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Öğe Arsenate Adsorption on Goethite Nanorods in the Presence of Geochemical Constituents(Springer Science and Business Media Deutschland GmbH, 2023) Alidokht, Leila; Karaca, Öznur; Shirzadeh, NasserThe present study describes the adsorption kinetics of arsenate (AsV) from solution by synthetic goethite nanorods (GN) in the presence of clay mineral, calcite, and leonardite-derived humic acid (HA). Batch experiments were performed at different pH values (5.5, 7, 8.5) to obtain the adsorption kinetics of AsV using 1 g L?1 GN, 120 mg L?1 HA, 4 g L?1 calcite, and 20 g L?1 kaolinite. Experiments containing calcite were only performed at pH values 7 and 8.5. The initial concentration of As was kept at 100 µM. Results showed that GN adsorbs near 50–70% As, depending on pH, and the reaction kinetics can be described by a pseudo-second-order model. Adsorption efficiency and the rate decreased with increasing alkalinity, indicating competition for sorption sites between AsV and OH? on GN. Calcite and HA showed no efficiency toward the adsorption of As within the studied time range. Slight As adsorption efficiency (? 14%) by kaolinite was observed at pH 5.5. In all studied pH values, the presence of HA, kaolinite, and calcite significantly inhibited the efficiency and rate of As removal by GN. Limited As adsorption in the presence of HA is probably due to the blockage of GN reactive surface sites by HA. In a system containing kaolinite and GN, the overall As removal rate was controlled by the lowest adsorbent. Interaction effects between kaolinite and calcite, calcite and HA, and kaolinite and HA on the removal of As were statistically insignificant. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd 2023.Öğe Bedrock Depth Calculation of Çanakkale (Turkey) Basin Using Rayleigh Ellipticity and Microgravity Survey(Universidad Nacional Autonoma de Mexico, 2023) Büyüksaraç, Aydın; Eyisüren, Onur; Bektaş, Özcan; Karaca, ÖznurIt is a well-known fact that the local ground effect plays an important role in the damage to structures during earthquakes. In order to define the soil-structure interaction correctly, the geometry of the tight and loose soil layers in the soil should be well known. In addition, the impedance contrast due to local ground effects can be deeper than the first 30 m, which is accepted as the engineering depth, and in this case, the Vs,30 parameter is disabled. For this reason, the location of engineering bedrock and seismic bedrock gains importance. The variation of shear wave velocity with depth is a key parameter for seismic field effect estimation. In addition, the separation of low-density layers close to the surface and higher-density bedrock can be easily done by the gravity method. Bedrock/seismic foundation levels were determined by using these two methods together for canakkale soils, which are known to have thick alluvial thickness and liquefaction problems. Microgravity measurements were made at 100 points and the anomalies obtained were modelled in three dimensions. In light of the data obtained from this study, it has been determined that the thickness of the loose basin unit in the study area is in the range of about 50-300 m. Ambient vibration was recorded with the help of a velocity seismometer at 146 points, and S velocity (Vs) profiles were obtained by using the inversion of the observed ellipticity curve. In addition, the velocity-depth change rate structure of the basin is defined depending on the Vs velocities on the 2D gravity model made along the two profiles that cut the basin in N-S and E-W directions. Along these profiles, the frequency range has been determined as 0.8-1.3 Hz in the deep parts of the Basin and 1.5-11.0 Hz in the shallow parts.