WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collections

Permanent URI for this collectionhttps://hdl.handle.net/20.500.13091/2

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Now showing 1 - 20 of 33

Citation - WoS: 50
Citation - Scopus: 55
Advanced Oxidation of Landfill Leachate: Removal of Micropollutants and Identification of By-Products
(ELSEVIER, 2021) Ateş, Havva; Argun, Mehmet Emin
Landfill leachate contains several macropollutants and micropollutants that cannot be removed efficiently by conventional treatment processes. Therefore, an advanced oxidation process is a promising step in post or pre-treatment of leachate. In this study, the effects of Fenton and ozone oxidation on the removal of 16 emerging micropollutants including polycyclic aromatic hydrocarbons (PAHs), phthalates, alkylphenols and pesticides were investigated. The Fenton and ozone oxidation of the leachate were performed with four (reaction time: 20-90 min, Fe(II) dose: 0.51-2.55 g/L, H2O2 dose: 5.1-25.5 g/L and pH: 3-5) and two (ozonation time: 10-130 min and pH: 4-10) independent variables, respectively. Among these operating conditions, reaction time played more significant role (p-value < 0.05) in eliminating di-(2-Ethylhexyl) phthalate, 4-nonylphenol and 4-tert-octylphenol for both processes. The results showed that Fenton and ozone oxidation processes had a high degradation potential for micropollutants except for the PAHs including four and more rings. Removal efficiencies of micropollutants by ozone and Fenton oxidation were determined in the range of 5-100%. Although the removal efficiencies of chemical oxygen demand (COD) and some micropollutants such as phthalates were found much higher in the Fenton process than ozonation, the degradation products occurred during the Fenton oxidation were a higher molecular weight. Moreover, the oxidation intermediates for the both processes were found as mainly benzaldehyde, pentanoic acid and hydro cinnamic acid as well as derivatives of naphthalenone and naphthalenediol. Also, acid ester with higher molecular weight, naphthalene-based and phenolic compounds were detected in the Fenton oxidation.
Citation - WoS: 3
Application of the Shrinking-Core Models for Determination of Dissolution Kinetics of Mn and Zn From Spent Zinc-Carbon Battery Powder in Organic Acid Solution
(SCIENDO, 2019) Ağaçayak, Tevfik; Taner, Hasan Ali
In this study, dissolution kinetics of manganese and zinc from spent zinc-carbon batteries in acetic acid solution was investigated. To determine the kinetics of dissolution of manganese and zinc, shrinking core model was applied to dissolution recoveries obtained at different temperatures. As a result of kinetic studies, it was determined that manganese and zinc were dissolved in acetic acid solution by diffusion from product layer and then activation energies (Ea) were calculated.
Citation - WoS: 16
Citation - Scopus: 17
Assessment of Natural Radioactivity Level of Soil and Water in the Region of Corlu (turkey)
(SPRINGER, 2021) Manisa, Kaan; Erdoğan, Mehmet; Usluer, Ali; Çetinkaya, Hakan; Işık, Ulaş; Şahin, Latife; Zedef, Veysel
The activity concentrations of Rn-222 with an AlphaGUARD system in well having different depths and in natural spring waters were measured to assess the natural radioactivity level of the corlu region. The measured concentrations varied from 22.04 to 63.92 Bq L-1 for 6 well water samples, 15.38-24.33 Bq L-1 for 6 spring water samples. The activity concentrations from U-238, Th-232 and K-40 in 11 soil samples collected from the same region were also determined and the outdoor gamma dose rates at 1 m above the surface at the same sampling points were measured. The results obtained in this study lie within safe limits recommended by WHO and UNSCEAR with the exception of the mean specific activity of K-40 radionuclide.
