bluuebunny/crossref_metadata_2025_split huggingface dataset:
Local Stresses in Metal Matrix Composites Subjected to Thermal and Mechanical Loading
Authors: Highsmith AL , Shin D , Naik RA 
Published: March 2009

One of the important damage mechanisms in metal matrix composites is fiber/matrix separation. The interfacial region between the fiber and matrix is typically brittle and relatively weak, and therefore failure in this region may precede failure of the fiber and matrix. An elasticity solution has been used to analyze matrix stresses near the fiber/matrix interface in continuous fiber reinforced metal matrix composites. This micromechanics model consists of a cylindrical fiber and cylindrical sheath of matrix embedded in an orthotropic media representing the composite. The micromechanics model is used to predict thermal and mechanical properties for a lamina. These properties are then used in a laminate analysis to determine ply level stresses caused by a thermomechanical loading of the laminate. Finally, for a given ply, the ply level stresses and thermal loading are used in the micromechanics model in order to predict local stresses near the fiber/matrix interface.
Predictions from the closed form micromechanics model, which assumes cylindrical symmetry, have been compared to predictions from a finite-element model in which the fibers are arranged in a square array. Near the interface, stresses predicted by both models are in reasonable agreement. The micromechanics model was also used to predict the onset of fiber/matrix separation. Model predictions for a variety of laminates were in reasonable agreement with experimental data.
Morphology Dependent Resonance Measurements of Berglund-Liu Generator Droplet Dispersion
Authors: Bayvel LP , Driver HST , Knight JC , Robertson GN 
Published: March 2009

This research exploits the well-documented morphology dependent resonances (MDRs), observed from lasing spherical droplets in the supermicron range, for highly accurate measurements of the size of droplets produced by the Berglund-Liu vibrating orifice mono-disperse aerosol generator. The measurement is several orders of magnitude more accurate than established methods.
Single dye-doped ethanol droplets, in the size range a = 15 to 45 μm, of known refractive index, from a nominally monodisperse distribution, were illuminated with the green frequency doubled beam of a single-longitudinal-mode neodymium: yttrium aluminum garnet (Nd: YAG) laser, and scattered light was collected at 90° to the incident beam. The collected light was dispersed and detected on an optical multichannel analyzer. The recorded spectrum is the broadband fluorescence spectrum, modulated by the regularly spaced MDRs, which act as wavelength-selective high-Q, cavities. At high values of the input intensity, the cavity provides positive feedback and amplification, characteristic of laser radiation. The smooth temporal profile associated with a single-longitudinal-mode laser improves signal-to-noise ratios above those achieved in previous work using a multimode pulsed laser. A good signal-to-noise ratio is vital if accurate information about droplet size is to be gained.
The study of the wavelength locations of the observed MDRs can provide highly accurate measurements of the droplet size and size variations. The accuracy of these measurements is limited only by imperfect knowledge of the refractive index, by asphericity of the illuminated droplet, and by experimental resolution and noise levels. Advantages over established methods include the high-speed, nonintrusive nature of the measurement and greatly improved measurement accuracy.
A Multiple Drop-Size Drop Generator for Calibration of a Phase-Doppler Particle Analyzer
Authors: Dressler JL , Kraemer GO 
Published: March 2009