Öğe Çerçi ve Murt Deresi (Fethiye-Muğla) Taşkın Duyarlılık Alanlarının CBS ile Çok Kriterli Karar Verme Analizi Kullanılarak Haritalanması(2021) Tüzgen, Güzin Akın; Karaca, ÖznurDünyada ve Türkiye’de en önemli doğal tehlikelerden biri olan taşkınlar doğal ya da\rinsan müdahalesi sonucu, şiddetine ve oluşum şartlarına bağlı olarak az veya çok\rolumsuz etki yaratarak afetlere yol açmaktadır. Bu çalışmada, Muğla İli Fethiye\ryerleşim alanı içerisinde yer alan Çerçi Deresi’nin taşkın analizi yapılarak, dere\ryatağının da bulunduğu çalışma alanı için taşkın duyarlılık haritası hazırlanmıştır.\rİnceleme alanı için Çerçi Deresi etrafında taşkına duyarlı alanların haritalanmasında\rbölgeye ait jeolojik, jeomorfolojik, sedimantolojik ve hidrolojik verilerden\ryararlanılmıştır. Çalışma alanı zeminlerinin fiziksel özellikleri incelenmiş ve ince kum,\rsilt ve kil boyutundaki sedimanların yoğunlukta olduğu görülmüştür. Alınan örnekler\rile yapılan zemin deneyleri neticesinde hakim zemin sınıfının orta plastisiteli inorganikkil (CL) olduğu belirlenmiştir. Taşkına duyarlı alanların haritalanmasında konumsal\ranaliz çalışmaları sırasında ArcGIS 10 programı ve alt modül olan Spatial Analysis\rmodülünden yararlanılmıştır. Çalışma alanının eğim, yükseklik, akarsuya yakınlık,\rjeoloji, arazi kullanımı ve bakı gibi kriterlere ait altlık haritaları oluşturulmuş ve ağırlıklı\rçakıştırma yöntemi kullanılarak taşkın duyarlılık analizi ArcGIS programı kullanılarak\rgerçekleştirilmiştir. Sonuçta, çalışma alanına ait taşkın duyarlılık haritası elde\redilmiştir. Oluşturulan bu duyarlılık haritasına göre çalışma alanının %17,64’ü taşkına\ryüksek duyarlı alanlar içerisinde yer almaktadır. Taşkına çok yüksek duyarlı alanlar\rda çalışma alanın güneybatısındaki Fethiye yerleşim merkezindeki alanları\riçermektedir.Öğe Combined effects of high voltage gradient and electrolyte conditioning on electrokinetic remediation for chromium (VI)-contaminated soils(Springer Science and Business Media Deutschland GmbH, 2023) Taneja, Sonam; Karaca, Öznur; Haritash, A. K.Disposal of chromium-containing industrial waste has led to soil contamination at dispersed locations around the globe. Considering the carcinogenic, non-biodegradable, and bioaccumulating nature of hexavalent chromium Cr (VI), it is per-tinent to treat the contaminated soils. Electrokinetic Remediation (EKR) is a promising technology to remediate metal-contaminated soils under the influence of an electric field. This study investigated the removal of Cr (VI) by EKR, enhanced with a combination of high voltage (50 V), electrolyte conditioning using EDTA (0.1 M), and type of electrode material. Under controlled conditions using distilled water, low voltage (20 V at 1 V/cm) resulted in 22% removal, while high volt-age (50 V at 2.5 V/cm) resulted in 55% removal of Cr (VI) in 10 h of treatment period. The removal was further enhanced to 77% by amending with ethylenediaminetetraacetic acid (EDTA 0.1 M) as an electrolyte at a high voltage gradient of 2.5 V/cm. Classifying the role of electrode (graphite and stainless steel), based on the removal efficiency and corrosion of electrodes, graphite resulted in higher removal compared to stainless steel but with a significantly higher corrosion effect. Characterization of soil after EKR experiments exhibited improved liquid and plastic limits, and insignificant difference in Total Organic Carbon (TOC) and other parameters related to soil health. Energy consumption and cost-estimation revealed that application of high voltage, along with conditioning of electrolyte with EDTA can significantly increase removal of Cr (VI) in short period of time in a cost-effective (0.8 US$/g) way, thereby can be applied for rapid treatment of large volumes of soil without affecting the properties of soil.