Green chemistry and the textile industry

In contrast to non-sustainable, non-renewable fossil-fuel-based conventional chemical processes, so-called green reactions are sustainable, highly-efficient (fewer steps, fewer resources, less waste) and stable under ambient conditions and much more eco-friendly (achieved by the use of non-hazardous solvents and less-hazardous, minimized waste). They are assessed by 12 principles established by Anastas and Warner [Green Chemistry: Theory and Practice, Oxford University Press, New York, 1998]. Recently steps have been taken to make textile materials and processing more environmentally friendly (or ‘greener’), including fibre production, dyes and auxiliaries, solvents, optimized and efficient processing with recycling of water and chemicals, bio-processing, the elimination of hazardous chemicals and the recycling of textile materials, and whilst it is acknowledged that mechanical aspects of textile processing also contribute to achievement of sustainability, this review focuses on the chemistry deployed.     

Luminol-Based Enhanced Chemiluminescence Assay for Quantification of Peroxidase and Hydrogen Peroxide in Aqueous Solutions: Effect of Reagent pH and Ionic Strength

The effect of reagent pH and ionic strength was evaluated on the horseradish peroxidase (HRP)-luminol-p-iodophenol enhanced chemiluminescence assay. This assay was optimized for HRP and H2O2 quantification during enzyme-mediated remediation of groundwater or wastewater contaminated with phenolic chemicals. The maximum chemiluminescence intensity (ICLmax) and total area under the chemiluminescence intensity profiles were measured as a function of p-iodophenol concentration, reagent solution pH, and reagent ionic strength. ICLmax values were optimum at pH 8.5 and increased linearly with reagent ionic strength. Optimum chemiluminescence enhancement was produced at a p-iodophenol concentration of 0.3 mM under the reaction conditions. ICLmax values were linearly correlated with HRP and H2O2 concentrations within the ranges of 0.1–1 activity units/mL and 0.1–1 mM, respectively. Results indicate that the HRP-luminol-p-iodohenol enhanced chemiluminescence assay has a potential to be used for quantification of HRP activity and H2O2 concentration in aqueous solutions encountered in groundwater remediation or wastewater treatment scenarios.     

Investigations of the effect of non-uniform insert pitch on vibration during face milling

In the present work optimal tooth spacing vs spectral redistribution criteria for face milling has been used as one of the methods for vibration control. A special milling cutter with non-uniform pitch has been designed and fabricated and its effect on machine tool vibration is studied. The frequency response spectrum of the machine tool is found out analytically using Finite Element Programme. The spacing between the teeth of milling cutters is found out by minimizing the total power of the relative cutter-workpiece vibration. The newly designed cutter is fabricated and tested experimentally to determine its effectiveness when compared with a standard cutter with evenly spaced inserts.     

Neuere Untersuchungen über das Aluminium-Sauerstoff-Gleichgewicht in Eisenschmelzen

Laboratoriumsuntersuchungen zur Ermittlung des Gleichgewichtes für die Desoxydation von sauerstoffhaltigen Eisenschmelzen mit Aluminium unter Anwendung einer Kalk-Tonerde-Schlacke zur Raffination der Schmelze und bei Spülen der Schmelze mit hochreinem Argon. Erörterung der Einflüsse von nicht abgeschiedenen feinen Oxidsuspensionen und von metastabilen Übersättigungserscheinungen auf die in früheren Arbeiten gefundenen Abweichungen der Versuchswerte von thermodynamisch berechneten Gleichgewichtswerten. Bestimmung der Wirkungsparameter e₀^Al für die Wirkung von Aluminium auf Sauerstoff bei 1600, 1650 und 1700 °C und Berechnung der Temperaturabhängigkeit der Gleichgewichtskonstanten für die Reaktion zwischen Aluminium und Sauerstoff im flüssigen Eisen. Ermittlung der Wirkung von Mangan und Silicium auf die Gleichgewichtslage der Desoxydationsreaktion mit Aluminium. Aus Abschätzungen der Einschlußgrößen und der Wachstumszeiten durch Diffusion sowie aus elektronenmikroskopischen Untersuchungen der Oxidsuspensionen Folgerungen über in der Schmelze verbleibende Oxidpartikel als Grund für Abweichungen vom berechneten Gleichgewicht. Anhang mit der Berechnung der freien Grenzflächenenergien für die Tonerdeabscheidung unter neutraler Gasatmosphäre sowie unter Kalk-Tonerde-Schlacken.     

Categorization of Hindi phonemes by neural networks

The prime objective of this paper is to conduct phoneme categorization experiments for Indian languages. In this direction a major effort has been made to categorize Hindi phonemes using a time delay neural network (TDNN), and compare the recognition scores with other languages. A total of six neural nets aimed at the major coarse of phonetic classes in Hindi were trained. Evaluation of each net on 350 training tokens and 40 test tokens revealed a 99% recognition rate for vowel classes, 87% for unvoiced stops, 82% for voiced stops, 94.7% for semi vowels, 98.1% for nasals and 96.4% for fricatives. A new feature vector normalisation technique has been proposed to improve the recognition scores.     

A high-performance application data environment for large-scale scientific computations

Effective high-level data management is becoming an important issue with more and more scientific applications manipulating huge amounts of secondary-storage and tertiary-storage data using parallel processors. A major problem facing the current solutions to this data management problem is that these solutions either require a deep understanding of specific data storage architectures and file layouts to obtain the best performance (as in high-performance storage management systems and parallel file systems), or they sacrifice significant performance in exchange for ease-of-use and portability (as in traditional database management systems). We discuss the design, implementation, and evaluation of a novel application development environment for scientific computations. This environment includes a number of components that make it easy for the programmers to code and run their applications without much programming effort and, at the same time, to harness the available computational and storage power on parallel architectures.     

Influence of interaction promoter on the properties of thermoplastic elastomeric blends of natural rubber and polyethylene

The influence of a third component as interaction promoter on the properties of natural rubber-polyethylene thermoplastic blends, both uncured and cured, has been studied. The third component chosen has some structural similarity with polyethylene and is amorphous in nature. Ethylene propylene diene (EPDM) rubber, chlorinated polyethylene and chlorosulphonated polyethylene have been used as the third component. All the third components have better adhesion with the plastic phase and the rubber phase. The adhesive strength is highest with EPDM. The properties are improved by using the above third components both for cured and uncured blends. In comparing the properties, the strength of the composite is divided by the modulus of the composite to take care of the hard-phase contribution. The size of the dispersed domain is reduced by using the third component and is approximately 1.2 m. All the properties could be explained in terms of the strengths of the individual phases, the morphology and the adhesion between components.