Papers by Keyword: Correlation

Abstract: Magnesium oxide (MgO) nanoparticles were synthesized using the sol-gel technique then characterized. Cetyl Trimethyl Ammonium Bromide (CTAB) surfactant was added to reduce Van der Waal forces among MgO nanoparticles and distilled water forming a stable nanofluid using two-step method with aid of ultrasound sonication. Pure distilled water and nanofluids with different volume fractions of 0.25, 0.5, 0.75, and 1% are used as working fluids. Thermophysical properties of prepared nanofluids were measured experimentally and determined theoretically. Effect of solid volume fraction on the thermophysical properties; including thermal conductivity, heat capacity, viscosity, and density of MgO-water nanofluids are discussed. Moreover, experimental results have been compared with the suitable correlations for MgO-water nanofluid. The findings show that thermal conductivity, viscosity, and density of nanofluid increases with increasing solid volume fraction.

Abstract: Hydroxyl-terminated polybutadiene (HTPB) coating is continuously affected by environment/load spectrum during storage, and its macro and micro mechanical properties will deteriorate. Therefore, the cyclic tension test of HTPB coating was carried out with the elongation of HTPB coating was 5%, 10% and 15%, the tensile rate was 50mm/min, 100mm/min and 500mm/min, respectively, and the tensile times was 1000, and the macro and micro mechanical properties of the samples after cyclic tension were tested. The results show that the maximum stress that can be reached by each cyclic tension decreases with the increase of cyclic times, which proves that stress relaxation occurs. After cyclic tension, the tensile strength and cross-linking density of HTPB coating decrease with the increase of elongation and raise with the increase of tensile rate. There is a good linear correlation between cross-linking density and tensile strength.

Abstract: One of the important soil materials for the evaluation of settlement due to consolidation of soil clay is the compression index (Cc). The assessment of its value through laboratory testing is usually time consuming and expensive. Hence to find the most appropriate model prediction, the paper is examined the compression index comparison with soil plasticity material (water content, liquid limit, plasticity index). The analysis is used by multiple regression analysis and some performance indicators such as Coefficient of Determination (R²), Index of Agreement (IA), Prediction Accuracy (PA), Normalized Absolute Error (NAE) and Root Mean Square Error (RMSE). The result identified the proposed model by Skempton’s, Sidharan, Nagaraj’s and Hough’s are suitable for the compression index (Cc) equation model. Another essential point, the research is found error measurement for soil plasticity index properties. Thus, this prediction model is useful to develop a preliminary assessment of the settlement of structures and carry out suitable action for landslides in Teziutlan, Mexico.

Abstract: This study was conducted to analyze the correlation between traits of fruit mulberry from 71 hybrid accessions. The results revealed that the fruit yield (FY) had intermediately positive correlated to branch per trunk (BPT, r = 0.46). Fruit width (FWI) had very highly positive correlated to fruit length (FL, r = 0.77) and fruit weight (FWE, r = 0.86). Fruit length (FL) had highly positive correlated to fruit weight (FWE, r = 0.91) but had slightly negative correlated to bud per branch (BPB, r = -0.28). Fruit weight (FWE) had slightly positive correlated to branch length per trunk (BLPT, r = 0.27) but had slightly negative correlated to bud per branch (BPB, r = -0.29). Finally, branch length per trunk (BLPT) had intermediately negative correlated to bud per branch (BPB, r = -0.39). Additionally, the economic traits which had highly positive direct effect through fruit yield was branch length per trunk (BLPT, path coefficient = 0.428). The correlation and path analysis are suggested for the direct selection of branch length per trunk for fruit mulberry yield improvement. This result showed the relationship among traits and making indirect criteria for selection fruit mulberry in breeding system.

Abstract: This study was conducted to stabilize the correlation parameter for economic traits of local rice (Oryza sativa L.). The results revealed that the number of tiller (NT) was positively correlated with plant height (PH, r = 0.55211), number of panicle (NP, r = 0.48390), panicle length (PL, r = 0.31181), seed length (SL, r = 0.33430), total seed weight (TSW, r = 0.28122), however, the negatively correlated with seed width (SW, r = -0.26725). Plant height (PH) was negatively correlated with seed width (SW, r = -0.42971) and 100 seed weight (HS, r = -0.28991). Number of panicle (NP) was positively correlated with panicle length (PL, r = 0.32888) and total seed weight (TSW = 0.75128). Panicle length (PL) was positively correlated with number of seed (NS, r = 0.38332), seed length (SL, r = 0.53582) and total seed weight (TSW, r = 0.51078). Number of seed (NS) was positively correlated with total seed weight (TS, r = 0.54696). Seed length (SL) was positively correlated with 100 seed weight (HS, r = 0.46799) and total seed weight (TSW, r = 0.33826). Seed width (SW) was positively correlated with 100 seed weight (HS, r = 0.66074). In this experiment, multiple regression formula was Y(TSW) = -51.31 + 0.045(PH) + 2.77(NP) + 0.21(NS) + 8.88(HS) with R² = 0.5644. Our results represent the relationship among traits and making for design a crop model in rice planting system.

