DESIGN OF LOWPASS FILTER WITH LOW TOTAL HARMONIC DISTORTION

This research is conducted to design a lowpass filter with low total harmonic distortion (THD). The research focuses on the suitable design synthesis of lowpass filter with cutoff frequency at 500kHz, -35 dB attenuation at 1000kHz and -100 dB response of total harmonic distortion. Elliptic filter topology is selected after comparing with Maximally flat, Chebyshev and Inverse Chebyshev topologies because Elliptic filter gives steepest attenuation and lowest THD reading. Elliptic filter results in lowest THD at -35.65 dB. Additionally, research was done on the effect of inductor’s number and types on the harmonic responses of filters. Comparison of inductors and capacitors were made and the best component with expected lowest THD was selected for fabrication. Therefore Ferrite pot core inductor and Polystrene film capacitor was selected. Stated design hypothesis is the design of lowpass filter with low THD is possible with less inductor section

Preliminary study on tensile and impact properties of kenaf / bamboo fiber reinforced epoxy composites

The application of natural fibers as reinforcement in composite material has increased due to environmental concerns, low cost, degradability and health concerns. The purpose of this study is to identify the best type of bamboo fibers to be used as reinforcement for kenaf (K)/bamboo hybrid composite. There were three types of bamboo fibers evaluated in this study which include bamboo mat (B), bamboo fabric (BF) and bamboo powder (BP). Chemical composition of B, BF, BP and K fibers were analyzed in this study. The effect of different types of bamboo fibers on tensile, impact, and morphological properties were investigated. The B/epoxy composites displayed the highest tensile strength (53.03 MPa) while K/epoxy composite had the highest tensile modulus (4.71 GPa). Scanning electron micrographs of B/epoxy composites displayed better fiber/matrix interfacial bonding in comparison to other studied composites. Results showed that impact strength of BF-based composite was highest (45.70 J/m). In conclusion, the tensile strength of B/epoxy composite is superior to the other bamboo reinforced composites and will be further evaluated in the next study

Design of The Mechanism for Auto Release Seat Belt in End-Button Release Buckle

This project revolves around the buckle of a seat belt, mainly push end release button type, where a feature was created to make it into an auto release seat belt through designing the mechanism within the buckle. The aim of the project is to design the mechanism part of a convertible end button release seat belt buckle, to simulate the designed mechanism part of the convertible auto release seat belt for vehicle cars and to analyze the designed mechanism regarding the effectiveness when installed. 3 different models of solenoid-triggered-parts were designed where Model 1 has no support on its side, presence of fillet and smallest surface area for the base. As for Model 2 and 3, there were no fillet used, presence of support of the side and Model 2 has larger surface area for the base, but Model 3 has the largest amongst the three models. The parameter of this project was the material used when running the simulation which is Polyphenylene Ether (PPE). Through the simulation results, a final model was designed consists of features such as, having support on the side, largest surface area for the base and presence of fillet as these features has shown the best results through the simulation. As for the conclusion, the study managed to achieve all of the objectives which are, the auto release mechanism was designed and simulated successfully using SolidWorks, and it was simulated through simulation within the software

Fistule aorto-dudoénale après pose de prothèse vasculaire aortique : une observation clinique inhabituelle: Aortoduodenal fistula following aortic prosthesis. An uncommon case report

Secondary aortodigestive fistula is a rare and life-threatening long-term complication of abdominal aortic surgey. The diagnosis of gastrointestinal bleeding secondary to aortoduodenal fistula is often difficult in practice. The interval between first intervention and developpement of the fistula can vary from months to years. We report a case of a patient with aortic prosthesis who was admitted for gastrointestinal bleeding secondary to aortoduodenal fistula. Les fistules aorto-digestives constituent une complication rare mais gravissime des prothèses aortiques. L’intervalle de temps entre la mise en place de la prothèse et la survenue de cette complication, varie de quelques mois à quelques années. Le diagnostic des hémorragies digestives sur fistule aorto-duodénale est souvent difficile. Dans ce cas clinique, nous présentons un patient avec prothèse aortique hospitalisé pour hémorragie digestive

Educational software for stress analysis of idealized multi-spar aircraft wing

The cross-section of a wing carries stresses such as bending, torsional and shear. The analysis in aircraft structure courses is done by assuming bending stress is only assumed to affect boom areas while shear stress only affects the skins of the cross-section. A MATLAB software has been developed with the purpose to compute the stresses and the shear centre of the cross-section. The software includes choices for tapered or non-tapered wingspan, boxed or curved leading edge, and with or without extra booms. The software is validated with some literature problems, the comparison shows low percentage difference between the two

Robotic-Assisted Versus Open Techniques for Living Donor Kidney Transplant Recipients: A Comparison Using Propensity Score Analysis