Öğe Combined Use of Standard Penetration Test and Shear Wave Velocities in Liquefaction Analysis: Çanakkale Example(Springer Science and Business Media Deutschland GmbH, 2023) Eyisüren, Onur; Karaca, Öznur; Büyüksaraç, Aydın; Işık, ErcanIn order to investigate the liquefaction potential of the Çanakkale residential area, 151 boreholes, SPT, and 1027 classification tests were performed on disturbed samples, and 110 units of shear wave velocity (Vs) were determined by multi-channel analysis (MASW) of surface waves, and Vs values determined by underground water level information is used. Unlike previous studies, which were made using the simplified method based on SPT-N, liquefaction potential index (IL) and liquefaction risk index (IR) maps based on the standard penetration test (SPT) as well as Vs parameters were created separately for the Çanakkale settlement area. Very high IL and IR values were obtained in most of the city centers around Sarıçay. At the same time, analyses were repeated for different energy levels in order to investigate the effect of the energy coefficient, which is one of the SPT numbers of impact correction factors, on the analysis. As a result of all the analyses, it is thought that the energy level transferred in the SPT significantly affects the results, and since shear wave velocity (Vs) does not require such a correction, using SPT-N values as a reference in the analyses will reduce the negative effects that may arise from the uncertainties in field tests.Öğe Designing of Self-sustain Electrokinetic Experiment for Saline Soil Treatment(Springer Science and Business Media Deutschland GmbH, 2023) Karaca, Öznur; Cameselle, Claudio; Çalık, Ayten; Ulugergerli, Emin U.The lands stretching at the shorelines suffer from salinization which is one of the main environmental problems. Removing harmful salt contaminants requires an excessive amount of effort. The electrokinetic remediation (EKR) of soils away from urbanization is challenging since it requires a constant power supply. This research investigates the field scale effect of imposed electrical gradient (IEG) for the removal of salts from the soil with EKR using a solar panel-driven power supply. The testing soil was sampled in the Çanakkale-Dardanos Campus (CDC) area, in northwest Turkiye. The land in the CDC suffers from extreme saline water intrusion due to the excessive pumping of fresh water from multiple wells scattered in a relatively small area. The initial concentrations of salt ions were determined. Ca2+ showed the highest concentration (60,300 mg/kg) followed by Mg2+ (16,000 mg/kg), K+ (13,800 mg/kg), and Na+ ions (12,600 mg/kg). The most abundant anionic salt concentrations were Cl? (674 mg/kg) and SO4 2? (118 mg/kg). Lab-scale EKR studies showed that the EKR requires a minimum of 5-days to achieve satisfactory results. Therefore, we propose a mobile solar panel system and EKR as an innovative, sustainable, and environmentally friendly alternative to apply the EKR technology to saline soil. We will focus on designing the power supply system and fluid circulated electrodes. The results will be presented in due course. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd 2023.Öğe Fake and Synthetic Minerals; A Way to Sustain the Gem Supply(Springer-Verlag Singapore Pte Ltd, 2019) Çalık, Ayten; Karaca, Öznur; Yaşar, Cumali; Ulugergerli, Emin U.High demand for some rare gems creates pressure on the production line and some gems are consumed quickly in some countries. In order to sustain the gem supply to the most demanding markets, man-made minerals may be considered as an alternative to expensive genuine ones. Non-genuine precious and semiprecious stones can be found as enhanced, reproduced, and counterfeited gems. The former is extremely common among precious gems, while the last one is usually for semiprecious stones. Enhancement methods transform (or recycle) very low-quality (waste) gems into unique jewelry. Fabricated crystals are obtained (or recycled) from different or even irrelevant materials. The identification of such materials is getting harder due to continuous improvement in production technologies. Governing bodies have begun to issue regulations to their members so that misleading information given in retail can be reduced. In addition to limited regulation and enforcement, the buyers will also need some sort of education provided by trustworthy foundations such as reputable labs, mineral museums, and academic institutions. Although the internet provides a vast amount of information about fake minerals, most of which is also fictitious, especially, earth science-related museums should have a special duty in this regard and educate the public through hands-on experiments.