bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Study of the Mechanism of Loop Formation on Weft-Knitting Machinery
Authors: Knapton James J. F. , Munden Dennis L. 
Published: March 2007

A detailed study was made of the effects of yarn friction on the magnitude of the tensions developed in the knitting zone of the standard weft-knitting machine and the in fluence of these tensions on loop formation and fabric quality. Variations in loop length of ±10% due to changes in yarn friction may be experienced at given cam settings and input tensions and these variations can be explained by the phenomenon of "robbing-back." A geometrical model of loop formation is suggested as a means of mathematically predicting the values of the developed tensions, and the position and magnitude of the maximum knitting tensions Tk within the knitting zone, knowing the coefficient of yarn friction μ. This analysis suggests that the knitted loop length depends on the position of Tk rather than on the magnitude of Tk, but that fabric holes and "press-offs" are caused by Tk exceeding the breaking load of the yarn. For high values of μ, Tk exceeds the breaking load more readily than for low values. It is predicted that redesign of the conventional cam system to decrease the number of yarn/metal contact surfaces may reduce the values of Tk by 70% for high-friction yarns and by 50% for low-friction yarns, for the same cam setting and input tension.
Wet-Fixation Process for Improved Durable-Press Cotton1
Authors: Hollies Norman R. S. , Getchell Nelson F. 
Published: March 2007

This paper is concerned with a new research development for imparting durable press to cotton in which finishing resins are deposited inside the wet, swollen cotton fiber. This is accomplished by padding an N-methylol resin-mineral acid solution on the fabric, heating the fabric in a closed or semi-closed container for 15 min at 180° F, neutralizing in sodium carbonate solution, washing, and drying. The heating results in deposition of the resin in the fiber in such a manner that it is not removed by washing and so sustains the fibers in a somewhat swollen condition. Subsequent application of cross-linking catalyst followed by a high-temperature dry cure results in only modest loss of fabric strength compared with conventional pad-dry-cure processing. The key to arriving at good strength properties of the finished fabric and high levels of fabric performance, both in resistance to wrinkling and good crease retention, lies in the use of two resin components. One of these, called a polymer builder, acts to swell the fibers and keep them in a swollen state (melamines are particularly effective in this regard) ; the second component is primarily a cross-linking agent for cotton, contributing only moderately to the swelling of the fiber but enhancing wet wrinkle recovery and, once catalyzed and dried, imparting high dry wrinkle recovery to the fabric (dihydroxy dimethylolethylene urea and methylol carbamates are good examples of this class). A total dry resin add-on of 8% to 15% is required to achieve the enhancement of fabric properties. Resin combinations for use on colored goods and white fabrics have been developed. A twill fabric treated by this process in the laboratory gave breaking strength retention values of 60% (filling), dry wrinkle recovery values of 300 degrees, and wash- wear ratings of 5. This fabric, converted to simulated trouser cuffs, showed less wear in laundering than cuffs conventionally finished by pad-dry-cure at comparable perform ance levels. In 20 laundering and tumble-drying cycles, most of the wet-fixed samples were not worn, whereas the pad-dry-cure controls all failed, on the average, at the sixth cycle. Similar results have been obtained in other abrasion tests.
Carbamate-Catalyst Systems for Low-Temperature, Rapid Curing of Alkyl and Alkoxyalkyl Carbamate Finishing Agents1
Authors: Goodman H.G. , Lourigan G.H. , Dupraz C.A. 
Published: March 2007

