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Soil specific surface area (SA) reflects the quantity and quality of the soil mineral and organic fractions. For soil samples that have similar clay mineral types, clay content and or organic carbon (OC) contents are good predictors of SA. However, the magnitude of the OC contribution to SA for different soil types is unclear, particularly since SA varies depending on which method or probe molecule is used to measure it. Consequently, we set out to (i) quantify the contribution of soil OC to total SA for soils with varying clay mineralogy, and (ii) assess the effect of probe molecule (EGME or H2O) and water sorption direction on the contribution of OC to the total SA. We utilized 330 soil samples (clay = 1 to 89 %; silt = 2 to 78 %; OC = 0.03 to 34.9 %) that were grouped according to clay mineralogy and OC content. The total SA was measured using EGME adsorption (SAE) and water adsorption and desorption (SAH2O). The contribution of OC to SA was examined using regression and partial correlation analyses that combined clay, silt, and OC as explanatory variables. Results showed that SAE values were strongly correlated to SAH2O, except for OC-rich soils where SAE was significantly lower than SAH2O. Apart from montmorillonite-rich samples, OC contribution to SAE was smaller than for SAH2O. Organic carbon had a positive contribution to desorption SAH2O for all sample groups, except for montmorillonite-rich samples; OC contribution was 7.5, 10.7, and 13.9 m2/g per %C for illite-rich, kaolinite-rich and OC-rich samples, respectively. There was no significant effect of water sorption direction on the OC contribution to SAH2O. Partial correlation analyses that accounted for clay and silt contents confirmed a negative contribution of OC to SAE or SAH2O for soil samples dominated by montmorillonite clay minerals. We can conclude that for the soil types investigated here (except montmorillonitic soils), OC has a positive contribution to total SA, and the magnitude of the contribution depends on the clay type.

The aim of this study was to evaluate the toxicity of Ethylene Glycol Monomethyl Ether (EGME) on fertility and early embryonic development to implantation, following oral gavage to Wistar rats. EGME, which is a known testicular toxicant, was administered to male rats for four weeks and to female rats for two weeks prior to mating at dose levels of 20, 40 and 80mg/kg orally, once daily. Dosing was continued in males until sacrifice (Day 43) and in females until day six of gestation. Females were sacrificed on Day 15 of gestation and examined for implantation sites, viable fetuses and ovarian corpora lutea. Males were evaluated for sperm parameters as well as organ weight and histopathology of the reproductive tissues. At the end of dosing, the 80 mg/ kg/day males had decreased weight and size of testes and epididymides which correlated with tubular atrophy of the testes and ductal atrophy plus reduced sperm in the epididymides. Testicular changes were less severe in the 40 mg/kg/day group, comprising Sertoli cell vacuolation, with degeneration and depletion of elongating spermatids and spermatid retention in the testes and lumenal cell debris in the epididymides. No testicular abnormalities were observed in the 20 mg/kg/ day males but cell debris was present in the epididymal lumen. There was a dose related decrease in total sperm count and sperm viability (≥20 mg/kg/day) and sperm motility (≥40 mg/kg/day). The fertility index in the EGME dosed groups showed a dose-related decline and the time taken for females to conceive was increased.

The increasing exploration and exploitation of hydrocarbon resources hosted by oil and gas shales demands the correct measurement of certain properties of sedimentary rocks rich in organic matter (OM). Two essential properties of OM-rich shales, the total specific surface area (TSSA) and cation exchange capacity (CEC), are primarily controlled by the rock’s clay mineral content (i.e. the type and quantity). This paper presents the limitations of two commonly used methods of measuring bulk-rock TSSA and CEC, ethylene glycol monoethyl ether (EGME) retention and visible light spectrometry of Co(III)-hexamine, in OM-rich rocks. The limitations were investigated using a suite of OM-rich shales and mudstones that vary in origin, age, clay mineral content, and thermal maturity. Ethylene glycol monoethyl ether reacted strongly with and was retained by natural OM, producing excess TSSA if calculated using commonly applied adsorption coefficients. Although the intensity of the reaction seems to depend on thermal maturity, OM in all the samples analyzed reacted with EGME to an extent that made TSSA values unreliable; therefore, EGME is not recommended for TSSA measurements on samples containing >3% OM. Some evidence indicated that drying at ⩾200°C may influence bulk-rock CEC values by altering OM in early mature rocks. In light of this evidence, drying at 110°C is recommended as a more suitable pretreatment for CEC measurements in OM-rich shales. When using visible light spectrometry for CEC determination, leachable sample components contributed to the absorbance of the measured wavelength (470 nm), decreasing the calculated bulk rock CEC value. A test of sample-derived excess absorbance with zero-absorbance solutions (i.e. NaCl) and the introduction of corrections to the CEC calculation are recommended.