Öğe Flood Susceptibility Mapping of Çerçi and Murt River (Fethiye-Muğla) Using Multi-Criteria Decision Analysis and GIS(Hacettepe Universitesi Yerbilmleri, 2021) Tüzgen, Güzin Akin; Karaca, ÖznurFloods are one of the most important natural hazards in the world and in Turkey, and depending on their severity and formation conditions, they can cause disasters by creating diverse negative impacts sources from natural effects or human intervention. In this study, flood susceptibility map was prepared by conducting flood analysis of Çerçi River in Fethiye District of Mugla Province, Turkey. While determining the flood susceptibility of Çerçi River, the geologic, geomorphologic, sedimentological, and hydrological data of the region were used. The physical properties of the study area were investigated, and it was observed that the fine sand, silt, and clay sediments were dominant. As a result of the soil tests performed with the samples, it was determined that the dominant soil class was medium plasticity inorganic clay (CL). For performing spatial analyses, the ArcGIS 10 software from ESRI Inc. and its module Spatial Analysis were used to map susceptible areas to floods. Different maps of the study area, such as slope, elevation, proximity to the rivers, geology, land use and aspect were employed in ArcGIS software using the weighted overlay method. As a result, the flood susceptibility map of the study area was obtained. Based on this susceptibility map, 17.64% of the study area is located in high susceptible areas. Very high susceptible areas include the parts of Fethiye District located in the southwest of the study area. © 2021, Hacettepe Universitesi Yerbilmleri. All rights reserved.Öğe Ganos fayı boyunca Geç Senozoyik yaşlı gerilme durumları, KB Türkiye(2013) Yıldız, Çınar Seray; Özden, Süha; Tutkun, Zeki Salih; Ateş, Özkan; Poyraz, Altuncu Selda; Yeşilyurt, Kapan Sevinç; Karaca, ÖznurSon defa 1912 yılında, magnitütü 7.3 (Ms) olan bir depremle hareket eden Ganos Fayı; K70°D doğrultulu sağ yanal doğrultu atımlı bir fay olarak, Gaziköy (Tekirdağ) ile Saros Körfezi arasında uzanmaktadır. Bu çalışmada; Ganos Fayı boyunca fay topluluklarının kinematik analizi, depremlerin odak mekanizması ters çözümleri ve uydu görüntüleri üzerinde uzaktan algılama çalışmalarıyla; Ganos Fayı ve bölgedeki Geç Senozoyik yaşlı gerilme durumları belirlenmiştir. Fay boyunca birbirleriyle uyumlu faylanma mekanizmalarıyla bir ana tektonik rejimin varlığı saptanmıştır. Bu faylanmalardan ilki, KB-GD yönlü sıkışma ve KD-GB yönlü açılma ekseni ile karakterize olan doğrultu atımlı faylanmadır. En büyük asal gerilme ekseni $(\\sigma_{1})$ 130°±16° ve en küçük asal gerilme ekseni $(\\sigma_{3})$ 53°±13° olarak belirlenmiş ve Rm oranı 0.49 olarak hesaplanmıştır. Bu faylanma ile uyumlu, eş zamanlı ve KD-GB doğrultulu açılma ekseni ile temsil edilen (?1 düşey yöndedir) lokal normal faylanmalar da belirlenmiştir. KD-GB yönlü açılmayla oluşan bu fayların kinematik analiz sonucunda en küçük asal gerilme ekseni $(\\sigma_{3})$ 28°±18° ile temsil edilmektedir. Ganos Fayı ve yakın çevresinde 2003-2010 yılları arasında meydana gelmiş (M?3.3) 12 adet depremin odak mekanizması ters çözümleri yapılmıştır. Bu çözümler üzerinden yapılan ortak ters çözüme göre; KB-GD yönlü sıkışma ve KD-GB yönlü açılma eksenleri ile karakterize olan doğrultu atımlı faylanmanın günümüzde de etkin olduğu görülmektedir. Günümüzde etkin tektonik rejim için hesaplanan, en büyük asal gerilme ekseni $(\\sigma_{1})$ ve en küçük asal gerilme ekseni $(\\sigma_{3})$ sırasıyla 276°±7° ve 6°±6° dir. Rm oranı da 0.44 olarak hesaplanmıştır. Gerek fayların kinematik analizi, gerekse deprem odak mekanizmalarının ters çözüm işlemi sonucunda elde edilen Rm oranlarının 0.5den küçük olması, Ganos Fayının geçmişte ve günümüzde transtansiyonel bir fay olarak çalıştığını göstermektedir. Uzaktan algılama yöntemiyle uydu görüntüleri üzerinde yapılan çizgisellik analizi çalışmalarında; 223 adet çizgisellik belirlenmiş ve bu çizgiselliklerin çoğunlukla Ganos Fayına parelel oldukları gözlenmiştir; Ganos Fayı; aktif sağ yanal doğrultu atımlı bir faydır ve Geç Pliyosenden beri çalışmaktadır.