A technique was developed for analyzing and developing mechanical properties for porous geomaterials subjected to the high pressures encountered in penetration and blast-type loadings. A finite element (FE) code was developed to verify laboratory test results or to predict unavailable laboratory test data for porous media loaded to multikilobar stress levels. This FE program eliminates a deficiency in the process of analyzing and developing mechanical properties for porous geomaterials by furnishing an advanced analysis tool to the engineer providing properties to material modelers or ground shock calculators. The FE code simulates quasi-static, axisymmetric, laboratory mechanical property tests, i.e., the laboratory tests are analyzed as boundary value problems. The code calculates strains, total and effective stresses, and pore fluid pressures for fully- and partially-saturated porous media. The time dependent flow of the pore fluid is also calculated. An elastic-plastic strain-hardening cap model calculates the time-independent skeletal responses of the porous solids. This enables the code to model nonlinear irreversible stress-strain behavior and shear-induced volume changes. Fluid and solid compressibilities were incorporated into the code, and partially-saturated materials were simulated with a "homogenized" compressible pore fluid. Solutions for several verification problems are given as proof that the program works correctly, and numerical simulations of limestone behavior under drained and undrained boundary conditions are also presented. / Ph. D.

A study has been made of the enhancement of the mechanical strength of bricks fabricated from five Sri Lankan Quaternary and post-Quaternary brick clays with the objective of identifying and optimising those factors which control the quality and performance characteristics of fired clay products of this type. Mineralogical investigations have shown that the clays are predominantly kaolinitic. Of the accessory minerals, feldspars and gibbsite are the chief constituents. The experimental programme involved the development of feasible processing techniques for clay bodies, the establishment of optimum heat treatments for their firing, and the testing and evaluation of material properties of the fired products. The microstructures of fired materials have been characterized using optical and electron microscopical techniques, as well as X-ray diffraction, electron probe microanalysis and chemical analysis. A limited study was also made of the durability of laboratory fired specimens. Methods of strength enhancement included use of the reactions of phosphates with natural clays, use of mineralizers to induce mullitization and surface coating by an efflorescence process. A kinetic analysis based on the first order kinetics is proposed for the estimation of optimum firing conditions for kaolinitic clays. The study has shown that surface coating of bricks increases the load at the elastic limit by up to 30% and the ultimate failing load by 19% in the clays examined. The measured increases in modulus of rupture and modulus of elasticity are over 33% and 40% respectively. A fabrication technique which requires the incorporation of phosphates has been developed. This provides the possibility of lowering the peak temperature of firing to 500°C. Flexural strength increase of up to 60% over the normally fired unbonded specimens can be achieved using this technique. Relevant compatibility relations in the ternary system Si02- P205-AI203 at 500'C are proposed. The presence of an optimum amount of mineralizer in a clay body may alter its sintering characteristics resulting in an increase in modulus of rupture up to 55%. However, uncontrolled additions exceeding 4 wt% cause deleterious effects. Microstructural analysis provides evidence that liquid phase sintering, development of mullite, development of pores and bloating are the dominant strength determining features in these clays. An empirical equation correlating the functional relation between modulus of rupture, mullite content and porosity is proposed. Mechanisms of strength development are discussed in the light of these findings.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(農学) / 甲第19050号 / 農博第2128号 / 新制||農||1032 / 32001 / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 村上 章, 教授 藤原 正幸, 教授 澤田 純男 / 学位規則第4条第1項該当

of dissertation thesis Exogenic alteration of geomaterials with anomalous content of hazardous elements The research of waste materials from high temperature processes belongs to current issues solved in the field of modern environmental geochemistry. Current research has mainly been focused on fly ash and bottom ash coming from metallurgy, combustion and other industrial processes. In these wastes of different grain size, accumulation of hazardous elements occurs. These elements may be present in low concentrations in combusted coal or municipal solid waste or it may come from ore processing. Hazardous compounds are also intentionally added during the technological process (e.g. making of lead glass). Modern industrial plants are equipped with effective filtration systems, but this might not be in the past. In the Czech Republic and elsewhere in the world old environmental burdens are and will be addressed. Current modern filtration systems are never 100% efficient. Contamination of surrounding environment in a lesser extent can still occur. The production of lead glass (Bohemian Crystal) is based on the addition of lead compounds in the glass raw material. Additions of these substances providing a high refractive index of the finished product. Also compounds containing other hazardous elements...

