A Riemann solver for the Drift-Flux Flow Model

Master's thesis in Petroleum engineeringIn this thesis we present a method for calculating exact solutions to a system of equations for two phase flow. This solution is valid for a special case of initial condition called the Riemann problem. The system consists of three hyperbolic conservation laws including gas mass balance, liquid mass balance and total momentum balance. Also, there is a slip relation which relates the true velocities of each phase together. In solving the Riemann problem for the two-phase flow drift flux model, some assumptions have been taken like incompressible liquid. In this thesis the development of the final solution for the Riemann problem is presented. This development includes the star region parameter determination and the exact solution in the rarefaction waves. Using the Riemann exact method to solve the equation systems of hyperbolic conservation laws helps in making a fundamental understanding of the physics and characteristic behavior. Also determining the flow parameters in the interface by the Riemann solution builds a basis for numerical approaches in two phase flow drift flux models

The Attitudes, Knowledge and Performance of Ilam Nurses Regarding Disaster Preparedness

Background: Currently, hospital preparedness is an essential element for disaster management. Accordingly, the aim of this study was to examine the attitudes, knowledge and performance of nurses with respect to crisis management. Materials and Methods: This descriptive cross-sectional study was undertaken among 112 nurses working in three hospitals affiliated to the Ilam University of Medical Sciences, Iran. A questionnaire designed according to previous studies was used to identify demographic information, nurses’ attitudes (11 questions), knowledge (6 questions), and performance (6 questions) regarding hospital preparedness during disasters. The data were analyzed using SPSS version 19.0.  Results: The overall scores for attitude, knowledge, and performance of nurses were 27.35, 9.5, and 3.88, respectively. There was a significant correlation between educational degree and nurses’ attitude (P=0.027). Also, there was a significant relationship between work experience and nurses’ attitude regarding hospital preparedness during disasters (P=0.022). Conclusion: Although most of the nurses had a fair attitude regarding hospital preparedness during disasters, their knowledge and performance were poor

Reducing passenger waiting time and energy consumption for metro timetabling: A robust optimization approach

Urban subway scheduling is a quite complicated task as any small fluctuation could disturb the entire system. Subway companies need an efficient scheduling system that best serves passengers and optimizes the utilization of resources. They need, therefore, to include real-world problems in their schedule through non-deterministic modeling. A robust optimization approach is applied in real-world data to propose an optimum train schedule that minimizes passenger waiting time and maximizes electrical energy converted from kinetic energy. Three high, normal, and low travel demand scenarios are considered to optimize train running-time duration in all three interstation movement categories, namely acceleration, coasting, and braking. To find the optimal solution, a genetic algorithm (GA) model has been applied to real data from a subway line in Tehran Metro

Preconcentration and Determination of Pantoprazole by Solid-phase Extraction Coupled with Spectrophotometry Using Iron Oxide Nanoparticles Modified with Cetyltrimethylammonium Bromide

Solid phase extraction coupled with spectrophotometric detection was applied to trace amounts of Pantoprazole (PP) drug using Cetyltrimethylammonium bromide coated-iron oxide magnetite nanoparticles CTAB@Fe3O4 MNPs. After characterization of the prepared nano-adsorbents, experimental parameters affecting the extraction efficiency of the developed method were optimized. The results obtained showed that this proposed approach is applicable in concentrations ranging from 0.1 to 1.5 μg/ml (R2 = 0.9958) indicating that follows Beer's-Lambert law. The limit of detection and the limit of quantification calculated to be 0.014 and 0.04 μg/ml, respectively. The repeatability of the proposed method was evaluated with studying intra-day and inter-day precisions described by relative standard deviations. Eventually, two samples of natural waters as well as samples of human plasma were analyzed using the proposed method. Satisfactory precision and recoveries in the complex matrices were achieved

Effect of Respiratory Rehabilitation before Open Cardiac Surgery on Respiratory Function: A Randomized Clinical Trial

