bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preventive and Design Measures for Protection Against Dust Explosions
Authors: Bartknecht W 
Published: December 2008

There is an inherent danger of a dust explosion when combustible dusts are handled in industry. This is proven by the many explosions which have resulted in substantial losses and often in fatalities. To counteract danger it is important to know the safety characteristics of the dust deposits or dust cloud. Based on the test methods used, it can then be decided which of the available protective measures should be applied. A distinction has to be made between preventive and design measures for the explosion protection.
Preventive measures avert a dust explosion by:
• preventing the formation of an explosible dust/air mixture, • inerting or removing oxygen, and • eliminating effective ignition sources.
Design measures will not prevent a dust explosion, but they will limit consequences to an acceptable level.
They include:
• explosion-resistant design for the maximum explosion pressure, • explosion-resistant design for the reduced maximum explosion pressure in conjunction with explosion pressure venting or explosion suppression, and • means to divert the explosion from entering peripheral equipment.
A general overview is given of all protective measures and the necessary decision making criteria.
Monitoring, Research, and Management: Integration for Decisionmaking in Coastal Marine Environments
Authors: O'Connor JS , Flemer DA 
Published: December 2008

A rationale is presented for making research and monitoring interdependent to maximize the contributions of both activities to environmental management. Emphasis is placed upon better choices of temporal and spatial scales of marine assessments, thereby improving managerial guidance from monitoring and research. While appropriate scales are functions of particular environmental issues, the most useful scales “in the mean” appear to be long-term (including truly historical) and regional. The likelihood in the near-term of only limited incremental advances in understanding ecosystem processes, with marginal improvements in predictability, leads to an argument for more emphasis upon the use of managerially helpful, necessarily simple models. One such model is presented, to characterize the geographical prevalence of fin erosion in winter flounder (Pseudopleuronectes americanus), relative to the sources of plausible causes, from Canada to Delaware Bay. Changing emphasis from laboratory bioassays to field population-level effects is an important and essential step toward integrating ecosystem-level knowledge into the managerial and regulatory milieu.It is now possible to quantify the geographic and, at least recent, temporal associations among man's waste sources and some of their biological effects. Further elaboration of source-fate-effects understanding with the help of simple models (for example, indices) is often more useful to managers than is detailed, piecemeal quantification of seemingly intractable ecosystem dynamics.
Estuarine Invertebrates and Fish: Sampling Design and Constraints for Long-Term Measurements of Population Dynamics
Authors: Hines AH , Haddon PJ , Miklas JJ , Wiechert LA , Haddon AM 
Published: December 2008

The first five to six years of a long-term data set are presented for invertebrates and fish representing an array of physiological tolerances, trophic levels, and life history strategies in a lower mesohaline subestuary of Chesapeake Bay. Population abundances were estimated for infaunal invertebrates with cores taken four to six times per year at five stations, for nearshore fish with seines taken once per year at 14 stations, and for epibenthic fish and crabs taken in trawls eight times per year at three stations. Physical/chemical parameters of estuarine water were monitored continuously. Analyses of variance and covariance were used to account for variation associated with seasonal cycles and to test for effects of year, station, and salinity on population abundances.
A 16-year record of meteorological and water parameters showed that the study period spanned a multiyear period of regional drought in the 1980s, which resulted in markedly increased salinities and reflected a greater deviation from the long-term average than reduced salinities during major storms of the 1970s. ANOVA and ANCOVA models accounted for 12 to 82% of the variation in population abundance, depending on the species. All but two species showed significant differences in population abundances among years in six years' data for 19 infaunal invertebrate species, six years for 18 species of nearshore fish, and five years for five species of epibenthic fish and crabs. Most species exhibited severalfold differences in abundance among years. About half of the infaunal species, several of the nearshore fish, and four epibenthic species showed significant responses to elevated salinities. However, despite the overall importance of salinity on estuarine systems, only a small fraction (1 to 6%) of the variation in any one species was explained by salinity changes. Failure to account for more of the population variation by salinity resulted from: (1) the significant spatial (station) variation and the significant interaction of time and spatial variation in nearly all species; (2) the importance of other meteorological and water quality parameters in regulating populations; (3) salinity being important primarily during a critical period (for example, during spring recruitment) because other factors (for example, predation) may override the controlling influence of salinity during the other seasons; (4) the spatial scale of the study area being too small too exhibit major shifts in species abundance across the major salinity zones of the estuarine gradient; (5) the location of the study area at the low end of the mesohaline zones means that high salinities dominating the study period are unlikely to affect euryhaline species as much as low salinities; and (6) possible biases of short-term variation since most years of the study perios were characterized by unusually high salinity.
Development, Management, and Analysis of a Long-Term Ecological Research Information Base: Example for Marine Macrobenthos
Authors: Michener WK , Feller RJ , Edwards DG 
Published: December 2008

