Effects of turbulent Schmidt number on CFD simulation of $$45^\circ $$ 45 ∘ inclined negatively buoyant jets

Environmental Fluid Mechanics - Employing inclined negatively buoyant jets is one of the most advantageous means to discharge brine or waste in coastal environments. However, numerical prediction...     

Estimation of soil specific surface area using some mechanical properties of soil by artificial neural networks

Soil specific surface area (SSA) is an important property of soil. Depending on the measurement techniques, determination of the SSA is costly and time consuming. Hence, a limited number of studies have been conducted to predict the SSA from the soil variables. In this study, the soil samples were taken from the literature. Fractal parameters (FP) were calculated by the model of Bird et al. (European Journal of Soil Science 51, 55–63, 2000) used as the input variables to predict the SSA. Some studies have been carried out on the prediction capability of the different parameters using the artificial neural networks (ANNs). The ANNs were further used and 20 models were developed to investigate the value of input variables to predict the SSA. The results showed that the PTF13 (RMSE?=?0.13) and PTF18 (RMSE?=?0.13) with the input variables of particle-size distribution and Atterberg limits revealed better performance than the other PTFs (in the training step). It is because of the fact that free swelling index (FSI) and Atterberg limits were closely correlated to the soil clay mineralogy as one of the important factors controlling the SSA. In general, this results demonstrated that the PTF9 with the variables of sand, clay, plastic limit (PL), liquid limit (LL), and FSI showed the best (RMSE?=?0.37) results in the estimation of the SSA. In conclusion, there was not a strong correlation between the soil mechanical properties and SSA but also ANNs were a suitable method to predict the SSA from the soil variables.     

水环境中不同形态氮对甲芬那酸光降解影响机制的研究

研究了紫外光照射下水环境中不同形态的无机氮(NO-3、NO-2和NH+4)对甲芬那酸(MEF)光解的影响.NO-3与NO-2均促进MEF的光解,NH+4对MEF的光解基本无影响;在NO-3、NO-2存在下添加适量异丙醇,显著抑制MEF的降解,实验表明NO-3、NO-2在光照下产生了·OH并参与对MEF的氧化降解.同时模拟研究了水体处于不同p E值下,水中存在的不同形态的无机氮对MEF光解的复合影响,其对MEF光解促进作用不是简单的叠加关系,增大p E值,MEF的光解速率先增大后减小.当NO-2和NH+4共存时,对MEF的光解主要表现为NO-2的影响;当NO-2和NO-3共存时,两者对MEF的光解存在拮抗作用.     

High potential for the formation of haloacetic acids in the Karoon River water in Iran

The impact of the total organic carbon (TOC), chlorine dosage, water temperature, reaction time, pH, and seasonal variation on the formation of haloacetic acids (HAAs) in the Karoon River in Iran was studied. The results showed that dichloroacetic acid and trichloroacetic acid were the most detected HAA₅. The HAA₅ formation potential (HAA₅FP) levels in the Karoon River water in spring time, when the water TOC content exceeded 4 mg/L, were 1.38 times higher than during the winter season, when the water TOC content was below 3.5 mg/L. There was not a strong correlation between the HAA₅FP and the residence time for the Karoon River water. For the range of the water temperatures studied, there was little variation in the HAA₅FP in cold water, but in warmer water, the values of the HAA₅FP varied quickly.     

Fetal lower urinary tract obstruction: What should we tell the prospective parents?

Fetal lower urinary tract obstruction (LUTO), which often results in marked perinatal morbidity and mortality, is caused by a heterogeneous group of anatomical defects that lead to blockage of the urethra. The classic prenatal presentation of LUTO includes megacystis with hydronephrosis. While mild forms of the disease can be associated with favorable outcomes, more severe disease commonly leads to dysplastic changes in the fetal kidneys, and ultimately oligohydramnios, which can result in secondary pulmonary hypoplasia and renal failure at birth. The aim of this review is to provide practitioners with a general overview of the diagnosis and treatment of LUTO based on disease severity, along with some points to consider when counseling prospective parents of fetuses with this condition.     

Seasonal trend and source identification of polycyclic aromatic hydrocarbons associated with fine particulate matters (PM2.5) in Isfahan City,Iran, using diagnostic ratio and PMF model

Environmental Science and Pollution Research - Particulate matters (PMs) and their associated chemical compounds such as polycyclic aromatic hydrocarbons (PAHs) are important factors to evaluate...     

An observational study of child safety seat use in an international safe community: Tehran,Iran

Objective: Despite strong evidence of the effectiveness of child safety seats in reducing injuries, the use of these devices in some communities is still rare. The purpose of this study was to determine the prevalence of child safety seat use and the factors influencing its use in the safe community of Tehran.

Methods: This roadside observational study was conducted in 2015 and 2,178 personal cars with a child under 12 years aboard were observed on Tehran's streets in regard to use of child safety seats. Other variables such as the gender of the driver, driver's age group, type of street, region of municipality, time of day, and day of the week were also collected.

Results: Prevalence of child safety seat use was 4.3% and was significantly higher among women drivers, on freeways, and in municipal regions 1, 4, and 7.

Conclusions: The prevalence of child safety seat use in Tehran as a most populous member of the international safe community was very low and most children commuted in insecure situations in the vehicle. Therefore, it is proposed that plans should be made to increase the use of child safety seats in international safe communities.     

Game analysis of Chinese stakeholders in collective forest rights system reform

In the current stage of Chinese forest ownership reform, the central and local governments as well as the forest farmers play different roles with variations in their expected returns. Managing these respective relationships between the forestry stakeholders to maximize their benefits while actively engaging each stakeholder in the collective forest ownership reform process has become an important issue. This study uses the game theory methodology to analyze the relationship between the different reform stakeholders and then builds on the forest farmers’ participation in the reform model process at the reform movement micro-level. This model calculates the forest products equilibrium marketing sales and the government subsidies provided to the forest farmers, when the forest farmers willingly participate in the reform process. It will provide a reliable basis for formulation of government policies which positively impacts Chinese forestry reform.