Band 7, Heft 2

During the last thirty years there has been a rapidly growing interest in the field of genetic algorithms (GAs). The field is at a stage of tremendous growth, as evidenced by the increasing number of conferences, workshops, and papers concerning it, as well as the emergence of a central journal for the field. With their great robustness, genetic algorithms have proven to be a promising technique for many optimisation, design, control, and machine learning applications. This paper presents a new technique for detecting the source of fault in spinning mills from spectrograms by using genetic algorithm.

The appearance of a fabric can be greatly affected if the yarn has a sufficiently pronounced periodic component. The severity of the periodic fault can only be estimated if its intensity is quantified. Even though a spectrogram is more reliable than other tools at determining periodicity, it gives only the resolved mass variation, which may not be present in the final yarn when different faults are superimposed. The relative index of irregularity of yarn is considered as a measure of the intensity of a periodic fault of a spun yarn. By correlating the above index with the relative unlevelness indices of finished fabrics knitted from yarn samples produced at different levels of roller eccentricity, we have established the threshold value of the relative index of irregularity of yarn which produces worse appearance values in the fabric.

This paper proves relations, which concern the structure of knitted fabric by using a simple geometrical model. In addition, a series of graphics are made which allow fast, simple and effective analysis of the relations between some of the parameters of the knitting process and these of the ready-knit fabric. The quantity ‘relative geometrical prolongation of the thread length in the stitch’, introduced by me plays a significant role in this study. The relations given below allow the machine gauge to be defined; this helps to produce knit fabric with precisely calculated density by choosing appropriate values for the thread’s sinking depth and acceptable average geometrical prolongation.

Moisture transmission through textiles has a great influence on the thermo-physiological comfort of the human body which is maintained by perspiring both in vapour and liquid form. The clothing to be worn should allow this perspiration to be transferred to the atmosphere in order to maintaining the thermal balance of the body. Diffusion, absorption-desorption and convection of vapour perspiration along with wetting and wicking of liquid perspiration play a significant role in maintaining thermo-physiological comfort. The scientific understanding of the processes involved in moisture transmission through textiles and the factors affecting these processes are important to designing fabrics and clothing assemblies with efficient moisture transfer in different environment and workload conditions. This paper is in two parts. Part I focuses on the moisture transmission through textile materials and it discusses the processes involved in moisture transmission and the key influencing factors at play to maintaining comfort. It is underlined that the processes which play the major role in moisture transmission in a particular situation are dependant on the moisture content of the fabric, the type of material used, the perspiration rate and the atmospheric conditions, such as humidity, temperature and wind speed. Part II is concerned with the selection of the measurement techniques which are of great importance in determining fabric factors that influence comfort. The instruments and methods used for testing purposes should adequately simulate the exact conditions for which the fabric will be used, in order to determine the effectiveness of that fabric for a particular wearing situation and environmental condition. The testing methods used and the apparatus developed by different researchers for determining moisture transmission through textiles by different mechanisms are discussed in this paper. Moreover, this part of the paper deals with the mathematical models of liquid and vapour transport through textile materials developed by several scientists in order to understand the exact phenomena involved and to predict the factors affecting the transmission under a particular condition. When designing the comfort of a clothing product for a particular application, the requirements may result from needs concerning the application, the individual wearer and the environmental conditions.

Poly (styrene-co-butyl acrylate) latex was prepared with a 70:30 weight ratio of styrene to butyl acrylate. The prepared latex was incorporated with various weight percentages of cornstarch. The cornstarch-filled copolymer latex was used as a matrix to fabricate the polyester nonwoven fabric reinforced composites. The pickup ratio of latex to fabric was maintained at 3.2:1. The moisture sorption characteristics of composites were examined at 27 0 C for water activity (aw) from 0.1 to 0.9. The sorption data was used to fit six different sorption isotherm models proposed in the literature. The model constants were determined by linear fitting of the sorption equations. The ranges of applicability of water activity for the isotherm models reported in the article lies between 0.1 and 0.4 (monomolecular layer) for the Braunauer-Emmet-Teller (BET) model, and between 0.3 and 0.9 (multimolecular and capillary condensation layers) for other models. The value of the coefficient of determination (R2 = 0.97±0.02) confirms the linear fitting of the equations studied.

This paper deals with the graft co-polymerisation of methylmethacrylate (MMA) onto flax fibre under the influence of microwave radiation (MWR). The graft co-polymers are characterised by FTIR spectroscopy, scanning electron microscopy (SEM), thermal analysis (TGA/DTA) and X-ray diffraction (XRD). Graft co-polymers are subjected to the evaluation of some physical, chemical and mechanical properties. Graft co-polymers thus prepared are used in the preparation of phenol-formaldehyde composites. Wear resistance, tensile strength and compressive strength of composites are measured, and it is found that composites reinforced with flax-g-poly(MMA) showed better mechanical properties in comparison to composites reinforced with raw flax.

Dentistry has advanced to the use of FRCs, which helps patients to live their lifetime with their dentition intact. A large number of developments in the field of fibrous composite implants and devices for orthopaedic and dental applications have taken place. The present paper discusses the applications of fibre- and textile-reinforced composites in dental practices, mainly focussing on periodontal splinting. The conventional methods of splinting and the design & use of fibre-reinforced composites as restoratives to stabilise and splint teeth have been discussed in detail. The current controversy of incorporating implants in patients requiring splinting is discussed in relation to the various fibres applied as reinforcement for the splinting material.