Electro-mechanical behavior and direct piezoelectricity of cellulose electro-active paper

This study focuses on investigating the piezoelectric effects of cellulose-based electro-active paper (EAPap) using quasi-static direct piezoelectricity. Mechanical properties were investigated first and then electro-mechanical behavior was studied by applying electric field during the pulling test. In-plane piezoelectric charge constant (d₃₁) of EAPap was quantified by the quasi-static relation between induced charge and applied stress. Strong shear electro-mechanical coupling was observed and 45° sample provided the largest in-plane piezoelectric charge constant. The measured piezoelectric charge constant was in the range of 8–28.2 pC/N, which are similar to those of piezo polymer. Cellulose EAPap provides promising potential as biodegradable and cheap piezoelectric polymer material.     

Electrical stimuli-induced deformation and material properties of electro-active polymer Nafion117

The material properties of Nafion117 in water are investigated through experiments and finite-element analysis (FEA) to derive parameters for use in future FEA studies of the coupling diffusion of water and structural mechanics of EAPs in aqueous solution. The deformation behavior of Nafion117 in distilled water under the application of an electric potential is examined experimentally to clarify the relationships between applied voltage, current and deformation. The water content in wet Nafion117 and the coefficient of linear expansion due to water absorption are found experimentally to be 0.434 [(mm³)_aq/(mm³)_dp] and 0.243 [(mm³)_dp/(mm³)_aq]. Through experiments and corresponding FEA simulations on the free vibration of a Nafion117 cantilever in distilled water and a gold-plated cantilever, the Young's modulus and β coefficient of Rayleigh damping are found to be 7.0 MPa and 0.02 s, respectively.     

Topology optimization of conductive heat transfer problems using parametric L-systems

Generative encodings have the potential of improving the performance of evolutionary algorithms. In this work we apply parametric L-systems, which can be described as developmental recipes, to evolutionary topology optimization of widely studied two-dimensional steady-state heat conduction problems. We translate L-systems into geometries using the turtle interpretation, and evaluate their objective functions, i.e. average and maximum temperatures, using the Finite Volume Method (FVM). The method requires two orders of magnitude fewer function evaluations, and yields better results in 10 out of 12 tested optimization problems (the result is statistically significant), than a reference method using direct encoding. Further, our results indicate that the method yields designs with lower average temperatures than the widely used and well established SIMP (Solid Isotropic Material with Penalization) method in optimization problems where the product of volume fraction and the ratio of high and low conductive material is less or equal to 1. Finally, we demonstrate the ability of the methodology to tackle multi-objective optimization problems with relevant temperature and manufacturing related objectives.     

Development of Adaptive Modular Active Leg (AMAL) using bipedal robotics technology

The objective of the work presented here is to develop a low cost active above knee prosthetic device exploiting bipedal robotics technology which will work utilizing the available biological motor control circuit properly integrated with a Central Pattern Generator (CPG) based control scheme. The approach is completely different from the existing Active Prosthetic devices, designed primarily as standalone systems utilizing multiple sensors and embedded rigid control schemes. In this research, first we designed a fuzzy logic based methodology for offering suitable gait pattern for an amputee, followed by formulating a suitable algorithm for designing a CPG, based on Rayleigh’s oscillator. An indigenous probe, Humanoid Gait Oscillator Detector (HGOD) has been designed for capturing gait patterns from various individuals of different height, weight and age. These data are used to design a Fuzzy inference system which generates most suitable gait pattern for an amputee. The output of the Fuzzy inference system is used for designing a CPG best suitable for the amputee. We then developed a CPG based control scheme for calculating the damping profile in real time for maneuvering a prosthetic device called AMAL (Adaptive Modular Active Leg).Also a number of simulation results are presented which show the stable behavior of knee and hip angles and determine the stable limit cycles of the network.     

A selective conductive polymer-based sensor for volatile halogenated organic compounds (VHOC)

A novel poly(p-xylylene), PPX, derivative bearing alkoxyphenyl side groups was electrochemically synthesized in 87% yield. The polymer, poly(4′-hexyloxy-2,5-biphenyleneethylene) (PHBPE), presented a fraction (92%) soluble in common organic solvents. It showed to be thermally resistant up to 185 °C. UV–vis analysis revealed an E_gap of 3.5 eV. Gas sensors made from thin films of 10-camphorsulfonic acid-doped PHBPE deposited on interdigitated electrodes exhibited significant changes in electrical conductance upon exposure to five VHOCs: 1,2-dichloroethane, bromochloromethane, trichloromethane, dichloromethane and tetrachloromethane. The conductance decreased after exposure to tetrachloromethane and increased after exposure to all the other VHOCs. Three-dimensional plots of relative response versus time of half response versus time of half recovery showed good discrimination between the five VHOCs tested.     

