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The ageing of high density polyethylene geomembrane (GM) liners used to minimize advection and diffusion of contaminants in municipal solid waste landfill leachate and in hydrocarbon spills to the environment is examined. The evaluation of the ageing of GMs used in landfills involved four components. First, a laboratory-accelerated ageing investigation of a GM exposed to air, water and leachate at elevated temperatures. Service life of a GM (Stage I: Antioxidant depletion, Stage II: Induction, and Stage III: Polymer degradation) is examined. The results demonstrate the critical role of antioxidants in protecting against oxidative degradation. The service life of the GM is predicted. Second, a study was conducted to provide an estimate of Stage I for a GM in a composite liner. The results indicated that immersion tests are too severe and the service life is substantially greater for a GM in composite liner than implied by leachate immersion tests. Third, a comparison of ageing with three different “protection” layers between the GM and overlying gravel and leachate is reported. A slower antioxidant depletion rate is observed when geotextile-geosynthetic clay liner and geotextile-sand-geotextile are applied than with a typical geotextile alone. This could be partially attributed to the attenuation of leachate constituents by the protection layer as well as the buildup of antioxidant concentration on either side of GM thereby reducing the concentration gradient and outward diffusive flux of antioxidants. Fourth, diffusion modelling is used to evaluate the results from immersion and composite liner simulation tests. Diffusion modelling provided a means for predicting the performance of the GMs in conditions other than the typical test conditions. The evaluation of the ageing of GM used in barrier system for hydrocarbon involved two components. First, untreated and fluorinated GMs immersed in jet fuel were tested. Results show that antioxidants depleted at slower rate from fluorinated GM than untreated GM. This suggested a significant beneficial effect of fluorination. Antioxidant depletion time is predicted at field temperatures. Second, the time dependant change in GM samples used at jet fuel containment site constructed in 2001 is reported. The GM is shown to be performing very well. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2009-01-14 10:46:31.089

Disertacijoje siekiama išnagrinėti Rusijos ir Baltarusijos karinio aljanso formavimąsi ir patvarumą veikiant išoriniams bei vidiniams veiksniams. Vieną darbo dalį sudaro aljanso formavimosi teorijos, karinė integracija ir patvarumo teorinis tyrimas. Disertacija pasitelkia aljansų teorijas, jas sintezuoja ir išskiria priežastinius veiksnius, kurie daro įtaką aljanso patvarumui. Didelis dėmesys skiriamas karinei integracijai, kuri padeda nustatyti aljanso formavimosi etapus ir išskiria patvarumo kriterijus. Antrojoje tyrimo dalyje analizuojamas dabartinis Rusijos ir Baltarusijos karinio aljanso plėtros dinamiškumas, potencialas ir struktūra, t. y. pasinaudojant karinės integracijos modeliu tiriama, kas, kaip ir kokiomis priemonėmis buvo pasiekta. Trečiojoje disertacijos dalyje įvertinamas veiksnių poveikis aljanso patvarumui ir raidai. Tyrime naudojami tradiciniai socialinių mokslų metodai, kurie padeda apibendrinti ir paaiškinti veiksnius ir susieja tyrimo dalis su išvadomis. Daroma išvada, kad karinių aljansų integracija yra laipsniškas procesas, o integracijos etapų modelis parodo valstybių karinio bendradarbiavimo patvarumą ir jų preferencijas. Pagal karinės integracijos modelį atlikus Rusijos ir Baltarusijos karinės sąjungos analizę, pabrėžiama, kad ši sąjunga yra aukščiausiame karinės integracijos etape. Aljanso dezintegracija mažai tikėtina, nes valstybių karinės pajėgos yra pasiekusios aukštą sąveikumo laipsnį ir sukurtos struktūros iš dalies prisideda prie... [toliau žr. visą tekstą] / Dissertation seeks to analyze the formation and durability of military alliance between Russia and Belarus by employing internal and external factors. One part of the research includes alliance theories, military integration and theoretical research of durability. Dissertation employs a number of causal factors deriving from alliance theories and points out those that influence the durability. A great importance is attached to the military integration which specifies the stages of alliance formation and indicates the criterions of durability. In the second part of the research the military alliance between Russia and Belarus is analyzed, placing an heavy emphasis on its structure, capabilities and potentiality. In other words, in using military integration models it is analyzed what, how and with what means the current alliance has achieved. The third part is devoted to the influence of the factors on the alliance durability and its development. Traditional social methods are used in the research in order to explain the factors and link up the research with outcomes. The research concludes that the military integration of alliances is an incremental process and its model demonstrates inter-state military cooperation and preferences. Having analyzed Russian-Belarusian case in accordance to the military integration model, it was concluded that this union has reached the highest military integration stage. The disintegration is unlikely because the military forces of Russia and... [to full text]

