Materials Literature
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Abstract A model and a simple measurement technique for time of encapsulation have been developed to study the microencapsulation of butachlor in polyurea shell by means of interfacial polymerization. The model is based on diffusion of the hydrophilic monomer through the polymeric shell with an interfacial reaction at…
The southwestern Indian paintbrush, Castilleja linariaefolia, yielded extracts that displayed in vivo activity against murine P-388 (PS) lymphocytic leukemia. Separation guided by PS cell line inhibition led to isolation of cytotoxic compounds that were identified as the known glycosides acteoside [1] (ED50 2.6 microg…
Abstract Thyme and cumin essential oils were used in the present study in an attempt to prevent butter deterioration during storage at room temperature. Butter oxidation and lipolysis were followed by measuring the acid, peroxide and TBA values. Lipolytic activity and total microbial and lipolytic bacterial counts wer…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolten salt synthesis of low-dimensional ternary chalcogenides. Novel structure types in the K/Hg/Q system (Q = S, Se)Mercouri G. Kanatzidis and Younbong ParkCite this: Chem. Mater. 1990, 2, 2, 99–101Publication Date (Print):March 1, 1990Publication History Published online1…
The electrical properties of three ferrites of composition (Ni 0.36 Zn 0.64 ) 1– x Fe 2+ x O 4 , x =−0.03, 0, 0.13, were investigated by impedance spectroscopy. The observed impedance responses corresponded to that of a highly resistive grain‐boundary component in series with a less resistive bulk component. Bulk resi…
SUMMARY The effects of liming‐induced pH changes on surface charge were studied with four acid Fijian soils. All the soils possessed both positive and negative charge. Much of this charge was pH‐dependent, but some negative charge was present at pH values as low as 4.0 and small quantities of positive charge were dete…
Abstract Primary nucleation is in general heterogeneous in polymer crystallization. In unseeded polymers, the crystallization originates from a very small concentration (<0.1 percent) of unknown submicroscopic heterogeneous nuclei. Only in three cases have the nucleation mechanisms been identified with precision. T…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCharacterization of hake (Merluccius merluccius L.) and trout (Salmo irideus Gibb) collagenPilar Montero, Javier Borderias, Javier Turnay, and Maria Antonia LeyzarbeCite this: J. Agric. Food Chem. 1990, 38, 3, 604–609Publication Date (Print):March 1, 1990Publication History…
The structures of poly(p-hydroxybenzoic acid) (PHBA) at the two high-temperature phase transitions (ca. 340 and 430 °C) have been investigated by X-ray powder diffraction methods (X-ray tube focusing and synchrotron parallel beam), chain conformation/packing models, and dielectric measurements. The structure of PHBA b…
A successful design of a 25 hp permanent-magnet synchronous motor using SmCo/sub 5/ and NdBFe magnets is presented. Expressions to predict the motor run-up and terminal performance are given. The rotor was tested for the straight interior rotor magnet arrangement. A record efficiency of over 94% was obtained at full l…
Abstract The dehydration of gypsum CaSO 4 .2H 2 O has been studied, at negligible water vapour pressure, by in situ infrared (IR) spectroscopy and by thermogravimetry to determine whether intermediate phases (CaSO 4 . n H 2 O) exist, other than the hemihydrate with n =0.5, and also to compare the mechanism of the dehy…
Slow strain rate testing (SSRT) was initially developed as a rapid, ad hoc laboratory method for assessing the propensity for metals and environments to promote stress corrosion cracking. It is now clear, however, that there are good theoretical reasons why strain rate, as opposed to stress per se, will often be the c…
Abstract By using an automated low‐frequency apparatus, dynamic mechanical experiments are performed on bulk‐crystallized high‐density polyethylene in the temperature range of the α relaxation. In order to characterize the key morphological features governing the presence of multiple α relaxations, we have developed a…
Climate strongly influences soil clay mineralogy and bulk chemical composition. In humid climates chemical weathering is at its most intense and virtually all ‘primary’ bedrock minerals suffer complete breakdown. They are replaced by authigenic hydrated oxides of Fe and Al together with halloysite and kaolinite in dee…
Low molecular weight liquid crystals with in‐build charge transfer (CT) properties have been generated from both liquid crystalline (LC) and non‐LC disc‐like compounds by doping these electron rich species with electron acceptors e.g. TNF. The influence of CT interactions on the columnar phases formed are assessed and…
The influence of R ‐curve behavior of ceramics on the strength degradation associated with thermal shock is explored. Of particular significance for this interdependence is the observed nonlinear stress‐strain behavior of materials that exhibit minimal strength degradation under severe thermal shock conditions. These…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPoly(aryl ether phenylquinoxalines)James L. Hedrick and Jeff W. LabadieCite this: Macromolecules 1990, 23, 6, 1561–1568Publication Date (Print):March 1, 1990Publication History Published online1 May 2002Published inissue 1 March 1990https://pubs.acs.org/doi/10.1021/ma00208a0…
The Landau model of Slonczewski and Thomas (1970) for the improper ferroelastic ${\mathit{O}}_{\mathit{h}}^{1}$-${\mathit{D}}_{4\mathit{h}}^{18}$ phase transition in perovskite-structure compounds has been extended by including spatial gradient terms of the three-component primary order parameter (OP) and applied to c…
A new formalism for use in atomistic simulations to calculate the full local elastic-constant tensor in terms of local stresses and strains is presented. Results of simulations on a high-angle (001) twist grain boundary are illustrated, using both a Lennard–Jones potential for Cu and an embedded-atom potential for Au.…
Abstract A study was conducted to determine the influence of organic matter on the solubility of Al in organic soil horizons from different geographic regions. Results showed that the equilibrium solubility of Al was dependent on solution pH and the degree to which the soil organic matter was saturated with Al. Plots…