Journal articles on the topic 'Models of rupture (MOR)'
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Tiryaki, Sebahattin, Uğur Aras, Hülya Kalaycıoğlu, Emir Erişir, and Aytaç Aydın. "Predictive Models for Modulus of Rupture and Modulus of Elasticity of Particleboard Manufactured in Different Pressing Conditions." High Temperature Materials and Processes 36, no. 6 (July 26, 2017): 623–34. http://dx.doi.org/10.1515/htmp-2015-0203.
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AbstractDetermining the mechanical properties of particleboard has gained a great importance due to its increasing usage as a building material in recent years. This study aims to develop artificial neural network (ANN) and multiple linear regression (MLR) models for predicting modulus of rupture (MOR) and modulus of elasticity (MOE) of particleboard depending on different pressing temperature, pressing time, pressing pressure and resin type. Experimental results indicated that the increased pressing temperature, time and pressure in manufacturing process generally improved the mechanical properties of particleboard. It was also seen that ANN and MLR models were highly successful in predicting the MOR and MOE of particleboard under given conditions. On the other hand, a comparison between ANN and MLR revealed that the ANN was superior compared to the MLR in predicting the MOR and MOE. Finally, the findings of this study are expected to provide beneficial insights for practitioners to better understand usability of such composite materials for engineering applications and to better assess the effects of pressing conditions on the MOR and MOE of particleboard.
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Høibø, Olav, and Geir I. Vestøl. "Modelling the variation in modulus of elasticity and modulus of rupture of Scots pine round timber." Canadian Journal of Forest Research 40, no. 4 (April 2010): 668–78. http://dx.doi.org/10.1139/x10-021.
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Recovery from the forest-wood chain is directly influenced by how different qualities of logs are used. Logs used directly as load-carrying members in structures are products in which MOE (modulus of elasticity when bending) and MOR (modulus of rupture) are of great importance. To achieve a more optimal bucking process in the forest, models that enable such presorting of logs for quality are desirable. In all, 533 logs from 150 trees were sampled from 10 stands with different site indices and altitudes in southern Norway. Models were developed that predicted MOE and MOR by using different stand and tree characteristics. The MOR models were compared with a model including MOE alone and a model including both MOE and different tree characteristics. The study showed that it may be a good option to combine different tree and stand characteristics with MOE. MOE and the single-tree variables diameter at breast height and mean annual ring width at breast height most reduced the residual variance when MOR was modelled. The study also showed that it is possible to perform a coarse sorting by simple stand and single-tree characteristics.
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Villasante, Antonio, Guillermo Íñiguez-González, and Lluis Puigdomenech. "Comparison of various multivariate models to estimate structural properties by means of non-destructive techniques (NDTs) in Pinus sylvestris L. timber." Holzforschung 73, no. 4 (April 24, 2019): 331–38. http://dx.doi.org/10.1515/hf-2018-0103.
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AbstractThe predictability of modulus of elasticity (MOE), modulus of rupture (MOR) and density of 120 samples of Scots pine (Pinus sylvestrisL.) were investigated using various non-destructive variables (such as time of flight of stress wave, natural frequency of longitudinal vibration, penetration depth, pullout resistance, visual grading and concentrated knot diameter ratio), and based on multivariate algorithms, applying WEKA as machine learning software. The algorithms used were: multivariate linear regression (MLR), Gaussian, Lazy, artificial neural network (ANN), Rules and decision Tree. The models were quantified based on the root-mean-square error (RMSE) and the coefficient of determination (R2). To avoid model overfitting, the modeling was built and the results validated via the so-called 10-fold cross-validation. MLR with the “greedy method” for variable selection based on the Akaike information metric (MLRak) significantly reduced the RMSE of MOR and MOE compared to univariate linear regressions (ULR). However, this reduction was not significant for density prediction. The predictability of MLRak was not improved by any other of the tested algorithms. Specifically, non-linear models, such as multilayer perceptron, did not contribute any significant improvements over linear models. Finally, MLRak models were simplified by discarding the variables that produce the lowest RMSE increment. The resulted models could be even further simplified without significant RMSE increment.
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Vincent, Manon, and Isabelle Duchesne. "Modeling flexural properties in white spruce (Picea glauca) and jack pine (Pinus banksiana) plantation trees." Canadian Journal of Forest Research 44, no. 1 (January 2014): 82–91. http://dx.doi.org/10.1139/cjfr-2013-0312.
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Mixed models combining random coefficient effect and covariance patterns were used to investigate mechanical property variations in jack pine (Pinus banksiana Lamb.) and white spruce (Picea glauca (Moench) Voss) trees. Modulus of elasticity (MOE) and modulus of rupture (MOR) were measured by conducting three-point bending tests on small defect-free samples selected from different radial positions and at a height of 2.5 m above ground within the stems. The objective of the paper was to build statistical predictive models describing the radial variations in stems for wood mechanical properties using easily measurable explanatory variables that are typically available in the wood manufacturing industry: distance from pith, tree height and diameter, and spacing. The explanatory variables integrated into the models explained MOE adequately, whereas MOR appeared harder to predict with only these variables and at this resolution. For white spruce, the best mixed-effects models explained 80% and 61% of the variation in MOE and MOR, respectively. For jack pine, it was 51% and 33% for the same response variables. These results are a step toward models that could be used in sawing simulation software designed to estimate the internal properties of sawlogs and, as a result, better predict lumber and pulp chip quality.
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Su, Zihua, Zhilin Jiang, Yi Liang, Bingzhen Wang, and Jianping Sun. "An artificial neural network model for predicting mechanical strength of bamboo-wood composite based on layups configuration." BioResources 17, no. 2 (April 25, 2022): 3265–77. http://dx.doi.org/10.15376/biores.17.2.3265-3277.
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The transportation application of the bamboo–wood composite container flooring (BWCCF) has increased considerably. However, materials would be destroyed in the process of common mechanical evaluation, resulting in a waste of resources. Therefore, this paper aims to design artificial neural network (ANN) models to predict mechanical strength of BWCCF. The modulus of rupture (MOR) and the modulus of elasticity (MOE) of BWCCF were predicted by ANN models based on layups configuration, including directions, densities, and thicknesses of 21-layer BWCCF in each layer. According to results, the mean absolute percentage errors (MAPE) and the correlation coefficient (R) were determined as 16.93% and 0.619 in prediction of MOR, and 10.10% and 0.709 in prediction of MOE, respectively. The results indicated that ANN can be applied to predict mechanical properties of BWCCF.
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Mansfield, Shawn D., Lazaros Iliadis, and Stavros Avramidis. "Neural network prediction of bending strength and stiffness in western hemlock (Tsuga heterophylla Raf.)." Holzforschung 61, no. 6 (November 1, 2007): 707–16. http://dx.doi.org/10.1515/hf.2007.115.
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Abstract The stiffness and strength, modulus of elasticity (MOE) and modulus of rupture (MOR), as well as density, moisture content, microfibril angle and diffraction pattern coefficient of variation of azimuthal intensity profile (ICV) was determined for 259 small clear specimens. These samples represent 38 old- and second-growth western hemlock (Tsuga heterophylla) trees harvested from several sites in coastal British Columbia, Canada. The data were analyzed by classic statistical regression techniques to reveal interrelations among the mechanical properties and the inherent wood properties. Simultaneously, the predictive power of artificial neural networks was evaluated with the same data set by employing several optimization techniques. Regression analysis of wood density and the flexural strength properties resulted in R2 of 0.172 and 0.332 for MOE and MOR, respectively. The most efficient network model proved to be far superior demonstrating correlation coefficients with models for MOE ranging between 0.693 and 0.750, and the corresponding MOR models ranging between 0.438 and 0.561 in all testing phases. It is apparent that neural networks have the potential and capacity to self-train and become powerful adaptive systems that can predict the strength and stiffness of wood samples. The neural network analysis also revealed the importance level of each independent variable on both MOE and MOR properties.
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Jia, Ru, Yurong Wang, Rui Wang, and Xu Chen. "Physical and Mechanical Properties of Poplar Clones and Rapid Prediction of the Properties by Near Infrared Spectroscopy." Forests 12, no. 2 (February 10, 2021): 206. http://dx.doi.org/10.3390/f12020206.
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In order to understand the physical and mechanical properties of poplar clones, and explore a method for their quick evaluation, the air dry density, modulus of rupture (MOR), modulus of elasticity (MOE), and compressive strength parallel to grains of three new bred poplar clones were explored and the prediction models with the highest accuracy were established by near infrared spectroscopy (NIRs). Clone 50 (Populus deltoides CL. ‘55/65′) had the highest air dry density, MOR, MOE, and compressive strength parallel to grains in the three clones. For clone 50 and 108 (Populus euramericana cv. ‘Guariento’), the mechanical properties of sapwood were better than those of heartwood, and the sapwood of clone 50 also had a better air dry density than that of heartwood. There were significant positive correlations between the air dry density and mechanical properties, with correlation coefficients above 0.68. Prediction models with better effects could be obtained by using information on the cross section for the air dry density and mechanical properties. First derivative+ Savitzky–Golay (S-G) smoothing methods were employed for the air dry density and MOR, and multiple scattering correction (MSC)+ S-G smoothing methods were used when establishing prediction models of MOE and compressive strength parallel to grains.