Introduction: Prevention of pulmonary complications after coronary artery bypass graft is attended as a very important issue. The aim of this study was to evaluate the role of pulmonary rehabilitation before surgery for reducing the risk of pulmonary complications after surgery. Methods: In a randomized clinical trial, 60 patients undergoing heart surgery were randomly divided into two groups A and B. Chest physiotherapy was performed before and after surgery on group A patients however it was done on group B’s, only after surgery. Effects of preoperative pulmonary rehabilitation were compared between two groups, using spirometry and arterial blood gas (ABG). Results: Thirty nine males (65%) and 21 females (35%) with mean age of 8.10 ± 9.56 were analyzed.The mean differences were statistically significant for predicted forced vital capacity (FVC) (CI95%:1.3 to 8.7) and Predicted Peak Flow indices (PEF) (CI 95%: 1.9 to 9.4) of spirometry indicator,PCO2 index (of ABG parameter) (CI 95%: 1.4 to 8.9) and mean oxygen saturation (mean Spo2) (CI 95%: 0.6 to 1.7) of ABG index in two groups. Conclusion: The performance of pulmonary rehabilitation program before surgery is recommended, as it may result in the reduction of complications of heart surgery

Techno-Economic Analysis and New Design of a Photovoltaic Power Plant by a Direct Radiation Amplification System

Today, photovoltaic panels are used in various applications, and increasing their efficiency is of interest to many researchers. In this research, we try to increase the radiation density by increasing direct radiation to finally increase the energy production in photovoltaic power plants. The direct radiation amplification system is used to improve the photovoltaic efficiency. In this proposed system, energy and economics are analyzed by MATLAB software. Also, prototype testing and photovoltaic power plant testing are examined. The results show that by implementing this system in photovoltaic power plants, annual energy production can be increased. By adding this system to a photovoltaic power plant, the price of electricity produced in photovoltaic power plants will be increased from 13 ¢/kWh to 9 ¢/kWh, which shows a 31% reduction in the price of electricity per kilowatt-hour

A comprehensive systematic review and health risk assessment of potentially toxic element intakes via fish consumption in Iran

Risk assessment of heavy metals is critical in controlling and preventing risks of foodborne diseases. Fish can be used as bioindicators for exposure to potential toxic elements (PTEs), which can represent potential risks for humans. The long Iranian coastline and three major fishery regions in the country, including the northern (Caspian Sea) and southern (Persian Gulf and Gulf of Oman) seas as well as inland waters and aquacultures (rivers, dams, wetlands and fish farms) have made Iran a large producer of fish. In the first step of the present study, data collection and report of PTEs in fish from the three fishery regions (2010–2022) were carried out. In the second step, health risks were assessed using Monte Carlo simulation in child and adult consumers. The average concentrations of Cd, Hg and Pb for the northern sea, southern sea, and inland waters and aquacultures were 0.273, 0.249, 1.077; 0.430, 0.423, 1.182; and 1.387, 0.232, 1.703 μg/g per dry weight, respectively. Based on the target hazard quotient results, Hg intake of Iranian children from all the three fishery regions was more than 1, which was alarming. In the adult age group, southern sea fish consumers were at risk of Hg adverse health effects. Moreover, Cd included the highest carcinogenic risk of toxic elements in fish from the three fishery regions of Iran. Estimation of THQ, HI, ILCR and EDI revealed that consumption of fish might induce health complexities for the consumers in Iran. Moreover, Iranians from northern and southern regions of the country consumed further seafood due to the availability of high seafood sources in these regions. Hence, various indices must be used for the risk assessment of general human health. Due to the high risks of carcinogenicity/non-carcinogenicity estimated in the risk assessment, consumption of fish by infants and pregnant women must critically be assessed

Interaction between the genetic variant of rs696217‐ghrelin and food intake and obesity and dyslipidemia

In this study, we aimed to investigate the relationship between the genetic variant of rs696217-ghrelin and fasted lipid profile, indices of obesity, and environmental parameters. Amplification refractory mutation system-polymerase chain reaction (ARMs-PCR) was used for genotyping 1118 individuals recruited as part of the Mashhad Stroke and Heart Atherosclerotic Disorder (MASHAD) cohort study. The interaction between the presence of the genetic variant of rs696217-ghrelin and nutritional intake and other major determinants of obesity and lipid profile was examined in the MASHAD study population. Individuals with the TT genotype at the locus had the lowest prevalence of obesity compared to other genotypes among the individuals. No significant relationship was found between the two groups regarding the lipid profile and TT genotype. Furthermore, no significant association was found between dietary intake and the genetic variant of rs696217-ghrelin in the population under study. Individuals with a TT or GT genotype appear to be at a higher risk of obesity, compared to those with a GG genotype. The results of the current study revealed a significant association between the genetic variant of rs696217-ghrelin and obesity; however, this gene did not correlate with the risk factors of cardiovascular diseases and dyslipidemia in the Iranian population