OPTIMUM OF PRESSURE RATIOS OF MULTI-STAGE RECIPROCATING COMPRESSOR WITH PRACTICAL INTER-COOLING

The optimum pressure ratio distribution of a multistage reciprocating compressor is presented based on the assumption, i.e. the inter stage cooling is perfect and there are no pressure losses. The optimization of the two or three stage pressure ratio is analyzed in two cases of constant heat transfer rate for the inter cooler or constant inter stage inlet temperature, based on the minimum of the sum of theoretical compression power at each stage about a multi stage reciprocating compressor. Furthermore, with an example of two stage compressor the influence on the sum of the power of each stage is analyzed when practical pressure ratio deviates from the optimum value. It is obtained that under different cooling conditions the optimum pressure ratio distribution of the multi stage compression is various, and the change of the optimum pressure ratio within a small range has little influence on the sum of the power each stage. For the two stage compression, this range can be represented as ε 1=(0 96～1 06)ε 1j .

A Frame Work of Multistage Decision Making

This research has objective to analyze some tools which are used to support decision maker to make a decision in multi stage and systematic way. And also in making decision, there are a qualitative type and quantitative type. In order to get an optimum decision making, the decision maker needs systematic way. There is the frame work which is based on combination of some existing methods and challenges emerging in organizational activities, including social organizations as well as business organisations. To formulate the framework, this research conducted focus group discussion consisting of some organizational managers as participants. There are five components of proposed frame work： （1） Criteria Identification through Focus Group Discussion （FGD）; （2） Criteria Selection; （3） Focus Group for Criteria Verification; （4） Multicriteria Decision Making based Analytic Hierarchy Process （AHP）; and （5） Impact Analysis. This research resulted in an effective approach of decision making which allows decision maker to have objective and rational reason in each step of its decision-making process. Strength of the proposed framework is to provide rational and objective approach in group decision making. However, it takes longer time to conduct decision making due to more steps and participants involved. As a conclusion, the proposed research has been successful in establishing a multi stage and rational decision-making process.

基于多级串行干扰和并行干扰消除的多用户检测器设计

为了采用能够进行多用户检测的先进基站接收机来提高宽带码分多址上行链路中IP电话的容量和覆盖,该文提出了采用多级串行干扰消除检测器或并行干扰消除检测器作为MUD的实现.在检测另一个用户信号之前,SIC或PIC从接收信号中消除来自于接收信号的许多临时检测到的用户信号,临时检测的用户信号可以基于解调数据或解码数据和基于硬判决值或软判决值再生;为了避免联合检测的复杂性,提出了采用时分复用将用户组及时分离,以便MUD能够集中在少量重叠信号上.基于一个2级SIC或PIC过程的仿真结果表明,当每个TTI有5个活跃VoIP用户时,对于实现10%的BLER,每个用户所需功率可以减少高达3dB,当有更多的活跃用户时,通过MUD所能实现的功率减少更多,这意味着系统具有了更高的容量、更好的覆盖,并提高了VoIP用户的通话时间.

Diamonds Discovered from High–Cr Podiform Chromitites of Bulqiza,Eastern Mirdita Ophiolite,Albania

Various combinations of diamond, moissanite, zircon, corundum, rutile and titanitehave been recovered from the Bulqiza chromitites. More than 10 grains of diamond have been recovered, most of which are pale yellow to reddish–orange to colorless. The grains are all 100–300 μm in size and mostly anhedral, but with a range of morphologies including elongated, octahedral and subhedral varieties. Their identification was confirmed by a characteristic shift in the Raman spectra between 1325 cm-1 and 1333 cm-1, mostly at 1331.51 cm-1 or 1326.96 cm-1. This investigation extends the occurrence of diamond and moissanite to the Bulqiza chromitites in the Eastern Mirdita Ophiolite. Integration of the mineralogical, petrological and geochemical data of the Bulqiza chromitites suggests their multi–stage formation. Magnesiochromite grains and perhaps small bodies of chromitite formed at various depths in the upper mantle, and encapsulated the ultra–high pressure, highly reduced and crustal minerals. Some oceanic crustal slabs containing the magnesiochromite and their inclusion were later trapped in suprasubduction zones, where they were modified by tholeiitic and boninitic arc magmas, thus changing the magnesiochromite compositions and depositing chromitite ores in melt channels.

Incident indicators for freeway traffic flow models

Developed in this paper is a traffic flow model parametrised to describe abnormal traffic behaviour.In large traffic networks,the immediate detection and categorisation of traffic incidents/accidents is of capital importance to avoid breakdowns,further accidents.First,this claims for traffic flow models capable to capture abnormal traffic condition like accidents.Second,by means of proper real-time estimation technique,observing accident related parameters,one may even categorize the severity of accidents.Hence,in this paper,we suggest to modify the nominal Aw-Rascle(AR)traffic model by a proper incident related parametrisation.The proposed Incident Traffic Flow(ITF)model is defined by introducing the incident parameters modifying the anticipation and the dynamic speed relaxation terms in the speed equation of the AR model.These modifications are proven to have physical meaning.Furthermore,the characteristic properties of the ITF model is discussed in the paper.A multi stage numerical scheme is suggested to discretise in space and time the resulting non-homogeneous system of PDEs.The resulting systems of ODE is then combined with receding horizon estimation methods to reconstruct the incident parameters.Finally,the viability of the suggested incident parametrisation is validated in a simulation environment.