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Matoba, Tetsuya, Kei Sato, and Kensuke Egashira. "Mouse models of plaque rupture." Current Opinion in Lipidology 24, no. 5 (October 2013): 419–25. http://dx.doi.org/10.1097/mol.0b013e3283646e4d.
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Torquato, Luciane Paes, David Auty, Roger E. Hernández, Isabelle Duchesne, David Pothier, and Alexis Achim. "Black spruce trees from fire-origin stands have higher wood mechanical properties than those from older, irregular stands." Canadian Journal of Forest Research 44, no. 2 (February 2014): 118–27. http://dx.doi.org/10.1139/cjfr-2013-0164.
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In the eastern Canadian boreal forest, long fire return intervals lead to over 60% of stands having an irregular, uneven-aged structure, which is associated with slower growth. The aim of this study was to examine the effect of stand structure on the clear wood mechanical properties of black spruce (Picea mariana (Mill.) B.S.P.). A total of 128 trees were destructively sampled from stands of regular and irregular structure across Quebec, Canada. Nonlinear mixed-effects models were developed for each stand type to describe the variation in modulus of elasticity (MOE) and modulus of rupture (MOR) in small defect-free samples as functions of cambial age and annual ring width. Mechanical properties were strongly related to cambial age, with a smaller influence of ring width. After accounting for these variables, both MOE and MOR were higher in samples from stands of regular structure, although differences were less pronounced in the upper stem compared with breast height. The fixed effects of the models explained between 34% and 53% of the variation in mechanical properties. A higher incidence of mild compression wood in trees of layer origin may explain the observed differences between stand structures.
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Li, Chunxu, Yaoxiang Li, Yanzheng Zhao, Zheyu Zhang, and Zichun Wang. "Mechanical Property Prediction of Larix gmelinii Wood Based on Vis-Near-Infrared Spectroscopy." Forests 13, no. 12 (November 25, 2022): 1995. http://dx.doi.org/10.3390/f13121995.
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Larix gmelinii is the major tree species in Northeast China. The wood properties of different Larix gmelinii are quite different and under strong genetic controls, so it can be better improved through oriented breeding. In order to detect the longitudinal compressive strength (LCS), modulus of rupture (MOR) and modulus of elasticity (MOE) in real-time, fast and non-destructively, a prediction model of wood mechanical properties with high precision and stability is constructed based on visible-near-infrared spectroscopy (Vis-NIRS) technology. The featured wavelengths were selected with the algorithms of competitive adaptive reweighted sampling (CARS), successive projection algorithm (SPA), uninformative variable elimination (UVE), synergy interval partial least squares (SiPLS) and their combinations. The prediction models were then developed based on the partial least square regression (PLSR). The predictive ability of models was evaluated with coefficient of determination (R2) and root mean square error (RMSE). It indicated that CARS performed the best among the four methods examined in terms of wavelength-variable selection. The combined featured wavelength selecting method of SiPLS-CARS showed better performance than the single wavelength selection method. The optimal models of LCS, MOR and MOE are the SiPLS-CARS-PLSR model, with the R2 of the calibration set and the validation set are both greater than 0.99, and RMSE the smallest. The NIR optimal models for wood mechanical properties predictions has high predictive accuracy and good robustness.
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Mancini, Manuela, Elena Leoni, Michela Nocetti, Carlo Urbinati, Daniele Duca, Michele Brunetti, and Giuseppe Toscano. "Near infrared spectroscopy for assessing mechanical properties of Castanea sativa wood samples." Journal of Agricultural Engineering 50, no. 4 (November 27, 2019): 191–97. http://dx.doi.org/10.4081/jae.2019.953.
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Near infrared spectroscopy (NIR) is a technique widely used for the prediction of different chemical-physical features of wood. In this study, the technique was used to assess its potential to predict the mechanical characteristics of wood. Castanea sativa samples of three different European provenances were collected and laboratory tests were performed to assess the mechanical properties of wood samples. Modulus of elasticity (MOE), load-deflection curve and modulus of rupture (MOR) were calculated by using INSTRON machine with three points bending strength with elastic modulus, while density (D) was calculated according to the current standard. Samples were then analysed by means of NIR spectroscopy. The raw spectra were pre-processed and regression models were developed. Variables selection techniques were used to improve the model performance. In detail, MOE regression model returned an error of 696.01 MPa (R2=0.78). Instead, MOR and D prediction models must be further investigated on a wider number of samples considering the high variability in physical characteristics of chestnut wood. The results demonstrated the possibility to use NIR technique for the prediction of the mechanical properties of wood providing useful indications in evaluation-screening processes. Indeed, the presence of the principal wood compounds (cellulose, hemicellulose and lignin) and their influence in the characterisation of mechanical stress reactions were confirmed.
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Tong, Li, and Wenbo Zhang. "Using Fourier Transform Near-Infrared Spectroscopy to Predict the Mechanical Properties of Thermally Modified Southern Pine Wood." Applied Spectroscopy 70, no. 10 (July 20, 2016): 1676–84. http://dx.doi.org/10.1177/0003702816644453.
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This study seeks to estimate the mechanical properties of thermally modified wood (TMW) using near-infrared (NIR) spectroscopy to measure 80 samples in three-point bending tests. Near-infrared spectra collected from the transverse, radial, and tangential sections of wood, coupled with chemometric techniques, were used to predict the mechanical properties of southern pine wood, from which NIR models were constructed based on partial least squares and corresponding cross-validation. The coefficient of determination between NIR transverse section spectra, as well as two mechanical properties of wood samples, modulus of rupture (MOR) and modulus of elasticity (MOE), were above 0.92 and greater than values for other sections. Spectral data from the transverse sections were richer than data from other sections, and thus, a model based on transverse sections better predicts the mechanical properties of wood. A close relationship between the values for mechanical properties (MOE and MOR) and the NIR spectra of thermally modified southern pine wood can be demonstrated, which provides the potential to predict the mechanical properties of untreated and thermally modified wood.
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Mascarenhas, Fernando J. R., Alfredo M. P. G. Dias, and André L. Christoforo. "Analysis of the Influence of Microwave Treatment Parameters of Wood." Forests 14, no. 2 (January 19, 2023): 194. http://dx.doi.org/10.3390/f14020194.
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Microwave (MW) treatment is an effective method in the wood modification field. It has become more popular in the past decade since it enhances wood permeability, allowing a more efficient impregnation of preservative chemicals. Due to the number of parameters involved in the MW treatment of wood, multiple regression models and statistical analysis can effectively evaluate the relationship between various parameters. Therefore, this work aimed to evaluate the effects that the isolated and combined parameters of the MW treatment had on the variations of the flexural modulus of rupture (MOR) after wood specimens were MW-treated. The analyzed variables and their respective data were obtained from works on the use of MW technology for wood treatment present in the literature. Even faced with the reduced database, sufficient information was available to be used and important and accurate results were drawn. Based on the ANOVA results, wood density, initial moisture content (IMC), MW applied energy, and the product between MW power and exposure time were considered significant and could distinctly explain the reductions in the MOR values of MW-treated wood samples.
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Jiang, Zhilin, Yi Liang, Zihua Su, Aonan Chen, and Jianping Sun. "Nondestructive Testing of Mechanical Properties of Bamboo–Wood Composite Container Floor by Image Processing." Forests 12, no. 11 (November 8, 2021): 1535. http://dx.doi.org/10.3390/f12111535.
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The bamboo–wood composite container floor (BWCCF) has been wildly utilized in transportation in recent years. However, most of the common approaches of mechanics detection are conducted in a time-consuming and resource wasting way. Therefore, this paper aims to provide a frugal and highly efficient method to predict the short-span shear stress, the modulus of rupture (MOR) and the modulus of elasticity (MOE) of the BWCCF. Artificial neural network (ANN) models were developed and support vector machine (SVM) models were constructed for comparative study by taking the characteristic parameters of image processing as input and the mechanical properties as output. The results show that the SVM models can output better values than the ANN models. In a prediction of the three mechanical properties by SVMs, the correlation coefficients (R) were determined as 0.899, 0.926, and 0.949, and the mean absolute percentage errors (MAPE) were obtained, 6.983%, 5.873%, and 4.474%, respectively. The performance measures show the strong generalization of the SVM models. The discoveries in this work provide new perspectives on the study of mechanical properties of the BWCCF combining machine learning and image processing.
