Simulation Research on Optical Performance of Multicrystalline Silicon Texture Structure

2014 ◽  
Vol 599-601 ◽  
pp. 99-102
Author(s):  
Fa Yun Zhang
Keyword(s):  
Power Flow ◽  
Light Trapping ◽  
Element Model ◽  
Multicrystalline Silicon ◽  
Optical Performance ◽  
Simulation Research ◽  
Surface Magnetic Field ◽  
Before And After ◽  
Hole Model ◽  
Extremum Value

The finite element model of double etching pits was established, optical performance of multicrystalline silicon wafer before and after etching was simulated by RF MODULE of COMSOL Multiphysics version 3.5a. Optical characteristic of unetching wafer and acidic textured were compared. It is indicates that acidic textured (double etching pits) has low reflectivity, high power flow Y component , the better light trapping. When the wavelength is 600nm, the maximum and minimum value of surface electric field Z component of acidic textured are 1.9 times and 1.4 times respectively than that of unetching wafer, and two extremum value of surface magnetic field Z component are 2.1 times and 1.9 times respectively than that of unetching wafer. Numerical simulation results of Multi hole model are closely with experimental values, which can guide the practical production.

scholarly journals Dynamic grid fault analysis in wind power plant with DFIG by using supervisory control and data acquisition (SCADA) viewer

2020 ◽  
Vol 181 ◽  
pp. 03006
Author(s):  
Nduwamungu Aphrodis ◽  
Ntagwirumugara Etienne ◽  
Utetiwabo Wellars ◽  
Mulolani Francis
Keyword(s):  
Power Systems ◽  
Power Flow ◽  
Control Strategies ◽  
Electrical Power ◽  
Fault Analysis ◽  
Operational Mode ◽  
Electrical Power Systems ◽  
Fault Ride Through ◽  
Before And After ◽  
Clearing Time

Faults in electrical power systems are among the key factors and sources to network disturbances, however control strategies are among key faults clearing techniques for the sake of safe operational mode of the system.Some researchers have shown various limitations of control strategies such as slow dynamic response,inability to switch Off and On network remotely and fault clearing time. For a system with wind energy technologies, if the power flow of a wind turbine is interrupted by a fault, the intermediate-circuit voltage between the machine-side converter and line-side converter will fall in unacceptably high values.To overcome the aforementioned issues, this paper used a Matlab simulations and experiments in order to analyze and validate the results.The results showed that fault ride through (FRT) with SCADA Viewer software are more adaptable to the variations of voltage and wind speed in order to avoid loss of synchronism. Therefore at the speed of 12.5m/s a wind produced a rated power of 750W and remained in synchronization before and after a fault created and cleared but worked as generator meanwhile at speed of 3.4m/s wind disconnected from grid and started working as a motor and consumed active power (P=-25watts) and voltage dip at 100% .For the protection purpose, the DC chopper and crowbar should be integrated towards management of excess energy during faults cases.

Experimentally Validated Computational Simulation of Lumbar Spine Intervertebral Disc Puncture

2011 ◽  
Author(s):  
Kristen E. Lipscomb ◽  
Nesrin Sarigul-Klijn
Keyword(s):  
Back Pain ◽  
Lumbar Spine ◽  
Intervertebral Disc ◽  
Nucleus Pulposus ◽  
Chronic Back Pain ◽  
Medical Condition ◽  
Computational Simulation ◽  
Element Model ◽  
Before And After ◽  
Spine Model

Back pain is a debilitating medical condition, often with an unclear source. Over time, back pain can affect the work and lifestyle of an individual by reducing job productivity and time spent on enjoyable activities. Discography of the intervertebral disc (IVD) is often used to diagnose pathology of the disc and determine if it may be a source for chronic back pain. It has recently been suggested that discography may lead to IVD degeneration, and has been a cause of controversy among spine care physicians. Using the results from a cadaveric experimental model, a finite element model was first validated. Then, a study was conducted to better understand the changes caused by discography on human spine mechanics. An anatomically accurate L3-L5 lumbar spine model was developed using computed tomography scans. Discography was simulated in the model as an area in the disc affected by needle puncture. The material properties in the nucleus pulposus were adjusted to match experimental data both before and after puncture. The results show that puncture of the IVD leads to increased deformation as well as increased stresses in the disc. Pressure in the nucleus pulposus found to decrease after puncture, and was calculated in the course of this study. Puncturing the IVD changes disc mechanics and may lead to progressive spine issues in the future such as disc degeneration. While discography has been the gold standard to determine if the disc was a source of back pain in patients for many years, the potential long-term degenerative effects of the procedure are only now coming into light, and must be closely examined.