The greater lubricity of the alkyl ethers of alkylene glycols, in comparison to that of their corresponding alkanol analogs, suggested that the lubricating properties of the glycol ethers might be transmitted to their respective carbamic acid esters and, in turn, through suitable methylol derivatives, to fabric treated therewith. Increased inter- , molecular lubricity within the finished fabric might lead to improved tear strength, abrasion resistance, and fabric hand. To this end, a new class of carbamates, the alkoxyalkyl carbamates, based on polyalkylene glycols and certain of their alkyl ethers, have been investigated as finishing agents for cellulose. The relation of the chemical structure of the carbamate to the properties of fabric finished with the methylolated carbamate is discussed. Data are presented to illustrate the suitability of methylolated methoxyethyl carbamate as a cellulose reactant. In addition, the techniques employed in preparing carbamate finishes have been studied and the influence of methylolation conditions, such as formaldehyde/carbamate molar ratio; initial methylolation pH, and reaction temperature on both finish composition and performance properties is examined. An attempt to reduce or eliminate certain difficulties encountered in large-scale carbamate finishing led to the development of a new carbamate-catalyst system. This unusually efficient carbamate-catalyst system is discussed in detail and its low-tempera ture, rapid-cure characteristics are demonstrated.
Sonic and Ultrasonic Irradiation of Cotton Fibers
Authors: Boucher R.M.G. , Staples M.L. 
Published: March 2007

An investigation was made of the effect to exposure of high-intensity airborne acoustic waves on the physical and chemical properties of Deltapine and Acala 4-42 cotton. From the results of our experiments it appears that, with the exception of small changes in tensile strength, the fibers of both varieties of cotton do not seem significantly modified until one reaches the threshold of cellulose combustion. It has also been clearly estab lished that the most important factors which control sound to heat degradation in cotton fibers mass are the apparent density of the fibers bundle and the amount of acoustic energy radiated per gram of sample. It has also been shown that at equal intensity levels the sound degradation mechanisms seem to be frequency dependent and exhibit a maximum in the 22 kcps region. The peak sound intensity at any point of an irradiated fibers bundle determines the flash point of cellulose combustion. Regarding sound degradation rate and combustion threshold, no significant difference was noted between the Deltapine cotton grown under conditions of natural rainfall and the Acala 4-42 grown under irrigated conditions. It has also been confirmed that due to rapid sound degradation and damping phenomena high intensity airborne acoustic waves are of very little help to separate trash from cotton fiber masses.
The Tumble-Drying Process and Acrylic Knitted Fabrics1
Authors: Hurley R.B. 
Published: March 2007

The tumble-drying process is discussed relative to its effect on the dimensional stability of acrylic knitted fabrics. Area shrinkage of these fabrics increases with increase in tumble-dryer temperature. Cycling of the temperature during drying is shown to contribute significantly to variability in fabric shrinkage. Fabric compaction or compression during tumble drying is shown to promote longi tudinal or along-wale loop slippage, if the stitch length is sufficiently large so as to allow free distance between loop apices in adjacent rows of needle and sinker loops. Loop slippage is shown to occur without appreciable relaxation shrinkage under certain conditions during tumble drying after dry cleaning. The mechanism of compressional shrinkage is proposed as an explanation of some anomalies involving tumble drying reported in the literature.
Weaving Processes-Effects of Non-Preemptive Priority and Operator Interference on Output
Authors: Hines William W. , Nass Alan W. , Flege Raymond K. 
Published: March 2007

Warp yarns are depleted in the weaving process and must be replaced. Principles of queueing theory are applied to warp beam replacement. Looms may be serviced with new warp beams on a first-come-first-served or on a priority basis. Comparative studies have been made to determine the queueing dis cipline that would maximize loom output or loom operating efficiency for the same number of repairmen. Monte Carlo methods have been used for examining the queueing process. The actual universe of looms was replaced by a mathematical model that was demonstrated to be theoretically equivalent to the actual universe. For the particular system investigated, the priority queue discipline proved to be marginally more economical than the first-come-first-served discipline. The effectiveness of simulation as a tool for this type of study has been demonstrated.
Thermoanalytical Studies on the Durable-Press Curing of Cellulose
Authors: Miller Bernard 
Published: March 2007

