Loss Analysis in the Trackside RF Chain of a Radio-Based CBTC System

2017 ◽  
Author(s):  
Arash Aziminejad ◽  
Gabriel Epelbaum
Keyword(s):  
Measurement Data ◽  
Antenna System ◽  
Optimized Design ◽  
Transmission Network ◽  
Loss Analysis ◽  
Rf Systems ◽  
Train Control ◽  
Multi Stage ◽  
Rf Transmission ◽  
Insertion Losses

A key assumption in the process of optimized design of RF systems is the efficient transfer of power from the transmitter source to the load (i.e., the end antenna). Unless the transmitter is located directly next to the load, a transmission circuit comprised of multiple cascaded or forked segments connects one to the other. An example of such transmission network is the RF transmission chain of the Communication-Based Train Control (CBTC) trackside antenna system. The system design requirement and validation process necessitates development of means for realistic evaluation and analysis of the reflection and insertion loss values offered by the trackside RF chains of a radio-based CBTC system. The aim of this research is to present a comparative study of three different models developed to quantitatively assess reflection and insertion losses in a general multi-stage RF transmission network. To provide a more realistic and credible assessment, the comparison has been further substantiated with measurement data.

Assessment of the Fatigue Life of a PWR Surge Line Including the Effect of Coolant Environment

2009 ◽  
Author(s):  
Gu¨nter Ko¨nig ◽  
Jaroslav Bartonicek ◽  
Horst Rothenho¨fer
Keyword(s):  
Boundary Conditions ◽  
Power Plants ◽  
Measurement Data ◽  
Real Life ◽  
Actual State ◽  
Optimized Design ◽  
Design Phase ◽  
Damage Mechanisms ◽  
Piping Systems ◽  
Surge Line

In Germany, the integrity concept is applied to important piping systems in most of the nuclear power plants. Regarding the framework of this concept, those damage mechanisms that cannot be controlled by analysis have to be excluded using appropriate measures. In most of the cases, these damage mechanisms are a result of local effects (like loads, medium, material characteristics) that cannot be determined exactly in advance and thus cannot be controlled by analysis, reliably. Examples are strain induced corrosion (LCF area) and corrosion fatigue (HCF area). For cases like these and given medium, suitable materials have to be chosen in combination with optimized design, appropriate manufacturing procedures (incl. welding), construction and operation. The loads and the water chemistry in operation have to be monitored and the effectiveness of the measures has to be verified, regularly, taking into account the actual state of knowledge. Regarding these boundary conditions the fatigue evaluations that have been performed until today seem to be sufficient, as experience shows with piping systems where this procedure has been applied. There are usually no significant failures (indication of failures); failures detected have been attributed to violation of the boundary conditions. With this background, there seems to be no need to change this procedure to safeguard the effect of environment. In this paper, the measures to guarantee integrity in design and operation state are discussed, first. Using the example of a surge line and the comprehensive monitoring results of this system the evaluation of fatigue usage and the assessment of the effect of coolant environment is discussed with reference to the ANL approach. Where the ANL approach is meant to be applied only in the design phase of a new reactor its relevance for the operation phase is cross-checked with real life measurement data. The conclusion summarizes where the effect of coolant environment has to be taken into account and gives advice how to find realistic transients for the design phase of new reactors.

Unsteady Aerodynamics of Low-Pressure Steam Turbines Operating Under Low Volume Flow

2013 ◽  
Author(s):  
Benjamin Megerle ◽  
Timothy Stephen Rice ◽  
Ivan McBean ◽  
Peter Ott
Keyword(s):  
Unsteady Flow ◽  
Steam Turbine ◽  
Measurement Data ◽  
Unsteady Aerodynamics ◽  
Low Pressure ◽  
Rotating Stall ◽  
Stage Model ◽  
Steam Turbines ◽  
Multi Stage ◽  
Low Volume

