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The Relationship of modulus of elasticity and Micro-Hardness of Denture Bases to Pressure Transmission under the Thermoplastic Nylon Denture Base

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JOURNAL OF BIOMIMETICS BIOMATERIALS AND BIOMEDICAL ENGINEERING 2020年第1期48卷 134-140页

作者： Andryas, Ika Nasution, Hubban Univ Sumatera Utara Fac Dent Dept Prosthodont Jalan Alumni 2 Medan 20155 Indonesia

Introduction: The purpose of this study was to evaluate the relationship of modulus of elasticity and micro-hardness of denture bases to pressure transmission under the thermoplastic nylon denture base. Material and Methods: Mandibular first molar acrylic denture teeth (Bioeco) embedded on 15x15x3 mm(3) thermoplastic nylon (TCS and BioTone) and poly methyl methacrylate denture bases were evaluated (n=9). A 100N force applied on the specimen using universal testing machine and the pressure transmitted under the specimen observed using pressure transducer. The modulus of the elasticity (n=16) measured on 64x10x3,3 mm(3) specimens and micro-hardness (n=16) measured on 10x10x3 mm(3) specimens. Data were statistically analyzed using One-way Anova followed by Tukey HSD post hoc test. Pearson correlation test used to evaluate the relationship of modulus of elasticity and micro-hardness on denture bases to pressure transmission (alpha >= 0,05). Results: The results showed that poly methyl methacrylate has the highest pressure transmission compared to others. There was a significant relationship between modulus of elasticity and micro hardness to pressure transmission under the denture base. Discussion: This study can help dentists to determine the design of dentures, especially in the selection of denture base materials.

关键词： Denture base micro-hardness pressure transmission modulus of elasticity thermoplastic nylon

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Effect of bending and compressive modulus of elasticity on the behaviour of timber-alternative railway sleepers supported by ballast

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CASE STUDIES IN CONSTRUCTION MATERIALS 2021年 15卷

作者： Salih, Choman Manalo, Allan Ferdous, Wahid Yu, Peng Abousnina, Rajab Heyer, Tom Schubel, Peter Univ Southern Queensland Ctr Future Mat CFM Toowoomba Qld 4350 Australia Austrak Pty Ltd Brisbane Qld 4000 Australia

Alternative railway sleeper technologies for replacement of timber are made of materials possessing a wide range of bending and compressive moduli. This poses a great challenge to railway authorities and engineers in designing a railway track supported by different sleeper technologies. This study evaluates the static behaviour of a railway track supported by different alternative railway sleeper technologies, i.e. recycled plastics (1.0 GPa), synthetic composites (7.4 GPa), timber (13.0 GPa), and low profile prestressed concrete sleepers (38.0 GPa), using a ballast box test representing a single sleeper section of a track. The deflection profiles along the length of the sleepers under a full service load was captured using Digital Image Correlation technique combined with the strain measurements at the top-centre of the sleepers. Three-dimensional Finite Element simulation of the sleepers' behaviour based on the Beam on Elastic Foundation theory was implemented and validated by the experimental results. The results show that sleepers with bending modulus of less than 13.0 GPa will have W-shape deflection profile and a high rail seat deflection while sleepers with a bending modulus of 38.0 GPa will show nearly flat behaviour. Local deformation at the rail seat region accounts for almost 6 % of the total deflection of sleepers on a low subgrade modulus and as high as 10 % for high subgrade modulus. The results of this study provide a better insight into the in-track behaviour of alternative sleeper technologies having distinctive material properties.

关键词： Composite sleeper Timber-alternative sleeper Ballast box test Beam on elastic foundation (BOEF) modulus of elasticity Compressive modulus

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AN OPTIMIZED STATISTICAL MODEL FOR PREDICTING COMPOSITE modulus of elasticity

AN OPTIMIZED STATISTICAL MODEL FOR PREDICTING COMPOSITE MODU...