A multiple drop-size droplet generator was developed for Lycoming to calibrate spray measurement instruments with respect to drop diameter. The droplet generator can simultaneously produce one, two, or three drop diameters in the range of 50 to 450 μm. Drop diameters have temporal variations less than 1%, and each drop-size species is monodisperse to within 1%. Measurements of the spray produced by the multiple-size drop generator made with a properly aligned phase-Doppler particle analyzer, whose gain setting was optimized to reduce spurious validations about the largest diameter, gave accurate diameter readings within one or two measurement size classes or cohorts (2 to 4%). Transmitter lens spherical aberrations gave errors typically less than 3%.
Stimulated breakup of liquid jets, commonly called Rayleigh breakup, creates the droplets. Liquid, flowing from a pressurized manifold through orifices in a laminated nickel and copper plate, forms the jets. Piezoelectric transducers perturb the jets' velocity, breaking the jets into drops at the frequency of the velocity perturbations. Subharmonic velocity perturbations cause controlled agglomeration of the drops increasing the final droplet diameter and spacing. A stroboscope makes the droplets appear stationary for photographs and optical size measurement. Electrically charging the droplets creates a dispersion of controllable magnitude of the spray and a few reverse flow particles. Dividing the flow rate by the drop production frequency accurately determines the drop volume. The inexpensive and easily changed orifice plates contain 21 orifices spaced on a 2.54-cm line. Orifice diameters can be any size greater than 10 μm. In multiple diameter plates, the larger diameters are integer multiples of the smallest diameter.
Optical and Electronic Limitations of the Forward-Scattering Spectrometer Probe
Authors: Baumgardner D , Cooper WA , Dye JE 
Published: March 2009

An extensive evaluation of the optical and electronic measurement capabilities of the Particle Measurement Systems, Inc., forward-scattering spectrometer probe (FSSP) has led to a better characterization of this probe's measurement limitations. Measurements of droplet distributions are distorted as a result of mis-sizing and undercounting by the FSSP. These measurement errors have been traced to limitations imposed by the response time of the electronics, intensity inhomogeneities of the laser beam, and optical coincidence.
The optical and electronic characteristics of the FSSP have been mathematically modeled, and algorithms have been derived for the application of corrections that improve the accuracy of the measurements from these probes. These correction procedures adjust the measured concentrations for the effects of coincidence and deadtime losses and adjust the size distribution for undersizing caused by response time rolloff and laser beam inhomogeneities. This presentation summarizes the operational limitations of this instrument.
Characterization of Aerial Spray Nozzles with Laser Light-Scattering and Imaging Probes and Flash Photography
Authors: Picot JJC , van Vliet MW , Payne NJ , Kristmanson DD 
Published: March 2009

Laser light-scattering and imaging probes plus a flash photography system were used to count and measure droplets from a multiple-jet, nozzle-in-boom system with the jets facing downstream in an airflow. Tests were done in a laminar flow wind tunnel. The method of incorporating data from these different measuring systems is explained. The droplet diameter range measured was from 0.5 to 3600 μm. Tests cover air speeds ranging from 11 to 54 m/s, fluid flows from 1.8 to 8.8 L/min per nozzle, for 10-to 30-jet arrays per nozzle with jet inside diameters (ID) from 0.76 to 1.8 mm.
A correlation obtained for the volume median diameters from 14 tests shows good agreement with experimental data, for the single fluid studied: log10[Dv0.5/d0]=3.71-0.303log10-0.746log10We where d0 is the jet ID, Re is defined for the flow through a single nozzle, and We is based on d0 and the relative velocity of liquid to gas at the nozzle.
Is There an Anesthetic Contribution to Ozone Depletion or Greenhouse Warming?
Authors: Joyner BD 
Published: March 2009

Chlorofluorocarbons (CFCs) are firmly linked with stratospheric ozone depletion and potential global atmospheric warming—the greenhouse effect. Halogenated anesthetics—halothane, enflurane, and isoflurane—are superficially similar in chemical structure to CFCs, and concern has been expressed regarding their possible contribution to the same environmental issues.
The historical development of both concerns is traced, together with the chemical structures of the highly stable CFCs and of the less stable substitute materials now under development. From this information it is shown that any conceivable contribution to either issue by halo-genated anesthetics would be absolutely minimal.
On a production volume basis alone, the annual world production of anesthetics is about one thousand times less than that of CFCs. In addition, the chemical structures of anesthetics show much more similarity with the “environment-friendly” substitutes for CFCs than with CFCs.
Anestheticography: Clinical Applications
Authors: Jantzen J-PAH 
Published: March 2009

