scholarly journals A Study on the Effects of Cross-sectional Dimension Change of Brake Pad Specimen on the Uncertainty of the Compressive Strength

2014 ◽  
Vol 17 (4) ◽  
pp. 223-227
Author(s):  
Soo Hong Park ◽  
Jin Kyu Park ◽  
Si Wan Kim ◽  
Chan Kyoung Park
Keyword(s):  
Compressive Strength ◽  
Brake Pad ◽  
Cross Sectional ◽  
Cross Sectional Dimension ◽  
Dimension Change

scholarly journals Modeling Uniaxial Bond Stress–Slip Behavior of Reinforcing Bars Embedded in Concrete with Different Strengths

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 783
Author(s):  
Chao-Wei Tang
Keyword(s):  
Compressive Strength ◽  
Bond Stress ◽  
Constitutive Relationship ◽  
Central Position ◽  
Test Results ◽  
Reinforcing Bars ◽  
Cross Sectional ◽  
Reinforcing Bar ◽  
Cross Sectional Dimension ◽  
Center Section

This paper aims to study the uniaxial bond stress–slip characteristics of reinforcing bars embedded in concrete with different strengths. Tests were conducted on tension–pull specimens that had a cross-sectional dimension with a reinforcing bar embedded in the center section. The experimental variable was the concrete compressive strength (20, 40, and 60 MPa). The test results show that in the specimen subjected to any fixed load, the maximum value of the concrete strain occurred around the central position, and its value increased as the compressive strength of the concrete increased. Depending on the embedded position of the steel bars, the bond stress–slip relationship was also different. In addition, the analytical results indicate that the proposed bond stress–slip constitutive relationship is very accurate in describing the true bond stress–slip relationship.

Review of Fire Performance Experiment of Concrete-Filled Steel Tubular Columns

2014 ◽  
Vol 638-640 ◽  
pp. 1397-1401
Author(s):  
Kai Xiang ◽  
Guo Hui Wang ◽  
Yan Chong Pan
Keyword(s):  
Load Ratio ◽  
Experimental Results ◽  
Research Progress ◽  
Future Research ◽  
Fire Performance ◽  
Cross Sectional ◽  
Tubular Columns ◽  
Cross Sectional Dimension ◽  
Cfst Columns ◽  
In Fire

This paper presents a review of research progress in fire performance of concrete-filled steel tubular (CFST) columns. Experimental results of CFST columns in fire are reviewed with influence parameters, such as heights, cross-sectional dimension, section types, concrete types, concrete strengths, load ratio, load eccentricity, fire exposed sides and so on. Some conclusions of CFST columns under fire conditions are summarized. Deficiencies in the fire performance experiments of CFST columns are identified, which provide the focus for future research in the field.

Fabrication and Mechanical Properties of Dense/Porous β-Tricalcium Phosphate Bioceramics

2007 ◽  
Vol 330-332 ◽  
pp. 907-910
Author(s):  
Fa Ming Zhang ◽  
Jiang Chang ◽  
Jian Xi Lu ◽  
Kai Li Lin
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Exponential Growth ◽  
Weight Bearing ◽  
Area Ratio ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Matrix ◽  
Porous Bioceramics

Attempt to increase the mechanical properties of porous bioceramics, a dense/porous structured β-TCP bioceramics that mimic the characteristics of nature bone were fabricated. Experimental results show that the dense/porous structured β-TCP bioceramics demonstrated excellent mechanical properties with compressive strength up to 74 MPa and elastic modulus up to 960 MPa, which could be tailored by the dense/porous cross-sectional area ratio obeying the rule of exponential growth. The interface between the dense and porous bioceramics is connected compactly and tightly with some micropores distributed in the matrix of both porous and dense counterparts. The dense/porous structure of β-TCP bioceramics may provide an effective way to increase the mechanical properties of porous bioceramics for bone regeneration at weight bearing sites.

Behaviour of cold-formed steel built-up I-section columns composed of four U-profiles

2018 ◽  
Vol 22 (3) ◽  
pp. 613-625 ◽  
Author(s):  
M Anbarasu ◽  
M Venkatesan
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Ultimate Strength ◽  
Element Model ◽  
Cross Sectional ◽  
Direct Strength Method ◽  
The North ◽  
Compression Members ◽  
Cross Sectional Dimension ◽  
Cold Formed Steel

This work reports numerical results concerning the cold-formed steel built-up I-section columns composed of four U-profiles under axial compression. A finite element model is developed by using the software program ABAQUS. The developed model includes geometric, material nonlinearities and geometric imperfections. The finite element model was verified against the experimental results reported in the cold-formed steel built-up open section columns. In the parametric study, the sections are analysed with several cross-sectional dimension ratios and lengths, in order to assess their influence on the buckling behaviour and ultimate strength of cold-formed steel built-up I-section columns. After presenting and discussing the numerical parametric results, the article shows that the current direct strength method in the North American Specification for cold-formed steel compression members design curve fails to predict adequately the ultimate strength of some of the columns analysed and addresses the modification proposed on current direct strength method curves, providing improved predictions of all the numerical ultimate strength available. The proposed method is also assessed by reliability analysis.

