bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulating carbon accumulation in northern ecosystems
Authors: Miller Philip C. , Kendall Richard , Oechel Walter C.
Published: March 2007

A model of the carbon balance in arctic and boreal forests has been developed to estimate the effects of higher carbon diox ide levels in the atmosphere on northern ecosystems. The model predicts that northern ecosystems should accumulate 5-10% of the carbon added to the atmosphere each year. Ac cumulation rates should increase by 2-8 times by year 2020 depending on the availability of nutrients. The rates of change in several processes are only estimates. The predictions are subject to large errors because of the complexity of ecosys tems interactions and the absence of data on the long-term ef fects of higher temperature and atmospheric CO2 levels. More differentiation of plant types, more feedback interactions, and more stochastic variations could improve the model. How ever, the results show that carbon accumulation in northern ecosystems is a significant fraction of the terrestrial carbon flux. The response of these systems is therefore important in predicting global carbon balance.
Using SLAM and SDL to assess space shuttle experiments
Authors: Standridge Charles R.
Published: March 2007

New tools simplify the development and simulation of models as well as the analysis and presentation of simulation results. The SLAM language allows the modeler to use network, dis crete event and continuous modeling prospectives in any combination to describe the different parts of a system. The SDL database management system allows the modeler to col lect simulation results, and at the same time to analyze and present these results independent of the simulation run.

We applied SLAM and SDL in analyzing a package of experi ments for the Space Shuttle. The SLAM model of the experi mental package shows the utility of a combined network, discrete event, and continuous model. The SDL database illustrates the advantages of storing model run results, using the computer in comparing alternatives, defining and comput ing performance measures after simulation results are made, and generating reports and plots of model results in the data base.

The results of our analysis were also of interest. Only a limited amount shuttle resources could be used by the package of ex periments. Thus, the simulation was used to determine the amount of memory needed for each experiment and for the microprocessor, as well as the reasons for the transmission delay for data from each experiment.
MANAGE - An interactive simulation model for evaluating the effects of management structure on organization performance
Authors: Sherman Michael D.
Published: March 2007

This research reports on progress to date in developing a com puterized simulation-optimization model of the general man agement structure of a firm. This model, called MANAGE, of fers a framework wherein the profit performance of a company can be simulated and assessed under a variety of structural con figurations. MANAGE also incorporates certain behavioral parameters that impact upon successful communication within corporate organizations. The paper describes the general framework of the model; the manner in which various struc tural, behavioral, and economic variables are incorporated into the model or can be set as desired by the user; and the nature of the outputs that are produced. Also described is the man ner in which MANAGE generates profit solutions under various combinations of behavioral, hierarchical, and economic con ditions and compares them with traditional optimal economic results. The paper concludes with a brief discussion of the potential applications of MANAGE.
Another method for random number generation on microcomputers
Authors: Jennergren L. Peter
Published: March 2007

The random number generator u(t + 1) = u(t) 513 mod 235 is suitable for simulation work on microcomputers. Results of statistical tests of this generator show that it has reasonable properties. It can easily be implemented either in PASCAL or in assembly language.
The use of simulation techniques in dynamic input-output modeling
Authors: Johnson Thomas G.
Published: March 2007

This paper describes a combined continuous-discrete simula tion model of an economy. The simulation model "solves" a dynamic input-output model (a system of differential equations) by numerically tracing the level of state variables through time. An analytic solution to this system, while possible, is imprac tical because of discontinuities in the state equations due to in dustry capacity constraints and irreversibilities in investment levels. The model is fitted with data for the Grant County Oregon economy and used to measure the dynamic impacts of an in crease in allowable timber harvest in the county. This study dem onstrates the advantages of the dynamic model over its static counterpart and explores its potential application to various economic impact problems.
Modeling with imperfect data: A case study simulating a biological system
Authors: Taha Hamdy A. , Stephen F.M.
Published: March 2007

This paper deals with a real-life application of simulation model ing to a biological system. A major obstacle, in the implemen tation of the otherwise well-defined model, is the difficulty of gathering some of the pertinent data. Unlike most familiar simulation models for which the system's design parameters are either available or can be estimated from available data, the nature of the system under study exists in an environment that makes it almost impossible to gather desired data. The paper proposes an "input-output" procedure that can be used to estimate the desired design parameters by indirectly using ac tual Input and output data of the system. A sample testing of the developed model based on the estimates obtained from the proposed procedure is also presented. The paper also points to the difficulties that typically exist in simulating many agricultural and biological systems.
The DISS methodology of distributed system simulation
Authors: Melman Myron , Livny Miron
Published: March 2007

