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Modeling Water Adsorption and Retention of Building Materials From Pore Size Distribution
No full textWater adsorption and capillarity are key phenomena involved during heat and moisture transfer in porous building materials. They account for interaction between solid matrix, liquid water and moist air. They are considered through Water Vapor Adsorption Isotherm (WVAI) and Retention Curve (RC) functions which are constitutive laws characterizing water activity within a porous medium. The objective of this paper is to present a water vapor adsorption and retention models built from multimodal Pore Size Distribution Function (PSDF) and to see how its parameters modify moisture storage for hygroscopic and near saturation ranges. The microstructure of the porous medium is represented statistically by a bundle of tortuous parallel pores through its PSDF. Firstly, the influence of contact angle and temperature on storage properties were investigated. Secondly, a parametric study was performed to see the influence of the PSDF shape on storage properties. Three cases were studied considering the number of modalities, the weight of each modality and the dispersion around mean radius. Finally, as a validation, the proposed model for WVAI were compared to existing model from literature showing a good agreement. This study showed that the proposed models are capable to reproduce various shapes of storage functions. It also highlighted the link between microstructure and adsorption-retention phenomena
ZnSe Nanoparticles Reinforced Biopolymeric Soy Protein Isolate Film
No full textZnSe nanoparticles have been synthesized by microwave assisted method by using zinc chloride, selenium powder and ethylene diamine. The synthesized nanoparticles have been characterized structurally by FT-IR and XRD as well as morphological characterization was done by scanning electron microscope (SEM). The crystallite size after synthesis was obtained around 30 nm for pure ZnSe nanocrystallites. However, from SEM micrograph, agglomerated ZnSe nanoparticles of irregular shapes were observed. The as-synthesized ZnSe nanoparticles at different contents (1 to 5% w/w w.r.t SPI) were incorporated into soy protein isolate (SPI) to produce reinforced SPI films by solution casting method. The ZnSe nanoparticles incorporated SPI suspensions were subjected to molecular mass and specific conductivity studies. Neat and ZnSe nanoparticles incorporated SPI films were structurally and mechanically characterized by FT-IR and tensile properties, respectively. Transmittance and water uptake studies were also carried out for ZnSe nanoparticles incorporated SPI films. The tensile strength and modulus increased from 5.80 MPa to 10.06 MPa and 18.84 MPa to 94.70 MPa with the increase in the contents of ZnSe nanoparticles from 0 to 5%. Moreover, the results also revealed a good antibacterial effect in ZnSe nanoparticles incorporated SPI film. The main application of nanoparticles incorporated SPI film will be in the area of biodegradable packaging
Effect of Soluble Components From Plant Aggregates on the Setting of the Lime-Based Binder
No full textPlant aggregate-based building materials are a viable solution for reducing greenhouse gas emissions and providing good thermal and acoustic performances. In this study, the investigated lightweight mortars require a hydraulic reaction. Laboratory and on-site empirical observations about plant aggregate-based materials indicate a delay in setting time and a decrease in the mechanical performances of concretes based on plant aggregates. The natural origin of plant-aggregates causes a lot of variability in their properties. Related studies have shown that the incompatibility between plant aggregates and cement is mainly caused by the dissolved and decomposed components of plant aggregates in alkaline environments. Currently, no research on the specific impact of each component on the setting time of lime-based binder exists. In this work, the impact of some soluble compounds (e.g., sucrose, glucose, fructose, pectin) on the setting reaction of the lime matrix was studied using Vicat test, thermogravimetric analysis (TGA) and FT-IR spectroscopy. Experimental results showed that carbohydrates such as glucose and sucrose not only affect the setting time but also have a long-term impact on the carbonation of lime. The measure of the setting time by Vicat test appears as a possible indicator to predict the compatibility between the matrix and plant aggregates
Monitoring of Real-Time Complex Deformed Shapes of Thin-Walled Channel Beam Structures Subject to the Coupling Between Bi-Axial Bending and Warping Torsion
No full textStructural health monitoring (SHM) is a research focus involving a large category of techniques performing in-situ identification of structural damage, stress, external loads, vibration signatures, etc. Among various SHM techniques, those able to monitoring structural deformed shapes are considered as an important category. A novel method of deformed shape reconstruction for thin-walled beam structures was recently proposed by Xu et al. [1], which is capable of decoupling complex beam deformations subject to the combination of different loading cases, including tension/compression, bending and warping torsion, and also able to reconstruct the full-field displacement distributions. However, this method was demonstrated only under a relatively simple loading coupling cases, involving uni-axial bending and warping torsion. The effectiveness of the method under more complex loading cases needs to be thoroughly investigated. In this study, more complex deformations under the coupling between bi-axial bending and warping torsion was decoupled using the method. The set of equations for deformation decoupling was established, and the reconstruction algorithm for bending and torsion deformation were utilized. The effectiveness and accuracy of the method was examined using a thin-walled channel beam, relying on analysis results of finite element analysis (FEA). In the analysis, the influence of the positions of the measurement of surface strain distributions on the reconstruction accuracy was discussed. Moreover, different levels of measurement noise were added to the axial strain values based on numerical method, and the noise resistance ability of the deformation reconstruction method was investigated systematically. According to the FEA results, the effectiveness and precision of the method in complex deformation decoupling and reconstruction were demonstrated. Moreover, the immunity of the method to measurement noise was proven to be considerably strong
