组合锥形液体贮罐的简化设计方法

组合圆锥-圆柱形壳形式的钢贮罐是一种常见的用于储存液体的压力罐。大部分此类压力罐的破坏都由于钢壳的失稳而引起。引起这些破坏的主要原因是没有适当的设计方法来对这类结构进行设计。在本次研究中,提出了简化的设计方法,以保证静水加载的组合钢罐在发生屈曲时的安全。应用非线性有限元模型进行数值模拟,对大变形和几何缺陷对钢罐稳定性的破坏作用进行分析。采用有限元计算结果与非线性回归分析建立函数,将壳的总应力与膜应力关联起来。采用算例说明了所提议设计方法的应用。     

Synthesis and characterization of chitosan-coated magnetite nanoparticles using a modified wet method for drug delivery applications

Abstract

Immobilizing various chemical functionalities on the surfaces of magnetite nanoparticles extends these applications without affecting the overall magnetic properties of the coated nanoparticles. In this study, magnetite nanoparticles have been prepared in the presence of chitosan using a simple modified wet method. Composition, morphology and magnetic properties of the chitosan-coated nanoparticles were investigated. Results showed the formation of coating with various thicknesses on the surfaces of the superparamagnetic nanoparticles. This in turn reduced the magnetization of the nanoparticles to some extent. The least particle size obtained in the presence of chitosan was 10?nm.     

Support vector regression-based model for prediction of behavior stone column parameters in soft clay under highway embankment

In order to have a proper design and analysis for the column of stone in the soft clay soil, it is essential to develop an accurate prediction model for the settlement behavior of the stone column. In the current research, to predict the behavior in the settlement of stone column a support vector machine (SVM) method is developed and examined. In addition, the proposed model has been compared with the existing reference settlement prediction model that using the monitored field data. As SVM mathematical procedure has resilient and robust generalization aptitude and ensures searching for global minima for particular training data as well. Therefore, the potential that support vector regression might perform efficiently to predict the ground soft clay settlement is relatively valuable. As a result, in this study, comparison of two different developed types of SVM method is carried out. Generally, significant reduction in the relative error (RE%) and root mean square error has been achieved. Utilizing nu-SVM-type model through tenfold cross-validation procedure could achieve outstanding performance accuracy level with RE% less than 2% and CR = 0.9987. The study demonstrates high potential for applying SVM in detecting the settlement behavior of SC prediction and ascertains that SVM could be effectively used for settlement stone columns analysis.

     

Early detection of Alzheimer’s disease based on the state-of-the-art deep learning approach: a comprehensive survey

Multimedia Tools and Applications - Alzheimer’s disease (AD) is a form of brain disorder that causes functions’ loss in a person’s daily activity. Due to the tremendous progress...     

SOLUBILITY OF CARBON DIOXIDE IN AQUEOUS AND ANHYDROUS MIXTURES OF METHYLDIETHANOLAMINE AND TRIETHYLENE GLYCOL MONOMETHYL ETHER

Mixed solvents are a combination of chemical and physical solvents and are used for the removal of acid gases from gas streams. The solubility of CO₂ in a mixed nonaqueous solution of methyldiethanolamine (MDEA) (50 wt.%) and triethylene glycol monomethj'l ether (TEGMME) (50 wt.%) has been measured at 40°C. The data are compared with solubility data of CO₂ in pure TEGMME. The solubility of CO₂ has been measured at 40°C and 100°C in an aqueous mixed solvent consisting of MDEA (40 wt.%) and TEGMME (40 wt. %) and water (20 wt.%) at partial pressures of CO₂ up to 12 MPa. The solubility results were compared with the solubility in the nonaqueous mixed solvent and previously reported data of aqueous MDEA. The solubility model of Deshmukh and Mather was used to correlate the data.     