Background: Following the rapid advancements in minimally invasive urology, living donor robotic-assisted kidney transplantation (RAKT) has developed into a feasible alternative to open kidney transplantation (OKT). The procedure has been performed in multiple international programs, but a relative dearth of experience exists in the US. In this investigation, we compare RAKT to OKT using a propensity score analysis, to elucidate the safety and feasibility of RAKT as a suitable alternative to OKT. Methods: A retrospective review of 101 living kidney transplants (36 RAKT, 65 OKT), which occurred between January 2016 and June 2018, was conducted. Selection for RAKT was based on Robot availability. Recipient and donor demographic variable were collected, in addition to perioperative parameters. A propensity score analysis was conducted, matching for recipient age, gender, body mass index, race, pre-operative dialysis, preoperative serum creatinine, panel reactive antibody, and donor age. Primary outcomes assessed included perioperative factors such as estimated blood loss (EBL), cold ischemic time (CIT), warm ischemic time (WIT), operative time, as well as several patient outcomes including, length of stay, narcotics consumed on postoperative days one and two, and change in serum creatinine (SCr) at five time points (day 3, day 7, day 14, 6 months, and 1 year). Final analysis included 35 patients in each group. Results: Recipients’ (N=101) mean age was 49 years (range 19-74), with RAKT recipients slightly younger than OKT recipients (46 vs 51 years). 61 recipients were male and 62 white (29 Black, 10 other). Average recipient BMI was 29 (range 20-40), with equivalent BMIs in RAKT and OKT subsets. Following propensity score analysis, RAKT recipients demonstrated significantly greater WIT (49 vs 38 minutes, p\u3c0.001) and less EBL (62.5 vs 150 mL, p\u3c0.001). However, total operative time and overall length of stay were not significantly different in the groups. Postoperative narcotics consumed on postoperative days one and two were similar between the groups (31.8 vs 32.3 morphine equivalents). Additionally, SCr was evaluated at days 3, 7, and 14 as well as 6 months and 1 year, without significant differences between the groups. Conclusion: RAKT offers an important minimally invasive alternative to OKT, with a short learning curve, and similar graft and patient outcomes. Notably, this study compares RAKT to OKT with a heterogeneous study population, using propensity scoring. The largest limitation of this study is a small sample size. Interestingly, despite the significantly longer WIT in RAKT, we found an equivalence of SCr between groups in the early and intermediate postoperative period. Although the small sample size limits our ability to detect differences in graft and patient outcomes, trends demonstrate shorter lengths of stay, shorter operative times, and smaller amounts of blood loss for RAKT recipients. Additionally, trends demonstrate fewer narcotics administered by the second postoperative day. Similar to the advent of laparoscopic technology in living donor nephrectomy, early findings in RAKT demonstrate a safe and reasonable alternative for living donor kidney transplantation in various populations.https://scholarlycommons.henryford.com/merf2019clinres/1052/thumbnail.jp

Phytoremediation efficiencies of Spirodela polyrhiza and Brassica oleracea in removing nutrients from treated sewage effluent

The study investigates the capacity of phytoremediation as a post-treatment step for the nutrientrich- treated sewage effluent from Saga City sewage treatment plant, Saga, Japan. Phytoremediation in the context of this study is the removal of nutrients such as ammoniacal nitrogen, nitrate nitrogen and phosphorus from the nutrient-rich-treated sewage effluent by plants. In this study, Spirodela polyrhiza (S. polyrhiza) and Brassica oleracea (B. oleracea) were used to phytoremediate the treated sewage effluent collected from the Saga City Sewage Treatment Plant under laboratory scale. Plants were grown in polypropylene planter box supplied with 8,000 mL treated sewage effluent under indoor environment and full water retention throughout the experimental studies. The removal efficiency and daily absorption of nutrients by phytoremediation plants were determined. It was found that the most optimal removal efficiency and average daily nutrient removal rate by S. polyrhiza throughout the experiment were 92.42% ± 1.29% or 15.4 mg/L/d for ammoniacal nitrogen achieved in day 1, 78.69% ± 10.31% or 2.68 mg/L/d for nitrate-nitrogen achieved in day 4, and 93.45% ± 3.26% or 0.51 mg/L/d for phosphorus in day 3 of an experiment. On the other hand, the removal efficiency and average daily nutrient removal rate by B. oleracea throughout the experiment gave a total of 8 d where 76.07% ± 10.38% or 1.68 mg/L/d for ammoniacal nitrogen, 78.38% ± 0.40% or 1.19 mg/L/d for nitrate-nitrogen and 67.40% ± 10.91% or 0.10 mg/L/d for phosphorus. The overall findings demonstrated that phytoremediation by S. polyrhiza was far more effective in removing nutrients from the nutrient-rich-treated sewage effluent compared to B. oleracea. The significance of the study includes reducing the possibility of eutrophication outbreak caused by the disposal of treated sewage effluent, advocating less dependency on global demand for non-renewable phosphorus resources in the agriculture sector, and solving food demand due to the increasing world population

Strengthening user authentication for better protection of mobile application systems

For most of us now, life is incomplete if living without mobile phones. This is because mobile phones are like a necessity to many people nowadays. Statistics have shown that more than seven billion people in the world are having these devices in 2015. This also means 97% of the human world populations are actually mobile phone users. Besides, more than 50% of the mobile phone users are using smarts phones which are capable of downloading a lot of mobile application systems (apps). It is estimated that more than 200 million apps are being downloaded in 2007 and this number is believed to be growing. Unfortunately, many of these apps involve the transfer of important and confidential personal data or business information. How to ensure this sensitive information is well protected from being stolen or misused by unauthorized parties? One of the ways to secure this communication is to properly control the access to the system by strengthening the user authentication. Thus, this paper focuses on one the techniques to enhance the protections of mobile apps to prevent intrusions by unpermitted users. The enhancement is focusing on improving the multi-factor elements and the text ciphering technique of the user authentication. In this study, random number and time are added in the existing text-based multifactor user authentication. Besides, encryption and hash are used as the text ciphering technique to improve the protection. To measure how secure the proposed enhancement is, an independent testing body has been appointed to perform Vulnerability Test and Functionality Test to the apps. If all these tests are passed, it can be said that the proposed enhancement is strong enough to protect the apps from being intruded. Based on the test results provided by the testing body, CyberSecurity Malaysia, the apps has passed all the Vulnerability Test and Functionality Test. This shows that the control of the access to these apps are strong and able to prevent from being accessed by unpermitted users. This also means the proposed enhancement is able to give better protections to ensure the mobile apps can't be easily broken into by unauthorized mobile phone users