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ASME International Mechanical Engineering Congress and Exposition (IMECE)

作者： Hage, Ilige S. Hage, Re-Mi Ghnatios, Chady Baydoun, Ahmad M. R. Hamade, Ramsey F. Notre Dame Univ Louaize Dept Mech Engn POB 72 Zouk Mosbeh Lebanon Notre Dame Univ Louaize Dept Math & Stat POB 72 Zouk Mosbeh Lebanon Notre Dame Univ Louaize Mech Engn POB 72 Zouk Mosbeh Lebanon Amer Univ Beirut Dept Mech Engn POB 11-0236 Beirut 11072020 Lebanon

ISBN: (纸本)9780791884492

Composites are the revolutionary materials that were developed for the ease of the technology. Similar to all families of materials, composites are being extensively studied nowadays. One of the composites' main studies is the homogenization study to determine composites modulus of elasticity function of multiple variables based on differentiating several inclusions' geometries, or quantities or orientations. However, homogenization studies require extensive numerical and analytical work. This work uses a statistical optimized tool TS-REG (tabu search combined with statistical regression proven to achieve models with the highest R-squared and lowest p-values for each variable in addition to the lowest MAPE (mean absolute percentage error)) to predict a model relating composite modulus of elasticity to inclusions shape (as aspect ratio), volume fraction, and orientation (0-30-60-90 degrees). Experimental data of modulus of elasticity compressed 3D printed ABS plastics cubes of 16x16x16 mm3 size having one inclusion (as empty spheres or ellipsoids with zero Young's modulus) were utilized. For the voids, their geometries were varied to cover spherical and elliptical shapes with several aspect ratios (0.2-0.4-0.65-0.75-0.9-1), volume fractions (0-0.1-0.2-0.3-0.35-0.4-0.5-1), and orientations (0-30-60-90 degrees). This model helps researchers to determine the composite modulus of elasticity using one significant and accurate expression without using numerical analysis.

关键词： modulus of elasticity Compression Composite Regression Tabu search

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Comparative Evaluation of Flexural Strength and modulus of elasticity of Three Adhesive Luting Cements at Different Time Intervals under Oral Simulated Conditions: An In Vitro Study

Dental Journal of Advance Studies

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Dental Journal of Advance Studies 2021年第2期9卷 70-76页

作者： Sumedha Dewan Tarun Kalra Manjit Kumar Ajay Bansal Abhishek Avasthi Department of Prosthodontics Bhojia Dental College and Hospital Solan Himachal Pradesh India

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Estimating modulus of elasticity (MOE) of Particleboards Using Artificial Neural Networks to Reduce Quality Measurements and Costs

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DRVNA INDUSTRIJA 2019年第3期70卷 257-263页

作者： Kurt, Rifat Karayilmazlar, Selman Bartin Univ Fac Forestry Dept Forest Ind Engn TR-74100 Bartin Turkey

There are a large number of costs that enterprises need to bear in order to produce the same product at the same quality for a more affordable price. For this reason, enterprises have to minimize their expenses through a couple of measures in order to offer the same product for a lower price by minimizing these costs. Today, quality control and measurements constitute one of the major cost items of enterprises. In this study, the modulus of elasticity values of particleboards were estimated by using Artificial Neural Networks (ANN) and other mechanical properties of particleboards in order to reduce the measurement costs in particleboard enterprises. In addition to that, the future values of modulus of elasticity were also estimated using the same variables with the purpose of monitoring the stale of the process. For this purpose, data regarding the mechanical properties of the boards were randomly collected from the enterprise for three months. The sample size (n) was: 6 and the number of samples (m): 65 and a total of 65 average measurement values were obtained for each mechanical property. As a result of the implementation, the low Mean Absolute Percentage Error (MAPE), Mean Absolute Deviation (MAD) and Mean Squared Error (AfSE) performance measures of the model clearly showed that some quality characteristics could easily be estimated by the enterprises without having to make any measurements by ANN.