Abstract: The present study is performed for investigation of the correlation between UPV value and strength of rubber-concrete. Compressive and splitting tensile strengths of concrete containing waste tire-rubber particles by four different volume contents were investigated using ultrasonic pulse velocity (UPV) test and direct destructive tests. Test results showed that ultrasonic pulse velocity test can be successfully estimated to the strength of rubber-concrete as used in normal concrete.

Abstract: Equilibrium adsorption of quaternary component mixture (phenol, butanol, butan-2-ol and 2-methyl butan-2-ol) onto activated carbon derived from oil-palm empty fruit bunch was studied. Henry isotherm 2-parameter model was used as an improvement to Langmuir and Freundlich 2-parameter isotherm model. The 3-parameter isotherm models applied to the quaternary adsorption system included Redlich Peterson, Sips and Toth. Trial and error method of excel solver was used to evaluate the parameters in the models. Data fitness was based on correlation coefficient (R2) and average percentage error (APE). For the two-parametric isotherm models, Langmuir predicted the adsorption equilibrium well with APE and R2 values of 0.20883 and 0.9868; 0.007669509 and 0.9338; and 3.64355718 and 0.9410 for butanol, butan-2-ol and 2-methyl butan-2-ol respectively. The maximum mono-layer capacity (qm) obtained from Langmuir model for butanol, butan-2-ol and 2-methyl butan-2-ol adsorption were 3558.962mg/g, 2.064233mg/g and 22.6423mg/g respectively. Sip and Toth fitted excellently well among the three- parametric isotherm models. The Sip isotherm model gives APE and R2 values of 0.010536 and 0.9346; and 5.14458 and 0.9250 for phenol and 2-methyl butan-2-ol respectively. The Toth isotherm model gives APE and R2 values of 4.83521 and 0.9866; and 0.02595 and 0.9411 for butanol and butan-2-ol respectively. The isotherm models prove applicable for the quaternary adsorption system.

Abstract: The aim of this study is to model the distribution patterns of the different mechanical properties of a submerged arc welded pipeline steel API X70 and to investigate the relationship between Vickers hardness and other mechanical properties of API X70. In this study, serial mechanical properties of 70 pipes, formed by spiral submerged arc welding of high strength low alloy steel (HSLA) API X70, were measured in base metal and weldments. Four main statistical distributions: Normal, Log-normal, Weibull and smallest extreme value distributions were chosen to test the goodness of fit to the experimental data. As a result, normal and lognormal distributions can equally model the distribution patterns of the whole experimental data of studied mechanical properties except for the hardness and toughness of the base metal that can be approximated by Weibull and smallest extreme value distributions, respectively. Using the current data, a weak but statistically significant correlation is obtained only between the toughness of the fusion zone and the hardness of both the base metal and the heat affected zone. Consequently, the calculated regression models were unable to estimate impact toughness values based on future measures of Vickers hardness components.

Abstract: In this article greencomposites based on gypsum reinforced with date palm fibers (DPF) were fabricated and investigated experimentally in terms of thermal and mechanical properties. This paper deals with two aspects, the first one is a study on the influence of fibers sizes and content on thermal diffusivity and Young’s modulus of date palm fibers (DPF) reinforced gypsum composite. The second one is an experimental correlation investigation between Young’s modulus and thermal properties (thermal conductivity, thermal diffusivity). According to the results of this study, the Young’s modulus and the thermal diffusivity of the greencomposites is mainly influenced by the interfacial adhesion between the matrix and fibers. The experimental correlation between Young’s modulus and thermal properties shows variant results.

Abstract: This paper describes a Monte Carlo simulation of the correlated steel characteristics of yield stress and ultimate strength of steel S235 grade from Northern Moravia region in the Czech Republic. Their joint distribution is described by a correlation index and frequency histograms. The paper step-by-step describes simulation process of the transformation of a correlated Gaussian joint distribution to a general joint distribution, because the yield stress as well as ultimate steel strength random parameters do not follow a Gaussian distribution. Their marginal distribution can be easily described by a suitable parametric distribution or frequency histogram suitable for use with the Simulation-based Reliability Assessment method (SBRA). Describing joint distributions of non-Gaussian processes is overcome by application of fractile correlation.