Citation - WoS: 2
Citation - Scopus: 4
Assessment of the Effect of Blasthole Design Parameters on Total Cost in Quarries
(SPRINGER HEIDELBERG, 2020) Bilim, Niyazi; Çelik, Arif; Kekeç, Bilgehan
Crushed stone is the most important raw material for concrete and asphalt production. As a high-volume low-unit-value industry, the crushed stone production sector is highly competitive which implies the necessity to optimise the costs of all of its production operations, i.e. drilling and blasting, secondary breaking, loading, hauling and crushing. In this context, this paper investigates the effect of bench blasting design parameters on the unit-costs and total production cost of aggregate production. For this purpose, 40 blasts were conducted and investigated. The studied parameters included different blasthole length (12 m, 15 m, 18 m, 21.5 m and 25 m) and diameter (89 mm and 102 mm), in addition to different spacing, burden and stemming length. As a result, it was found that an increase in blasthole length led to an increase in the unit cost of drilling operation. In addition, it was found that a blasthole length of 15 m ensured optimum fragmentation, diminishing the costs of subsequent operations. Incrementing the blasthole diameter from 89 to 102 mm reduced the total unit cost by 0.091 $/m(3). Incrementing the burden and spacing by 0.25 m also decreased the total unit cost by 0.097 $/m(3). However, accreting the stemming length by 0.5 m induced a slight decrease in the total unit cost by 0.026 $/m(3).
Cleaning of Beysehir (bayavsar) Coal in Turkey With Hydrophobic Flocculation Using Waste Motor Oil
(Univ Alexandru Ioan Cuza Iasi, Editura Univ, 2021) Ağaçayak, Tevfik; Ağca, Osman
In this study, the hydrophobic flocculation behavior of lignite coal obtained from Beysehir region in Turkey and the effect of some parameters were investigated. These parameters were selected as pH, amount of dispersant, amount of binding liquid, flock growth time, stirring speed, flocculation time and solid ratio. The ash content (ash, %) and combustible recovery (CR, %) of the flocks obtained as a result of the experiments were determined. As a result of the studies, the optimum pH value (3), amount of sodium silicate (1 mL), amount of waste motor oil (3 mL), flock growth time (1 min), stirring speed (1250 rpm), flocculation time (2 min) and solid ratio (5 g) were determined. The hydrophobicity of fine coal grains was increased by using waste motor oil. According to the hydrophobic flocculation results of coal grains, flocks with 17.03% ash content and 99.06% combustion recovery were obtained. While the contact angle of the original coal was 44 degrees, it was observed that the contact angle of the obtained flocks reached 117 degrees. It was determined from experiments that the surfaces of the coal grains have a very high hydrophobicity. As a result, clean coal with a reduced ash content of 53.22% was obtained.
Citation - WoS: 36
Citation - Scopus: 43
Comparison of Advanced Biological Treatment and Nature-Based Solutions for the Treatment of Pharmaceutically Active Compounds (phacs): a Comprehensive Study for Wastewater and Sewage Sludge
(ELSEVIER, 2021) Nas, Bilgehan; Dolu, Taylan; Argun, Mehmet Emin; Yel, Esra; Ateş, Havva; Koyuncu, Serdar
Passing of pharmaceutical residues into environment in an uncontrolled manner as a result of continuous increase in drug consumption across the globe has become a threatening problem for the ecosystems and almost all living creatures. In this study, diclofenac (DCF), carbamazepine (CBZ), 17 beta-estradiol (17 beta-E2) and 17 alpha ethynylestradiol (EE2) belonging to different therapeutic classes were investigated simultaneously in advanced biological treatment and nature-based treatments during 12-months sampling campaign. In this context, behavior patterns of pharmaceutically active compounds (PhACs) throughout the both wastewater and sludge lines in advanced biological wastewater treatment plant (WWTP), wastewater stabilization pond (WSP) and constructed wetland (CW) were discussed in detail based on each treatment processes seasonally. Furthermore, statistically evaluated data obtained in full-scale WWTPs were compared with each other in order to determine the valid removal