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Showing 7 results for Ultraviolet
Evaluation of the Relationship Between Global Ultraviolet Indea in Different Regions of Iran with Skin Cancer in 1383
R Nabizadeh, Sh Salehi, M Younesian, K Naddafi,
Volume 2, Issue 4 (3-2010)
Abstract

Backgrounds and Objectives:Skin cancer is the most frequent malignancy in Iran. Exposure to the excessive ultraviolet radiation is an important factor in creating skin tumors. The purpose of this study is to determine how the ultraviolet index has been distributed in all townships throughout the country, to determine different kinds of skin cancer and to evaluate a geographical distribution of skin cancers with regard to the UV geographical distribution.
Materials and Methods: This study is ecologic, descriptive and analytical in nature. A total number of 6921 skin cancer cases registered at the Center for Disease Control of Iran in 2004 were thoroughly analyzed and UV data were collected from the world wide web. With the help of ArcGIS software and SPSS, the statistical analysis was done.
Results:The incidence rates were 10.13 for the total skin cancer, 7.53 for basal cell carcinoma, 1.79 for squamous cell carcinoma and 0.39 for malignant melanoma per 100000 population of Iran. The mean ultraviolet index differed from 9 in July to 3 in January. The correlation between the skin cancer incidence at the level of districts and ultraviolet index was not significantly observed.
Conclusion:Skin cancer is a public health problem in Iran. Further research in this regard would lead to skin cancer registration improvement and more understanding of different climatic, cultural and behavioral factors in developing skin tumors. With this knowledge the possibility of more effective prevention of the most prevalent cancer in Iran can be created.


Investigating the Efficiency of Ultraviolet Irradiation for Inactivation of Free Living Nematodes in Water
M.h Dehghani, A Zarei, A.h Mahvi, Gh.r Jahed Khaniki, E.b Kia,
Volume 4, Issue 4 (3-2012)
Abstract

Background and Objectives: Free living nematodes due to their active movement and resistance to chlorination don't remove in conventional water treatment processes thus can be entered to distribution systems and cause adverse health effects. UV irradiation can be used as a method of inactivating these organisms.
Materials and Methods: This study is done to investigate the effect of ultraviolet lamp on inactivation of free living nematode (Rhabitidae) in water. The effects of duration of irradiation, turbidity, temperature, UV dose and pH are investigated in this study. Ultraviolet lamp used in this study was a 11 watt lamp with intensity of 24 µw / cm2.
Results: Contact time required to achieve 100% efficiency for larvae nematodes and adults were 9 and 10 minutes, respectively. Increase of turbidity up to 25 NTU decreased inactivation efficiency of larvae and adult nematodes from 100% to 66% and 100% to 64%, respectively. Change in pH ranged from 6 to 9 did not affect the efficiency of inactivation. With increasing temperature inactivation rate increased.
Conclusion: The results showed that there was a significant correlation between the increase in contact time, temperature rise and turbidity reduction with inactivation efficiency of lamp)p<0.001(. Also the effect of the lamp on inactivation of larvae nematode was more than the adults.


Photocatalytic Removal of Aniline from Synthetic Wastewater using ZnO Nanoparticle under Ultraviolet Irradiation
Emad Dehghani Fard, Ahmad Jonidi Jafari, Roshanak Rezae Kalantari, Mitra Gholami, Ali Esrafili,
Volume 5, Issue 2 (10-2012)
Abstract
MicrosoftInternetExplorer4 Background and Objectives: Aniline has been used in different processes of chemical industries, however due to its side effects on the environment, several methods have been considered for its removal. In this study, we evaluated the performance of photocatalytic process using ZnO nanoparticles (nZnO) and ultraviolet (UV) irradiation for removal of Aniline from a synthetic effluent.
Materials and Methods: A 5L photocatalytic reactor made from Plexiglas, which the UV lamp (20w) installed in the center of that (inside a quartz jacket), was designed and nZnO (0.2-0.5 g/l) was being added into synthetic effluent with Aniline concentration of 250 ppm. After retention times of 30, 60, and 90 min, samples were centrifuged and supernatant was filtered using a 0.2 µ PTFE filter. The liquid-liquid method and Gas Chromatography instrument was used for extraction and analysis respectively.
Results: Results showed that the photocatalytic process of nZnO+UV could effectively remove Aniline from effluent. Increasing trend in the removal efficiency of Aniline using nZnO = 0.5 g/l was slower in comparison with other nZnO concentrations and the ANOVA analysis shows no significant difference between removal efficiency of Aniline in different concentrations of nZnO. The most removal efficiency of Aniline (76.3%) was observed in alkaline pH, retention time of 90 min and nZnO of 0.5 g/l.
Conclusion: It could be concluded that the photocatalytic process of nZnO+UV could be suitable technique for Aniline removal from effluents.


