Deposits In Turkey Research Articles

An investigation of the effects of moderator variables on the lower heating value estimation of lignite deposits in Turkey

An investigation of the effects of moderator variables on the lower heating value estimation of lignite deposits in Turkey

Mineralogical Transformation and Microstructure of the Killik Region Clays

Killik region (Mihalı¸c¸cık, Eski¸sehir, Turkey) is one of the most important loughlinite clay mineral deposits in Turkey and in the world. Along with loughlinite, analcime and dolomite minerals are also found in this deposit, which is not operable. Anorthoclase (94.61%) and quartz (4.94%) minerals (K2 sample) were obtained as the final product by applying Na ion exchange and thermal exchange processes to the minerals (K1 sample) taken from this deposit. In this study, XRD, Raman and infrared spectroscopies, and SEM techniques were used to characterize the phase structure of the K1 and K2 samples. As a result of this research, obtaining high purity anorthoclase mineral will encourage new research on new usage areas of anorthoclase mineral.

Investigation of Radiological and Chemical Contents of Bauxite Ore Extracted in Turkey.

In this study, which consists of two parts, the radiological and chemical content of bauxite ore was investigated. Gamma-ray spectrometry was used in the first part of the study to determine the activity concentrations of natural radionuclides in samples taken from bauxite deposits in Turkey. The measured activity concentrations of 226Ra, 232Th, and 40K varied from 12.1 ± 2.5 to 132.6 ± 11.4 Bq kg-1 with a mean of 78.4 ± 8.3 Bq kg-1, 6.5 ± 0.5 to 97.3 ± 9.9 Bq kg-1 with a mean of 64.5 ± 5.9 Bq kg-1, and 5.1 ± 0.0 to 356.4 ± 40.1 Bq kg-1 with a mean of 52.6 ± 5 Bq kg-1, respectively. The calculated mean radium equivalent activity value is 177.4 Bq kg-1, the mean gamma dose rate absorbed in the air is 78.8 nGy h-1, the mean corresponding annual effective dose value is 96.6 μSv y-1, and the mean lifetime risk of cancer is 3.85 × 10-4. The chemical content of the bauxite samples was determined in the second part of the study using X-ray fluorescence spectrometry (XRF). For which sectors in the industry the existing bauxite deposits in Turkey can be used was investigated based on this information.

Mapping carbonate-hosted Pb-Zn mineralization zones in Yahyali Province (Eastern Taurus - Turkey) using ASTER data

The first record of the carbonate-hosted Pb-Zn deposits in Turkey dates back to the Roman period. The carbonate-hosted Pb-Zn deposits in Turkey are economically important and found in the Aladağlar - Zamantı Province. Mineral exploration and geological mapping through the utilization of the traditional geological method still remain very challenging in many high terrains (High mountains). In this study, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) remote sensing data were used for mapping the carbonate-hosted Pb-Zn deposits in the Yahyali region of Turkey. The Band Ratio (BR), Least square fitting methοd (Ls–fit), Band Ratio Color Composite (BRCC), and Principal Cοmpοnent Analysis (PCA) were used tο map the Pb-Zn mineralization zone. The results of this investigation show the spatial distribution of Fe-Mg – OH/CO3, hydroxyl-bearing and iron oxide minerals. Field work and laboratory analysis were carried out to verify the occurrence of alteration zones and highly prospective locations and to confirm the availability of alteration and potential zones of carbonate-hosted Pb-Zn mineralization in the study area. Spatial correlation and distribution were observed between the previous geological map, active and abandoned mines, and the result obtained from the remote sensing data. Different techniques applied to the Aster data image in this study are recommended fοr carbonate-hosted Pb-Zn and lithological mapping in hostile terrains.

Cihanpaşa (Yozgat) bölgesinin güney kesimindeki manganez cevherleşmesinin jeokimyasal özellikleri ve kökeni

