Barriers and Strategies of Fruit and Vegetable Consumption in High School Students in Sanandaj

Background and Objective: Adolescence is one of the most important periods of life, in which the lifestyle is formed and established. On the other hand, the use of appropriate amounts of fruits and vegetables in daily diet is one of the important strategies for preventing illness and promoting health, especially during adolescence. This study was conducted with the aim of investigating barriers and strategies of fruit and vegetable consumption in high school students. Participants and Methods: This qualitative study was conducted, using a semi-structured questionnaire in a focused group discussion among high school students (male and female) in Snandaj in 2017. The participants included 20 females and 16 males, who participated in 4 group discussions in the high schools. All group discussions were recorded, analyzed, and categorized immediately after completion. Due to the similarity of the propositions extracted from the group discussions with the Pen-3 pattern, this model was used for analysis. Results: The concepts extracted based on the model were categorized in six sections including positive and negative perceptions, positive and negative enablers, and positive and negative amplifiers. Some of the findings of the present study were low nutritional knowledge, beliefs and values, the impact of peers, the role of parents, the media, and access. Conclusion: Adolescent barriers to the consumption of fruits and vegetables are not merely dependent on the person themselves and are influenced by external factors. Therefore, in designing interventions to improve the consumption of fruits and vegetables, all effective factors should be addressed

Investigation of Oxy-Fuel Combustion through Reactor Network and Residence Time Data

Oxy-fuel combustion is a promising strategy to minimize the environmental impact of combustion-based energy conversion. Simple and flexible tools are required to facilitate the successful integration of such strategies at the industrial level. This study couples measured residence time distribution with chemical reactor network analysis in a close-to-reality combustor. This provides detailed knowledge about the various mixing and reactive characteristics arising from the use of the two different oxidizing streams

Mapping 123 million neonatal, infant and child deaths between 2000 and 2017

Since 2000, many countries have achieved considerable success in improving child survival, but localized progress remains unclear. To inform efforts towards United Nations Sustainable Development Goal 3.2—to end preventable child deaths by 2030—we need consistently estimated data at the subnational level regarding child mortality rates and trends. Here we quantified, for the period 2000–2017, the subnational variation in mortality rates and number of deaths of neonates, infants and children under 5 years of age within 99 low- and middle-income countries using a geostatistical survival model. We estimated that 32% of children under 5 in these countries lived in districts that had attained rates of 25 or fewer child deaths per 1,000 live births by 2017, and that 58% of child deaths between 2000 and 2017 in these countries could have been averted in the absence of geographical inequality. This study enables the identification of high-mortality clusters, patterns of progress and geographical inequalities to inform appropriate investments and implementations that will help to improve the health of all populations

A detailed kinetic mechanism for combustion of natural gas in innovative, unconventional conditions

Forecasting the global energy demand is remarkably important for future energy policy and security. Considering various scenarios for world energy production and demand, the role of natural gas in shaping future energy demand will be notable, derived by its environmental advantages and versatility relative to other combustible fuels. This work is in the context of Combustion for Low Emission Application of Natural Gas project (CLEAN-Gas) funded by European Union's Horizon 2020 research and innovation programme under Marie Sklodowska-Curie Innovative Training Network (ITN), aiming to propose an innovative approach to improve natural gas combustion in industrial processes including detailed chemistry and computational fluid dynamics. Towards the goal, this work aims to extend the knowledge on hidden aspects of natural gas in the low environmental impacts combustion technologies through the development of comprehensive, detailed kinetic mechanism with predictive capabilities in a wide range of operating conditions of interest for real systems. The kinetic mechanism of natural gas (C1-C3 fuels) describing the oxidation and combustion of natural gas is conceived and developed in a modular and hierarchical approach. This thesis is an effort to fill the pressing need of a reliable and widely validated kinetic mechanism, specially developed for modern combustion systems with near-zero emission. More than 200 different experiments containing more than 6000 data points of various apparatuses such as plug flow reactor (PFR), Jet stirred reactor (JSR), shock tube, and 1-D laminar flame are collected from literature for the sake of extensive and critical model comparisons. This database is the most extensive set of experimental data available, which is beneficial for understanding the complex combustion processes of modern combustion technologies that have been hindered from successful integration into the industry. A systematic study is performed on the combustion characteristics, less-known aspects and critical reaction pathways involved in MILD and oxy-fuel combustions. Diluent effects are evaluated in detail, and it is noteworthy to highlight that physical and chemical effects of diluent on the reactivity, laminar flame speed, ignition delay time, and formation of products are strongly dependent on the operating conditions (temperature, pressure, and equivalence ratio). Therefore, the analysis of the dilution effects is very case sensitive, and the contribution of each characteristic may vary accordingly. Both H2O and CO2 dilution reduces the system reactivity. The effect of H2O is more notable due to chemical effects related to enhanced collisional efficiencies at the operating conditions of JSR experiments. On the contrary, CO2 has a higher impact on inhibiting flame propagation at higher temperatures, mainly due to the thermal and radical scavenging effects. Moreover, the effect of CO2 addition on methane ignition delay times is very marginal. The most likely explanation is that CO2 is scarcely reactive during the ignition, because of its stability, and does not actively modify the pool of radicals. Finally, despite the satisfactory model prediction and reasonable agreement shown, the underlying impact of rate parameters uncertainty on model prediction is still not negligible. It has been shown that even if the kinetic mechanism is complete and free of any missing reaction pathway, rate coefficient uncertainties generally precludes the possibility of predicting relevant combustion properties in some peculiar conditions. One of the primary reasons has been the lack of general agreement as to how to move forward in obtaining a comprehensive, unified and predictive model for fuels combustion.Doctorat en Sciences de l'ingénieur et technologieinfo:eu-repo/semantics/nonPublishe

