Design of horizontal shear strain instrument for co-estimation of soil stress-strain

This study aimed to design and fabricate the horizontal shear strain transducer (HST) for measuring the soil strain under the agricultural machinery traffic by using a rotary potentiometer which was an angular strain change detector. The angular movable mechanism was calibrated and evaluated the characteristics of the instrument in the laboratory, and found that the non-linearity and the hysteresis were 4.56 and 4.42%, respectively. Furthermore, the strain measurement device was buried in the field to compare the shear strain at varying tractor velocities (5, 6.5 and 8 km/h). For all vehicle speed at the first passage, the shear strain and soil bulk density obviously increased, whereas the final moisture content decreased; as a result, the lower velocity caused higher shear strain.

Penentuan Parameter Rangkak pada Bentonit sebagai Bahan Penyangga (Buffer Material) dengan Uji Geser Langsung

A preliminary research to investigate the creep behavior of bentonite as buffer material in a high-level nuclear or radioactive waste disposal hole as bentonite needs to maintain the stability of the waste canister for a long time, to avoid the displacement caused by the weight of the canister itself and the thermal, hydrological, mechanical and chemical (THM-C) processes of the near filed. The increase of bentonite time-dependent strain or creep needs to be taken into account for the safety of the disposal hole. The creep parameters obtained from the angular strain rate equation, through stress-controlled direct shear test using compacted SPV200 bentonite samples. The test results show an increase in angular strain rate with increasing of the applied stress.

THE EXPERIMENTAL ANALYSIS OF CAPTIVE ASSEMBLIES OF THE PANEL SYSTEM

The increase in the number of storeys is impossible without deviation from standard projects, where the structure of assemblies is not designed for buildings that have more than 12 storeys. That’s why it’s necessary to strengthen assemblies. For that purpose the testing of assemblies of the panel system, which is unique in modern textbooks on design, is performed. The paper presents the results of tests conducted at the plant ZHBI-Vostok of Chelyabinsk. The strength and stress-strain performance of an external horizontal assembly in two different versions (with slab-wall junction and without junction) is evaluated. As a result of experimental data processing, the effect of force eccentricity on the stress condition of assemblies is determined. This influence should be taken into consideration in case of hand calculations on assemblies. The axial and angular strain before the failure of assembly samples and the strength reserve of studied structures are specified.

Étude théorique (AM1) de l'affinité protonique des polyéthers cycliques (éthers couronnes) et non cycliques (glymes)

Semi-empirical calculations at the AM1 level have been used to study the proton affinity (PA) of polyether compounds (dioxane, glymes, and crown ethers). The calculated values, although systematically lower than the experimental ones, are linearly correlated with eight experimental PA's (r = 0.993). Taking into account the considerable conformational changes that take place upon protonation, the result is highly satisfactory and provides an estimate of proton affinity for 9-ether-crown-3 (206.5 kcal mol−1) and glyme-5 (231.1 kcal mol−1). Moreover, this work provides a rationale for the fact that, for the same number of oxygen atoms, glymes are more basic than crown ethers. For the crown ethers, the proton affinity depends on angular strain in the base and on intramolecular hydrogen bonds in the cation. Key words: protonation, reactivity, glymes, crown ethers, coordination.

Influence of solvents on electrochemical reduction potentials of chlorosilanes

The reduction potentials of 1,1-dichloro- and 1-chloro-1-methylsilacyclobutane and their acyclic analogues were measured by cyclic voltammetry in the medium of anisole and dimethylformamide. The obtained values which reflect the simultaneous effect of angular strain and possible interactions of the depolarizer with the solvent were correlated with the result of quantum chemical calculations.