Materials Literature
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Composites based on chopped ultra high modulus polyethylene fibers (UHMPE) and low density polyethylene (LDPE) were prepared in the melt state. It is shown that the UHMPE fibers do not melt during the preparation operations, and an im portant enhancement of the mechanical properties is obtained as a function of fiber…
SiC composites (C/SiC) reinforced with unidirectionally oriented carbon fibers were fabricated by the pressureless sintering method completed with infiltration of polycarbosilane (PC). This method is effective for increasing density and strength of the composite.The open porosity of C/SiC of 10% was achieved after 10…
Abstract The combination membrane of poly(1‐trimethylsilyl‐1‐propyne) with enormously high permeability and poly(vinylimidazole)‐bound porphinatocobalt with selective oxygenbinding ability was prepared. Oxygen transport through the membrane was facilitated in terms of oxygen transport via the latter domain as a fixed…
To clarify the effect of alloying elements on transformation behavior of destabilization heat treated high chromium cast irons, specimens of high chromium hypoeutectic cast irons containing copper and molybdenum were destabilization heat treated at 900, 1000 and 1100°C for 5×102 to 5×104 sec and then rapidly cooled do…
Connective tissue substitute can be made of collagen sponge-shaped matrice which is reconstituted by freeze-drying a collagen dispersion. This procedure is then followed by a crosslinking treatment to decrease the in vivo biodegradation rate. In the present study, collagen dispersions made of collagen fibrils with a D…
We use density-functional theory to derive an expression for the distortion free energy of molecular ordered phases and expand it in terms of the order parameters characterizing the structure of the phase and the molecular correlation function of an effective isotropic liquid. We derive expressions for the elastic con…
Abstract A thick sedimentary section was penetrated at three sites in the West Central Pacific during the Ocean Driling Program (ODP) Leg 129. Although average core recovery ranged from 17.3 to 29.5%, recovery in some intervals falls as low as 0–5%. Furthermore, the recovered portion of the core is conventionally assi…
Sequential addition of 1,10-phenanthroline (phen) or 2,2′-bipyridine (bipy) followed by 3,5-di-tert-butyl-catechol (H2dtbc) to oxobis(pentane-2,4-dionato)vanadium(IV) yields [V(dtbc)2L](L = phen or bipy) which can be oxidised using Ag[SbF6] to give [V(dtbc)2L][SbF6]. The new compounds have been characterised by microa…
Dynamic analysis of air-jet filling insertion has been carried out both experimentally and theoretically for unsteady-state running conditions. In Part I of this series, analytical models for both loop- and drum-storage systems are developed to investigate the air-jet filling-insertion process. The flight of the yarn…
Basket handle porphyrins containing short p- or m-phenylenedimethylenedioxy chains covalently linked at the ortho position of phenyl groups of 5,10,15,20-tetraphenylporphyrin have been synthesised. Isomer I of the para derivative (H2LIa) and isomers II and III(H2LIIb and H2LIIIb) of the meta derivative have been chara…
Studies have been made on frequency-dependent electrical conduction in polycrystalline diamond films prepared by plasma-enhanced chemical vapor deposition (PECVD). It is found by ac conductivity measurements that the electrical conduction in annealed diamond films is attributed to frequency-independent band conduction…
Polydimethylsiloxane (PDMS) oil and crosslinked rubber react with hydroxylated surfaces, when heated at 250-300°C. PDMS is thus chemically bound to silicate glass sheets and to iron hydrous oxide particles. As a result, stable and adherent PDMS coatings may be obtained over glass, by heating silicone oil spread over g…
Hairiness is a parameter of interest to the textile technologist. The material and the machines used both influence the fuzziness of yarn. This paper reports the results of a preliminary investigation in which fuzziness is reduced by increasing the pressure of air around the point of twisting. The reduction in hairine…
Vibrational, NMR and dynamic NMR spectra, considered together with the results of theoretical studies, provide a complete and fairly accurate quantitative picture of the isomerism affecting the nitroenamines R2R3N–C(1)R1C(2)H–NO2(R1= H, Me). The compounds with primary or secondary amino groups (R2 and/or R3= H) exist…
When considering the analysis of chitin and chitosan it must be remembered that there is no definitive ‘standard’ material for either polymer. Thus in many instances analysis is carried out in order to characterise the material rather than to determine whether or not it conforms to a definite structure. In the case of…
A discussion is given of the possible orthogonal and Euclidean transformations which are crystallographic. Especially the symmetry operations are considered which are used for the description of quasi-periodic systems. Since the latter are obtained as intersections of periodic n -dimensional structures with the physic…
X-ray diffraction measurements of thin chiral smectic C (Sc∗) liquid crystals between solid plates coated with rubbed polymer film were performed under an electric field. A variety of local layer structures which depend upon the boundary conditions could be observed, including bookshelf and chevron, and some distorted…
Forage production in the Appalachian Region is limited by soil acidity and nutrient deficiencies including phosphorus. North Carolina phosphate rock (PR), a carbonate substituted fluorapatite, should be reactive in these soils and may be appropriate as a low cost P fertilizer. An experiment was conducted to evaluate t…
Melting experiments with plagioclases were performed in the systems Ab-An, Ab-An-H2O, Qz-Ab-An-H2O, and Qz-Or-Ab-An-H2O-CO2. The experimental products were analysed by electron microprobe, and the kinetics of the reactions were studied qualitatively.Melting of the plagioclase in the system Ab-An (P = 1 atm, T = 1420°C…
Author: Ruth, A. A. et al.; Genre: Journal Article; Issued: 1992; Keywords: ALKANES; VISCOSITY; DENSITY; GLASS-TRANSITION RANGE; TEMPERATURE DEPENDENCE<br/>; Title: Temperature-dependence of viscosity and density of glass-forming alkanes