Seismic Reliability of UHV Porcelain arrester with Damping System

2014 ◽  
Vol 8 (1) ◽  
pp. 222-228 ◽  
Author(s):  
Xuesong Zhang ◽  
Meigen Cao ◽  
Zhicheng Lu
Keyword(s):  
Fragility Curves ◽  
Single Point ◽  
Analysis Method ◽  
Element Analysis ◽  
Seismic Reliability ◽  
Seismic Motion ◽  
Earthquake Model ◽  
New Type ◽  
The Mean ◽  
Very High

The vulnerability of the UHV porcelain arrester is very high under strong earthquake. To rise seismic reliability of the UHV porcelain arrester, a new type lead damper, which is a new patent product, is installed at the bottom of the equipment. To investigate the damping effect of the dampers, the experimental research and finite element analysis on seismic behavior of the UHV porcelain arrester with and without the dampers are carried out by means of single point input and single point output(SISO)measurement. The analyzed results show that the damper is well functioning, effectively decreasing stochastic earthquake response of the UHV porcelain arrester, thus the seismic reliability of porcelain arrester is improved. A seismic reliability analysis method is put forward based on the stochastic earthquake model .The mean and standard deviation of the seismic responses of the arrester with and without the dampers under the different site conditions are gained based on physical stochastic seismic motion model. Then its seismic reliability is calculated by the FOSM, and the fragility curves of the arrester are built. Calculation result shows that seismic reliability of the arrester with the dampers can be effectively enhanced under Ms 8.0 earthquake. A conclusion is given that the damper is capable to improve the seismic reliability of the UHV porcelain arrester effectively, and may be widely applied to the seismic design of the UHV porcelain arrester.

Evaluation of Football Helmets to Prevent Concussions

2014 ◽  
Author(s):  
David A. K. Kalapa
Keyword(s):  
Injury Risk ◽  
Brain Injuries ◽  
Football Players ◽  
Analysis Method ◽  
Element Analysis ◽  
Finite Element Analysis Method ◽  
Football Helmets ◽  
New Type ◽  
Contact Pressures ◽  
Reducing Potential

Football players experience impacts to the head, some of which cause mild traumatic brain injuries known as concussions. Players wear helmets to reduce injury risk, and this study compares two helmets to determine their effectiveness in reducing potential concussions. The helmets analyzed are a “classic” type made of large foam pad pieces, and a “new” type made of small honeycomb pads. Both helmets share the same external polycarbonate shell & padding materials. Three helmet to helmet collisions are studied: case one: “classic on classic,” case two: “classic on new,” & case three: “new on new.” Using finite element analysis method, stresses and contact pressures are calculated. For three collisions with the same forces applied, a player in case one experiences 0.96 MPa contact pressure at the skull, while a player in case three experiences 0.87 MPa. In case two the player wearing the “new” helmet is exposed to 0.9 MPa at the skull, while the player wearing the “classic” is exposed to 0.95 MPa at the skull. It is concluded that if a player uses a “classic” instead of “new” helmet, pressure on the skull is reduced by 9.4%, reducing the risk of that player sustaining a concussion.

Research on Analysis Method of Fatigue Strength for New Type Crushing Ripper Based on the Composite Load Spectrum

2014 ◽  
Vol 487 ◽  
pp. 378-384
Author(s):  
Feng Yi Lu ◽  
Xin Xin Liu ◽  
Ge Ning Xu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Strength ◽  
Strength Analysis ◽  
Analysis Method ◽  
Load Spectrum ◽  
Element Analysis ◽  
Structural Fatigue ◽  
The Finite Element Analysis ◽  
New Type

In view of the problem that new type crushing ripper installation of tamping equipment in circulation under the action of different load working multiple cases may occur structural fatigue damage, analysis of its force characteristic, establishment ripper rack compression bending component model, according to the working condition of the most unfavorable load combinations, using the allowable stress method to calculate structural fatigue strength; the combined effect of road load spectrum and vibrating load is also taken into consideration, then statics analysis and fatigue analysis of new type crushing ripper are calculated with the finite element analysis software Ansys Workbench. The results show that theoretical calculations are in accordance with the finite element analysis results, it evidences that the fatigue strength analysis method of crushing ripper is feasible and correct. It provides a reference for the anti-fatigue optimization design of new type crushing ripper, to guarantee its meet the operational requirements under of bad conditions.