The choice of the training system is a rather important decision for yield, fruit quality and profitability. There were dramatic changes in concepts for apple training in the last years. Centrifugal training system which was one of the innovations was developed in the beginning of the 2000’s in France. SolAxe training system forms the main part of this training system. The most innovative aspect of the Centrifugal training system is the artificial extinction technique. This technique is carried out more specifically in the center of the tree and on the underside of branches to remove potentially poor quality fruits. Artificial extinction improves light distribution within the tree canopy especially in colored-fruit varieties for which the light climate is particularly important. It also offers an alternative training method to reduce biennial bearing. In addition to canopy porosity created by artificial extinction, this training system can help reducing disease and harmful insects. In this study it is aimed to explain general rules of centrifugal training system., Terbiye sistemi seçimi, verim, meyve kalitesi ve karlılık açısından oldukça önemlidir. Son yıllarda elma ağaçlarının terbiyesinde büyük gelişmeler kaydedilmiştir. Bu yeniliklerden birisi olan merkezkaç terbiye sistemi, 2000’li yılların başında Fransa’da geliştirilmiştir. Bu sistemin temelini SolAxe terbiye sistemi oluşturmuştur. Bu sistemin getirdiği en büyük yenilik suni spur öldürme tekniğidir. Bu teknik daha çok ağacın iç kısmında ve düşük kalitede meyve oluşturma potansiyeline sahip olduğu için dalların alt taraflarında yapılmaktadır. Taç içerisine ışık girişini sağlayan suni spur öldürme, özellikle renklenme problemi olan çeşitlerde renklenmeyi artırmak açısından oldukça önemlidir. Bu terbiye tekniği aynı zamanda periyodisiteyi azaltmada bir alternatif sunmaktadır. Buna ilaveten suni olarak yaratılan taç boşluğu hastalık ve zararlı popülasyonunun azaltılmasına yardımcı olmaktadır. Bu çalışmada merkezkaç terbiye sisteminin genel prensiplerinin anlatılması amaçlanmıştır.

The choice of the training system is a rather important decision for yield, fruit quality and profitability. There were dramatic changes in concepts for apple training in the last years. Centrifugal training system which was one of the innovations was developed in the beginning of the 2000’s in France. SolAxe training system forms the main part of this training system. The most innovative aspect of the Centrifugal training system is the artificial extinction technique. This technique is carried out more specifically in the center of the tree and on the underside of branches to remove potentially poor quality fruits. Artificial extinction improves light distribution within the tree canopy especially in colored-fruit varieties for which the light climate is particularly important. It also offers an alternative training method to reduce biennial bearing. In addition to canopy porosity created by artificial extinction, this training system can help reducing disease and harmful insects. In this study it is aimed to explain general rules of centrifugal training system.; Terbiye sistemi seçimi, verim, meyve kalitesi ve karlılık açısından oldukça önemlidir. Son yıllarda elma ağaçlarının terbiyesinde büyük gelişmeler kaydedilmiştir. Bu yeniliklerden birisi olan merkezkaç terbiye sistemi, 2000’li yılların başında Fransa’da geliştirilmiştir. Bu sistemin temelini SolAxe terbiye sistemi oluşturmuştur. Bu sistemin getirdiği en büyük yenilik suni spur öldürme tekniğidir. Bu teknik daha çok ağacın iç kısmında ve düşük kalitede meyve oluşturma potansiyeline sahip olduğu için dalların alt taraflarında yapılmaktadır. Taç içerisine ışık girişini sağlayan suni spur öldürme, özellikle renklenme problemi olan çeşitlerde renklenmeyi artırmak açısından oldukça önemlidir. Bu terbiye tekniği aynı zamanda periyodisiteyi azaltmada bir alternatif sunmaktadır. Buna ilaveten suni olarak yaratılan taç boşluğu hastalık ve zararlı popülasyonunun azaltılmasına yardımcı olmaktadır. Bu çalışmada merkezkaç terbiye sisteminin genel prensiplerinin anlatılması amaçlanmıştır.

