APPLICATION OF IMAGE PROCESSING AND FINITE ELEMENT ANALYSIS IN MODELING CHLORIDE DIFFUSION IN CONCRETE

Utilizing numerical simulation models to predict the long-term mechanical and transport behavior of concrete structures is becoming increasingly popular. The majority of these models have been developed using laboratory test data that consider concrete as a homogeneous material with spherical aggregates. These models could not be a represented of real concrete because it has no primitive shaped aggregate besides that the porosity size and distribution varies from point to point. In this study a novel method for more accurate prediction of the chloride diffusion in concrete was developed. A general framework of the quantitative computed tomography (QCT) and finite element analysis was used to construct 3D images of concrete cylinders. A computer code was developed using Matlab to analyze images and to measure the amount and distribution of coarse aggregates and voids in the concrete cylinders. The rapid performance and independency from personnel, as well as the capability of inspecting the internal structure and possible damages within the cylinders, make this method very applicable for quality control and quality assurance applications as well as for forensic investigations. During this study, it was realized that the shape and distribution of aggregates as well as Interfacial Transition Zones (ITZs) have significant impact on the chloride diffusion into the concrete. Therefore, it was imperative to construct a predictive model which was closer to reality, considering the distribution of aggregate particles (coarse and fine), voids, and ITZs (around both coarse and fine aggregates). Thus, a numerical method for the prediction of the chloride penetration into concrete was developed using a scanned copy of the concrete internal structure. The results obtained from this study showed that, QCT along with image analysis techniques used to study the air void content and distribution as well as coarse aggregate content in concrete in 3D had a good agreement with the microscopic analysis. The major advantage of QCT technique is much short time required for analysis with the QCT method compared to that with the conventional microscopic studies. The result from the chloride diffusion in concrete showed that chloride concentration gradient when ITZ is considered around aggregates is much higher compared to that in concrete without considering the ITZ. The positions and shapes of the coarse aggregates can also affect the diffusion process and the chloride ion diffusivity. The experimental and simulation results indicated that closer aggregates to the steel bar can increase the rate of the chloride diffusion as well as the rate of corrosion

Finite Element Modeling of Concrete Based on Quantitative Computed Tomography (QCT)

Models have been used before to predict the mechanical and transport behavior of concrete. In most of these studies, aggregates were considered either circle or sphere and the impact of the aggregates geometry and in-homogeneities in concrete structure is ignored. The objective of this study is to develop a novel method for accurate prediction of the mechanical behavior of concrete using quantitative computed tomography (QCT)-based finite element analysis. Concrete cylinders were cast and cured for 28 days. The QCT scans were carried out on the samples using a clinical CT scanner. An image processing method was applied to detect aggregates, paste content and the air voids. The distribution of each phase then calculated in each image slice (2D) and in the bulk material (3D). The processed QCT images were directly converted into voxel-based 3D FE models for linear and nonlinear analyses. The FE models were generated by conversion of each voxel into an 8-noded brick element. Air void content of the cylinders (2D and 3D) was determined. In addition, the aggregates content was estimated using the image analysis. In both cases, the results obtained by the image analysis and the actual measurement and ASTM method are in very good agreement

Development of sustainable energy indexes by the utilization of new indicators: A comparative study

Decision making to improve energy sustainability requires scientifically information based on sustainability. Since there are different sustainability targets and specific decision problems in this regard, hence to achieve these targets or solve these problems, relevant sustainability indicators are needed. In this study, is investigated and developed a variety of applicable indicators to enhance sustainable energy development index. Indeed, the main aim of this study is to present new effective indicators related to sustainable development goals, investigating the most important challenges related to energy sustainability. Additionally, this work is following to find the main gaps which are as obstacles in achieving energy sustainability for 12 different countries. To do this, firstly the required data from international energy agency (IEA) and world bank gathered and then is analyzed.Postprint (author's final draft

Energy sustainability analysis based on SDGs for developing countries

Electrical production for residential areas is one of the most important goals of SDGs (17 UN goal) and UN-Habitat III (14 goals) that can be achieved by renewable energy. Now, renewable energy is a significant issue that must be considered seriously as a policy and in order to achieve energy sustainability on a global scale especially in whole developing countries. Also, since the role of renewable energy in sustainable development is remarkable, thus this article presents a comprehensive discussion of energy sustainability for urban areas with related energy indicators and technical analysis of a Hybrid Power System to show the importance of renewable energy to gain energy sustainability. This paper presents the feasibility of using PV-DG hybrid systems as the reliable energy by an economic and technical analysis in one of the southern cities of Iran use of HOMER software. Regarding the high average of solar radiation that is about 5.4 kWh/m2/d in Chabahar city, technical analysis of this system demonstrates that this city has a high capacity to producing the electrical energy via PV-diesel hybrid system with total electrical production amount of 10,575 kWh/yr from PV (8,447 kWh/yr) and Diesel system (2,128 kWh/yr). For do this work at the first, the required data is gathered from the meteorological organization of Iran and then technical and economic analysis is conducted with the Homer software. This study regarding the high potential of solar energy of Chabahar city shows that to achieve development especially in the energy sustainability field needs to implementing proper actions such as enough investment on clean energy and using renewable energy for electrical production.Postprint (author's final draft

