bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiation-Enhanced Diffusion of 63Ni in Nickel and in Copper
Authors: Schüle W 
Published: March 2009

Radiation-enhanced diffusion coefficients of 63Ni in nickel and in copper were determined between -100°C and +500°C after an irradiation with 1.85 MeV electrons which were obtained from a Van de Graaff generator. The diffusion coefficients were obtained by counting the activity of successive layers from the surface of single crystals which were removed by means of sputtering. The dislocation density of the crystals was smaller than d = 10-4 cm-2 and the evenness of the surfaces of the crystals was better than 20 Å.
It was found that the radiation-enhanced diffusion coefficients were approximately independent of the irradiation temperature in the “low” temperature regime, i.e. below about 100°C, and about 1.3·10-20 cm2·s-1 and 1.1·10-20 cm2·s-1 for nickel and copper, respectively. The replacement collision sequence number of dynamic crowdions was derived from these results and values of N ≈ 50000 and N ≈ 40000 were obtained for nickel and copper, respectively. The same values were obtained previously from measurements of the radiation damage rate.
The radiation-enhanced diffusion coefficients were obtained for “high” irradiation temperatures, dependent on the irradiation temperature, and were approximately in agreement with those obtained by computation assuming that the migration activation energy of interstitials was EIIM = 0.869 eV and EIIM = 0.584 eV for nickel and copper, respectively (for K = 6.3·10-10 dpa·s-1).
Dynamic crowdions can dissolve e.g. precipitates, and three-dimensionally migrating point defects can usually form precipitates.
Factors Influencing the Performance of Chain Saw Leg Protective Devices and Its Measurement
Authors: Arteau J , Arcand J-F , Turcot D 
Published: March 2009

Protective trousers and protective chaps are worn by chain saw operators to protect their legs. The protection is given by protective pads sewn on the clothing. These pads are an assembly of layers of fabrics made form high-strength fiber. Protective pads are tested using a gas powered chain saw according to the CAN/BNQ 1923-095 and the ASTM F1414-92a test methods which are similar. The threshold stopping speed is the performance criterion measured. The TSS is the largest motor or chain speed at which no cut through occurs.
Since 1987, the CAN/BNQ 1923-095 test method has been used. From the test results, several observations are made and useful conclusions are drawn on the test method, on the mechanisms of protection and on the trousers and chaps.
On the test method: the chain sharpness, the chain type, the angles of cutters, the condition of the clutch, the gasoline and oil mixture and its stability are factors that affect significantly the measurement. The most important one is the chain. The findings are useful for any cut resistance test method. The test method is reliable and gives repetitive results.
Three main mechanisms of protection are observed. They are: cut resistant material, clogging (jamming) material and chain stop material. Description and examples of each are given.
Test results on trousers and chaps were performed on North American and European products before implanting a certification program in Quebec and in Canada. The results show large variation in the performance of leg protective devices. Some are excellent, some are very bad offering nearly no protection even if labelled “safety trousers”. Tests and analysis of the textile show variation in the number of layers, in the fabrics and a lack of mechanical stability under washing. These facts support to need of third party certification program. In conclusion, the test method is reliable, sensitive to changes in the protective pads or changes in the chain conditions and giving always the same ranking. Three mechanisms of protection are identified and their use on specific clothing is suggested. End users are now able to find performing products that will protect adequately.
A Nondestructive Inspection Method to Determine Fatigue in Chemical Protective Suit and Shelter Materials
Authors: Bray AV , Stull JO 
Published: March 2009

This study demonstrated the initial feasibility of using nondestructive inspection (NDI) penetrant-based methods for detecting fatigue cracks and similar breaches of integrity in chemical protective clothing and shelter materials. Such a technique could provide a simple but direct means of determining remaining life in chemical protective suits and shelters. Chemical protective materials range from coated fabrics to highly engineered multi-layer, multi-film composites. Selected materials were tested using off-the-shelf penetrant systems normally used for inspecting metallic surfaces. Microscopy, biopenetration, and chemical permeation were used to verify the results of penetrant NDI testing. The selected materials were fatigued using a “Gelbo flex tester” to simulate wear and repeated flexing. Controlled diameter and depth punctures were also used to induce material defects.
Fluorescent penetrants applied to Teflon/Nomex or fiberglass/Teflon composite laminates formed large florescent halos around defects which had breached the top layer of Teflon. These easily observed halos show through the translucent coating and were the result of penetrant wicking into the fibrous center layer. The detection success for defects which breached the outer Teflon layer was virtually 100%. Halo indications were typically 7 mm in diameter for a 0.12 mm puncture defect--representing an amplification factor of over 50. When a fatigued sample failed biopenetration, the same fatigue level sample produced positive penetrant testing results. Penetrant NDI results also correlated well with chemical permeation results. Fluorescent indications were observed for controlled punctures which were half as deep as the material thickness. Other types of chemical protective suit and shelter materials were tested, including PVC and butyl coated fabrics. while halos occurred in some of these materials, background coloring of other materials caused interference with the technique.
Developing and Applying a Material Specification for NASA's Propellant Handlers Ensemble
Authors: Stull JO , Thompson KG , Vahdat N 
Published: March 2009