Late Cretaceous ophiolitic mélange complexes of the Izmir-Ankara-Erzincan Suture Zone (İAESZ) that is the remnant of the northern branch of the Neotethys Ocean host numerous manganese oxide deposits in Turkey. These deposits are observed within the red-violet radiolarian chert blocks belonging to mélange units. Of these mélange units, the Artova mélange is observed along the İAESZ in the northern part of the Kırşehir Massif, central Turkey, and is made up mainly of pelagic limestone, pillow basalt, radiolarian-chert blocks, and highly altered serpentinite. Mn-oxide mineralizations from Cihanpaşa (Yozgat, central Anatolia) region were analysed in order to determine their depositional conditions, paleo-redox signatures, origin and source. These mineralizations are composed mainly of an alternation of radiolarian cherts and mudstones that overlie altered pillow basalt in an overturned fold. Based on petrographic studies, the mineral paragenesis of the manganese oxide mineralizations is comprised predominantly of braunite, pyrolusite, pysilomelane and quartz. Geochemically, high Mn/Fe (60.2), low ΣREE (15.75 ppm) and Cu+Ni+Co (730 ppm), and a negative Ce anomaly and weakly negative Y/Y* anomaly (0.87) suggest that the Cihanpaşa manganese mineralizations formed in a submarine hydrothermal system. A negative Ce/Ce* anomaly (0.33), low Ceanom values (< − 0.54), and redox-sensitive tracers [V/(V + Ni) = 0.43, Ni/Co = 0.51, V/Mo = 6.15)] indicate that the manganese mineralization was formed by a hydrothermal system in an oxygenated marine sedimentary environment. Further, a weakly positive and negative Eu anomaly (0.84), high Lasn/Cesn (3.96), low Al/(Al + Fe) (0.34) and ΣREE/Fe (30.7x10-4) ratios highlighted that the Cihanpaşa manganese mineralizations were formed via impact of a low-T hydrothermal system, which is relatively close to the spreading ridge of the Izmir-Ankara-Erzincan Ocean.

Enhancement of pozzolanic activity of calcined clays by limestone powder addition

The influence of limestone powder addition on pozzolanic reactivity of calcined clays were investigated. Two clays containing kaolinite and halloysite in their compositions were obtained from different deposits in Turkey and physical, mineralogical, and morphological properties of the raw and calcined clay were characterized. Pozzolanic reactivity of calcined clays with and without limestone powder addition was then examined by means of lime consumption in lime-calcined clay pastes and their isothermal calorimetry as well as strength activity index test. Limestone powder addition enhanced the pozzolanic reactivity of calcined clays by increasing lime consumption and presenting higher heat of reaction released during pozzolanic activity. Limestone addition also provided benefits of reduced water requirement and increased strength activity for calcined clays. Improvements in pozzolanic reactivity and strength activity of calcined clays with limestone powder addition were attributed to nucleation effect provided by limestone particles and also formation of carboaluminate phases during pozzolanic reaction.

Formation and genesis of Paleozoic sediment-hosted barite deposits in Turkey

Most barite deposits in Turkey are sediment-hosted deposits which are located in different lithologies within passive margin sediments from the Paleozoic. The Şarkikaraağaç, Hüyük and Tordere deposits occur in the western part of the Tauride-Anatolide tectonic unit, whereas the Şekeroba and Önsen region deposits located in the eastern part of Turkey occur on both Arabian and Tauride-Anatolide microplates. While the former deposits occur as both concordant and discordant bodies within Early Paleozoic carbonates, the latter deposits are found as discordant, fracture filling and replacement-type ore bodies.O, D, S, Sr and Pb isotope studies were used to determine and correlate the formation conditions of these deposits. δ18OSMOW mean values of the Tordere barite deposit are slightly higher (mean 16.2‰) than the mean values for the Şekeroba (10.8‰) and Önsen (11.3‰) deposits. The δ18OSMOW (mean 15.83‰) and δDSMOW (mean −67‰) values obtained from fluid inclusions in quartz veins in the Şekeroba barite deposit correspond to metamorphic or deep circulation hydrothermal waters. Mean δ34 SCDT values from Şekeroba, Tordere and Önsen deposits are 31.7, 33.8 and 20.6‰, respectively, which are compatible with the early Paleozoic seawater, except for the Önsen deposit.87Sr/86Sr mean values for the barite deposits of Turkey are defined as follows (‰); Şekeroba: 0.713, Önsen: 0.711, and Tordere: 0.711, which are higher 87Sr/86Sr isotope ratios than Paleozoic seawater. The Pb isotope values in Şekeroba and Tordere deposits are similar and mean is 206Pb/204Pb = 18.28, 207Pb/204Pb = 15.67 and 208Pb/204Pb = 38.50. High radiogenic Sr and Pb isotope data from the deposits indicate that Ba was generated from thick Paleozoic clastics or the older crust beneath them.Sr, S, and O isotopes and the positive Gd anomaly in the barites are very similar to those of Paleozoic stratiform cold-seep barites. The primary stratiform-stratabound barite deposits, like Şarkikaraağaç-Hüyük deposit, could have formed either by cold seep or diagenetic processes at the sediment–seawater interface or within the sediment related to sulfate-methane boundary. Although there are similar Sr and Pb isotopic signatures between the western and eastern region deposits, the eastern region Şekeroba, Önsen and Tordere barite deposits show discordant ore geometry and highly radiogenic isotope values indicating that primary stratabound-stratiform barite was dissolved and remobilized along deep-seated fault zones during the Hercynian orogenesis and deposited in different Paleozoic lithologies related to cooling and/or increase in Eh.

