Endo-b-1,4 xylanases (EC. 3.2.1.8) are typically produced as a mixture of different hydrolytic enzymes such as b-1,4-xylosidase (EC. 3.2.1.37) , a-Larabinofuranosidases (EC. 3.2.1.55), and feruloyl esterase (EC 3.1.1.73) that hydrolyze xylan molecule, which constitutes 20-30% of the weight of wood and agricultural wastes. Thus, xylan, a renewable biomass, can be utilized as a substrate for the preparation of many products such as fuels, solvents and pharmaceuticals. Besides, xylanolytic enzymes themselves are also used in food,feed, textile industries and pre-bleaching of kraft. In the first part of the study, xylanolytic systems of a soil isolate Bacillus pumilus SB-M13 and a thermophilic fungus Scytalidium thermophilum were investigated. Production rate and type of xylanolytic changed depending on the carbon source and the microorganism. However, xylanolytic enzyme production was found to be sequential, in synergy and under the control of carbon catabolite repression for both microorganisms. In the second part, B. pumilus SB-M13 b-1,4 xylanase was purified and biochemically characterized. The enzyme was stable at alkaline pHs and highest activity was observed at 60&deg / C and pH 7.5. Enzyme Km and kcat values were determined as 1.87 mg/ml and 43,000 U/mg, respectively. B. pumilus SB-M13 and S .thermophilum a-L-arabinofuranosidases were also purified and biochemically characterized. Although produced from a mesophilic microorganism, B. pumilus SB-M13 arabinofuranosidase was quite thermostable. Moreover, unlike other fungi, S. thermophilum produced alkaline stable arabinofuranosidases. Both enzymes were multimeric, alkaline stable and most active at 70&deg / C and pH 7.0. However, when compared to S. thermophilum, catalytic power of B. pumilus SB-M13 arabinofuranosidase was higher.

In presplit blasting operations airborne energy called air blast overpressure or impulsive sound is produced. The air blast induced by blasting may vary significantly at or around an open pit mine depending on several parameters such as the amount of charge detonated, the physical distance between the blast and the monitoring locations and the weather conditions. Therefore evaluation and assessment of noise condition at or around an open pit mine is necessary. The objective of this research study is to monitor and record the noise and to investigate and assess the noise conditions that will be induced from presplit blasting operations at Kisladag Gold Mine. In this research study, several parameters such as the amount of charge, the physical distance to the location of monitoring device or residential structures and the weather condition parameters such as wind direction, wind speed were recorded, analyzed and evaluated. It is observed that with increasing charge per delay air overpressure increases, whereas with increasing scaled distances it decreases. It is also understood that wind speed and the direction are effective in air overpressure propagation also, but this subject needs further investigation. It is concluded that according to the U.S. regulations there is no damage risk to the structures and no disturbance to the inhabitants at present. Due to the uncertainties in weather conditions, in order not to take any risks, the charge amount per delay should be kept at 35 kg or less for presplit blasting at the mine.

In this thesis 10x10 reconfigurable reflectarray is designed at 26.5 GHz where the change in the progressive phase shift between elements is obtained with RF MEMS switches in the transmission lines of unit elements composed of aperture coupled microstrip patch antenna (ACMPA). The reflectarray is illuminated by a horn antenna, and the reflected beam is designed to switch between broadside and 40&deg / by considering the position of the horn antenna with respect to the reflectarray. In the design, the transmission line analysis is applied for matching the ACMPA to the free space. The full wave simulation techniques in HFSS are discussed to obtain the phase design curve which is used in determining two sets of transmission line lengths for each element, one for the broadside and the other for switching to the 40&deg / at 26.5 GHz. The switching between two sets of transmission line lengths is sustained by inserting RF MEMS switches into the transmission lines in each element. Two types of RF MEMS switches, series and shunt configurations, are designed for the switching purpose in the reflectarray. The phase errors due to nonideal phase design curve and type of the RF MEMS switch are reduced. The possible mutual coupling effects of the bias lines used to actuate the RF MEMS switches are also eliminated by the proper design. To show the validity of the design procedure, a prototype of 20x20 reflectarray composed of ACMPA elements is designed at 25GHz and produced using Printed Circuit Board (PCB) technology. The measurement results of the prototype reflectarray show that the main beam can be directed to the 40&deg / as desired. The process flow for the production of the reconfigurable reflectarray is suggested in terms of integration of the wafer bonding step with the in-house standard surface micromachined RF MEMS process.

This thesis focuses on late Early Bronze Age metal objects from funeral context from the site Kalinkaya-Toptastepe, dated to the late 4th and 3rd millennium BCE. The site yielded a large number of metal objects from EBA necropolis of the southern slope of Toptastepe, offering an ideal closed assemblage for an archaeometrical analysis to reveal the metalworking technologies of an early small rural community of Central Anatolia. First archaeometrical analysis applied on these objects, however, revealed unexpectedly high amounts of Zinc, which turned out to be not an intentional alloy, but modern contamination due to the electrochemical cleaning, carried out in the 1970s. A second analysis has carried out after cleaning the metal objects with micro-sandblasting technique, to remove the artificial Zn contamination. The accumulated data provided us with important insights into the metal consumption and alloying traditions of a late EBA village community in Central Anatolia, showing the earliest conscious alloys were being applied in small hamlets of the EBA as well. It has been apparent that any pre-Iron Age metal object, revealing Zn in its chemical composition can not be considered as early brass, but clearly a result of modern, ill-advised cleaning application.