Öğe Hydrogeochemical Assessment of Groundwater for Drinking and Agricultural Use: A Case Study of Rural Areas of Alwar, Rajasthan(Springer, 2021) Aggarwal, Ankur; Soni, Jigyasa; Sharma, Khyati; Sapra, Mohnish; Karaca, ÖznurGroundwater contributes substantially to the development of arid and semi-arid regions around the globe. The present study integrates groundwater quality and its suitability for drinking and irrigation around Alwar city of Rajasthan state, where agriculture is the major land use. The application for drinking was assessed by comparing the observed value with prescribed standards of WHO. Groundwater was found suitable for drinking at most of the locations. The suitability of groundwater for irrigation was determined by calculating ion-based ratios and comparing them against the suggested ratios and indices for agricultural quality. Suitability for irrigation was assessed against electrical conductivity (EC), percentage sodium (%Na), residual Na2CO3 (RSC), per cent soluble sodium (SSP), sodium adsorption ratio (SAR), Mg hazard and permeability index (PI) etc., and the quality was compromised for EC, %Na and Mg Hz. Since the soil was sandy, the groundwater was found suitable for irrigation over long-term use, with the only problem of magnesium hazard. Based on the different ratios of anions and cations, silicate weathering was observed to be regulating groundwater chemistry, and the groundwater belonged to mixed CaMgCl and CaHCO3− type based on Piper’s classification and relative abundance of ions. Further, meteoric genesis classification showed that the groundwater in the study region had direct base exchange and shallow meteoric water percolation. Presence of kaolinite and quartz minerals in soil confirmed that silicate weathering is the major process controlling groundwater chemistry.Öğe Importance of Bedrock Depth Knowledge in Basins: Çanakkale (Dardanalles) Case History(Springer Science and Business Media Deutschland GmbH, 2022) Büyüksaraç, Aydın; Karaca, Öznur; Eyisüren, Onur; Bektaş, Özcan; Işık, ErcanIt is not correct to produce the necessary information for structuring, especially in environments such as Çanakkale, which exhibit a basin structure, without determining the bedrock or the strict ground conditions in bedrock. This approach is the basis of earthquake resistant building design. In this study, which was carried out to determine the bedrock/seismic foundation depth for the central settlement of Çanakkale and to define the basin structure to a certain extent, microgravity measurements were taken on a large scale, and the study area was modelled in three dimensions based on the obtained gravity data. By taking long-term microtremor measurements, one-dimensional depth-shear wave (Vs) velocity models were obtained using the Rayleigh ellipticity method. A depth map of the engineering bedrock was created, in which the velocity Vs reached to 2500 m/s. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.Öğe Liquefaction Potential Analysis and Mapping of Alluvium Soil: A Case Study in Nazilli-Aydın (West Turkey)(2020) Yürekli, Hayrullah; Karaca, ÖznurThe importance of urban planning for sustainable cities is indispensable. For this, the preparation ofgeotechnical maps, especially, comes to the agenda. Liquefaction susceptibility mapping is importantfor towns located in first-degree earthquake regions. This study investigated the susceptibility toliquefaction in a possible earthquake in Nazilli (Aydın) county considering geologic and geotechnicalstudies. In line with this, firstly drilling was completed at 110 points, with experiments performed onlocation and geotechnical properties determined in soil samples taken during this process. Generally, thecounty is founded on alluvial soils with groundwater very close to the surface. This situation makes itimportant to determine the liquefaction status of the town during a possible earthquake. The liquefactionpotential (FS) of the study area was determined with the simplified SPT based method and additionallythe liquefaction potential index (LPI) was calculated. Using this data and an ArcGIS program, the FSand LPI maps of the study area were prepared. According to the results obtained, the majority of thestudy area has very high liquefaction potential index.