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Mohammadabadi, Mostafa, Vikram Yadama, and Jian Geng. "Creep behavior of 3D core wood-strand sandwich panels." Holzforschung 72, no. 6 (June 27, 2018): 513–19. http://dx.doi.org/10.1515/hf-2017-0088.
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AbstractA preliminary experimental evaluation of duration of load and creep effects of lightweight wood-strand sandwich panels (lwW-SSP) was conducted following ASTM D6815-09 to determine the equivalence to the duration of load and creep effects of visually graded lumber as specified in Practice D245. The modulus of rupture (MOR) of lwW-SSP was obtained using four-point bending tests to evaluate their creep and load behavior at three stress levels (15, 40 and 65% of MOR). Two different widths were considered to observe the effect of this parameter. lwW-SSP preformed well under long-term loads, as tertiary creep was not observed at all stress levels and the strain rate decreased over time. The panels met the criteria specified in the standard. None of the specimens failed, the creep rate decreased and the fractional deflection was <2. Accordingly, the duration of load factors of visually graded lumber is applicable to these panels. For the theoretical evaluation of solid wood behavior, viscoelastic models can also be applied to describe the creep behavior of lwW-SSP with wood-strand corrugated cores. An exponential viscoelastic model consisting of five elements accurately approximates the experimental creep behavior of three-dimensional (3D) core sandwich panel.
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Fernández-Serrano, Álvaro, and Antonio Villasante. "Modulus of rupture prediction in Pinus sylvestris with multivariate models constructed with resonance, ultrasound, and wood heterogeneity variables." BioResources 17, no. 1 (December 17, 2021): 1106–19. http://dx.doi.org/10.15376/biores.17.1.1106-1119.
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Multivariate models with multiple linear regression (MLR), artificial neural network (ANN), and k-nearest neighbors (KNN) were developed to predict the modulus of rupture of Pinus sylvestris structural timber. The aim of this study was to develop and compare these models obtained from resonance and ultrasound tests, static modulus of elasticity tests, and different measured wood feature. Resonance tests were performed in the three vibration modes (edgewise, flatwise, and longitudinal) to obtain the fundamental resonant frequencies. To compare the goodness-of-fit of the different models, the 10-fold cross-validation method was used, which proved to be an adequate strategy to avoid overfitting. The variable with the best predictive capacity of the modulus of rupture was knottiness. The error was notably lower in the multivariate than the univariate models. The ANN and KNN algorithms showed no improvement over the MLR. The most suitable MLR for prediction of the modulus of rupture was the model with four variables: knottiness, edgewise dynamic modulus of elasticity, velocity of ultrasounds, and longitudinal resonant frequency.
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Hsieh, Ming-Chi, Ke-Chang Hung, Jin-Wei Xu, Yi-Hung Wu, Wen-Shao Chang, and Jyh-Horng Wu. "Characterization and Prediction of Mechanical and Chemical Properties of Luanta Fir Wood with Vacuum Hydrothermal Treatment." Polymers 15, no. 1 (December 28, 2022): 147. http://dx.doi.org/10.3390/polym15010147.
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Since the chemical composition of wood is closely related to its mechanical properties, chemical analysis techniques such as near-infrared (NIR) spectroscopy provide a reasonable non-destructive method for predicting wood strength. In this study, we used NIR spectra with principal component analysis (PCA) to reveal that vacuum hydrothermal (VH) treatment causes degradation of hemicellulose as well as the amorphous region of cellulose, resulting in lower hydroxyl and acetyl group content. These processes increase the crystallinity of the luanta fir wood (Cunninghamia konishii Hayata), which, in turn, effectively increases its compressive strength (σc,max), hardness, and modulus of elasticity (MOE). The PCA results also revealed that the primary factors affecting these properties are the hemicellulose content, hydroxyl groups in the cellulose amorphous region, the wood moisture content, and the relative lignin content. Moreover, the ratios of performance deviation (RPDs) for the σc,max, shear strength (σs,max), hardness, and modulus of rupture (MOR) models were 1.49, 1.24, 1.13, and 2.39, indicating that these models can be used for wood grading (1.0 < RPD < 2.5). Accordingly, NIR can serve as a useful tool for predicting the mechanical properties of VH-treated wood.
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Via, Brian K., Chi-Leung So, Todd F. Shupe, Lori G. Eckhardt, Michael Stine, and Leslie H. Groom. "Prediction of Wood Mechanical and Chemical Properties in the Presence and Absence of Blue Stain Using Two near Infrared Instruments." Journal of Near Infrared Spectroscopy 13, no. 4 (August 2005): 201–12. http://dx.doi.org/10.1255/jnirs.538.
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The objective of this research was to (a) determine if blue stain in solid wood influenced calibration equations developed from a non-stained wood population, (b) assess the bias introduced when scanning was performed by the slave instrument without calibration transfer from the master instrument and (c) partition absorbance-based variation by instrument, stain and instrument × stain interaction. The results helped to determine the calibration transfer needed for this case. The dependent variables assessed from clear and stained wood were lignin, extractives, modulus of elasticity (MOE), modulus of rupture (MOR) and density When the master instrument was used for both calibration and prediction, it was found that stain-insensitive equations for the five traits could be built. However, when a slave near infrared instrument was introduced without calibration transfer, three out of five predicted traits were significantly biased by the presence of stain. Further analysis revealed an interaction between stain and instrument indicating that instrument bias was also introduced during scanning with a slave. For both multiple linear regression (MLR) and principal components regression (PCR), it was found that if a trait needed more wavelengths (or principal components) for prediction of the dependent variable, bias due to blue stain became increasingly prominent. PCR was found to perform better than MLR when stain was introduced with no calibration transfer. Such a finding alludes that PCR works better than MLR under extrapolation conditions but is not intended to support a lack of calibration transfer. Finally, the Mallows Cp diagnostic proved valuable in model selection although the well-known requirement of ( Cp – p ≤ 0) appeared conservative. For MLR and PCR, a Cp – p ≤ 5 often yielded applicable models while Cp – p > 7 was about the threshold where model performance dropped.
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Tupciauskas, Ramunas, Janis Rizhikovs, Martins Andzs, and Oskars Bikovens. "Influence of Manufacturing Conditions on Binder-Less Boards from Steam-Exploded Hemp Shives and Wheat Straw." Materials 15, no. 9 (April 26, 2022): 3141. http://dx.doi.org/10.3390/ma15093141.
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In the current decade, based on the European Green Deal, new challenges of the wood-based panel industry have arisen, seeking for formaldehyde-free bio-based adhesives and broadening raw lignocellulosics. In order to contribute to the potential solution to the challenges, binder-less boards of steam-exploded (SE 220 °C/2 min) hemp shives and wheat straw were investigated. The objective of this study was to find out the optimal hot-pressing conditions in terms of temperature (150–200 °C) and time (5–16 min) for the boards with three density levels (800–1000–1200 kg·m−3). An experimental design was created and the influence of the variables on binder-less panels were evaluated using a randomized central composite design of the response surface methodology. Water absorption (WA) and thickness swelling (TS) during 24 h, modulus of elasticity (MOE), and modulus of rupture (MOR) in bending test, internal bonding (IB), and Fourier-transform infrared spectroscopy were determined for the obtained boards. Each detected physical-mechanical property of the obtained boards was described by statistical models being different at each density level. The optimal conditions of the obtained binder-less boards were different depending on the raw material and density. For example, the optimal conditions of the boards from SE wheat straw with a density of 800 kg m−3 were found at T = 220 °C and t = 15 min, with the achieved properties of WA = 53%, TS = 4%, MOE = 2750 N mm−2, MOR = 15.5 N mm−2, and IB = 0.64 N mm−2. Based on the achieved properties at the optimal conditions, the boards meet the requirements of the conventional particleboard Type P3 according to EN 312.
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Tupciauskas, Ramunas, Janis Rizhikovs, Martins Andzs, and Oskars Bikovens. "Influence of Manufacturing Conditions on Binder-Less Boards from Steam-Exploded Hemp Shives and Wheat Straw." Materials 15, no. 9 (April 26, 2022): 3141. http://dx.doi.org/10.3390/ma15093141.
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In the current decade, based on the European Green Deal, new challenges of the wood-based panel industry have arisen, seeking for formaldehyde-free bio-based adhesives and broadening raw lignocellulosics. In order to contribute to the potential solution to the challenges, binder-less boards of steam-exploded (SE 220 °C/2 min) hemp shives and wheat straw were investigated. The objective of this study was to find out the optimal hot-pressing conditions in terms of temperature (150–200 °C) and time (5–16 min) for the boards with three density levels (800–1000–1200 kg·m−3). An experimental design was created and the influence of the variables on binder-less panels were evaluated using a randomized central composite design of the response surface methodology. Water absorption (WA) and thickness swelling (TS) during 24 h, modulus of elasticity (MOE), and modulus of rupture (MOR) in bending test, internal bonding (IB), and Fourier-transform infrared spectroscopy were determined for the obtained boards. Each detected physical-mechanical property of the obtained boards was described by statistical models being different at each density level. The optimal conditions of the obtained binder-less boards were different depending on the raw material and density. For example, the optimal conditions of the boards from SE wheat straw with a density of 800 kg m−3 were found at T = 220 °C and t = 15 min, with the achieved properties of WA = 53%, TS = 4%, MOE = 2750 N mm−2, MOR = 15.5 N mm−2, and IB = 0.64 N mm−2. Based on the achieved properties at the optimal conditions, the boards meet the requirements of the conventional particleboard Type P3 according to EN 312.