Non-synchronous excitation under low volume operation is a major risk to the mechanical integrity of last stage moving blades (LSMBs) in low-pressure (LP) steam turbines. These vibrations are often induced by a rotating aerodynamic instability similar to rotating stall in compressors. Currently extensive validation of new blade designs is required to clarify whether they are subjected to the risk of not admissible blade vibration. Such tests are usually performed at the end of a blade development project. If resonance occurs a costly redesign is required, which may also lead to a reduction of performance. It is therefore of great interest to be able to predict correctly the unsteady flow phenomena and their effects. Detailed unsteady pressure measurements have been performed in a single stage model steam turbine operated with air under ventilation conditions. 3D CFD has been applied to simulate the unsteady flow in the air model turbine. It has been shown that the simulation reproduces well the characteristics of the phenomena observed in the tests. This methodology has been transferred to more realistic steam turbine multi stage environment. The numerical results have been validated with measurement data from a multi stage model LP steam turbine operated with steam. Measurement and numerical simulation show agreement with respect to the global flow field, the number of stall cells and the intensity of the rotating excitation mechanism. Furthermore, the air model turbine and model steam turbine numerical and measurement results are compared. It is demonstrated that the air model turbine is a suitable vehicle to investigate the unsteady effects found in a steam turbine.

Design Factors Effecting Capacity of Rail and Transit Systems

2012 ◽  
Author(s):  
David F. Thurston
Keyword(s):  
Control Design ◽  
System Capacity ◽  
Optimized Design ◽  
Signal System ◽  
Key Factors ◽  
Transit Systems ◽  
Vehicle Type ◽  
Train Control ◽  
Rail Line ◽  
Design Factors

The overall impact on system “capacity” is typically described in terms of train control design. There are several other key factors that determine the ultimate system capacity of a rail line. Among the most influential of these are: vehicle type and configuration, stations and platform design and configuration, and overall civil alignment. In the analysis of the maximum capacity delivered from the train control system, all of these require optimization of design to achieve the highest throughput, and have a direct influenced by train control design as well. This paper describes how fully optimized design of non train control issues and factors have an impact on signal system design and have a consequence that is permanent once constructed.

Study on Optimal Circulation Dynamic System and Feasibility Analysis for a Solar Biogas Digester

2012 ◽  
Vol 164 ◽  
pp. 482-486
Author(s):  
You Zhang ◽  
Chang Sheng Peng ◽  
Feng Min Li
Keyword(s):  
Heat Transfer ◽  
Dynamic System ◽  
Heat Dissipation ◽  
Measurement Data ◽  
Hot Water ◽  
Feasibility Analysis ◽  
Operating Costs ◽  
Operating Efficiency ◽  
One Stage ◽  
Multi Stage

According to biogas digester heated by circulation of water heated by solar cell, three modes of hot water circulation dynamic system (one-stage cycle, multi-stage cycle, and continuous cycle) were proposed to reduce operating costs and optimize the operation. The results obtained showed that multi-stage cycle had a clear advantage in improving operating efficiency, the heat transfer of which was 41.57KJ, much higher than 7.21KJ of one-stage cycle and 2.20KJ of continuous cycle. A model was built to simulate the overall process of heat dissipation in comparison with what was obtained from the conventional experiments. Both the simulation and the experimental measurement data showed that multi-stage circulation dynamic system operated well.

Mach number and energy loss analysis inside multi-stage Tesla valves for hydrogen decompression

Energy ◽  
2019 ◽  
Vol 179 ◽  
pp. 647-654 ◽  
Author(s):  
Jin-yuan Qian ◽  
Min-rui Chen ◽  
Zhi-xin Gao ◽  
Zhi-jiang Jin
Keyword(s):  
Mach Number ◽  
Energy Loss ◽  
Loss Analysis ◽  
Multi Stage

scholarly journals Multi-Stage Transmission Network Planning Considering Transmission Congestion in the Power Market

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4910
Author(s):  
Yixin Huang ◽  
Xinyi Liu ◽  
Zhi Zhang ◽  
Li Yang ◽  
Zhenzhi Lin ◽  
...  
Keyword(s):  
Power System ◽  
Transmission Lines ◽  
Network Planning ◽  
Power Market ◽  
Mixed Integer ◽  
Transmission Network ◽  
Planning Model ◽  
Transmission Congestion ◽  
Multi Stage ◽  
Transmission Network Planning