As one of eleven Long-Term Ecological Research Program sites in the nation (designated by the National Science Foundation), the Belle W. Baruch Institute for Marine Biology and Coastal Research has developed a flexible system for the management and analysis of ecological data. The Baruch Data Management System (BDMS) contains over four years of data collected from ecological research on coastal and estuarine habitats. Important design features of information bases for long-term monitoring are described.
Since temporal variability is an inherent part of ecological data sets, it is important to delineate those periods when sampling must be intensified and periods when sampling can be decreased without compromising documentation of the processes under question. Examples of analyses of temporal variability for one of the biological data sets (macrobenthos) are presented, and a case is made for the importance of long-term monitoring efforts to the generation of process-related experiments.
The Use of Modern Atomic Spectroscopy in Industrial Analysis
Authors: Savolainen A , Griffin H , Olear G 
Published: December 2008

Industrial laboratories are being forced to develop faster, more accurate and precise but less expensive analytical methods. This paper describes one laboratory's learning process over the past 20 years. The changes that occurred by changing from wet chemistry and arc/spark emission spectroscopy to atomic absorption spectrometry to manual and then automated plasma spectroscopy are described. The rationale of choosing a particular plasma spectrometer is explained along with how to automate specimen introduction, computerize data collection, and display results of a running analysis. An algorithm used to improve results is also described.
A number of different methods that were developed for the new methodology are described. These methods cover a wide range of topics such as plating bath analysis, steel analysis, precious metals analysis, comparisons to fire assaying, analysis of impurities in titanium dioxide (TiO2), and solders. Along with these methods are some time studies that demonstrate the economic rational for buying this type of instrumentation.
Microprocessor-Based Determinator Design and the Impact of Future Trends in the Area of Computer-Controlled Automation of Analytical Chemistry Methods
Authors: Fricioni RB 
Published: December 2008

The design of analytical instrumentation has always made use of the latest electronic technology to provide the fastest and most accurate methods for analysis. The present and the future is no different than the past. Computer and microprocessor technology offers solutions to analytical problems that until this period of time had to be lived with.
Designers, while holding on to basic analytical techniques, cannot incorporate corrections for previously known but uncontrollable factors. Computer and microprocessor based design offers the designer the capability of automating manual analytical methods that previously were simply too complex. The design of such systems follows the same exacting evaluation process as used in the past. Evaluations for the most efficient extraction, isolation or separation, detection, signal process, and systems control methods are made and compiled to result in a fast, accurate, and easy to use system.
The combination of electronics, electro-mechanics, and analytical methods is continuing with the advent and development of robotics. Combined with the technology of todays instrumentation robotics can offer further productivity and efficiency of the analytical lab.
Analytical Laboratory Information Management System (ALIMS)
Authors: Blair FA , Arritt JM , Lundy LJ 
Published: December 2008

A computerized system has been developed that closely approaches total laboratory data automation. The system is menu driven, permitting the analyst to easily step through a hierarchy of works instructions. Data generation, calculations, dissemination, and retention are fully automated for instruments and automated for wet-chemical analyses prior and subsequent to raw data collection.
The system begins with the log-in of samples for which unique identification numbers are automatically generated. The total routine workload can then be scheduled by the computer. Overrides permit appropriate variations. Work centers query the system for assignments. The system not only controls and monitors work flow but invokes analytical and quality control procedures as well. For management control, sample status is readily available.
Instruments controlled by the system include inductively coupled plasma, atomic absorption spectrophotometer, optical emission spectrophotometer (ICP, AAS, OES), analytical balances, LECO analyzers, ultraviolet-visible spectrophotometer (UV-VIS), and automatic titrators. Report capability exists for back-logs, sample status, quality control, cost accounting, and periodic performance.
Optical Properties of Infrared Transmitting Glasses
Authors: Mitra SS 
Published: December 2008

Considerable interest has recently been evidenced in infrared transmitting glasses for components such as laser windows, IR domes and IR optical fibers. In particular, multicomponent heavy metal fluoride glasses based on zirconium or hafnium have displayed desirable optical characteristics, viz., low refractive index, absorption and scattering losses, and a very wide spectral transparent regime, in addition to attractive mechanical and chemical properties.
This talk will review the optical properties of this and related metal halide glasses over the entire spectral range (9 μm to 260 nm). This will include review of experimental data for the ultraviolet absorption edge, infrared edge absorption and temperature dependence, and the understanding of the latter through fundamental vibrational spectra, information regarding which is obtained from a study of infrared reflection and Raman scattering measurements. Effects of nuclear radiation on the optical properties of a number of these glasses will be presented.
Laser Induced Bulk Damage in SiO2 at 1.064, 0.532 and 0.355 μm
Authors: Merkle LD , Koumvakalis N , Bass M 
Published: December 2008

