Optimization in gravimetric terrain corrections

1984 ◽  
Vol 21 (5) ◽  
pp. 505-515 ◽  
Author(s):  
J. A. R. Blais ◽  
R. Ferland
Keyword(s):  
Computer Software ◽  
Point Of View ◽  
Test Results ◽  
Computational Problem ◽  
Gravimetric Measurements ◽  
Terrain Corrections

Terrain corrections for gravimetric measurements require topographical data of appropriate accuracy and density. The situation is clearly dependent on the ruggedness of the topography and the accuracy specifications for the terrain corrections. From the optimization point of view, this computational problem has been investigated and computer software developed for the near, intermediate, and distant zones surrounding the gravity stations. Test results indicate that the general accuracy objective of 1.0–1.5 mGal (10–15 μm s−2) for the gravimetric terrain corrections is easily achievable in practice with appropriate topographical data. For geophysical applications, higher accuracies are certainly achievable with the method, even in rugged areas.

The Properties of Welded Joints Made by 6082-T6 Aluminium Alloy and their Behaviour under Cyclic Loading Conditions

2015 ◽  
Vol 812 ◽  
pp. 375-380 ◽  
Author(s):  
D. Pósalaky ◽  
János Lukács
Keyword(s):  
Cyclic Loading ◽  
Automotive Industry ◽  
Welded Joints ◽  
Structural Engineering ◽  
Physical Simulation ◽  
Base Material ◽  
Point Of View ◽  
Test Results ◽  
Structural Elements ◽  
Effective Use

The magnitude of different aluminium alloys, especially the ones with higher strength, are increasing in the structural engineering, not just the usual applications (like the aerospace industry) but more likely in the automotive industry. There are more assumptions of the effective use of aluminium; we should highlight two important factors, the technological and the applicability criterions. The technological criterion is the joining of structural elements, frequently with welding thus the technological criterion ultimately is the weldability. The assumption of applicability comes from the loading capability of these structures, which is typically cyclic loading so the key issue from the point of view of applicability is the resistance to fatigue. This article represents physical simulation and fatigue test results both on the base material and on the welded joints.

Behaviors of Xiashu Loess in the Lower Reaches of China’s Yangtze River under Triaxial Compression and the Microscopic Explanations

2016 ◽  
Vol 858 ◽  
pp. 91-97
Author(s):  
Jun Hua Xiao ◽  
Wen Qi Zheng
Keyword(s):  
Mechanical Properties ◽  
Yangtze River ◽  
Shear Failure ◽  
Triaxial Compression ◽  
Processing Technique ◽  
Point Of View ◽  
Image Processing Technique ◽  
Test Results ◽  
Compression Tests ◽  
Triaxial Compression Tests

To investigate the macroscopic mechanical properties of undisturbed structural Xiashu loess in the lower reaches of China’s Yangtze River under triaxial compression, and obtain the intrinsic explanations for the macroscopic mechanical properties from the microscopic point of view, in laboratory, triaxial compression tests were carried out, microstructure images of sheared samples were collected by scanning electron microscope (SEM), and quantitative parameters of microstructure (mainly about particle or pore size, distribution, and alignment) were extracted by digital image processing technique. Based on the test results, the deviator stress-strain relationships of both undisturbed and remoulded Xiashu loess, the structural strength, and the microstructural evolution mechanism about the formation of shear failure zone of Xiashu loess under triaxial compression were analyzed.

scholarly journals Current State and Future Trends: A Citation Network Analysis of the Orthokeratology Field

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
Miguel Angel Sanchez-Tena ◽  
Cristina Alvarez-Peregrina ◽  
Jose Sanchez-Valverde ◽  
Cesar Villa-Collar
Keyword(s):  
Network Analysis ◽  
Computer Software ◽  
Citation Network ◽  
Research Field ◽  
Point Of View ◽  
Qualitative And Quantitative ◽  
Current State ◽  
Citation Network Analysis ◽  
Objective Representation ◽  
Flow Of Information