Toxicity Assessment of Perchloroethylene and Intermediate Products after Advanced Oxidation Process by Daphnia Magna Bioassay
Mahdi Sadeghi, Kazem Naddafi, Ramin Nabizadeh,
Volume 7, Issue 2 (10-2014)
Abstract

Background and objective: Perchloroethylene is a chlorinated hydrocarbon used as a solvent in many industries and services activities such as dry cleaning and auto industry as degreasing. We carried out a bioassay using Daphnia Magna in order to determine the ecological effects of wastewater treatment through applying advanced oxidation processes (ultrasonic, ultraviolet irradiation and hydrogen peroxide processes) for removal of perchloroethylene. Materials and Methods: Due to the sensitivity of Daphnia and reports indicating this species is the most sensitive aquatic invertebrate to a variety of organic compounds, toxicity of perchloroethylene and its intermediate degradation products during applying different processes was tested using Daphnia. Lethal concentration (LC50) and toxic units (TU) were determined. In to determine toxicity of perchloroethylene, its stock solution was prepared at a concentration of 100 mg/L. Then, nine samples each containing 0 (control), 5, 10, 20, 30, 40, 50, 75, and 100% by volume of the primary stock solution were prepared. To determine the toxicity of the intermediate products of perchloroethylene by ultrasonic, photolysis, photolysis with hydrogen peroxide and photosonic processes, an initial concentration of perchloroethylene for each reactor (100 mg/L) was taken. All experiments were carried out at the Laboratory of Microbiology, Faculty of Health, Tehran University of Medical Sciences, Iran. Results: It was found that the 24 h LC50 for perchloroethylene on Daphnia Magna was 35.51 mg /L. The 48 h, 72 h and 96 h LC50 of perchloroethylene were 28.058, 21.033, and 19.27 mg/L respectively. Toxicity of perchloroethylene was decreased after oxidation processes. Conclusion: The toxicity after hybrid processes was lower than the single processes. The toxicity reduction was the same during all time period. Hence, the hypothesis of reducing toxicity of the intermediate products of perchloroethylene degradation after the abovementioned processes is acceptable. It is noteworthy that although there are different intermediate compounds in the effluent of various chemical oxidation processes, , but they are less toxic compared with the original perchloroethylene this may be due to the partially concentration of intermediate products that will decrease toxicity.


Evaluation of solar ultraviolet radiation in Zanjan city using the ultraviolet index
Maryam Abdi, Seyed Reza Azimi Pirsaraei, Mohammad Reza Mohammadizadeh,
Volume 14, Issue 1 (5-2021)
Abstract
Background and Objective: Monitoring the amount of ultraviolet radiation from sunlight can provide a basis for assessing people's exposure, raise public awareness and warn people against this radiation. Measuring the sun's ultraviolet index over a working period is an accurate choice to achieve this goal.
Materials and Methods: In this study, the amount of solar UV index in one of the outdoor locations of Zanjan city was measured using Solarmeter model 5.6 UV index meter for one year period. Measurements were performed from 9 am to 5 pm every 30 minutes in direct sunlight in even days for one year period (2018-2019). Finally, the results were analyzed using Excel software.
Results: The highest value of the maximum daily UV index was related to July, with an average value of 11.87 ± 0.649; while, the lowest value of the maximum daily UV index obtained in January, with an average value of 2.23 ± 0.944. In most months of the year, except for late November, December, January and cloudy days, the average value of the maximum daily UV index around noon exceeds the UV index alert threshold set by the World Health Organization (WHO). Even for the safe time period during spring and summer, the average UV index can exceed the UV index warning threshold.
Conclusion: Determining the intensity of the sun's hourly UV radiation is important and necessary to increase the peoples’ and workers’ awareness working in the open environment, as well as to plan for protective measures in any place, especially in Zanjan.