In the course of a series of thermoanalytical investigations on durable-press curing processes for cotton, attention has been focused on the acid salt catalysts. Studies on the sequence and nature of the chemical events occurring during heating through the tem perature range of a typical durable-press cure have been carried out by using differential thermal analysis ( DTA ) and thermogravimetric analysis (TGA). Different methods of combining cotton and salt were compared. In one sequence, cotton was soaked with aqueous salt solutions; in another, the two solids were separated from each' other by a porous barrier. In a few instances, an aminoplast cross-linking resin was included in the reaction system. Among the detectable processes, when nitrate salts were used, was a strongly exo thermic reaction accompanied by a rapid weight loss, not characteristic of any one of the substances in the mixtures. This decomposition could be modulated with respect to temperature, rate, and extent, depending on the concentration, environment, and geo metric arrangement of the system. In an attempt to explain these effects additional studies on zinc nitrate were carried out showing that its thermal behavior was not what might be implied from values stated in the cited literature. On the basis of the accumu lated data, it is suggested that the exothermic decomposition is the consequence of the oxidative attack of NO2 on cellulose, the former being produced by the thermal breakdown of the nitrate salt.
Improved Durable-Press Cottons Produced by Conventional Pad-Dry-Cure Procedures Using Pairs of Monofunctional and Difunctional Swelling Reactants 1
Authors: Gagliardi D.D. , Wehner A. , Cicione R.J. 
Published: March 2007

Results are reported of attempts to develop a single-bath treating mixture containing a pair of monofunctional and a difunctional cellulose swelling reactants. A variety of monofunctional cellulose swelling reactants were prepared and tested with several cellu lose cross-linking agents. Some of the monofunctional reagents showed only minor improvements in fabric strength properties. Others, with selected cross-linking agents, showed substantial improvement. With selected monoheterocyclic ureas, N-methylol acetamide produced durable-press 100% cotton with higher tensile, toughness, and abrasion resistance than the control treatments. These results have been confirmed by cuff laundering tests. An analysis is presented of the interactions of the different pairs of reactants and the mechanism of improved properties produced thereby. The degree of overall strength improvement found with selected pairs varies with the concentration of each reagent. , Highest improvements are produced at high total solids concentrations where cotton swelling by the reagents, is very high. These high concentrations, however, may be economically impractical. At total solids level of 15-25%, a major improvement in all cotton fabric properties, is produced. At the present time, it is not known whether each reagent reacts independently with cellulose or whether some interaction between the two swelling reactants takes place during curing. Current emphasis is directed to the synthesis of optimum pairs of reagents, although useful candidates have already been developed for practical use in precure or delayed-cure systems. The advantage of the present process is that it can be done under conventional finishing-plant treating conditions.
Studies on Hook Formation and Cylinder Loading on the Cotton Card
Authors: Ghosh G.C. , Bhaduri S.N. 
Published: March 2007

The effect of various carding parameters on hooking and loading characteristics and on yarn quality has been investigated for a California 15/32 -in. cotton. Lickerin speeds and method of doffing the card web were shown to have no effect on the pattern of hook formation which is influenced mainly by cylinder and doffer speeds and the hank of the delivered sliver. These same factors also influence the loading on the cylinder and the coefhcient of transfer of fibers to the doffer. No clear-cut relationship between loading and hooking has, however, emerged. Increased doffer and cylinder speeds, at a constant carding rate, were seen to decrease yarn imperfections.
A Probability Model for Random Fiber Breakages
Authors: Lee Sung Won 
Published: March 2007

Applications of the probability model for random fiber breakage which was derived in Part I are demonstrated. The parameters of the model for an arbitrary initial fiber- length distribution are estimated by the nonlinear least-squares iterative method. Some practical uses of the estimates of parameters are shown. Different modes of fiber break age for two different lots of cotton due to opening-carding process are assessed in terms of average number of break points and probability of fiber breakage, thus, providing complete clarification to the fundamental questions raised at the beginning of the study and a realistic interpretation to the random fiber breakage phenomena. Results of the application show that the probability of fiber breakage on fiber length is moderately nonlinear and sizable three segments fiber breakage was seen to be present, especially for long fiber groups, although in an over-all sense it was fairly small. Fiber breakages into more than four segments were negligible. These will, of course, depend on the particular breakage process under study. It is demonstrated that the model can be used to assess analytically whatever the mode of ordinary random fiber breakages, allowing more flexible relation between breakage probability and fiber length and taking multi-segments fiber breakage into account.
Sewing Needle Temperature
Authors: Howard G. Michael , Parsons David 
Published: March 2007