Öğe Treatment of Pb-contaminated soil by electrokinetics: Enhancements by varying voltage, chelant, and electrode material(Elsevier B.V., 2023) Taneja, Sonam; Karaca, Öznur; Haritash, Anil KumarThis work examines the removal of lead (Pb) from artificially contaminated soils (1000 mg/kg Pb) using the Electrokinetic Remediation (EKR) technique. Operating parameters, including periodic voltage gradient, electrolyte amendments with ethylenediaminetetraacetic acid (EDTA) and a non-ionic surfactant (Tween 80), and type of electrode material were investigated. Results indicated that a high voltage gradient (2.5 V/cm), in conjunction with EDTA as electrolyte, and stainless-steel electrodes favored the overall removal process. Pb removal by selected electrolytes was in order EDTA (65 %) > Distilled water (64.1 %) > Tween 80 (6.2 %). Visual Minteq v.3.1 software was employed to predict the chemical equilibrium of different chemical species of Pb against pH. Results confirmed that when EDTA was used as an electrolyte, the [Pb-EDTA]2− complex predominated over the Pb(OH)2 complex at an alkaline pH, resulting in more removal. Findings suggested that stainless steel was a better alternative to graphite with respect to removal efficiency and corrosion effect at the anode. Considering the maximum Pb removal with EDTA at higher voltage, the energy consumption was also maximum (78.3KWh/m3). Nevertheless, the economic evaluation suggested that the cost per gram removal of Pb was lowest in this experiment (8 US$/g Pb) and, thus, can be considered for practical applications to treat the Pb-contaminated soils.Öğe Using Granular Waste Tire as a Factor to Increase Shear Strength of Cohesionless Soils(2021) Aktürk, Koray; Karaca, ÖznurSoils used as foundation or structural materials in construction are considered to be weaker than rocks and problems such as bearing capacity, erosion, sliding, collapse, and liquefaction can be encountered. In such cases, since most soil problems are site specific, the soil properties should also be improved by appropriate techniques. Improvement methods applied to strengthen soils often cause financial burden. Recently, there are studies about the use of waste rubber tires, which pose an environmental risk during storage, as a reinforcement material for soils. The main purpose of this study is to examine the effect of poorly graded sand (SP) mixed with granular waste tires in different proportions (10%, 20%, 30%, 40% and 50%) on the shear strength of the sand. For this purpose, the physical (water content, specific weight, unit volume weight) and mechanical (shear strength) parameters of the mixtures were determined. According to the results of the research, the material with 100% sand content contributes to the shear strength by a certain proportion when compared to the mixed materials containing granular-sized waste rubber. According to the results of this research, the highest shear resistance value was observed in material with 20% tire content in waste rubber sand mixtures, while higher rates of tire addition provided lower results than 100% sand material. In addition, considering the issue in terms of environmental impact, a column test was carried out on the mixture containing 20% rubber-80% sand and no adverse effects of the pollutants were observed.Öğe World Multidisciplinary Earth Sciences Symposium - WMESS 2017(Institute of Physics Publishing, 2017) Drusa, Marian; Yilmaz, Isik; Marschalko, Marian; Török, Ibolya; Karaca, Öznur; Ferrero, Anna Maria[No abstract available]