The Study on Seismic Reliability of CS Panel Structure

2011 ◽  
Vol 368-373 ◽  
pp. 154-158
Author(s):  
Yan Bo Li ◽  
Chuan Fu Xu ◽  
Xue Yan Wang
Keyword(s):  
Finite Element ◽  
Seismic Response ◽  
Seismic Intensity ◽  
Experimental Models ◽  
Element Analysis ◽  
Seismic Reliability ◽  
Dynamic Reliability ◽  
Failure Theory ◽  
New Type ◽  
Set Up

CS Panel Residential Structure is a new type of structural system investigated and manufactured for the requirements of wall reformation and residential industrialization.Now set up two finite element models on the basis of the two types of three storeys CS panel structure experimental models (including tectonic columns or not ) with the ratio 1:2.8 that designed before. Then analyze the random seismic response of the two types of CS panel structure under the action of ground motion acceleration power spectrum using the spectrum analysis module of the finite element analysis software ANSYS.Based on the first excursion failure theory and stochastic vibration theory, dynamic reliability of the CS panel structure subject to different seismic intensity is calculated and compared, the effect of the edge component is summarized using structure seismic response of random statistic.

Design and Analysis of Hydrostatic Bearing Slide Used Linear Motor Direct-Drive

2011 ◽  
Vol 211-212 ◽  
pp. 666-670
Author(s):  
Guo An Hou ◽  
Tao Sun
Keyword(s):  
Dynamic Performance ◽  
Vertical Direction ◽  
Linear Motor ◽  
Analysis Method ◽  
Direct Drive ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Linear Encoder ◽  
Linear Slide ◽  
Very High

This paper discusses the design and analysis of a direct-drive linear slide used linear mortor. The alloy steel carriage is fully floated by twelve hydrostatic bearings, and it is force-closed. It has very high stiffnesses, 1700N/mm in vertical direction and 690N/mm in horizontal direction. The working stroke of slide is 200 mm. The slide is driven by a ironless linear motor. The optic linear encoder was used for the measurements and feedback. To analyze the static and dynamic performance of the slide, the modelling and simulation process, using the finite element analysis method, is presented.

The Clinical Outcomes of 234 Spiral Family Implants

2009 ◽  
Vol 10 (5) ◽  
pp. 50-57 ◽  
Author(s):  
Matteo Danza ◽  
Ophir Fromovich ◽  
Riccardo Guidi ◽  
Francesco Carinci
Keyword(s):  
Clinical Outcomes ◽  
Cox Regression ◽  
Primary Stability ◽  
Immediate Loading ◽  
Related Factors ◽  
Long Period ◽  
Kaplan Meier ◽  
New Type ◽  
The Mean ◽  
Very High

Abstract Aim Spiral family implants (SFIs) are a new type of implant fixture with a conical internal helix and a variable thread design. The aim of this retrospective study was to evaluate the clinical outcomes of a series of SFIs. Methods and Materials A total of 234 SFIs were placed in 86 patients (55 females and 31 males, median age 53 years) during the period between May 2004 and November 2007. The mean followup was 13 months. Several host, surgery, and implant-related factors were investigated, and the Kaplan Meier algorithm and the Cox regression were used to detect variables associated with the clinical outcome. Results Only nine out of 234 implants were lost (i.e., survival rate (SVR) of 96.2%) and no differences were detected among the studied variables. Conclusion SFIs have a high SVR similar to those reported in previous studies on different implant types. Clinical Significance SFIs demonstrated a very high primary stability which offers the potential for use of a specific implant device for immediate loading. However, additional studies are necessary to verify their outcome on the medium/long period. Citation Danza M, Formovich O, Guidi R, Carinci F. The Clinical Outcomes of 234 Spiral Family Implants. J Contemp Dent Pract [Internet]. 2009 Sept; 10(5). Available from: http://www.thejcdp.com/ journal/view/the-clinical-outcomes-of-234-spiralfamilyimplants_1.