Determinants of Dollarization of Savings in the Turkish Economy

This study aims to analyze the nature of the dollarization that takes place in the Turkish economy and to decompose the factors that have contributed to its increase in recent years. With this purpose, we first identify the events that have significantly affected the dollarization trend in Turkey using the Iterative Cumulative Sum of Squares (ICSS) and Markov Switching Dynamic Regression (MS-Dynamic) structural break models. Then, we proceed to analyze the relationship between the percentage of Forex deposits of the residents over total deposits of the residents and the TRY/USD exchange rate using the Johansen cointegration test. USD, EUR, and TRY interest rates are also added to the model as independent variables to account for the effects of the difference between exchange rates. Long-term and short-term effects are tested with the Vector Error Correction Model, and causality is tested using the Granger causality test. The results of the study indicate that speculative trading is not the cause of the dollarization of deposits in Turkey. Additionally, results suggest that the political events have a stronger influence over dollarization compared to economic events. Collectively, our findings suggest that domestic citizens dollarize their deposits with the motivation to protect against political ambiguity rather than economic volatility. The results of the study are in line with the literature in the sense that they support the claim that dollarization can be averted in the short run with an increase in interest rates.

Sea lilies of the genera Holocrinus, Tollmannicrinus, and Eckicrinus (order Holocrinida) from the Anisian (Middle Triassic) of Qingyan, south-western China

Disarticulated stem remains of the crinoid genera Holocrinus, Tollmannicrinus, and Eckicrinus of the order Holocrinida from Anisian (early Middle Triassic) strata of the eastern and north-eastern outskirts of Qingyan, Guizhou Province, south-western China, are described. Holocrinus qingyanensis sp. nov. (family Holocrinidae) occurs in early early to middle middle Anisian deposits. Tollmannicrinus leidapoensis sp. nov. is described from latest middle Anisian strata, and the genus Tollmannicrinus is placed in the new family Tollmannicrinidae of the order Holocrinida. Eckicrinus cf. radiatus (Schauroth) is documented from early late Anisian deposits; the family level assignment of Eckicrinus is unclear. Holocrinus qingyanensis and Eckicrinus cf. radiatus resemble contemporaneous congeneric species from Europe. Tollmannicrinus leidapoensis is related to the younger species Tollmannicrinus saklibelensis from late Ladinian to early Carnian deposits of Turkey.

Coal features and depositional environment of the Northern Karapınar–Ayrancı coal deposit (Konya, Central Turkey)

The Karapinar-Ayranci deposit is the most significant one among the recently explored coal deposits in Turkey. The aim of the present study was to determine maceral, mineralogical, and elemental compositions of coal samples picked up from one borehole (DK-7) drilled at the northern part of the deposit. The coal samples display moderate to high ash yield (average 38.7%, on dry basis), high volatile matter yield (average 33.9%, on dry basis), high total sulfur (average 6.7%, on dry basis) and low hydrogen contents (average 4.8%, dry basis). Huminite is dominant, and liptinite and inertinite appear at low concentrations. The bulk coal samples contain mainly quartz, clay minerals (mainly illite and chlorite), muscovite, feldspars, carbonates (calcite and aragonite), and rarely pyrite and gypsum/bassanite. The maceral and mineralogical compositions point to mesotrophic and rheotrophic conditions during peat accumulation; nevertheless, the inorganic intercalations show that peat formation was ceased several times. The petrographical and mineralogical compositions of coal seams in northern and eastern parts of the deposit could imply vegetation and water chemistry differences. The abundance of fossil shell-bearing layers in the studied samples could imply a slightly higher water table than this in the eastern part. In addition, higher telohuminite content might be related to a higher contribution of tree/bush peat-forming vegetation in the northern part; however, the lack of xylite-rich lithotype and the abundance of fluorinite-type resinite imply the predominance of shrubs on the palaeomire's surface. Overall, the precursor peat in the northern part of the deposit was accumulated under pure telmatic to limnotelmatic conditions, vegetation heterogeneity and ditches transporting inorganic material from the margins were developed on the surface of the Karapinar-Ayranci paleomire.

