Millimeter-wave Substrate Integrated Printed Ridge Gap Waveguide Leaky-Wave Antenna for WiGig Applications

Abstract Millimeter-wave Substrate Integrated Printed Ridge Gap Waveguide Leaky-Wave Antenna for WiGig Applications Mohammad Reza Rahimi, MASc. Concordia University, 2018 Leaky-wave antennas have been an interesting topic for researchers for more than half a century. As millimeter-wave frequencies applications are in high demand for communication companies due their wider bandwidth, designing a leaky-wave antenna, for this frequency range is becoming more challenging with the demand for low-loss and low-cost components. Since high-performance hollow waveguides, as a low loss guiding structure, drives the cost to an unacceptable level and microstrip technology, as a low-cost transition, has an unacceptably high loss. Therefore, the requirements for a new technology that achieves both low cost and high performance feels more tangible. The new technology of substrate integrated printed ridge gap waveguide that was proposed in 2016 shows promising characteristics as a new modified gap waveguide structure for millimeter-wave applications in terms of low insertion loss and low cost. Therefore, it is necessary to propose a new desirable class of microwave components based on this technology. Here, we propose the use of this technology to design three leaky-wave antennas. The work of this thesis is divided into three major parts: (1) designing a periodic structure which has a leaky mode for a specific range of frequencies, and (2) designing a 1D-periodic leaky-wave antenna based on a periodic structure and connecting the antenna to the standard 50 Ω equipment. For achieving this purpose a quasi-TEM transition and a transition from microstrip to substrate integrated ridge gap waveguide has been designed. In addition, the slots of the proposed antenna are designed in order to have an almost constant leakage ratio through the whole operating frequency band. (3) The third part will discuss a linear array of the proposed antenna in which a new termination has been considered which results in a shorter physical length. The proposed antennas can be easily fabricated with a low-cost multi-layered PCB technology. In addition, all these antennas designed for the WiGig applications which are more attractive for today's requirements. Keywords: Leaky-wave antenna; gap waveguide; electromagnetic band ga

Adsorption of lead by Microalgae Chaetoceros Sp. and Chlorella Sp. from Aqueous Solution

Introduction: Using bio-sorbents is regarded as one of the effective methods to remove heavy metals. Therefore, this study aimed to investigate Pbadsorption from contaminated water by Chaetoceros sp. and Chlorella sp. algae. Materials &Methods: This experimental study was conducted in a batch reactor. The amount of Pbadsorption by Chaetoceros sp. and Chlorella sp. algae was studied under such conditions as different adsorbent dosages (0.2, 0.5, 1.5 and 2 g/L), different pH (3, 4, 5, 6, 7, 8), different temperatures (20, 25, 30, 35, 40 °C), different contact times (30, 60, 90, 180, 360 minutes), different particle sizes (20, 40, 60, 100, 140 mesh) and different Pb concentrations(20, 40, 60 mg/L). Then adsorption isotherms and kinetic models of metal ions were determined based on Langmuir and Freundlich isotherms as well as first and second order kinetic models. Results: The efficiency of Pb removal by Chlorella sp. and Chaetoceros sp. algae was reported 78% and 60% respectively. The maximum adsorption was observed at optimal conditions including 25°C, pH of 6, 180 minutesof contact time, particle size of 20 mesh, 1.5 gr/L of adsorbent and 20 mg/L concentration of Pb.Chlorella algae was observed to remove Pb more than Chaetoceros algae. Based on the study results, Pbadsorption by Chlorella algae complies with Langmuir adsorption isotherm model, whereas Chaetoceros algae follows Freundlich model. The kinetic models of algae adsorption followed a second order equation. Conclusion: The study findings revealed that Chlorella algae can be effectively used in order to adsorb Pb from contaminated water due to its high efficiency of Pb adsorption

Potential Negative Impacts of Social Inequality on Visual Health: the Possible Pathophysiology Mechanisms

