Graft-copolymerization of starch with acrylamide,II. Thermal behaviour of graft copolymers

Thermal behaviour of starch-graft-polyacrylamide (S-g-PAM) copolymers was evaluated. Grafting of polyacrylamide onto starch lowers the initial decomposition temperature. However, the over-all stability as assessed by the shape of thermogravimetric curve and integral procedural decomposition temperature increased with an increase in % graft-on.     

Effect of sodium monofluorophosphate treatment on microstructure and frost salt scaling durability of slag cement paste

Sodium-monofluorophosphate (Na-MFP) is currently in use as a surface applied corrosion inhibitor in the concrete industry. Its basic mechanism is to protect the passive layer of the reinforcement steel against disruption due to carbonation. Carbonation is known as the most detrimental environmental effect on blast furnace slag cement (BFSC) concrete with respect to frost salt scaling. In this paper the effect of Na-MFP on the microstructure and frost salt scaling resistance of carbonated BFSC paste is presented. The results of electron microscopy, mercury intrusion porosimetry (MIP) and X-ray diffraction (XRD) are discussed. It is found that the treatment modifies the microstructure and improves the resistance of carbonated BFSC paste against frost salt attack.     

Water-saving strategies for irrigation agriculture in Saudi Arabia

Agriculture policy changes in Saudi Arabia are investigated by water footprint (WF) assessment. WF is calculated with the model SPARE:WATER for 3758 irrigated sites. The WF of agriculture areas (WF_area, km³ yr^?1) has decreased (–17%) since the year 2000 to 13.84 km³ yr^?1 (2011), which is mainly caused by the reduction of cropland by –33%. Nevertheless, water consumption per field has increased about 16%, which can be attributed to the cultivation of fodder crops (+12%). A scenario analysis revealed that a shifting cropping pattern towards less fodder crops reduces WF_area by –15%, and implementing improved irrigation technology leads to a combined reduction of up to 32%     

Effect of alkaline earth metal or iron contaminants on properties of viscose

Conclusions The effect of salts of alkaline earth metals and iron on the physico-chemical indices of viscose — viscosity, ripeness, and filterability — has been investigated.In amounts which exceed the content allowed by the All-Union State Standard in viscose by a factor of 3–4, calcium and magnesium ions do not cause a significant impairment in the physico-chemical indices of the viscose.Even at a content of 28 mg/liter, the presence of trivalent iron salts in a viscose causes a sharp impairment in its filterability, especially on prolonged ripening.Strict control of the trivalent iron content of viscose during the process of preparing it for spinning is necessary.Siberian Technological Institute. Translated from Kimicheskie Volokna, No. 2, pp. 17–18, March–April, 1987.     

Economic aspects of membrane processes

Care must be exercised, in predicting operating costs for membrane desalination systems for electricity, labor, chemicals, etc. The assumptions made in establishing unit costs can greatly affect the predicted operating cost and hence the ultimate investment decision. The use of data estimating the quantities of chemicals, power, etc., expected to be used per unit of production can assist in predicting costs, as then site-specific cost data can be used. The fact that 0.2 pounds of acid per kgal of permeate is required in a Florida RO plant is more useful for predicting operating costs of an RO plant on the Island of Anegata than is the fact that acid costs at the Florida plant are $0.03/kgal of water produced. Data based on units rather than costs are presented for seven RO facilities and one ED facility in this paper for use in this type of analysis.     

A model of density of states in amorphous Si, C and SiC from time-of-flight measurement

The temperature dependence of the electron drift mobility in glow-discharged undoped hydrogenated amorphous silicon, carbon and silicon carbide films with stoichiometric compositional (a-Si_0.5C_0.5:H) has been measured by the time-of-flight method. All films displayed the same behaviour of the transient current and dispersion parameters, which can be explained by assuming a gaussian distribution of tail states near the conduction band. The results obtained results corroborated the common nature and degree of disorder of the conduction band tail in all four-coordinated amorphous semiconductors.     

Investigation of the heat treatment processes of resin-bonded refractories in an atmosphere consisting of the products of sublimation and decomposition of the binder

Conclusions Heat treatment of the resin-bonded refractories in an atmosphere consisting of the products of sublimation and decomposition of the binder leads to a significant improvement in the properties of the specimens (in particular, in the coked condition). The increase in the content of the residual carbon, the mechanical strength of the specimens, and their hydration resistance are determined by the heat treatment temperature. The highest levels of the physical and the technological properties are obtained after heat treating the specimens in the 400–600°C range. In this case, the most significant effect is observed in the lime-periclase refractories and the minimum effect is obtained in the resin-periclase refractories.The increased hydration resistance of the resin-bonded refractories containing free calcium oxide (the lime-periclase and the periclase-lime refractories) owes mainly to fixing up of CaO during the heat treatment process and to the formation of the protective calcium carbonate films at the surface of the fired dolomite grains.Translated from Ogneupory, No. 2, pp. 10–13, February, 1992.     

Corundum hydraulically hardening rammed compounds with a reduced grain size

Conclusions The production and use of rammed hydraulically hardening corundum compounds with different maximum grain sizes (from 1 to 7 mm) permits intermediate repairs of the linings of ladles of a steel ladle treatment unit, increasing their life.It is possible to determine the quantity of binder for obtaining the maximum strength by calculation by use of the coefficient of optimization, which is the portion of binder required per unit of specific surface of the mixture of filler grains. For the corundum hydraulically hardening compounds the optimum value of this coefficient is 0.8–1.2.Translated from Ogneupory, No. 2, pp. 40–43, February, 1987.     

Automated procedure to determine the thermodynamic stability of a material and the range of chemical potentials necessary for its formation relative to competing phases and compounds

We present a simple and fast algorithm to test the thermodynamic stability and determine the necessary chemical environment for the production of a multiternary material, relative to competing phases and compounds formed from the constituent elements. If the material is found to be stable, the region of stability, in terms of the constituent elemental chemical potentials, is determined from the intersection points of hypersurfaces in an (n−1)$(n-1)$-dimensional chemical potential space, where n$n$ is the number of atomic species in the material. The input required is the free energy of formation of the material itself, and that of all competing phases. Output consists of the result of the test of stability, the intersection points in the chemical potential space and the competing phase to which they relate, and, for two- and three-dimensional spaces, a file which may be used for visualization of the stability region. We specify the use of the program by applying it both to a ternary system and to a quaternary system. The algorithm automates essential analysis of the thermodynamic stability of a material. This analysis consists of a process which is lengthy for ternary materials, and becomes much more complicated when studying materials of four or more constituent elements, which have become of increased interest in recent years for technological applications such as energy harvesting and optoelectronics. The algorithm will therefore be of great benefit to the theoretical and computational study of such materials.     

Utility of stereoscopic displays for indirect-vision driving and robot teleoperation

The effectiveness of an active shutter-glasses stereoscopic display (SD) and a passive polarised SD was evaluated in a live robot-teleoperation task and a simulated indirect-vision driving task in various terrains. Overall, participants completed their tasks significantly faster with the SDs in three-dimensional (3D) mode than with the SDs in the baseline 2D mode. They also navigated more accurately with the SDs in 3D mode. When the effectiveness of the two types of SDs was examined separately, results showed that the active shutter-glasses SD resulted in faster responses and task completion times than the passive polarised SD, though most of the differences failed to reach statistical significance. Perceived workload when interacting with the two SD systems did not differ significantly between the active versus passive display types or between the 3D and 2D modes of operation; however, participants reported more severe discomfort after interacting with the passive polarised SD.