It is about fifteen years since we started hearing about Computational Ma terials Science and Materials Modelling and Design. Fifteen years is a long time and all of us realise that the use of computational methods in the design of materials has not been rapid enough. We also know the reasons for this. Mate rials properties are not dependent on a single phenomenon. The properties of materials cover a wide range from electronic, thermal, mechanical to chemical and electro-chemical. Each of these class of properties depend on specific phe nomenon that takes place at different scales or levels of length from sub atomic to visible length levels. The energies controlling the phenomena also varies widely from a fraction of an electron volt to many joules. The complexity of materials are such that while models and methods for treating individual phenomenon have been perfected, incorporating them into a single programme taking into account the synergism is a formidable task. Two specific areas where the progress has been very rapid and substantive are prediction of phase stability and phase diagrams and embrittlement of steels by metalloids. The first three sections of the book contain papers which review the theoreti cal principles underlying materials modeling and simulations and show how they can be applied to the problems just mentioned. There is now a strong interest in designing new materials starting from nanoparticles and clusters."

Compressional behaviour has been studied during tensile loading with respect to mass per unit area, needling density, depth of penetration, wetting of fabric etc. Empirical equations for compression and recovery curves of needle punched nonwoven fabrics from jute, jute-polypropylene blend and polypropylene have been suggested and behaviours are described with two dimensionless parameters and . A mathematical model has been developed relating the compressional behaviour and parameters, i.e. needling density, depth of penetration and mass per unit area of jute needle punched nonwoven. A good correlation has been observed between compressional parameter ( ) or recovery parameter ( ) and the properties i.e. tenacity, elongation-at-break, energy to break, air permeability and thermal insulation of jute needle punched nonwoven fabrics. Effect of repeated compression-recovery cycles, dynamic loading, rate of deformation, ultimate compressional load, duration of loading, duration after recovery and comparison between different testing principles have been studied and analysed.

This monograph is intended to present an overview- most of which is based on ideas and conclusions presented in published literature, the rest representing our own concepts developed through extensive research. Here, the reader will discover the rational relationships between basic mechanisms, and experimental data, and theoretical expressions which were developed over several years by scientists for coir fibre characterisation and utilisation in particular. It will help to those who deal with coir fibre in both industry and academia specially to teachers, students and technologists. It contains the perspective of coir, its textile related structure and properties with a comparison between few other allied lingo-cellulosic fibres. Coir fibre are coarser for textile applications and possesses highly variable properties. So segregation of fibres from the bulk considering properties may give suitable fibre for spinning, composite making and other applications. The optimum value addition of coir can be realized, when a fully systematic supply chain of quality fibre with proper gradation system can be developed. The fibre shows high flexural rigidity and lower inter-fibre frictional resistance for which it is difficult to spin finer yarn and indicates its suitability for coarse textile applications. Coir fibre is circular and multi-fibrillar. Moisture regain is moderate. Thermal and component analyses reveal the presence of similar amount of lignin and celluloses in the fibre. SEM image reveals that surface of the fibre is waxy, irregular, and having micro-imperfections. Microbial resistance makes the coir suitable for using it in different engineering and geotechnical applications in conjunction with soil and water. The property-based advantages of coir are resistant to fungi and rot, excellent insulation against temperature, not easily combustible, flame-retardant, resistant to moisture and dampness, tough and durable, highly resilient, totally static free, easy to clean etc. It is not suitable for technical uses due to low strength, high extensibility and very low modulus. Sometimes high bulk and low coefficient of friction act as the disadvantages. The age old manual spinning technology should be replaced by mechanised system. The fibres can be highly suitable to form compressed mat for various products of geotextile, agro-textiles, and sound and heat insulators with improved softness and fineness property. Being an ecofriendly, natural product from renewable sources, coir products serve mankind in several ways as a substitute for many synthetic products which are extensively used but are harmful to nature. Coir wood substitute will help to protect valuable forests.