Hydrodynamic particle volume and fluidized bed expansion

Particulate fluidized bed expansion may be described by the Richardson-Zaki equation,\documentclass[article]\pagestyle[empty]\begin[document]$ \frac[u][[u_i ]] = e^n $\end[document] The values of n for very fine and/or aggregated particles and for particles of irregular shape are often found to be larger than those for comparable spherical particles. Previous work on aggregated systems by one of the authors showed that a modified Richardson-Zaki equation, \documentclass[article]\pagestyle[empty]\begin[document]$ \frac[u][[u_i ]] = \left( [1 - KC] \right)^n $\end[document] (where C = 1-ε), provided a more consistent correlation of the data. The parameter K accounted for the effective hydrodynamic volume of the particles during fluidization and the application of this concept to non-spherical particles was the subject of the present study. While K for spherical particles was essentially equal to unity, values from 1.17 to 1.43 were found for equidimensional but irregular particles with considerably higher values for flat particles. An equation relating K to particle shape is offered which, when combined with the Richardson-Zaki relationships, provides a more accurate prediction of the expansion behaviour of non-spherical particles.     

Solubilities of Carbon Dioxide in Polyethylene Glycol Ethers

New extensive data are reported for the solubility of carbon dioxide in fourteen physical solvents, and compared to two other solvents widely used in industry (selexol® and sulfolane). The solubility data are expressed by Henry's law constants and have been measured at 25 °C, 40 °C and 60 °C, using an Autoclave cell. The study concludes that polyethylene glycol dimethyl ethers, and mixtures of these solvents are the best solvents for CO₂ removal.     

Structural and Optical Characterization of Chemically Deposited PbS Thin Films

PbS thin films were deposited on glass substrates by a chemical bath deposition method. The effect of varying the film thickness on the structural and optical properties has been investigated. XRD analysis reveals the crystallinity of the deposited PbS films with (200) preferred crystal orientation. Increasing the film thickness enhances the crystallinity of the films as well as decreases the strain and dislocation density. The surface morphology features were dramatically changed from small spherical grains to bead-like shape. The absence of impurities in the deposited films was confirmed by energy dispersive x-ray spectrometry (EDX) measurements. The optical constants of the deposited films were calculated and a small decrease in the band gap energy was observed with increasing the film thickness.     

Effect of Asynchronous Earthquake Motion on Complex Bridges. I: Methodology and Input Motion

Based on observed damage patterns from previous earthquakes and a rich history of analytical studies, asynchronous input motion has been identified as a major source of unfavorable response for long-span structures, such as bridges. This study is aimed at quantifying the effect of geometric incoherence and wave arrival delay on complex straight and curved bridges using state-of-the-art methodologies and tools. Using fully parametrized computer codes combining expert geotechnical and earthquake structural engineering knowledge, suites of asynchronous accelerograms are produced for use in inelastic dynamic analysis of the bridge model. Two multi-degree-of-freedom analytical models are analyzed using 2,000 unique synthetic accelerograms with results showing significant response amplification due to asynchronous input motion, demonstrating the importance of considering asynchronous seismic input in complex, irregular bridge design. The paper, Part 1 of a two-paper investigation, presents the development of the input motion sets and the modeling and analysis approach employed, concluding with sample results. Detailed results and implications on seismic assessment are presented in the companion paper: Effect of Asynchronous Motion on Complex Bridges. Part II: Results and Implications on Assessment.     

CFD modelling of flow and mixing characteristics for multiple rows jets injected radially into a non-reacting crossflow

CFD parametric study was done of flow and mixing characteristics of coolant radial jets injected outwardly from a centerline multiple rows diffuser into a heated non-reacting crossflow in a cylindrical chamber in three-dimensional model using ANSYS-FLUENT 14.5. The effects of jet-mixing ratio, nozzles diameter, diffuser diameter, number of nozzles rows number of nozzles per row on the penetration depth and mixing quality through chamber cross section were parametrically studied. The simulation results were validated with the available experimental data and good agreement was obtained. The results showed that the nozzle diameter, the diffuser diameter and the jet-mixing ratio have remarkable effects on the penetration depth and the mixing quality compared to the effects of number of nozzles per row and the number of nozzle rows. The penetration depth at downstream, the jet diffuser exit and the mixing quality at centerline of chamber exit are increased ?46% & ?49%, respectively, with increasing the jet-mixing ratio from 0.1 to 0.5. Dimensionless correlations in terms of the studied parameters for predicting the penetration depth, mixing quality and maximum temperature difference were developed and presented.