The safe practice of inhalation anesthesia requires control over the amount of volatile anesthetic delivered to the patient. This is facilitated by continuous monitoring and recording of the agents' concentration (“anestheticography”). Either the vaporizer or the circuit may be considered the “delivery system,” hence anestheticometry performed either in the fresh gas supply or in the inspiratory limb of the system is acceptable. Such monitoring practice may be expected to eliminate anesthesia-related death due to overdose of volatile agents. Besides the aspects of technical safety, anestheticometry is a useful adjunct to teaching and research. It supports a more widespread application of the minimal-flow and closed-circuit techniques, facilitates the understanding of inhalation anesthesia, and increases acceptance of low-flow systems. For minimal-flow anesthesia, anestheticometry should be considered mandatory because it provides the only means of detecting and correcting derangements of the anesthetic vapor concentration, often brought about by routine clinical maneuvers.
To demonstrate this, we recorded the course of the inspiratory and expiratory concentration of a volatile anesthetic (isoflurane) by infrared absorption and a trend recorder. Changing the carrier gas composition during high flow (fresh gas flow = 6.0 L∙ min-1) from 75 to 25 vol % nitrous oxide in oxygen resulted in a 10% increase of the inspiratory isoflurane concentration. Activating the oxygen bypass or exchanging the soda lime canisters was followed by a prolonged reduction of concentration, most pronounced with minimal flow (fresh gas flow = 0.5 L∙ min -1). Initiating emergence by closing the vaporizer during minimal flow led to a slow decrease in concentration, while at high flow the inspiratory isoflurane concentration rapidly decreased to subanesthetic levels. Integration of a charcoal filter into the inspiratory limb of the breathing circuit reduces the inspiratory concentration to undetectable levels within &lt;3 min. Anesthe-ticography is a useful means of monitoring and documentation of inhalation anesthetic. Such monitoring should become part of ISO standards for reasons of patient safety, economy, teaching, and research.
Economics of Anesthetic Gas Monitoring
Authors: Bray CS 
Published: March 2009

The purpose of this paper is to attempt to identify and quantify the cost differences in the United Kingdom (UK) between continuous-flow open anesthetic systems and low-flow closed systems. Due to the lack of reliable statistics, such an appraisal is difficult, and at best this paper can give only a likely indication of the actual costs involved. Costs will vary significantly from country to country, and a detailed study for any particular site is necessary if meaningful results are to be obtained.
Annual running costs for Raman laser, infrared, and piezoelectric type monitors have been estimated. A significant expense is the provision of the disposable gas sampling line, if it is changed in accordance with the manufacturer's recommended intervals.
An estimate is made of the money spent on volatile agents and anesthetic gases in the UK, and the potential savings from decreasing gas flow from 10 to 2 L/min. is also estimated. These figures are compared with the estimated cost of providing all operating theatres in the UK with anesthetic gas monitoring equipment.
Other factors such as additional expenditure on soda lime and savings on other monitoring equipment, e.g., oxygen analyzers, are taken into account.
The Pharmaceutical Price Regulation Scheme is briefly explained, as well as the likely effect of the scheme on savings in the use of volatile agents.
Suspension Systems for Today's Manufacturing Environment
Authors: Troxell JR 
Published: March 2009

Manufacturing today is going through a major change; two features of this change are the reduction or elimination of inventory (Just-In-Time) and a new, plant-wide emphasis on quality (Total Quality Control). One particular technique for never-ending improvement of quality is called line-stop, where operators on the production line have the authority to stop production when an indication of quality deterioration is observed.
Suspension systems are well-suited for the line-stop technique. A suspension system is the combination of a suspension rule, designated (j,k), and a lot by lot inspection plan; suspension occurs if j lots are rejected in k or fewer lots. A simple rule such as stop production if two lots are rejected within five or fewer lots (2,5) can be used, avoiding the use of perhaps subjective impressions by the operator concerning quality.
This paper reviews the characteristics of such rules, highlighting their mean time to suspension or Average Run Length. Suspension systems are compared to cumulative sum charts. Cumulative sum charts have shorter average run lengths, but not by much; suspension systems are easier to understand and easier to use, requiring no calculations at all in their daily use.
Sampling Plans with Low Consumers' Risk
Authors: Tye JB 
Published: March 2009

