Experimental and numerical study of an internal combustion engine coolant flow distribution

Ujednačeno hlađenje svih cilindara u motoru s unutarnjim izgaranjem predstavlja trajni izazov za mnoge inženjere i istraživače. Različiti tok i brzina strujanja rashladnog sredstva na sličnim mjestima u cilindrima može rezultirati prevelikim ili preslabim hlađenjem nekih mjesta. U ovom se radu želi dobiti motor s ujednačenijim hlađenjem. U tu su svrhu najprije riješene jednadžbe protoka 1D i 3D kako bi se dobili numerički podaci o brzini, tlaku i temperaturi na različitim mjestima postojećeg motora. Tada se primijenila metoda mjerenja brzine fotogramom čestica (Particle Image Velocimetry - PIV) kako bi se na providnom poklopcu glave cilindra izrađenom od pleksiglasa provjeravale numeričke simulacije. Nakon provjere, u svrhu postizanja odgovarajućeg hlađenja, primijenile su se neke strategije kao na primjer male modifikacije na ulazu i izlazu rashladnog sredstva u motor kao i brzine protoka sredstva, a to je rezultiralo ujednačenijim hlađenjem, dakle onemogućavanjem prevelikog ili premalog hlađenja.Uniform cooling of all cylinders in an Internal Combustion Engine has been a continual challenge of many engineers and researchers. Different flow rate and velocity of coolant at similar locations of cylinders may cause some regions to be overcooled whereas some to be undercooled. In this study more uniform cooling engine is desired. To do this, at first the governing equations of the flow were solved 1D and 3D to obtain the velocity, pressure and temperature at various points of an existing engine numerically. Then Particle Image Velocimetry (PIV) method on a transparent cylinder head made of Plexiglas was used to validate the numerical simulations. After validation, in order to reach intelligent cooling, some strategies such as small modifications in the engine coolant inlet and outlet along with its flow rates were applied that resulted in more uniform cooling which in turn prevents any over and under cooling

Personality and Credibility Evaluation: Online Health Information from the Viewpoint of Expert Users

Regarding the high importance of credibility evaluation of health information online in every day and career life, the current research aimed to explore how expert users including students and faculty members evaluate health information on the web especially with regard to their personality trait of conscientiousness. By considering the extensive body of literature and research methodologies, a random sample including 148 students and faculty members located at the two faculties of Medicine Sciences and Nursing and Midwife at the Tehran University of Medical Sciences was the population of the study. Two validated questionnaires related to credibility and conscientiousness was distributed among the participants. Gathered data were then analyzed by SPSS software. Data analysis showed that there existed some problems in evaluating the credibility of online health information and quick retrieval. About half of the participants evaluate web health information as credible often and very often. Most important quality assessment criteria were objectivity, currency, and authority. There was a significant correlation between conscientiousness and credibility assessment of the students and faculty members. There appears a change in trust to information found accord with the change in conscientiousness levels. There was no significant correlation between conscientiousness and trust to information among ill people. Quality and credibility were identified as most important problems in assessing health information on the web. There is a significant and meaningful correlation between conscientiousness and trust or mistrust to health information available via the Web

Personality and Credibility Evaluation: Online Health Information from the Viewpoint of Expert Users

Regarding the high importance of credibility evaluation of health information online in every day and career life, the current research aimed to explore how expert users including students and faculty members evaluate health information on the web especially with regard to their personality trait of conscientiousness. By considering the extensive body of literature and research methodologies, a random sample including 148 students and faculty members located at the two faculties of Medicine Sciences and Nursing and Midwife at the Tehran University of Medical Sciences was the population of the study. Two validated questionnaires related to credibility and conscientiousness was distributed among the participants. Gathered data were then analyzed by SPSS software. Data analysis showed that there existed some problems in evaluating the credibility of online health information and quick retrieval. About half of the participants evaluate web health information as credible often and very often. Most important quality assessment criteria were objectivity, currency, and authority. There was a significant correlation between conscientiousness and credibility assessment of the students and faculty members. There appears a change in trust to information found accord with the change in conscientiousness levels. There was no significant correlation between conscientiousness and trust to information among ill people. Quality and credibility were identified as most important problems in assessing health information on the web. There is a significant and meaningful correlation between conscientiousness and trust or mistrust to health information available via the Web

