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Materials Science and Engineering

2008

Selected Works

Articles 1 - 5 of 5

Full-Text Articles in Engineering

A Transcendental To Changing Metal Powder Characteristics, Mahendra Kumar Trivedi, Rama Mohan Tallapragada Sep 2008

A Transcendental To Changing Metal Powder Characteristics, Mahendra Kumar Trivedi, Rama Mohan Tallapragada

Mahendra Kumar Trivedi

It’s not often that Metal Powder Report departs from the path of hard facts into the somewhat ‘mushier’ area of metaphysics, but opportunities crop up. While recognising that science has its fair share of charlatans, one such opportunity was presented by a paper submitted by an Indian researcher in which he details work aimed at probing the effects on powder samples where changes were apparently generated by thought. Some will laugh, others will cry, but perhaps among our readers there are those who might be able to help elucidate further the phenomena described…

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Anisotropic Contraction In Forisomes: Simple Models Won't Fit, Winfried Peters, Michael Knoblauch, Stephen Warmann, William Pickard, Amy Shen Mar 2008

Anisotropic Contraction In Forisomes: Simple Models Won't Fit, Winfried Peters, Michael Knoblauch, Stephen Warmann, William Pickard, Amy Shen

Winfried S. Peters

Forisomes are ATP-independent, Ca2+-driven contractile protein bodies acting as reversible valves in the phloem of plants of the legume family. Forisome contraction is anisotropic, as shrinkage in length is associated with radial expansion and vice versa. To test the hypothesis that changes in length and width are causally related, we monitored Ca2+- and pH-dependent deformations in the exceptionally large forisomes of Canavalia gladiata by high-speed photography, and computed time-courses of derived geometric parameters (including volume and surface area). Soybean forisomes, which in the resting state resemble those of Canavalia geometrically but have less than 2% of the volume, were also …

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Environmentally Benign Synthesis Of Nanosized Aluminophosphate Enhanced By Microwave Heating, Eng-Poh Ng, Luc Delmotte, Svetlana Mintova Dec 2007

Environmentally Benign Synthesis Of Nanosized Aluminophosphate Enhanced By Microwave Heating, Eng-Poh Ng, Luc Delmotte, Svetlana Mintova

Eng-Poh Ng

The problem addressed with our paper is on the efficient utilization of reacting materials for enhanced syntheses of nanosized aluminophosphate molecular sieve by microwave heating, and decreasing or almost eliminating the related waste. The synthesis procedure deals with the environmental issues concerning the future manufacture re-use and disposal of non-reacted chemicals associated with the production of nanosized aluminophosphate. Nanosized AlPO-18 has been prepared by a multicycle synthesis approach via re-using non-reacted compounds from precursor suspensions with minimal requirement of chemical compensation after recovering of crystalline nanoparticles from each step. This approach is implied as environmentally benign and results in almost …

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Validity Of The One-Dimensional Limp Model For Porous Media, Olivier Doutres, Nicolas Dauchez, Jean-Michel Génevaux, Olivier Dazel Dec 2007

Validity Of The One-Dimensional Limp Model For Porous Media, Olivier Doutres, Nicolas Dauchez, Jean-Michel Génevaux, Olivier Dazel

Olivier Doutres Ph.D.

A straightforward criterion for determining the validity of the limp model validity for porous materials is addressed here. The limp model is an “equivalent fluid” model which gives a better description of porous behavior than the well known “rigid frame” model. It is derived from the poroelastic Biot model, assuming that the frame has no bulk stiffness. A criterion is proposed for identifying the porous materials for which the limp model can be used. It relies on a new parameter, the Frame Stiffness Influence FSI, based on porous material properties. The critical values of FSI under which the limp model …

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Structure And Kinetics Of Internal Oxidation In Ag-Sn Alloys, Zeljko J. Kamberovic Dec 2007

Structure And Kinetics Of Internal Oxidation In Ag-Sn Alloys, Zeljko J. Kamberovic

Zeljko J Kamberovic

Internal oxidation in Ag-Sn-In-Te and Ag-Sn-Cu-Bi alloys was tested. Microstructures of casted and homogenized samples, as well as after internal oxidation were followed by optical microscopy. The structure of Ag-Sn-Cu-Bi alloy was found finer, and the oxidation rate is considerably higher compared to the Ag-Sn-In-Te type alloy sheets. It seems that the size and volume fraction of secondary phase particles (probably ζ type) can influence the process of internal oxidation. In the Ag-Sn-In-Te alloy type “wavy oxidation” was noticed with oxide free regions.

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