Electrically Assisted Global Springback Elimination in AMS-T-9046 Titanium After Single Point Incremental Forming

2016 ◽  
Author(s):  
Tyler J. Grimm ◽  
John T. Roth ◽  
Ihab Ragai
Keyword(s):  
Sheet Metal ◽  
Manufacturing Industry ◽  
Incremental Forming ◽  
Single Point ◽  
Electrical Current ◽  
Stress Concentrations ◽  
Wall Angle ◽  
Element Analysis ◽  
New Type ◽  
Springback Reduction

Incremental Forming (IF) is a new type of sheet metal forming method being investigated by many because of its great potential in the manufacturing industry. The IF method forms sheet metal by use of a hemispherically shaped tool which follows a specified path that gradually forms the material as it traverses across the material. No dies are needed for this process, which is where the potential lies. IF is currently being researched in order to reduce the drawbacks of the process. These drawbacks include a maximum formable wall angle, degraded surface finish, low part accuracy, and local and global springback. This research focuses on the reduction of global springback, which arises from the stresses induced in the workpiece. This research approaches the problem with the use of electrical paths ran through the residual stress concentrations. The stress concentrations were mapped using Finite Element Analysis (FEA) and multiple tests were done to see which path had the greatest effect on springback. It was concluded that the best paths to apply electrical current through in order to reduce springback in an incrementally formed truncated pyramid are: along the formed corners from top to bottom, across the upper section of the formed corner, and along each side of the inner formed square. In addition, it was found that the path the electricity takes has a greater effect on the amount of springback reduction than the amount of paths applied. It is hypothesized that this is due to the stiffening effects of certain stresses.

On the Generation of Seaquake Velocity Fields for Submerged Floating Tunnel Structures

2013 ◽  
Vol 690-693 ◽  
pp. 1172-1175 ◽  
Author(s):  
Chun Xia Shi ◽  
Luca Martinelli
Keyword(s):  
Structural Engineering ◽  
Velocity Fields ◽  
Point Of View ◽  
Element Analysis ◽  
3D Finite Element ◽  
Practical Point ◽  
Seismic Motion ◽  
Hydrodynamic Loading ◽  
Submerged Floating Tunnel ◽  
New Type

Submerged Floating Tunnels are a new type of infrastructure, still representing a challenge in structural engineering both from the theoretical and the practical point of view. In this paper some issues arisen in generating the seaquake input (transmission through water of the effects of the seabed seismic motion) for a 3D finite element analysis of Submerged Floating Tunnels are presented and discussed. This loading source has been pointed out buy preliminary analyses as an important additional hydrodynamic loading on the tunnel which can play a significant role, and thus deserves further investigations.

scholarly journals Predicting stroke risk in Chinese hypertensive population using machine learning

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
X Huang ◽  
T Y Cao ◽  
Y P Wei ◽  
B Xu ◽  
H Y Wu ◽  
...  
Keyword(s):  
Machine Learning ◽  
Logistic Regression ◽  
General Framework ◽  
Primary Outcome ◽  
Stroke Risk ◽  
Prediction Method ◽  
Analysis Method ◽  
Hypertensive Population ◽  
The Mean ◽  
Very High