Patterns of physical activity and dietary habit in relation to weight status in adolescent girls

Healthy eating and physical activity habits formed during childhood can persist into adulthood and prevent or delay premature onset of a number of chronic diseases. The aim of this study was patterns of physical activity and dietary habit in relation to weight status in adolescent girls. In a cross sectional study, using two stage cluster sampling 256 adolescent girls were randomly selected from 8 Semnan secondary schools. Weigh and height were measured and Body Mass Index (BMI) was calculated. In adolescents, anthropometric indices were defined based on the CDC 2000 cut-off points for age and gender-specific BMI. Data of energy and nutrient intake was collected with the 24-hour dietary recall and food record questionnaires. The food frequency questionnaire was used to evaluate daily food consumption. Physical activity was determined using Baecke questionnaire. Data analyzed indicated that daily fat intake (p=0.003, r=+0.18), energy percent of fat (p=0.04, r=+0.01) and fast food frequency (p=0.026, r=+0.139) had significant relationship with BMI percentile. There was a significant relationship between snack frequency and weight status in high school adolescent girls (p=0.023). Data analyzed indicated that physical activity had significant relationship with weight status in adolescent girls (p= 0.0001). The findings suggest that make physical activity enjoyable and improvement food habit among adolescent girls are necessary to induct

Planning of Sustainable Development Based on Civil Rights in Torkaman Port

Undoubtedly, discussion about stability and sustainable development is meaningless without paying attention to cities and urbanization. Cities are considered as major factors of creating instability in the world. Therefore, according to inherent complexity of cities and various dimensions of their effectiveness, recognition of major and key factors for the sake of achieving to stability of cities seems necessary. The purpose of research is to acquire relatively exact description of condition of urban sustainable development from citizens’ rights point of view. This research is practical from the viewpoint of purpose and descriptive-measurable from the viewpoint of type, which has been done by scope method. Statistical society is all citizens of Torkaman city (48736) that used urban spaces which are effective on stability and instability of city. Sample volume is 381 individuals according to Cochran formula that are selected and studied accidentally. Findings of research show that civil rights identifiers with effectiveness of 0.62 and political identifiers with effectiveness of 0.18 had the most and the least effect on sustainable development of Torkaman port city

Planning of Sustainable Development Based on Civil Rights in Torkaman Port

Undoubtedly, discussion about stability and sustainable development is meaningless without paying attention to cities and urbanization. Cities are considered as major factors of creating instability in the world. Therefore, according to inherent complexity of cities and various dimensions of their effectiveness, recognition of major and key factors for the sake of achieving to stability of cities seems necessary. The purpose of research is to acquire relatively exact description of condition of urban sustainable development from citizens’ rights point of view. This research is practical from the viewpoint of purpose and descriptive-measurable from the viewpoint of type, which has been done by scope method. Statistical society is all citizens of Torkaman city (48736) that used urban spaces which are effective on stability and instability of city. Sample volume is 381 individuals according to Cochran formula that are selected and studied accidentally. Findings of research show that civil rights identifiers with effectiveness of 0.62 and political identifiers with effectiveness of 0.18 had the most and the least effect on sustainable development of Torkaman port city

Effect of methyl orange on wettability of sandstone formations: Implications for enhanced oil recovery

With the increasing global population, fossil fuel resources still represent a main contributor to the energy supply, despite the progress made in the field of renewable energies. Large quantities of residual oil from mature reservoirs cannot be produced through primary and secondary recovery methods. Among alternative recovery techniques, chemically enhanced oil recovery methods are attracting considerable interest to increase the hydrocarbon recovery from oil-bearing geological formations. The wettability of any particular formation can be used to predict the oil recovery factor of a reservoir based on its wetting state. However, due to the complex nature of geological porous media, special treatments are required to control the wetting characteristics for improving the oil recovery. In this work, methyl orange (MO), a hazardous pollutant widely discharged in industrial wastewater, was used as a chemical agent for the purpose of altering the wettability. Initially, quartz substrates were aged with 10 − 2 mol/L n-decane/stearic acid solution to mimic natural geological conditions; then, stearic acid-aged quartz substrates were treated in various concentrations of MO (10, 25, 50, 75, and 100 mg/L) for 7 days at 50 °C, followed by advancing and receding contact angle measurements at various physico-thermal geological conditions (temperature 25, 50 °C, pressure 10, 15, 20 MPa, and brine salinity 0 – 0.3 M). Our results demonstrate that increasing the temperature, pressure, and salinity of quartz aged with stearic acid has a negative effect on the wettability (resulting in a higher hydrophobicity). However, at any constant physio-thermal condition, MO significantly alters the wettability of the organic-aged quartz substrates from oil-wet to water-wet conditions, thus improving oil recovery. The concentration of MO plays a critical role, with increasing concentrations favouring the water-wet conditions. Quartz aged with MO at a concentration of 100 mg/L shows water-wet behaviour, with the lowest advancing and receding contact angles of 31 ° and 29 °, respectively, at 25 °C, 20 MPa, and 0.3 M salinity. The findings of this study provide new insights that can be useful for disposing MO in deep underground reservoirs rather than discharging into the hydrosphere, thus mitigating climate change. In addition, the present data can be helpful for improving the oil productivity from sandstone reservoirs

