Hamed Jalilian; Ahmad Soltanzadeh; Abdolhalim Rajabi; Hamidreza Heidari
Abstract
Background: This study aims to assess the consistency of the newly developed Outdoor Environmental Heat Index (OEHI) with existing environmental and physiological heat indices in low thermal stressconditions. This comparison is necessary due to potential variations in the performance of a heat stress ...
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Background: This study aims to assess the consistency of the newly developed Outdoor Environmental Heat Index (OEHI) with existing environmental and physiological heat indices in low thermal stressconditions. This comparison is necessary due to potential variations in the performance of a heat stress index when applied in conditions different from those for which it was developed.Methods: Two current and valid outdoor heat indices, including Wet Bulb Globe Temperature (WBGT) and Humidex (HD), were used in a descriptive-analytical study to compare the results obtained by OEHI and other indices in evaluating the same condition. Furthermore, the authors considered tympanic temperature as a physiological response to heat and assessed the work environment of 63 outdoor workers at three-hour intervals during the workday.Results: The highest coefficient of determination was assigned to OEHI and Humidex index (R2>0.99, P<0.0001). Regarding the correlation between the OEHI and the WBGT index, this correlation with and without considering the time of the measurement was higher than 0.98. Comparisons for the correlations of thermal indices with tympanic temperature showed poor and significant relations between thermal indices and tympanic temperature (R2<0.19, P<0.0001).Conclusion: OEHI can evaluate the thermal condition in low heat stress conditions, similar to other current and valid thermal stress indices, including WBGT and Humidex. The OEHI shows a better correlation with the Humidex than the WBGT index. However, due to the poor correlation observed between OEHI and tympanic temperature in low-stress conditions, it is recommended to use this index just as a screening index to estimate thermal environmental conditions.
Sara Kahvaei; Afshin Takdastan; Reza Jalilzadeh Yengejeh
Abstract
Background: Nowadays, the discharge of effluents containing chemicals through manufacturers or consumer industries causes major environmental problems. In this study, we assessed the effect of sludge reversal of the clarifier unit on enhancing the coagulant performance of Poly-Aluminum chloride in the ...
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Background: Nowadays, the discharge of effluents containing chemicals through manufacturers or consumer industries causes major environmental problems. In this study, we assessed the effect of sludge reversal of the clarifier unit on enhancing the coagulant performance of Poly-Aluminum chloride in the removal of turbidity/COD/PVC from PVC effluent of Bandar Imam Khomeini petrochemical plant and reduction of the amount of coagulant and costs. Methods: The experiments were carried out by Jar test with poly aluminum chloride (PAC); the returned sludge, as the assisting coagulant, and the amplitude of the differentiates including (5.5-11) pH of coagulant concentration (10-140mg/L) and concentration of returned sludge (2-20 ml) were investigated. To ensure the accuracy and precision, we repeated each stage of the experiment three times. Results: The results showed that the most optimal conditions for coagulant were at pH=8 and the optimum dose of poly aluminum chloride was 25 mg/L plus 5ml of the clear sludge volume in the clarifier. The removal efficiency of turbidity, COD, and PVC under optimum conditions of Poly-Aluminum chloride were reported 99.71%, 97.19%, and 99.55%, respectively. Conclusion: The results indicated that the sludge of the clarifier, as the main assisting coagulant, in addition to increasing the efficiency of the removal turbidity of COD and PVC reduced the dose of the main coagulant.
Ali Ojaghi; Ebrahim Fataei; Siamak Gharibi Asl; Ali Akbar Imani
Abstract
Background: The aim of this study was to provide a suitable system for disposal of hospital waste and design and construction of a safe device for infectious waste using a combination of chemical and mechanical methods.
Methods: This research is a laboratory study and based on the existing problems, ...
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Background: The aim of this study was to provide a suitable system for disposal of hospital waste and design and construction of a safe device for infectious waste using a combination of chemical and mechanical methods.
Methods: This research is a laboratory study and based on the existing problems, design and construction of a decontamination device for hospital infectious waste was performed by combination of chemical and mechanical methods in a closed reactor. To determine the appropriate mixture of different compounds of sodium hydroxide with lime and sodium carbonate with lime, three treatments were selected and used.
Results: The results of this study showed that the decontamination waste device by chemical and mechanical methods was effective in eliminating 98% of bacterial, fungal, and viral contaminants. The results showed that the neutralization rate for total bacterial contamination of the coliform, pathogenic viruses, Escherichia, Bacillus subtilis, Salmonella, and Shigella using a 30% ratio was related to the chemical composition of lime and sodium hydroxide, lime and sodium carbonate, respectively. In the designed device, the best temperature, humidity and pH conditions were determined to be 15°C, 45% and 12.8, respectively.
Conclusion: The results of the decontaminated waste tests revealed that the simultaneous application of physical and chemical methods can be used as a safe and suitable alternative in infectious waste disposal systems.
Ehsan Azizi; Alireza Arashpour; Leila Raisi Dezaki
Volume 5, Issue 3 , July 2017, , Pages 130-137
Abstract
During the last two centuries, human being has emitted huge amounts of greenhouse gases to the atmosphere, by providing energy from fossil fuels. The increasing accumulation of these gases in the atmosphere has led to "global warming" and as a result "climate change". This inauspicious phenomenon has ...
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During the last two centuries, human being has emitted huge amounts of greenhouse gases to the atmosphere, by providing energy from fossil fuels. The increasing accumulation of these gases in the atmosphere has led to "global warming" and as a result "climate change". This inauspicious phenomenon has such a wide domain that threat the survival of the human around the world. The sharp decline in fresh water sources and strategic agricultural products and severe destruction of environment are just some inevitable adverse effects of climate change. Therefore, it would be a proper ground for breaching some of the most important human rights. The aim of this research is to show effects of climate change on "right to health" and some other related rights, and therefore responsibilities of governments to fight against that. Conclusion: Climate change due to human activities, makes a proper field for breach of human rights globally, and as we see "right to health" is affected absolutely. According to principal of "common but differentiated responsibilities", most of the burdens of combating against climate change are on the shoulders of developed states and developing countries have much less obligations; but at least have common responsibilities. Rather, all of the states have clear international obligations for protecting human rights in their territories. Therefore any state must separately or together with others, take urgent and also long term measures to fight this phenomenon. If climate change continues; negligence of states in performing due diligence in this regard may lead to their international responsibility or even their incapability for governing the state in accordance with "good governance principles".