Terbiye sistemi seçimi, verim, meyve kalitesi ve karlılık açısından oldukça önemlidir. Son yıllarda elma ağaçlarının terbiyesinde büyük gelişmeler kaydedilmiştir. Bu yeniliklerden birisi olan merkezkaç terbiye sistemi, 2000’li yılların başında Fransa’da geliştirilmiştir. Bu sistemin temelini SolAxe terbiye sistemi oluşturmuştur. Bu sistemin getirdiği en büyük yenilik suni spur öldürme tekniğidir. Bu teknik daha çok ağacın iç kısmında ve düşük kalitede meyve oluşturma potansiyeline sahip olduğu için dalların alt taraflarında yapılmaktadır. Taç içerisine ışık girişini sağlayan suni spur öldürme, özellikle renklenme problemi olan çeşitlerde renklenmeyi artırmak açısından oldukça önemlidir. Bu terbiye tekniği aynı zamanda periyodisiteyi azaltmada bir alternatif sunmaktadır. Buna ilaveten suni olarak yaratılan taç boşluğu hastalık ve zararlı popülasyonunun azaltılmasına yardımcı olmaktadır. Bu çalışmada merkezkaç terbiye sisteminin genel prensiplerinin anlatılması amaçlanmıştır., The choice of the training system is a rather important decision for yield, fruit quality and profitability. There were dramatic changes in concepts for apple training in the last years. Centrifugal training system which was one of the innovations was developed in the beginning of the 2000’s in France. SolAxe training system forms the main part of this training system. The most innovative aspect of the Centrifugal training system is the artificial extinction technique. This technique is carried out more specifically in the center of the tree and on the underside of branches to remove potentially poor quality fruits. Artificial extinction improves light distribution within the tree canopy especially in colored-fruit varieties for which the light climate is particularly important. It also offers an alternative training method to reduce biennial bearing. In addition to canopy porosity created by artificial extinction, this training system can help reducing disease and harmful insects. In this study it is aimed to explain general rules of centrifugal training system.

The nature of component layers of mixed-layer illite-smectite and their possible evolution in the course of illitization have been debated since the 1960s. The present study is a new attempt to solve these problems, using samples collected from diverse geological formations around the world. Twenty three purified illite-smectites from bentonites and hydrothermal rocks, covering the complete range of expandability, were analyzed chemically, including ${\rm{NH}}_4^ + $ determination, and their structural formulae were calculated. The exchangeable cations (EXCH) were plotted vs. the fixed cations (FIX) yielding the following experimental regression: $${\rm{EXCH}} = - 0.43 \times {\rm{FIX}} + 0.41\;\;\left( {{{\rm{R}}^2} = 0.98} \right)$$ FIX and EXCH depend on the charge of the illite (Qi) and smectite (Qs) interlayers, and the fractions of these interlayers in the bulk clay leading to: $${\rm{EXCH}} = - {Q_{\rm{s}}}{\rm{/}}{Q_{\rm{i}}} \times {\rm{FIX}} + {Q_{\rm{s}}}$$ Analysis of these relations and independent measurements of the total specific surface area (TSSA) indicate that the layer charges of both types do not change in the course of illitization. The smectite layer charge is equal to 0.41 and the illite layer charge is equal to 0.95 per O10(OH)2. End-member illite has a well defined composition that is close to intermediate between muscovite and phengite, with fixed cations content greater than that specified in the AIPEA classification of layer silicates: $${\rm{FI}}{{\rm{X}}_{0.95}}\left( {{\rm{S}}{{\rm{i}}_{3.25}}{\rm{A}}{{\rm{l}}_{0.75}}} \right)\left( {{\rm{A}}{{\rm{l}}_{1.81}}{\rm{F}}{{\rm{e}}_{0.01}}{\rm{M}}{{\rm{g}}_{0.19}}} \right){{\rm{O}}_{10}}{\left( {{\rm{OH}}} \right)_2}$$ The established relationship allows the calculation of the mean number (N) of 2:1 layers in all fundamental particles and also the fraction of smectitic layers (fs) from FIX: $$N = {Q_{\rm{i}}}{\rm{/}}({Q_{\rm{i}}} - {\rm{FIX}})\;\;{f_{\rm{s}}} = ({Q_{\rm{i}}} - {\rm{FIX}}){\rm{/}}{Q_{\rm{i}}}$$ N and fs can be used to calculate TSSA, and all three parameters can also be calculated from cation exchange capacity and from X-ray diffraction peak positions, utilizing the regressions established here.

The total specific surface area (TSSA) and smectitic layer charge (Q) calculated from the structural formulae and unit-cell dimensions of 12 pure smectite samples were used as a reference in the design and evaluation of TSSA and Q measurement techniques based on cation exchange capacity (CEC), HO retention at 47% RH, and ethylene glycol monoethyl ether (EGME) retention. A thermogravimetric analysis-mass spectrometry (TGA-MS) technique was used to study the release of HO from smectite on heating, and to introduce a correction for HO remaining in the smectite after heating to 110°C, because the sample weight at this temperature has been used routinely as a reference in CEC and EGME sorption measurements. A temperature of 200°C was found to be the optimum reference for such measurements. A good agreement between Q from the structural formula and from CEC was obtained when this correction was applied. The TSSA of smectite was measured with similar accuracy (mean error of ±5-7%) by three techniques: (1) using mean HO coverage; (2) using mean EGME coverage; and (3) using a combination of HO coverage and CEC. A reduction of the mean error from 5-7% to 4% can be obtained by averaging these measurements, and a further reduction to 3% by introducing corrections for the dependence of HO and EGME coverage on layer charge. The study demonstrates that Ca-smectite samples at 47% RH have HO contents corresponding to 88-107% of the theoretical mass of a monolayer and offers an explanation of this variation.