mechanisms of these pharmaceutical compounds. While DCF and CBZ were detected very intensively both in the wastewater and sludge lines of the investigated WWTPs, steroid hormones,17 beta-E2 and EE2, were determined below the LOQ value in general. Annual average removal efficiencies achieved in studied WWTPs for DCF ranged between & minus;23.3% (in CW) and 75.2% (in WSP), while annual average removal rates obtained for CBZ varied between & minus;20.7% (in advanced biological treatment) and 10.0% (in CW). It has been found that DCF was highly affected by different wastewater treatment processes applied in the WWTPs compared to CBZ which showed extraordinary resistance to all different treatment processes. Although calculated in different rates for each compounds, biodegradation/biotransformation and sorption onto sewage sludge were determined as the main removal mechanisms for PhACs in plants. Although showed a similar behavior in the sludge dewatering unit (decanter) present in the advanced biological WWTP, quite different behaviors ob-served in the anaerobic digester for DCF (up to 15% decrease) and CBZ (up to 95% increase). Sorption and desorp-tion behaviors of DCF and CBZ were also evaluated in the sludge treatment processes found in advanced biological WWTP. Percentages of originated extra annual average of pharmaceutical loads were calculated as 0.64% and 0.90% for DCF and CBZ, respectively in the advanced biological WWTP due to the sidestream caused by the sludge dewatering unit. (c) 2021 Elsevier B.V. All rights reserved.
Determination of Optimum Flotation Conditions in Nigde (ulukisla) Complex Pb-Zn Ore
(Pamukkale Univ, 2021) Ağaçayak, Tevfik; Yılmaz, Nur Benan
In this study, optimum flotation conditions of Pb-Zn complex ore from Nigde-Ulukisla region were investigated. The liberalization grain size (d(80)) of the ore sample to be used in experimental studies was determined and mineralogical analyzes were performed. Flotation experiments were performed at 30% solid ratio, 10 L/min air flow rate, 1250 rpm stirring speed and pH=9. Reagents and their amounts were determined in grinding, Pb and Zn rough flotation circuits. 8 minutes in the grinding circuit, 4 min in Pb Circuit and 5 min in Zn circuit were applied to in the experiments. As a result, The lead grade of lead concentrate for 55.13%, the recovery for 80.30%, and zinc grade of zinc concentrate for 37.32%, the recovery for 77.60% were obtained.
Citation - WoS: 12
Citation - Scopus: 12
Effect of Organic and Inorganic Compounds on Dissolution Kinetics of Chalcopyrite in Hydrogen Peroxide- Hydrochloric Acid System
(Elsevier, 2022) Abdelraheem, Mohamed Taha Osman; Agacayak, Tevfik
The addition of 2-Propanol as an organic substance and NaCl as an inorganic com-pound in hydrochloric acid with hydrogen peroxide as a strong leaching agent of chalcopyrite was investigated. The effects of the leaching parameters on copper extraction, such as stirring speed, H2O2 concentration, temperature, HCl concentration and solid/liquid ratio were studied. The max-imum final copper extraction of 54.55% was obtained with 600 rpm stirring speed, 1.5 M H2O2, 0.5 M HCl, 600 rpm, 50 C, 240 min of the reaction and particle size of -106 +75 mm. Further experiments were performed when the solid-to-liquid ratio (S/L), stirring speed, temperature, HCl,H2O2 and leaching time were kept constant to examine the influence of NaCl and 2-Propanol concentrations in the range of 0-0.5 M and 0-3 M, respectively. The results showed that the copper extraction was increased up to 58.11% with addition of NaCl. While copper extraction yield reached 94.25% in case of addition of 2-propanol with the optimum parameters(0.5 M HCl,50 C, 1.5 M H2O2, 600 rpm, particle size -106 +75 lm, solid liquid ratio 2g/L, 3 M 2-propanol). The chalcopyrite leaching in hydrogen peroxide- hydrochloric acid system was found to be described by the interface transfer and diffusion across the product layer with activation energy of 77.14 kJ/mol. Addition of 2-propanol suggested that the reaction was under product layer diffusion control and decreased the activation energy of chalcopyrite leaching to 67.98 kJ/mol. Crown Copyright (c) 2022 Published by Elsevier B.V. on behalf of King Saud University.
