Nonintrusive data-based learning of a switched control heating system using POD,DMD and ANN

The aim of this work is to derive an accurate model of two-dimensional switched control heating system from data generated by a Finite Element solver. The nonintrusive approach should be able to capture both temperature fields, dynamics and the underlying switching control rule. To achieve this goal, the algorithm proposed in this paper will make use of three main ingredients: proper orthogonal decomposition (POD), dynamic mode decomposition (DMD) and artificial neural networks (ANN). Some numerical results will be presented and compared to the high-fidelity numerical solutions to demonstrate the capability of the method to reproduce the dynamics.     

附加压力与分散系统的稳定性

较详细地讨论了附加压力与分散系统稳定性间的关系,指出分散相附加压力的降低是分散系统趋向稳定的根本原因。以乳状液为例,附加压力降低不仅减少了液滴间相互碰撞的概率,而且更重要的是,它与液滴表面形成牢固的保护膜密切相关。只有当液滴的附加压力趋近0时,分散系统才达到热力学上稳定的状态,此时乳状液已变成了微乳状液。上述讨论也基本适用于固/液分散系统。     

过渡金属Co2+离子掺杂ZnS硫化物纳米晶制备与中红外发光特性研究

利用不含有机相的简单水热法制备了Co^2+∶ZnS纳米晶,纳米晶具有立方闪锌矿结构,平均晶粒尺寸约为8.3 nm,在808 nm激光泵浦下具有2~5μm波段的中红外荧光发射,中心波长位于3400 nm和4700 nm,分别对应Co^2+离子的4T2(F)→4 A 1(F)和4T1(F)→4T2(F)的能级跃迁.进一步将制备的纳米晶在还原气氛下进行800℃热处理,获得立方闪锌矿和纤锌矿混合晶型的纳米晶,平均晶粒尺寸增大到22.5 nm左右,热处理后的纳米晶表面羟基含量更低,中红外荧光发射强度显著提高.该Co^2+∶ZnS纳米晶的制备方法简单、在制备过程中不引入有机相等荧光淬灭中心,同时证明通过后热处理过程可以进一步减少表面缺陷及羟基含量,使荧光强度得到大幅提升.     

无溶剂热处理固相转化法简易制备沸石咪唑酯骨架材料

设计开发了一种无需溶剂，通过热处理固相转化制备沸石咪唑酯骨架材料（ZIFs）的简易方法.该方法无需溶剂及其它预处理，只需将金属源与有机配体固相混合后于低温（200℃）热处理即可实现多孔晶体材料的制备.所合成材料H-ZIF-67为具有方纳石拓扑结构的纳米晶体，与传统方式合成的ZIFs材料一致.粉末X射线衍射（PXRD）分析结果表明产物的晶体结构与标准ZIFs谱图一致.通过扫描电子显微镜（SEM）、透射电子显微镜（TEM）、N₂吸附-脱附分析、热重分析（TGA）和傅里叶变换红外光谱（FTIR）等手段对合成的材料进行了表征，发现H-ZIF-67材料具有与ZIFs材料类似的特性.该方法经济、高效，摒弃了传统方法合成ZIFs材料周期长、处理过程复杂的弊端，为ZIFs材料的量产提供了新思路.     

Soret and Dufour aspect of viscoelastic fluid due to moving cylinder with viscous dissipation and convective boundary conditions

Owing to contribution of thermo-diffusion phenomenon in various engineering and industrial frame works, scientists have presented some exclusive investigations on this topic. In current research, the thermos-diffusion prospective of second grade material accounted by a moving cylinder have been predicted. The applications of Soret and Dufour effects based on the thermos-diffusion phenomenon is evaluated. The magnetic force and viscous dissipation effects are presented for the current flow model. Additionally, the improvement in thermal transport of viscoelastic fluid is suggested with radiative phenomenon. The convective boundary constraints are used to report the thermos-diffusion phenomenon. The system based on dimensionless form is obtained with interaction of new variables. The shooting technique is used for numerical observations by using MATLAB software. The physical impact of phenomenon in view of parameters is graphically attributed. It has been noted that increasing velocity profile is results due to curvature parameter and viscoelastic parameter. The enhancement in thermal profile is noted due to Dufour number and Eckert number.     