MODELLING THE CONSTRUCT OF BURNOUT PREVENTION: THE CASE OF SUPERVISORS’ PERCEPTIONS

La sobrecarga de trabajo de los docentes puede ocasionar desafíos para los docentes que provoquen agotamiento a largo plazo si no se abordan. En consecuencia, el presente estudio tiene como objetivo examinar las fuentes de prevención del agotamiento desde las perspectivas de los supervisores EFL (inglés como lengua extranjera). Los participantes fueron 85 supervisores de EFL iraníes cuyo trabajo consistía en observar y dar retroalimentación a los maestros sobre su desempeño docente en varios niveles de dominio del idioma, desde los niveles de primaria hasta los avanzados. En este estudio se empleó un diseño secuencial de método mixto. Primero, la recopilación de datos cualitativos se realizó mediante entrevistas con 30 participantes para determinar las fuentes de prevención del agotamiento desde la perspectiva de los supervisores. A continuación, se diseñó un cuestionario de prevención de agotamiento utilizando los resultados de las entrevistas, después de lo cual se administró a los participantes restantes. Los datos recopilados fueron analizados por factores para identificar los componentes de la construcción de prevención de agotamiento. Los resultados del análisis de contenido de los datos de la entrevista indicaron que el apoyo de los maestros por parte de sus colegas, la situación menos estresante y la satisfacción laboral fueron las principales fuentes de prevención del agotamiento. El análisis factorial mostró las mismas fuentes de agotamiento que los componentes principales de la construcción de prevención de agotamiento. Los hallazgos de este estudio enfatizan la contribución del apoyo educativo y emocional de los maestros, proporcionando un lugar de trabajo constructivo y saludable, así como ingresos deseables como formas de prevención del agotamiento en los maestros de EFL.A sobrecarga de trabalho do professor pode causar desafios para os professores, levando a esgotamento a longo prazo, se não forem abordados. Consequentemente, o presente estudo tem como objetivo examinar as fontes de prevenção de burnout das perspectivas dos supervisores de EFL (inglês como língua estrangeira). Os participantes foram 85 supervisores iranianos de EFL, cujo trabalho era observar e dar feedback aos professores sobre seu desempenho no ensino em vários níveis de proficiência linguística, do nível básico ao avançado. Um projeto de método misto seqüencial foi empregado neste estudo. Primeiro, a coleta de dados qualitativos foi realizada por meio de entrevistas com 30 participantes, a fim de determinar as fontes de prevenção de burnout na perspectiva dos supervisores. A seguir, foi elaborado um questionário de prevenção de burnout, utilizando os resultados das entrevistas, após o qual foi aplicado aos demais participantes. Os dados coletados foram analisados por fatores para identificar os componentes do construto de prevenção de burnout. Os resultados da análise de conteúdo dos dados da entrevista indicaram que o apoio dos professores de seus colegas, a situação menos estressante e a satisfação no trabalho foram as principais fontes de prevenção de burnout. A análise fatorial mostrou as mesmas fontes de burnout que os principais componentes do construto de prevenção de burnout. As conclusões deste estudo enfatizam a contribuição do apoio educacional e emocional dos professores, proporcionando um local de trabalho construtivo e saudável, bem como a renda desejável como formas de prevenção do esgotamento nos professores de EFL.Teacher work overload can cause challenges for teachers leading to burnout in the long term if not addressed. Consequently, the present study aims at examining the sources of burnout prevention from EFL (English as a foreign Language) supervisors’ perspectives. The participants were 85 Iranian EFL supervisors whose job was observing and giving feedback to teachers about their teaching performance at various levels of language proficiencies from elementary to advanced levels. A sequential mixed method design was employed in this study. First, collection of qualitative data was performed using interviews with 30 participants in order to determine the sources of burnout prevention from supervisors’ perspectives. Next, a burnout prevention questionnaire was designed using the results of the interviews, after which it was administered to the remaining participants. The collected data were factor analyzed to identify the components of burnout prevention construct. Results of content analysis of the interview data indicated that teachers’ support from their colleagues, less stressful situation, and job satisfaction were the main sources of burnout prevention. Factor analysis showed the same sources of burnout as the main components of the burnout prevention construct. The findings of this study emphasize on the contribution of teachers’ educational and emotional support, providing constructive and healthy working place, as well as desirable income as ways for prevention of burnout in EFL teachers