Citation - WoS: 6
Citation - Scopus: 7
Estimation of Specific Energy and Evaluation of Roadheader Performance Using Rock Properties and Bond Work Index
(SPRINGER HEIDELBERG, 2021) Özşen, Hakan; Dursun, Arif Emre; Aras, Ali
Specific energy (SE) is defined as the amount of work required to cut a unit volume of rock and is used to estimate the performance of excavation machines. Generally, the SE value is produced from full-scale or small-scale rock cutting tests. However, these tests require expensive equipment and experienced personnel, and the testing procedure is time consuming and impractical. Therefore, for estimation of SE, this study aimed to find a solution to estimate SE using rock mechanics test results and Bond work index values (BWi), which can be produced in a more practical, less time-consuming manner and with inexpensive test equipment. Small-scale rock cutting, rock mechanics and Bond work index tests were carried out on seven rock samples, which can be grouped into two different type of rocks: marble and travertine. In addition, the instantaneous cutting rates (ICR) of a selected roadheader were calculated using SE values. Rock mechanics tests performed in this study were uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), ultrasonic velocity (V-p), Schmidt rebound hardness (R-L), corrected point load index (I-s(50)) and density (rho). The simple regression method was used to estimate SE from rock properties and BWi. As a result of this simple regression, a significant and highest correlation was found between SE vs. UCS and I-s(50). A good correlation was found between SE vs. BTS, R-L and BWi values. A moderate correlation was found between SE vs. V-p and rho.
Citation - WoS: 5
Citation - Scopus: 7
Estimation of the Risk of Work-Related Accidents for Underground Hard Coal Mine Workers by Logistic Regression
(TAYLOR & FRANCIS LTD, 2022) Bilim, Niyazi; Bilim, Atiye
Coal mining has the most risk in all of the mining sectors. Hence, in this sector, most work accidents encountered are intensive. The demographic characteristics of workers affect the occurrence of occupational accidents. This study aims to develop an equation that predicts workday loss by analyzing the relationship between workers' demographic characteristics and having an accident with workday loss. In this study, work-related accidents between 2014 and 2019 in underground hard coal mines in Turkey were analyzed using logistic regression analysis. An equation is derived that estimates the workday loss with the characteristics of workers in hard coal mines. With the equation derived in this study, employers can determine the potential for work accidents according to the demographic characteristics of the workers and serious work accidents will be prevented. Therefore, proactive solutions can be produced by applying the methods used in this study to different industries.
Citation - WoS: 17
Citation - Scopus: 19
Fate of Pahs Under Subcritical and Supercritical Conditions in Landfill Leachate: Removal or Formation?
(ELSEVIER SCIENCE SA, 2021) Ateş, Havva; Argun, Mehmet Emin
In this study, fate of eight polycyclic aromatic hydrocarbons (PAHs) described as priority pollutants by the European Union during the subcritical and supercritical water oxidation (SCWO) of landfill leachate was investigated. The experiments were conducted under the temperature of 250?500 ?C, pressure of 10?35 MPa, residence time of 2?18 min and dimensionless oxidant dose (DOD) of 0.2?2.3. The results revealed that the SCWO process had a high potential for degradation of PAHs except for four and more rings from leachate having high organic and inorganic pollutant loads. The removal efficiencies of chemical oxygen demand (COD), naphthalene (NAP), anthracene (ANT) and fluoranthene (FL) increased up to 98%, 97%, 95%, and 87%, respectively. However, the high removal efficiencies of COD did not directly correlate with the removal of PAHs. 2- to 4-ring PAHs increased in subcritical and supercritical conditions at 0.4 DOD. Additionally, PAH compounds such as pyrene and chrysene not found in raw leachate were detected in some treated samples at low DOD and high temperature. It was concluded that aromatic substances detected in the leachate could transform to naphthalene, anthracene and fluoranthene with merger/separation reactions. On the other hand, aldehyde, ketone and phenol-based compounds were detected as the transformation products when the oxidation mechanism was dominant. Therefore, optimum experimental conditions that aimed to both minimize PAHs formation and maximize COD removal were determined as 7 min, 2 DOD, 375 ?C and 22.5 MPa.