The growing activity in the area of complex distributed systems has introduced the need for simulation aids that can enhance the generation of predicted performance data for such systems. A simulation modeling and programming methodology address ing itself to fully distributed processing systems and based upon the process concept of SIMSCRIPT II.5 is presented here. The language is based upon the principles of loosely coupled nodes displaying a cooperative autonomy in their internodal relation ship. The two levels of modularity used offers flexibility and ex tensibility of the models. A modeling procedure and complete example are presented.
The simulation of inventory systems: An overview
Authors: Banks Jerry , Malavé César O.
Published: March 2007

A survey of simulation techniques used in the modeling of in ventory systems was conducted. Six categories of use were formed. Research published in each of the categories was described. Observations were drawn in cases where research was sparse or where researchers seemed to have treated an er ror improperly.
ISIM - A simulation language for microprocessors
Authors: Hay John L. , Crosbie Roy E.
Published: March 2007

ISIM is a new simulation language for both 8- and 16-bit micro computers. It is derived from the interactive simulation language ISIS, which has been installed on a variety of minicomputers and mainframes over the past few years. ISIM can run on a small 8-bit microcomputer with the CP/M operating system, 48K bytes of memory and floppy discs. It also runs on the larger 16-bit com puters operating under CP/M 86 or MS-DOS, and on the IBM PC operating under PC-DOS. Its interactive graphics capability is best exploited using a graphics terminal or the microcomputer's integral graphics display (e.g., IBM PC Graphics Adapter). The language features interactive 'command' and 'program' modes and incorporates a simple editor and a file handling facility which is fully compatible with the operating system. ISIM provides a comprehensive, highly interactive, simulation environment which allows the user full control of the simulation. These features allow the simulation to be interrupted to enable the user to display or modify values of all user variables, change in tegration control variables, or perform post-mortem plots before proceeding with the execution of the run.
Crisis modeling of the criminal justice system
Authors: Legasto Augusto , Muriel Amador , Norman Morton
Published: March 2007

A crisis triggered procedure is applied to analysis of the criminal justice system of the United States; in particular, the develop ment of a "crisis triggered" computer simulation model of the criminal justice system is reported. The model is then used to identify potential major crises that have occurred or are ex pected to occur in the criminal justice system, to simulate them, and to study alternative regimes or patterns of recovery that the system may undergo.
A time-varying Poisson arrival process generator
Authors: Klein Robert W. , Roberts Stephen D.
Published: March 2007

Frequently an arrival process is acceptably Poisson, but the ar rival rate varies with time. This note uses inversion to derive a time-varying Poisson generator whose rate function is continuous and piecewise-linear. The piecewise-linear function includes the piecewise constant arrival rate while involving only slightly more computations and represents a reasonable compromise between flexibility and practicality. In this case, inversion is efficient while being highly compatible with correlation induction variance reduction methods. The generator has been implemented for routine use in the INSIGHT simulation language providing a useful new input process while promoting variance reduction through common and antithetic variates.
Simulation of medical decisions: Applications of SLN
Authors: Roberts Stephen D. , Klein Robert W.
Published: March 2007

Simulation has been applied to several important medical deci sion problems using the SLN language. The applications to end- stage renal disease, chronic stable angina, renal artery stenosis, and treatment of hypertension and hypercholesterolemia are reviewed emphasizing the modeling considerations and results. These investigations support the utility of simulation in medical decisions and the applicability of SLN to these problems. The general applicability of simulation to medical decision problems must be evaluated in the context of available knowledge and data. The simulation of medical decisions does not produce dependence among observations so prevalent in discrete-event simulations, but to the extent that arbitrary criteria such as cost- effectiveness are estimated, statistical concerns remain. Simula tion, particularly with SLN, can play an important role in medical protocol design.
Digital simulation of polarimetric radars
Authors: Russell Robert F. , Sedenquist Fred W.
Published: March 2007

A new generation of radar systems that exploit the polarizing characteristics of various targets and clutter are under develop ment. These radars utilize the high-range resolution techniques of frequency-agile fast Fourier transform techniques and are a radical departure from conventional pulse radar. The methods of simulating these new processes and typical results are shown.
Modeling human operators on a microcomputer: A micro version of SAINT
Authors: Laughery K. Ronald
Published: March 2007

During the past decade, significant advances have been made in the tools available for human performance modeling. Primary advances have been in the development of languages aimed specifically at operator modeling; concurrently, microcomputer technology has been advancing rapidly. A language, which is conceptually similar to some other network modeling languages, was designed for human operator modeling on a microcomputer. Although this language is more limited in some respects; it is easier to use. The language's capabilities, limitations and opera tional tests of its efficiency are presented.
Optimization of the maintenance process
Authors: Czajkiewicz Zbigniew J.
Published: March 2007

A comprehensive preventive maintenance program minimizes equipment breakdowns and cuts operating costs, which in turn improves productivity.

