bluuebunny/crossref_metadata_2025_split huggingface dataset:
A simulation model of railroad reliability
Authors: Kesling G.D. , Whittaker I.C. 
Published: March 2007

A simulation model is used to study the relative reliability of struc tures subject to failure caused by fatigue cracking. This general model can be applied to most structures maintained by periodic inspections, including airplanes, bridges, pressure vessels, and nuclear reactors. The models of initiation and growth of cracks and the resulting fractures use a grid of stress cells to approx imate the cross-sectional shape of the structural components. Included in the analysis is a general model of the probabilitistic detection of cracks during an inspection. The reliabiltiy of struc tural components can be combined in the analysis to obtain overall structural reliability. The model was applied to railroad rails as a subcontract for the Department of Transportation. 29 Measurements of the rail's material characteristics and operating environment are used to estimate its reliability for a specified inspection schedule. The crack growth model selected for the rail application performs well for steel compositions, though alternative growth models are recommended for other materials. For the rail application, a model for computing the stress exposure of railroad rails is also included. Results from the rail application and use of these results to improve efficiency of resource allocations are presented.
ESL - A new Continuous System Simulation Language
Authors: Crosbie R.E. , Javey S. , Hay J.L. , Pearce J.G. 
Published: March 2007

ESL is a new Continuous System Simulation Language (CSSL) which is being developed under contract from the European Space Agency. It is based on the concepts outlined in Refer ence 6. The main features of the new language are: (1) Models can be built from submodels (2) Separation of model and experiment (3) Advanced discontinuity-handling (4) A parallel segment feature. The implementation of ESL requires both an interpreter and a translator version of the language. The interpreter translates the user's program into an intermediate code (H-code) which is then interpreted at run-time. The translator may be used to convert the H-code to FORTRAN-77 to produce a more efficient ex ecutable program of production runs. The entire system (with the exception of a few low-level routines) is being written in FORTRAN-77. A prototype version of the language was installed in August 1983 and is currently undergoing evaluations. Details of this version are given with examples of its use.
Linear systems revisited
Authors: Conley William 
Published: March 2007

An elegant and well-developed theory exists for solving systems of linear equations. It has been applied successfully for decades in industrial and scientific applications and it forms the basis for linear programming. However many systems of linear equations for industrial applications may require all of the variables to be nonnegative or in an even more restricted area, and/or to be whole numbers. These conditions can create difficulties for the standard approach. So presented here is a new absolute value transformation and a multi-stage Monte Carlo simulation solu tion technique for dealing with the nonnegativity solution re quirement and other conditions. The new approach has the ad ditional advantage of working on nonlinear problems. The system of equations is transformed into a statistic (where the minimum of the statistic is the solution of the system). Then solving the system of equations becomes a problem of finding a way across the sampling distribution to the minimum, which will solve the system of equations. Regular Monte Carlo simulation to solve a system or optimiza tion problem suffers from only being able to roughly approx imate the answer. Multi-stage Monte Carlo simulation overcomes this obstacle by using a more sophisticated sampling scheme and additionally exploiting the well-behaved nature of the sampling distributions of transformed systems of equations.
Project engineering and management for procurement of nuclear training simulators
Authors: Chou Q.B. , Payne C.A.J. , Davis R.M. , Acchione P.N. 
Published: March 2007

A comprehensive project engineering and management system has been developed and used by Ontario Hydro for the acquisi tion of nuclear generating station training simulators. This system was instrumental in the successful completion, on schedule and within budget, of the Bruce A and Pickering B Training Simulators and is presently being implemented on two other simulator projects. The developed engineering and management system includes some unique features such as a two-phased project, a project "core group" which actively monitors and controls the work, and joint buyer/vendor work procedures. Application of the project management system throughout the full simulator project cycle is described.
The probability distribution as a performance criterion when comparing alternative systems
Authors: Friedman Linda Weiser , Friedman Hershey H. 
Published: March 2007

The Kolmogorov-Smirnov test is used to determine whether the output distributions of two simulated systems are significantly different. The advantages of using this statistical procedure, and the danger in making comparisons between the systems with only the mean as a critical performance measure, are dem onstrated. Two queuing systems were simulated and results analyzed first by comparing means and, then, distributions. Results showed that, even if the means of two alternative systems are equivalent, the systems may still prove to be significantly different from each other if the entire distribution is examined.
The impact of advanced information processing on simulation — An illustrative review
Authors: Kerckhoffs E.J.H. , Vansteenkiste G.C. 
Published: March 2007