Rare earth element-bearing fluorite deposits of Turkey: An overview

Rare Earth Element (REE)-bearing fluorite deposits in Turkey occur in association with Cenozoic post-collisional alkaline-carbonatite systems and can be divided into three groups: (1) carbonatite-associated; (2) those associated with subalkaline to alkaline magmatic rocks of Cretaceous to Cenozoic age; and (3) those in sedimentary successions, typically in areas dominated by limestone. Some of these deposits show significant enrichment in the REE, especially the Kızılcaören deposit which has average REE grades of almost 30,000 ppm; others have very low REE contents but have potential fluorite resources.The homogenization temperature and salinity values of fluid inclusions in these deposits vary between 600 °C and 150 °C, and 10–65 wt% NaCl eq., respectively. The carbonatite-associated deposits have the highest bulk REE contents and are LREE-enriched. As a general feature, the REE contents of the fluorite deposits decrease with decreasing homogenization temperatures and salinity of the fluorite fluid inclusions. Fluorite ore chemistry indicates that a plot of Nb + Ta versus total REE differentiates the carbonatite- hosted from the alkali intrusive- hosted and carbonate- hosted deposits. Beyond the cooling and/or dilution of the fluids, REE and fluorite deposition was driven by changes in pH, instead of change in Eh, according to our geostatistical treatment. The chondrite-normalized rare earth element patterns of each group of deposits show some similar features, indicating that the REE in the fluorite are independent of their host lithology, but reflect the magmatic systems from which they were derived. Overall, the F-REE deposits of the Anatolides-Taurides in Turkey are considered to be largely related to the post-collisional magmatic systems, but with variable contributions of fluids from other sources.

Evaluation of the DNA damage in lymphocytes, sperm and buccal cells of workers under environmental and occupational boron exposure conditions

Industrial production and use of boron compounds have increased during the last decades, especially for the manufacture of borosilicate glass, fiberglass, metal alloys and flame retardants. This study was conducted in two districts of Balıkesir; Bandırma and Bigadic, which geographically belong to the Marmara Region of Turkey. Bandırma is the production and exportation zone for the produced boric acid and some borates and Bigadic has the largest B deposits in Turkey. 102 male workers who were occupationally exposed to boron from Bandırma and 110 workers who were occupationally and environmentally exposed to boron from Bigadic participated to our study. In this study the DNA damage in the sperm, blood and buccal cells of 212 males was evaluated by comet and micronucleus assays. No significant increase in the DNA damage in blood, sperm and buccal cells was observed in the residents exposed to boron both occupationally and environmentally (p = 0.861) for Comet test in the sperm samples, p = 0.116 for Comet test in the lymphocyte samples, p = 0.042 for micronucleus (MN) test, p = 0.955 for binucleated cells (BN), p = 1.486 for condensed chromatin (CC), p = 0.455 for karyorrhectic cells (KHC), p = 0.541 for karyolitic cells (KLY), p = 1.057 for pyknotic cells (PHC), p = 0.331 for nuclear bud (NBUD)). No correlations were seen between blood boron levels and tail intensity values of the sperm samples, lymphocyte samples, frequencies of MN, BN, KHC, KYL, PHC and NBUD. The results of this study came to the same conclusions of the previous studies that boron does not induce DNA damage even under extreme exposure conditions.

Efficacy of seven Turkish diatomaceous earths against Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae: Bruchninae) on stored chickpea: Presentation

In this study, insecticidal efficacy of seven different local diatomaceous earths (DE) obtained from different deposits in Turkey together with two commercial DEs, Silicosec® (Biofa AG- Germany) and Desect® (Ep Naturals- America) against Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae: Bruchninae) an important pest of stored chickpea at five different concentrations (100, 300, 500, 1000 and 1500 ppm) was evaluated. The local DEs were coded as BGN, BHN, AG2N, AC2N, CB2N, CCN, FB2N. Mortality of the adults was assessed after 1, 3, 5 and 7 days of exposure, and consequently progeny (F1) production on treated chickpeas was recorded 42 days later. The tests were carried out under laboratory conditions of 25±1 °C, 55±5 % R.H. in a dark place. The most effective DEs after 1 day of exposure were CCN, AG2N and BHN causing 75%, 59%, 58% mortalities, respectively at 1500 ppm concentration. Silicosec®, Desect®, BGN, AC2N, applied at 1500 ppm concentration achieved 98-100% mortality of C.maculatus after 7 days of exposure, showing similar high insecticidal efficacy. The CCN, BHN, AG2N and CB2N caused 97-99% reduction in progeny (F1) production. Generally, increasing concentration significantly reduced the progeny production. In conclusion, this study has shown that three Turkish DEs, namelyCCN, AG2N and BHN highly toxic to C. maculatus after 3 days of exposurein comparison with commercial DEs Silicosec® and Desect®. These local DEs could be used in the management of pests of stored chickpea.