A mathematical definition of the maintenance process and criteria for its optimization is presented in two stages: (1) struc tural optimization of a maintenance process by selecting an ap propriate repair strategy and (2) parametrical optimization con sisting of choosing optimal (based on assumed criterion) times and scopes of repair actions. General classification of the repair strategies, their characteristics and results of simulation ex periments are presented.
An efficient technique for minimum-cost tolerance assignment
Authors: Sayed Salah E. Y. , Kheir Naim A.
Published: March 2007

A computer-aided design technique to assign tolerances to system components is introduced. The essence of the method is to ac curately represent the allowable margins of the system's perfor mance functions in the percent deviation parameter space (PDPS) and to determine the point in the PDPS corresponding to the most efficient tolerance assignment. The criteria used in volve minimum cost-tolerance assignments.

The technique presented solves the tolerance assignment prob lem for a significant class of systems for which one hundred percent yield is sought and whose components are statistically independent. The most salient feature of this technique is the simple and straightforward manner in which the "curse of dimen sionality" associated with tolerance assignment problems is overcome.

A computer program has been developed; it accepts a system's topology, nominal component values, a figure-of-merit for system performance, and information relating a component cost to its tolerance. The output of the program includes the set of com ponent tolerances that will produce the least expensive design with a hundred percent yield. As an example, a rather complex low pass filter has been simulated to solve the tolerance assign ment problem. Computation time is about seven seconds on the Univac-1100 computer.
An Intel 2920 microcomputer-based stabilization controller
Authors: Anakwa Winfred K. N. , Swamy M.N.S.
Published: March 2007

An analog output feedback controller designed to stabilize an unstable third-order system is implemented on an Intel 2920 microcomputer. The unstable plant is simulated on an EAI 680 analog computer and the microcomputer is used as an observer in the feedback loop. The sampling interval depends on the length of the computer program and the speed of the micro processor. The performance of the system controlled by the In tel 2920 microcomputer is compared with the corresponding performance of the analog controlled system. Advantages and limitations of using the Intel 2920 microcomputer as a single chip controller are discussed.
Discrete-event simulation of agricultural pest management systems
Authors: Oddson John Keith , Aggarwal Sudhir
Published: March 2007

Discrete-event modelling and simulation strategies have been used successfully in many areas to simulate activities which can be viewed clearly as a succession of separate events. A discrete- event approach can also be appropriate for the study of many agricultural pest management systems. To demonstrate the general methodology, the following detailed description of a par ticular case was used - the computer implementation of a discrete-event model which simulates the population dynamics and damage potential of a navel orangeworm infestation in an almond orchard under the influence of ambient weather con ditions and a variety of grower management actions. The pro gram, written in (UCSD) Pascal, is completely encased in interac tive, shepherding software which allows the user considerable flexibility in the prescription of model parameters and in the in put of initial data, as well as in the selection of model output options. Use of this model as a pest management tool should provide a better qualitative and quantitative understanding of the life cycle and crop interactions of this pest and may lead to improved measures for its control. More generally, the pre sent paper can serve as a guide for the application of the discrete- event approach in the study of other pest management or ecological systems.
An example of error analysis in dynamic model validation
Authors: Damborg Mark J.
Published: March 2007

Determining the quality of a model is always troublesome for the model builder and/or user. Error analysis is a useful approach when modeling dynamic systems and when measurements or nominal trajectories are available from the physical system. Techniques of error analysis based upon measures of the error in both the time and frequency domains are discussed. Further, an approach to analyzing the propagation of errors based upon dynamic models of the error is presented. Time domain measures and error propagation analysis are demonstrated on a sixth-order river basin econometric model.
Formulated problem verification as an explicit requirement of model credibility
Authors: Balci Osman , Nance Richard E.
Published: March 2007

This paper deals with the formulation and formulation verifica tion of a class of problems to which "modeling solutions" are applied. Two main objectives are to develop a procedure for problem formulation and to propose indicators for the for mulated problem verification. The class of problems considered is analyzed in two categories as requiring prescriptive or descrip tive solutions. A detailed study of each category results in a pro cedure to guide the analyst during the problem formulation. This procedure is illustrated by a traffic intersection problem. The for mulated problem is measured by using indicators to accomplish an evalution for the formulated problem verification. Indicators are developed to measure (1) the probability of failing to solve the actual problem, (2) the acceptability of an alternative set of possible outcomes, and (3) how well the formulated problem is structured. An evaluation questionnaire, included in the Ap pendix, is employed in applying the proposed indicators.
A simulation of a multi-item drug inventory system
Authors: Ebrahimzadeh Magid , Barnoon Shlomo , Sinuani-Stern Zilla
Published: March 2007