Advanced Information Processing (AIP) techniques are felt to play an important role in next generation simulation tools. Here we will review and illustrate the incorporation of two such AIP techniques in modelling and simulation. Simulation-oriented information-base management systems are considered to auto matize one of the major activities, peripheral to large-scale modelling and model implementation : the management of the descriptive and quantitative data involved. On the other hand, attention is paid to the impact of artificial intelligence techniques in modelling and simulation. Knowledge-based simulation, Al supported model synthesis and some additional topics with respect to integrating Al and the system analysis approach are briefly reviewed. Some concepts are illustrated on the basis of research activities in the Benelux countries.
Strategy-related characteristics of discrete-event languages and models
Authors: Hooper James W. 
Published: March 2007

In regard to available features, discrete-event simulation languages differ in many respects. There is, however, one aspect of a simula tion language that transcends all others in significance - namely, the strategy (or strategies) employed for "next event" selection. Strategy determines how a modeler must view a system which is to be modeled (i.e., determines the "world view"). The three generally recognized strategies are event scheduling, activity scan ning, and process interaction. Modern simulation languages may include combinations of these strategies. Analyses of the three strategies have been made, including the development of algorithms for each of the three strategies, and the use of the algorithms for in-depth comparisons of the char acteristics of languages employing each strategy. Models using different strategies have been compared relative to their develop ment characteristics and performance characteristics. Journal and conference Proceedings' articles spanning many years have been reviewed to obtain observations of simulation experts concern ing the impact of strategy on simulation languages and models. It is hoped that the perspective of strategies afforded by this discussion can lead to better-informed choices and more effec tive use of modeling tools and methods.
A simulation model for analyzing service times in a rotational position sensing disk system
Authors: Herring Bruce E. , Prather Wanda 
Published: March 2007

The performance of a computer system is often directly depen dent on the performance of the disk subsystems supporting it. Therefore, we have developed a model to aid in the evaluation of disk subsystem performance, with special emphasis on the rotational position sensing (RPS) feature due to its widespread use. The model produces I/O service times broken down by device within the disk subsystem, which can be used as a basis for design and placement decisions for critical applications. The model also produces channel and device utilizations and other measures of disk performance. Data-driven, the model uses data obtained from direct measure ment of the operating system in use. Thus the analyst need not know or make assumptions about the characteristics of the existing devices in the subsystem. Validation is accomplished through direct measurement of an existing system. In a wide-range of initial applications, the model has proven to be a valuable tool for the analysis of disk subsystems.
A network simulation model of a fish processing facility
Authors: Jonatansson Elias , Randhawa Sabah U. 
Published: March 2007

Quick-freezing, the single, most important production method in the fish processing industry, involves a number of production workstations. The mathematical analysis of such a system not only involves the process flow but also includes such factors as scheduling priorities, machine failures, and types of inputs and outputs. The resulting mathematical analysis is extremely com plex to conduct and difficult to explain to the production managers. A network-based simulation model is developed to analyze a fish processing facility, and the quick-freezing process in a typical fish processing plant is described. The network simulation model is then developed using the Simulation Language for Alternative Modeling (SLAM). Among the results from the model are statistics on utilization of machines and workers in the process, size of in-process inventory at different locations in the process, and throughput times. Sensitivity analysis is performed on some of the major factors that can affect the efficiency of the system. A front-end interface to the simulation model is developed which facilitates the user in entering input parameters to the model without the need to learn the simulation language. The model provides a methodology for evaluating alternative production strategies for a fish processing facility, and provides the production manager with a tool to develop short-term production policies.
The Surface of Cotton Fibers
Authors: Tripp Verne W. , Moore Anna T. , Rollins Mary L. 
Published: March 2007

The topography of unmoditied cotton fibers has been examined microscopically by means of surface replica techniques. The outstanding characteristic of the surface is a system of roughly parallel ridges and grooves spiraling around the fiber at an acute angle (usually 20 30 ) to its axis. The pattern of the surface is a reflection of the spiral fibrillar structure of the cellulose beneath the primary wall of the fiber. The average height and distance between ridges is approximately 0.5 micron. and many of the ridges are 10 or more microns in length. The surfaces of most native cottons are quite similar, although statistically significant differences in the average distance between ridges were found between certain samples The surface of fibers from unopened bolls is relatively smooth, but assumes the roughness of the typical fiber on drying for the first time. A characteristic surface formation ap peared to be associated with fibers known to have undergone compression. Drastic abrasion largely obliterates the normal appearance of the fiber surface.
Microscopic Studies on the Structure and Composition of Keratin Fibers1
Authors: Menkart J. , Coe A.B. 
Published: March 2007

The distribution of cystine sulfur in the cortex of various animal fibers has been investigated by the staining of cross sections with mercury vapor. The receptivity to dyes of various portions of the cortex has been found to be inversely related to their sulfur content. After oxidation with peracetic acid or bromine, the cystine-rich portion of the cortex in bilateral fibers (the paracortex) swells more in aqueous solutions than the orthocortex. Fibers so oxidized swell greatly in dilute, neutral or alkaline, solutions of strong electrolytes; the swelling is repressed at higher salt concentrations.
Thermal Comfort of Clothing of Varying Fiber Content
Authors: Werden Jane E. , Fahnestock M.K. , Galbraith Ruth L. 
Published: March 2007