In this paper we present bulk damage measurements of crystalline quartz and fused silica under single and multiple pulse irradiation where the wavelength was extended to 0.355 μm. In previous work under irradiation at 1.06 and 0.532 μm, it was shown that whereas the single pulse damage varies little with material or wavelength, the multiple pulse damage depended strongly on both. Also, in the case of multiple pulse damage the distribution of the number of pulses needed to produce damage as a function of intensity is indicative of an accumulation process.
If the present work at 0.355 μm the multiple and single pulse damage dependence on focal spot-size, pulse duration and pulse repetition frequency is examined, it is found that the multiple pulse damage shows a much stronger dependence on material, spot-size, pulse duration and wavelength than does the single pulse damage. In addition, more pulses are needed to produce macroscopic damage at a given intensity under irradiation at a 1 Hz pulse repetition rate than at 10 Hz. Possible mechanisms of the repetition rate dependence are briefly discussed.
Single-shot, Cummulative and PRF Dependent Laser Induced Damage Thresholds
Authors: Wood RM , Waite P , Sharma SK 
Published: December 2008

During the course of several laser damage programmes at HRC evidence has been accumulated on the different mechanisms and morphology of damage. This evidence has been gained at both 1.06 and 10.6 μm during single-shot, cummulative and prf testing of laser components.
This paper discusses, with both quantitative and photographic data the significance of (1) variation of the damage threshold values gained as a function of laser spot size and laser beam power and energy characteristics, and (2) the size and morphology of the damage spot gained under single shot, multiple and cummulative irradiation at prf's up to 100 Hz. Results are presented on Ge, ZnSe, ZnS, GaAs, CdTe, NaCl, KCl substrates and coated components at 10.6 μm and PMMA, fused silicon, Nd:laser glass and coated components at 1.06 μm.
Recent Damage Results for Antireflection Coatings at 355 nm
Authors: Hart TT , Carniglia CK , Rainer F , Staggs MC 
Published: December 2008

High-index and low-index thin-film antireflection (AR) coatings for use at 355 nm have been tested to determine their resistance to laser damage. All coatings consisted of dielectric materials which were vacuum deposited onto bowl-feed polished Suprasil II by evaporation. Laser damage studies were made by irradiating several sites on each sample with a 0.6 ns, 355 nm laser pulse. Each site was irradiated by only one pulse.
High-index coatings were made with both a high-index material and a low-index material. The high-index materials chosen for this study were scandia (Sc2O3), hafnia (HfO2), and zirconia (ZrO2), while the low-index materials were silica (SiO2) and magnesium fluoride (MgF2). All coatings had four non-quarterwave thick layers plus a halfwave-thick undercoat (barrier layer) of the low-index material. Average damage threshold values for four samples of each type ranged from 2.4 J/sq. cm to 3.1 J/sq. cm. Coatings made from scandia/magnesium fluoride had the highest damage thresholds.
Low-index coatings contained only low-index materials. The low-index materials chosen for this study were samarium fluoride (SmF3), lanthanum fluoride (LaF3) thorium fluoride (ThF4), silica, magnesium fluoride, and lithium fluoride (LiF). AR coatings containing three to six quarterwave-thick layers plus a halfwave-thick barrier layer were made from nine combinations of these six materials. Average damage threshold values for four to six samples of each type ranged from &lt; 1.0 J/sq. cm to 2.8 J/sq. cm. Coatings made from samarium fluoride/magnesium fluoride had the highest damage thresholds.
One set of four scandia/silica coatings was measured at both 355 nm and 248 nm. Damage thresholds at 248 nm for these parts were determined using 20 ns laser pulses. The average threshold was 4.2 J/sq. cm.
ASTM Safety Alert System
Authors: Oechsle SJ 
Published: December 2008

The ASTM Safety Alert System defines a system for alerting employees on a multiemployer construction site to the degree of hazard in the area where organic or inorganic solvented and/or reactive materials are being applied. The hazards are broken down into three categories: health, flammability, and reactivity. Each hazard is quantified on a scale from zero to four or none to severe. A placard has been developed with an adhesive back that can be posted at the entry to the work area. The placard will show the rating in each category and also the personal safety equipment required to enter the work area safely.
The package that will be available from ASTM will include a quantity of placards, a quantity of posters explaining the layout and use of the system, and a series of stickers indicating the various combinations of personal safety equipment that would be required under various conditions.
Fracture Toughness and Impact Characteristics of a Hybrid System: Glass-Fiber/Sand/Polyester
Authors: Joneja SK , Newaz GM 
Published: December 2008