Simulation Research on Cross-Sectional Stability of Expanded Diameter Conductors Based on ANSYS

2012 ◽  
Vol 256-259 ◽  
pp. 2838-2843
Author(s):  
Jia Jun Si ◽  
Jian Cheng Wan ◽  
Bin Liu ◽  
Yao Ding
Keyword(s):  
Power Transmission ◽  
Element Model ◽  
Aluminum Wire ◽  
Key Factors ◽  
Cross Sectional ◽  
Simulation Research ◽  
Contact Points ◽  
Electricity Power ◽  
The Wire ◽  
Significant Factors

The expanded diameter conductors are widely used for high voltage electricity power transmission due to its superior ability to prevent electronic corona phenomenon. However an undesired stability problem of wire distribution configuration within the cross-section of the conductor often occurs during the power line stringing processes, especially for the not-well-designed conductor structures. This phenomenon is typically characterized by the appearance of outer wire/wires jumping out of the layer; therefore it is also referred as wire jump-out problem. Finite element model which can predict the wire jump-out phenomenon has been successfully developed in this research project. Series of stimulations have been carried out to investigate the key factors to cause the wire jump-out problem. The reduction of radial distances between the adjacent aluminum wire layers due to the obvious indentation deformation at the trellis contact points were identified to be one of the most significant factors to lead to the wire jump-out problem. Numerical results show that keeping sufficient initial gap between the adjacent outer layer wires in the initial design can be a simple effective way to relieve/avoid the wire jump-out problem.

Efficient Component-Based Vibration and Power Flow Analysis of a Vehicle Structure

2001 ◽  
Author(s):  
Yung-Chang Tan ◽  
Soo-Yeol Lee ◽  
Matthew P. Castanier ◽  
Christophe Pierre
Keyword(s):  
Power Flow ◽  
Flow Analysis ◽  
Element Model ◽  
Reduced Order Model ◽  
Order Model ◽  
Component Structure ◽  
Modeling And Analysis ◽  
Reduced Order ◽  
Vehicle Structure ◽  
Entire Vehicle

Abstract A case study on the efficient prediction of vibration and power flow in a vehicle structure is presented. The modeling and analysis technique is based on component mode synthesis (CMS). First, the finite element model (FEM) of the entire vehicle structure is partitioned into component models. Then, the Craig-Bampton method is used to assemble a CMS model of the vehicle. The CMS matrices are further reduced by finding characteristic constraint (CC) modes. A relatively small number of CC modes are selected to capture the primary motion of the interface between components, yielding a highly reduced order model of the vehicle vibration in the low- to mid-frequency range. Using this reduced order model (ROM), the power flow and vibration response of the vehicle is analyzed for several design configurations. A design change in one component structure requires a re-analysis of the FEM for that component only, in order to generate a new ROM of the entire vehicle. It is found that this component-based approach allows efficient evaluation of the effectiveness of the vehicle design changes.

Performance of a Post-Byzantine Triple-Domed Basilica under Near and Far Fault Seismic Loads

2015 ◽  
pp. 831-867 ◽  
Author(s):  
Constantine C. Spyrakos ◽  
Charilaos A. Maniatakis ◽  
Panagiotis Kiriakopoulos ◽  
Alessio Francioso ◽  
Ioannis M. Taflampas
Keyword(s):  
Structural Damage ◽  
New Technology ◽  
Element Model ◽  
Seismic Loads ◽  
Regional Seismicity ◽  
Near Fault ◽  
Collapse Mechanisms ◽  
Before And After ◽  
Out Of Plane ◽  
Structural Parts

In this Chapter a triple-domed basilica constructed at the end of the 19th century is selected as a case study to present a methodology for the selection of the appropriate intervention techniques in monumental structures. The methodology includes in-situ and laboratory testing, application of analytical methods, consideration of geotechnical parameters and regional seismicity. Seismic loads are estimated according to contemporary and older concepts for seismic design. Since the impact of near-fault phenomena on masonry structures has not been thoroughly studied, although considered as responsible for extensive structural damage during major seismic events, a procedure is presented in order to account for the special characteristics of strong ground motion, in the so-called near-fault region. The seismic performance of the structure before and after interventions, using traditional and new technology, is assessed by applying a validated finite element model. Also, the out-of-plane behavior of structural parts is evaluated through kinematic analysis of selective collapse mechanisms.

Dynamic Characteristics Analysis and Structural Topology Optimization of the Plane Grinder

2016 ◽  
Vol 693 ◽  
pp. 471-478
Author(s):  
Rui Tao Peng ◽  
Wang Yan ◽  
Xin Zi Tang ◽  
Zhuan Zhou
Keyword(s):  
Machine Tool ◽  
Dynamic Characteristics ◽  
Weak Link ◽  
Element Model ◽  
Variable Density ◽  
Structural Topology ◽  
Static And Dynamic Characteristics ◽  
Before And After ◽  
Characteristics Analysis ◽  
Dynamic Characteristics Analysis

The dynamic characteristic is one of the important indicators which determine the performance of a machine tool, in this paper, the finite element model of a plane grinder is established with consideration of the behavior of joint, the static dynamic characteristics of machine tools are analyzed to reveal the vibration weak link, the column structure is topology optimized and redesigned based on the variable density degradation method. Static and dynamic characteristics of the original and new column are compared, and the dynamic characteristics of the machine tool before and after modification are discussed. The results indicate that the static and dynamic characteristics of the plane grinder are all improved after optimization.