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Li Shi, Jun, S. Y. Zhang, and Bernard Riedl. "Multivariate modeling of MDF panel properties in relation to wood fiber characteristics." Holzforschung 60, no. 3 (May 1, 2006): 285–93. http://dx.doi.org/10.1515/hf.2006.046.
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Abstract Properties of medium density fiberboard (MDF) panels in relation to wood and fiber characteristics were investigated. Laboratory MDF panels were manufactured from raw fiber materials from black spruce [Picea mariana (Mill.) BSP.], three hybrid poplar clones (Populus spp.), two exotic larch (Larix gmelinii and Larix sibirica), and a mix of spruce, pine, and fir wood chips. The panels were evaluated for modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), linear expansion (LE), thickness swelling (TS), and water absorption (WA). These properties were analyzed as response variables. As predictor variables, various wood and fiber characteristics were measured, including wood density, pH, base buffering capacity and fiber coarseness. Multiple linear regression analysis was performed to develop functional relationships between panel properties (response variables) and wood fiber characteristics (predictor variables). Ten dummy variables were created and incorporated into the analysis to examine the effects of wood species or type on MDF panel properties. MOR was negatively related to arithmetic fine percentage. MOE was negatively affected by the percentage of small particles (>200 mesh) and wood pH. IB strength was negatively related to arithmetic fine percentage and fiber pH, but positively related to the percentage of small particles (>200 mesh). Wood density affected LE. TS was negatively affected by arithmetic mean fiber length. Arithmetic mean fiber width had a negative effect on panel WA. The presence of dummy variables in the models for MOE, IB and LE indicates that wood fiber characteristics other than those measured in this study significantly affected these panel properties. The study indicates that the refining process can play a significant role in manipulating MDF panel properties.
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Li, Yunhui, Meifeng Lv, Mingshu Lu, and Hongliang Guan. "miR-124a Involves in the Regulation of Wnt/β-Catenin and P53 Pathways to Inhibit Abdominal Aortic Aneurysm via Targeting BRD4." Computational and Mathematical Methods in Medicine 2022 (January 21, 2022): 1–11. http://dx.doi.org/10.1155/2022/9241959.
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Background. Abdominal aortic aneurysm (AAA) belongs to a progressive, gradual aortic rupture, which can lead to death without surgical intervention. The key factors regulating the occurrence and progress of AAA are not clear. Increasing studies have indicated that microRNA (miRNA) plays an important role in cancer development. miR-124a serves as a tumor suppressor in several neoplasms, and its upregulation can greatly inhibit the life activities such as malignant growth and migration of tumor cells. Aim. The objective of this study is to explore the association of miR-124a with AAA and to uncover the regulated mechanism of miR-124a on AAA progression. Methods. The specimens from the AAA patients were used for observing the miR-124a expression, and human aortic endothelial cells (hAoECs) were treated with AngII to establish the AAA cell models. The quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), CCK-8, transwell assay, flow cytometry assay, and western blot were conducted to unearth the regulation mechanism of miR-124a on AAA, and the dual-luciferase reporter assay was employed to investigate the downstream target of miR-124a. Results. miR-124a was significantly downregulated in the whole blood of the patients, and the decreased miR-124a was also observed in AAA cell models. Overexpressing miR-124a could effectively inhibit the proliferation and migration and promote the apoptosis of the AAA cells. The dual-luciferase reporter assay confirmed that BRD4 was a downstream target of miR-124a, and BRD4 upregulation could obviously reverse the effects of miR-124a on the phenotype of AAA cells. Moreover, it was found that miR-124a could regulate the activities of Wnt/β-catenin and P53 pathways via targeting the BRD4. Conclusion. Our data suggested that miR-124a could regulate the activities of Wnt/β-catenin and P53 to suppress the AAA progression via targeting the BRD4.
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Li, Ben Gui, Yun Shui Yu, Jun Min Chen, Liang Peng, and Wei Hong Zhou. "Modulus of Rupture Test and Numerical Fitting of Plybamboo Form." Advanced Materials Research 250-253 (May 2011): 939–42. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.939.
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Longitudinal and transverse modulus of rupture(MOR) tests of plybamboo form with different moisture content were performed. The results show that both longitudinal MOR and transverse MOR decrease with the increasing of the moisture content of the plybamboo form. At low moisture content stage MOR of the plybamboo form decrease linearly with the increasing of the moisture content of the plybamboo form. Curve regression equations of longitudinal and transverse MOR of plybamboo form were constructed by the method of numerical fitting, and linear regression equations at low moisture content stage were also constructed. Decline of plybamboo form strength itself and bonding invalidation lead to the decrease of MOR. The results of variance analysis and significance test of four regression equations show that all the regression equations achieve very significant level.
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Kothakota, Anjineyulu, Ravi Pandiselvam, Kaliramesh Siliveru, Jai Prakash Pandey, Nukasani Sagarika, Chintada H. Sai Srinivas, Anil Kumar, Anupama Singh, and Shivaprasad D. Prakash. "Modeling and Optimization of Process Parameters for Nutritional Enhancement in Enzymatic Milled Rice by Multiple Linear Regression (MLR) and Artificial Neural Network (ANN)." Foods 10, no. 12 (December 3, 2021): 2975. http://dx.doi.org/10.3390/foods10122975.
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This study involves information about the concentrations of nutrients (proteins, phenolic compounds, free amino acids, minerals (Ca, P, and Iron), hardness) in milled rice processed with enzymes; xylanase and cellulase produced by Aspergillus awamori, MTCC 9166 and Trichoderma reese, MTCC164. Brown rice was processed with 60–100% enzyme (40 mL buffer -undiluted) for 30 to 150 min at 30 °C to 50 °C followed by polishing for 20–100 s at a safe moisture level. Multiple linear regression (MLR) and artificial neural network (ANN) models were used for process optimization of enzymes. The MLR correlation coefficient (R2) varied between 0.87–0.90, and the sum of square (SSE) was placed within 0.008–8.25. While the ANN R2 (correlation coefficient) varied between 0.97 and 0.9999(1), MSE changed from 0.005 to 6.13 representing that the ANN method has better execution across MLR. The optimized cellulase process parameters (87.2% concentration, 80.1 min process time, 33.95 °C temperature and 21.8 s milling time) and xylanase process parameters (85.7% enzyme crude, 77.1 min process time, 35 °C temperature and 20 s) facilitated the increase of Ca (70%), P (64%), Iron (17%), free amino acids (34%), phenolic compounds (78%) and protein (84%) and decreased hardness (20%) in milled rice. Scanning electron micrographs showed an increased rupture attributing to enzymes action on milled rice.
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Korai, Hideaki. "Effects of Density Profile on Bending Strength of Commercial Particleboard." Forest Products Journal 72, no. 2 (March 1, 2022): 85–91. http://dx.doi.org/10.13073/fpj-d-21-00070.
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Abstract Face layer density is widely known to be important for increasing bending strength (i.e., modulus of rupture [MOR]), whereas outer core layer density is not regarded as such. This study reports the importance of the outer core layer density for commercial particleboards. The core and face layers were manufactured with coarse and fine particles, respectively. The coarse particles increased MOR because of the long wood fibers retained in the particle, whereas fine particles did not increase MOR because of the absence of long wood fibers. Long wood fibers in the outer core layer, as opposed to face layers, increase MOR. Moreover, the sampling position of the density profile specimen was important for the MOR. The MOR was influenced with the density profile specimens obtained near the center of the MOR specimen; thus, the low-density part near the center of the MOR specimen exerted a large influence by significantly decreasing the MOR.
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Sinaga, Ferry Indra Sakti H., and Lisa Melvi Ginting. "Pengaruh dan Interaksi antara Konsentrasi Perekat dengan Suhu Kempa Terhadap Keteguhan Patah (Modulus of Rupture) Papan Partikel Tandan Kosong Kelapa Sawit Menggunakan Perekat Asam Sitrat." RODA: Jurnal Pendidikan dan Teknologi Otomotif 1, no. 2 (September 24, 2021): 36. http://dx.doi.org/10.24114/roda.v1i2.27361.
