Anisotropic diffusion for noise removal of band pass signals

A noise removal method for band pass signals based on the anisotropic diffusion algorithm originally put forward by Perona and Malik is proposed in this paper. The anisotropic smoothing algorithm proposed here is for band pass signals modulated with a constant carrier frequency. A partial differential equation to smooth band pass noisy signals is derived. The propagator of this differential equation is also analytically calculated in this paper. An appropriate linear operator is then considered here for such band pass signals to form an anisotropic diffusion algorithm. The algorithm proposed here demonstrates better performance for band pass noisy signals containing discontinuities in comparison with the traditional Perona-Malik (PM) algorithm and is robust in the presence of excessive noise with SNR less than unity.     

Tungsten Lamps as an Affordable Light Source for Testing of Photovoltaic Cells

An improved Tungsten light source system for photovoltaic cell testing made from low-cost, commercially available materials is presented as an alternative to standard expensive testing equipment. In this work, spectral correction of the Tungsten light source is achieved by increasing the color temperature to ??5200 K using inexpensive commercially available filters. Spectral measurements of the enhanced light source reveal that a better spectrum match towards the solar spectrum is achieved than what has been previously demonstrated. Specifically, the improved solar spectrum match is achieved by substantial filtering of the infrared range. The proposed setup is used to evaluate the performance of both silicon and organic based photovoltaic cells.     

Link technologies and BlackBerry mobile health (mHealth) solutions: a review

The number of wearable wireless sensors is expected to grow to 400 million by the year 2014, while the number of operational mobile subscribers has already passed the 5.2 billion mark in 2011. This growth results in an increasing number of mobile applications including: Machine-to-Machine (M2M) communications, Electronic-Health (eHealth), and Mobile-Health (mHealth). A number of emerging mobile applications that require 3G and 4G mobile networks for data transport relate to telemedicine, including establishing, maintaining, and transmitting health-related information, research, education, and training. This review paper takes a closer look at these applications, specifically with regard to the healthcare industry and their underlying link technologies. The authors believe that the BlackBerry platform and the associated infrastructure (i.e., BlackBerry Enterprise Server) is a logical and practical solution for eHealth, mHealth, sensor and M2M deployments, which are considered in this paper.     

A design method for substrate integrated waveguide electromagnetic bandgap (SIW-EBG) filters

An efficient design method for substrate integrated waveguide electromagnetic bandgap (SIW-EBG) filters is proposed which provides direct dimensional synthesis approach for desired filter objectives without using network representations. The method is applied to the design of an X band SIW-EBG filter and its response is compared with HFSS (high frequency structure simulator) simulations for validation purposes. Fairly good agreement between the results shows the applicability of the proposed method for SIW-EBG filter design.     

红外通信IrDA标准与应用

红外光是有许多优势的通信媒介，红外通信IrDA标准是目前IT和通讯业普遍支持的近距离无线数据传输规范。本文介绍了红外通信IrDA标准的内容以及它的物理层协议，脉冲调制的必要性，不同传输速率下不同的脉冲调制方式，连接建立协议层的帧结构。给出了符合IrDA标准的芯片TOIM32325和TFDS4500在高电压环境下调试实验设备的应用。     

Experimental investigation of liquid–liquid flow in an inclined pipe using dimensionless numbers

Two-phase flow is a common phenomenon in the energy industry, where flow patterns significantly affect heat transfer and pressure drop in different systems. However, there is no unique or comparable flow map because of its dependency on dimensional parameters. Therefore, an analysis using dimensionless numbers makes the results comprehensive. To do so, a series of liquid–liquid flow experiments (1296 experiments) were conducted in a transparent pipe at the different velocities of the phases. The flow patterns were captured using a high-speed camera. The experiments were performed at eight different inclinations within the range of −20 to +20 degrees. Six flow patterns are observed at different inclinations; stratified flow with mixing at the interface (STMI), dispersion of water in oil (Dw/o), dispersion of oil in water (Do/w), dual continuous (DC), slug, and wavy stratified (WST), where the first five flow patterns are presented in the upward flow and the two last flow patterns disappear in some of the downward flow. The pattern of boundaries for each flow pattern in the upward flow shows dependency on inclination, while in the downward flow condition, a rather general format can be applied to most of the patterns. The analysis illustrates that gravity and buoyancy forces are the dominating forces in the system compared to other forces, such as viscous, inertia, and interfacial tension, which are due to the inclination of the pipe.     