Introduction. Citation network analysis is a powerful tool that allows for a visual and objective representation of the past, present, and potential future directions of a research field. The objective of this study is using citation analysis network to analyse the evolution of knowledge in the field of orthokeratology. Materials and Methods. The database used in this citation networks analysis study was Scopus. The descriptor used was “orthokeratology” limited to three fields: title, keywords, and/or abstract, analysing the five most cited authors. Only articles cited at least twenty times were used. The computer software used was UCINET with two types of analysis, qualitative and quantitative. Results. 27 nodes have been included according to the search and inclusion criteria. In qualitative analysis, based on illustrate results, the relationships among nodes and their positions and connections show how the study of Cho et al. in 2005 is clearly positioned as a central cutoff point in the network. Quantitative analysis reveals the normalized value of the sample and shows how the study of Cho et al. in 2005 presents the highest percentage of input connections. Conclusions. This study shows the state of the flow of information in the orthokeratology field by providing links in bibliographic citations from a qualitative and quantitative point of view.

Out-of-specification test results from the statistical point of view

2007 ◽  
Vol 44 (3) ◽  
pp. 718-729 ◽  
Author(s):  
Heidi Köppel ◽  
Berthold Schneider ◽  
Hermann Wätzig
Keyword(s):  
Point Of View ◽  
Test Results ◽  
Specification Test ◽  
Statistical Point

New Steps to Improve Rotordynamic Stability Predictions of Centrifugal Compressors

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Manoj K. Gupta ◽  
Thomas A. Soulas ◽  
Dara W. Childs
Keyword(s):  
Centrifugal Compressor ◽  
Flow Model ◽  
Aerodynamic Performance ◽  
Magnetic Bearing ◽  
Point Of View ◽  
Test Results ◽  
Performance Point ◽  
Pressure Test ◽  
Full Pressure ◽  
Rotor Model

Improved rotordynamic stability is desired by end users, and centrifugal compressor manufacturers are expected to meet, if not exceed, this expectation. Compressor manufacturers are required to design and build machines that are rotordynamically stable on the test stand and in the field. Confidence has been established in predicting the excitation forces from seals and bearings, but impeller aerodynamic excitation forces continue to be a challenge. While much attention is paid to impellers from an aerodynamic performance point of view, more efforts are needed from a rotordynamic standpoint. A high-pressure, reinjection centrifugal compressor is analyzed in order to predict rotordynamic stability using the best available resources for seals and bearings. Impeller shroud forces are predicted using the bulk-flow model developed by Gupta and Childs (Gupta, M., and Childs, D., Proc. of ASME Turbo Expo 2000, Power for Land, Sea, and Air). Each impeller stage is analyzed and an attempt is made to improve the estimation of impeller aerodynamic excitation forces. Logarithmic decrement (log dec) predictions for the full rotor model consisting of all the stages and seals are compared to the full-load full-pressure test measured values using a magnetic bearing exciter. A good correlation is obtained between the measured test results and analytical predictions.

Bolt Load Changes Due to Internal Pressure in Gasketed Flange Connections

2003 ◽  
Author(s):  
Satoshi Nagata ◽  
Mitsuhiro Matsumoto ◽  
Toshiyuki Sawa
Keyword(s):  
Internal Pressure ◽  
Thrust Force ◽  
High Reliability ◽  
Constant Load ◽  
Point Of View ◽  
Load Factor ◽  
Test Results ◽  
Performance Point ◽  
Load Factors ◽  
Sealing Performance

Bolt load changes due to internal pressure are very important in order to evaluate the integrity of gasketed flange connections in the sealing performance point of view, because its gasket stress which dominates leak rate changes according to the bolt load changes. For establishing a connection possesses high reliability and sufficient integrity, it is necessary to clarify the mechanics ofgasketed flange connections. For this purpose, authors carried out experimental pressurizing tests for 3B and 20B gasketed flange connections clamped by various bolt preloads and measured the bolt load changes with increasing internal pressure up to 5MPa. Also a load factor, which is defined as the ratio of axial bolt force increment to pressure thrust force, was calculated using the test results. The test results indicate that 3B and 20B flange connections with the spiral wound gaskets have a constant load factors under sufficient initial clamping forces in assemble.

