Energy Efficient Target Tracking with Collision Avoidance in WSNs

Wireless sensor network (WSN) is one of the most evolving technologies. WSN involves collecting, processing, transferring and storing information about objects with the help of sensor nodes. Tracking and detection of targets is one of the most attractive applications of WSN in surveillance systems. To resolve the problem of target tracking, it is essential to deploy a system model. It has been observed that clustering algorithms play an important role in cluster head selection, but they consume significant amount of energy. In this paper an energy efficient system model is deployed with a novel target tracking algorithm to track the target around the vicinity of the WSN. As there is more possibility of collision proximate to the base station, a new collision avoidance method is introduced. The lifetime of the network on the basis of congestion around the sink node, packet density and path loss are also measured efficiently.

     

Comparative DC Characteristic Analysis of AlGaN/GaN HEMTs Grown on Si(111) and Sapphire Substrates by MBE

A comparative assessment of AlGaN/GaN high-electron-mobility transistors (HEMTs) grown by molecular beam epitaxy on silicon and sapphire substrates has been carried out. Large-area power GaN HEMTs with identical device dimensions were fabricated on both substrates. A thicker AlN buffer layer was used for the GaN HEMT on silicon to achieve similar quality and uniformity of GaN epitaxy for rational comparison with that grown on sapphire. Direct-current analysis and physical characterization were carried out to understand the performance of the devices. Mathematical measurement of the instability of the current–voltage (I–V) characteristic at high applied drain bias was carried out to evaluate the performance of both devices. An improved two-dimensional (2D) analysis of the I–V characteristic was performed from a thermal perspective including appropriate scattering effects on the 2D electron gas mobility. The experimental and analytical studies were correlated to reveal the effects of temperature-sensitive scattering phenomena on the mobility as well as on the I–V characteristic at high drain bias in terms of lattice thermal heating. It is observed that the HEMT on Si has improved stability compared with sapphire due to its weaker scattering phenomena at high drain bias, associated with its thermal conductivity. Simulation of 2D thermal mapping was also carried out to distinguish the hot-spot regions of the devices. The comparable electrical performance of these devices illustrates the viability of AlGaN/GaN HEMTs on Si(111) to achieve low-cost stable devices with better thermal power handling for high-voltage applications.     

Poly (3‐hydroxybutyrate)/cellulose nanocrystal films for food packaging applications: Barrier and migration studies

This article reports the fabrication of poly (3‐hydroxybutyrate) (PHB)/cellulose nanocrystal (CNC) based nanobiocomposite films with improved gas barrier and migration properties for food packaging applications. Acid hydrolysis of cellulose pulp from bamboo (Bambusabalcooa) yields CNCs with diameter of 15–20 nm and length of 400–600 nm. Evaluation of d‐spacing using XRD indicates intercalation of PHB matrix with CNC at optimum loadings of 2 wt%. Overall migration values in presence of both polar and nonpolar food simulants are found within standard limits. After migration studies on PHB/CNC films, significant decrease in crystallization temperature (by 15°C) is observed, with subsequent presence of multiple melting peaks. The oxygen transmission rate (OTR) decreases significantly (by ～65%), even at low CNC (～2 wt%) loadings. Permeation activation energy (calculated from Arrhenius equation) and barrier properties, such as solubility and diffusivity, improved (decreased by ～57 and 17%, respectively) with loading fractions (～2 wt%) due to the hydrogen bonded interaction of PHB with CNCs as well as tortuous path provided towards oxygen permeation. POLYM. ENG. SCI., 55:2388–2395, 2015. © 2015 Society of Plastics Engineers     

Optimisation of processing conditions for infrared drying of cashew kernels with testa