An evaluation program was undertaken to choose new materials for NASA's propellant handlers' ensemble (PHE) used in the operations involving the transfer of hypergolic fuels and other hazardous chemicals. NASA currently uses an encapsulating suit constructed of a chlorobutyl rubber/Nomex® material in conjunction with a liquid air self-contained breathing apparatus (SCBA). The inventory of 300 suits and SCBAs are subjected to approximately 8000 wearings per year, and require an extensive maintenance and recycling program to ensure their continued effectiveness.
A review of existing NASA suit requirements and applications indicated a number of parameters important in the selection of the suit materials and seam construction. Other ensemble clothing items such as visors, gloves, boots, and suit closure systems were also considered. Performance criteria were developed based on existing NASA specifications and requirements in the National Fire Protection Association standard on vapor-protective suits (NFPA 1991). A life cycle cost analysis of the suits provided the range of material/suit costs based on expected service life. This information was used to develop a new specification that was submitted to industry for soliciting material candidates.
Baseline performance data were generated for the existing chlorobutyl rubber/Nomex material and related suit materials. A rating system was developed to assist selection and testing of replacement materials.
Stabilization of Heavy Metals in Portland Cement Matrix: Effects on Paste Properties
Authors: Bhatty JI , West PB 
Published: March 2009

Effects of heavy metals on the physical and chemical properties of cement pastes were studied using different types of cement, four metal oxides and four soluble metal salts. Type I (high aluminate content) and Type V (low aluminate content) cements were used to study the effects of their chemical differences on paste properties and metal stabilization. Fresh pastes were tested for workability, initial setting times, and heats of hydration. Hardened pastes were tested for strength and leachability by both TCLP and column leaching with acetic acid.
Initial setting times for pastes were significantly retarded by cadmium oxide and either form of lead and flow also decreased. Effects on setting time, slump area, and increased conduction calorimetry induction times are more pronounced with higher levels of lead and cadmium oxide. Addition of soluble chromium(III) chloride caused accelerated setting, higher paste temperatures, and smaller slump areas with both types of cement. In general Type V cement pastes with either soluble salts or oxides exhibit longer setting and induction times, and larger slump areas compared to Type I pastes.
Slow setting pastes had low three day strengths while fast setting pastes had high strengths at this age. However, the ninety day strengths of cement pastes is near control strengths for both Type I and Type V cements.
Leaching results were similar to those found by other workers. In these very cement-rich solids, chromium and cadmium were well stabilized but higher lead and mercury leaching was observed.
Evaluation of Alternative Drilling Technologies and Subsurface Confinement Barriers for Single Shell Tanks at Hanford
Authors: Acheson WP , Towers TA , Wentzel KW , Johnson HR , Overbey WK 
Published: March 2009

Many of the single-shell tanks at Hanford are well beyond design life and are perceived as being in imminent danger of failure. Some of the tanks have already failed. Over the years, tank leaks and spills have contaminated the soils; the soil contamination raises issues about the characterization of the tanks, closure of the tanks, and the safety of the tank farms. This study investigated the application of conventional and innovative drilling techniques to the problems of soil characterization, monitoring, and barrier installation (both desiccant and physical/grout types) beneath the Hanford C tank farm.
An evaluation and ranking of twenty four types of drilling technologies included horizontal and directional drilling techniques developed by the oil and gas industry, the mining and minerals extraction industry, and others. The drilling technologies were evaluated for their ability to drill in unconsolidated soils, provide good horizontal and vertical position control, facilitate subsurface characterization and monitoring, and permit installation of subsurface barriers beneath individual tanks or beneath a tank farm. Barrier placement and soil stabilization for remediation applications presents many challenges, particularly at the Hanford Site.
For example, one facet of the study included investigation and concept development of barrier systems which could be installed beneath and around the tank farms with a minimum of excavation. The barrier concepts--existing, commercially available technologies--had to be suitable for the variety of soil conditions found beneath the Hanford tank farms. The barriers were also investigated for their ability to withstand chemical attack and seismic deformations, and for their ability to have the barrier integrity verified remotely.
The best barrier technologies and drilling systems were combined into seven integrated barrier systems which were evaluated and ranked for their suitability to the Hanford site, their ability to meet environmental constraints, the safety of personnel working on the site, and the ability of the barrier to withstand large and small tank leaks. Each of these seven systems were then evaluated in terms of relative amounts of material extracted, deployment time, and costs.
The two highest ranked barrier systems developed were a circulating air barrier and a cone grouting barrier. Both are candidates for quick deployment and application to single or multiple tank systems. Both systems are candidates for demonstration at a cold test at the Hanford site. Two other potentially applicable barrier systems were evaluated, permeation grouting from horizontal wells and fracture grouting. Both are candidates for continued development and demonstration.
In-Situ Slurry Wall Formation with the SoilSawࡊ Barrier System
Authors: Carter EE 
Published: March 2009