A simulation model can be used for determining inventory order ing policy in a regional drug warehouse of Kupat—Holim — the largest provider of health services in Israel. This is a multi-item system with stochastic demand and lead time, periodical order ing, fixed ordering costs, and shortage and holding costs vary ing from drug to drug. Current ordering policy takes place monthly according to the subjective judgment of the regional chief pharmacist; this can lead to a high frequency of shortages. Two important points - to minimize the total costs and to decrease the probablities of shortages - were studied by this model. Two policies were considered:  where at each period T, a fixed quantity Qi of drug i is ordered; and  where at each period T the inventory level of each drug i, is reviewed if it is under r i an order is placed up to the level Ri. It was found that the  policy is preferred, the total cost is reduced significantly, and the probabilities of shortage for most drugs dropped to zero.
Performing simulation projects with The Extended Simulation System (TESS)
Authors: Standridge Charles R.
Published: March 2007

TESS, The Extended Simulation System, provides a comprehen sive, flexible and integrated framework for performing simula tion projects. Capabilities include (1) graphically building SLAM II networks and schematic models; (2) forms entry for simulation control information, simulation inputs, and anima tion specifications; (3) database management of user-defined data, model inputs and model outputs; (4) preparation of reports and graphs; (5) analysis of simulation results; and (6) the anima tion of simulation runs. A nonprocedural command language provides access to the graphical builders and forms system as well as selects data for reports, graphs, analysis or animation. In addition, a library of subroutines gives the programmer ac cess to all data in the TESS database.

The TESS project framework consists of nine elements of a proj ect and three functions for operating on these elements. Integra tion is based on a single, central database containing all element occurrences. A comprehensive example illustrates the problem- solving procedures possible with TESS.
Improving the assessment of power systems reliability through simulation
Authors: Blackstone John H. , Hogg Gary L. , Patton Alton D.
Published: March 2007

The major finding of this study is that accurate prediction of reliability indices for electric power systems1 requires modeling of several operating considerations not usually present in analytical models. The principal features are the actual cycling duty of generators, the modeling of start-up delays, and the ex plicit treatment of unplanned unit outage postponabilities. All of these factors proved to significantly impact reliability indepen dent of system configuration or demand for electric power. The model presented here models all these factors in a computa tionally efficient manner.
Simulation and expert systems- A taxonomy and some examples
Authors: O'Keefe Robert
Published: March 2007

Simulation and expert systems are remarkably similar. Both employ various representations to model some aspect of an uncertain world, with the model being formed as a piece of com puter software. This is then employed to aid decision making. Ideas about combining simulation and expert systems are presented, and a taxonomy is developed. It is concluded that the most fruitful areas of cross-fertilization are advice-giving ex pert systems that assist the simulation scientist and simulation user, new simulation tools built from knowledge-based tools, and intelligent front ends for simulation packages. Advice-giving systems will increasingly be part of simulation environments, rather than stand alone. They will be aimed primarily at the in experienced simulationist. An example of a system developed in this vein, which advises on experimentation with transaction flow models, is presented. Regarding the use of knowledge-based tools, induction as an aid to the development of a discrete model is considered.
SCS Activities: Help us close the loop
Authors: Marr George R.
Published: March 2007

SCS Activities are a new part of the Society, intended to bring growth and vitality to our organization. Activity vice presidents are new Society officers charged with insuring the development and effectiveness of Activities.

Activities are special interest groups — as simple as that, each one a group of people organized around an idea that is of importance to simulation and of interest to the So ciety membership.

The aim here is to describe existing and potential Activities and to solicit proposals for new ones.
Comparing simulated alternatives using a distribution-free statistic with blocking by random number stream
Authors: Friedman Linda Weiser , Friedman Hershey H.
Published: March 2007

When comparing system alternatives, simulationists will often use analysis of variance, a parametric statistical procedure. Using an example in which three different M/M/s queuing system con figurations are simulated, the authors demonstrate the impor tance of using the common random number streams as blocks. In addition, Friedman's Two-way Analysis of Variance by Ranks test, a distribution-free statistical procedure, is used to analyze the output.
Policy simulation in the natural resource sector
Authors: Vlahovich Vladimir , Perry Patrick F.
Published: March 2007

A simulation framework suitable for the quantitative assessment of policies in the natural resource sector is considered. It is based on a combination of conventional econometric methods with technical and engineering models which describe the input- output and environmental relationships of the natural resource sector. A detailed study of the effect of fiscal and monetary poli cies on the housing market and on the resource industries sup plying housing materials is considered for purpose of illustration, with particular emphasis on the wood (lumber and plywood) used in housing. A validated 30-equation simulation model has been constructed. This describes the housing market, materials used in housing, production functions for these materials, and environmental effects of this production activity. A sample policy simulation is given. The main contribution of the work has been the updating of an existing housing model and the development of its linkages with the lumber and plywood sector.
Simulation of coal preparation plants
Authors: Gottfried Byron S. , Tierney John W.
Published: March 2007

Coal preparation is a process for removing physical impurities from coal. The process is carried out in large plants whose capa cities range from 500 to 20,000 tons of coal per day. There are about 500 such plants within the United States.