Creep response calculation of rubber-like polymers using ADINA

An application of the ADINA program to the creep response of rubber-like polymers under static loading conditions is presented. Rubber is characterized as a nearly-incompressible material through the entire deformation, where the inelastic strain is comparable with the elastic strain. The analysis is comprised of the material modeling using superposition of two types of elements occupying the same space: nearly incompressible (u/p) elements dictating elastic-dilatational response without shear stiffness, and elastic and creep elements (with the updated Lagrangian Hencky formulation and the effective-stress-function algorithm) representing deviatoric response. The idea is demonstrated and verified in typical examples of aging problems.     

Investigation of the impact on the radio frequency (RF) behaviour of electrically conductive adhesives (ECAs) used in wafer-level packaging (WLP) of RF-MEMS

Microsystem Technologies - In this work, an anisotropic conductive adhesive (ACA), belonging to the family of electrically conductive adhesives (ECAs), exploited for the wafer-level bonding phase...     

Sensoring hydrogen gas concentration using electrolyte made of proton conductive manganese dioxide

Hydrogen gas promises to be a major clean fuel in the near future. Thus, sensors that can measure the concentrations of hydrogen gas over a wide dynamic range (e.g., 1-99.9%) are in demand for the production, storage, and utilization of hydrogen gas. However, it is difficult to directly measure hydrogen gas concentrations greater than 10% using conventional sensor [1], [2], [3], [4], [5], [6], [7], [8], [9], [10] and [11]. We report a simple sensor using an electrolyte made of proton conductive manganese dioxide that enables in situ measurements of hydrogen gas concentration over a wide range of 0.1-99.9% at room temperature.     

Development of stacked conductive templates for electroforming of multi-level metallic micro components

Economic mass manufacturing of metallic micro components requires effective methods to produce the adequate partial conductive templates. Especially in case of stacked or multi-level micro components a considerable increase in economic efficiency could be achieved if originally made templates, e.g. by LIGA, would be replaced by much cheaper replicated ones. For this purpose a modified injection molding process to produce stacked and partially conductive polymeric templates had been developed. As suitable demonstrator a combination of a gear wheel with an adequate shaft was chosen. Electroforming trials using a standard nickel sulfamate electrolyte were carried out. Finally, the stepwise electroplating procedure filling the shaft cavity first subsequently the gear wheel cavity could be realized. The lateral dimensions were measured and the surfaces of the metal components were characterized by SEM.

     

Investigating the role of metallic fillers in particulate reinforced flexible mould material composites using evolutionary algorithms

To reduce the cooling time in soft tooling (ST) process, high thermal conductive fillers (such as metallic filler) are included in flexible mould material. But addition of metallic fillers affects various properties of ST process and the influences may vary according to the types of materials used. Therefore, in order to investigate the role of various metallic fillers in particulate reinforced flexible mould material composites, multi-objective optimizations of maximizing equivalent thermal conductivity and minimizing effective modulus of elasticity of composite mould materials are conducted using evolutionary algorithms (EAs). Here we have adopted two EA-based algorithms namely NSGAII and SPEA2 in order to solve the present problem independently. Comparative study of the results reveals that NSGAII performs better over SPEA2 for investigating the role of metallic fillers in particulate reinforced flexible mould material composites. A recently proposed innovization procedure is also used to unveil salient properties associated with the obtained trade-off solutions. These solutions are analyzed to study the role of various parameters influencing the equivalent thermal conductivity and modulus of elasticity of the composite mould material. Based on the findings through investigations, the optimal selection of materials is suggested including the cost implication factor.     

