Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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  • Book Part
    Citation - Scopus: 4
    Performance Analysis of Single-Flash Geothermal Power Plants: Gas Removal Systems Point of View
    (Nova Science Publishers, Inc., 2013) Ozcan,N.Y.; Gokcen,G.
    Non-condensable gases (NCGs), natural components of geothermal fluids, affect the performance of a geothermal power plant (GPP) significantly. Therefore, the NCGs should be removed from the process to optimise the thermodynamic efficiency of the plant. GPPs require large capacity NCG removal systems that occupy large portion in the total plant cost and auxiliary power consumption. The flashed-steam GPPs, which are commonly used in the World, are a relatively simple way to convert geothermal energy into electricity when the geothermal wells produce a mixture of steam and liquid. The primary aim of this study is to develop a code for simulating flashed-steam GPPs to examine the thermodynamic performance of NCG removal systems, which represent major concerns at planning and basic design stages of GPPs. A single-flash GPP model is developed and simulated to identify the effects of input variables, such as NCG fraction, separator pressure and condenser pressure. Among the variables, NCG fraction is the most significant parameter affecting thermodynamic performance of single-flash GPPs. The net power output and overall exergetic efficiency of single-flash GPP are decreased 0.4% for compressor system (CS), 2.2% for hybrid system (HS), 2.5% for reboiler system (RS), and 2.7% for steam jet ejector system (SJES) by 1% increase in NCG fraction. © 2014 Nova Science Publishers, Inc. All rights reserved.
  • Book Part
    Water Sorption of Polyvinyl Chloride-Luffa Cylindrica Composites
    (Nova Science Publishers, Inc., 2010) Demir,H.; Balköse,D.
    Natural Luffa Cylindrica fibers were modified with 0.1M sodium hydroxide (NaOH) for removing lignin and hemicellulose. Natural and modified Luffa fibers were characterized by using IR spectroscopy. Composites were produced with PVC plastisol and natural Luffa fiber. Natural Luffa fiber is a highly hydrophilic substance. This feature increased the water sorption capacity of the composites. Flexible PVC-luffa cylindrica composites had higher liquid water sorption capacity (0.3-0.6%) compared to that of flexible PVC (0.1%). There was no volume change of composites due to liquid water sorption. © 2014 by Nova Science Publishers, Inc. All rights reserved.
  • Book Part
    An Effect of Climate Change: Increased Health Risks Due To Arsenic in Drinking Water - the Case of İzmir, Turkey
    (Nova Science Publishers, Inc., 2010) Sofuoglu, S.C.; Sofuoglu, A.
    Our previous research (Kavcar et al., 2009) has shown that tap water arsenic concentrations in the City of İzmir, Turkey, was of concern as arsenic in 15 of 37 (41%) of the tap water samples (collected in the year 2004) exceeded the Turkish drinking water standard of 10 µg/L (TMH, 2005). The median, mean, and 95th percentile concentrations were 2.9, 12.0, and 42.0 µg/L, respectively. The violations of the standard were in three districts, i.e., Bornova, Çiğli, and Karşıyaka, that were served primarily by groundwater sources. The concentrations in other districts were below the standard. However, concentrations less than the standard may be associated with a carcinogenic risk that is greater than the acceptable risk level of one in ten thousand depending on the level of exposure, mainly, daily drinking water intake rate and body weight. This was the case for the City of İzmir as lifetime carcinogenic risks exceeded the acceptable level for 19 of the 37 participants (51%). As the result of the above cited research, the local government has shut-down a number of groundwater wells as a mitigation measure. In turn, the concentrations were brought down to <15 µg/L in the three districts by increasing the proportion of surface water supplied from Tahtalı Reservoir. However, climate change has been affecting the region. The water volume in the resevoir was dropped below 5% in 2008. As a result, the arsenic contaminated wells were brought back into the service, causing a sharp increase in the arsenic concentrations, this time all around the city, measured by the local health authority. İzmirians who can not afford to buy bottled drinking water are (to be) exposed to arsenic concentrations of 30-40 µg/L until the planned treatment plant is in place. A probablistic risk assessment was conducted to estimate the human health risks for the scenario of no available surface water, in which no treatment and treatment with 90% and 99% efficiencies were assumed for the arsenic contaminated groundwater, based on the concentrations measured by the local health authority. The median carcinogenic risk estimated for the scenario of no treatment for the metropolitan area was approximately eight times the median value estimated when the main source water was Tahtalı Reservoir, a surface water dam. © 2008 Nova Science Publishers, Inc.