Fahime Khademi; Mohammad Reza Samaei; Kourosh Azizi; Abbas Shahsavani; Hassan Hashemi; Aida Iraji; Abdolkhalegh Miri
Volume 4, Issue 1 , January 2016, , Pages 2-6
Abstract
AbstractBackground: Biogas is obtained by anaerobic decomposition of organic wastes buried materials used to produce electricity, heat and biofuels. Biogas is at the second place for power generation after hydropower and in 2000 about 6% of the world power generation was allocated to biogas. Biogas is ...
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AbstractBackground: Biogas is obtained by anaerobic decomposition of organic wastes buried materials used to produce electricity, heat and biofuels. Biogas is at the second place for power generation after hydropower and in 2000 about 6% of the world power generation was allocated to biogas. Biogas is composed of 40–45 vol% CO2, 55–65 vol% CH4, and about 1% non-methaneVOCs, and non-methane volatile organic compounds. Emission rates are used to evaluate the compliance with landfill gas emission regulations by the United States Environmental Protection Agency (USEPA). BTEX comounds affect the air quality and may be harmful to human health. Benzene, toluene, ethylbenzene and xylene isomers that are generally called BTEX compounds are the most abundant VOCs in biogas.Methods: Sampling of VOCs in biogas vents was operated passively or with Tedlar bags. 20 samples were collected from 40 wells of old and new biogas sites of Shiraz’ landfill. Immediately after sampling, the samples were transferred to the laboratory. Analysis of the samples was performed with GC-MS.Results: The results showed that in the collection of the old and new biogas sites, the highest concentration of VOCs was observed in toluene (0.85ppm) followed by benzene (0.81ppm), ethylbenzene (0.13ppm) and xylene (0.08ppm).Conclusion: The results of the study showed that in all samples, most available compounds in biogas vents were aromatic hydrocarbon compounds.These compounds’ constituents originate from household hazardous waste materials deposited in the landfill or from biological/chemical decomposition processes within the landfill.
Asma Kazemi; Zahra Hassanzadeh Rostami; Masoumeh Akhlaghi
Volume 2, Issue 3 , July 2014, , Pages 93-98
Abstract
Background: The association between snacking patterns, sleep hours, and physical activity with growth status and appetite of preschool children was investigated.Methods: Sixty three children aged 3-7 years with low appetite and weight for age ratio below the 25th percentile were enrolled from those referring ...
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Background: The association between snacking patterns, sleep hours, and physical activity with growth status and appetite of preschool children was investigated.Methods: Sixty three children aged 3-7 years with low appetite and weight for age ratio below the 25th percentile were enrolled from those referring to Nader Kazemi Polyclinic in Shiraz. Information regarding the parents’ education, sleep hours, physical activity, appetite, and snacking patterns was obtained by interview. Height and weight were measured and energy intake was estimated by 2-day food recall. Appetite was rated on a 5-point scale based on the maternal report.Results: Mother’s education, the number of children in the household, and physical activity were not associated with either growth failure, energy intake, or appetite, but the fathers’ education more than Diploma was associated with higher energy intake in children (P=0.015). Children who slept <11 hours a day had higher energy intake (P=0.026) but worse weight status (P=0.015). Children who always ate snacks close to the main meals had significantly higher energy intake but more severe growth failure. High consumption of fruit drinks, cakes, and potato chips was associated with exacerbated growth faltering whereas nuts consumption was related to better height status. None of the evaluated parameters was associated with children’s appetite.Conclusion: Overall, the results suggest the importance of sufficient sleep, limited consumption of snacks, and the type and time of snack consumption in growth of children with poor appetite. Nutritious snacks such as nuts may be more beneficial than nutrient-poor snacks for growth of children.