Started as an EOR technique to produce oil, injection of carbon dioxide which is essentially a greenhouse gas is becoming more and more important. Although there are a number of mathematical modeling studies, experimental studies are limited and most studies focus on injection into sandstone reservoirs as opposed to carbonate ones. This study presents the results of computerized tomography (CT) monitored laboratory experiments to characterize relevant chemical reactions associated with injection and storage of CO2 in carbonate formations. Porosity changes along the core plugs and the corresponding permeability changes are reported for varying CO2 injection rates, temperature and salt concentrations. CT monitored experiments are designed to model fast near well bore flow and slow reservoir flows. It was observed that either a permeability improvement or a permeability reduction can be obtained. The trend of change in rock properties is very case dependent because it is related to distribution of pores, brine composition and as well the thermodynamic conditions. As the salt concentration decreased the porosity and thus the permeability decrease was less pronounced. Calcite scaling is mainly influenced by orientation and horizontal flow resulted in larger calcite deposition compared to vertical flow. The duration of CO2 &ndash / rock contact and the amount of area contacted by CO2 seems to have a more pronounced effect compared to rate effect. The experiments were modeled using a multi-phase, non-isothermal commercial simulator where solution and deposition of calcite were considered by the means of chemical reactions. The calibrated model was then used to analyze field scale injections and to model the potential CO2 sequestration capacity of a hypothetical carbonate aquifer formation. It was observed that solubility and hydrodynamic storage of CO2 is larger compared to mineral trapping.

In this study, hazardous waste inventory for Turkey is developed based on wastes identified as hazardous in European Waste Catalogue and Regulation on Control of Hazardous Wastes, Annex 7 Necessity of such inventory arises from importance of acquiring information on the amount of hazardous wastes generated and on their countrywide distribution for a sound hazardous waste management system for Turkey. Hazardous waste inventory is constructed by using waste generation factors obtained from literature which are coefficients that relate production with environmental emissions. Whenever possible, direct information obtained from generators was utilized. Both absolute and minor entries are covered. It is estimated that 4,940,000 &ndash / 5,110,000 t/yr of hazardous wastes are being generated in Turkey. 1,790,000 &ndash / 2,252,000 t/yr of these are classified as absolute entries and 3,146,000 &ndash / 3,160,000 t/yr of hazardous wastes are minor entries. It is observed that highest generation occurs from mining and thermal processes which involve high amounts of minor entries. Beside these industries highest generation occurs from wood preservation. Per capita hazardous waste generation is estimated as 30 &ndash / 77 kg/capita/yr which is in accordance with per capita generation range of EU. Highest hazardous waste generation occurs from Marmara Region with 527,730 t/yr followed by Aegean (524,580 t/yr), Central Anatolia (481,820 t/yr), Black Sea Region (277,850 t/yr), Mediterranean (211,580 t/yr), Southeast Anatolia (58,290 t/yr) and Eastern Anatolia (36,520 t/yr) excluding minor entries from mining industry and thermal processes. The trends in hazardous waste generation and GDP from manufacturing industry show the same trend. Contribution of regions are in the same order both in hazardous waste generation and GDP.

This thesis work aims the ionic liquid pretreatment of peanut shells for co-production of glucose as fermentable sugar and lignin, considering a multi product perspective. The effects of ionic liquid type and pretreatment time period on the sugar and lignin yields were investigated, as the particle size and temperature parameters were determined in the preliminary studies. Peanut shells were pretreated at constant temperature, 150 oC, for 5, 15 and 30 minutes with 1-ethyl-3-methylimidazolium acetate and for 15, 30 and 60 minutes with 1-ethyl-3-methylimidazolium chloride. The pretreated peanut shells were then subjected to enzymatic hydrolysis in order to produce fermentable sugars, mostly, glucose. The solid residue obtained upon enzymatic hydrolysis was analyzed in terms of lignin quantity. 1-ethyl-3-methylimidazolium acetate pretreatment for 15 minutes resulted in the maximum reducing sugar and lignin yields / 28 g of reducing sugar and 20 g of solid residue with 70% lignin were obtained per 100 g of peanut shells. Higher pretreatment time resulted in lower yields. Moreover, no optimal time period for 1-ethyl-3- methylimidazolium chloride pretreatment was obtained, since reducing sugar and lignin yields increased as the time period increased. Also all reducing sugar and lignin yields were lower than that obtained with 1-ethyl-3-methylimidazolium acetate. Lignin obtained upon enzymatic hydrolysis of 1-ethyl-3-methylimidazolium acetate pretreated peanut shells were characterized by SEM, FTIR, TGA and XRD analyses, which also showed the morphological and structural effects of pretreatment and enzymatic hydrolysis on peanut shells / and used as concrete admixture, which increased the flow of the concrete by 6%.