Application of response surface methodology to optimize the ultraviolet/hydrogen peroxide process for the removal of Reactive Red 195 dye from aqueous solution
Mohamad Javad Zoqi,
Volume 14, Issue 3 (12-2021)
Abstract
Background and Objective: The most used dyes in textile industries are Azo Group dyes. Azo dyes have complex aromatic compounds, low chemical and biodegradable stability. Due to these properties, treatment of this type of wastewater by conventional methods will not meet environmental standards. The advanced oxidation process has been widely used to treat organic matter from wastewater. In this study, dye purification of azo dye Reactive Red 195 by UV/H2O2 process was investigated. Moreover, the parameters affecting this process have also been determined.
Materials and Methods: In this study, dye treatment was conducted in the presence of different concentrations of hydrogen peroxide, and at different retention time, temperature and pH values in a continuous photoreactor equipped with UV lamps. Using central composite design and response surface methodology (RSM), effects of various concentrations of hydrogen peroxide, retention time, temperature, and pH on the color and COD removal were studied in the range of 0–2%, 60-240 min, 25-80 oC, and 3-10, respectively.
Results: The results showed that the concentration of hydrogen peroxide and retention time were the most influential parameters on color and COD removal. Color removal significantly enhanced by increasing retention time and H2O2 concentration to 200 min and 1.2%, respectively. pH increase had positive effect on color removal. There were increases in the rate of color and COD removal as the temperature went up to 50 oC. However, temperature of 80 oC negatively impacted AOP process. According to RSM, the optimum factor levels were achieved at 1.28%, 240 min, 49 oC and 10 for concentrations of hydrogen peroxide, reaction time, temperature, and pH, respectively.
Conclusion: According to the result, UV/H2O2 proved to be capable of degrading Reactive Red 195. Almost all the azo dye color destroyed after 209 min while 87.52 % of the COD was removed after 240 min of irradiation.

Effectiveness of Ultraviolet-C light diode radiation using pulsed and continuous radiation in reducing the concentration of Escherichia coli
Elham Asrari, Hedieh Deyhim,
Volume 15, Issue 2 (8-2022)
Abstract
Background and Objective: The application of ultraviolet photolysis in the removal of microbial contamination can develop the use of wastewater sources. In this research, the efficiency of UVC-LED for removing Escherichia coli was evaluated in pulsed radiation mode with continuous radiation.
Materials and Methods: In order to conduct this research, 4 UVC-LEDs with a short wavelength of 12 MW were used to produce ultraviolet rays. LEDs create waves with a wavelength of 260-280 nm. The distance between the LED and the plates was considered to be about 0.5 cm, 1 cm, and 2 cm. In order to investigate the effect of discontinuous radiation on UVC-LED performance, 2 Hz and 1 Hz frequency were used. In this case, the power source is connected 2 times and 1 time respectively in every second. The variables of radiation time (t) in seconds, radiation distance (d) in centimeters, and radiation frequency (f) in Hz were used for valuation.
Results: The results showed that in discontinuous irradiation, although the effectiveness increases with the increase of irradiation time, and practically at times higher than 280 seconds, bacteria do not remain in the samples, but the performance of discontinuous irradiation compared to continuous irradiation in removing bacteria at irradiation intervals of 1 cm, 0.5 cm and time 20 s has only achieved logarithm 4 or in other words 99.99% removal, which is considered the weakest performance of continuous radiation. Also, in the discontinuous radiation mode, after 280 s time and 2 cm distance, the radiation performance towards the complete removal of bacteria is equal to the logarithm of 6 or 99.999%, which is equal to the amount of bacteria removal in continuous radiation.
Conclusion: The efficiency of pulsed radiation was greater as compared to continuous radiation.
 

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