Dissertation seeks to analyze the formation and durability of military alliance between Russia and Belarus by employing internal and external factors. One part of the research includes alliance theories, military integration and theoretical research of durability. Dissertation employs a number of causal factors deriving from alliance theories and points out those that influence the durability. A great importance is attached to the military integration which specifies the stages of alliance formation and indicates the criterions of durability. In the second part of the research the military alliance between Russia and Belarus is analyzed, placing an heavy emphasis on its structure, capabilities and potentiality. In other words, in using military integration models it is analyzed what, how and with what means the current alliance has achieved. The third part is devoted to the influence of the factors on the alliance durability and its development. Traditional social methods are used in the research in order to explain the factors and link up the research with outcomes. The research concludes that the military integration of alliances is an incremental process and its model demonstrates inter-state military cooperation and preferences. Having analyzed Russian-Belarusian case in accordance to the military integration model, it was concluded that this union has reached the highest military integration stage. The disintegration is unlikely because the military forces of Russia and... [to full text] / Disertacijoje siekiama išnagrinėti Rusijos ir Baltarusijos karinio aljanso formavimąsi ir patvarumą veikiant išoriniams bei vidiniams veiksniams. Vieną darbo dalį sudaro aljanso formavimosi teorijos, karinė integracija ir patvarumo teorinis tyrimas. Disertacija pasitelkia aljansų teorijas, jas sintezuoja ir išskiria priežastinius veiksnius, kurie daro įtaką aljanso patvarumui. Didelis dėmesys skiriamas karinei integracijai, kuri padeda nustatyti aljanso formavimosi etapus ir išskiria patvarumo kriterijus. Antrojoje tyrimo dalyje analizuojamas dabartinis Rusijos ir Baltarusijos karinio aljanso plėtros dinamiškumas, potencialas ir struktūra, t. y. pasinaudojant karinės integracijos modeliu tiriama, kas, kaip ir kokiomis priemonėmis buvo pasiekta. Trečiojoje disertacijos dalyje įvertinamas veiksnių poveikis aljanso patvarumui ir raidai. Tyrime naudojami tradiciniai socialinių mokslų metodai, kurie padeda apibendrinti ir paaiškinti veiksnius ir susieja tyrimo dalis su išvadomis. Daroma išvada, kad karinių aljansų integracija yra laipsniškas procesas, o integracijos etapų modelis parodo valstybių karinio bendradarbiavimo patvarumą ir jų preferencijas. Pagal karinės integracijos modelį atlikus Rusijos ir Baltarusijos karinės sąjungos analizę, pabrėžiama, kad ši sąjunga yra aukščiausiame karinės integracijos etape. Aljanso dezintegracija mažai tikėtina, nes valstybių karinės pajėgos yra pasiekusios aukštą sąveikumo laipsnį ir sukurtos struktūros iš dalies prisideda prie integracijos... [toliau žr. visą tekstą]