A coal preparation plant simulator was developed under the sponsorship of the U.S. Department of Energy for simulating coal preparation plant performance. The simulator contains mathe matical models describing all the major components of an actual coal preparation plant. Moreover, it utilizes a network-type struc ture, thus permitting the simulator to be used for a wide variety of different plant configurations. Both the models and the net work structure are described in this paper. Results are shown for a sample problem, which is representative of an actual coal preparation plant configuration.
The contrasting roles of Monte Carlo simulation and gaming in decision support systems
Authors: Gray Paul , Borovits Israel
Published: March 2007

Fixed-time interval simulation has been used extensively in deci sion support systems to provide an understanding of the nature of the risks involved in proposed choices. An alternative ap proach, which is particularly suitable for decisions involving group concensus is the use of operational gaming. This paper describes these two approaches and compares their advantages and disadvantages. The concept of using decision rooms as gam ing environments for supporting group decision making is intro duced and explored.
Multi-echelon system design via simulation
Authors: Chrissis James W. , Gecan Anton S.
Published: March 2007

Our approach to determining the design parameters for a multi- echelon maintenance system is to achieve a minimum-cost ar chitecture that delivers a specified level of availability to the sup port system. Decision variables represent the amount of test equipment and the number of spares allocated to the various repair levels. Structured as an optimization problem, the system performance measure is obtained through simulation. A direct search technique is employed to iteratively seek an indicated optimal solution. An additional decision criterion is used to deter mine the run length at each search point and for indicating termination.
QUAL: A microcomputer system for qualitative simulation
Authors: Cochran Jeffery K. , Paul Brian K.
Published: March 2007

The field of qualitative simulation and reasoning is rapidly becoming a sought after means for modeling physical systems. However, much is yet to be explored within this field. The central feature of qualitative modeling is the use of qualitative variable descriptions and logic rules for manipulat ing variable values between systemic states. In this paper, the development and applica tion of a generic qualitative simulation environment named QUAL is provided. This environment assists the user in setting up a qualitative model, executing it, and forming a decision tree of the results. The use of qualitative reasoning in a microcom puter simulation context is presented and used to identify limitations of a purely qualitative modeling environment.
The Effect of Processing on Cotton Fiber Properties
Authors: Rebenfeld L.
Published: March 2007

In order to ascertain the effect of several processing steps on cotton uber mechanical properties, six cottons in one-bale quantities were manufactured under identical conditions into a standard construction sheeting Samples were removed at several processing stations including the original bale, the yarns, the scoured fabrics, the bleached and mercerized fabrics as well as resin-finished fabrics. The mechanical properties of fibers taken from these stages were determined and the effect of each processing step was examined. It was noted that cotton fiber properties are altered by processing and that the magnitude of the changegs in these properties is not constant for all cottons. In many cases the changes in fiber properties are functions of the original other properties. It was also shown that the changes in fiber properties are reflected in the changes of the fabric characteristics, thus indicating the validity of the premise that fiber properties influence the bahavior of cotton fabrics.
The Effects of Gamma Radiation on Cotton
Authors: Blouin Florine A. , Arthur Jett C.
Published: March 2007

Two series of samples of purified cotton were irradiated in oxygen and nitrogen atmospheres with gamma rays at six dosage levels ranging from 100.000 to 100.000.000 roentgens. Some of the chemical and physical properties of the irradiated cellulose were determined by means of various widely used techniques of cellulose chemistry. It was found that high energy gamma irradiation of cotton resulted in carbonyl group formation, carboxyl group formation, and chain cleavage in the approximate ratio of 20 : 1 : 1 ; increased solubility in water and in dilute alkali ; decrease in tensile strength of the fibers ; small but unusual changes in moisture regain: relatively unchanged infrared absorption spectra ; and the same type of degradation in a nitrogen atmosphere as in an oxygen atmosphere, with oxygen producing only slight enhancement of the reaction.
A Method for Measuring Yarn Softness and Its Use to Show the Effect of Single and Ply Twist on the Softness of 31/2 Cotton Yarns
Authors: Skau Evald L. , Honold Edith , Boudreau William A.
Published: March 2007

An apparatus is described for measuring yarn softness in terms of the percent increase in yarn width when the yarn is subjected to lateral pressure between two parallel plane surfaces. Softness data obtained on a family of 31/2 cotton yarns have been presented as a contour diagram which, in connection with similar contour diagrams of other important yarn properties, shows the interrelationship of these properties over a wide range of single and ply twist combinations.
Oil and Water Repellent Treatments for Cotton with Fluorochemicals1
Authors: Segal Leon , Philips F.J. , Loeb Leopold , Clayton R.L.
Published: March 2007

The application of some fluorochemicals to cotton textiles to impart oleophobic and hydrophobic surface characteristics to the materials has been investigated further.