Success in geotechnical analysis, design, and construction invariably requires that we have proper knowledge and understanding of (1) the strength, (2) the fluid flow properties, and (3) the stress-deformation behavior of the earth materials. These important engineering properties are primarily determined by the components and structure of a soil, which also dictate the soil's responses in an electromagnetic field. As a nondestructive technique, the electromagnetic property measurement offers a promising approach to characterize earth materials and identify the effects of changes in environments. However, despite many investigations in the last several decades, the relationship between the frequency-dependent electromagnetic properties of soils and their components and structure are still not well understood. Hence, estimation of engineering properties of a soil in a quantitative way from electromagnetic measurements can be uncertain. In this research several tasks have been accomplished: (1) Development of a physically based model that provides a means of investigating the coupled effects of important polarization mechanisms on soil electromagnetic properties, and a means of relating the electromagnetic properties of a soil to its fines content, clay mineralogy, anisotropy, degree of flocculation and pore fluid chemistry; (2) Proposal of a practically applicable method to determine the volumetric water content, specific surface area and pore fluid salt concentration simultaneously from the dielectric spectrum; (3) Deduction of the wide-frequency electromagnetic properties of a soil by measuring its responses to a step pulse voltage using time domain reflectometry (TDR); (4) Establishment of the relationships between the specific surface area and compressibility, residual shear strength and hydraulic conductivity. This study establishes a framework for quantifying soil engineering properties from their electromagnetic properties. If properly determined and interpreted, the electromagnetic properties can also provide insights into the causes of soil property changes over time and can be very useful in studying the effects of biological factors in geotechnical engineering, a field that may offer great potential for future advances. Ph. D.

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2007, Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2007, Gelişmiş helikopter rotor palaları genellikle kompozit malzemelerden üretilmektedirler ve yapılarında çeşitli hasarlara neden olabilecek yüksek derecede dinamik ve kararsız aerodinamik çevresel yüklerde çalışmaktadır. Bu yükleme şartlarına tekrarlı olarak maruz kalınması kompozit rotor pala yüzey kaplamalarında delaminasyon, çatlak vb. hasarlara neden olabilir. Bu tezin amacı, farklı kompozit rotor pala malzemelerinin, tasarımlarının ve imalat yöntemlerinin araştırılması ve döner kanat yüzey kaplamalarında yaygın olarak kullanılan [(0/±45/90)2]f yönlenmesinde dokunmuş karbon elyaf ve [(±45)8]f yönlenmesinde dokunmuş cam elyaf takviyeli epoksi matrisli kompozit levhaların çekme ve eğme yükleri altındaki davranışlarının incelenmesidir. Yüzey kaplama malzemesinin çekme ve eğmedeki mekanik özellikleri ASTM standartlarına uygun deneylerle elde edilmiştir. Sonuçlar, yüzey kaplama malzemesi olarak rijitlik, dayanım ve ağırlık bakımından karbon elyaflı dokuma malzemesinden seçilmesinin daha uygun olacağını göstermiştir. Ancak cam elyafa kıyasla çok daha gevrek yapıdaki karbon elyaf kompozit delaminasyon hasarına karşı çok daha duyarlı olduğundan imalat veya kullanımda çok daha titiz ve sıkı kontrol altında tutulmalıdır., Advanced helicopter rotor blades are generally made of composite materials. The helicopter rotor blades operate in a highly dynamic and unsteady aerodynamic environment leading to severe damage. Repeated exposure to severe repetitive loading conditions can induce damage such as delamination, cracking etc. on composite rotor blade skin. The objectives of this thesis are to investigate various composite rotor blade materials, designs and manufacturing methods and to determine the in-plane tensile and flexural properties of [(0/±45/90)2]f and [(±45)8]f woven carbon and glass fiber-epoxy matrix composites under tension and bending loads. Tension and flexural mechanical properties of the skin material were determined experimentally using the ASTM standards. The results showed that carbon woven fiber epoxy skin is more preferable due to its rigidity, strength and low density. However, with a significantly more brittle structure, the carbon fiber epoxy laminate is more sensitive to delamination, and thus tighter control measure are necessary during both manufacturing and operation., Yüksek Lisans, M.Sc.