Endüstri Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/279
Browse
4 results
Search Results
Article Citation - WoS: 3Citation - Scopus: 4Comparison of Classroom Furniture To Anthropometric Measures of Turkish Middle School Students(Ios Press, 2021) Erdogan, Filiz Celikci; Satir, BenhurBACKGROUND: The match between classroom furniture and students' anthropometry is an important factor in students' academic performance. OBJECTIVE: Our aim was to investigate the ergonomic suitability of the classroom furniture to the students, and to propose design suggestions for both desks and chairs. METHODS: We analyzed the ergonomics of classroom furniture that students aged 10-14 years old in Turkey currently use. To this end, we selected Maltepe Primary Education School, one of the largest schools in the cankaya district of Turkey's capital city, Ankara, in which to conduct the study. A sample of 119 students was selected, and seven anthropometric measurements were taken for each of these students. We then calculated five relationships between the dimensions of the furniture and the students' anthropometric measures. RESULTS: We observed high levels of mismatch rates, with an average of 66.6% and high values of over 95% for the relations of two furniture measures, seat depth (related with buttock-popliteal length) and seat-to-desk height (related with elbow height, sitting). Each anthropometric measure was applied a fit probability distribution, and based on those distributions; we suggested the most appropriate classroom furniture dimensions in order to maximize suitability of the furniture to the anthropometric measures in terms of fixed-size (i.e., non-adjustable) classroom furniture. CONCLUSIONS: High mismatch rates can be reduced by 52.0% on average based on the classroom furniture dimensions suggested in this study.Article Control of Trichloroethylene Emissions From Sparging Systems by Horizontal Bio- and Chemo-Barriers(Selper Ltd, Publications Div, 2005) Tezel, U; Demirer, GN; Uludag-Demirer, SThe scope of this study was to develop a continuous system to clean-up a trichloroethylene (TCE) contaminated gas stream, where biotic and abiotic removal mechanisms are undertaken sequentially simulating the horizontal bio- and chemo-barriers proposed for the in-situ remediation of the contaminated sites. The bio- and chemo-barriers were simulated by using glass columns packed with granular anaerobic mixed culture and Fe(0) filings, respectively. The effect of gas residence time, which is adjusted by the gas flowrate, on the TCE removal efficiency of the reactor system was investigated. TCE removal efficiency of over 90% was achieved at gas residence times above 1hr. Furthermore, the effluent of reactor system contained only ethane and ethylene, which are non-toxic by-products of TCE reduction reactions, along with trace amounts of TCE.Article Citation - WoS: 66Citation - Scopus: 85Removal of Ammonium and Phosphate From the Supernatant of Anaerobically Digested Waste Activated Sludge by Chemical Precipitation(Elsevier Sci Ltd, 2009) Uludag-Demirer, Sibel; Othman, MaazuzaThe removal of ammonium (NH4+) and phosphate (PO43-) from supernatant of anaerobic digestion by magnesium ammonium phosphate (MAP) formation was Studied. To be able to find out the loss of NH4+ by its transformation to NH3, rates of NH4+ removal by aeration and by MAP formation combined with aeration were compared. NH4+ removal by aeration was found to be insignificant. The kinetics of MAP formation was fast. The removal rate of NH4+ and Mg2+ was the smallest and the largest, respectively based on rate constants calculated. The removal of NH4+ showed sensitivity to Mg2+ and PO43- concentrations and controlled the purity of MAP precipitate. The removal of PO43- was found to be Sensitive to mainly Mg2+ ion. These results also indicated that as the supernatant Solution became more saturated in terms of MAP forming ions, the effect of pH increase became insignificant in the removal of ions from the solution. (C) 2009 Elsevier Ltd. All rights reserved.Article Citation - WoS: 98Citation - Scopus: 117Anaerobic Digestion of Dairy Manure With Enhanced Ammonia Removal(Academic Press Ltd- Elsevier Science Ltd, 2008) Uludag-Demirer, S.; Demirer, G. N.; Frear, C.; Chen, S.Poor ammonia-nitrogen removal in methanogenic anaerobic reactors digesting animal manure has been reported as an important disadvantage of anaerobic digestion (AD) in several studies. Development of anaerobic processes that are capable of producing reduced ammonia-nitrogen levels in their effluent is one of the areas where further research must be pursued if AD technology is to be made more effective and economically advantageous. One approach to removing ammonia from anaerobically digested effluents is the forced precipitation of magnesium ammonium phosphate hexahydrate (MgNH4PO4-6H(2)O), commonly called struvite. Struvite is a valuable plant nutrient source for nitrogen and phosphorus since it releases them slowly and has non-burning features because of its low solubility in water. This study investigated coupling AD and controlled struvite precipitation in the same reactor to minimize the nitrogen removal costs and possibly increase the performance of the AD by reducing the ammonia concentration which has an adverse effect oil anaerobic bacteria. The results indicated that Lip to 19% extra COD and almost 11% extra NH3 removals were achieved relative to a control by adding 1750 mg/L of MgCl2-6H(2)O to the anaerobic reactor. (C) 2007 Elsevier Ltd. All rights reserved.