A new method of evaluating the fineness and residual gum content of hemp fibres

The demand for eco-friendly apparel and technical textiles has led to a resurgence of interests in bast fibres such as hemp. The lack of fast and objective evaluation of the quality attributes of bast fibres has been a major barrier to the advancement of the bast fibre industry. One of the most important quality attributes of a fibre is its fineness. For bast fibres, the fibre fineness measurement can also reflect the degree of fibre separation during retting or degumming. The traditional method of evaluating the fineness and residual gum content of bast fibres is a very tedious process. In this paper, degummed hemp fibres have been measured for fineness on an Optical Fibre Diameter Analyser (OFDA), and the results have been co-related with the residual gum content in the fibre samples. Since hemp fibres do not have a circular cross section, it is the width of the fibre that gets measured by the OFDA instrument, and this width has been used as an indication of the fibre fineness in this paper. The findings from this study suggest that the optical method can provide a fast and objective way of evaluating the fineness of hemp fibres, and that there is a good correlation between the fibre „width‟ measurement and the residual gum content.

Determining residual gum content of bast fibres

The measurement of fibre quality in bast fibres is related to the amount of gum (lignin, hemicellulose, wax and pectin) left in the fibre after the retting process. Large amounts of gums present represent poor separation of fibre. Efficiency of retting can be monitored by measuring the residual gum content of the retted fibre.

This paper investigated the use of ultrasonic vibration combined with chemical retting as a pre-treatment to improve accuracy of traditional residual gum content test. Work was conducted on chemically retted hemp fibre. Pre-treatment conditions were analysed by determining the best chemical combination, chemical concentration and treatment time. Fibres were examined for successful separation using optical microscopy and optical fibre diameter analysis (OFDA). The work proposed a new method for determining the residual gum content of hemp fibre.

Application of identification techniques to determine effect of carbon content in steels on rheological parameters during hot deformation

The objective of the present work is searching for the correlation between the carbon content in steels and the parameters of the rheological models, which are used to describe the materials behavior during hot plastic deformation. This correlation can be expected in the internal variable models, which are based on physical phenomena occurring in the material. Such a model, based on the dislocation density as the internal variable, is investigated in this work. The experiments including hot torsion tests are used for the analysis.
The procedure is composed of three parts. Plastometric tests were performed for steels with various carbon content. Optimization techniques were applied next to determine the coefficients in the internal variable rheological model for these steels. Two versions of the model are considered. One is based on the average dislocation density and the second accounts for the distribution of dislocation densities. Evaluation of correlation between carbon content and such coefficients in the models as activation energy for self diffusion, activation energy for recrystallization, grain boundary mobility, recovery coefficient etc. was the main objective of the work. In consequence, the model which may be used for simulation of hot forming processes for steels with various chemical compositions, is proposed.

Content exploration for e-learning using XML Web services

Obtaining high quality content in an e-learning portal is critical to maximise the learning experience. For e-learning portals the content specialists are the publishers. Typically, publishers are nominated by portal administrators to make their content available to instructors. Instructors subsequently customise the portal by selecting content according to their requirements. The choice of content is limited to that provided by the publishers. This is a rigid system owing to the fact that instructors do not have access to an exhaustive range of content. We propose a system based on XML Web services which can be adopted by publishers in adherence with a number of emerging Web standards including SOAP and UDDI to disseminate their content. This system can be leveraged by portals to preview and subsequently acquire content which best suits the requirements as determined by instructors.

Technology and management systems for digital rights and content: the editors friend

Since the late 1980s, when authors began to deliver typescripts to their publishers on disk, the process of editing and publishing books has been in an almost constant state of change. Not only has digital technology enabled a conflation of book production processes, but books themselves are increasingly available in a wider choice of delivery modes. From traditional hard cover and paperback books, to digital files formatted for printing on desktop printers, to files specifically prepared for delivery via hand-held electronic book-reading devices, to text designed to be read on screen (incorporating hyperlinks that facilitate the reader's ability to navigate around the text and between texts), the consumer now has potential myriad choices for delivery of their chosen content. And the publisher, it seems, has myriad ways to deliver content and to seek and satisfy new markets. As well as opportunities, these changes have caused disruption to the traditional supply chain.

This paper focuses on changes to the role of the editor caused by the digitisation of the publishing industry.