Cashew kernels are thermally processed to facilitate the removal of their outer skin (testa). Infrared (IR) processing of cashew kernels for differential drying is a novel approach. Processed cashew kernels are valued for their colour, size and texture. The kinetics of colour change and the effect of thermal processing on compressive strength (indicator of brittleness) during IR drying of cashew kernels were investigated. Kernels with testa were dried for different durations (15–55 min) over a range of temperatures (55–95 °C). The change in colour was expressed as total colour difference and browning index. The colour values increased with increasing drying temperature and duration, indicating darkening of the kernel colour. Increase in drying duration reduced the compressive strength, imparting the desired brittleness to the kernel. Optimisation of the drying conditions by response surface methodology and the peelability factor indicated that the best results could be obtained when cashew kernels were dried at 55 °C for 55 min. Copyright © 2004 Society of Chemical Industry     

Coconut Milk and Coconut Oil: Their Manufacture Associated with Protein Functionality

Coconut palm (Cocos nucifera L.) is an economic plant cultivated in tropical countries, mainly in the Asian region. Coconut fruit generally consists of 51.7% kernel, 9.8% water, and 38.5% shell. Coconut milk is commonly manufactured from grated coconut meat (kernel). Basically, coconut milk is an oil‐in‐water emulsion, stabilized by some proteins existing in the aqueous phase. Maximization of protein functionality as an emulsifier can enhance the coconut milk stability. In addition, some stabilizers have been added to ensure the coconut milk stability. However, destabilization of emulsion in coconut milk brings about the collapse of the emulsion, from which virgin coconut oil (VCO) can be obtained. Yield, characteristics, and properties of VCO are governed by the processes used for destabilizing coconut milk. VCO is considered to be a functional oil and is rich in medium chain fatty acids with health advantages.     

基于多项标准的智能电网集成方法

介绍了在设计实施集成配电系统的智能方法时应考虑的主要方面,其中包括:数据采集、监视控制及配电管理系统、停电管理系统与现场服务自动化,以及事故呼叫系统。提出使用IEC61968和公共信息模型等标准实施系统集成。在新老系统之间的集成过程中,这种方法可以有效降低成本,并使集成过程更加简单、快捷。此外,还阐释了目前在行业中存在的问题,提出将电力设备中的信息孤岛集成,讨论了中间件(消息总线)、业务流程自动化和工作流集成,并表明集成过程的标准化需要行业的共同努力。最后,指出集成过程中最重要的要求,并推荐了具体的集成技术和实施方案。     

How to Select Phase Change Materials for Tuning Condensation and Frosting? (Adv. Funct. Mater. 3/2023)

Synthetic surfaces engineered to regulate phase transitions of matter and exercise control over its undesired accrual (liquid or solid) play a pivotal role in diverse industrial applications. Over the years, the design of repellant surfaces has transitioned from solely modifying the surface texture and chemistry to identifying novel material systems. In this study, selection criteria are established to identify bio-friendly phase change materials (PCMs) from an extensive library of vegetable-based/organic/essential oils that can thermally respond by harnessing the latent heat released during condensation and thereby delaying ice/frost formation in the very frigid ambient that is detrimental to its functionality. Concurrently, a comprehensive investigation is conducted to elucidate the relation between microscale heat transport phenomena during condensation and the resulting macroscopic effects (e.g., delayed droplet freezing) on various solidified PCMs as a function of their inherent thermo-mechanical properties. In addition, to freeze protection, many properties that are responsive to the thermal reflex of the surface, such as the ability to dynamically tune optical transparency, moisture harvesting, ice shedding, and quick in-field repairability, are achievable, resulting in the development of protective coatings capable of spanning a wide range of functionalities and thereby having a distinctive edge over conventional solutions.     

Silica Supported Acids (SiO2-HClO4, SiO2-KHSO4) as Eco-Friendly Reuasble Catalysts for Bromination of Aromatic and Heteroaromatic Compounds Using KBr under Solvothermal and Solvent-Free Conditions

Silicon - Silica supported acids like Si-KHSO4, and Si-HClO4 are explored as reusable nano green catalysts for bromination of aromatic and hetero aromatic compounds using KBr under solvothermal,...