A statistical analysis of geomechanical data and its effect on rock mass numerical modeling:a case study

Geomechanical data are never sufficient in quantity or adequately precise and accurate for design purposes in mining and civil engineering.The objective of this...     

Novel acrylic pressure-sensitive adhesive (PSA) containing silver particles

Acrylic pressure-sensitive adhesives (PSAs) are generally considered as nonelectrically conductive materials. The electrical conductivity is incorporated into acrylic polymer after blending with electrical conductive additives like silver particles. After the addition of electrically conductive silver filler, the main and typical properties of PSAs such as tack, peel adhesion, and shear strength will decline. This study is the first trial which reveals that the acrylic self-adhesive basis must be synthesized with ameliorated initial performances like high tack and excellent adhesion. Currently, the electrically conductive solvent-borne acrylic PSA containing silver fillers are not commercially available on the market. They are promising materials which can be applied for the manufacturing of diverse technical or medical high performance self-adhesive products, such as broadest line of special electrically conductive sensitive tapes.     

UV-Sensitive polyarylates as photolithographic emulsions

Several UV-sensitive polyarylates based on bisbenzylidenoketones for use as potential pho-tolithographic emulsions were obtained by interfacial polycondensation. The structures of obtained UV-sensitive monomers and polymers were confirmed by infrared, ¹H-NMR, and UV spectroscopies. Mechanical and dielectric properties of the obtained polyarylates (in-cluding dielectric loss factor, dielectric constant, volume and surface resistivity, and dielectric strength) were evaluated. The investigations show that some of the new polymers obtained in this study may find application as photoresists. © 1996 John Wiley & Sons, Inc.     

Editorial—Music Information Retrieval

Increasing availability of music data via Internet evokes demand for efficient search through music files. Users' interests include melody tracking, harmonic structure analysis, timbre identification, and so on. We visualize, in an illustrative example, why content based search is needed for music data and what difficulties must be overcame to build an intelligent music information retrieval system.     

Proton glassy state of Rb1-x(NH4)xH2AsO4

We have presented the first experimental data of the temperature dependence of ε'_c and ε'_c for Rb_1-x (NH₄)_x H₂AsO₄. The results are demonstrated by the presence of a glassy state in Rb_1-x (NH₄)_x H₂AsO₄ for x = 0.31.     

The effect of the gradual thermal decomposition of surface oxygen species on the chemical and catalytic properties of oxidized activated carbon

The physicochemical properties, surface chemical structure and some catalytic properties of a series of carbons prepared by nitric acid oxidation of an activated carbon and subsequent heat treatment under vacuum and mild temperature conditions (423-573 K) were studied. The porous structure characteristics of the partially evacuated samples were estimated from low-temperature nitrogen adsorption data. The thermal analysis and the quantitative determination of surface functional groups by selective neutralization of bases and pH-metric titration were carried out. The dehydration of 2-methylpropan-2-ol was used as a test reaction. While gradual annealing in vacuum alters the surface only slightly, it does differentiate strongly the number and the acidic strength of the surface groups. Progressive heating under mild conditions removes mainly those surface groups that are located in macropores or on the outer surface of the carbon. According to TPD results, the decomposed surface groups are single carboxylic groups, as expected. The decomposition of single, strong carboxylic groups is accompanied by rearrangements of other carboxylic groups with the simultaneous formation of additional cyclic structures like anhydrides, lactones or lactols. Catalytic tests support our previous findings that oxidized carbons have a high dehydration activity. This activity is controlled not only by the number and the strength of acidic groups, but also by their accessibility. There exists an optimum concentration of surface acidic groups above which the activity decreases due to steric restrictions.     

Effect of temperature on sorption isotherms of Brussels sprout

The effect of temperature (0, 20 and 40 degrees C) on the sorptivity of freeze-dried Brussels sprout was studied. It was checked which of the sorption isotherm equations that included temperature was the best to estimate experimental data. The surface area of a monolayer and isosteric heat of sorption was calculated. From the tested equations the Guggenheim-Anderson-de Boer (GAB) and Oswin equations appeared to be the best for describing sorption isotherms of freeze-dried Brussels sprout. The Clausius-Clapeyron equation was found suitable for the calculation of pure isosteric heat of sorption.     

Anion buffering in the internal electrolyte resulting in extended durability of phosphate-selective electrodes

The decomposition of the ionophore uranyl salophene in a polymeric membrane is the main source of the deterioration of phosphate-selective electrodes in time. Due to the efficient buffering of both phosphate and uranyl ions in the internal electrolyte solution, a significant decrease of the rate of decomposition of uranyl salophene in the membrane was observed, improving the lifetime of phosphate-selective electrodes. The most efficient buffering of such ions, resulting in the best sensor durability, was obtained using the internal electrolyte solution containing barium-uranyl phosphate mineral, meta-uranocircite II.     

Ice analog halos

Crystals of sodium fluorosilicate are used to produce easy to set up visual displays of atmospheric halos, including the 22 degrees halo, the Parry arc, and upper tangent arcs. Scattering phase functions for single ice-analog rosettes, including a rough one, and a column aggregate, measured in randomized orientation, are also given. The phase functions show prominent halo features, with the exception of the rough crystal.     

The effect of molybdenum upon blood serum enzymatic ceruloplasmin activity in rats

Experiments were carried out on 61 male and female Wistar rats. Following 21-day intraperitoneal administration of molybdenum (Na₂MoO₄ · 2H₂O), significant differences in the level of blood serum ceruplasmin were noted in female rats depending upon the applied dose of molybdenum. In analogous groups of male rats no statistically significant differences were observed, which might indicate that the effect of molybdenum upon enzymatic ceruplasmin activity is sex-related.The rats on an increased dietary level of 14 ppm molybdenum, of 10.8 ppm copper content and 507 ppm inorganic sulphur, showed decreased blood serum ceruloplasmin activity irrespective of their sex.