Testing for individual sphericity in heterogeneous panels

Biometrika ◽  
2019 ◽  
Vol 106 (3) ◽  
pp. 740-747
Author(s):  
Simon A Broda
Keyword(s):  
Distribution Function ◽  
Normal Approximation ◽  
Empirical Work ◽  
Null Distribution ◽  
Saddlepoint Approximation ◽  
Test Statistic ◽  
Cross Sectional ◽  
P Values ◽  
Cross Sectional Dimension ◽  
Heterogeneous Panels

Summary This manuscript considers locally best invariant tests for sphericity in heterogeneous panels. A new integral representation for the characteristic function of the test statistic under the null is presented, along with an algorithm for inverting it to obtain the distribution function. A saddlepoint approximation to the null distribution addresses the need to quickly compute approximate $p$-values in empirical work. The approximation shows substantial improvements over the normal approximation when the cross-sectional dimension is small.

scholarly journals Bias correction methods for dynamic panel data models with fixed effects

2017 ◽  
Vol 6 (2) ◽  
pp. 58
Author(s):  
Mohamed Abonazel
Keyword(s):  
Panel Data ◽  
Fixed Effects ◽  
Generalized Method Of Moments ◽  
Dynamic Panel Data ◽  
Estimation Methods ◽  
Time Dimension ◽  
Dynamic Panel ◽  
Cross Sectional ◽  
Cross Sectional Dimension ◽  
Ls Estimator

This paper considers the estimation methods for dynamic panel data (DPD) models with fixed effects, which suggested in econometric literature, such as least squares (LS) and generalized method of moments (GMM). These methods obtain biased estimators for DPD models. The LS estimator is inconsistent when the time dimension (T) is short regardless of the cross-sectional dimension (N). Although consistent estimates can be obtained by GMM procedures, the inconsistent LS estimator has a relatively low variance and hence can lead to an estimator with lower root mean square error after the bias is removed. Therefore, we discuss in this paper the different methods to correct the bias of LS and GMM estimations. The analytical expressions for the asymptotic biases of the LS and GMM estimators have been presented for large N and finite T. Finally; we display new estimators that presented by Youssef and Abonazel [40] as more efficient estimators than the conventional estimators.

scholarly journals HOW IMPORTANT IS INNOVATION? A BAYESIAN FACTOR-AUGMENTED PRODUCTIVITY MODEL BASED ON PANEL DATA

2016 ◽  
Vol 20 (8) ◽  
pp. 1987-2009 ◽  
Author(s):  
Georges Bresson ◽  
Jean-Michel Etienne ◽  
Pierre Mohnen
Keyword(s):  
Common Factors ◽  
Gdp Per Capita ◽  
Factor Productivity ◽  
Technology Infrastructure ◽  
Cross Sectional ◽  
Cross Sectional Dimension ◽  
Specific Factors ◽  
Per Capita ◽  
Bayesian Factor ◽  
Time Specific

This paper proposes a Bayesian approach to estimating a factor-augmented GDP per capita equation. We exploit the panel dimension of our data and distinguish between individual-specific and time-specific factors. On the basis of 21 technology, infrastructure, and institutional indicators from 82 countries over a 19-year period (1990 to 2008), we construct summary indicators of each of these three components in the cross-sectional dimension and an overall indicator of all 21 indicators in the time-series dimension and estimate their effects on growth and international differences in GDP per capita. For most countries, more than 50% of GDP per capita is explained by the four common factors we have introduced. Infrastructure is the greatest contributor to total factor productivity, followed by technology and institutions.

scholarly journals Effect of Side Surface Orientation on the Mechanical Properties of Silicon Nanowires: A Molecular Dynamics Study

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 102 ◽  
Author(s):  
Xiao Zhuo ◽  
Hyeon Beom
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Silicon Nanowires ◽  
Side Surface ◽  
Surface Orientation ◽  
Dislocation Nucleation ◽  
Cross Sectional ◽  
Tension And Compression

We investigated the mechanical properties of <100>-oriented square cross-sectional silicon nanowires under tension and compression, with a focus on the effect of side surface orientation. Two types of silicon nanowires (i.e., nanowires with four {100} side surfaces and those with four {110} side surfaces) were simulated by molecular dynamics simulations at a temperature of 300 K. The deformation mechanism exhibited no dependence on the side surface orientation, while the tensile strength and compressive strength did. Brittle cleavage was observed under tension, whereas dislocation nucleation was witnessed under compression. Silicon nanowires with {100} side surfaces had a lower tensile strength but higher compressive strength. The effect of side surface orientation became stronger as the nanowire width decreased. The obtained results may provide some insight into the design of silicon-based nano-devices.

scholarly journals Cross-Sectional Dimension Dependence of Electroosmotic Flow in Fractal Treelike Rectangular Microchannel Network

Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 266 ◽  
Author(s):  
Dalei Jing ◽  
Xuekuan Zhan
Keyword(s):  
Surface Area ◽  
Electroosmotic Flow ◽  
Scaling Laws ◽  
Channel Length ◽  
Channel Height ◽  
Rectangular Microchannel ◽  
Cross Sectional ◽  
Cross Sectional Dimension ◽  
Fluidic Resistance ◽  
Fractal Network

The present work theoretically and numerically studies the electroosmotic flow (EOF) within a fractal treelike rectangular microchannel network with uniform channel height. To obtain minimum EOF fluidic resistance, the microchannel cross-sectional dimensions of the fractal network are optimized. It is found that the cross-sectional dimension dependence of EOF fluidic resistance within a symmetric fractal network is only dependent on the channel width when the total channel volume is constant, and the optimal microchannel widths to reach the minimum EOF fluidic resistance satisfy the scaling law of κ = N−1 (where κ is the width ratio of the rectangular channels at two successive branching levels, N is the branching number); however, for the symmetric fractal network with constant total surface area, the optimal cross-sectional dimensions should simultaneously satisfy κ = N−1 and H = S 4 l 0 1 − γ N 1 − ( γ N ) m + 1 (where H is the channel height, S is the total channel surface area, l0 is the channel length at the original branching level, γ is the channel length ratio at two successive branching levels and m is the total branching level) to obtain the minimum EOF fluidic resistance. The optimal scaling laws established in present work can be used for the optimization design of the fractal rectangular microchannel network for EOF to reach maximum transport efficiency.

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