The chromium complexes of perfluoromonocarboxylic acids were used in conjunction with acrylic emulsion. These were employed in separate operations as well as combined with the complexes into one emulsion. Pernuoromonocarboxytic acids were applied to fabrics after impregnation with a mordant to bond the acid to the fiber.

Data are presented to show the relative effectiveness of the repellency treatments as governed by the fabric construction.
Dialdehydes as Cotton Cellulose Cross-Linkers1
Authors: Hurwitz Melvin D. , Conlon Lawrence E.
Published: March 2007

Formaldehyde, when applied with acid catalysis, is the most effective cellulose cross linker available in that it produces the most crushproofing on a weight basis. However, formalization is accompanied by high strength loss in cotton.

It has been postulated that the unfavorable crease recovery-strength relationship with formaldehyde is a function of the shortness of the acetal cross-link. It has also been postulated, naively, that longer cross-links could be derived from long chain dialdehydes, the crease recovery-strength relationship improving with increasing chain length.

Work with the dialdehydes glyoxal (C2). glutaraldehyde (C5). and α-hydroxy adipaldehyde (C6) yielded crease recovery-strength relationships similar, if not identical. to formaldehyde. This tinding is consistent with the known chemistry of the formalde hyde-cellulose reaction in that the acetal linkage controls the length of the cross-link.
Applications of Infrared Absorption Spectroscopy to Investigations of Cotton and Modified Cottons
Authors: O'Connor Robert T. , DuPré Elsie F. , McCall Elizabeth R.
Published: March 2007

The potassium bromide disc technique is being used for rapid, simple, and reproducible measurement of the infrared spectra, of modified cotton fibers, yarns, and fabrics. Ap plications of the procedure have demonstrated that chemical modification can be readily detected and identified and that the extent of treatment can be quantitatively estimated. Experiments have been designed to select bands most useful in investigations of cotton modified by esterification. etherification, or replacement reactions. The examples cited illustrate the potential usefulness of infrared absorption spectra to studies in this field. A list has been prepared of 50 infrared absorption bands (and correlations with vibrating groups which give rise to them) which summarize the spectral characteristics which have been found most useful in investigations of cottons modified by esterification, etherifica tion, and replacement reactions.
Means for Measuring Neps Produced by Ginning Treatments1
Authors: Shepherd Jacob V.
Published: March 2007

A faster method of measuring neps in cotton ginned lint has been developed at the Cotton Ginning Research Laboratory, Stoneville, Mississippi.

The time saved by this method is due largely to the use of a lap maker and a modified definition of what constitutes a nep, and amounts to 50% of the AMS method currently used.

This method is used at the Stoneville Laboratory to make preliminary screening tests in the Ginning Research program.
An Investigation of Air Pressures in the Cotton Carding Machine1
Authors: Miller A.L. , Brown R.S. , Rusca R.A.
Published: March 2007

An investigation is reported of the air pressures in the conventional cotton card, measured at strategic points with the card running idle and when processing cotton. Through the utilization of a sensitive electronic instrument capable of measuring pressures of 0.001 in. of water, both static and velocity determinations were made that have given an insight into the function of air in the card and have led to the development of a method of carding without the use of the conventional revolving flats.
Procion Dye Staining for Differentiation of Skin and Core of Viscose Rayon Fibers
Authors: Kato Koichi
Published: March 2007

A new microscopical technique for differentiating the skin—core structure of viscose rayon fibers is described. Slide preparations mounting fiber cross sections are stained with an alkaline solution of Procion Black HGS, which is a Procion dye recently mar keted by ICI as a chemically reactive dye for cellulose fibers. This technique is found to furnish a staining entirely selective for the skin area in a simple and rapid way.

Since it is well established that Procion dyes do react chemically with cellulose mole cules under alkaline conditions, it is highly probable that the differential staining pro duced by the present technique is due to a definite difference existing between the skin and the core with respect to the chemical reactivity toward the dye employed. This differentiation mechanism appears to be quite different from that which is generally accepted to be the case in the previously described techniques using ordinary dyes.

Typical results are presented for several types of cellulose rayons showing various staining behaviors. It is seen that these results are in good agreement with those obtained by other stain methods.

