Materials Literature
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ABSTRACT Water is desorbed from apples in two stages. The initial stage is characterized by a very fast release of water. The second stage corresponds to low moisture contents and a low rate of desorption. The process can be mathematically modeled in different ways depending on whether or not the true tissue structure…
Abstract The biosynthesis of fatty acids in the diatom Phaeodactylum tricornutum was studied. The diatom was incubated with sodium [1 14 C] acetate and the acids [1‐ 14 C] palmitic, [1‐ 14 C] stearic, [1‐ 14 C] linoleic and [1‐ 14 C] α‐linolenic. The distribution of radioactivity in the products was determined by gas…
The chemical diffusion coefficient was measured for undoped, single‐crystalline NiO at 900° to 1200°C and within an oxygen partial pressure of 10 −5 to 0.21 atm. Electrical conductivity was used to monitor the reequilibration kinetics after the oxygen pressure was suddenly changed over the initially equilibrated NiO c…
[Au9L8]3+(L = PPh3) reacts with L to give the new dication [Au8L8]2+; an X-ray analysis of [Au8(PPh3)8](aliz)2(aliz = alizarinsulphonate) shows that the central gold atom, while still displaying the usual short interactions with all the peripheral metal atoms, is no longer confined in an entirely metallic cage, but is…
1-(5-Amino-5-carboxypentyl)pyridinium chloride (3) and 1-(5-amino-5-carboxypentyl)-3-[1-(5-amino-5-carboxypentyl)-2-piperidyl]pyridinium chloride, anabilysine (4), have been isolated from acid hydrolysates of glutaraldehyde-treated ovalbumin and their structures confirmed by synthesis. It is concluded that the strong…
Abstract Polytetrafluoroethylene (PTFE) was extruded from a capillary rheometer at temperatures between the first‐order transition at 30°C and the melting point. Both PTFE at 50–300°C and various smectic states of certain low‐molecular benzylidene anilines obey the following relationship between the shear stress τ and…
The synthesis of symmetrically as well as unsymmetrically substituted tetraphenyl-21,23-dithiaporphyrins (S2TPP) is described. The reaction of 2,5-dilithiothiophen with substituted benzaldehydes is used for the preparation of substituted 2,5-bis(phenyihydroxymethyl)thiophens. Symmetrically substituted S2TPP molecules…
Both manganese(II) and (III) porphyrins exhibit low-intensity, short-lived luminescence in ethanol solution at 77 K. Manganese(II) porphyrins are stable towards photodecomposition when irradiated in fluid solution but undergo efficient photoreduction in the presence of a good hydrogen donor such as ascorbic acid. Mang…
Before appropriate preventative measures can be chosen to avoid any corrosion problem the latter needs to be anticipated and predictability possibly poses greater difficulties in relation to stress corrosion than many other modes of corrosion related failure. Consequently some recent work on predicting environmental r…
Surface states of nylon 6, polyethylene, and polypropylene are investigated using external photoelectric emission. These polymers seem not to have exact threshold energies. The top edges of the filled surface-states of polymers are located near 4 eV from the vacuum level. From the measurement of electron-irradiated sa…
It is suggested that the ion condensation hypothesis, previously used for polyelectrolyte solutions, also describes the ion binding in lyotropic liquid crystals formed in mixtures of amphiphiles and water. Counterion n.m.r. quadrupole splittings of these systems are shown to be appropriate for testing the ion condensa…
We discuss first the small-angle scattering of neutrons by a homopolymer melt, when each chain is tagged at certain sites by deuteration. We then extend these considerations to block copolymers AB, assuming an AB interaction which is weakly repulsive. Starting from the homogeneous melt, we lower the temperature and de…
Early theoretical predictions that amorphous and liquid polymers should be devoid of significant order down to dimensions commensurate with the diameter of the chain are supported by an extensive body of evidence from X-ray scattering at small and at wide angles, neutron scattering at small and at intermediate angles,…
Abstract A simple method has been suggested for the fractionation of polysuccinimide (PSI); the intrinsic viscosities of fractions were measured and the parameters of the Mark‐Houwink equation were determined. The possibilities of reactions of PSI with primary amines such as histamine, tyramine, tryptamine, mono‐BOC‐e…
A number of esters and other compounds containing a trans-1,4-substituted cyclohexane ring system-have been prepared, and the liquid crystal thermal stabilities of these new mesogens are discussed in relation to those of their analogues containing the 1,4-phenylene ring. The observed effects are discussed in terms of…
[Au9L8]3+(L = PPh3) reacts with L to form [Au8L8]2+ and [AuL2]+; preliminary X-ray structural results are reported for [Au8L8][PF6]2.2CH2Cl2(1).
The reduction of aromatic nitro-compounds by NaBH4 in ethanol in the presence of various transition metal cetylacetonates has been investigated. Copper(II) acetylacetonate was found to be the most effective catalyst for reduction to the corresponding amines. This reaction appears to proceed through a hydride metal com…
The abrasive wear resistance and fracture toughness of the principal types of alloy white cast iron have been determined in laboratory tests. It was found that low-stress abrasion resistance is controlled principally by the hard, dispersed carbide phase, and that the hardness of the matrix is of secondary importance o…
The effect of ordering on the magnetic properties such as magnetostriction, magnetic anisotropy, permeability, and coercive force of 6.5-percent silicon-iron alloy has been studied. The alloys were heat-treated at various temperature, and then quenched into oil. It was found that magnetostriction decreases with the gr…
Massive wound edema after a burn may impair healing and help to convert partial to full-thickness injury. Cold treatment (usually by immersion) has been reported to decrease wound edema and is useful in first-aid treatment of burns. Reliable quantitative data have been lacking and frequently a superficial burn has bee…