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Particleboard is one of the materials that has been widely applied to various fields, including in the automotive sector. In the automotive sector, particle board commonly used as a material in the manufacture of the vehicle panels. Particleboard usually made using sawdust residue as the filler for the particleboard, but nowadays, researchers tried to make particleboard using another material, such as using empty palm oil bunches (EFB) which are waste product from the palm oil production process in palm oil mills.Modulus of rupture (MOR) of the particleboard is requirements that must be fulfilled based on Indonesia standards as contained in SNI 03-2015-2006 regarding particleboard. The greater the value of MOR, means better particleboard quality produced. This study aims to determine the effect of adhesive concentration and compression temperature on the MOR particleboard made from EFB.Testing process carried out based on SNI 03-2015-2006 standard regarding particle board. The test results were then analyzed using a two-way ANOVA using α = 0,05 to find out the effect between the adhesive concentration and the compression temperature and the interaction between the adhesive concentration and the compression temperature on the MOR of the particle board. The result shown that the adhesive concentration had a significant effect on MOR with an F= 3.640. The temperature of the compression has a significant effect on the MOR with the value of F= 36.879. The interaction between adhesive concentration and compression temperature has a significant effect on MOR with the value of F = 4.764.Keywords: particleboard 1; adhesive concentration 2; compression temperature 3; modulus of rupture (MOR).
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Sharma, D. "Properties of rainfall induced crusts in alluvial soils and their effect on modulus of rupture." Soil Research 23, no. 4 (1985): 627. http://dx.doi.org/10.1071/sr9850627.
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Crust and bulk soil samples, collected from a semi-arid region, were analysed for different properties. Crust samples had higher clay, silt, water dispersible silt plus clay, bulk density and cation exchange capacity (CEC) than the soil below the crust. Modulus of rupture (MOR) as determined on distributed crust material, showed better correlations with textural parameters viz. clay (r = 0.70), silt (r = 0.68), silt + clay (r = 0.82) and fine sand (r = -0.81) than with other parameters like CEC (r = 0.53), ESP (r = 0.55), exchangeable magnesium percentage (r = 0.46) and exchangeable calcium percentage (r = -0.44). Multiple linear regressions between MOR and different crust parameters showed that clay, silt and ESP accounted for 84.1% variation in MOR in these soils.
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Florian, Ioan Alexandru, Andrei Buruiana, Teodora Larisa Timis, Sergiu Susman, Ioan Stefan Florian, Adrian Balasa, and Ioana Berindan-Neagoe. "An Insight into the microRNAs Associated with Arteriovenous and Cavernous Malformations of the Brain." Cells 10, no. 6 (June 2, 2021): 1373. http://dx.doi.org/10.3390/cells10061373.
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Background: Brain arteriovenous malformations (BAVMs) and cerebral cavernous malformations (CCMs) are rare developmental anomalies of the intracranial vasculature, with an irregular tendency to rupture, and as of yet incompletely deciphered pathophysiology. Because of their variety in location, morphology, and size, as well as unpredictable natural history, they represent a management challenge. MicroRNAs (miRNAs) are strands of non-coding RNA of around 20 nucleotides that are able to modulate the expression of target genes by binding completely or partially to their respective complementary sequences. Recent breakthroughs have been made on elucidating their contribution to BAVM and CCM occurrence, growth, and evolution; however, there are still countless gaps in our understanding of the mechanisms involved. Methods: We have searched the Medline (PubMed; PubMed Central) database for pertinent articles on miRNAs and their putative implications in BAVMs and CCMs. To this purpose, we employed various permutations of the terms and idioms: ‘arteriovenous malformation’, ‘AVM’, and ‘BAVM’, or ‘cavernous malformation’, ‘cavernoma’, and ‘cavernous angioma’ on the one hand; and ‘microRNA’, ‘miRNA’, and ‘miR’ on the other. Using cross-reference search; we then investigated additional articles concerning the individual miRNAs identified in other cerebral diseases. Results: Seven miRNAs were discovered to play a role in BAVMs, three of which were downregulated (miR-18a, miR-137, and miR-195*) and four upregulated (miR-7-5p, miR-199a-5p, miR-200b-3p, and let-7b-3p). Similarly, eight miRNAs were identified in CCM in humans and experimental animal models, two being upregulated (miR-27a and mmu-miR-3472a), and six downregulated (miR-125a, miR-361-5p, miR-370-3p, miR-181a-2-3p, miR-95-3p, and let-7b-3p). Conclusions: The following literature review endeavored to address the recent discoveries related to the various implications of miRNAs in the formation and growth of BAVMs and CCMs. Additionally, by presenting other cerebral pathologies correlated with these miRNAs, it aimed to emphasize the potential directions of upcoming research and biological therapies.
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Antony, Finto, Lewis Jordan, Laurence R. Schimleck, Alexander Clark, Ray A. Souter, and Richard F. Daniels. "Regional variation in wood modulus of elasticity (stiffness) and modulus of rupture (strength) of planted loblolly pine in the United States." Canadian Journal of Forest Research 41, no. 7 (July 2011): 1522–33. http://dx.doi.org/10.1139/x11-064.
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Modulus of elasticity (MOE), modulus of rupture (MOR), and specific gravity (SG) are important properties for determining the end-use and value of a piece of lumber. This study addressed the variation in MOE, MOR, and SG with physiographic region, tree height, and wood type. Properties were measured from two static bending samples (dimensions 25.4 mm × 25.4 mm × 406.4 mm) representing each wood type (corewood and outerwood) at heights 2.4, 7.3, and 12.2 m from three trees sampled from 135 loblolly pine ( Pinus taeda L.) stands distributed across the natural range of the species. An analysis of variance was conducted to detect the effect of physiographpic region, height, and wood type on each property. Significant regional variation was observed for MOE, MOR, and SG for both wood types with high values in the Gulf and South Atlantic Coastal Plains compared with other regions. A significant height-related trend in MOE, MOR, and SG within a tree was identified; MOE and MOR increased in corewood and decreased in outerwood with height. Maps showing regional variation in MOE and MOR at different heights by wood type were produced and showed significant variation for both properties.
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Zhang, Li, and Ying Cheng Hu. "Linear Relationship between Dynamic Young’s Modulus and MOR of the Poplar LVL Reinforced with Monolayer Fiberglass Mesh." Applied Mechanics and Materials 26-28 (June 2010): 940–43. http://dx.doi.org/10.4028/www.scientific.net/amm.26-28.940.
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In this paper, the poplar LVL was reinforced with monolayer fiberglass mesh. The reinforcing effect of monolayer fiberglass mesh on improving the static bending strength (or modulus of rupture, MOR) was studied. And three different nondestructive testing (NDT) methods, such as the longitudinal transmission method, longitudinal vibration method and flexural vibration method (out-plane and in-plane), were used to test the dynamic Young’s modulus of the reinforced poplar LVL. The linear relationships were investigated between the four dynamic Young’s moduli and the MOR of the reinforced poplar LVL. It can be concluded that the three NDT methods are useful for predicting the MOR of reinforced LVL, but the flexural and longitudinal vibration methods had better accuracy to estimate the MOR.
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Ispas, Mihai, Camelia Cosereanu, Octavia Zeleniuc, and Mihaela Porojan. "Flexural properties of blockboard reinforced with glass fiber and various types of fabrics." BioResources 14, no. 4 (October 28, 2019): 9882–92. http://dx.doi.org/10.15376/biores.14.4.9882-9892.
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Flexural properties were evaluated of blockboard with spruce (Picea abies Mill) core and faces made of 2.5-mm fromager (Ceiba pentandra) veneer and 3-mm high-density fiberboard (HDF). For these two types of structures, fiber glass, jute, gauze, and cotton fabrics, were separately bonded under the face layers to improve the strength performance. Flexural properties, modulus of rupture (MOR), and modulus of elasticity (MOE) were determined under laboratory conditions. Improved values were found for MOR and MOE tested in the parallel to core grain direction compared to those perpendicular-to-grain. They were 32% to 49% (MOR) and 39% to 95% (MOE) improvements in case of veneer faces and 142% to 161% (MOR) and 134% to 245% (MOE) improvements in case of HDF faces. The best results of MOR and MOE were obtained for glass fiber used as insertion material, the higher ones being reached for specimens tested in the parallel direction to grain, which were 56.1 N/mm2 (MOR) and 6704 N/mm2 (MOE) for HDF faces. Generally, the improvements were more evident on the blockboard structures with veneer faces oriented perpendicular-to-core grain (30% for MOR and 18% MOE) and for HDF faces with parallel core grain orientation (16% for MOR and 6% MOE).
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Mihailović, Vladislava, Mira Miric-Milosavljević, Marija Djurković, Goran Mladenović, Milos Milosević, and Isaak Trajković. "Loading rate effects on MOE and MOR distributions in testing of small clear beech wood specimens." BioResources 17, no. 1 (January 26, 2022): 1818–35. http://dx.doi.org/10.15376/biores.17.1.1818-1835.
