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

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

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

Numerical modelling and techno-economic assessment of a vacuum swing adsorption process for Post-combustion CO2 capture

LAUREA MAGISTRALEI sistemi a base di solventi sono attualmente la tecnologia di riferimento per la cattura di CO2 post-combustione. Tuttavia, a causa dell'elevata penalizzazione energetica che impongono all'impianto ospite, negli ultimi anni altre alternative come l'adsorbimento oscillante sottovuoto (VSA) stanno attirando l'attenzione non solo per la minore penalizzazione energetica ma anche per il solo utilizzo di energia elettrica invece dell'energia termica che evita le complessità di integrazione del calore alla pianta ospite. Il transitorio inerente alle fasi del processo del sistema basato su assorbente ci evita di utilizzare il software di simulazione del processo commercializzato per la modellazione del processo. In questo lavoro, abbiamo risolto numericamente le equazioni del modello in modalità transitoria utilizzando MATLAB finalizzato al raggiungimento del Cyclic Steady State (CSS) in cui vengono valutate le prestazioni del sistema. Il modello viene quindi validato utilizzando i dati di una delle principali pubblicazioni pionieristiche in questo campo. Per valutare le prestazioni del sistema su larga scala, vengono utilizzati i dati sui fumi di un impianto WtE da 200 MWth. Si suggerisce inoltre una metodologia di pianificazione del ciclo e dimensionamento delle colonne per fornire un'alimentazione continua al sistema VSA riducendo al minimo l'ingombro dello schema in scala. Per raggiungere lo stato finale di purezza del 95% e 110 bar, che è il requisito minimo di un sistema CCUS standard, il flusso in uscita del VSA viene ulteriormente trattato in CO2 Purification Unit (CPU). Vengono confrontati tre diversi scenari in termini di performance tecniche ed economiche a diversi livelli di ripresa. Lo scenario di recupero più elevato, con un recupero complessivo del 91%, ha comportato un consumo di energia elettrica di 397 kWh/(tCO2 purificata) per il sistema integrato VSA-CPU. Inoltre, il costo totale di 108,5 €/(tCO2 purificata) è calcolato sulla base del prezzo dell'elettricità nel 2022, che può essere ridotto del 20% se il prezzo dell'elettricità torna al livello del 2020.Solvent-based systems are currently the benchmark technology for post-combustion CO2 capture. However, due to the high energy penalty that they impose on the host plant, other alternatives such as the Vacuum-Swing Adsorption (VSA) are raising attention in recent years not only because of the lower energy penalty but also of the sole use of electricity instead of thermal energy which avoids the heat integration complexities to the host plant. The transient inherent of sorbent-based system’s process steps avoids us to use the commercialized process simulation software for process modelling. In this work, we numerically solved the model equations in transient mode using MATLAB aimed at reaching the Cyclic Steady State (CSS) in which the performance of the system is evaluated. The model is then validated using the data from one of the main pioneer literature in this field. To assess the performance of the system on a large scale, the flue gas data from a 200 MWth WtE plant is used. A cycle scheduling and column sizing methodology is also suggested for supplying a continuous feed to the VSA system while minimizing the footprint of the scaled-up scheme. To reach the final state of 95% purity and 110 bar which is the minimum requirement of a standard CCUS system, the exited stream of the VSA is further treated in a CO2 Purification Unit (CPU). Three different scenarios are compared in terms of technical and economic performances at different recovery levels. The highest recovery scenario with an overall recovery of 91%, resulted in 397 kWh/(tCO2 purified) of electrical energy consumption for the integrated VSA-CPU system. Moreover, the total cost of 108.5 €/(tCO2 purified) is calculated based on the electricity price in 2022, which can be decreased by 20% if the price of electricity will set back to its 2020’s level

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

Angular sensitivity of blowfly photoreceptors: intracellular measurements and wave-optical predictions

The angular sensitivity of blowfly photoreceptors was measured in detail at wavelengths λ = 355, 494 and 588 nm. The measured curves often showed numerous sidebands, indicating the importance of diffraction by the facet lens. The shape of the angular sensitivity profile is dependent on wavelength. The main peak of the angular sensitivities at the shorter wavelengths was flattened. This phenomenon as well as the overall shape of the main peak can be quantitatively described by a wave-optical theory using realistic values for the optical parameters of the lens-photoreceptor system. At a constant response level of 6 mV (almost dark adapted), the visual acuity of the peripheral cells R1-6 is at longer wavelengths mainly diffraction limited, while at shorter wavelengths the visual acuity is limited by the waveguide properties of the rhabdomere. Closure of the pupil narrows the angular sensitivity profile at the shorter wavelengths. This effect can be fully described by assuming that the intracellular pupil progressively absorbs light from the higher order modes. In light-adapted cells R1-6 the visual acuity is mainly diffraction limited at all wavelengths.

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

IRANIAN EFL TEACHERS’ PERCEPTIONS OF BURNOUT CAUSES AND SOURCES OF PREVENTION

The objective of this study was to examine the Iranian language teachers’ perceptions of burnout causes and sources of prevention. Participants of the study consisted of 76 male and female language teachers with 2-10 years of teaching experience in Tehran. Selection of the participants was performed according to convenience sampling form a famous language school in Tehran. A sequential mixed approach was used, in which 20 teachers participated in interviews and the remaining participants completed the burnout prevention survey that was designed based on the qualitative data collected from the interviews. Then the burnout prevention questionnaire was developed using the results of the interviews and administered to the remaining participants. In the next step, analysis of the collected data was performed through factor analysis to identify the components of burnout prevention. According to the results of the content analysis of the interview data, Iranian EFL teachers viewed work and life balance, organized working conditions, healthy classroom context and vital as well as growing working environment as the sources which could prevent burnout. Based on the results of factor analysis, work and life balance and vital as well as growing working conditions constituted one component of the burnout prevention, organized working environment made up the next component, and healthy classroom environment comprised the last component of the burnout prevention