The general problem of sewing-needle temperature rise due to frictional heat genera tion is discussed. Several possible mathematical models which could be used to predict needle temperatures are considered. The solution of even the simplest model which seems capable of giving accurate results would require extensive use of a high-speed digital computer. Because the parameters which govern the frictional heat generation and convective heat-loss mechanisms cannot be predicted with any accuracy, the probable computer results do not seem worth the effort required to obtain them. A very simple calculation of heat losses indicates that the thermal conductivity of the needle is the most important property governing needle heat dissipation. An experimental method of determining the needle temperature by infrared flux measurements is described. The many variables, such as emissivity, geometrical view factors, and signal shape and frequency which relate the flux to the needle tempera ture, are discussed. A calibration procedure is described which eliminates these factors as variables and permits determination of the peak needle temperature with an accuracy of ±2°C.
Studies in Wool Yellowing
Authors: Lennox F.G. , King M.G. 
Published: March 2007

Changes in the yellowness of wool during exposure to sunlight or to an artificial source resembling sunlight (the Xenotest) depend not only on the relative proportions of blue light and uv radiation, which cause partial bleaching and yellowing, respectively, but also on the exposure period and on the initial natural yellowness of the sample. The bleaching reaction is rapid and short-lived and is most pronounced with deeply yellow wools, whereas uv yellowing is more apparent with paler specimens and is sustained throughout irradiation. Even with the deeply yellow samples, the uv yellow ing reaction eventually supervenes and proceeds at a similar rate for all wools, although the level of yellowness at any particular stage of irradiation varies from one wool to another. A linear relationship exists between the initial natural yellowness of scoured wool and the change in yellowness during Xenotest irradiation for any particular period. Action spectra for changes in shade of naturally yellow wool and of wool after yellow ing in the laboratory by either uv radiation, dry heat, or hot alkaline buffer are similar. yellowness increasing to a maximum with decrease in wavelength down to 300-320 mμ (the lowest waveband examined) and decreasing to a minimum at 440-460 mμ in the blue region. However, the absorption spectra determined by the o-dichlorobenzene immersion method differ and so, in general, do the changes in yellowness during irradiation in the Xenotest. Natural yellowness is more likely to be attributable to the deposition of a thin pigment layer at the surface of the wool fiber than to the effects of uv radiation, heat, or alkaline conditions while on the sheep. This important difference in the distribution of pigment between natural and artificially yellowed wools may suggest new methods of improving the color of wool.
Observations Concerning the Carbonization of Viscose Rayon Yarn
Authors: Ross Stanley E. 
Published: March 2007

The course of carbonization of continuous filament viscose rayon yarn was followed, using various experimental techniques. The disappearance of the cellulose hydroxyl function in the early stages of carbonization was determined by chemical means, and the factors of weight loss, shrinkage, carbon level, and resistivity were also determined. In addition, observations of selected samples using DTA and scanning electron micros copy techniques were also carried out. The experimental data indicate that the reaction which occurs at 230-260°C involving a major loss in weight of the viscose is preceded by a cross-linking reaction involving the cellulosic hydroxyl groups. As the treatment temperature is increased, the yarn undergoes various other changes in properties, including a sharp reduction in resistivity beginning at a temperature of approximately 500°C. After exposure at approximately 1400°C, the carbon content of the yarn increases to a level of approximately 95%. Examination of the surface of carbon fibers with the scanning electron microscope shows a relatively unmarked surface bearing similar striations to the viscose precursor.
The Dynamics of Weft-Knitting Further Theoretical and Mechanical Analyses 1
Authors: Knapton James J. F. 
Published: March 2007