关键词： estimate modulus of elasticity particleboard ANN

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DISTRIBUTIONS OF modulus of elasticity AND modulus OF RUPTURE IN FOUR MILL-RUN LUMBER POPULATIONS

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WOOD AND FIBER SCIENCE 2019年第2期51卷 183-192页

作者： Owens, Frank C. Verrill, Steve P. Shmulsky, Rubin Ross, Robert J. Mississippi State Univ Dept Sustainable Bioprod Mississippi State MS 39762 USA USDA Forest Prod Lab Madison WI 53726 USA

The modulus of elasticity (MOE) and modulus of rupture (MOR) of graded lumber populations are commonly modeled by normal, lognormal, or Weibull distributions, but recent research has cast doubt on the appropriateness of these models. Such modeling has implications for ultimate performance and efficiency of resource use. It has been shown mathematically that the distribution of MOR in a graded subpopulation does not have the same theoretical form as the full, ungraded (or "mill-run") population from which it was drawn;rather, its form is pseudo-truncated, exhibiting thinned tails. Although the phenomenon of pseudo-truncation in graded populations has been well substantiated, the form of the underlying full distribution-an essential factor in characterizing the distribution of the graded population-remains unsettled. The objective of this study was to characterize the distributions of both MOE and MOR in four diverse mill-run lumber populations to determine if and to what extent the distributions of strength and stiffness in mill-run lumber are similar from mill to mill. The authors collected a mill-run sample of 200 southern pine 2 x 4 specimens from each of four sawmills, for a total of 800 test pieces. After measuring MOE and MOR, they fit candidate distributions to those data by mill and evaluated each distribution for goodness of fit. Results suggest that perhaps none of the traditional distributions of normal, lognormal, or Weibull is adequate to model MOE or MOR across all four mills;rather, MOE and MOR in full lumber populations might be better modeled by skew normal or mixed normal distributions.

关键词： Full lumber population mill run modulus of elasticity modulus of rupture normal distribution Weibull pseudo-truncated

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Prediction of Uniaxial Compressive Strength and modulus of elasticity in Calcareous Mudstones Using Neural Networks, Fuzzy Systems, and Regression Analysis

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PERIODICA POLYTECHNICA-CIVIL ENGINEERING 2019年第1期63卷 104-114页

作者： Mahdiabadi, Naser Khanlari, Gholamreza Bu Ali Sina Univ Engn Geol Dept Geol Fac Sci Mahdieh Ave Hamadan *** Iran

The uniaxial compressive strength (UCS) and modulus of elasticity (E) are two important rock geomechanical parameters that are widely used in rock engineering projects such as tunnels, dams, and rock slope stability. Since the acquisition of high-quality core samples is not always possible, researchers often indirectly estimate these parameters. In the present study, prediction of UCS and E was investigated in calcareous mudstones of Aghajari Formation using multiple linear regression (MLR), multiple nonlinear regression (MNLR), artificial neural networks (ANN), and adaptive neuro-fuzzy inference system (ANFIS). For this purpose, 80 samples from calcareous mudstones were subjected to the point loading, block punch, and cylinder punch tests. The performance of developed models was assessed based on determination coefficients (R-2), mean absolute percentage error (MAPE), and variance accounted for (VAF) indices. The comparison of the obtained results revealed that, among the studied methods, ANFIS is the most suitable one for predicting UCS and E. Moreover, the results showed that ANN and MLNR respectively predict UCS and E better than MLR and a meaningful relationship between the observed and estimated UCS values in all regressions.

关键词： uniaxial compressive strength modulus of elasticity ANFIS ANNs MLR MNLR

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Study of prediction equation for modulus of elasticity of normal strength and high strength concrete in Taiwan

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JOURNAL OF THE CHINESE INSTITUTE OF ENGINEERS 2020年第7期43卷 638-647页

作者： Hu, Wei-Hsiu Liao, Wen-Cheng Natl Taiwan Univ Dept Civil Engn 1Sec 4Roosevelt Rd Taipei 10617 Taiwan