Citation - WoS: 2
Citation - Scopus: 2
The Geological-Geochemical Characteristics of the Binbir Church (karaman, Turkey) Archaeological Site and the Alteration of the Rocks Used in the Buildings
(Springer, 2022) Horasan, Bilgehan Yabgu; Yüksel, Onur; Öztürk, Alican
Karaman (Turkey) province, formerly known as Lykaonia, has a wide range of geographically diverse raw materials, has hosted many civilisations throughout history, and provides remains of these civilisations to the present day. The area where the ruins of Madensehir and Degle villages are located, namely, in the northern part of Karadag (Karaman, Turkey) is called Binbir Church. This area, which has been understood as a sacred centre since the Hittites period, has strategic importance in terms of its geographical location in the Late Roman and Byzantine periods. It also became the most significant religious centre of the region during the Byzantine period. The building stones used in the basilicas numbered 1, 31, and 32 in the villages of Madensehir and Degle, located in the ruins of a thousand and one churches, are dacite, trachydacite, and trachyandesite. SiO2-poor andesite and dacites were used in the structures, and it was understood that these rocks were very slightly or slightly altered according to the degree of alteration using the weathering index (of parker), the chemical index of the alteration, chemical index of weathering and the plagioclase index of alteration. The study of this region, which is a cultural heritage, is expected to lead to significant contributions to long-term restoration works to be carried out in the region.
Citation - WoS: 5
Citation - Scopus: 4
Improvement of Colemanite Flocculation With Collectors by Ultrasound Treatment
(TAYLOR & FRANCIS INC, 2022) Özkan, Alper; Eşmeli, Kiraz
In this study, the influence of ultrasound on the stability of colemanite suspension was first studied without reagents, and the effects of ultrasound power value, treatment regime (batch and continuous), probe immersion depth, and treatment time on the suspension stability were determined. Then, the effects of ultrasound on the flocculation of colemanite with sodium dodecyl sulfate, Aero 845, and sodium oleate were investigated, and changes occurred in the flocculation efficiency, zeta potential and contact angle values were shown depending on the collector concentration. The experimental findings revealed that the application of ultrasound reduced the suspension stability; that is, enhanced flocculation of colemanite particles occurred due to the ultrasonic promotion. By the ultrasonic treatment, the contact angles measured on the mineral surface in the presence of these collectors increased. In addition, the ultrasonic treatment led to increases in the surface charge of colemanite mineral with these surfactants. These results indicated that the ultrasound increased the adsorption of collectors on the mineral surfaces, as a result of this, the hydrophobization of the colemanite surfaces improved, and thus the flocculation of colemanite enhanced.
Citation - WoS: 2
Citation - Scopus: 2
Improvement of Lignite Flocculation by Ultrasound Pre-Treatment and Performance Optimization Using Box-Behnken Design
(Taylor & Francis Inc, 2022) Esmeli, K.
There were two objectives of this study. The first was to investigate the influence of ultrasound treatment on coal flocculation in the presence of polymers. In this context, it was observed that the flocculation success increased by using ultrasound as a pre-treatment, but flocculation did not occur with its application in the flocculation phase (ultrasound-induced flocculation only). Also, the short-term application of ultrasound pre-treatment at high power created a more positive effect. In the flocculation process with polymers, the use of ultrasound treatment as a pre-treatment for the suspension enhanced the aggregation of coal particles. In addition, the ultrasound pre-treatment reduced the magnitude of the zeta potential of coal with anionic polymer, which also supported the flocculation. The second objective of the study was to determine the influence of variables related to stirring speed, flocculation time, polymer concentration, and pH on flocculation efficiency by using Box- Behnken design. With the Box-Behnken design, it was found that the optimal conditions for flocculation efficiency were a stirring speed of 300 rpm, a flocculation time of 4 min, a polymer concentration of 1 mg/L, and pH-7, and these values were consistent with experimental results.