A computerized analytical technique for studying a mechanistic model of weft-knitted loop formation is described. This technique overcomes a previous deficiency of the model by allowing for the individual knitting tensions to be evaluated for any given set of knitting conditions. Consequently, each yarn and machine variable may now be studied independently, to investigate their individual effect on yarn knitting perform ance, machine efficiency, and quality of finished fabric. The results of studies on 18- and 36-gage linear cam systems show that the major vari ables are yarn friction and cam angle. Changes in input tension have only a second- order effect on yarn knitting performance. Great knitting advantages are hypothesized by the use of 60° linear cam systems over the conventional 45° designs for 18-gage equip ment, but little advantage is noted on 36-gage equipment for the same cam angle change. However, this work does suggest that present designs of 36-gage machines are inade quate, and new needle design features are sugested which are likely to radically improve the mechanical performance of this type of machinery.
Studies on Cellulolytic Micro-Organisms
Authors: Betrabet S.M. , Dasani Usha P. , Bhatt Indira G. 
Published: March 2007

Microbial degradation of cotton indigenous to the Bombay region of India was investi gated, with particular emphasis on cellulolytic nonfungal micro-organisms. About 76 bacteria, 49 actinomycetes, and 38 fungi were isolated by the enrichment culture technique from a arge number of cotton and fabric samples suspected of micro biological damage. Well known cellulolytic fungi belonging to genera Myrothecium, Chaetomium, Trichoderma, Memnoniella, etc and myxobacteria were conspicuously absent, whereas Streptomyces sp., which were encountered in fairly large numbers, seem to have an important role in the degradation of cotton along with Aspergilli. Bacteria, though incriminated in a large number, were mostly feeble in cellulolytic activity with the exception of isolates like Cellvibrio and Nocardia. Of particular interest was the large number of highly cellulolytie Streptomyces. This group has been isolated in a large number for the first time from cotton and fabric, though they have been known as cellulose digesters for a long time. Fungi, too, as expected, were highly cellulolytic. Aspergilli were most dominant. Penicillia and certain other fungi, even though not highly cellulolytic, were found in large numbers and were responsible for bad appearance, musty odor, and stains on cotton and fabric. The ecological pattern emerging from this study shows that cellulolysis in nature is a synergetic process, where fungi and streptomyces play a major role in bringing about degradation of cellulose, while bacteria, with few exceptions, seem to help mainly in the further decomposition of degraded cellulose. Bacteria, perhaps, may be devastating under very high humidity, bordering on wet conditions. Nutritional requirements of 15 cellulolytic isolates, mostly streptomyces, were also studied.
Use of Methods of Heterogeneous Chemical Kinetics and Nonequilibrium Thermodynamics for the Quantitative Evaluation of the Rate of Fixation of Reactive Dyes by Fibrous Materials 1
Authors: Krichevsk G.E. , Movshovich I.M. 
Published: March 2007

Dyeing and printing of fibrous materials with reactive dyes are examined as a problem of heterogeneous chemical kinetics. The rate of this fixation process is affected by the rate of supply of dye molecules to the active centers of the fiber, by the sorption capacity of the fiber, and by the rate of the two competing reactions of the adsorbed dye with the fiber and of the dye in the solution with water (hydrolysis). Each of the above enumerated stages of the fixation process is examined independently from a quantitative point of view, and the specificity of the mechanisms of these stages for reactive dyes is shown. Methods of heterogeneous chemical kinetics are proposed and applied for the quantitative evaluation of the rate of fixation of reactive dyes by the fibers and materials. These have made it possible to derive and solve, for definite boundary conditions, the kinetic equations that describe the rate of fixation of active dyes by the cellulosic fiber. It is shown that it is expedient to utilize simplified solutions of the kinetic equations for the fixation process in the kinetic and the diffusion regions.