The modulus of elasticity of concrete (E-c) is an important factor in the design of RC structures.E(c)is also essential for engineers to estimate deflections and stiffness of RC members. The prediction and calculation ofE(c)in Taiwan are still referred to ACI318-14 or ACI363R-92. It was confirmed thatE(c)is usually overestimated due to smaller coarse aggregate amount and higher paste volume in Taiwan. To obtain preciseE(c), it is necessary to develop prediction equations that can reflect material characteristic of Taiwan. This study collects 1389 test data sets ofE(c)in Taiwan. By regression analysis with certain key parameters, such as silica fume, new and practical prediction equations based on ACI318-14 and ACI363R-92 are proposed. The proposed estimation formula improves the average value and the standard deviation ofE(c-predict)- to-E(c-test)ratio of normal-strength concrete from 122% to 99%, and from 0.173 to 0.139, respectively;Similar observation can also be found relative to high-strength concrete (The average value ofE(c-predict)- to-E(c-test)ratio of high-strength improves from 132% to 101%, and the standard deviation fell from 0.149 to 0.11). These equations reflect the lowE(c)characteristics in Taiwan and can provide a more accurate estimation ofE(c)for normal-strength and high-strength RC member designs.

关键词： Normal and high strength concrete modulus of elasticity compressive strength silica fume

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Evaluation of modulus of elasticity and modulus of rupture of full-size wood composite panels supported on two nodal-lines using a vibration technique

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CONSTRUCTION AND BUILDING MATERIALS 2019年 218卷 64-72页

作者： Guan, Cheng Liu, Jinhao Zhang, Houjiang Wang, Xiping Zhou, Lujing Beijing Forestry Univ Sch Technol Beijing 100083 Peoples R China Beijing Forestry Univ Joint Int Res Inst Wood Nondestruct Testing & Eva Beijing 100083 Peoples R China Beijing Forestry Univ Forestry & Environm Special Equipment Res Ctr Beijing 100083 Peoples R China US Forest Serv USDA Forest Prod Lab Madison WI 53726 USA

The objective of this study was to determine the feasibility of using a transverse free vibration testing method to nondestructively evaluate the bending stiffness and strength of full-size (1220 x 2440 mm) wood composite panels (WCPs). Based on the principle of transverse free vibration of a thin plate, the dynamic modulus of elasticity (MOE) of a full-size WCP supported on two nodal-lines was derived using the Rayleigh method. Transverse free vibration test was conducted on 54 full-size medium density fiberboard (MDF) panels and 36 full-size particleboard (PB) panels under a two-nodal-line support. The modulus of elasticity (MOE) and modulus of rupture (MOR) of the panels were then determined by conducting static bending tests on the small samples cut from each panel. The results indicated that the transverse free vibration of a full-size panel supported on two nodal-lines was a valid testing approach for rapid determination of dynamic modulus of elasticity of full-size MDF and PB panels. Strong linear relationships were found between the dynamic MOE of full-size panels and static MOE of small samples, with the dynamic MOE approximately 8% higher than the static MOE. In addition, the two-variate models with dynamic MOE and thickness as predicting variables and the three-variate models with natural frequency, density and thickness as variables were found both effective in predicting the modulus of rupture of full-size MDF and PB panels. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Full-size wood composite panel Medium density fibreboard modulus of elasticity modulus of rupture Particleboard Two-nodal-line support Transverse free vibration

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Modeling and prediction of modulus of elasticity of laminated veneer lumber based on laminated plate theory

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CONSTRUCTION AND BUILDING MATERIALS 2019年 196卷 437-442页

作者： Wei, Peixing Wang, Brad Jianhe Wan, Xiaojun Chen, Xiaohan Jiangsu Vocat Coll Agr & Forestry Sch Landscape Architecture Jurong 212400 Peoples R China Ningbo Sinocanada Low Carbon Technol Inst Ninghai 315600 Peoples R China

To better guide the manufacturing and application of laminated veneer lumber (LVL), a theoretical model to describe the formation of the modulus of elasticity for LVL based on the laminated plate theory is described in this work. An experiment was designed to validate the model. The results showed that the theoretical prediction agreed with the measured value. The contribution of glue to the resinated veneer mainly depended on the glue solid spread (GS) and veneer thickness, namely, for a GS of 50 g/m(2), the glue effect can be ignored when the veneer thickness was more than 1.2 mm. However, for a GS of 90 g/m(2), the veneer thickness must be more than 2.1 mm to ignore the glue effect. From the standpoint of engineering applications, the tensile and bending moduli of LVL can be considered as equal. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： Laminated plate theory Laminated veneer lumber modulus of elasticity Prediction Validation

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