Evaluation of physico-chemical properties of biochar-based mixtures for soilless growth media

Journal of Material Cycles and Waste Management - This study was done to evaluate the suitability of biochar-based mixtures for growth media. Biochars from agricultural wastes were produced by slow...     

Saddle seat reduces musculoskeletal discomfort in microsurgery surgeons

Background. Microsurgery is a surgical procedure requiring a high degree of precision and is commonly facilitated through the use of an intraoperative microscope. When operating the microscope system, the long-term posture leads to musculoskeletal disorders in surgeons, and seats are commonly employed to diminish these problems. The present study was conducted to evaluate musculoskeletal discomfort during work with a saddle seat in comparison with conventional seats for microscopic work. Methods. Two types of seats, a saddle and a conventional one, were evaluated for 73 microsurgical surgeons in terms of musculoskeletal discomfort. Corlett and Bishop's body part discomfort scale was used to assess musculoskeletal discomfort before and after working with the seats. Results. The highest amount of discomfort that microsurgical surgeons acquire in the workplace was focused on their neck, shoulders, arms and back. During work with a saddle seat, a significant reduction was found for discomfort values in the neck, shoulder, arm, back, elbow and forearm, as well as the whole body (p?<?0.05). Conclusion. This study showed that the use of saddle seats provides a more appropriate physical posture at work, and can decrease musculoskeletal discomfort in different parts of the body of microsurgical surgeons.     

Revisiting environmental Kuznets curve: an investigation of renewable and non-renewable energy consumption role

Environmental Science and Pollution Research - Empirical studies on the environmental Kuznets curve (EKC) hypothesis have not reached a consensus on their findings because different environmental...     

Monitoring,mapping and health risk assessment of fluoride in drinking water supplies in rural areas of Maku and Poldasht,Iran

The aim of this study was to investigate and determine fluoride concentrations in drinking water supplies in rural areas of Maku and Poldasht in West Azerbaijan Province, the northwest of Iran. Fluorosis risk assessment and characterization was also investigated. Fluoride concentrations mapping was accomplished by using the GIS system. Totally, 356 water samples, including one sample in each season, were collected from 89 water supplies providing water for 95 and 61 rural areas of Maku and Poldasht, respectively. According to the results, in Maku and Poldasht, 25 and 30 rural areas had contaminated water sources, respectively. Average annual fluoride concentrations ranged from 3.04 to 7.31 mg/l in the contaminated villages of Maku, which is about 2–4.8 times higher than the maximum standard level of the Iranian drinking water standard, and 4.52–8.21 mg/l in the contaminated areas of Poldasht, which is about 3–5.47 times higher than the maximum standard level. The maximum fluoride level was determined 11.12 mg/l and 10.98 mg/l in one of villages of Maku and Poldasht Counties in summer, respectively. Neither in Maku nor in Poldasht, water resources showed dental cavity risk, while dental fluorosis risk and skeletal fluorosis risk were very significant in some villages of both cities. Children were at most risk of fluorosis. New alternative water supplies for the contaminated villages if possible, consumption of bottled water and application of reverse osmosis are recommended as remedial actions in the contaminated areas.

     

ANN-based mapping of monthly reference crop evapotranspiration by using altitude, latitude and longitude data in Fars province, Iran

The main goal of this study was to evaluate the different feed-forward back-propagation artificial neural networks’ (ANNs) potential to estimate and interpolate the reference crop evapotranspiration (ET₀) in Fars province of Iran. ET₀ was calculated using the FAO-56 Penman–Monteith method over 24 synoptic stations. Then, altitude, latitude, longitude and the month’s number as inputs and the monthly ET₀ as output (target) were used to train the ANNs. In addition, the three-layered ANNs optimized with different training algorithms including gradient descent back-propagation (gd), gradient descent with adaptive learning rate back-propagation (gda), gradient descent with momentum and adaptive learning rate back-propagation (gdx) and scaled conjugate gradient back-propagation (scg). The results indicated that scg algorithm with architecture (4 2 1) had more satisfactory results with the RMSE and R correlation coefficient equal to 18.538 mm and 0.967 in validation phase, respectively. Based on the mentioned architecture of scg algorithm, and input data form different parts of Fars province and surrounding areas, monthly ET₀ maps were produced and annual one achieved by summation of monthly maps. The maps particularly annual one showed that highest values of ET₀ could be found in the southern and especially southeastern regions, while the lowest values of ET₀ could be seen in the northern parts. Contribution of geographic and topographic variables improved the accuracy and spatial details of the resulting maps. It is interesting to note that the fundamental capability of this model is the usage of just a few parameters for ET₀ mapping. Since ET₀ is a key parameter in water demand planning, therefore, the derived maps could be useful and applicable for many purposes mainly irrigation scheduling in Fars province, Iran.     

Leaching kinetics of valuable metals from waste Li-ion batteries using neural network approach

Journal of Material Cycles and Waste Management - The kinetic study of valuable metals recovery from waste lithium-ion batteries (LIBs) using the artificial neural network (ANN) was investigated. A...     

Assessment of the living and workplace health and safety conditions of site-resident construction workers in Tehran,Iran

Objectives. The purpose of this study was to assess living and workplace safety conditions of construction workers in Tehran, Iran. Methods. This cross-sectional study was conducted among 410 construction sites in a municipal area of Tehran whose municipal building permits were issued in 2011. Data on ventilation, workplace safety and hygiene were collected by direct observation and interviews with site foremen. Noise levels were estimated from 10 sound-level-meter stations in the municipality area. Results. Lack of ventilation in the workers’ rooms was abundant. Bathrooms were unhygienic and minimum requirements such as lighting and ventilation did not exist in 80% of the cases. In nearly 50% of large construction sites, sewage and garbage disposal were inappropriate. Elevator safety was poor at all sites and no measures for fall prevention were present in over 88% of active construction sites. This study showed that the mean 24-h equivalent continuous sound level L_eq was over 70?dB in 80% of the sites during weekdays. Conclusions. The results of this study revealed poor health and safety living and working conditions of construction workers in Tehran.     

Relationship between electric spark sensitivity and activation energy of the thermal decomposition of nitramines for safety measures in industrial processes

This study presents a new simple correlation between electric spark sensitivity of nitramines and their activation energies of thermolysis, which are important for safety measures in industrial processes. The new correlation can help to elucidate the mechanism of initiation of energetic materials by electric spark. It can be used to predict the magnitude of electric spark sensitivity of new nitramines, which is difficult to measure. The methodology assumes that electric spark sensitivity of a nitramine with general formula C_aH_bN_cO_d can be expressed as a function of its activation energy of thermal decomposition as well as optimized elemental composition and the contribution of specific molecular structural parameters. The new correlation has the root mean square and the average deviations of 1.37 and 1.09 J, respectively, for 21 nitramines with different molecular structures. The proposed new method is also tested for 16 nitramines so that there is no experimental data of electrostatic sensitivity for them.