Thermodynamic modeling of hydrogen–water systems with gas impurity at various conditions using cubic and PC-SAFT equations of state

Hydrogen (H2) has emerged as a viable solution for energy storage of renewable sources, supplying off-seasonal demand. Hydrogen contamination due to undesired mixing with other fluids during operations is a significant problem. Water contamination is a regular occurrence; therefore, an accurate prediction of H2-water thermodynamics is crucial for the design of efficient storage and water removal processes. In thermodynamic modeling, the Peng–Robinson (PR) and Soave Redlich–Kwong (SRK) equations of state (EoSs) are widely applied. However, both EoSs fail to predict the vapor-liquid equilibrium (VLE) accurately for H2-blend mixtures with or without fine-tuning binary interaction parameters due to the polarity of the components. This work investigates the accuracy of two advanced EoSs: the Schwartzentruber and Renon modified Redlich–Kwong cubic EoS (SR-RK) and perturbed-chain statistical associating fluid theory (SAFT) in predicting VLE and solubility properties of H2 and water. The SR-RK involves the introduction of polar parameters and a volume translation term. The proposed workflow is based on optimizing the binary interaction coefficients using regression against experimental data that cover a wide range of pressure (0.34 to 101.23 MPa), temperature (273.2 to 588.7 K), and H2 mole fraction (0.0004 to 0.9670) values. A flash liberation model is developed to calculate the H2 solubility and water vaporization at different temperature and pressure conditions. The model captures the influence of H2-gas (CO2) impurity on VLE. The results agreed well with the experimental data, demonstrating the model\u27s capability of predicting the VLE of hydrogen-water mixtures for a broad range of pressures and temperatures. Optimized coefficients of binary interaction parameters for both EoSs are provided. The sensitivity analysis indicates an increase in H2 solubility with temperature and pressure and a decrease in water vaporization. Moreover, the work demonstrates the capability of SR-RK in modeling the influence of gas impurity (i.e., H2–CO2 mixture) on the H2 solubility and water vaporization, indicating a significant influence over a wide range of H2–CO2 mixtures. Increasing the CO2 ratio from 20% to 80% exhibited almost the opposite behavior of H2 solubility compared to the pure hydrogen feed solubility. Finally, the work emphasizes the critical selection of proper EoSs for calculating thermodynamic properties and the solubility of gaseous H2 and water vaporization for the efficient design of H2 storage and fuel cells

Hydrogen-wettability alteration of Indiana limestone in the presence of organic acids and nanofluid

This study focuses on the wettability alteration (changing from a hydrophobic state to a hydrophilic state) of Indiana limestone for hydrogen (H2) geological storage. We examine the effect of hexanoic acid C6, lauric acid C12, and stearic acid C18, on the wettability of Indiana limestone at ambient (298 K and 0.1 MPa) and reservoir (323 K and 8.27 MPa) conditions. The effects of silica nanofluids (silica with deionized water) at various concentrations (0.1 wt%, 0.25 wt%, and 0.5 wt%) on the wettability reversal of stearic-aged samples were tested at ambient and reservoir conditions. The results revealed increased H2-wetness (hydrophobicity) of the rock exposed to these organic acids in reservoir conditions. However, this hydrophobicity significantly decreased with the nanofluid treatment of the stearic-aged samples. This wettability reversal may increase the H2 storage capacity and containment security and lead to successful large-scale geological storage operations if H2 residual trapping is minimized