Effect of Early Post Cesarean Feeding on Gastrointestinal Complications

Background: Gastrointestinal complications are the main complication in patients after cesarean section. Previous studies have reported different results about the effect of early post cesarean feeding on vomiting, nausea, flatulence and illus. Objectives: To identify the effect of early post cesarean feeding on gastrointestinal complications. Materials and Methods: This randomized controlled trial was conducted on 82 women who underwent cesarean section in Mashhad Omolbanin hospital. They were randomly assigned to two equal experimental and control groups. The experimental group started oral fluids four hours after surgery, followed by a regular diet after bowel sounds returned. Mothers in the control group received fluid intravenously during the initial 12 hours, and then if bowel sounds were heard, they were permitted to receive oral fluids and they could start a solid diet if they had defecation. Vomiting and flatulence were assessed with a visual analog scale. Nausea was assessed with an observation questionnaire and illus was assessed via bowel sounds, gas passing and defecation 4, 12, 24, 36 and 48, hours post surgery in the two groups. Also, they were studied for the time of gas passing, bowel sound return, defecation, sitting, walking and breast-feeding. Data were analyzed using the chi-square, Fisher's exact test, t-test and Man-Whitney U test. Results: No mother experienced nausea, vomiting and illus. Flatulence severity 4 and 12 hours after surgery was similar in both groups (P = 0.856, P = 0.392). However, flatulence severity 24, 36 and 48 hours after surgery, was less in the experimental group (P = 0.030, P = 0.016, P = 0.001). Also, bowel sound return, time of gas passing, defecation, sitting and walking were less in the experimental group (P = 0.001). Conclusion: This study showed that early feeding decreased post cesarean gastrointestinal complications

Pathological study of parasitism in racing pigeons: An indication of its effects on community health

Several non-official reports from different clinics, governmental veterinary head-quarters and bird keepers indicate that most of the young pigeons die with suspicious infection to parasites. In addition, the pigeon owners were complaining of skin itching on their head. Thus, this research was conducted to determine the pathological study of parasitism in racing pigeons with an indication of its effects on community health. It was carried out from May to September 2011, by an experimental study on 250 (168 adults and 82 nestlings) blood and faecal samples (Soulsby, 1982) randomly collected from suspected pigeons (mostly young) and 25 specific free pathogen birds as control. Tissue samples of both infected and control birds were removed and compared with samples of the histological study. Moreover, 12 hair samples taken from pigeon owners were checked for external parasites. The data indicate prevalence rate of various helminthes including Raillietina achinobothridia (10.4%), Syngamus trachea (8.4%), Capillaria colombae (6%) and Ascaridia colombae (8.4%). The results reveal some porotozan infections including Haemoproteus colombae (20.8%), Trichomonas gallinae (26.8%) Cryptosporidium sp. (1.2%) and Eimeria sp. (21.6%) and also ectoparasites including Lipeurus sp. (3.2%), Menopen gallinae (15.2%), Ceratophyllus colombae (10.4%) and Louse fly (12%). Multiple infections observed with internal parasites were 19/4%. However, co-infection of internal and external parasites was 24.4%. Meanwhile, five out of the 12 hair samples taken from pigeon owners were infected with the fleas (C. colombae) and lice (M. gallinae) as seen by the clinical manifestation of allergic urticarial reaction and itching. Histological studies showed a visible vascular congestion and a massive lymphoplasmacytic infiltration inside the smooth muscular layer of the small intestine of infected pigeons. This result indicates that pigeons and their owners may be at high risk of single or multiple parasitic infections.Key words: Endoparasite, ectoparasites, ovum, birds, fleas, epidemiology

Fuel saving due to pinch analysis and heat recovery in a petrochemical company

Nowadays, decreasing the amount of natural resources and increasing the price of it, motivates to consider energy conservation as a main concern of many process industries, especially oil, refinery and petrochemical plants. Pinch Analysis (PA) is a powerful method for identifying and selecting technical solution to improve efficiencies and provide an optimum procedure for energy saving. This paper analyses, the effectiveness of applying PA to optimize energy consumption for a given set of process streams in a Petrochemical Company in Iran. In this study, firstly, the interested process streams have been selected, maximum heating and cooling load are computed, and then composite curves have been drawn - by Matlab code - which provides a visual profile of the availability of heating or cooling from the process streams. Secondly, the cost of recovered heat is computed in terms of fuel saving, which confirms applying PA could save significant amount of fuel expenses for the company. Finally, the corresponded Heat Exchanger Network (HEN) has been designed, and the investment costs for heat exchangers have been computed in order to find out payback time of the investment costs which is approximately 17 months for this case study