Polystyrene/Polyolefin Elastomer Blends Loaded with Halloysite Nanotubes: Morphological,Mechanical, and Gas Barrier Properties

Herein, a simple melt-blending method is utilized to disperse of halloysite nanotubes (HNTs) in polystyrene/polyolefin elastomer (PS/POE) blends. Based on morphological studies, the PS/POE/HNT nanocomposite containing up to 3 phr HNTs shows excellent nanofiller dispersion, while those filled with 5 phr HNTs exhibit nanofiller aggregation. To overcome the nanofiller aggregation issue, the polypropylene-grafted-maleic anhydride (PP-g-MA) compatibilizer is added to the PS/POE/HNT nanocomposite, which results in improved mechanical properties for the nanocomposite sheets. Furthermore, the addition of compatibilized HNTs to the PS/POE blends leads to decreased O₂ and N₂ gas permeabilities. Besides, incorporating POE, HNTs, and PP-g-MA leads to a decrease in water vapor transmission of PS. In the end, the experimentally-determined mechanical properties and gas permeabilities of the nanocomposite sheets are compared to those predicted by prevalent theoretical models, revealing a good agreement between the experimental and theoretical results. Molecular-dynamics simulations are also carried out to calculate the gas diffusion coefficients in the different sheets to further support the experimental findings in this study. Overall, the PS/POE/HNT/PP-g-MA nanocomposite sheets fabricated in this work demonstrate excellent mechanical and gas barrier properties; and hence, can be used as candidate packaging materials. However, the strength of the resulting PS/POE blend may be inferior to that of the virgin PS.     

Molecular dynamics simulations of vinyl ester resin monomer interactions with a pristine vapor-grown carbon nanofiber and their implications for composite interphase formation

A molecular dynamics simulation study was performed to investigate the role of liquid vinyl ester (VE) resin monomer interactions with the surface of pristine vapor-grown carbon nanofibers (VGCNFs). These interactions may influence the formation of an interphase region during resin curing. A liquid resin having a mole ratio of styrene to bisphenol-A-diglycidyl dimethacrylate VE monomers consistent with a commercially available 33 wt.% styrene VE resin was placed in contact with both sides of two pristine graphene sheets overlapped like shingles to represent the outer surface of a pristine VGCNF. The relative monomer concentrations were calculated in a direction away from the graphene sheets. At equilibrium, the styrene/VE monomer ratio was higher in a 5 Å thick region adjacent to the nanofiber surface than in the remaining liquid volume. The elevated concentration of styrene near the nanofiber surface suggests that a styrene-rich interphase region, with a lower crosslink density than the bulk matrix, could be formed upon curing. Furthermore, styrene accumulation in the immediate vicinity of the nanofiber surface might, after curing, improve the nanofiber–matrix interfacial adhesion compared to the case where the monomers were uniformly distributed throughout the matrix.     

Effect of Different Cosolvents on Transesterification of Waste Cooking Oil in a Microreactor

Biodiesel was prepared from waste cooking oil combined with methanol. The process was performed via transesterification in a microreactor using kettle limescale as a heterogeneous catalyst and various cosolvents under different conditions. n‐Hexane and tetrahydrofuran were selected as cosolvents to investigate fatty acid methyl esters (FAMEs). To optimize the reaction conditions, the main parameters affecting FAME% including reaction temperature, catalyst concentration, oil‐to‐methanol volumetric ratio, and cosolvent‐to‐methanol volumetric ratio were studied via response surface methodology. Under optimal reaction conditions and in the presence of the cosolvents n‐hexane and tetrahydrofuran, high FAME purities were achieved. Considering the experimental results, the limescale catalyst is a unique material, and the cosolvent method can reduce significantly the reaction time and biodiesel production cost.     

喷丸强化对合金化奥贝球铁疲劳性能的影响

喷丸处理是改进金属工件疲劳性能最常规的表面处理方法。文中研究了喷丸处理对合金化奥贝球铁(AD)I疲劳性能的影响。等温淬火包括875℃保温90 min奥氏体化处理,然后在320℃、365℃和400℃进行等温处理。用直径0.4～0.6 mm的丸喷丸后的试样做旋转弯曲疲劳试验。对试样进行XRD和SEM分析,测定显微硬度和粗糙度,研究试样的疲劳性能。结果表明,在320℃、365℃和400℃等温处理的试样喷丸后疲劳强度分别增加了27.3%、33.3%和48.4%。