This new technology was designed to form high-quality “formed-in-place” barrier walls in soil in a more continuous and uniform manner than the two-step, excavate and replace, processes of conventional slurry trenching. Soils in the path of the device are pulverized in-situ and liquified by high-energy jets of a permeability modifying grout. The hardware then passes through the liquified soil under the pull of gravity. The soil/grout mixture hardens to form a plastic diaphragm wall. Walls can be formed from a variety of materials.
The bulk of the energy to cut and mix the soil is transferred to the soil work face hydraulicly by the slurry media itself. Massive energy transfer of over 2000 hydraulic horsepower (1500 kilowatts) supplied by oil field cement slurry pumps allows dramatic productivity rates. The production rate of the process is significantly reduced in highly cohesive soils. This paper presents an introductory look at a potentially useful new method of construction of large subsurface barriers and contrasts it with conventional methods.
Effects of Flow Rate and Rotational Speed on Performance of Two Rotary Atomizers
Authors: Salyani M 
Published: March 2009

A spray patternator was used to evaluate distribution patterns of the “Air-cone” and “Micromax” rotary atomizers. The atomizers were operated at combinations of three rotational speeds and three flow rates. Distribution patterns were obtained by recording the amount of collected water in the graduated cylinders. The Coefficient of Variation (CV) of the collected volumes was used as a criterion to evaluate the uniformity of the distribution patterns. Samples of the droplets were captured between two silicon oil layers and estimates of the droplet sizes were obtained by microscopy.
Both atomizers produced saddle-shaped patterns. The two halves of the patterns were different and flow rate and rotational speed affected their shapes. Droplet size decreased as flow rate decreased or speed increased.
Formulation and Delivery Systems for Enhanced and Extended Activity of Biopesticides
Authors: Devisetty BN , Wang Y , Sudershan P , Kirkpatrick BL , Cibulsky RJ , Birkhold D 
Published: March 2009

Biopesticides are formulated microorganisms such as bacteria, fungi, viruses, or more complex organisms such as protozoa and nematodes. While several commercial products based on microorganisms have been developed and registered under the Environmental Protection Agency (EPA), actual use of these biocontrol agents for protection of crops against insects, weeds, and plant pathogens has been limited and accounts for less than 2% of total pesticide use today. Factors contributing to this low usage include costly and inefficient production methods (especially for fungi and viruses), poor storage stability, and susceptibility to environmental degradation. These are caused by exposure to temperature and pH extremes, desiccation, moisture, proteolytic enzyme activity from both plants and resident microbes, and ultraviolet (UV) radiation. Other factors contributing to the limited usage of biopesticides are: susceptibility only at specific development stage of target pest or weed, slow action for infectivity and mortality, requirement for specific environmental conditions for efficacy, and need for thorough spray coverage. Despite these limitations, industry is commited to the development of biopesticides as environmentally friendly alternatives to synthetic chemicals. This may be the result of public concern and demand to significantly reduce or even eliminate the pesticide residues in the food chain, rapid and excessive development of pest and disease resistance to chemicals, and high costs associated with the development and registration of a new chemical active ingredient.
Significant progress in formulation and application method has been made to protect the biopesticides from environmental degradation. These developments include: non-aqueous formulations, incorporation of UV protectants, starch and sodium alginate encapsulation, and adjuvants for wash-off resistance, humectancy, increased infectivity, and enhanced activity. In addition, genetic engineering technologies, such as bioencapsulation and transgenic plants have been designed to protect and extend the activity of Bacillus thuringiensis. This paper will review the work done in the area of formulations and delivery systems to enhance and extend activity of biopesticides. Primary emphasis will be on Bacillus thuringiensis, which represents more than 90% of today's biopesticide market for agronomic crops, forestry, and aquatic pest control.
Fluorescence as a Tool for Optimizing Adjuvants with a Photosynthesis-Inhibiting Herbicide
Authors: de Ruiter H , Uffing AJM , Meinen E 
Published: March 2009