This paper reports the results of thermal comfort studies on women subjects wearing complete outfits of clothing made from fabrics of cotton, nylon, acetate, and Arnel. The conditions of temperature and humidity were controlled to create environments ranging from slightly cool to hot. Total weight loss, evaporative weight loss, weight gain of clothing, rectal temperature, time of onset of sweating, and skin temperature were the objective measures used. A subjective comfort vote was also taken. By use of these measures, no significant differences were found among the fiber types in relation to thermal comfort of clothing. At 94° F. and 80% relative humidity the percentages of gain in clothing weight because of perspiration absorption were related to the original weights of the clothing assemblies rather than the characteristic moisture regain levels of the natural versus the man-made fibers. Environmental temperatures of 88° and 94° F. and relative humidity of 80% had decided effects on the comfort vote and total weight losses of the subjects. Evaporative weight loss was affected by relative humidity at all temperatures used in this study.
Supercontraction of Wool in Aqueous LiBr; In hibition by Free Br2 and its Relation to Sulfhydryl- Disulfide Interchange
Authors: Crewther W.G. , Dowling L.M. 
Published: March 2007

Wool treated with N-ethylmaleimicle (NEMI) to decrease the sulfhydryl content by 70% supercontracts much more slowly than untreated wool at 98.5° C. in 6 M LiBr at pH 6, whereas in 4 M LiBr/l N HCl the contraction rates of treated and untreated fibers are equal. Pretreatment of wool with dilute bisulfite solutions accelerates supercontrac tion much more in 4 M LiBr at pH 8 than in 4 M LiBr/1 N HCl. It is concluded that interchange reactions between sulfhydryl and disulfide groups facilitates supercontraction. The presence of Br2 in the solutions of LiBr used for supercontracting wool fibers causes different effects according to the pH of the LiBr solutions. In 1 N HCl the 118 supercontraction is accelerated at all levels of contraction; at pH 4 to 5 the initial stage of supercontraction is accelerated and the second stage of contraction retarded; at pH > 6 supercontraction is retarded at all levels of contraction. Wool fibers super- contract in solutions of Br2 in dilute HCl even at low temperatures. Evidence is presented that Br2 reacts with sulfhydryl groups of wool during super contraction in solutions of LiBr and that it acts at a site in the wool fibers affected by pretreatment with NEMI. Wool fibers which have been reduced with thioglycollate and either cross-linked with ethylene dibromide or reacted with methyl iodide show no change in contraction kinetics when Br2 is added to the LiBr solutions. It is concluded that Br2 inhibits supercontraction in solutions of LiBr by reacting with sulfhydryl groups and so interfering with interchange reactions between sulfhydryl and disulfide groups in the wool.
Rate of Felting of Untreated and Shrink-Resistant Wool Fabrics
Authors: McPhee J.R. 
Published: March 2007

Shrinkage-time curves for a range of wool fabrics, and the effect of various shrink- proofing treatments on these curves, have been studied. Felting rates of untreated fabrics depend on fabric structure and applied force in the way previously established [e.g., 3, 13, 15]. The shrinkage-time curves of treated fabrics show two definite stages, an initial portion indicating a very low felting rate, followed by a second stage where felting may be much more rapid. For a given fabric structure and given applied force, the felting rates of both stages, and the times at which the second stage begins, depend on the degree of treatment. The two-stage curves indicate two distinct steps in the felting of the fabrics and are not due to the fibers being unevenly treated. Frictional properties of treated Merino 64's fibers show no correlation with shrink resistance, and the results are qualitatively different from those found with Lincoln 36's. The importance of defining washing conditions when testing shrink-resistant wool fabrics is again emphasized by results showing that quite different impressions can be gained by washing in different machines and thereby applying different mechanical forces to the fabrics. In an extreme case, a treated fabric of loose structure, when washed for a given time in two different machines, can appear to be either completely shrinkproofed or scarcely shrink-resistant at all.
Kinetic Studies of the Wool -Water System
Authors: Watt I.C. , Algie J.E. 
Published: March 2007

Kinetic studies of the sorption of water, following a change of water vapor pressure surrounding wool fibers and horsehair with a high initial or final water content, are described. The processes of absorption and desorption show non-Fickian behavior over the entire course of water content change. An additional non-Fickian anomaly, present for both integral and interval absorption, is an overshoot above the final equilibrium con centration of water in the fibers. It is apparent that the initial molecular configuration of the keratin has a marked influence on the sorption behavior. The effect is greater at the high relative humidities of the experiments reported in this paper than at intermediate relative humidities (approximately 50% RH) as reported in Part II. Data obtained by a vibroscope technique show a different course of absorption, for the same changes of relative humidity around the fiber, than is found for the samples on the sorption balance. The non-Fickian nature of the process is evident in both techniques.
The Statistical Interpretation of Fiber Counts in Yarn Cross-Sections
Authors: Cooper D.N.E. 
Published: March 2007