Most sampling activity is concerned with the Acceptable Quality Level (AQL) or Producers' Risk. There exists, however, applications for sampling schemes built around the Limiting Quality Level (LQ) or Consumers’ Risk. Examples include isolated lots or cases where the characteristic being examined in the sample is so severe that extra care must be taken to prevent nonconformances being shipped or used. When the output of nonconformances must be zero or measured in parts per million, a sampling scheme with low consumers’ risk can be effectively used to audit a process. It can be argued that this is a form of process control because rejection of a lot under this scheme is an indication of major problems. In such cases, diagnosis and corrective action are required immediately, in addition to the usual screening of the rejected lot and those immediately preceding it.
This paper provides such a sampling scheme. The determining parameter is the average outgoing quality limit (AOQL). LQ's from 0.001 to 0.05 are used. Because of the universal application and popularity of MIL-STD-105D and the ANSI Standard Z1.4 (Ref.), their format and procedure have been followed wherever possible.
Report of an Interlaboratory Study Comparing EPA SW 846 Method 3050[1] and an Alternative Method from the California Department of Health Services
Authors: Kimbrough DE , Wakakuwa J 
Published: March 2009

The existing EPA method for the analysis of toxic elements in solid matrices, SW 846 method 3050, cannot accurately or precisely determine (i.e., within SW 846 quality control limits) the concentrations of either antimony or silver and can do so for barium only at lower concentrations. An alternative method was developed by the Southern California Laboratory of the Department of Health Services that could (1) simultaneously solubilize all of the above elements over a broader range of concentrations and (2) solubilize all other regulated elements with equal or better results.
As a part of the validation process for this alternative method, an interlaboratory study was conducted. Nine public and private laboratories compared the existing method with our alternative method. The results of this study clearly show statistically significant differences between method 3050 and the alternative method proposed in this paper.
Modification of the TCLP Procedure to Accommodate Monolithic Wastes
Authors: Bone LI , Bricka M , Hannak P , Shah SI , Prange N , Marsden PJ , Waggener JE , Miller M , Johnson E , Robuck SJ 
Published: March 2009

The current EPA Toxicity Characteristic Leaching Procedure (TCLP), SW 846 Method 1311, requires that all wastes be milled into smaller particles prior to being placed into the extractor. A multi-laboratory study has been conducted to determine if milling is necessary or if the tumbling action of the TCLP procedure will cause monolithic wastes, which are not strong enough to survive in the environment, to fall apart in the extractor. Multiple plugs of eight different solidified waste samples of variable strength were prepared. The unconfined compressive strength of a plug of each sample was measured and the environmental survivability was evaluated in two separate laboratories using the ASTM Freeze/Thaw (D4842-90) and Wet/Dry (D4843-88) testing procedures. Identical plugs of each sample were tumbled in glass bottles, equipped with a stainless cage as proposed by EPA. Additional identical plugs were tumbled in unbreakable plastic bottles following the same protocol used with the stainless steel cage. Five separate laboratories performed the stainless steel cage experiments in duplicate while three laboratories performed the plastic cage tumble, also in duplicate. No chemical analysis was performed; each laboratory simply weighed the amount of material which would not pass through a 9.5 mm sieve after the 18-hour tumble was complete. This weight compared to the initial plug weight was compared with the freeze/thaw, wet/dry and unconfined compressive strength results.
All samples that had low strength and failed the wet/dry tests fell apart when tumbled in either type of container. Comparison of the cage and plastic bottle results clearly showed the plastic bottle to be superior. The results better matched the strength data, the data were more reproducible on both an intra- and inter-laboratory basis, and a plastic bottle is easier to clean. ASTM D-34 is drafting a leaching procedure similar to the TCLP which will use a nonbreakable bottle and will not require particle size reduction of the waste prior to tumbling in the extractor.
Sampling Protocol Development for Hazardous Waste
Authors: Eatmon BS , Marcus MF 
Published: March 2009