Abstract Background Stroke is the leading cause of death in China, and the stroke burden is especially high in rural areas. Risk prediction is essential for primary prevention of stroke. However, uncertainty remains about the optimal methodology for analyzing stroke risk. In this study, we aim to determine the most effective stroke prediction method in a targeted population and establish a general framework and pipeline for future analysis. Purpose 1) to determine the most effective stroke prediction method in a targeted population and 2) to establish a general framework and pipeline for future analysis. Methods Data were obtained from the China Stroke Primary Prevention Trial (CSPPT), a randomized, double-blind, multi-center clinical trial. 20,702 hypertensive patients without prior history of stroke were included in the study. The primary outcome was new nonfatal and fatal stroke (ischemic or hemorrhagic) occurring between baseline and follow-up (a median of 4.2 years). All suspected stroke cases were collected and further validated by the event adjudication committee. We compared two regression models (logistic regression and step wise logistic regression) and two machine learning methods (extreme gradient boosting and random forest). All models were trained using questionnaire data with and without laboratory data, then analyzed and compared. The primary outcome was defined as first stroke. Accuracy, sensitivity, specificity and AUCs (area under receiver operating characteristic curve) were used to assess each model. AUCs were used to evaluate the performance of each analysis method. Results In our data set with 20,702 samples and 127 variables, the highest AUCs (0.775 (0.725–0.826)) were observed with RUS (random under sampling) applied to RF (random forest). Before applying data balancing techniques, all analysis methods showed very low sensitivity (around 0.01), very high accuracy (around 0.97), and very high specificity (around 1.00). The mean AUCs were 0.741 (0.678–0.803). After data balancing techniques were applied, we observed an increase in sensitivity and decreases in accuracy and specificity. Different data balancing techniques had different effects on analysis methods. No significant effect on AUCs was observed; the range of increase and decrease was around 0.01. Similar overall patterns were observed when training with laboratory test data added. The mean AUCs were 0.739 (0.679–0.799) and 0.734 (0.674–9.795) for all models using data with and without laboratory test respectively. The 10 most important variables as determined by the model were selected as stroke risk predictors for all analysis models. Conclusion The most effective stroke prediction method in this Chinese rural hypertensive population is RUS applied to RF. The optimal analysis method and variable selection depends on data-specific features. FUNDunding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Key R&D Projects, Jiangxi [20203BBGL73173] National Key Research and Development Program [2016YFE0205400]

Monoamine Oxidase and Other Mitochondrial Enzymes in Density Subpopulations of Human Platelets

1988 ◽  
Vol 59 (01) ◽  
pp. 029-033 ◽  
Author(s):  
K G Chamberlain ◽  
D G Penington
Keyword(s):  
Monoamine Oxidase ◽  
Protein Concentration ◽  
Close Correlation ◽  
Human Platelets ◽  
Mitochondrial Enzymes ◽  
Density Fractions ◽  
Percoll Gradients ◽  
Normal Human ◽  
The Mean ◽  
Very High

SummaryNormal human platelets have been separated according to density on continuous Percoll gradients and the platelet distribution divided into five fractions containing approximately equal numbers of platelets. The mean volumes and protein contents of the platelets in each fraction were found to correlate positively with density while the protein concentration did not differ significantly between the fractions. Four mitochondrial enzymes (monoamine oxidase, glutamate dehydrogenase, cytochrome oxidase and NADP-dependent isocitrate dehydrogenase) were assayed and their activities per unit volume were found to increase in a very similar monotonie fashion with platelet density. When MAO and GDH were assayed on the same set of density fractions the correlation between the two activities was very high (r = 0.94–1.00, p <0.001) and a similar close correlation was found between MAO and ICDH. The results support the hypothesis that high density platelets either have a higher concentration of mitochondria or have larger mitochondria than low density platelets.

Voronoi Analysis of a Soccer Game

2004 ◽  
Vol 9 (3) ◽  
pp. 233-240 ◽  
Author(s):  
S. Kim
Keyword(s):  
Collective Behavior ◽  
Quantitative Assessment ◽  
The Other ◽  
Analysis Method ◽  
Random System ◽  
Soccer Game ◽  
Voronoi Polygons ◽  
The Mean

This paper describes a Voronoi analysis method to analyze a soccer game. It is important for us to know the quantitative assessment of contribution done by a player or a team in the game as an individual or collective behavior. The mean numbers of vertices are reported to be 5–6, which is a little less than those of a perfect random system. Voronoi polygons areas can be used in evaluating the dominance of a team over the other. By introducing an excess Voronoi area, we can draw some fruitful results to appraise a player or a team rather quantitatively.

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