The Design of Novel Transparent Heat Mirrors for Enhanced Solar Thermal Applications

Herein the design of transparent heat mirrors for enhanced solar thermal applications is presented. Dielectric mirrors are considered to function as infrared mirrors that reduce heat losses in the receiver of solar concentrators. The alternating layers have been designed to selectively reflect light strongly over the infra-red spectral region while being highly transmissive towards solar irradiance. This is achieved by designing the interfaces between the high- and low- index films within the dielectric mirror to have a graded refractive index profile. Three different graded index profiles are considered including: 1. a linear index variation, 2. a cubic index variation and 3. a quintic index variation. The effects of altering the dielectric mirror parameters on its performance are investigated. Accordingly, the sensitivity of the transmittance and reflectance spectra of the dielectric mirror towards its number of layers, resolution of the refractive index profiles, refractive index, number of stacked dielectric mirrors, absorption, and incident angle of the incoming light is analyzed. Results show that a single stack infrared dielectric mirror coated on top of the receiver of a solar concentrator system operating at 500 K can increase its power electric generation by more than 60 % and using a triple stack design can increase the power by more than 100 %. Furthermore, considering a typical Dish-Sterling system operating at a temperature of T=1000 K, the electricity generated can be increased by ~ 30 % by coating the receiver within the system with the transparent heat mirrors designed in this work

Evaluating the Frequency of Postoperative Fever in Patients with Coronary Artery Bypass Surgey

<p><strong>BACKGROUND</strong>: Nowadays, coronary artery bypass graft (CABG) is a frequent surgery in treatment of coronary artery disease. According to high expense of this surgery and its important role in patients&rsquo; quality of life, high survival rate of patients and success of surgery are necessary.<strong> </strong>The aim of this study was the evaluation of fever incidence (febrile events) due to incidence of pneumonia, wound infection, bacteremia, urinary tract infection and inflammatory response without infection after CABG.</p> <p><strong>METHODS</strong>: In an intergrades descriptive-analytical study, 107 patients who underwent coronary artery bypass graft (CABG) were enrolled in the study.</p> <p>The patients then were examined by the febrile events and also their characteristics including age, sex, duration of surgery, underlying diseases, and frequency distribution of antibiotics consumptions in pre-surgical and postsurgical periods, and incidence of infectious syndromes.</p> <p><strong>RESULTS</strong>: Frequency distribution of febrile events after CABG was 29.9 percent. The most common administered antibiotic before the surgery was cephalothin (Keflin) and then, cefazolin. The most common administered antibiotic after the surgery was cephalothin (Keflin) and cephalexin (47.7%) and then, cephalothin-gentamicin-cephalexin (31.8%). The average age of patients without febrile syndrome was 60.53 years and in those with febrile syndrome was 59.31 years. In terms of gender, 74.8% of the patients were males. So that 32.5% of males and 22.2% of females had fever. The incidence time of fever in most cases was in the postoperative fourth day. In terms of underlying diseases, 13 percent of them had hypertension and hyperlipidemia, 14 percent had only hypertension, 11.2 percent had only hyperlipidemia and 6.5 percent had diabetes.</p> <p><strong>CONCLUSION</strong>: This study showed that the prevalence of fever in patients undergoing CABG was 29.9 percent and the most common cause of fever was sternal infections. There was a significant correlation between administered antibiotics in preoperative and postoperative periods and febrile syndrome.</p> <strong>Keywords</strong>: Antibiotic, Infection, Coronary Artery Bypass Graft, Feve

The role of media in attracting audiances for public library:A case study on public libraries of Tehran (I.R.Iran)

This study was aimed to evaluate the role of advertising in attracting audience for libraries affiliated to Iranian public libray institute based on the AIDA model in Tehran. This study was applied in terms of purpose and was analytical-survey research from the field studies branch in terms of the method. This study was conducted based on the AIDA model and the population consisted of members of public libraries affiliated to Tehran public library institute during the period from October 2015 to October 2016. The total number of public libraries\u27 members in Tehran was 39085 people. 379 people were selected as the sample based on the Cochran formula. The sampling method was stratified random based on the education component. The data were collected using a researcher-made questionnaire by modeling Jamili brothers, Rabiee and Mohammadian questionnaire (2011). The data were analyzed by SPSS Softwwere in two levels of descriptive and inferential statistics. 338 questionnaires were returned from 379 studied samples. The results showed that advertising of Iranian public libraries was fauiled to pass the levels of AIDA model in Tehran. But it had the effectiveness lower than average. The results show that unawwereness of community about the libraries with diverse services and easy use has led to a gap between libraries and community in general and potential users in particular. One of the essential causes of the advertising inefficiency was excessive concentration of advertising on the library itself (location). The opinions of the public libraries\u27 members in Tehran city show that unawwereness about the existence of the library and the various services that can be provided even has led to a gap among members. Therefore, Iranian public library institute in general, provincial general offices and cities secondarily, and in particular libraries themselves should use all their facilities to remove the barriers of the distance between the referees and the libraries. This problem can be solved to a large extent by extensive advertising

The role of media in attracting audiances for public library:A case study on public libraries of Tehran (I.R.Iran)

This study was aimed to evaluate the role of advertising in attracting audience for libraries affiliated to Iranian public libray institute based on the AIDA model in Tehran. This study was applied in terms of purpose and was analytical-survey research from the field studies branch in terms of the method. This study was conducted based on the AIDA model and the population consisted of members of public libraries affiliated to Tehran public library institute during the period from October 2015 to October 2016. The total number of public libraries\u27 members in Tehran was 39085 people. 379 people were selected as the sample based on the Cochran formula. The sampling method was stratified random based on the education component. The data were collected using a researcher-made questionnaire by modeling Jamili brothers, Rabiee and Mohammadian questionnaire (2011). The data were analyzed by SPSS Softwwere in two levels of descriptive and inferential statistics. 338 questionnaires were returned from 379 studied samples. The results showed that advertising of Iranian public libraries was fauiled to pass the levels of AIDA model in Tehran. But it had the effectiveness lower than average. The results show that unawwereness of community about the libraries with diverse services and easy use has led to a gap between libraries and community in general and potential users in particular. One of the essential causes of the advertising inefficiency was excessive concentration of advertising on the library itself (location). The opinions of the public libraries\u27 members in Tehran city show that unawwereness about the existence of the library and the various services that can be provided even has led to a gap among members. Therefore, Iranian public library institute in general, provincial general offices and cities secondarily, and in particular libraries themselves should use all their facilities to remove the barriers of the distance between the referees and the libraries. This problem can be solved to a large extent by extensive advertising

Competitiveness and Entrepreneurship, and their Effects on Economic Growth

Entrepreneurship is the foundation of competition and innovation among firms, as well as on the national economy. In order to create a favorable environment for entrepreneurship strengthening, it must use symmetric and appropriate competitive conditions with entrepreneurship, to improve production and employment, and thereby increase economic growth. Therefore, the main objective of this study is to investigate the effects of competitiveness and entrepreneurship, which ultimately lead to economic growth. In this paper, through collecting library resources and with a descriptive approach, the interrelations between different components of competitiveness and entrepreneurship, as well as their effects on economic growth, are discussed