Many of the sampling devices, procedures and protocols used for hazardous waste sampling have been developed and adapted from water or soil sampling procedures. In every case significant modification and flexibility in these procedures are necessary to successfully sample hazardous waste material. A set of sampling protocols have been prepared by our operating sites to utilize our collective experience in sampling and to standardize our sampling protocols across our company. General sampling protocols were needed that address: Sample Training; Safety — Personal Protective Equipment; Chain-of-Custody/Labeling; Sample Management — Container, Preservations, Holding Times, and Sample Facilities and Decontamination.
These general protocols are the basis for development of specific sampling circumstances that are routinely encountered during the management of hazardous waste. These specific routines are called the Site Specific Protocols and they include: solids in drums; liquids in drums; bulk solids; bulk liquids; stationary tanks; surface impoundments; in-line liquids; waste piles; laboratory subsampling liquids; laboratory subsampling solids.
Early Warning Report: Automated Checking of QC Data
Authors: Peak SR , Duerksen PE , Wong KW , Szeto E 
Published: March 2009

Sample log-in, work list generation, data entry, and report production are data-handling functions common to most Laboratory Information Management Systems (LIMS's). A newly developed automated review system now extends those functions to include the use of a LIMS for reviewing and evaluating quality control (QC) results. This paper delineates the four major stages involved in creating this automated review system: concept, preliminary design, programming, and testing. Although computer programming is typically system-dependent, the logic employed in QC review should have broad application to many LIMS's.
The paper also describes the daily operation of this new LIMS function on-line in three networked commercial laboratories with over 140 employees. This account of the review system's pitfalls, successes, and maintenance requirements can help other LIMS users achieve a smooth, reliable installation.
Fracture Toughness Evaluation of Heat-Treated Zr-2.5Nb Pressure Tubes
Authors: Asada T , Kimoto H , Chiba N , Kasai Y 
Published: March 2009

Tests of full-size pressure tubes and compact tension specimens having several widths are carried out with emphasis on the size effect on the fracture toughness of the pressure tube material, which is made of heat-treated Zr-2.5Nb. The hydrogen concentration of the specimens ranges from 10 to 400 ppm, and the test temperature from room temperature to 573 K.
In the pressure tube burst tests at room temperature using radial hydrided materials, fracture toughness at maximum pressure KC decreased rapidly with hydrogen concentration in the region where the concentration was less than 100 ppm. In the region where the hydrogen concentration was higher than 100 ppm, KC slowly decreased with increased concentration. For materials having radial hydrides at a hydrogen concentration of 200 to 300 ppm, a steep brittle-ductile transition was observed at about 550 K.
Fracture toughness KC shows strong dependence on specimen size, increasing and approaching that of pressure tubes with increased specimen width for a ductile material. This size effect of fracture toughness can be determined by a failure assessment method in which the Dugdale model is used.
Growth in Zircaloy-4 Fuel Clad Arising from Oxidation at Temperatures in the Range 623 to 723 K
Authors: Donaldson AT 
Published: March 2009

Tubular samples of Zircaloy-4 clad, of the standard 17 × 17 PWR design, in the cold worked, stress relieved condition, with a mean wall thickness ξ = 580 μm, and samples machined to reduce their wall thickness to 200 and 80 μm, respectively, have been oxidized in air at one bar pressure for exposure periods up to 753, 195 and 152 days, at temperatures of 623, 673 and 723 K, respectively.
Oxidation produces tube lengthening that increases with exposure time and temperature and varies inversely with clad wall thickness. The rate kinetics of oxidation induced straining mirror those of the weight gain measurements. Axial strains up to εz = 0.0265, 0.0185 and 0.0016 in the thinnest clad, and 0.0047, 0.0014 and 0.0003 in standard clad, are observed following exposure at 723, 673 and 623 K, respectively.
A model is developed in which the observed length variation, εz, is expressed in terms of the weight gain owing to oxidation, Δw, the exposure temperature, T, and clad thickness, ξ, according to (ϵz/Δw)=A⋅(ξ)m where the coefficients A and m vary with temperature.