The same procedure, when applied to a variety of fibers other than cellulosics, is found to give positive staining reactions only to wool, silk, regenerated protein, and Vinylon fibers. Although most of these findings are as yet not satisfactorily explained, reactive dye staining of this kind seems to be of much promise in the field of fiber micros copy.
The Change in Stress on Wetting and Drying Wool Fibers
Authors: Feughelman M.
Published: March 2007

When a wet wool fiber is strained to a fixed extension, allowed to remain at this exten sion for a time, and then dried, the stress in the fiber rises. This rise of stress is independ ent of the time as long as it is greater than about 1 min. and is also independent of a number of chemical and physical modifications to various fibers. The rise in stress is dependent on the strain and increases to a maximum value at about 30% strain. Be tween 30% and 50% strain no further increase was recorded. From the evidence presented, it is suggested that drying the fiber in a strained state introduces strained hydro gen bonds, which are responsible for the stress rise on drying.
The Dry Weight of Wool
Authors: Watt I.C. , Kennett R.H. , James J.F.P.
Published: March 2007

A study has been made of the drying of wool in vacuo. The time required to reach the equilibrium weight decreases with increasing temperature of drying, and the equilibrium weight decreases with increasing temperature up to 140° C. The equilibrium weight obtained in vacuo is less than the weight obtained in air under the same conditions. The absolute dry weight of a wool sample is defined as that weight obtained on heating the sample in vacuo to 140° C. for at least 10 min.

The activation energy of drying increased markedly at low regains. From compar ison with partially acetylated wool it was concluded that drying wool at low regains involves the removal of water from hydrophilic sites.
The Drying of a Mass of Hygroscopic Fibers by Forced Convection of Air: A Note on Some Physical Aspects
Authors: Downes J.G. , McMahon G.B.
Published: March 2007

It is pointed out that, in drying of a uniform mass of fibers by forced convective air flow through the mass, a "drying front" proceeds through the mass in the same direction as, but much more slowly than, the air flow. Therefore, if uniform drying is to be obtained, the process must continue until the front has emerged from the downstream face of the mass of fibers; air of appropriate relative humidity must be used to leave the fibers at the desired regain; and reversal of air flow direction is undesirable on grounds of efficiency.

Calculations have been made of the capacity of air to remove water from a mass of wool fibers, the mass being left at given values of regain (4, 8, 12, and 16%). It is found that, except for the case of 4% regain, the capacity for water removal depends very little on the initial temperature of the air (in the range 30°-110° C.).
The Plasticity of Wool
Authors: Whiteley K.J. , Speakman J.B.
Published: March 2007

The plasticity of wool increases, and the difference of plasticity between fibers from primary and secondary follicles is accentuated, as the level of nutrition of the sheep decreases.
New Developments in Epoxide Wash-Wear Finishes for Cotton
Authors: Galligan John , Sookne Arnold M. , Adams J.T. , Guest Howard , Lourigan George H.
Published: March 2007

A study has been made of a number of epoxides of potential and current utility for the treatment of cotton to produce crease recovery and wash-and-wear properties. The prop erties imparted to cotton by these products vary greatly with respect to the color of the fabric, the retention of strength for a given level of crease recovery, the rate of hydrolysis of the epoxide in the treating bath, etc. It is in fact unreasonable to consider all epoxides as a class. since they differ as much from one another as they do from the conventional nitrogen-containing finishes. In general, however, they demonstrate resistance to chlorine retention and a high level of durability to all types of laundering, including that used by commercial launclries.

One of the most promising epoxides examined was vinylcyclohexene dioxide, which imparted a desirable combination of properties to cotton when used alone or in 2: 1 blends with most commercially used nitrogenous resins.

Some treatments of cotton were performed with 1,1,3-tris-(2,3-epoxypropoxy)-hutane, This tri-epoxide contains an acid-labile acetal linkage, which can be readily hydrolyzed. The properties of cotton treated with this epoxide were examined before and after hy drolysis. and provided confirmatory evidence for the important role of cross-linking in improving the properties of cellulose with resin treatments.
Part II: Buckling
Authors: Dahlberg Bengt
Published: March 2007

In this part, a method for measuring plate and shell buckling of fabrics is described. The same instrument can also be used to measure extension-compression in the plane of the fabric. The instrument consists of an attachment to the Instron Tensile Tester, and complete load-deformation curves are obtained.
The Influence of Changes in Moisture Content on the Wrinkle Recovery of Fabrics, Part I
Authors: Farnworth A.J. , Lindberg Joel
Published: March 2007

A study has been made of the effect of rate of drying, and of alternate wetting and drying, on the wrinkle recovery of fabrics of wool, wool blends, and cotton, when wrinkled in the wet state.

Recovery is independent of the rate of drying, but a second-stage rapid recovery occurs at a stage in drying corresponding to loss of water from the internal fiber structure, as distinct from surface evaporation. Repeated, alternate increase and de crease of regain leads to progressive, step-wise recovery from wet wrinkling.