Impacts of inner/outer reactor heat recirculation on the characteristic of micro-scale combustion system

Flame stability and thermal performance of two different heat recirculation micro-combustors (inner reactor heat recirculation (IHR) and outer reactor heat recirculation (OHR)) are investigated using computational fluid dynamics (CFD) and compared together. A two-dimensional steady state CFD model including temperature dependent properties, laminar flow and transport, one step chemical reaction, surface-to-surface radiation, and heat conduction within solid walls has been carried out to assess flame propagation velocity, flame thickness, excess enthalpy, heat loss, and emitter efficiency. It is observed that both cases significantly extend flammability and blow-off limits due to preheating of the reactive mixture. The maximum flame propagation velocities of IHR and OHR in stoichiometric mixture are predicted 160.2 cm/s and 126.1 cm/s, respectively. It is found that super-adiabatic flame temperature takes place when dimensionless excess enthalpy is positive and it is maximum in the stoichiometric equivalence ratio. Heat loss can be varied from 245.8 to 248.6 W for IHR and from 249.6 to 254 W for OHR configuration. Therefore, there is a relative improvement in the Thermal quenching limit of IHR. It is concluded that IHR micro-combustor profoundly affects flame characteristic and stability, but OHR presents a higher range of emitter efficiency. © 2015 Elsevier Ltd. Abstrac

Urease activity and microbial biomass of carbon in hydrocarbon contaminated soils. A case study of cheshmeh-khosh oil field, Iran

Crude oil contamination in soils may result in destructive effects on soil microorganisms and plants and act as a source of groundwater contamination. The objective of this study was to evaluate the biological activities for a better understanding of ecological risks. A couple of biological assays, including soil microbial biomass of carbon (SMBC) and urease activity (UA), were used to evaluate the microbial activities in soils. The chemical analysis demonstrated different values of total petroleum hydrocarbons (TPHs) concentrations (from 0.12 to 2.99 mg/kg of dry soil) and relatively high quantities of Nickel (from 32 to 136.8 mg/kg of dry soil) and cadmium (from 0 to 4 mg/kg of dry soil) in samples. UA and SMBC values were comparatively lower in close distances to oil wells, pipelines, and especially drilling sediments pool. The spatial variability maps using the interpolation module by GIS specified the line from northwest to the southeast of the area as a more affected area by TPHs and Ni + Cd.SCOPUS: ar.jDecretOANoAutActifinfo:eu-repo/semantics/publishe

Effects of bluff body shape on the flame stability in premixed micro-combustion of hydrogen-air mixture

Combustion characteristics and flame stability of lean premixed hydrogen-air mixture in a micro-combustor with different shapes of bluff body (circle, ellipse, diamond, semicircular, half ellipse, triangle, crescent, arrowhead and wall-blade) under various physical and chemical circumstances were investigated by solving two-dimensional governing equations. The blow-off limit of different bluff bodies, combustion efficiency, wall temperature and exhaust gas temperature of micro-combustor were examined. The results illustrate that in moderate equivalence ratio (ø = 0.5) and low velocity (V = 10 m/s), the maximum flame temperature occurs when a wall-blade is applied as a bluff body. When the inlet mixture velocity increases from V1 = 10 m/s to V 2 = 20 m/s, the flame temperature of the micro-combustion rises in all cases. Apart from the wall-blade, the maximum flame temperature was recorded at V2 = 20 m/s for all cases and when the inlet velocity of the mixture increased from 20 m/s to 30 m/s, the flame temperature reduced in all studied cases. Therefore, the flame of micro-combustor with wall-blade bluff body is more stable than other cases. Moreover, the mean wall temperature of the micro-combustor with wall-blade bluff body is highest. Emitter efficiency is very high in the micro-combustor with wall-blade bluff body in lower velocities. © 2014 Elsevier Ltd. All rights reserved

Numerical investigation of biogas flameless combustion

The purpose of this investigation is to analyze combustion characteristics of biogas flameless mode based on clean technology development strategies. A three dimensional (3D) computational fluid dynamic (CFD) study has been performed to illustrate various priorities of biogas flameless combustion compared to the conventional mode. The effects of preheated temperature and wall temperature, reaction zone and pollutant formation are observed and the impacts of combustion and turbulence models on numerical results are discussed. Although preheated conventional combustion could be effective in terms of fuel consumption reduction, NOx formation increases. It has been found that biogas is not eligible to be applied in furnace heat up due to its low calorific value (LCV) and it is necessary to utilize a high calorific value fuel to preheat the furnace. The required enthalpy for biogas auto-ignition temperature is supplied by enthalpy of preheated oxidizer. In biogas flameless combustion, the mean temperature of the furnace is lower than traditional combustion throughout the chamber. Compared to the biogas flameless combustion with uniform temperature, very high and fluctuated temperatures are recorded in conventional combustion. Since high entropy generation intensifies irreversibility, exergy loss is higher in biogas conventional combustion compared to the biogas flameless regime. Entropy generation minimization in flameless mode is attributed to the uniform temperature inside the chamber. © 2014 Elsevier Ltd. All rights reserved