Browsing by Subject "ENERGY-CONSUMPTION"

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    Income inequality and CO2 emissions: Empirical evidence from Turkey
    (SAGE PUBLICATIONS LTD) Demir, C; Cergibozan, R; Gök, A
    The aim of the study is to investigate the impact of income inequality on environmental quality in Turkey within the Environmental Kuznets Curve framework. In order to observe the short-run and long-run effects of income inequality on environmental quality, an autoregressive distributed lag bounds test on CO2 emission has been employed for the period 1963-2011 of Turkey. The results of the analysis reveal that there is a negative association between CO2 emission level and income inequality, which implies that increasing income inequality reduces environmental degradation in Turkey. Hence, a greater inequality in the society leads to less aggregate consumption in the economy due to lower propensity to emit in the richer households resulting in better environmental quality. The findings confirm an argument in the existing literature, which suggests that for developing countries, until a certain level of development, environmental degradation increases as income inequality in the society decreases. The results also confirm the Environmental Kuznets Curve hypothesis.
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    Investigation of machinability properties of AISI H11 tool steel for sustainable manufacturing
    (SAGE PUBLICATIONS LTD) Sahinoglu, A
    In this experimental study, vibration, energy consumption, power consumption and surface roughness values that occur in the machining of AISI H11 tool steel under CO2, coolant and dry cutting conditions were investigated. The effects of different cutting parameters and cooling systems on machinability were investigated. Analysis of variance was done. Regression equations were obtained. Relationships between power consumption, vibration and surface roughness are explained with mathematical equations. Finally, the optimum CC were determined by the multiple optimization methods. According to the test results, while the instantaneous power consumption increases by increasing cutting parameters, energy consumption decreases as the processing time is shortened. Vibration value increases by increasing cutting parameters. The highest vibration value occurs in cutting with CO2. Compared to dry and CO2 cutting, the vibration is lowest in coolant cutting. The friction decreases with the coolant and the vibration value decreases. There is a similar relationship between vibration and surface roughness value. The most effective parameter on the surface roughness value is the feed rate. It was seen that the most suitable CC for the most efficient cutting, the lowest energy consumption, vibration and surface roughness value, under coolant cutting, 0.2 mm depth of cut, 175 m/min cutting speed and 0.119 mm/rev feed rate. With optimum CC, the vibration value was reduced by 5.18%, the surface roughness value by 37.12%, energy consumption by 36.19% and the machine efficiency was increased by 7.16%.
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    Numerical evaluation of pedestrian-level wind and indoor thermal comfort of a historical monument, Mugla, Turkey
    (EMERALD GROUP PUBLISHING LTD) Gençer, F; Karadag, I
    Purpose The study aims to analyze both thermal and wind comfort conditions of a historical mosque's interior and outdoor spaces for the planning of further conservation decisions. Design/methodology/approach The method is composed of two steps. First, thermal comfort analyses are conducted via Design-Builder Software. The predicted mean vote (PMV) and predicted percentage of dissatisfied indices were calculated and evaluated using the ASHRAE 55-2010 standard. Thermal comfort conditions are analyzed with the proposed three operations. Second, wind comfort analyses are conducted via computational fluid dynamics (CFD) software. Outdoor thermal comfort conditions are predicted by air temperature, mean radiant temperature, wind speed and relative humidity. Findings The (PMV) in the harim was calculated as -1.83 (cool) which corresponds to a predicted percentage of dissatisfaction (PPD) equal to 68.54%. Thermal comfort was provided by daytime and continuous operations; however, intermittent operations did not provide thermal comfort. The wind velocities around the mosque are well below the 5 m/s limit value for standing defined by NEN 8100 wind nuisance standard. Moreover, the limit value of 2.5 m/s for sitting was also satisfied with more than 80% of the semi-enclosed area around the entrance of the mosque. Last comer's hall remains in a slight cold stress range, the rest of the areas have no thermal stress. Originality/value This two-stage study creates a base for further improvements to provide comfort conditions in a historical building without interfering with its original features.
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    Thermoelectric generation in bifurcating channels and efficient modeling by using hybrid CFD and artificial neural networks
    (PERGAMON-ELSEVIER SCIENCE LTD) Selimefendigil, F; Öztop, HF
    Thermoelectric power generation within TEG mounted branching channels is considered with finite element method. In the heat transfer fluid of bifurcating channels, nanodiamond + Fe3O4 binary particles are used for further system performance improvement. It was observed that when compared to non bifurcating channels, TEG power will be reduced with the use of branching channels while branching location also affects the interface temperature variations. At (Re-1, Re-2)=(1000, 200), TEG power is reduced 34.7% when both channels are branching while it is 9.9% for only upper channel branching case as compared to non-branching channel case. Up to 18% variation of power is obtained when location of the upper branching channel varies. Highest powers are achieved when both channels are filled with hybrid nanofluid while at (Re-1, Re-2) = (1000, 200) TEG power rises by about 33% and 15.5% with nanofluid in both channels and with nanofluid in only one channel cases when compared to fluid in both channel configuration. The computational cost of electric potential and power generation in TEG device is drastically reduced from 6 hours with fully coupled high fidelity CFD to 3 minutes by using hybrid CFD and artificial neural networks. The proposed approach will very helpful in the efficient design and optimization of TEG installed renewable energy systems. (c) 2021 Elsevier Ltd. All rights reserved.