A Fractional Order HIV Internal Viral Dynamics Model
No full textIn this paper, a fractional order model is established to describe HIV internal viral dynamics involving HAART effect. First, the model is proved to possess non-negative solutions as desired in any population dynamics. Then, a detailed analysis is carried out to study the stability of equilibrium points. Numerical simulations are presented to illustrate the stability analysis
Mixed Convection of Bingham Fluid in a Two Sided Lid-Driven Cavity Heated From Below
Get PDFThis study aims to analyze mixed convection in a square cavity with two moving vertical walls by finite volume method. The cavity filled with Non-Newtonian fluid of Bingham model is heated from below and cooled by the other walls. This study has been conducted for certain parameters of Reynolds number (Re=1-100), Richardson number (Ri=1-20), Prandtl number (Pr=1-500), and Bingham number has been studied from 0 to 10. The results indicate that the increase in yield stress drops the heat transfer and the flow become flatter, while increasing Reynolds number augments it. The convective transport is dominant when increasing Richardson number which leads to enhance heat transfer in the cavity for both Newtonian and Non-Newtonian fluid. A correlation of Nusselt number is given in function of different parameters
Some Topological Indices Computing Results If Archimedean Lattices L(4,6,12)
Get PDFThe introduction of graph-theoretical structure descriptors represents an important step forward in the research of predictive models in chemistry and falls within the lines of the increasing use of mathematical and computational methods in contemporary chemistry. The basis for these models is the study of the quantitative structure-property and structure-activity relationship. In this paper, we investigate Great rhom-bitrihexagonal which is a kind of dodecagon honeycomb net-work covered by quadrangle and hexagon. Many topological indexes of Great rhom-bitrihexagonal have being investigated, such as sum-connectivity index, atom-bond connectivity index, geometric-arithmetic index, fifth, harmonic index, Randić connectivity index, first Zagreb index, second Zagreb index and the corresponding Zagreb polynomials, modified Zagreb index, fourth atom-bond connectivity index, augmented Zagreb index, hyper-Zagreb index, Sankruti index, forgotten topological index, first multiple Zagreb index, second multiple Zagreb index, as well as derived geometric-arithmetic index, Narumi-Katayama index and modified Narumi-Katayama index
Spatial Quantitative Analysis of Garlic Price Data Based on ArcGIS Technology
Get PDFIn order to solve the hidden regional relationship among garlic prices, this paper carries out spatial quantitative analysis of garlic price data based on ArcGIS technology. The specific analysis process is to collect prices of garlic market from 2015 to 2017 in different regions of Shandong Province, using the Moran's Index to obtain monthly Moran indicators are positive, so as to analyze the overall positive relationship between garlic prices; then using the geostatistical analysis tool in ArcGIS to draw a spatial distribution Grid diagram, it was found that the price of garlic has a significant geographical agglomeration phenomenon and showed a multi-center distribution trend. The results showed that the agglomeration centers are Jining, Dongying, Qingdao, and Yantai. At the end of the article, according to the research results, constructive suggestions were made for the regulation of garlic price. Using Moran’s Index and geostatistical analysis tools to analyze the data of garlic price, which made up for the lack of position correlation in the traditional analysis methods and more intuitively and effectively reflected the trend of garlic price from low to high from west to east in Shandong Province and showed a pattern of circular distribution
A Co-Verification Interface Design for High-Assurance CPS
Get PDFCyber-Physical Systems (CPS) tightly integrate cyber and physical components and transcend traditional control systems and embedded system. Such systems are often mission-critical; therefore, they must be high-assurance. High-assurance CPS require co-verification which takes a comprehensive view of the whole system to verify the correctness of a cyber and physical components together. Lack of strict multiple semantic definition for interaction between the two domains has been considered as an obstacle to the CPS co-verification. A Cyber/Physical interface model for hierarchical a verification of CPS is proposed. First, we studied the interaction mechanism between computation and physical processes. We further classify the interaction mechanism into two levels: logic interaction level and physical interaction level. We define different types of interface model according to combinatorial relationships of the A/D (Analog to Digital) and D/A (Digital to Analog) conversion periodical instants. This interface model has formal semantics, and is efficient for simulation and formal verification. The experiment results show that our approach has major potential in verifying system level properties of complex CPS, therefore improving the high-assurance of CPS
The Application of BP Neural Networks to Analysis the National Vulnerability
Get PDFClimate change is the main factor affecting the country’s vulnerability, meanwhile, it is also a complicated and nonlinear dynamic system. In order to solve this complex problem, this paper first uses the analytic hierarchy process (AHP) and natural breakpoint method (NBM) to implement an AHP-NBM comprehensive evaluation model to assess the national vulnerability. By using ArcGIS, national vulnerability scores are classified and the country’s vulnerability is divided into three levels: fragile, vulnerable, and stable. Then, a BP neural network prediction model which is based on multivariate linear regression is used to predict the critical point of vulnerability. The function of the critical point of vulnerability and time is established through multiple linear regression analysis to obtain the regression equation. And the proportion of each factor in the equation is established by using the partial least-squares regression to select the main factors affecting the country’s vulnerability, and using the neural network algorithm to perform the fitting. Lastly, the BP neural network prediction model is optimized by genetic algorithm to get the chaotic time series BP neural network prediction model. In order to verify the practicability of the model, Cambodia is selected to be an example to analyze the critical point of the national vulnerability index