Abstract: This paper is to find the influence of thermal stresses on die casting design. Finite Element Analysis (FEA) have been utilized for this purpose. Different parameters such as temperature, and mechanical properties of die material are studied. Temperature transients at different locations of the specimens are measured and used in calibration of finite element model (FEM). The computation of transient stresses is performed by developed FEM. The results showed significant differences in produced thermal stresses for analyzed materials, test parameters, and edge geometries.

Abstract

The high-performance size-exclusion chromatography (HPSEC) and radiochromatography (HPSERC) was used for the identification of radiocesium and radiostrontium interaction with humic acid. It was found that the behavior of humic acid on size-exclusion chromatography is sensitive to the salt concentration and pH of the mobile phase. At lower ionic strength and in acidic region of pH, the Aldrich humic acid exhibited three main fraction within the ranges > 760 kDa, 25-100 kDa and < 5 kDa. Radiocesium was found in the low-molecular fractions (< 1 kDa) of humic acids but radiostrontium interacts preferably with the fractions of humic acid of molecular weight within the range 2-5 kDa. (author) 27 refs.

: This paper describes 29Si, 27Al, 207Pb and 113Cd NMR studies of Pb- and Cd-exchanged LTA zeolites. The 113Cd NMR spectra identify for the first time two different coordination states for Cd2C in hydrated CdLTA, consistent with x-ray single crystal diffraction data for this zeolite. The effects of Cd2C exchange on the 29Si NMR spectra of LTA are also consistent with the structural data. Cd2C exchange perturbs the 27Al NMR spectrum of the zeolite, as does Pb2C exchange. Changes in the 29Si NMR spectra on Pb2C exchange are explained in terms of structural distortion of the framework. 207Pb NMR spectra of Pb2C exchanged LTA show a single broad signal indicating that Pb2C cations are rigidly located in the zeolite at relatively long Pb—O distances in the hydrated zeolites.

Configurable Computer Design for Guidance and Control Algorithms

In this paper mappings of several different algorithms from the fields of operating systems and multimedia are discussed, together with the underlying system architecture. The system architecture is based on a board with four FPGA circuits. For the purpose of this research, a simulator of the system has been developed, and different interconnection networks, memory, and bus architectures have been tested. The results of the simulation, as well as analytical results, are presented.

Abstract: Die ca sting process is one of the widely used processes in the manufacturing area. It has the capability for high production rate s with good strength, high quality part s with complex shape s. Die is the main factor which affect s the cost of this process. Even when the process is semi or fully automated the cost of the die is proportionately high. Commercially available FEA Software (LUSAS) has been u sed. A full Finite Element Analysis was carried out in order to achieve an optimum de sign, and to predict the die life. The analysis has been repeated several time s for different element s to achieve the best possible de sign. Since ca sting is a repetitive manufacturing process, fatigue load was taken into consideration and analysis carried out for a high number of cycle s.

Iron substituted ETS-10 samples with different Fe/Ti ratios were synthesised hydrothermally. The occurrence of a doublet with the isomer shift of octahedral Fe(III) in the Mossbauer spectra.

The effect of humic acid addition on the capacity of inorganic sorbents to sorb radioactive cesium and strontium was studied on montmorillonites in a calcium and potassium form. The Sips isotherm for humic acid sorption and multisite distribution model of ion sorption was found to suit well for the description of mobility of ions as a function of equilibrium humic acid concentration as a single variable at given pH and type of silicate. Complexation of the ions was of minor importance at the conditions investigated. Influence of humic acid on the specific radiocesium interception potential (SRIP) was also evaluated

الوصف

A standard analytical technique for determination of the partial ion exchange capacity of mineral or soil for selective uptake of cesium, the specific radiocesium interception potential (SRIP) is formulated and theoretically discussed. The method is based on the determination of a retained, leached or sorbed fraction of carrier-free cesium-137 in soil contacted with 0.01M KNO ₃ -0.01M Ag thiourea complex solution at the phase ratio solution:sorbent 10 ml:0.1 g. Reliability of the method is discussed in connection of radiocesium carrier and humic substances presence.