In order to understand the damage mechanism in a glass-fiber/sand/polyester hybrid composite, it is essential to study the effects of inherent flaws or defects on the damage growth in the material. The irregular shape and presence of sharp geometric corners in the sand particles, voids, and improper interfacial bonding are factors that contribute to the weakening of the composite performance. One of the parameters influencing the defect formation is size of sand particles.
In this investigation, the thickness of glass/polyester layer is varied, while the sand/polyester layer is kept at a constant thickness. Laminates are made using different sand particle dimensions in order to investigate their influence on the performance of the hybrid composite. The combined effect of the defects is quantified by measuring the residual backing toughness provided by the glass/polyester layer after the full crack growth in the sand layer. The laminates having fine-sand particles provide better toughness properties in comparison to the coarse-sand laminates.
Impact studies are performed to evaluate the influence of defects on the hybrid composite behavior when subjected to impulsive loading. The load is applied to the glass/polyester face. The effect of thickness of the glass/polyester layer on damage initiation and propagation due to the impacting tup has been studied. It has been found that the thickness of the glass/polyester layer has a predominant influence on damage growth and mode of failure.
Characterization and Analysis of Damage Mechanisms in Tension-Tension Fatigue of Graphite/Epoxy Laminates
Authors: Jamison RD , Schulte K , Reifsnider KL , Stinchcomb WW 
Published: December 2008

The mechanisms by which subcritical and critical damage develops in several lamination geometries of T300/5208 and T300/914C graphite/epoxy material during tension-tension fatigue were closely examined. A damage analogue in the form of stiffness reduction was used to provide a framework by which the sequence of damage development could be correlated with mechanical response. Stiffness reduction, measured continuously during the course of cyclic loading, was shown to provide a reproducible characteristic correlation with percent of life expended. The relationship was observed to differ markedly among lamination geometries, but for a given geometry was found to clearly indicate the partition of the mechanical response into distinct regions in these characteristic curves. These regions, moreover, were shown to be predominated by particular damage mechanisms—some already discussed in the literature, others less well-recognized.
Results of the observed damage development sequence for cross-ply and quasi-isotropic laminates are presented along with a preliminary association between this damage and the characteristic stiffness reduction curves for these geometries. The geometries used were characterized by distinct, predominant, early subcritical damage conditions. This secondary and subsequent damage development was examined in relation to known, predictable beginning state. Of particular emphasis in each case was the role of this developing damage state in the fracture of fibers in the 0-deg plies.
Damage detection and characterization was accomplished using both nondestructive and microscopic techniques. Two techniques proved to be of considerable utility: penetrant-enhanced stereo X-ray radiography and scanning electron microscopy of coupons taken from penetrant-enhanced deplied, damaged specimens.
A number of significant damage conditions, not heretofore reported, were observed: the production of interior delaminations at the 0/90-deg interfaces of [0,902]s laminates by the gradual growth of longitudinal cracks in the 0-deg plies; the existence of a dense distributed microcrack condition at all distinct interfaces of [0,90,±45]s laminates; the segregation of 0-deg fiber breaks in all laminates into zones coincidental with cracks in the adjacent plies; and, the appearance of shear fracture in 0-deg fibers associated with the passage of longitudinal splits.
Mechanisms for each of these damage conditions are proposed in terms of the micromechanics of the predominant damage condition with which they are associated and the global stress state.
A Micromechanical Fracture Mechanics Analysis of a Fiber Composite Laminate Containing a Defect
Authors: Papaspyropoulos V , Ahmad J , Kanninen MF 
Published: December 2008

The vast majority of developments in fracture mechanics have been instigated by the need to avoid fracture of metals. Consequently, these developments are based on the assumption that the material is homogeneous—an assumption that is far more palatable in the case of most metals than it is for fiber-reinforced composites. Attempts to make fracture mechanics concepts more applicable to composite materials have resulted in the emergence of anisotropic fracture mechanics approaches. But, while this simple extension of linear elastic fracture mechanics does remove the assumption of material isotropy, it still assumes the material to be homogeneous. Experimental evidence suggests that the application of anisotropic fracture mechanics to fiber-reinforced composites still leads to inconsistencies in the prediction of fracture.
This paper presents an improvement in the application of a concept that allows for direct consideration of heterogeneous material behavior in the near crack tip region. The concept is similar to the singular perturbation and matched asymptotic expansion techniques used in fluid mechanics. The problem of a fiber-reinforced composite containing a flaw is divided into a local heterogeneous region (LHR) and a global anisotropic homogeneous continuum region. In the LHR, local failure events can be individually modeled, and then related to a global fracture parameter. Specifically, a quasi-three-dimensional finite-element LHR model is used to investigate micromechanical failure events at the tip of a crack in a fiber-reinforced composite laminate. These events are then related to a global fracture event, whereupon the fracture toughness of the composite can be estimated. Computational results, although in seemingly reasonable agreement with existing experimental data, are heuristic in nature. The work represents only a preliminary effort toward possible future development of a more sophisticated predictive model.