Synthesis,characterization and electrochemical investigation on Nickel Manganese Oxide - Polybutylene Sebacate composite electrode of biodegradable nature for micro capacitor applications

Synthesis, characterization, surface morphology and electrochemical properties of non-stochiometric Nickel–Manganese oxide nanoparticles were carried out by urea assisted sol gel method. The Ni_1-xMn_xO (0.15≤ X ≤ 0.50) nanoparticle synthesized was found to be cubic and the existence of Mn₃O₄ and MnO₂ phases were established and confirmed by X-ray Diffraction (XRD) studies. Thermo Gravimetric-Differential Thermal Analysis (TG-DTA) studies provided the calcination temperature of the xerogel at 600 °C, wherein the lattice strain and the size of the nanoparticles were determined through Williamson Hall (WH) Plot. The surface morphology characteristics of these nanoclusters were authenticated by Scanning Electron Microscope (SEM) techniques. Further, electroanalytical techniques were employed as a tool in establishing the nanocomposite as an intriguing material to act as a capacitor at enhanced efficiency compared to that of conventional capacitors. The electrochemical competence of the electrode was established through cyclic voltammogram, (CV) and Electrochemical Impedance Spectral (EIS) studies. The values of capacitance for Ni_1-xMn_xO, (0.15≤ X ≤ 0.5) nanoparticles varied from 7000 to 8000 mFg^?1, measured at 20 mVs^?1scan rate in 1.0 M Na₂SO₄and the temperature dependent conductance property for Ni_0.85Mn_0.15O electrode verified the Arrhenius Equation. The synthesis of a biodegradable polymer, Poly Butylene Sebacate (PBS) employed as conducting polymer for ultra capacitor applications is comparatively superior and definitely provides an edge over other capacitors in existence which is predominanantly attributed to its biodegradability nature. Further, the specific capacitance of PBS- Ni_0.85Mn_0.15O composite electrode was found to be 5180 mFg^?1 which clearly illustrates that these composites are potential candidates of the type biodegradable supercapacitors that are evolving transient sources of power in the future and the biodegradability of the polymer-metal oxide composite electrode fetches more significance in terms of disposal of electronic and electrical wares.     

A lubricated stagnation point flow of nanofluid with heat and mass transfer phenomenon: Significance to hydraulic systems

The improved thermal association of heat transfer is considerably observed due to interaction of nanoparticles in recent days. The lubrication phenomenon with heat and mass transfer effects plays a key role in the hydraulic systems. In current research, the thermal impact of nanofluid over a lubricated stretching surfaces near a stagnation point analytical has been studied. A thin layer of lubricating fluid with a variable thickness provides lubrication. The inspection of thermophoresis and Brownian motion phenomenon is illustrated via Boungrino model. The analytical finding of refurbished boundary layer ordinary differential equations is obtained by a reliable and proficient technique namely variational iteration method (VIM). The Lagrange Multiplier is a potent tool in proposed technique to reduce the computational work. In addition, a numerical comparison is presented to show the effectiveness of this study. The range of flow parameters is based on theoretical flow assumptions. Physical inspection of involved parameters on velocities, temperatures, concentrations, and other quantities of interest when lubrication is presented. The current results present applications in polymer process, manufacturing systems, heat transfer and hydraulic systems.     

Synthesis of a novel naphthyl-based self-catalyzed phthalonitrile polymer

A novel naphthyl-based self-catalyzed phthalonitrile monomer was prepared via nucleophilic displacement reaction. The structure was characterized by Fourier infrared spectrum (FT-IR) and nuclear magnetic resonance (1H NMR). The polymerization mechanism was explored. Thermal properties were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), which demonstrated self-promoted behavior and excellent heat resistance.