Submarine and coastal karstic groundwater discharges along the southwestern Mediterranean coast of Turkey

A 120 km-long part of the southwestern coast of Turkey, with well-developed karst terrain in contact with the sea, has been investigated by systematic diving surveys to determine the submarine groundwater discharges (SGDs). The physical, chemical and isotopic data have been used to determine the rate of the fresh groundwater end member (FEM) and its temporal dynamics. About 150 SGDs have been detected by diving surveys employed mostly up to a depth of 30 m below sea level (bsl). Among those, 15 SGDs are in the form of coastal or submarine caves with entrances ranging between sea surface and 40 m bsl. The FEM contribution in SGDs ranges from a few percent to more than 80%. Stable isotope data suggest a range of mean recharge area elevations extending from the coast to more than 1,000 m inland. In many of the SGDs, the FEMs are characterized by tritium-based residence times ranging from recent to several decades. Hypothetical geochemical calculations of mixing between freshwater and seawater end members reveal that more than 45% of freshwater contribution is required for karst development in the SGDs. Models suggest a threshold pH of 7.6 or lower for the carbonate rock dissolution.     

Decolorization of Textile Azo‐metal Complex Dyes by a Halophilic Bacterium Isolated from Çamaltı Saltern in Turkey

The decolorization of some of azo‐metal complex dyes used in textile industry was investigated in this study. The halophilic prokaryotes isolated from a solar sea‐saltern (Çamalt?) in Turkey were screened for resistance to five commercial azo and mixture of azo‐metal complex dyes. Only one bacterium was found to be resistant against two of dyes, namely Lanaset Navy R and Lanaset Brown B. The bacterium was identified as Halobacillus sp. C‐22 according to 16S rRNA gene sequence analyses. Decolorization experiments were carried out at 120 mg/L concentration of both dyes, at room temperature, and with an acidic pH of 4.5. Lanaset Brown B was decolorized at a high adsorbance ratio (96.12%) at the 78th hour. However, Lanaset Navy R was rapidly decolorized in 10 min (46.67%) and showed the highest adsorbance ratio (60.66%) at the third hour. Freundlich and Langmuir equilibrium isotherm models were used to evaluate the adsorption of dyes and Freundlich isoterm was more suitable for biosorpsiyon of both azo dyes. The functional groups on Halobacillus sp. C‐22 for decolorization were characterized by FT‐IR. This is the first study to reveal potential of Halobacillus sp. for decolorization of textile azo‐metal complex dyes.     

Removal of Cu2+ and Pb2+ Ions Using CMC Based Thermoresponsive Nanocomposite Hydrogel

In this study, carboxymethylcellulose (CMC) based thermoresponsive nanocomposite hydrogel was synthesized for the removal of Cu²⁺ and Pb²⁺ ions from aqueous solutions. To prepare nanocomposite hydrogel, graft copolymerization of N‐isopropyl acrylamide (NIPAm) and acrylic acid (AA) onto CMC was carried out in Na‐montmorillonite (MMT)/water suspension media and ammonium persulfate (APS) used as initiator. The chemical structures of hydrogels were characterized by Fourier transform infrared (FT‐IR) and X‐ray diffraction spectroscopy (XRD). Lower critical solution temperature (LCST), pH responsivity, swelling, and deswelling properties of the hydrogels were also examined. In addition competitive and non‐competitive removal of Cu²⁺ and Pb²⁺ studies were carried out. According to heavy metal sorption studies results, removal capacities of nanocomposite hydrogel for both metal ions were found to be higher than those of pure hydrogel. The analyzed adsorption data showed that the adsorption process of Cu²⁺ and Pb²⁺ could be explained by pseudo‐second order kinetic model. Moreover, according to competitive sorption studies, it is found to be that both hydrogels are more selective to Cu²⁺ ion rather than Pb²⁺.     

Color Removal from Synthetic Textile Wastewater by Sono‐Fenton Process

In this study, the oxidative decolorization of C.I. reactive yellow 145 (RY 145) from synthetic textile wastewater including RY 145 and polyvinyl alcohol by Fenton and sono‐Fenton processes which are the combination of Fenton process with ultrasound has been carried out. The effects of some operating parameters which are the initial pH of the solution, the initial concentration of Fe²⁺, H₂O₂, and the dye, temperature, and agitation speed on the color and chemical oxygen demand (COD) removals have been investigated. The optimum conditions have been found as [Fe²⁺] = 20 mg/L, [H₂O₂] = 20 mg/L, pH 3 for Fenton process and [Fe²⁺] = 20 mg/L, [H₂O₂] = 15 mg/L, pH 3 for sono‐Fenton process by indirectly sonication at 35 kHz ultrasonic frequency and 80 W ultrasonic power. The color and COD removal efficiencies have been obtained as 91 and 47% by Fenton process, and 95 and 51% by sono‐Fenton processes, respectively. Kinetic studies have been performed for the decolorization of RY 145 under optimum conditions at room temperature. It has been determined that the decolorization has occurred rapidly by sono‐Fenton process, compared to Fenton process.     

Parameter Study on Prediction Methods for TBM Penetration Rate

Penetration rate prediction of Tunnel Boring Machine (TBM) is the first step to advance prediction process of mechanized tunnelling. In this research, influence of effective parameters on TBM penetration rate is investigated by sensitivity analysis of three main TBM performance prediction methods; Norwegian University of Science and Technology (NTNU), rock mass index (RMi) and Q_TBM. Based on these analyses, it is shown that applied thrust per disc and joint spacing in NTNU and RMi models have more influence on penetration rate. In Q_TBM model, Q value, applied thrust per disc and induced biaxial stress are more effective.     