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第19050号 / 農博第2128号 / 新制||農||1032(附属図書館) / 学位論文||H27||N4932(農学部図書室) / 32001 / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 村上 章, 教授 藤原 正幸, 教授 澤田 純男 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

In 2018 ESA and NASA plan to send the ExoMars rover to the Martian surface. This rover is planned to have a suite of analytical equipment that includes a Raman spectrometer. In this context, an evaluation of Raman spectroscopy as an analytical tool for interplanetary studies is investigated. The preparation techniques for appropriate inorganic and organic mixtures are interrogated. Methods are investigated to optimize the homogeneity of over 50 samples involving mineral phases; calcite, gypsum and goethite and selected organic biomolecular systems; anthracene, naphthalene and beta-carotene. From mixtures produced of these organic and inorganic materials differences between homogeneity of the samples is observed. Different mixing techniques are investigated to reduce this, however all the samples display variation on a micron scale. To resolve this issue a grid system of 9 points is implemented on solid samples and solutions are used to produce standards. The standards are devised using a range of instrument validation parameters for comparison between commercially available spectrometers and the prototype instrument. From these standards a prototype instrument is optimized for data acquisition and an evaluation procedure for instrument performance is established. The prototype Raman spectrometer is evaluated to match the specifications of the spectrometer on board ExoMars rover. A range of astrobiological relevant samples are interrogated; geological samples, biomarkers, cellular systems and bio-geological inclusions. From these samples detection of organics is observed to be only possible, with Raman spectroscopy where organics are localised in high concentrations, upon grinding and mixing geological inclusions Raman spectroscopy is unable to detect the organic components. / Appendices 3 and 4 are full text of the articles which are referenced in the text, but the published copy is not allowed to be displayed under copyright restrictions and are not included with this online thesis.

In 2018 ESA and NASA plan to send the ExoMars rover to the Martian surface. This rover is planned to have a suite of analytical equipment that includes a Raman spectrometer. In this context, an evaluation of Raman spectroscopy as an analytical tool for interplanetary studies is investigated. The preparation techniques for appropriate inorganic and organic mixtures are interrogated. Methods are investigated to optimize the homogeneity of over 50 samples involving mineral phases; calcite, gypsum and goethite and selected organic biomolecular systems; anthracene, naphthalene and beta-carotene. From mixtures produced of these organic and inorganic materials differences between homogeneity of the samples is observed. Different mixing techniques are investigated to reduce this, however all the samples display variation on a micron scale. To resolve this issue a grid system of 9 points is implemented on solid samples and solutions are used to produce standards. The standards are devised using a range of instrument validation parameters for comparison between commercially available spectrometers and the prototype instrument. From these standards a prototype instrument is optimized for data acquisition and an evaluation procedure for instrument performance is established. The prototype Raman spectrometer is evaluated to match the specifications of the spectrometer on board ExoMars rover. A range of astrobiological relevant samples are interrogated; geological samples, biomarkers, cellular systems and bio-geological inclusions. From these samples detection of organics is observed to be only possible, with Raman spectroscopy where organics are localised in high concentrations, upon grinding and mixing geological inclusions Raman spectroscopy is unable to detect the organic components.

An efficient methodology for separation of magnesium from different geomaterials was developed in order to determinate their isotopic composition. This methodology with 100% yield is suitable for high precision analysis of Mg isotopes by multi collector inductively coupled plasma mass spectrometry (MC-ICP-MS). Three separate stages of ion-exchange chromatography were carried out in ultra-trace laboratory equipped with laminar flowbox using cation exchange resin, AG50W-X12 and chemicals of ultrapure quality. Variations in samples 26 Mg/24 Mg and 25 Mg/24 Mg ratios are expressed as δ26 Mg and δ25 Mg units, which are deviations in parts per 103 from the same ratio in DSM3 Mg standard. The robustness of the technique was assessed by replicate analyses of magnesium standards Cambridge 1 versus DSM3. The long term repeatability of the Mg isotope ratio measurements of Cambridge 1 against DSM3 using this technique is -2.577 ± 0.10‰ on δ26 Mg and -1.328 ± 0.06‰ on δ25 Mg at 95% of confidence (2σ). Delta 26 Mg in five natural standard samples was measured in order to validate a quality of measurement in two different laboratories: Czech Geological Survey, Prague, Czech Republic and GFS Potsdam, Research centre for geoscientist, Potsdam, Germany. The results measured in this study (laboratory of CGS) are...