Relationship between Rate of Returns on Foreign Exchange Islamic and Conventional Deposits in Turkey

The causal relationship between the rates of return on deposits of Islamic banks and deposits of conventional banks in an economy with dual banking systems is a significant area of study in the literature. While studying this causal relationship, vast majority of the existing studies consider domestic currency deposits. In this paper instead of domestic currency deposits, I consider foreign exchange currency deposits. By employing Toda-Yamamoto causality analysis, a causality relationship for all the maturity groups is found, but not for the 12-months maturity. For dollar accounts, the causality relationship between rate of returns of Islamic and Conventional banking is found to be two-way. For Euro accounts, this causality relationship is found to be one way, where the interest rate of conventional banks is Granger cause of profit share of Islamic banks.

Assessment of dynamic site response of the peat deposits at an industrial site (Turkey) and comparison with some seismic design codes

Peat is an organic soil type with properties of high compressibility and high water content. Peat deposits are often unsuitable for supporting structures of any kind due to their susceptibility to cause a number of geo-engineering problems, such as settlement, slope instability and soil amplification. There are peatlands in Turkey, although these are not so extensive as in other countries, such as Canada, where peatlands are very common. One of the peat deposits in Turkey is located close to the city of Kayseri (Central Anatolia), and industrial structures have been built on these deposits. This paper focuses on one part of a comprehensive research project conducted by the authors on various geo-engineering aspects of the peat deposits in this industrial site, with the main aims to investigate and assess some of the dynamic properties of the peat deposits in this area, to determine and assess their seismic site response and to compare them with the design spectra recommended in the current seismic codes of Turkey and Europe. In the study shear wave velocities of the peat deposits were determined with seismic measurements, and some dynamic properties of the peat were obtained from the resonant column and torsional shear tests. Then site response analyses were carried out and the results were compared with the design spectra recommended for loose-soft soils by the Turkish Seismic Design Codes and European Construction Design Codes. The comparisons suggest that the response spectra of the investigated peat deposits are greater than those recommended in the Turkish Seismic Codes and that at periods of > 0.3–0.5 s the peat will cause an increase in amplification. Although the response spectra of the peat tested show a better agreement with those recommended in the European codes, they show differences at periods of > 1 s.

Determination of 210Po and 210Pb depositions in lichen and soil samples collected from Köprübaşı-Manisa, Turkey

In this study, we aimed to determine the accumulations of 210Po and 210Pb in soil and lichen samples in Koprubasi. The Koprubasi district is home to the largest uranium deposits in Turkey. To date, there has been no study recorded in the literature related to 210Po and 210Pb depositions in lichens in Koprubasi. Six different lichen species (Cladonia convoluta, Parmelina tiliacea, Physcia stellaris, Pleurosticta acetabulum, Xanthoparmelia conspersa, and Xanthoria parietina) as well as soil samples were collected from seven sampling locations around Koprubasi. Lichens were used as biomonitors for 210Po and 210Pb deposition. The 210Po and 210Pb activity concentrations were measured in all the samples by alpha spectrometry. The activity concentrations in the lichen samples ranged from 64 to 577 Bq kg−1 with an average of 266 Bq kg−1 for 210Po and from 78 to 565 Bq kg−1 with an average of 333 Bq kg−1 for 210Pb. The activity ratios of 210Po/210Pb ranged from 0.80 to 1.99. In the lichen species, the mean 210Po activity values varied from 154 Bq kg−1 in Pleurosticta acetabulum to 390 Bq kg−1 in Xanthoparmelia conspersa. The range of the mean 210Pb activity was between 153 Bq kg−1 in Cladonia convoluta and 378 Bq kg−1 in Parmelina tiliacea. In the soil samples, 210Po and 210Pb activity concentrations were ranged from 14 to 1268 Bq kg−1 and from 19 to 1113 Bq kg−1, respectively. While the values of 210Po and 210Pb measured in the lichen samples are comparable with those of the literature, the results of 210Po and 210Pb in the soil taken from the uranium mine are higher than the results of the literature studies.

