Laser Communication Networks

"Most ISOs in the US minimize the total bid cost and then settle the market based on locational marginal prices. Minimizing the total bid cost, however, may not lead to maximizing the social welfare. Studies indicate that for energy only, payment cost minimization (PCM) leads to reduced payments for a given set of bids, and the “hockey-stick” bidding a less likely to occur. Since co-optimization of energy with ancillary services leads to a more efficient allocation, it is important to solve PCM co-optimization while considering transmission capacity constraints for a
comparison with other auction mechanisms. In this paper, PCM is formulated using price definition system-wide constraints. This problem formulation introduces difficulties such as nonlinearity, non-separability and complexity of convex hull. To overcome these difficulties, the nonlinear terms are linearized thereby allowing to be solved by using branch-and-cut. At the same time, the linearization is performed in a way that the “surrogate optimality condition” is satisfied thereby allowing the problem to be solved efficiently."

The article first describes characteristics of major infrastructure projects. Second, it documents a much neglected topic in economics: that ex ante estimates of costs and benefits are often very different from actual ex post costs and benefits. For large infrastructure projects the consequences are cost overruns, benefit shortfalls, and the systematic underestimation of risks. Third, implications for cost–benefit analysis are described, including that such analysis is not to be trusted for major infrastructure projects. Fourth, the article uncovers the causes of this state of affairs in terms of perverse incentives that encourage promoters to underestimate costs and overestimate benefits in the business cases for their projects. But the projects that are made to look best on paper are the projects that amass the highest cost overruns and benefit shortfalls in reality. The article depicts this situation as ‘survival of the unfittest’. Fifth, the article sets out to explain how the problem may be solved, with a view to arriving at more efficient and more democratic projects, and avoiding the scandals that often accompany major infrastructure investments. Finally, the article identifies current trends in major infrastructure development. It is argued that a rapid increase in stimulus spending, combined with more investments in emerging economies, combined with more spending on information technology is catapulting infrastructure investment from the frying pan into the fire.

A novel dual-output six-switch inverter topology is proposed in this paper for independently supplying two three-phase loads. This inverter employs less number of semiconductor devices compared to former dual-output inverters proposed so far in the literature. Reducing the number of switches and hence drive and control circuits results in reduction in total cost and loss and increases the system efficiency and reliability. The new configuration is introduced and carrier-based PWM schemes for its two defined modes of operation (constant frequency and variable frequency modes) are developed. Furthermore, analysis of semiconductor loss is performed and the results are compared with counterpart topologies. Simulation and experimental results will be presented to confirm the theoretical basis.

The choice of working fluid should be a very important consideration as it can affect the overall efficiency of the OTEC cycle. In this paper, an OTEC cycle with regenerator, cooler, tank, expansion valve and static mixer is proposed to compare the performance of randomly selected fluids on the rate of evaporation, turbine work, pump work and system efficiency using the HYSYS software package. Results indicated that for a DOTEC cycle, specific heat depends on the viscosity of the working fluid as well as its evaporator outlet molar density and molecular weight but not its thermal conductivity as displayed by R744.  And for a fixed heating source, wet working fluids with high critical temperatures and heat addition rate possesses a superior turbine work and least pump work as shown by R717. R152a had the highest system efficiency about 0.04% higher than R717 Furthermore, R744 and R717 displayed endothermic enthalpies at the evaporator outlet which means an increase in heat source temperature can directly increase their system efficiencies.

"Biomass co-firing with lignite represents an attractive solution for operating lignite-fired thermal power plants (TPP) with the dual advantage of using local renewable resources and  imultaneously reducing emissions. The subject of this study is technical and environmental investigation of the feasibility of the cofiring of Soma lignite with some dried agricultural residues in the Soma thermal power plant from the exergy analysis perspective, using THERMOFLEX simulation software. The use of biomass cofiring with poor quality coal could allow Turkey to comply with Kyoto commitments while benefiting from using indigenous fuel resources and reducing biomass waste disposal problems. Two technologies are considered; (1) direct cofiring, in which biomass is mixed with lignite in the same mill and fed into the boiler furnace and (2) parallel cofiring method, in which biomass is fired in a separate circulating fluidized bed boiler and produced steam is supplemented into the steam network of the power plant. The investigations reveal that both direct and parallel co-firing of the biomass could result in a significant decrease in fuel consumption, emissions and exergy destruction and a slight increase in the exergy efficiency of the Soma TPP. Olive waste, in particular, has a positive effect on general performance and emissions of the TPP, with fuel consumption, CO2 , SO2
and dust emissions, in direct co-firing dropping by approximately 20, 4, 19 and 18 percent, respectively, and in parallel co-firing by 26, 3, 20 and 25 percent, respectively."

A simple system has been formulated for the operation of wind-driven stand-alone doubly fed induction generators (DFIGs) supplying isolated loads at stator terminals. The stator voltage magnitude and frequency are maintained constant by closed-loop control. The excitation of the rotor is established using a single inverter which is an sinusoidal pulse width modulation (SPWM) inverter supplied through set of batteries. This allows the proposed system to feed continuous power supply to the isolated load via charging/discharging of the batteries depending on excess/deficit power from the wind. The system operates in various modes depending upon the availability of wind and size of the load. All possible modes of operation have been identified and described in the present study. The magnitude and frequency control strategies proposed in this study have been implemented using TMS320LF2407A digital signal processor (DSP) controller and detailed procedure for such implementation is given. The proposed control strategy is free from machine parameter variation and so the co-ordinate transformations, rotor position detection, measurements of rotor currents are not required. Experimental results obtained on a three-phase DFIG together with the closed-loop controller confirm the usefulness of the proposed system and the validity of its analysis.

"http://www.researchmoz.us/global-and-china-laser-projector-industry-2013-market-research-report-report.html

Laser Projector basic information included Laser Projector definition classification application industry chain structure industry overview; international market analysis, China domestic market analysis, Macroeconomic environment and economic situation analysis and influence, Laser Projector industry policy and plan, Laser Projector product specification, manufacturing process, product cost structure etc. then statistics Global and China key manufacturers Laser Projector capacity production cost price profit production value gross margin etc details information, at the same time, statistics these manufacturers Laser Projector products customers application capacity market position company contact information etc company related information, then collect all these manufacturers data and listed Global and China Laser Projector capacity production capacity market share production market share supply demand shortage import export consumption etc data statistics, and then introduced Global and China Laser Projector 2009-2018 capacity production price cost profit production value gross margin etc information. "