Optimization of association procedure in WiMAX networks with relay stations

When a MS enters to the WiMAX network, a network entry procedure has to be performed. The aim of procedure is twofold. Firstly, several connections between the MS and BS are created, i.e. basic, primary and secondary management connections to control data transmissions. Secondly, the MS is admitted into the network. According to the IEEE 802.16 standard, a MS always tries to associate to BS with the highest received signal quality. This method is suitable as long as the MS is directly connected to the network via BS. However by introducing relay stations to the WiMAX architecture, the MS entry procedure needs to be modified. Mainly, the point of attachment influences the network performance. This paper proposes an optimized association procedure which takes into account the use of relays stations in the network. The obtained results show improvement of system performance.     

Costs and Benefits of Smart Grids on Liberalized Markets

The discussion about smart grid(SG) implementation is mostly focused on pilot projects.These projects are necessary for mapping of particular technical devices of advanced metering management(AMM) which is needed for successful SG and whole functional SG system operation.According to our opinion,for the next step of SG implementation,the participation of effective market design would be quite necessary.In other words,pilot project which is operated regardless to the market conditions and special SG tariff is incomplete and could be irrelevant for further evaluation of feasibility.With regard to above mentioned facts,the detailed cost-benefit-analysis(CBA) is needed to establish the correct methodology for evaluation of SG implementation effectiveness.Related aspects are mentioned and discussed in this paper,in which the particular cost and benefits as well as feedback that occurs as the reaction on implementation are summarized and quantified.     

便携式电池供电医疗设备使用钽电容的考量因素

背景介绍便携式电池供电医疗设备的种类繁多,而能够可靠地为这些设备供电的充电器控制电路也有多种选择。精心选择如钽电容这样的无源元件,可以提升便携式设备内充电器控制和储能系统的整体性能。便携式电池供电医疗设备的供电既可以使用一次性电池,也可以使用用电池充电器充电的后备可充电电池。对医疗设备便携性和易用性的需求已经催生了充电控制电路的多项改良。     

The Liquidus Temperature of Nuclear Waste Glasses: An International Round-Robin Study

Eight institutions from four countries participated in a round-robin study to determine the precision and bias of a liquidus temperature (T_L) procedure for waste glasses being adopted by ASTM International as ASTM C 1720-11. The participants of the round-robin study were asked to measure three different glasses with one or a combination of the following T_L measurement methods: a gradient temperature (GT) method, a uniform temperature (UT) method, and/or a crystal fraction extrapolation (CF) method. The T_L values reported by different institutions are generally consistent. The precision of T_L measurements with each method was evaluated and is presented herein. The round-robin glasses were all previously studied at Pacific Northwest National Laboratory and included ARG-1 (Glass A), Zr-9 (Glass B), and AmCm2-19 (Glass C), with measured T_L values spanning the temperature range of 960–1240°C. A precision (i.e., standard deviation) for T_L has been obtained from the data, even though the data were not acquired for all three glasses using all three methods from each participating organization. Also, the article provides a brief overview and the importance of the T_L measurement.     

Hydrocracking of petroleum vacuum distillate containing rapeseed oil: Evaluation of diesel fuel

Hydrocracking of pure petroleum vacuum distillate and the same fraction containing 5 wt.% of rapeseed oil was carried out at 400 and 420 °C and under a hydrogen pressure of 18 MPa over commercial Ni-Mo catalyst. Reaction products were separated by distillation into kerosene, gas oil and the residue. Fuel properties of fractions suitable for diesel production were evaluated (gas oils and remixed blends of kerosene and gas oil). Gas oils obtained from co-processing showed very good fuel properties as the remixed distillates did. Gas oil obtained from co-processing at 420 °C showed also reasonable key low-temperature properties (cloud point: −23 °C, CFPP: −24 °C) similar to those of gas oil obtained from pure petroleum raw material processing.     

Fuel properties of hydroprocessed rapeseed oil

This paper deals with the hydroprocessing of rapeseed oil as a source of hydrocarbon-based biodiesel. Rapeseed oil was hydroprocessed in a laboratory flow reactor under four combinations of reaction conditions at temperatures 310 and 360 °C and under hydrogen pressure of 7 and 15 MPa. A commercial hydrotreating Ni-Mo/alumina catalyst was used. Reaction products contained mostly n-heptadecane and n-octadecane accompanied by low concentrations of other n-alkanes and i-alkanes. Reaction product obtained at 360 °C and 7 MPa was blended into mineral diesel fuel in several concentration levels ranging from 5 to 30 wt.%. It was found, that most of the standard parameters were similar to or better than those of pure mineral diesel. On the other hand, low-temperature properties were worse, even after addition of high concentrations of flow improvers.     

The digital agenda of virtual currencies: Can BitCoin become a global currency?

This paper identifies and analyzes BitCoin features which may facilitate BitCoin to become a global currency, as well as characteristics which may impede the use of BitCoin as a medium of exchange, a unit of account and a store of value, and compares BitCoin with standard currencies with respect to the main functions of money. Among all analyzed BitCoin features, the extreme price volatility stands out most clearly compared to standard currencies. In order to understand the reasons for such extreme price volatility, we attempt to identify drivers of BitCoin price formation and estimate their importance econometrically. We apply time-series analytical mechanisms to daily data for the 2009–2014 period. Our estimation results suggest that BitCoin attractiveness indicators are the strongest drivers of BitCoin price followed by market forces. In contrast, macro-financial developments do not determine BitCoin price in the long-run. Our findings suggest that as long as BitCoin price will be mainly driven by speculative investments, BitCoin will not be able to compete with standard currencies.