Citation - WoS: 3
Citation - Scopus: 2
Improvement of Lignite Oil Agglomeration by Ultrasound Process Using Waste Engine Oil
(Taylor & Francis Inc, 2022) Esmeli, K.
In the present study, it was aimed to clean fine coal with waste engine oil using the ultrasound process. The influence of ultrasound on the oil agglomeration of coal was determined using ultrasound at the pretreatment stage and at the agglomeration stage. In this context, the use of ultrasound at the pretreatment stage improved the oil agglomeration of coal, but the use of ultrasound at the agglomeration stage reduced the recovery of combustible matter. Also, the power of ultrasound and the time of treatment affected the success of agglomeration, and the optimal values were achieved at a power of 30 W of ultrasound and a treatment time of 3 min. In addition, the best ash content and combustible matter recovery values were obtained at the oil dosage value of 3 mL, but higher oil dosages adversely affected the success of agglomeration. Under optimal conditions, coal with an ash content of 15.02% was obtained with an efficiency of 61.29% in conventional experiments, while coal with an ash content of 9.65% with ultrasound pretreatment was obtained with an efficiency of 71.04%. These results show that ultrasound pretreatment is an effective method for the enrichment of fine particle coal.
Citation - WoS: 8
Citation - Scopus: 8
Indoor Radon Activity Concentration and Effective Dose Rates at Schools and Thermal Spas of Ilgin
(VINCA INST NUCLEAR SCI, 2020) Erdoğan, Mehmet; Abaka, Murat; Manisa, Kaan; Bircan, Hasan; Kuş, Coşkun; Zedef, Veysel
Indoor radon activity concentrations and radon doses on the ground floor and basement floor of 19 schools (kindergardens, primary schools, secondary schools, and high schools) and thermal spas of Ilgin district in Konya, have been measured using the AlphaGUARD PQ 2000PRO radon detector, for three days in the first half of 2016. According to the results, while the indoor radon concentration for only one location, in total, is above the Turkish action level of 400 Bqm(-3), the values for 10 locations are above the reference level of 100 Bqm-3, recommended by WHO. The calculated annual effective doses for inhalation of the radon in indoor air were also found to be 0.26 mu Sv for the minimum and 4.36 mu Sv for the maximum. The parametric distribution analysis is also performed with 3-parameter Weibull distribution and some remarks are provided on radon concentration activity.
Citation - WoS: 8
Citation - Scopus: 9
An Insight on the Impact of Covid-19 on the Global and Turkish Mining Industry
(Ios Press, 2022) Kekeç, Bilgehan; Bilim, Niyazi; Ghiloufi, Dhikra
BACKGROUND: COVID-19 affected numerous industries and the mining industry has not been immune to the adverse impacts caused by the pandemic. OBJECTIVE: This study examines the importance of the mining industry and its benefits to the economy of the producing countries. The paper also gives an insight into the pre-COVID global and Turkish mining industries and investigates the impact of the pandemic on the global and Turkish mining sectors. Furthermore, the study suggests numerous measures that should be adopted in mines to limit the spread of COVID-19 and conduct mining operations safely and efficiently. METHODS: An extensive literature review was conducted and relevant papers on the importance and benefits of the mining industry, the Turkish and global mining industry, and the impact of COVID-19 on the Turkish and global mining industry were studied. RESULTS: The COVID-19 crisis has deeply affected metal and mineral production and the economic sectors that depend on the mining industry for supplies. The most significant impacts caused by the COVID-19 pandemic on the global mining industry consist of the drastic decline in demand and production and the decrease in the prices of several commodities. As with any complex global situation, the mining industries of some countries were affected more than others by the COVID-19 crisis. The Turkish mining industry was to some extent affected by the COVID-19 crisis, but it quickly recovered. CONCLUSIONS: An efficient planning of operations and adopting effective measures and precautions enable limiting the spread of COVID-19 in quarries and mines.