It is probable that the energy required to give these effects originates from the swelling-deswelling associated with changes in regain.
Lightfastness Studies of Basic Dyes on Acid- Modified "Dacron" 1 Polyester Fiber
Authors: Maerov S.B. , Kobsa H.
Published: March 2007

Application of basic dyes to acid-modified polyethylene terephthalate fibers offers such attractive features as brightness of shade, excellent color value, and good solvent and sublimation-fastness. Lightfastness studies of basic dyes on this polymeric substrate indicate that the Critical Fading Region (C.F.R.) is a rather narrow spectral region extending from 350 to 425 mμ. Substituted hydroxybenzophenones such as 2,2'-di hydroxy-4,4'-dimethoxybenzophenone (DHDMBP) act as light screeners with many of these dyes in the C.F.R. and extend their lightfastness in dyed fabrics. Many of these screeners can be applied to the fiber by normal dyeing techniques. The requirements for efficient screening ability of these agents are discussed. Photosensitization of dyes by some screeners with a resultant diminution of lightfastness is ascribed to a radiationless transfer of energy from screener to dye by a resonance transfer mechanism. Chemically modified DHDMBP gave improved lightfastness in dark shades utilizing the tinctorially strong triphenylmethane dyes. The lightfastness improvement due to these modifications can be ascribed to their enhanced bathochromic absorption in the C.F.R. relative to the absorption spectrum of DHDMBY.
Stress-Strain Relationships in Yarns Subjected to Rapid Impact Loading
Authors: Smith Jack C. , Shouse Paul J. , Blandford Josephine M. , Towne Kathryn M.
Published: March 2007

Stress-strain curves at rates of straining up to 440,000%/min. have been obtained for a number of textile yarns by a technique involving high-speed photography of the yarn following transverse impact. These curves and others obtained at conventional speeds are presented for samples of acetate, triacetate, cotton, polyester, glass fiber, human hair, vinal, nylon, acrylic, rayon, saran, and silk yarns. Also given are specific breaking energies obtained from the areas under the stress-strain curves and by direct measurements involving longitudinal impact speeds of the order of 50 m./sec. These data show how stress-strain curves depend upon rate of straining and provide ratings for the yarns with respect to ability to survive impact and to resist impact without appreciable deformation.
Wrinkle Resistant Properties of Dialdehyde Cotton
Authors: Mack Charles H. , Reeves Wilson A.
Published: March 2007

The effect of periodic acid oxidation on the wrinkle resistance of cotton fabric has been investigated. In the range of oxidation where basic fabric properties are pre served the dry WRA increases with increasing oxidation. The change in wet WRA for these fabrics is negligible, suggesting that cross-links which are evident in the dry state are broken in the presence of water. An explanation involving hémiacetal and hemialdal formation is advanced.
The Spectral Distribution of Sound Produced by Fibers and Fabrics in Friction
Authors: Thorsen Walter J. , Veneklasen Paul
Published: March 2007

The constructional details and theory of operation of a highly stable and sensitive fiber and fabric friction sound analyzer are described. Sound pressure curves for three typical fabrics and one bulk wool are shown. Results will be described in detail in Part II.
The Effect of the Short Fibers in a Cotton on Its Processing Efficiency and Product Quality
Authors: Tallant John D. , Fiori Louis A. , Alberson David M. , Chapman Walter E.
Published: March 2007

By differentially ginning a single lot of Acala 44 cotton, various short fiber content levels were obtained. Yarns produced from these cottons showed the effects of increases in short fiber content; namely, reduced strength, elongation, and appearance grade. The twist required for maximum strength was found to be largely unaffected by changes in short fiber content, except for a medium yarn number for which a relationship was demonstrated. A graph showing the close relationship between the percentage of fibers less than 3/8 in. and those less than 1/2 in., calculated for a wide number of cottons, is included. Spinning efficiency is shown to be adversely affected by changes in short fiber content.
Geometry and Properties of Cotton Two-Bar Raschel Fabrics
Authors: Fletcher Hazel M. , Roberts S. Helen
Published: March 2007

The relation of the geometry to the physical properties of 32 experimental raschel fabrics was studied. These fabrics were knit of 36/2 combed cotton yarns with the ordinary stitch, straight chaining, and lay-in in the following combinations: straight chaining with lay-in; ordinary with lay-in ; two-bar Atlas with skip entry; two-bar jersey with skip entry; straight chaining with ordinary; eyelet mesh with irregular entry. The effect of distortion on dimensional change in laundering, relaxation to remove distortion in order to prevent dimensional change, and the elastic behavior of the various construc tions were given special attention, since these properties largely determine the usefulness of the fabrics for specific purposes.
Cohesion Phenomena in Cotton Rovings and Yarns
Authors: Barella Alberto , Sust Antonio
Published: March 2007

In the present work, cohesion phenomena of a general character are studied in cotton rovings and yarns. The cohesion is expressed as a coefficient of minimum twist of cohesion, and the following are considered throughout the work: (a) influence of testing conditions on the cohesion of rovings and yarns, (b) influence of fiber characteristics on cohesion. Finally, on the basis of data of the cohesion test, the strength of cotton rovings is also considered. In this first part of the work, commercial yarns and rovings have been used.