Nondestructive evaluation of civil structures is of increasing interest to utility owners. Several methods exist to evaluate different properties of concrete, pavement, cemented sands and others. UPVM is the most commonly used ultrasonic technique in civil structures due to its simplicity and ease of use. UPVM is fast and requires minimal skill from operators. It has been used for flaw detection, study of material contents, deduction of general deterioration, determination of elastic properties , measurement of strength, and others. In such applications, accurate measurements of velocity are essential for proper parameter evaluation and thus to increase the validity of conclusions obtained from measurements. Previous research in ultrasonic pulse velocity have found that UPVM are susceptible to specimen size, attenuation and frequency but no clear conclusions have yet to be made on the fundamental reason for the differences. This work seeks to identify the main factors responsible for velocity differences due to specimen size and measuring frequency in civil engineering materials. The effects are investigated by first performing numerical simulations of concrete specimens of varying sizes, and properties, excited by both a low (55 kHz) and high (850 kHz) frequency input source. Simulations are used to model wave propagation in cylindrical concrete specimen. Transducer sound fields are also numerically studied using known analytical solutions. An experimental program is conducted to study variations in UPVM in 12 mortar and 11 concrete cylindrical specimens of varying widths and heights caused by different measuring frequencies. Simulations are completed for 12 specimen of different dimensions having heights of 5,10,20 and 30 cm as well as diameters of 10, 20 and 30 cm. Both a low (f = 55 kHz) and high (f = 850 MHz) frequency input source are used on each specimen. Numerical simulations using low frequencies are made for both a damped and undamped series of specimen. Results from low frequency simulations of damped models indicate that wave attenuation can lead to significant errors in first arrivals when complex wave interference is present. Conditions for wave interference at the receiver location are studied and minimum size conditions for both height and width are derived. These conditions guarantee proper pulse separation for UPVM and are dependent on source size, and source pulse width. It is argued that with proper use these conditions will lead to accuracy of measurement better than one quarter of a period of the main excitation frequency when using a full waveform and a skilled operator. Finally, experiments are performed to assess differences in first arrivals between high and low frequency measurements. Readings are made on 11 mortar and 12 concrete specimen of different heights and widths. Experimentally significant time differences are observed between high and low frequency readings. It is found that differences in first arrivals will increase with specimen length but differences in velocity will decrease with length. Specimens 4 wavelengths in height are deemed sufficient to diminish surface effects to a minimum provided the specimens are healthy (e.g. no internal flaws). Any increase past 4 wavelengths is found to have negligible effects on measured velocity in healthy specimens.

Nondestructive evaluation of civil structures is of increasing interest to utility owners. Several methods exist to evaluate different properties of concrete, pavement, cemented sands and others. UPVM is the most commonly used ultrasonic technique in civil structures due to its simplicity and ease of use. UPVM is fast and requires minimal skill from operators. It has been used for flaw detection, study of material contents, deduction of general deterioration, determination of elastic properties , measurement of strength, and others. In such applications, accurate measurements of velocity are essential for proper parameter evaluation and thus to increase the validity of conclusions obtained from measurements. Previous research in ultrasonic pulse velocity have found that UPVM are susceptible to specimen size, attenuation and frequency but no clear conclusions have yet to be made on the fundamental reason for the differences. This work seeks to identify the main factors responsible for velocity differences due to specimen size and measuring frequency in civil engineering materials. The effects are investigated by first performing numerical simulations of concrete specimens of varying sizes, and properties, excited by both a low (55 kHz) and high (850 kHz) frequency input source. Simulations are used to model wave propagation in cylindrical concrete specimen. Transducer sound fields are also numerically studied using known analytical solutions. An experimental program is conducted to study variations in UPVM in 12 mortar and 11 concrete cylindrical specimens of varying widths and heights caused by different measuring frequencies. Simulations are completed for 12 specimen of different dimensions having heights of 5,10,20 and 30 cm as well as diameters of 10, 20 and 30 cm. Both a low (f = 55 kHz) and high (f = 850 MHz) frequency input source are used on each specimen. Numerical simulations using low frequencies are made for both a damped and undamped series of specimen. Results from low frequency simulations of damped models indicate that wave attenuation can lead to significant errors in first arrivals when complex wave interference is present. Conditions for wave interference at the receiver location are studied and minimum size conditions for both height and width are derived. These conditions guarantee proper pulse separation for UPVM and are dependent on source size, and source pulse width. It is argued that with proper use these conditions will lead to accuracy of measurement better than one quarter of a period of the main excitation frequency when using a full waveform and a skilled operator. Finally, experiments are performed to assess differences in first arrivals between high and low frequency measurements. Readings are made on 11 mortar and 12 concrete specimen of different heights and widths. Experimentally significant time differences are observed between high and low frequency readings. It is found that differences in first arrivals will increase with specimen length but differences in velocity will decrease with length. Specimens 4 wavelengths in height are deemed sufficient to diminish surface effects to a minimum provided the specimens are healthy (e.g. no internal flaws). Any increase past 4 wavelengths is found to have negligible effects on measured velocity in healthy specimens.