Uranyl phosphates and associated minerals in the Koprubasi (Manisa) uranium deposit, Turkey

The Koprubasi uranium deposit is the largest known uranium deposits in Turkey. Uranium mineralization is hosted in Neogene fluvial sediments that consist of predominantly sandstone and conglomerate interlayered with siltstone, claystone and mudstone. Sediments were primarily derived from metamorphic rocks adjacent to the basins of deposition, with some volcanic contribution in the form of tuffs. The sandstones and conglomerates are the most widespread sediments within the study area and host the majority of the U ore.X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) analysis were used to identify the ore and associated minerals. The uranium ore minerals of the host sedimentary rocks are torbernite, meta-torbernite and meta-autunite. These coexist with jarosite, various clays (chlorite/kaolinite, illite, and smectite), and Fe- and Mn-(hydr) oxides with minor titanium oxide. Additionally, quartz, feldspars and a minor amount of mica (muscovite and biotite) are the main primary minerals in the sedimentary rocks.The uranyl phosphates coat the surfaces of pebbles and some mineral grains, fill cracks, and are disseminated within the pores of the host sedimentary rocks. Uranyl phosphates are commonly associated with Fe-(hydr) oxides and clays, although some were observed in millimeter- or centimeter wide gaps within Koprubasi sediments. Oxides of manganese are also locally abundant and associated with uranyl phosphates.The uranyl phosphates in the sediments of the Koprubasi area most likely formed when oxidizing groundwater moved through the host rock. The common association of uranyl phosphates with Fe-(hydr) oxides and clays suggests that the precipitation of uranyl phosphate minerals is mainly due to adsorption of the uranyl and phosphate to the surface of Fe-(hydr) oxides and clays.

Lithium Extraction from Smectitic Clay Occurring in Lithium-bearing Boron Deposits in Turkey

Lithium Extraction from Smectitic Clay Occurring in Lithium-bearing Boron Deposits in Turkey

Bagging ensemble models for bank profitability: An emprical research on Turkish development and investment banks

The purpose of this study is to find the determinants of the profits for the Development and Investment Banks (IaDB) in Turkey. In Turkish Banking System, the main financial source of the banks is the deposits, which constitute almost%60 of the balance sheet. As being a sub-group of the banking system, IaDB are not allowed to accept deposits in Turkey, which changes the total structure of the profitability compared to other banks. Till today, none of the relevant research was concentrated on the profit structure of the IaDB neither in Turkey nor in any other countries. Such research would fill that unexpectedly disregarded yet highly important gap.Therefore, to address this gap, quarterly financial data (10 balance sheet ratios) of 13 banks in the period of 2002Q4-2014Q3 were utilized. As a profit measurement among all other available measures, Return on Equity was chosen as dependent variable as it was the most used one as well as many other researcher have preferred as well. This study investigates the potential usage of bagging (Bag), which is one of the most popular ensemble learning methods, in building ensemble models, is used to predict the determinants of Turkish IaDB profitability. Three well-known tree-based machine learning (ML) models (i.e., Decision Stump (DStump), Random Tree (RTree), Reduced Error Pruning Tree (REPTree)) are deployed as base learner. This empirical study indicates that bagging ensemble models (i.e., Bag-DStump, Bag-RTree, Bag-MLP and Bag-REPTree) are superior to their base learners and could improve the prediction accuracy of individual ML models (i.e., DStump, RTree, REPTree).

Investigation of Humate Extraction from Lignites

ABSTRACTThe present study investigated the extraction of humate from low-quality lignite samples acquired from Malkara and Yatagan coal deposits in Turkey. The experiments were conducted on finely ground representative coal samples at atmospheric pressure and room temperature. The samples were first leached with concentrated nitric acid for up to 72 hours and undissolved solids were removed by filtration. Potassium hydroxide was added to the leachate for alkalization in order to produce nitro-humic acid solution at different pH levels. Humic matter precipitation was achieved by addition of diluted nitric acid. The extraction products were investigated by proximate, Fourier Transform Infrared Spectroscopy (FTIR), and elemental analyses. The most important factors affecting humate extraction were found to be the consumption of nitric acid dosage for coal leaching, pH value of the leachate after potassium hydroxide addition, and mixing time. The promising results with over 80% humate extraction were achieved for the Yatagan lignites when the acid–coal consumption ratio was less than 1 mL concentrated nitric acid per 1 gram coal at a pH of 9 with mixing for 48 hours, while Malkara lignites reached 70% humate extraction with 72 hours of mixing under the same conditions.