Nuclear data sheets for A = 140

Nuclear structure data for mass 140 nuclei are compiled and adopted level and gamma-ray properties are presented. The adopted values are based on all data received before August 1973.     

Nuclear data sheets for A = 136

The experimental nuclear structure data available through August 1978 have been reviewed. A summary of information obtained in various reaction and decay experiments is presented, together with adopted level schemes.     

Experience in managing a unit for continuous preliminary dearation of viscose

Conclusions Tests of an experimental specimen of a unit for continuous preliminary deaeration have been carried out.The unit assures practically complete removal of air from viscose at the design output.The deaerator can be used to modernize existing units for final deaeration in technical re-equipment of operating plants.Translated from Khimicheskie Volokna, No. 2, pp. 50–51, March–April, 1987.     

Spatial Analysis of Single Allocation Hub Location Problems

Hubs are special facilities that serve as switching, transshipment and sorting nodes in many-to-many distribution systems. Flow is consolidated at hubs to exploit economies of scale and to reduce transportation costs between hubs. In this article, we first identify general features of optimal hub locations for single allocation hub location problems based on only the fundamental problem data (demand for travel and spatial locations). We then exploit this knowledge to develop a straightforward heuristic methodology based on spatial proximity of nodes, dispersion and measures of node importance to delineate subsets of nodes likely to contain optimal hubs. We then develop constraints for these subsets for use in mathematical programming formulations to solve hub location problems. Our methodology can also help narrow an organization’s focus to concentrate on more detailed and qualitative analyses of promising potential hub locations. Results document the value of including both demand magnitude and centrality in measuring node importance and the relevant tradeoffs in solution quality and time.     

Performance enhancement of cascaded qZS-HB based renewable energy system using Model Predictive Control

This paper presents a multi-objective Model Predictive Control (MPC) for a grid connected 2-cell 5-level quasi Z-Source (qZS) Cascaded H-Bridge (CHB) inverter. The main contribution of the proposed control approach is the design of a multi-constraint cost function to achieve multi-objective MPC strategy dealing with the complex nature of the presented qZS-CHB topology. The designed cost function takes into account three control objectives, which are the minimization of the grid current, input current, and capacitors' voltages tracking errors. The best performance scenario is realized through the fine tuning of the constraints' weighting factors based on the grid current's error minimization and the reduction of the double-line frequency ripples on the input current. As a result, the proposed scheme achieves high-quality tracking of the encompassed state variables with the elimination of the double-line frequency power flow through the qZS inductors leading to the reduction of the hysteresis losses and the increase of the overall system efficiency. The performance of the proposed MPC strategy has been investigated and compared to the state of art PI controller. Theoretical analysis and implementation results are given to show that the proposed scheme is suitable for all system configurations and has good performances even during disturbances.     

An original observer design for reduced sensor control of Packed U Cells based renewable energy system

This paper presents an original Switched Observer (SO) for reduced-sensor control of a grid-connected Packed U Cells (PUC) multilevel inverter. The proposed SO performance is evaluated using a single-phase 7-level PUC inverter connected to the grid through filtering inductor. Based on the actual grid current, the proposed SO estimates accurately the PUC capacitor voltage, which is fed to the Model Predictive Control (MPC) algorithm while making use of a hybrid model considering both discrete and continuous variables. For real-time application, necessary conditions are given to guarantee the practical stability of the proposed SO under system parameters and input voltage variations according to the selected switching pattern. Theoretical analysis and simulation investigations are conducted to prove that the proposed SO-MPC scheme is stable in closed-loop for all system configurations and has good performances even during various disturbances (load change, parameters mismatch, and input voltage variation).     

Production of tungsten boride from CaWO4 by self-propagating high-temperature synthesis followed by HCl leaching

In this study, the conditions of producing tungsten boride powder from calcium tungstate (CaWO₄) by self-propagating high-temperature synthesis (SHS) followed by HCl leaching techniques were investigated. In the first stage of the experimental study, the SHS products consisting of borides and other compounds were obtained starting with different initial molar ratios of CaWO₄, Mg and B₂O₃. It was found that increasing B₂O₃ content in the initial mixture resulted in an increase of W₂B₅/WB ratio along with Mg₃B₂O₆ in the SHS product. In the second step, Mg and Ca containing byproducts (i.e. MgO, Mg₃B₂O₆ and Ca₃B₂O₆) found in the SHS product were leached out by using aqueous HCl solution to obtain a clean tungsten boride product. The effects of particle size, temperature, time, acid concentration and solid/liquid ratio were selected as leaching parameters. The acid leaching experiments of the SHS product synthesized at 1:8:2.5 initial molar ratio of CaWO₄:Mg:B₂O₃ showed that optimum leaching conditions could be achieved by using 2.85 M HCl at 1/10 S/L ratio and the temperature of 80 °C for 60 min.     

"Tandir": an old and well known cause of burn injury in the Middle East

This study was conducted to determine the effect of acarbose on serum concentrations of digoxin in healthy male volunteers. A randomized crossover design with three phases was used. In phase 1 participants received 0.5 mg of digoxin alone. In phase 2 they received 0.5 mg of digoxin 0.5 hours after a 200-mg dose of acarbose. In phase 3 they received 100 mg of acarbose 0.5 hours before each meal three times daily for 3 days. On the fourth day, they received 0.5 mg of digoxin 0.5 hours after a 100-mg dose of acarbose. Area under the concentration-time curve (AUC0-48) and mean maximum concentration (Cmax) were significantly lower and tmax significantly increased in phases 2 and 3 compared with phase 1. These results indicate that the absorption of digoxin is reduced by administration of acarbose, and that one of the major mechanisms of this interaction may be due to the pharmacodynamics of acarbose.