Bench blasting design based on site-specific attenuation formula in a quarry

This research was performed on the quarry that will be opened to produce aggregates and rock filling material at Catalagzi region at Zonguldak province in Turkey. However, there are some structures which can be adversely affected by blasting at the quarry. These structures are a methane exploration drill hole and a house at the distances of 340 and 390 m, respectively. One of the main goals of this study is to perform a preliminary assessment of possible damage effect of ground vibrations induced by blasting on these structures by risk analysis based on ground vibration measurements. In order to propose a preliminary blast design models separately for aggregate and rock filling material production, six test shots with different maximum charge per delay were planned and fired at the quarry. In these shots, 90 events were recorded. To predict peak particle velocity (PPV), the relationship between the recorded peak particle velocities and scaled distances were investigated. During this investigation, the data pairs were statistically analyzed and a PPV prediction equation specific to this site with 95% prediction line were obtained. And also, this equation was used in the derivation of the practical blasting charts specific to this site as a practical way of predicting the peak particle velocity and maximum charge per delay for future blasting. A risk analysis was performed by using this equation. In the light of this analysis, preliminary blast design models were proposed to be used in this quarry for aggregate and rock filling material production.     

Adsorption Kinetic and Equilibrium Studies on Removal of Lead(II) onto Glutamic Acid/Sepiolite

In this study, a modified method was used to increase the adsorption of lead ions from aqueous solutions by using modified clay mineral on the laboratory scale. Adsorption experiments have been carried out on the use of both thermal activated sepiolite (TAS) and their glutamate/sepiolite modification (GS) as adsorbents. The experimental data was analyzed using adsorption kinetic models (pseudo first‐ and second‐order equations). The pseudo second‐order kinetic model fitted well to the kinetic data (R² ≥ 0.99). Then, the Freundlich and Langmuir models were applied to describe the uptake of Pb(II) on GS and the Langmuir isotherm model agrees well with the equilibrium experimental data (R² ≥ 0.97). The maximum adsorption capacity was observed to be 128.205 mg/g by GS according to the Langmuir equation. Desorption efficiency of the GS was studied by the batch method using EDTA, HCl, and HNO₃ solutions. Desorption of 69.18, 74.55, and 80% of Pb(II) from GS was achieved with 0.1 M EDTA, 0.1 M HCl, and 0.1 M HNO₃ solutions, respectively. FTIR analysis suggests the importance of functional groups such as amino, hydroxyl, and carboxyl during Pb(II) removal. SEM observations demonstrated that an important interaction at the lead‐modified sepiolite interface occurred during the adsorption process. In addition, the thermodynamic constants was calculated that the values of the Gibbs free energy (ΔG*), enthalpy (ΔH*), and entropy (ΔS*) of modification were 86.79 kJ/mol, ?18.91 kJ/mol, and ?354.70 J/mol/K, respectively. The negative value of ΔH* shows exothermic nature of adsorption.     

Evaluation and comparison of landslide susceptibility mapping methods: a case study for the Ulus district,Bartın,northern Turkey

The purpose of this study was to investigate the capabilities of different landslide susceptibility methods by comparing their results statistically and spatially to select the best method that portrays the susceptibility zones for the Ulus district of the Bart?n province (northern Turkey). Susceptibility maps based on spatial regression (SR), linear discriminant analysis (LDA), quadratic discriminant analysis (QDA), logistic regression (LR) method, and artificial neural network method (ANN) were generated, and the effect of each geomorphological parameter was determined. The landslide inventory map digitized from previous studies was used as a base map for landslide occurrence. All of the analyses were implemented with respect to landslides classified as rotational, active, and deeper than 5 m. Three different sets of data were used to produce nine explanatory variables (layers). The study area was divided into grids of 90 m × 90 m, and the ‘seed cell’ technique was applied to obtain statistically balanced population distribution over landslide inventory area. The constructed dataset was divided into two datasets as training and test. The initial assessment consisted of multicollinearity of explanatory variables. Empirical information entropy analysis was implemented to quantify the spatial distribution of the outcomes of these methods. Results of the analyses were validated by using success rate curve (SRC) and prediction rate curve (PRC) methods. Additionally, statistical and spatial comparisons of the results were performed to determine the most suitable susceptibility zonation method in this large-scale study area. In accordance with all these comparisons, it is concluded that ANN was the best method to represent landslide susceptibility throughout the study area with an acceptable processing time.     

Spatial Prediction of Lateral Variability of a Laterite-Type Bauxite Horizon Using Ancillary Ground-Penetrating Radar Data

Tropical laterite-type bauxite deposits often pose a unique challenge for resource modelling and mine planning due to the extreme lateral variability at the base of the bauxite ore unit within the regolith profile. An economically viable drilling grid is often rather sparse for traditional prediction techniques to precisely account for the lateral variability in the lower contact of a bauxite ore unit. However, ground-penetrating radar (GPR) offers an inexpensive and rapid method for delineating laterite profiles by acquiring fine-scale data from the ground. These numerous data (secondary variable) can be merged with sparsely spaced borehole data (primary variable) through various statistical and geostatistical techniques, provided that there is a linear relation between the primary and secondary variables. Four prediction techniques, including standard linear regression, simple kriging with varying local means, co-located cokriging and kriging with an external drift, were used in this study to incorporate exhaustive GPR data in predictive estimation the base of a bauxite ore unit within a lateritic bauxite deposit in Australia. Cross-validation was used to assess the performance of each technique. The most robust estimates are produced using ordinary co-located cokriging in accordance with the cross-validation analysis. Comparison of the estimates against the actual mine floor indicates that the inclusion of ancillary GPR data substantially improves the quality of the estimates representing the bauxite base surface.