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Distributions of the modulus of elasticity (MOE) and modulus of rupture (MOR) were characterized at three loading rates for small clear beech specimens in static bending. The correlation between MOE and MOR for all three loading rates was significant, but it weakened with increasing load rates. The analysis of the characteristics of empirical distributions, as well as the preliminary selection of the theoretical distributions for MOE and MOR, were performed on the basis of L-moments and L-moment diagrams. According to the standard for testing small specimens, MOE and MOR are determined as the arithmetic mean of the sample. Usage of the arithmetic mean is justified when the analyzed quantity is symmetrically distributed. It was found that the distribution of MOE and MOR is not always symmetric. The loading rate influences the shapes of the MOE and MOR empirical distributions, and consequently the choice of theoretical distribution. The general extreme value distribution stood out as the best one for both MOE and MOR, regardless of the loading rate, and the second overall ranked distribution is the three-parameter Weibull distribution. The loading rate affected the value of the fifth percentile in MOR, when determined from both the empirical and theoretical distributions.
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Purwanto, Djoko. "SIFAT PAPAN PARTIKEL DARI SERAT TANDAN KOSONG SAWIT DAN SERBUK KAYU DENGAN PEREKAT UREA FORMALDEHIDA (The Properties of Particle Board from Oil Palm Empty Fruit Bunches Fiber Sawdust with Urea Formaldehyde Resin)." Jurnal Riset Industri Hasil Hutan 8, no. 1 (July 1, 2016): 1. http://dx.doi.org/10.24111/jrihh.v8i1.2062.
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A palm oil mill with a capacity of hundred thousand tons of fresh fruit bunches per year will produce palm fiber waste about 12,000 tons. Recently, the use of palm empty fruit bunches (OPEFB) fiber is as fuel for electricity generation in the industry. Palm fiber waste contains lignocellulose materials as a feedstock to particle board manufacture. The aim of this research is to evaluate the properties of particle board from a mixture of OPEFB fiber and sawdust. The ratio of OPEFB fiber and sawdust are 100% : 0%; 75% : 25%; 50% : 50%; 25% : 75% and 0% : 100%, plus urea formaldehyde adhesive in a concentration of 11%. The boards were pressed using a clamp pressure of 16 kg/cm2 for 15 minutes at a temperature of 110 – 120 0C. The testing methods and standards of physical properties (moisture contents, thickness swelling, density) and mechanical (modulus of elasticity/MOE, modulus of rupture/MOR, screw withdrawal and internal bond strengths) refers to the SNI. 03 – 2105 - 2006. The results showed that the particle board made from 100% OPEFB fiber produces modulus of elasticity/MOE 1594.88 kg/cm2; modulus of rupture/MOR 18.08 kg/cm2; screw withdrawal 31.34 kg/cm2 and internal bond strength 0.86 kg/cm2. The addition of sawdust for 50% can improve modulus of elasticity/MOE, modulus of rupture/MOR and internal bond strength.
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Christoforo, André L., Maria F. do Nascimento, Tulio H. Panzera, Sérgio L. M. Ribeiro Filho, and Francisco A. R. Lahr. "Homogeneous Pinus sp. particle boards reinforced with laminated composite materials." Engenharia Agrícola 36, no. 3 (June 2016): 558–65. http://dx.doi.org/10.1590/1809-4430-eng.agric.v36n3p558-565/2016.
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ABSTRACT This study aimed to evaluate the mechanical performance of laminated composite materials (fiberglass, carbon, sisal, palm fiber) in epoxy matrix as reinforcement in wood particleboards of Pinus sp. with bicomponent polyurethane resin from castor oil. Modulus of elasticity (MOE) and modulus of rupture (MOR) were investigated using a three-point bending test. Single-layered laminated plates were used to reinforce traction of specimens obtained from boards. MOE and MOR of materials developed without reinforcements exceeded limits in ABNT standards both NBR 12810-2:2002 and A208.1:199, proving therefore their feasibility. In all investigated cases, inclusion of reinforcements led to higher values for both MOE and MOR. Composites in fiberglass presented the best results.
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Baek, Seung-Youp, Yo-Jin Song, Hyun-Woo Kim, and Soon-Il Hong. "Bending strength prediction and finite element analysis of larch structural beams." BioResources 18, no. 1 (January 19, 2023): 1824–35. http://dx.doi.org/10.15376/biores.18.1.1824-1835.
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The material constants of wood required for finite element analysis (FEA) are usually calculated using small clear specimens. However, defects, such as knots and slope of grain affect the strength reduction in the full-size specimens. Consequently, an error occurs if only the material constant calculated from the small clear specimens is used to predict modulus of rupture (MOR). Therefore, in this study, the MOR reduction coefficient according to defect was obtained through the bending test of the full-size specimens and applied to the FEA, in addition to the material constant from the small clear specimens. The maximum bending moment section was measured for a 3-section four-point load, and defects in the outermost tension layer were measured for laminated timber and glulam. The result of the bending test confirmed that MOR also decreased as the size of the defect increased. Therefore, when predicting MOR, a strength reduction ratio according to visual grade was applied. The MOR predicted FEA was twice as large as the actual MOR before defect correction, but the prediction error after defect correction was greatly reduced to 8%, thus increasing the prediction accuracy.
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Dotun, Atoyebi Olumoyewa, Odeyemi Samson Olalekan, Azeez Lateef Olugbenga, and Modupe Abayomi Emmanuel. "Physical and Mechanical Properties Evaluation of Corncob and Sawdust Cement Bonded Ceiling Boards." International Journal of Engineering Research in Africa 42 (April 2019): 65–75. http://dx.doi.org/10.4028/www.scientific.net/jera.42.65.
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This study considered the production of composite ceiling boards from both agricultural and industrial wastes. Boards with different blending proportions by weight of cement, corncob and sawdust (Cem:Ccb:Swd) were produced and tested. Physical and mechanical tests such as Water Absorption (WA), Thickness Swelling (TS), Modulus of Elasticity (MOE) and Modulus of Rupture (MOR) were carried out on the products. The findings revealed that the board with Cem:Ccb:Swd blending proportion 50:10:40 gave the highest values of MOE and MOR and also had the lowest values of WA and TS. The MOE and MOR values of 3.432 are both higher than the minimum values of 550 N/mm2 and 3 N/mm2 specified for MOE and MOR respectively by the American National Standard Institute, for general-use particle boards. The cement content is inversely proportional to the physical properties and directly proportional to the mechanical properties.
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Yuan, Chengdong, Siyang Hu, and Tamara Bechtold. "Stable compact modeling of piezoelectric energy harvester devices." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 39, no. 2 (April 27, 2020): 467–80. http://dx.doi.org/10.1108/compel-07-2019-0305.
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Purpose Based on the framework of Krylov subspace-based model order reduction (MOR), compact models of the piezoelectric energy harvester devices can be generated. However, the stability of reduced piezoelectric model often cannot be preserved. In previous research studies, “MOR after Schur,” “Schur after MOR” and “multiphysics structure preserving MOR” methods have proven successful in obtaining stable reduced piezoelectric energy harvester models. Though the stability preservation of “MOR after Schur” and “Schur after MOR” methods has already been mathematically proven, the “multiphysics structure preserving MOR” method was not. This paper aims to provide the missing mathematical proof of “multiphysics structure preserving MOR.” Design/methodology/approach Piezoelectric energy harvesters can be represented by system of differential-algebraic equations obtained by the finite element method. According to the block structure of its system matrices, “MOR after Schur” and “Schur after MOR” both perform Schur complement transformations either before or after the MOR process. For the “multiphysics structure preserving MOR” method, the original block structure of the system matrices is preserved during MOR. Findings This contribution shows that, in comparison to “MOR after Schur” and “Schur after MOR” methods, “multiphysics structure preserving MOR” method performs the Schur complement transformation implicitly, and therefore, stabilizes the reduced piezoelectric model. Originality/value The stability preservation of the reduced piezoelectric energy harvester model obtained through “multiphysics structure preserving MOR” method is proven mathematically and further validated by numerical experiments on two different piezoelectric energy harvester devices.
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Schabowicz, Krzysztof, Paweł Sulik, Tomasz Gorzelańczyk, and Łukasz Zawiślak. "Assessment of the Destruction of a Fibre Cement Board Subjected to Fire in a Large-Scale Study." Materials 15, no. 8 (April 17, 2022): 2929. http://dx.doi.org/10.3390/ma15082929.
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This article presents the results of a study involving the assessment of the structural destruction of fibre cement boards taken from a large-scale model subjected to fire. These were subjected to a three-point bending test using the acoustic emission method. The analysis of the obtained results took into account the course of bending stresses σm, the modulus of rupture (MOR), the number of acoustic emission events Nzd and the sum of EA events ∑Nzd. The conducted tests showed that the samples subjected to fire exhibited a clear decrease, up to 72%, in the recorded sum of EA events compared to a reference board (not subjected to fire). The analysis of the obtained modulus of rupture (MOR) values showed a similar trend—the reduction of the modulus of rupture for the degraded samples was in the range of 66–96%. In order to illustrate the changes taking place in the structure of the tested plates more precisely, analyses were carried out using the optical method and a digital microscope. This method may be sufficient for the final evaluation of degraded samples.