Capacitive and Inductive Line Reactance for Network Reconfiguration

2017 ◽  
Vol 8 (3) ◽  
pp. 751
Author(s):  
Aiman Suhailah Saifuddin ◽  
Karmila Kamil ◽  
Halimatun Hashim ◽  
Ruthraganapathy Radhakrishnan
Keyword(s):  
Renewable Energy ◽  
Transmission Line ◽  
Solar Irradiance ◽  
Power Flow ◽  
Stability Index ◽  
Test System ◽  
Network Reconfiguration ◽  
Solar Pv ◽  
Before And After ◽  
Excess Power

<p>Solar PV may cause power congestion to occur in a transmission line when there is high solar irradiance that causing solar PV to generate more power flow than demanded power flow. Transmission line congestion that can be made worst by adding extra power generating farm such as centralized PV farm of renewable energy which helps to deliver customers with the demand or load required. The power generated coming from solar PV is depending on the weather and can definitely worsen the flow in transmission line due to the power captured. In this case, the high solar irradiance can affect the power generated from solar PV and will cause power congestion when power generated is higher than the load demanded. In this paper, the proposed method used to overcome the power congestion in a transmission line is by rerouting the excess power from the overloaded line to underloaded line by changing the line reactance of the line. An IEEE 30 bus test system is developed in PSS/E software as the test system. The output monitored is the line stability index of the affected line before and after rerouting process.</p>

A Discussion on the measurement and interpretation of changes of strain in the Earth - Methods for prediction and evaluation of tidal tilt data from borehole and observatory sites near active faults

1973 ◽  
Vol 274 (1239) ◽  
pp. 245-252 ◽  
Keyword(s):  
San Francisco ◽  
Active Faults ◽  
Earthquake Hazard ◽  
Element Model ◽  
Lower Shear ◽  
The Pacific ◽  
Before And After ◽  
Ocean Loading ◽  
Local Earthquake ◽  
Linear Slope

Tilt has been measured continuously at tidal sensitivity in borehole and observatory sites in the San Francisco Bay region, California. These sites, within a few kilometres of a m ajor fault and the Pacific Ocean, are part of an extensive network measuring strain and microseismicity. Static response of the Presidio site to ocean loading at the M 2 frequency best fits a finite-element model with lower shear modulus in the San Andreas fault zone than in adjacent material at the same depth. The Presidio tilt data exhibit a secular trend less than 3 (rrad/year superim posed on local earthquake and meteorological effects. On two occasions earthquakes (M„ > 4.3) occurred within 55 km of a station and were preceded by anom alous tilt accumulating to 1 ^rad over several days with an accelerated rate of tilt a few hours before the events. The root-mean-square (r.m.s.) difference for two stations of 25 km apart for 700 h before and after one of these events was 5 x 10-8 and 2 x 10 ^ respectively . A similar r.m.s. difference was observed before and after a larger ( M b> 5) but more distant (180 km) earthquake from the same two stations. This latter event did not, however, exhibit the extreme linear slope (10~9 rad/h) of the two earlier earthquakes. Although such anomalies can be correlated with meteorological activity over short periods of time, they do not correlate for periods approaching one month. A transfer function derived during a period w hen there were no local earthquakes can be used for calculating tilt response to surface loading from telemetered meteorological and tilt data. These results can then be input for a prediction beyond the data, and the error in prediction monitored as a final output for instrument performance and potential earthquake hazard.

Analysis on Effect of Tunnel Crossing Underneath Foundation of Tall Buildings on Anti-Seismic Mortar Anchor in Weathered Rock Area

2012 ◽  
Vol 446-449 ◽  
pp. 2581-2589
Author(s):  
Xiao Bei Shi ◽  
Kai Wei ◽  
Bing Long Wang ◽  
Da Wei Huang
Keyword(s):  
High Speed ◽  
Failure Process ◽  
Tall Buildings ◽  
Element Model ◽  
Tunnel Excavation ◽  
High Speed Railway ◽  
Weathered Rock ◽  
Whole Process ◽  
Influence Area ◽  
Before And After

Depending on a project of constructing a tunnel of high-speed railway which crosses underneath the foundation of tall buildings in weathered rock area, the paper analyzes the failure process and its law of anti-seismic mortar anchors under the foundation of tall buildings by simulating the whole process of construction with finite element model. Then the coverage scope, influence rules and extent of tunnel excavation on the anti-pulling effect and stability of mortar anchors are analyzed according to the changes of lateral pressure and axial force of anti-seismic mortar anchors before and after construction. The results show that the influence area can be divided into three parts， of which the main area where the anti-seismic mortar anchors are badly affected is on the top of the tunnel and extends horizontally to a certain range. Finally, the paper gives an applicable method to estimate the area where the anti-seismic mortar anchors should be strengthened by grouting, which also applies to the similar projects in weathered rock area.

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