The first objective of the study was to investigate whether measurement of leaf fluorescence can predict the inhibition of plant growth by the herbicide metoxuron. The second objective was to investigate whether fluorescence can be used as a tool for optimizing adjuvants for metoxuron. Metoxuron inhibits photosynthesis and as a consequence increases leaf fluorescence. Fluorescence was used to monitor metoxuron activity shortly after foliar application to common lambsquarters (Chenopodium album L.), black nightshade (Solatium nigrum L), and pea (Pisum sativum L.).
Varying the dose of commercially formulated metoxuron (wettable powder) demonstrated that fluorescence, measured 3 h (for common lambsquarters and pea) or 24 h (all species) after treatment, correlated well with the reduction of fresh weight determined 8 to 14 days after treatment. In order to optimize an emulsifiable rapeseed oil for metoxuron, we varied the concentration of emulsifier (polyoxyethylene C13/C15 oxo alcohol) in the oil (2.5, 10, and 40% w/v) and the concentration of emulsifiable oil in the spray solution (0.001, 0.01, 0.1, and 1% v/v). Generally, the concentration of the oil adjuvant in the spray solution was much more relevant to metoxuron activity than the emulsifier content of the oil. In common lambsquarters and in black nightshade the lowest concentration of oil tested (0.001%) was effective. In pea, the oil was effective at 0.01% and above. The fluorescence measurements with the metoxuron-adjuvant combinations correlated well with the influence of these combinations on the reduction of fresh weight of the species.
We conclude that fluorescence can be a rapid, accurate, and time-saving tool for the comparison of adjuvants or formulations for photosynthesis-inhibiting herbicides.
Weathering and the Performance Equation: Moving Towards Visual Standards
Authors: Atkinson B 
Published: March 2009

Performance codes are now in use internationally after a twenty-year eriod of gestation. The performance equation and its philosophy is introduced and its relationship with the current performance concepts described. Its original use as a generic framework for research into the performance of the external fabric is outlined.
Standards lend themselves readily to numerically defined phenomena. The ubjective nature of some weathering causal factors and the difficulties of measuring these are highlighted. The decision to restore the appearance of architectural buildings falls into this category of preservation. Visual changes lack definitive descriptors, but the paper reviews those available causal factors that would be useful in modeling the phenomena. Each major descriptor such as precipitation and pollution, and their components are considered in turn. Recognized patterns of surface soiling are presented.
It is held that Preservation standards related to changes in appearance begin with studies of rainfall and particulate distributions over buildings. Measures of aesthetic or visual failure are required because these processes have to eventually form a valid part of a preservation philosophy; and need to be covered by performance codes. By their longevity and example, historic buildings provide a laboratory of case studies. The paper suggests that standardization of visual change will involve standardization of interactive modeling techniques rather than direct testing.
Compatibility and Retreatability Versus Reversibility: A Case Study at the Late Hellenistic Nymphaeum of Sagalassos (Turkey)
Authors: VanBalen KEP , Ercan S , Patricio TC 
Published: March 2009

Anastylosis has been used as the conservation method for the late-Hellenistic Nymphaeum at the archaeological site of Sagalassos (Turkey, Prov. of BURDUR). The original fragments of the U-shaped fountain building have been excavated, and restored, with missing parts completed as a step towards reassembling all of the building fragments necessary to restore the structure. Materials and techniques used for the gluing and completing of the different stone fragments have been chosen based on the general principle of retreatability leaving aside the generally accepted use of ductile materials for reinforcement. This choice has been made despite the fact that in structural engineering ductility is often used as an additional safety domain. The technique of reinforcement and reconnecting fragments was based on the use of epoxy binder and fiberglass bars. This solution creates a brittle behavior at ultimate strength of those structural components which is less than the strength of the stone and therefore guarantees possible retreatability.
The results of preliminary tests, the application at the site on the building and the final result of the Anastylosis are presented.
An Instrumented Geogrid Reinforced Slope in Central Italy: Field Measurements and FEM Analysis Results
Authors: Montanelli F , Recalcati P , Rimoldi P 
Published: March 2009

A 15 m high green faced reinforced slope was built in 1996 to stabilise a landslide situated on the Montone hill in the province of Perugia (Italy). The reinforced slope was built using locally available soils as fill material and HDPE mono-oriented extruded geogrids as reinforcement. The reinforced slope has been instrumented with strain gages connected to the reinforcing geogrids and with total pressure cells; full scale in situ pull-out tests have been performed as well.
The preliminary results demonstrate the good performance of the geogrids and define possible failure mechanisms for slopes with stepped geometry. The in situ pull-out test results validate laboratory tests performed in the past. To evaluate the field stress and deformation behavior of the reinforced slope a finite element analysis has been carried out. The paper describes the model technique developed to evaluate the field stress and deformation of steep reinforced slope using special interface elements. The results of finite element analysis are in agreement with the field measured results.