There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

Biocomposites reinforced with natural fibers: 2000–2010

This century has witnessed remarkable achievements in green technology in material science through the development of natural fiber reinforced composites. The development of high-performance engineering products made from natural resources is increasing worldwide day by day. There is increasing interest in materials demonstrating efficient use of renewable resources. Nowadays, more than ever, companies are faced with opportunities and choices in material innovations. Due to the challenges of petroleum-based products and the need to find renewable solutions, more and more companies are looking at natural fiber composite materials. The primary driving forces for new bio-composite materials are the cost of natural fibers (currently priced at one-third of the cost of glass fiber or less), weight reduction (these fibers are half the weight of glass fiber), recycling (natural fiber composites are easier to recycle) and the desire for green products. This Review provides an overview of natural fiber reinfocred composites focusing on natural fiber types and sources, processing methods, modification of fibers, matrices (petrochemical and renewable), and their mechanical performance. It also focuses on future research, recent developments and applications and concludes with key issues that need to be resolved. This article critically summarizes the essential findings of the mostly readily utilized reinforced natural fibers in polymeric composite materials and their performance from 2000 to 2013.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/mame.201300008

Progress Report on Natural Fiber Reinforced Composites

Fibre-reinforced composites are rapidly gaining market share in structural applications, but further growth is limited by their lack of toughness. Fibre hybridisation is a promising strategy to toughen composite materials. By combining two or more fibre types, these hybrid composites offer a better balance in mechanical properties than non-hybrid composites. Predicting their mechanical properties is challenging due to the synergistic effects between both fibres. This review aims to explain basic mechanisms of these hybrid effects and describes the state-of-the-art models to predict them. An overview of the tensile, flexural, impact and fatigue properties of hybrid composites is presented to aid in optimal design of hybrid composites. Finally, some current trends in fibre hybridisation, such as pseudo-ductility, are described.

/pdf/fibre-hybridisation-in-polymer-composites-a-review-gcnp0ezsc7.pdf

Fibre hybridisation in polymer composites: a review

Partial dissolution of precipitated-calcium carbonate (P-CaCO3) in electroless nickel-phosphorus (Ni-P) coating and its surface characterization

This paper deals with an input-based half car vehicle model moving with constant velocity over a terrain surface, where MR damper is fixed in both the wheels. The half car model fixed in a rolling dynamometer is operated with various input frequencies corresponding to various speeds. To design and develop control algorithms that will give optimum benefits of the unique features of the MR damper, models have been developed which adequately characterize the damper’s genuine, natural nonlinear behavior. The controller controls both the dampers according to variations in parameters of road surface, speed and load etc., with an advanced time with a particular time bound, through input (pre-programmed) based skyhook on/off control system. Comparison of experimental results of input based and ordinary skyhook on/off results indicates that the model is more functional and rewarding for vibration suppression over a wide range of operating conditions and is passable for control design and analysis.

Input advanced control of semi active half car heave model

In this work, mechanical and tribological behaviour of AA7075/Al2O3/graphite hybrid composite was studied. Pin-on-disc machine was used for the conductance of the wear test. The composites with 2-8 wt.% Al2O3 particles were processed by conventional liquid casting method. For the hybrid composite, 5 wt.% graphite were commonly added to the base alloy. The hardness of the composites was measured using a Vickers hardness tester and their tensile strength was measured by an universal testing machine (UTM). Scanning electron microscopy (SEM) was used to analyse worn surfaces of samples. It was found that an increase in Al2O3 content reduced the coefficient of friction up to 6 wt.% and thereon slightly increased. But this effect was reverse in hybrid composites and AA 7075 / Graphite composites. Hardness and tensile strength of composites increased with increasing Al2O3 content in both cases. The wear rates for both composites and hybrid composites were dependent on Al2O3 content in the alloy. Al/Al2O3 composites containing 6 wt.% Al2O3 exhibited superior wear properties over the base alloy, and hybrid composites.

Mechanical and tribological behaviour of graphite- reinforced aluminium matrix composites

Calcium hexaboride reinforced Nickel-Phosphorus composite coating for increasing the wear properties of low carbon steel

Plain GFRP laminates and stainless steel (SS) wire reinforced GFRP laminates were prepared by hand layup method. The composite specimen reinforced with SS wires placed at various pitch distances was fabricated, and drop-weight impact tests were conducted with velocities of 2.80, 3.13 and 3.43 m/s. The impact damage area was evaluated by using lighting technique, and fracture behaviors were analyzed using scanning electron microscopic images. Impact energy absorption and damage area due to low-velocity impact on the GFRP composites without wires and SS wire reinforced GFRP composites were calculated, and efficiency of absorption was compared with respect to impact velocity and pitch distance.

A. Elayaperumal

Papers

Partial dissolution of precipitated-calcium carbonate (P-CaCO3) in electroless nickel-phosphorus (Ni-P) coating and its surface characterization

Input advanced control of semi active half car heave model

Mechanical and tribological behaviour of graphite- reinforced aluminium matrix composites

Calcium hexaboride reinforced Nickel-Phosphorus composite coating for increasing the wear properties of low carbon steel

Influence of Stainless Steel Wire Reinforcement on the Impact Resistance of GFRP Composite Laminates