Novel e-nose for the discrimination of volatile organic biomarkers with an array of carbon nanotubes (CNT) conductive polymer nanocomposites (CPC) sensors

We report the original design of a new type of electronic nose (e-nose) consisting of only five sensors made of hierarchically structured conductive polymer nanocomposites (CPC). Each sensor benefits from both the exceptional electrical properties of carbon nanotubes (CNT) used to build the conductive architecture and the spray layer by layer (sLbL) assembly technique, which provides the transducers with a highly specific 3D surface structure. Excellent sensitivity and selectivity were obtained by optimizing the amount of CNT with five different polymer matrices: poly(caprolactone) (PCL), poly(lactic acid) (PLA), poly(carbonate) (PC), poly(methyl methacrylate) (PMMA) and a biobased polyester (BPR). The ability of the resulting e-nose to detect nine organic solvent vapours (isopropanol, tetrahydrofuran, dichloromethane, n-heptane, cyclohexane, methanol, ethanol, water and toluene), as well as biomarkers for lung cancer detection in breath analysis, has been demonstrated. Principal component analysis (PCA) proved to be an excellent pattern recognition tool to separate vapour clusters.     

Development of an integrated game theory-optimization subground stratification model using cone penetration test (CPT) measurements

The continuous cone penetration test (CPT) measurements provide an advantageous liable rapid tool for stratification and soil behavior classification that can be employed in the sustainable design of the infrastructures. However, the CPT measurements are often interpreted by geotechnical experts because of the involved complexities and uncertainties. In this study, a novel stratification and soil type behavior (SBT) classification model is developed to identify the transition and thicker layers by integrating the geotechnical knowledge with the three submodels of (a) locally estimated scatterplot smoothing (LOESS), (b) a game theory model known as Nash–Harsanyi (N–H) bargaining, and (c) grey wolf optimizer (GWO). The LOESS and integrated N–H bargaining-GWO models are, respectively, used to approximate the outliers in CPT measurements and identify the SBT and layer changes. Attractively, in the proposed model, the engineer has the opportunity to judge on the precision of the stratification profile regarding their own preferences in a project. Solving simple algebraic equations, high speed, identifying thick and the interlayer transition layers, and small required training data are the other advantages of the developed model. Finally, the applicability of the proposed model has been assessed in an example. The compared estimated and two other models’ stratification profiles highlighted the potential of the proposed model to identify thin transition layers.

     

Investigation on fracture and conductivity of flex-on-film flexible bonding using anisotropic conductive film considering repeated bending

Microsystem Technologies - This study conducts an experimental investigation into the bending behavior and electrical resistance properties of Flex (PI with Cu)-On-Film (ITO–coated PET)...     

传导矛盾问题的成因及解决方法

由于目前还没有对传导矛盾问题的成因进行过深入剖析,所以无法给出有效的解决方案.为解决此问题,定义了传导相关度,并通过其找到传导矛盾问题的根本成因,然后将其转化为TRIZ理论中的技术矛盾,再利用矛盾矩阵中的创新理论找到传导矛盾问题的解决方案.应用实例表明了该方法的有效性,为复杂矛盾问题系统中传导矛盾问题的分析和解决提供了参考依据.     

序列模式挖掘研究与发展

序列模式挖掘是数据挖掘的一个重要研究课题,它在很多领域中都有着广泛的应用.首先讨论了序列模式挖掘的相关背景,然后对序列模式挖掘进行分类,并在此基础上对每一类序列模式挖掘算法的特点进行了介绍和比较;最后,对序列模式挖掘未来的研究重点进行展望,以便研究者对序列模式挖掘做进一步的研究.     

计算机管理教学(CMI)的设计和进展

计算机管理教学是计算机教学的重要组成部分。该文结合国际上最新CMI研究进展介绍了CMI系统的发展、特点、功能以及目前世界上流行的CMI标准。此外文章还介绍了CMI系统的功能设计情况。     

虚拟现实（VR）技术与发展研究综述

在人工智能与5G技术的背景下,笔者通过文献调研法和内容分析法,对VR相关文献的发布数量和主题分布进行了研究,分析了近年VR技术的关注程度、发展趋势与热点分布。具体来说,笔者调研并总结了VR技术的历史、发展以及最新进展情况,列举了VR技术与5G技术融合在产业应用领域的最新成果,对VR技术与空间定位技术、语义与情感识别技术、信息融合技术结合在智慧城市、智慧工业、数字孪生等领域的发展前景进行了展望与探讨。     

虚拟设备驱动程序VxD的研究与开发

分析了Windows9x的VxD技术的实现机制与原理，讨论了基于VToolsD的虚拟设备驱动程序VxD开发方法，并给出了一个编程实例。     

计算机电信集成技术及其发展

本文介绍了计算机电信集成技术及其进展，特别详尽分析了它的三种实现形式：点对点形式、交换机－计算机形式、客户／服务器形式。