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Jacques, Eric, Alan Lloyd, Abass Braimah, Murat Saatcioglu, Ghasan Doudak, and Omar Abdelalim. "Influence of high strain-rates on the dynamic flexural material properties of spruce–pine–fir wood studs." Canadian Journal of Civil Engineering 41, no. 1 (January 2014): 56–64. http://dx.doi.org/10.1139/cjce-2013-0141.
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The influence of high strain-rate loading on the flexural response of typical light-frame wood construction has been investigated. A total of 30 stud grade 38 mm × 140 mm × 2440 mm (2″ × 6″ × 8′) spruce–pine–fir (S–P–F) lumber specimens were tested within a range of low and high strain-rates between 6 × 10−6 s−1 and 0.4 s−1. A single-degree-of-freedom iterative solution procedure was used to compute the high strain-rate modulus of rupture (MOR) and modulus of elasticity (MOE). The MOR was statistically enhanced by high strain-rates, while the MOE and strain at rupture were not. Since equilibrium of the dynamic stress–strain relationship requires that one or both of the MOE and strain at rupture must be sensitive to strain-rate effects, the lack of observed rate enhancement on these material properties was attributed to large scatter within a small sample set. Based on the results, material dynamic increase factors and a stress–strain relationship suitable for blast resistant design of timber structures were also proposed.
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Aswadi, Lalu samsul, Dwi Sat Agus Yuwana, and Herlita Prawenti. "STUDI EKSPERIMENTAL MODULUS OF RUPTURE DAN MODULUS OF ELASTICITY LAMINATED VENEER LUMBER KAYU SENGON." Jurnal Rekayasa Infrastruktur Sipil 2, no. 1 (August 12, 2021): 9. http://dx.doi.org/10.31002/.v1i2.3392.
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<p><em>Paraserianthes falcataria</em> atau dikenal dengan kayu sengon merupakan spesies kayu yang cepat tumbuh tetapi memiliki kekuatan yang rendah sehingga penggunaannya dibatasi hanya untuk elemen non-struktural saja. Salah satu cara untuk meningkatkan kekuatan kayu sengon yaitu dengan teknologi LVL (<em>Laminated Veneer Lumber</em>).</p><p>Penelitian ini bertujuan untuk mendapatkan nilai <em>Modulus of Rupture</em> (MOR) dan <em>Modulus of Elasticity</em> (MOE) LVL kayu Sengon dari pengujian lentur secara eksperimental. Hasil penelitian ini diharapkan dapat memberikan sumbangan ilmiah untuk basis data sifat mekanika kayu Indonesia dan khususnya untuk perencanaan komponen struktur tekan dan lentur. Benda uji LVL kayu Sengon sebanyak 8 buah dengan dimensi 480 mm x 80 mm x 40 mm ditumpu di kedua ujungnya. Benda uji kemudian diberi beban lentur ditengah-tengah secara beangsur-angsur sampai benda uji runtuh. Kemudian dicatat berapa beban yang mampu ditahan oleh masing-masing benda uji. Dari hasil pengujian kuat lentur tersebut kemudian dihitung <em>Modulus of Rupture</em> (MOR) dan <em>Modulus of Elasticity</em> (MOE) LVL kayuSengon dari masing-masing benda uji.</p><p>Dari pengujian didapatkan hasil MOR dari 8 benda uji berturut-turut yaitu 30,08 Mpa, 39,14 Mpa, 39,14 Mpa, 33,96 Mpa, 35,90 Mpa, 38,17 Mpa, 39,78 Mpa dan 31,70 Mpa dengan nilai rata-rata MOR dari 8 benda uji adalah 35,98 Mpa. Hasil dari nilai MOE untuk 8 benda uji berturut-turut adalah 3436,36 Mpa, 3306,12 Mpa, 3306,12 Mpa, 3497,14 Mpa, 3469,88 Mpa, 3888 Mpa, 3353.23 Mpa dan 3351,72 Mpa dengan nilai rata-rata MOE dari 8 benda uji adalah 3451,07 Mpa.</p>
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Chen, Ming, and Jian Hua Lyu. "Physical and Mechanical Properties of Alnus Formosana Wood Introduced into Sichuan." Applied Mechanics and Materials 574 (July 2014): 411–15. http://dx.doi.org/10.4028/www.scientific.net/amm.574.411.
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The mechanical and physical properties of Alnus formosana wood from Sichuan, China were studied. Air-dry density, oven-dry density, basic density, shrinkage, swelling, parallel-to-grain compressive strength, parallel-to-grain tensile strength, modulus of rupture (MOR),modulus of elasticity (MOE) ,impact toughness were analyzed. Results from this study show that air-dry density, oven-dry density and basic density were respectively 0.52, 0.49 and 0.43g/cm3. The average value of volumetric shrinkage was 7.111% and the average value of volumetric swelling was 7.06%. The average values of modulus of elasticity (MOE) ,modulus of rupture (MOR), parallel-to-grain compressive strength, parallel-to-grain tensile strength and impact toughness were 8102.429 Mpa, 80.429 Mpa, 41.575Mpa, 81.542 Mpa and 47.406 Kj/m2 , respectively. This study solved a basic problem about the planting and utilization of Alnus formosana wood in Sichuan, China.
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Chang, Xin Man, Juan Wei, and Ming Jie Guan. "Bending Performance of Carbonized Bamboo Scrimber and Fracture Morphology Analysis after Different Ageing Treatments." Advanced Materials Research 744 (August 2013): 362–65. http://dx.doi.org/10.4028/www.scientific.net/amr.744.362.
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This paper described the influence of different ageing treatments on bending performance of carbonized bamboo scrimber according to three ageing standards (ASTM D1037, BS EN1087-1 and WCAMA). The modulus of elasticity (MOE) and modulus of rupture (MOR) were tested and the fracture morphology of the samples after mechanical test was also analyzed by SEM before and after ageing. The results showed that the average reduction rates of MOE and MOR were respectively 47.48% and 34.98%. In addition, SEM micrographs revealed that the fracture morphology of ASTM and BS EN presented smoother surfaces than WCAMA. The fracture surface of WCAMA was similar to Control but smoother in some parts. This was mainly due to the brittle rupture playing a dominating role in different degrees based on three ageing treatments. In conclusion, the brittleness of material after ageing was intensified leading to the decline of the bending performance.
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Chung, Min-Jay, and Sheng-Yang Wang. "Mechanical properties of oriented bamboo scrimber boards made of Phyllostachys pubescens (moso bamboo) from Taiwan and China as a function of density." Holzforschung 72, no. 2 (January 26, 2018): 151–58. http://dx.doi.org/10.1515/hf-2017-0084.
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AbstractThe properties of oriented bamboo scrimber boards (OBSB) have been investigated at three density levels (0.8, 0.9, and 1.0 g cm3), while the boards were made from moso bamboo (Phyllostachys pubescens) grown in Taiwan (T-OBSB) and China (C-OBSB). A non-destructive technique (NDT), ultrasonic-wave velocity (Vu) measurements were applied and the dynamic modulus of elasticity (MOEdyn) was calculated. Moreover, static modulus of elasticity (MOE), modulus of rupture (MOR), profile density distribution, internal bond strength (IB), springback (SB), and dimensional stability were determined based on traditional methods. Positive linear relationships between density andVu, MOEdyn, MOE and MOR were observed, no matter if the measurements were done parallel (//) or perpendicular (⊥) to the fiber direction of the OBSBs. Moreover,Vu(//), MOEdyn,u(//), MOE(//), and MOR(//)were higher thanVu(⊥), MOEdyn,u(⊥), MOE(⊥)and MOR(⊥). C-OBSB had slightly lowerVu(//),Vu(⊥), MOEdyn,u(//)and DMOEu(⊥)values than T-OBSB. T-OBSB had higher MOE(//), MOE(⊥)and MOR(//)than C-OBSB, but less MOR(⊥). The profile density distribution of high-density T-OBSB showed singnificant data scattering. The profile density distribution of C-OBSB was homogeneous at all density levels. IB and SB data are directly proportional to density, but water absorption, thickness swelling and volumetric swelling are inversely proportional to density. T-OBSB has better bonding and strength properties, and dimensional stability than C-OBSB.
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Ferro, Fabiane Salles, Diego Henrique de Almeida, Amós Magalhães de Souza, Felipe Hideyoshi Icimoto, Andre Luis Christofóro, and Francisco Antonio Rocco Lahr. "Influence of Proportion Polyol/Pre-Polymer Castor-Oil Resin Components in Static Bending Properties of Particleboards Produced with Pinus sp." Advanced Materials Research 884-885 (January 2014): 667–70. http://dx.doi.org/10.4028/www.scientific.net/amr.884-885.667.