Part I. In a model yarn spun from two components differing only in color. the factors affecting yarn irregularity may be divided into two classes, only one of which affects the regularity of blend proportions. The published tests for random mixing are reviewed and it is shown that the correct test for randomness is one based on the variance of blend proportions. Part II. When tests based on the theory of blending are applied to blends of dissimi lar fibers, the results must be interpreted with caution. Departures from randomness may be safely detected, but these departures may be caused by the physical differences between the fibers rather than by insufficient processing. Part III. The mixing of components within the cross-section must be considered separately, and special attention should be paid to effects in the yarn surface. The number of apparent groups along an arbitrary line in the section provides the most sensi tive test for departures from randomness, but information about the behavior of the individual components must be obtained by other means.
Fabric Construction for Wash-and-Wear Cottons
Authors: Krasny John F. , Sookne Arnold M. , Stam Paul B. 
Published: March 2007

Fabrics varying widely in fiber parameters and in yarn and fabric construction were treated with wash-and-wear resin formulations. Wash-and-wear ratings after tumble drying, crease recovery values, and breaking and tear strengths were determined. It was found that the wash-and-wear ratings of cotton fabrics after tumble drying were not systematically affected by the fabric construction, except that light, open-weave fabrics performed poorly. The crease recovery of resin-treated cotton fabrics was also relatively insensitive to construction. Both of these properties could, of course, be im proved by increasing the resin concentration. As a consequence of the relative insensitivity of wash-and-wear appearance ratings and crease recovery to construction variables, the principal emphasis in the design of functional wash-and-wear fabrics should be placed on gaining maximum strength. The breaking strength, at any one resin concentration, was found to be essentially linearly related to the weight of the fibers in the stressed yarn system, with the fiber strength ( Pressley, 5 mm between jaws) the only important secondary effect. The tear strength, too, was related in a gross manner to the fiber weight in the torn yarn system; it was, however, also improved by increasing the openness of the fabrics, by reducing the number of yarns per inch, by use of more open weaves, or by assembly of the fibers into fewer, coarser yarns rather than more numerous, finer yarns. The reduction of tear strength for a given improvement in wash-and-wear rating due to increased resin concentration seemed to be greater in fabrics woven from finer than those woven from coarser yarns and, in some cases, in open weaves as compared to plain weave fabrics. Quite generally, effects of fabric construction on crease recovery and strength observed in the untreated fabrics were reduced to various degrees by resin treatment.
Moisture Transfer in Textile Systems, Part I
Authors: Woodcock A.H. 
Published: March 2007

From theoretical considerations a new clothing parameter, the moisture permeability index, has been developed, which describes the efficiency of fabrics or fabric systems in transferring moisture and its associated latent heat. This index extends the existing "clo" formula, which related dry or nonsweating heat loss to clothing insulation and ambient temperature, to include the heat losses from sweat evaporation. Using this index, it is possible to predict the environmental range over which man may maintain thermal balance with a given heat production or, alternatively, the range of activity and associated heat dissipation for any given environment. It thus supplies not only the missing parameter for quantitatively describing the effect of clothing in hot weather but also permits the same theory to be applied in hot, temperature, or cold environments. The experimental method of determining this index is outlined, and typical results are given.
Gamma Ray-Induced Graft Copolymerization of Styrene onto Bleached Jute Yarn
Authors: Majumdar S.K. , Rapson W.H. 
Published: March 2007

When styrene was heated at 60° C in the presence of bleached jute containing 80% water, the rate of homopolymerization increased a little compared with that in the absence of water or jute, but substantial grafting of polystyrene onto the jute occurred. When water was not added to jute, the percent grafting was very small. With increasing amount of added water, grafting increased gradually to a maximum at 80-100% water on jute and then fell off somewhat with more water. This is assumed to be due to the formation of a barrier by water to the diffusion of styrene into the jute Pre-irradiation of bleached jute containing 80% water with increasing doses of gamma radiation decreased the amount of grafting on subsequent heating at 60° and 80°C. This phenomenon is peculiar to cellulosic materials containing some amount of lignin. When bleached jute containing 80% water and the styrene were separately pre- irradiated and subsequently heated together, grafting onto bleached jute increased steadily with time and was greater than in cases where the components were not pre-irradiated or only the bleached jute was pre-irradiated. when only the styrene was pre-irradiated. thermal grafting was very great even greater than that in simultaneous grafting.