Letter/ No abstrac

Immunization following hepatitis B mass vaccination in the 18 years old students in Chaharmahal va Bakhtyari province in Iran

Background and aims: The main objective of immunization by hepatitis B vaccine is to generate adequate concentration of anti hepatitis B antibody (HBsAB) in the serum. This study was aimed to determine the effectiveness of hepatitis B vaccination campaign in 18 years old students in Chaharmahal va Bakhtiari province. Methods: In a cross- sectional study, 360 students with 18 years old (born in 1989) and have taken 3 doses of hepatitis vaccine in national vaccination campaign in 2007, were selected by cluster sampling. This study was performed in 2008 in Chaharmahal va Bakhtiari province in the central of I.R of Iran. The level of hepatitis B antibody was detected by quantitative ELIZA method using Dialab Kit. The collected data was analyzed using SPSS 16.0 software by X2 and t-test. Results: Of 360 students, 164(45%) cases were male and 174 (48/3%) cases were from urban areas. Just 349 students (96/95%) have acceptable immunization responses, (In those anti hepatitis B antibodies were more than 20 IU/ml). There was no significant relationship between the level of antibody and variables such as: sex, born places, smoking, contact history, previous disease and Hejamat (P>0.05). Conclusion: Considering the results of the present study and previous researches from others countries, we can emphasize that the mass vaccination has been effective in those 18 years old students and we can be sure that the vaccination has been performed perfectly in Chaharmahal va Bakhtiari province

Dissection of the genetic basis of genotype-by-environment interactions for grain yield and main agronomic traits in Iranian bread wheat landraces and cultivars

Understanding the genetic basis of performance stability is essential to maintain productivity, especially under severe conditions. In the present study, 268 Iranian bread wheat landraces and cultivars were evaluated in four well-watered and two rain-fed conditions for different traits. According to breeding programs, cultivars were in a group with a high mean and stability in terms of GY, GN, and SW traits, while in terms of PH, they had a low mean and high stability. The stability of cultivars and landraces was related to dynamic and static stability, respectively. The highest number of marker pairs and lowest LD decay distance in both cultivars and landraces was observed on the B genome. Population structure differentiated indigenous cultivars and landraces, and the GWAS results for each were almost different despite the commonalities. Chromosomes 1B, 3B, 7B, 2A, and 4A had markers with pleiotropic effects on the stability of different traits. Due to two rain-fed environments, the Gene Ontology (GO) confirmed the accuracy of the results. The identified markers in this study can be helpful in breeding high-performance and stable genotypes and future breeding programs such as fine mapping and cloning

An investigation into the effect of Likert's leadership styles on empowering Iran insurance company's staff

This case study was carried out in Iran Insurance Company in the area of Hamadan city in September, 2013. The statistical population of the study consisted of 144, the whole body of which was taken as sample to raise more accuracy and have access to it. The sampling method is of simple randomized kind. The means of collecting data is questionnaire. In order to assess the validity of the questionnaire, the formal method was used as Cronbach Alpha with 83.0 and 75.0 values was taken for its reliability. The results showed that main hypothesis about the significant relationship between Likert leadership styles and empowering staff is confirmed. These breakthroughs revealed that empowering staff can be developed

Unstabling in the legal Environment and Decision-Making process

The aim of this study was to determine the impact of change dimensions in the legal environment on the quality of each stage of the decision-making process of the senior managers of public institutions. The interest population of this study included all general managers, directors, administrative, financial and support assistants, financial controllers and managers and other executive directors and deputies of Zanjan province that were studied by census method. The data collection toll was a researcher-made questionnaire that its reliability and validity were confirmed (Cronbach's alpha coefficient: 0.87). Data analysis was performed using descriptive statistics and inferential statistics techniques (Chi-square test and Friedman test) by SPSS software. The results show that the dimensions of changes in the legal environment factors affect on the two first and third stages of the decision making process of managers (stages of data collection, decision-making and its implementation). However, it has no effect of the data and information analysis stage