operating temperatures or pressures, screw speeds, die, screw and mold design, injection times, and so forth. The second category is problems caused by differences in the flow characteristics of resins and compounds (material variables). This paper will address the second category of material differences and show how they can be detected before processing through use of an instrument such as the automatic capillary rheometer (ACR).
The test method historically used for ensuring resin and compound uniformity has been the melt indexer or melt plastometer. The melt index test, however, is limited in relating polymer flow properties to actual processing conditions. It provides information only at low shear rates. Actual factory processes, such as calendering, extrusion, injection molding, transfer molding, and so forth, are performed under moderate to high shear rate conditions. The ACR is capable of measuring the viscosity of resins and compounds over the total range of processing shear rates thereby providing information relative to actual processing.
Use of the ACR in a quality control environment will be discussed along with data interpretation.
Biological Effects of Corrosion Products from Metals
Authors: Merritt K , Brown SA 
Published: December 2008

Metallic implants inserted into the body will eventually undergo some degradation by a variety of mechanisms including abrasion and corrosion. The biological effects of the material released into the tissue is a subject of much concern and investigation. We have been investigating the ability of the metallic implants upon degradation to stimulate metal sensitivity reactions, and studies have been undertaken in humans and animals to investigate the tissue response to metallic implants in the presence of metal sensitivity. It is apparent that many patients have a sensitivity to the metals in the implants and that the presence of metals in a sensitive animal or human will elicit inflammatory responses and sometimes the formation of foreign body giant cells. This may have an adverse effect on the performance of the implant with pain, swelling, and tissue necrosis at the site and, in some cases, loosening of the implant. Studies on implant site infections revealed that infection rates are altered by the presence of this tissue response.
Metal sensitivity reactions are not to the small metal ions but to a complex of metal ions and host tissue. The nature of the binding of the metal ion to tissue or cells, the distribution of the metal ion or metal complexes in the body, and the biological responses to these complexes are of concern. We have undertaken in vitro and in vivo studies on the binding of metal ions as metal salts or as corrosion products, and it is evident that metals bind mostly to albumin. The ability of these different metals to bind to red cells and white cells varies with chromium with a valence of 6+ binding most strongly to cells. The chrome from corrosion products binds strongly to cells and thus appears to be a chromium 6+.
Metal salts or corrosion products injected intramuscularly are rapidly distributed in the body with cell binding again being seen mostly with chromium 6+. Cobalt is not distributed as rapidly in the body and apparently binds to the tissue at the site of the intramuscular injection. The interaction of serum and cells with chromium on the surface of the implant may markedly effect its corrosion and the biological activity of the complexes formed. Some of the tissue and protein binding may be altered by shifts in the pH in the tissue during inflammatory responses or in infection.
Estimation of In Vivo Type 316L Stainless Steel Corrosion Rate from Blood Transport and Organ Accumulation Data
Authors: Smith GK , Black J 
Published: December 2008

A model utilizing implanted Type 316L stainless steel in laboratory rabbits was developed to investigate the systemic transport and distribution of constituent iron and chromium corrosion products. Results utilizing flameless atomic absorption spectrophotometry indicate that levels of circulating iron and chromium in the blood-transport compartment reflect the implanted surface area of Type 316L stainless steel. A similar positive correlation was found between implanted Type 316L stainless steel surface area and liver (reticuloendothelial) accumulations of iron and chromium. The kidney, having no reticuloendothelial capacity, demonstrated no constituent element accumulations.
Approximate corrosion rates of Type 316L stainless steel were calculated by: (1) superimposing the observed plasma iron elevations on transport compartment size and plasma iron kinetics, and by (2) evaluating storage site accumulations of iron and chromium over time. All calculations are consistent with Type 316L stainless steel's reported corrosion rate as measured by more precise in vitro and in vivo analytical techniques (20 to 300 ng/cm2/day).
Although the clinical significance of these findings is presently indeterminable, it is clear that the biological system as a whole must be considered when assessing the longterm biocompatibility of implanted Type 316L stainless steel.
In Vivo Degradation of a Polyurethane: Preclinical Studies
Authors: Parins DJ , McCoy KD , Horvath N , Olson RW 
Published: December 2008

In vivo investigation of a polyether polyurethane for possible use as pacing lead insulation material revealed surface degradation in the form of numerous cracks. The cracking phenomenon appeared to be stress related. Cracks were observed after three months implant time in rats and affected greater surface area with increasing implant time.
Toxicological investigation of the host animals revealed no adverse effects attributable to the polymer cracking phenomenon.
Examination by scanning electron microscopy revealed cracking that raised concerns about the integrity of thin-walled pacing leads. Ambient controls and in vitro specimens did not develop surface cracks. Surface cracking was independent of weight averaged molecular weight (Mw) and was observed on all tested samples, the Mw ranged from 255 000 through 636 000. No significant change in Mw after implant could be detected.
Surface degradation of this polyurethane was reproducible in controlled animal studies.
Biological Effects of Continuous and Intermittent Dosing of Outdoor Experimental Streams with Chlorpyrifos
Authors: Eaton J , Arthur J , Hermanutz R , Kiefer R , Mueller L , Anderson R , Erickson R , Nordling B , Rogers J , Pritchard H 
Published: December 2008

Two outdoor experimental streams fed by water pumped from the Mississippi River were dosed with the organophosphorus pesticide chlorpyrifos (the active ingredient of Dursban® and Lorsban 4E® insecticides) for 100 days, and the responses of individual species and communities compared to those of a control stream. Chlorpyrifos was continuously metered into one stream whereas the other received 8 biweekly additions, each lasting 24 h, at 14 times the concentration in the continuously dosed stream. Therefore, nearly equal amounts of pesticide were introduced into each stream during the experiment. The biological study area of each stream was approximately 245 m long, contained a naturally colonizing plant and invertebrate assemblage, and was stocked with fathead minnows and bluegills. Measured system characteristics included macroinvertebrate drift and riffle benthos composition; fish survival, growth, reproduction, food habits, tissue residues, and AChE inhibition; and system functional process indicators (P/R ratios, biodegradation, nitrate and dissolved organic carbon [DOC] concentrations, and bacterial growth and heterotrophic activity).
The macroinvertebrate communities reacted similarly in the continuously and pulse-dosed streams. Species diversity decreased by equal amounts and was still decreasing at the end of the test. Crippling of fathead minnows and reversible acute toxicity symptoms (lethargy, tetany when startled) in bluegills were observed only in the pulse-dosed stream. Fish survived, reproduced, and grew equally well in all streams. There seemed to be good agreement between laboratory and field effect concentrations for fish and invertebrates. Functional process indices, with the possible exception of biodegradation, appeared unaffected and considerably less sensitive than other characteristics measured. The results of the project are discussed in relation to lab to field extrapolation and the need for further testing.