Citation - WoS: 3
Citation - Scopus: 3
Investigation of Ash Removal From Fine Grain Coal-Water Suspension by Hydrophobic Flocculation Using Taguchi (l-16) Experimental Design
(Taylor & Francis Inc, 2022) Ağaçayak, Tevfik
In this study, it was aimed to remove ash from fine-grained coal-water suspensions and a series of hydrophobic flocculation experiments were performed using the Taguchi (L-16) experimental design to determine the experimental optimum conditions. Five different controllable process variables such as amount of sodium silicate, suspension pH, amount of waste vegetable oil, flock growth time, and precipitation time, which are effective in hydrophobic flocculation of coal, and four different levels of each variable were investigated. Optimum conditions were determined as amount of sodium silicate 1 mL, pH = 3, amount of waste vegetable oil 4 mL, flock growth time 7 min and precipitation time 1 min. According to the optimization results obtained, the high calorific value (5450 kcal/kg) clean coal with 15.46% ash content and 100% combustible recovery was obtained with 57.52% ash removal. In addition, the contributions of each factor to hydrophobic flocculation of coal were determined with one way variance analysis (ANOVA). The most influential factor was determined as the pH value with a contribution of 61.34%.
Citation - WoS: 4
Citation - Scopus: 4
Investigation of Climatic Conditions in Underground Coal Mining
(SPRINGER HEIDELBERG, 2020) Çınar, İbrahim; Özsen, Hakan
Mine workers in heavy and dangerous work are under several physical risk factors, for example temperature, humidity, noise, vibration, lighting and air velocity. Thermal comfort includes parameters such as air temperature, air humidity, air flow rate, radiant heat, metabolic rate and garment insulation. In this study, thermal comfort conditions were evaluated using thermal comfort indices defined as predicted mean vote (PMV) and predicted percentage dissatisfied (PPD) which were determined by measurements taken from an underground coal mine for approximately 100 days. Although the metabolic rate (light work) was kept at 2 met, it was found that predicted mean vote ranged between - 2.58 and 1.68. The predicted percentage dissatisfied index was found to reach 95%. According to the results, it can be seen that thermal comfort may have negative effects on occupational health and safety. The change in thermal comfort index values in the Soma Underground Coal Mine was investigated in detail and the reasons for the changes were determined. Furthermore, determining the optimal working environment for the mine workers was also an aim of this study.
Citation - WoS: 3
Citation - Scopus: 4
Investigation of Co-Combustion Characteristics of Olive Bagasse, Coal and Their Respective Blends by Thermogravimetric Analysis (tga)
(Taylor & Francis Inc, 2022) Ağaçayak, Tevfik
Co-combustion characteristic was investigated in detail to investigate the combustion of coal/olive bagasse and their different ratios blends (10%, 25%, 50%, and 75%) using the thermogravimetric analysis (TG) and the differential thermogravimetric analysis (DTG). Ignition and peak temperatures and other combustion characteristics for the samples were determined and correlated with the results obtained depending on the percentages of blends. As a results of the evaluation of all these parameters, it was thought that 25% olive bagasse and 75% coal blend were the most suitable value. In the final part of the work, the kinetic analysis of the samples was carried out by the Coats-Redfern method and the activation energies were determined. The activation energies of the coal/olive bagasse and their blends were assessed and compared. The calculated activation energy values for the combustion reactions of the samples ranged were found to be between 11.44 kJ/mol and 21.67 kJ/mol. As the blend percentage increased the olive bagasse showed a decreasing trend according to the ignition and peak temperature of the coal. It was determined that coal had more difficult combustible behavior than olive bagasse. In addition, a decrease in calorific values and an increase in comprehensive combustion index (CCI) value were observed as the percentage of olive bagasse blend increased.

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Browsing WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collections by Department "Fakülteler, Mühendislik ve Doğa Bilimleri Fakültesi, Maden Mühendisliği Bölümü"