Characterization of Physical, Chemical and Mechanical Properties of Sri Lankan Coir Fibers

Polyurethanes synthesized from diols of low, medium and high molecular weight ( Mw = 1000, 2000 and 3000 respectively) with low free isocyanates were used to fabricate coated fabrics. The physical, chemical and mechanical properties of these coated fabrics and polymer films were studied to establish their suitability for fabricating collapsible fuel tanks to store diesel for long periods under adverse conditions. Fabrics coated with low molecular weight polyurethanes are found to be more suitable for storing diesel fuel compared with those coated with medium and high molecular weight polyurethanes.

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Microstructural and fractographic characterization of B4C-Al cermets tested under dynamic and static loading

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100154780 ◽

1989 ◽

Vol 47 ◽

pp. 562-563

Author(s):

Gyeung Ho Kim ◽

Mehmet Sarikaya ◽

D. L. Milius ◽

I. A. Aksay

Keyword(s):

Thin Film ◽

Mechanical Properties ◽

Fracture Toughness ◽

Static Loading ◽

Carbon Deposition ◽

Full Density ◽

Unique Combination ◽

Strong Component ◽

Reaction Products

Cermets are designed to optimize the mechanical properties of ceramics (hard and strong component) and metals (ductile and tough component) into one system. However, the processing of such systems is a problem in obtaining fully dense composite without deleterious reaction products. In the lightweight (2.65 g/cc) B4C-Al cermet, many of the processing problems have been circumvented. It is now possible to process fully dense B4C-Al cermet with tailored microstructures and achieve unique combination of mechanical properties (fracture strength of over 600 MPa and fracture toughness of 12 MPa-m1/2). In this paper, microstructure and fractography of B4C-Al cermets, tested under dynamic and static loading conditions, are described.The cermet is prepared by infiltration of Al at 1150°C into partially sintered B4C compact under vacuum to full density. Fracture surface replicas were prepared by using cellulose acetate and thin-film carbon deposition. Samples were observed with a Philips 3000 at 100 kV.

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Characterization of interfaces in CVD-coated nicalon fiber-reinforced SiC

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100154755 ◽

1989 ◽

Vol 47 ◽

pp. 556-557

Author(s):

K.L. More ◽

R.A. Lowden

Keyword(s):

Mechanical Properties ◽

Fracture Toughness ◽

Chemical Vapor ◽

Chemical Vapor Infiltration ◽

Frictional Stress ◽

Fiber Reinforced ◽

Pull Out ◽

Carbon Coated ◽

Fiber Matrix

The mechanical properties of fiber-reinforced composites are directly related to the nature of the fiber-matrix bond. Fracture toughness is improved when debonding, crack deflection, and fiber pull-out occur which in turn depend on a weak interfacial bond. The interfacial characteristics of fiber-reinforced ceramics can be altered by applying thin coatings to the fibers prior to composite fabrication. In a previous study, Lowden and co-workers coated Nicalon fibers (Nippon Carbon Company) with silicon and carbon prior to chemical vapor infiltration with SiC and determined the influence of interfacial frictional stress on fracture phenomena. They found that the silicon-coated Nicalon fiber-reinforced SiC had low flexure strengths and brittle fracture whereas the composites containing carbon coated fibers exhibited improved strength and fracture toughness. In this study, coatings of boron or BN were applied to Nicalon fibers via chemical vapor deposition (CVD) and the fibers were subsequently incorporated in a SiC matrix. The fiber-matrix interfaces were characterized using transmission and scanning electron microscopy (TEM and SEM). Mechanical properties were determined and compared to those obtained for uncoated Nicalon fiber-reinforced SiC.

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USE OF STARCH SYRUPS IN THE PRODUCTION OF JELLY

International Conference on Technics Technologies and Education ◽

10.15547/ictte.2019.07.027 ◽

2019 ◽

pp. 457-462

Author(s):

Kateryna Iorgachova ◽

Olga Makarova ◽

Karyne Avetisian

Keyword(s):

Mechanical Properties ◽

Carbohydrate Composition ◽

Foam Layer ◽

Quality Indices ◽

Organoleptic Quality ◽

Physical Chemical

In the presented work the choice of starch syrup for the jelly products production has been substantiated. It was based on the analysis of the starch syrup carbohydrate profiles and recipes of jelly products. The influence of syrup on the rheological and structural-mechanical properties of jelly and aerated masses for a two-layer jelly has been determined. The expediency of polydextrose usage has been demonstrated. Its adding leads to the regulation of the jelly structure and foam layer for the samples with more than 50% of sugar replaced by starch syrup. Depending on the ratio of carbohydrates in jelly it was determined the amount of polydextrose adding of which provides the required firming and prebiotic properties of finish products. The change of physical-chemical, structural-mechanical, and organoleptic quality indices of two-layer jelly with modified carbohydrate composition has been investigated during storage.

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