The uncertainty of generation and load increases in the transmission network in the power market. Considering the transmission congestion risk caused by various uncertainties of the transmission network, the optimal operation strategies of the transmission network under various operational scenarios are decided, aiming for the maximum of social benefit for the evaluation of the degree of scenario congestion. Then, a screening method for major congestion scenario is proposed based on the shadow price theory. With the goal of maximizing the difference between the social benefits and the investment and maintenance costs of transmission lines under major congestion scenarios, a multi-stage transmission network planning model based on major congestion scenarios is proposed to determine the configuration of transmission lines in each planning stage. In this paper, the multi-stage transmission network planning is a mixed integer linear programming problem. The DC power flow model and the commercial optimization software CPLEX are applied to solve the problem to obtain the planning scheme. The improved six-node Garver power system and the simplified 25-node power system of Zhejiang Province, China are used to verify the effectiveness of the proposed multi-stage planning model.

scholarly journals A Highly Linear Low-Noise Transimpedance Amplifier for Indoor Fiber-Wireless Remote Antenna Units

Electronics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 437 ◽  
Author(s):  
Guillermo Royo ◽  
Antonio D. Martinez-Perez ◽  
Carlos Sanchez-Azqueta ◽  
Concepcion Aldea ◽  
Santiago Celma
Keyword(s):  
Cmos Technology ◽  
Antenna System ◽  
Open Loop ◽  
Low Noise ◽  
Total Power ◽  
Transimpedance Amplifier ◽  
Optimized Design ◽  
Error Vector Magnitude ◽  
Digitally Programmable ◽  
Total Power Consumption

This article presents an optimized design of a low-noise transimpedance amplifier (TIA) with high linearity for use in the downlink receiver of a remote antenna unit (RAU). The aim of this design is to be used in a cost-effective indoor distributed antenna system (DAS) for WLAN transmission using a mixed fiber-wireless system. The circuit topology consists of a fully differential shunt–shunt feedback TIA with digitally programmable transimpedance. An open-loop gain compensation technique is used to maintain stability and constant bandwidth (BW). The TIA has been fabricated in 65 nm CMOS technology with a 1.2 V voltage supply. The total power consumption of the TIA is 6 mW. A complete electrical and optical characterization with a 1550 nm PIN photodiode has been performed to demonstrate the reliable 54 Mb/s 802.11a WLAN transmission achieved with an error vector magnitude (EVM) lower than 3% for a 20 dB optical input range.

Thick Film Accelerometers in LTCC Technology—Design Optimization, Fabrication, and Characterization

2008 ◽  
Vol 5 (4) ◽  
pp. 150-155 ◽  
Author(s):  
Holger Neubert ◽  
Uwe Partsch ◽  
Daniel Fleischer ◽  
Mathias Gruchow ◽  
Alfred Kamusella ◽  
...  
Keyword(s):  
Design Optimization ◽  
Thick Film ◽  
Probability Distributions ◽  
Pressure Sensors ◽  
Measurement Data ◽  
Design Parameters ◽  
Optimized Design ◽  
System Failure ◽  
Functional Requirements ◽  
Leaf Springs

Diaphragms and beams for force and pressure sensors, e.g., are state of the art in mechanical elements of MEMS in LTCC technology. These elements sustain small strains and small deformations under load. A number of sensor and actuator applications, however, require movable elements that allow higher deformations while the local strains are still low. Springs, accelerometers, actuators, positioners, and valves are examples of such applications. For an accelerometer we developed an approach fabricate leaf springs, integrated into the LTCC technology. The working principle of the accelerometer is based on a seismic mass disposed on two parallel leaf springs that carry piezoresistors connected such that they form a measuring bridge. In the first design optimization step, we used an FEA model for finding an optimized design meeting our sensitivity requirements, inclusiding resonance frequency. In the second step, we made a tolerance analysis that calculates the probability distributions of functional variables from the probability distributions of the design parameters. This enables the probability of a system failure to be deduced. In a final design step, a design of the ceramic thick film accelerometer was calculated that minimizes the system failure probability. As a result we obtained a design optimized with respect to a set of functional requirements and design tolerances. The results of the computations using the FEA models were compared to results of measurement data acquired from prototypes of the accelerometer.

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