A New Class of Dual-mode Substrate Integrated Waveguide (SIW) Filter with Two Metalized Posts

This paper presents the investigation and characterization of dual-mode Substrate Integrated Waveguide (SIW) filter with two metalized posts on the cavity to reduce the overall volume of RF front-end subsystems. By introducing two vertical metalized posts and two diagonal metalized posts in dual-mode SIW filter, both SIW filters show different flow of Electromagnetics (EM) can be identify from the E-fields. In order to compare which dual-mode SIW filter gives the better performance, the designs are simulated at centre frequency 2 GHz using CST Studio Suite software and the results are validate through measurement. The measurement shows a good agreement with the simulated results. This design is suitable for any integration microwave system where the reduced complexity of the design and cost as well as weight is very important for the wireless communication systems

The Development of Wireless Power Transfer Technologies for Mobile Charging in Vehicles using Inductive Approach

Nowadays, the mobile charging in vehicle is a must and therefore, such technology is now available in every vehicle through wired connection approach. Using this wired connection to power up mobile device in the vehicle might be inconvenience to the user. Thus, this project aims to develop a wireless power transfer technology to power up the mobile device in a vehicle. Through this, the users will not facing difficulty of charging their device while driving. To be specific, the Inductive Power Transfer (IPT) is applied here due to its advantages where it can transfer power wirelessly with a higher efficiency in a short range. To make this work, a Class E inverter is designed to convert a direct current (DC) supply into alternating current (AC) supply at a high frequency with a higher efficiency. Furthermore, pi-2-a impedance matching circuit is also applied in this work in order to improve the efficiency of such system. To validate the efficiency of the proposed method, analysis on the gap distance between the two magnetic coils, transmitter and receiver, are performed through simulation and experimental work. At the end of this work, the designed prototype is able to yield approximately 70 % in terms of output efficiency and able to power up the mobile device wirelessly

Influence of modified air on combustion characteristics in meso-scale vortex combustor

The need to supply power for miniaturized mechanical devices opens exciting new opportunities for combustion, especially in the field of micro-power generation. Because of the need for power supply devices with high-specific energy (small-size, low weight, long duration) and power. Meso/micro scale combustion has been considered as a potential solution for many small-volumes and energy demanding systems, such as power supplies for portable device. In this study the structure of turbulent diffusion flames in a meso scale combustor with different oxygen concentration has been investigated using a new design of vortex combustor. Methane gas was used as a fuel. Numerical investigations have been performed on the temperature distribution, swirl number, heat loss, and emitter efficiency in vortex combustion. The results have been obtained for various O2 concentrations in the air as oxidizer. The results shows that thermal flame behaves depend strongly on the oxygen content in the oxidizer. When the oxygen concentration increases from 15% to 30%, the flame temperature of the meso-combustion rises in all cases. Emitter efficiency is very high in the meso-combustor with high O2 concentration in oxidizer

Development of Wireless Power Transfer using Inductive Approach to Power Up Multiple Low Power Devices

Wireless power transfer (WPT) is a technology that implements non-contact power transmission within a distance. There are three types of wireless power transfer, which are inductive power transfer (IPT), capacitive power transfer (CPT), and acoustic power transfer (APT). Among these three types of wireless power transfer, the inductive power transfer has advantages in term of the transmission distance and high efficiency. Therefore, we focused on the inductive power transfer to develop a wireless charging to power up multiple low power devices. In this work, we implemented the IPT method to power up multiple devices on the office table. This IPT system enabled the power transmission from the office table to the several loads that has been attached together with the receiver coil. Hence, electronic appliances such as table clock and desk lamp (used in this work) will operate without using a wire to get a power source from power outlet or a battery. To be more specific, in this work, a high efficiency Class-E converter was designed to convert the DC source into AC. Through this, the efficiency of the system can be improved. Finally, the developed prototype was able to power up desk lamp and digital clock wirelessly with 70% efficiency. The performances analysis of the developed prototype is discussed and the future recommendation of this technique is also presented in this pape

Effect of corrugated minichannel variable width on entropy generation for convective heat transfer of alpha-Alumina-water nanofluid

Energy management and sustainability in thermal systems require maximum utilization of resources with minimal losses. However, it is rarely unattainable due to the ever-increasing need for a high-performance system combined with device size reduction. The numerical study examined convective heat transfer of an alpha-Alumina-water nanofluid in variable-width corrugated minichannel heat sinks. The objective is to study the impact of nanoparticle volume fractions and flow area variation on the entropy generation rate. The determining variables are 0.005 – 0.02 volume fractions, the fluid velocity 3 – 5.5 m/s and heat flux of 85 W/cm2. The numerical results show an acceptable correlation with the experiment results. The results indicate the thermal entropy production drop with an increase in nanoparticles volume fraction. Contrastingly, the frictional resistance entropy suggests the opposite trend due to the turbulence effect on the fluid viscosity. The induction of Alumina-Water nanofluid with enhanced thermal conductivity declined the entropy generation rate compared to water alone. The increase in width ratio by 16% between the cases translates to at least a 9% increase in thermal entropy production. The outcome of this study can provide designers and operators of thermal systems more insight into entropy management in corrugated heatsinks

Nonpulmonary Outcomes of Asbestos Exposure

The adverse pulmonary effects of asbestos are well accepted in scientific circles. However, the extrapulmonary consequences of asbestos exposure are not as clearly defined. In this review the potential for asbestos to produce diseases of the peritoneum, immune, gastrointestinal (GIT), and reproductive systems are explored as evidenced in published, peer-reviewed literature. Several hundred epidemiological, in vivo, and in vitro publications analyzing the extrapulmonary effects of asbestos were used as sources to arrive at the conclusions and to establish areas needing further study. In order to be considered, each study had to monitor extrapulmonary outcomes following exposure to asbestos. The literature supports a strong association between asbestos exposure and peritoneal neoplasms. Correlations between asbestos exposure and immune-related disease are less conclusive; nevertheless, it was concluded from the combined autoimmune studies that there is a possibility for a higher-than-expected risk of systemic autoimmune disease among asbestos-exposed populations. In general, the GIT effects of asbestos exposure appear to be minimal, with the most likely outcome being development of stomach cancer. However, IARC recently concluded the evidence to support asbestos-induced stomach cancer to be “limited.” The strongest evidence for reproductive disease due to asbestos is in regard to ovarian cancer. Unfortunately, effects on fertility and the developing fetus are under-studied. The possibility of other asbestos-induced health effects does exist. These include brain-related tumors, blood disorders due to the mutagenic and hemolytic properties of asbestos, and peritoneal fibrosis. It is clear from the literature that the adverse properties of asbestos are not confined to the pulmonary system

Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

Investigations on Capacitor Compensation Topologies Effects of Different Inductive Coupling Links Configurations

<p>This paper presents investigations on capacitor compensation topologies with different inductive coupling links for loosely coupled inductive power transfer (IPT) system. In general, the main constraint of the loosely coupled IPT system is power losses due to the large leakage inductances. Therefore, to overcome the aforementioned problem, in this work, capacitor compensation is proposed to be used by adding an external capacitor to the system. By using this approach, the resonant inductive coupling can be achieved efficiently and hence the efficiency of the system is also increased significantly. This paper analyzes the performance of two different compensation topologies, which are primary series-secondary series (SS) and primary series- secondary parallel (SP) topology. The performance of such topologies is evaluated through the experimental results at 1MHz operating frequency for different types of inductive coupling. From the results, SS topology produces a high power transfer but SP topology gives better efficiency.</p