Gravimetric terrain corrections in western Canada

1983 ◽  
Vol 20 (2) ◽  
pp. 259-265 ◽  
Author(s):  
J. A. R. Blais ◽  
G. D. Lodwick ◽  
R. Ferland
Keyword(s):  
Western Canada ◽  
Gravimetric Measurements ◽  
Optimal Technique ◽  
Rugged Topography ◽  
Terrain Corrections ◽  
Theoretical Results

Terrain corrections for gravimetric measurements have been studied in terms of accuracy requirements and automated computations. Geodetic and geophysical applications in western Canada have been considered specifically because of complications arising from the rugged topography. Comparing the computation methods of Nagy and Mathisen in relation to the theoretical results, the former is shown to be more reliable with simulated accidented topography. Other approaches are also briefly discussed and general recommendations are made for an optimal technique to compute gravimetric terrain corrections in western Canada.

Adhesion Loss in Antistripping Agent Treated Asphalt Binders due to Moisture

2013 ◽  
Vol 690-693 ◽  
pp. 1553-1567 ◽  
Author(s):  
Md Arifuzzaman ◽  
Rafiqul A. Tarefder
Keyword(s):  
Statistical Tests ◽  
Asphalt Binder ◽  
Point Of View ◽  
Asphalt Binders ◽  
Test Results ◽  
Statistical Point ◽  
P Values ◽  
Modified Asphalt ◽  
Different Types

This study evaluates the role of antistripping agents to resist moisture-induced damage in asphalt binders. A total of five different types of antistripping agents are used. Plastomer and elastomer modified asphalt binders are used to modify the original base binder. Functionalized and non-functionalized AFM tips are used to determine adhesion in asphalt. With-CH3 tip, lime is found to be the most effective to protect moisture damage in asphalt binder as the adhesion loss is almost zero. The statistical tests show the Pearson values are very close to-1 that indicates a good correlation among the variables. Also the p-values are well below the prescribed value of 0.2% that indicates the test results to be significant from the statistical point of view.

scholarly journals Value of positive blood culture for Staphylococcus pettenkoferi - how not to make a mistake while interpreting the microbiological test results

2021 ◽  
Author(s):  
Kinga Markowska ◽  
Anna Majewska
Keyword(s):  
Bloodstream Infection ◽  
Biochemical Properties ◽  
Point Of View ◽  
Coagulase Negative Staphylococcus ◽  
Test Results ◽  
Microbiological Test ◽  
Clinical Point ◽  
Infection Diagnostics ◽  
Human Infections

Staphylococcus pettenkoferi is a coagulase negative staphylococcus (CoNS) whose clinical relevance is not fully understood. Hitherto, there are several reports describing the participation of this species in human infections; in most cases S. pettenkoferi was isolated from blood cultures. The purpose of this work is to summarize knowledge about S. pettenkoferi especially in terms of biochemical properties, types of infections caused, factors predisposing to bacteremia and susceptibility to antibiotics. Particular attention was paid to the difficulties in identifying this CoNS bacterium and limitations of microbiological tests. The principles of microbiological bloodstream infection diagnostics and criteria for interpreting test results are summarized, as well. The analysis of published reports and opinions resulted in better characterization of infections in which S. pettenkoferi is the etiological agent. From a clinical point of view, presented knowledge allows to assess the risk of bloodstream infection or sample contamination, help physician to implement the appropriate procedures and making decisions concerning inter alia empirical treatment.

scholarly journals CAE Modeling Rubber-metal Body Mounting of the Body-on-frame Car in Crash Simulations

2020 ◽  
Vol 14 ◽  
Keyword(s):  
Impact Test ◽  
Point Of View ◽  
The Body ◽  
Crash Test ◽  
Test Results ◽  
Rigid Connection ◽  
Metal Body ◽  
Stiffness Characteristics ◽  
The Impact ◽  
Crash Tests

The aim of the study was to research the behavior of the rubber-metal body mounting under various modeling options and to select the optimal, from the point of view of ensuring the accuracy of the results in the crash tests simulations. Body supports provide a link between the body and the car frame, and this has a critical effect on the impact test results of the car. The article discusses various options for modeling the body mounting by the degree of simplification from the simplest model with a rigid connection between the body and the frame to the model that takes into account the non-linearity of the stiffness characteristics of the supports, contact interaction between parts of the mounting and its surrounding parts, tension of the supports and failure. The results of virtual tests of a car with various options for modeling mountings were compared with the results of real tests. As a result of the study, a methodology for modeling the body supports was developed, which allows providing the necessary measurement error in virtual crash test modeling.

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