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The aim of this research is to evaluate the influence of castor-oil based polyurethane resin formulation (particularly proportion pre-polymer/polyol) in static bending properties of particleboards produced with Pinus sp. wood specie. Results related to modulus of rupture (MOR) and modulus of elasticity were determined. Four proportions polyol/pre-polymer were evaluated: 0.75:1; 1:1; 1:1.25; 1:1.5. Results showed improvement in MOR and MOE with increase of pre-polymer component. Proportion 1:1.25 (poliol: pre-polymer) was considered the most interesting once employs the least amount of the petroleum-derived component.
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Ten Eyck, M. O., R. W. Ohnsorg, and L. E. Groseclose. "Hot Isostatic Pressing of Sintered Alpha Silicon Carbide Turbine Components." Journal of Engineering for Gas Turbines and Power 109, no. 3 (July 1, 1987): 290–97. http://dx.doi.org/10.1115/1.3240038.
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Hot isostatic pressing (HIPing) without encapsulation has been investigated with sintered alpha silicon carbide plates and Modulus of Rupture (MOR) bars made by dry pressing and with MOR bars and gas turbine rotors made by injection molding. Early HIPing trials indicated that substantial density increases up to 99.5 percent of theoretical could be achieved. At least 98 percent densification was consistently attainable on components initially having greater than 95 percent density and less than about 1 percent open porosity. Several HIPing cycles were investigated by varying maximum temperature, maximum pressure, and their respective rates. Analysis of densities, MOR bar strength and Weibull modulus, and microstructures were used to assess the influence of HIPing parameters on material properties. Vacuum spin test results and room temperature flexural strength data on MOR bars cut from HIPed rotors were compared with results from pressureless sintered rotors. Although densities and flexural strength showed improvement, data on rotor spin-test performance were inconclusive. Emphasis is now being placed on optimizing the HIPing cycle for gas turbine rotors.
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Petrović, Danijela, Vojislav Dukić Dukić, Zdravko Popović, and Nebojša Todorović. "MOR and MOE of Serbian Spruce (Picea omorika Pančić/Purkyně) Wood from Natural Stands." Drvna industrija 72, no. 2 (May 7, 2021): 193–200. http://dx.doi.org/10.5552/drvind.2021.2028.
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The paper presents the results of testing the bending stress of Serbian spruce wood from natural stands. In testing the samples, in addition to the modulus of rupture, the bending stress at the proportionality limit, the ratio between the stress at the proportionality limit and the modulus of rupture as well as the modulus of elasticity of wood were determined. The study included nine trees from natural stands, and a total of 261 samples were tested. Regression analysis determined the dependences of these mechanical properties on the annual ring width, the proportion of late wood and wood density, as well as the dependence of the modulus of elasticity on the modulus of rupture.
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Syahrir, Syahrir. "PENGARUH PENAMBAHAN PASAK TERHADAP SIFAT MEKANIK BALOK BAMBU LAMINASI DENGAN PEREKAT PATI." STABILITA || Jurnal Ilmiah Teknik Sipil 8, no. 3 (November 30, 2020): 107. http://dx.doi.org/10.55679/jts.v8i3.14799.
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Seiring dengan laju pertumbuhan penduduk yang semakin tinggi, perkembangan industri perumahan pun meningkat dari tahun ke tahun. Hal ini sangat mempengaruhi penggunaan bahan bangunan di masyarakat luas, terutama penggunaan kayu. Dengan maraknya penggunaan kayu mengakibatkan semakin menipisnya persediaan kayu legal di pasaran. Oleh karena itu, perlu dicari bahan bangunan lain pengganti kayu yang juga memiliki sifat-sifat dasar yang mirip kayu, seperti bambu.Kini pola pemanfaatan bambu yang mulai dikembangkan adalah pengolahan bambu secara laminasi, dalam pembuatan bambu laminasi, dibutuhkan bahan perekat untuk merekatkan bilah-bilah bambu sehingga menjadi balok bambu. Perekat yang digunakan dalam penelitian ini adalah pati sagu. Dengan pertimbangan beberapa negara maju sudah menolak penggunaan formaldehyde sebagai perekat pada bambu laminasi. Karena dikhawatirkan zat kimia ini dapat beraksi dengan udara luar maupun panas, sehingga dapat menjadi racun.Adapun hasil pengujian yang telah dilakukan, dapat ditarik beberapa kesimpulan antara lain : Pertama, hasil pengujian lentur balok laminasi perekat sagu antara lain: a. Hasil uji kuat lentur rata-rata balok laminasi dengan perekat sagu tanpa pasak adalah: 1) Modulus of Rupture (MOR) 109,04MPa. 2) Modulus of Elasticity (MOE) 25927,54 MPa. b. Hasil uji kuat lentur rata-rata balok laminasi perekat sagu dengan kemiringan pasak 450 adalah: 1) Modulus of Rupture (MOR) 132,94 MPa. 2) Modulus of Elasticity (MOE) 31276,95 MPa. c. Hasil uji kuat lentur rata-rata balok laminasi perekat sagu dengan kemiringan pasak 900 adalah: 1) Modulus of Rupture (MOR) 126,71 MPa. 2) Modulus of Elasticity (MOE) 29906,29 MPa. Kedua, dari hasil pengujian kuat lentur, diketahui bahwa pada pengujian balok laminasi semuanya mengalami gagal delaminasi. Gagal delaminasi pada pengujian balok laminasi ini terjadi karena nilai kuat geser balok laminasi (perekat) masih lebih kecil daripada nilai kuat geser lamina bambu.
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García-Ortuño, Teresa, Javier Andréu-Rodríguez, María T. Ferrández-García, Manuel Ferrández-Villena, and Clara E. Ferrández-García. "Evaluation of the physical and mechanical properties of particleboard made from giant reed (Arundo donax L.)." BioResources 6, no. 1 (December 26, 2010): 477–86. http://dx.doi.org/10.15376/biores.6.1.477-486.
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Single-layer experimental particleboards were made from various sizes of Arundo donax particles bonded with urea formaldehyde resin. The experimental panels were tested for their mechanical strength including modulus of rupture (MOR), modulus of elasticity (MOE), internal bonding (IB), screw holding strength (SH), and physical properties (density, moisture content, thickness swelling (TS), and water absorption (WA)) according to the procedures defined by European Union (EN) Standards. The overall results showed that most panels exceeded the EN Standards for MOE, MOR, and IB. The mechanical properties of the particleboard were enhanced as the density increased. Particle size was found to have a profound effect on the board properties.
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Zhen, Xing, Jiu Yin Pang, Shi Cheng Zhang, and Ya Zhe Jiang. "The Effect of Impregnation Process on the Performance of Veneer Composite Plank." Advanced Materials Research 239-242 (May 2011): 2411–14. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.2411.
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This study focuses on the effect of impregnation process on the main mechanical properties in the production of veneer composite plank. The results showed that:①Under the normal pressure and temperature the drug absorption of impregnated veneer shall extend the volume with the growth in impregnation time, but growing faster early, the later change slowly. In the impregnation process under pressure, its absorption rate and speed are greatly increased. ②The Modulus of rupture (MOR) and modulus of elasticity (MOE) of veneer composite plank are gradually increased with the drug absorption increased, but after reached a certain peak value they gradually decrease, and the variation of MOE is smaller than MOR.
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Strayhorn, Tyler, Phil Mitchell, and David Tilotta. "Strength Properties of Full-Size Oriented Strand Board Panels Following Submergence in Potable and Salt Water." Forest Products Journal 72, no. 1 (January 1, 2022): 58–66. http://dx.doi.org/10.13073/fpj-d-21-00058.
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Abstract One of the largest contributors to the economic loss from floods is the complete or partial destruction of residential buildings, and finding ways to eliminate or minimize this loss is important. Oriented strand board (OSB) is a wood product commonly used in home construction, so a better understanding of how flood water affects its mechanical properties is warranted. In this study, the moduli of elasticity and rupture (MOE and MOR, respectively) of representative samples removed from full-size (4 by 8-ft [1.2 by 2.4 m]) OSB panels were examined following the submergence of the panels in potable and salt water (surrogates for flood water) for increasing periods of time (i.e., 8, 24, 48, 72, 168, and 336 h). The results of our study show that after 8 hours of panel submersion in potable water, MOR and MOE is reduced by 15 percent and 16 percent, respectively; no significant change was observed in MOR and MOE for panels soaked in salt water. After 168 hours, the MOR loss was 43 percent for panels soaked in potable water and 38 percent for panels soaked in salt water. For MOE, there was a 35 percent loss regardless of water type. Submersion of panels in either water type for an additional 168 hours resulted in no significant change in MOR or MOE. The MOR and MOE of samples removed from the edges of the submerged panels, for both water types, were lower than those of the interior samples. Finally, the decreases in average MOR and MOE following submergence in either water type were approximately independent of brand.