Industry equipment such as pressure vessels, mining equipment, heat exchang-ers, steam generators and other structures are provided with bolted closures for the purpose of in-service inspection and maintenance of internal components. Threaded connections often experience variable cyclic loads due to temperature, inner pressure and variation in the deformation of connection fittings. Often, studs and screws are not only affected by an axial load, but also by bending moments. More sophisticated high-cycle and low-cycle durability calculation meth-odologies have been already developed for threaded connections experiencing cyclic axial loads, and in these methodologies the distribution of axial load among turns is assessed quantitatively. The quantitative data of load distribu-tion in the thread enables a more accurate assessment of the influence of the constructional design particularities (connection length, material, nut and turn’s form) and the deformation stages of the connection element. These durability calculation methodologies are not applied for threaded connections that are cyclically bent, as the analytical models that are suitable for practical application in the load distribution of the turns have not been cre-ated for bent threaded connections. In this field, no models have been created to be calculated by the BE method. As the threaded connection is a complex node consisting of deformed el-ements, the load distribution among turns is influenced by the... [to full text] / Srieginės jungtys dažnai patiria ciklinių lenkimo apkrovų dėl temperatū-ros, vidaus slėgio ir jungiamųjų detalių deformacijų kitimo. Srieginėms jung-tims, kurios patiria ašinių ciklinių apkrovų jau yra sukurtos modernesnės daugiaciklio ir mažaciklio ilgaamžiškumo skaičiavimo metodikos, kuriomis detaliai kiekybiškai įvertinamas ašinės apkrovos pasiskirstymas tarp vijų. Ap-krovos pasiskirstymo sriegyje kiekybiniai duomenys leidžia detaliau ir tiksliau įvertinti konstrukcijos ypatumų (jungties ilgio, medžiagos, veržlės ir vijų for-mos) ir jungties elementų deformavimo stadijų įtaką. Tokios ilgaamžiškumo skaičiavimo metodikos cikliškai lenkiamoms srieginėms jungtims netaikomos, nes lenkiamoms srieginėms jungtims nėra sukurtų apkrovos pasiskirstymo vijose analitinių modelių, tinkamų praktiniam naudojimui. Šioje srityje taip pat nėra sukurtų ir modelių, kurie skaičiuojami baigtinių elementų metodu. Kadangi srieginė jungtis yra kompleksinis mazgas, kurį sudaro deformuo-jami elementai, tai apkrovos pasiskirstymą tarp vijų lemia jungties elementų deformacijų ir poslinkių suderinamumas. Matematiškai aprašant jungties de-formuotą būvį, reikalingi teoriniai ir eksperimentiniai duomenys, kurie atspin-dėtų jungties elementų deformavimo specifinius ypatumus, pasireiškiančius veikiant lenkimui. Disertacijoje siekiama sukurti cikliškai lenkiamų srieginių jungčių apkro-vos pasiskirstymo sriegyje skaičiavimo metodą ir pritaikyti jį mažacikliam ilga-amžiškumui skaičiuoti.

As an abundant sedimentary rock, shale is widely used as construction material around the world. However, shale is a fissile and laminated material and is therefore subject to deterioration due to environmental and chemical forces (i.e., weathering), which is possible to cause high maintenance cost on associated structures and failures of earth slopes and embankments. However, currently, there is lack of efficient method to monitor the weathering process of shale. This thesis uses several shale samples collected from the commonwealth of Kentucky to study the deformation and shear behaviors of weathered compacted shale. A new electrical approach was developed to access the deformation behavior of shale. The long term deformation behaviors, such as collapse and swell can be predicted from specific electrical parameters. The critical state theory was used to describe the shear behavior of weathered compacted shale. Some findings observed by previous researchers were confirmed, and new empirical equations were provided to estimate the shear strength parameters of weathered compacted shale.

Porous zeolite, carbon and aluminophosphate powders have been colloidally assembled and post-processed in the form of monoliths, flexible free standing films and coatings for gas separation and odor removal. Zeolite 13X monoliths with macroporosites up to 50 vol% and a high CO2 uptake were prepared by colloidal processing and sacrificial templating. The durability of silicalite-I supports produced in a binder-free form by pulsed current processing (PCP) were compared with silicalite-I supports produced using clay-binders and conventional thermal treatment. Long-term acid and alkali treatment of the silicalite-I substrates resulted in removal of the clay binder and broadened the size-distribution of the interparticle macropores. Furthermore, strong discs of hydrothermally treated beer waste (HTC-BW) were produced by PCP and the discs were activated by physical activation in CO2 at high temperatures. The activated carbon discs showed high strength up to 7.2 MPa while containing large volume of porosities at all length scales. PCP was further used to structure aluminomphosphate powders (AlPO4-17 and AlPO4-53) into strong functional monoliths. The aluminophosphate monoliths had strengths of 1 MPa, high CO2 uptake and were easy to regenerate. Zeolite Y, silicalite and ZSM5 were selected as potential zeolite adsorbents for removal of sulfur containing compound, e.g. ethyl mercaptan (EM) and propyl mercaptan (PM). A novel processing procedure was used to fabricate free-standing films and coatings of cellulose nanofibrils (CNF) with a high content of nanoporous zeolite; 89 w/w% and 96 w/w%, respectively. Thin flexible free-standing films and coatings of zeolite-CNF on paperboards with thickness around 100 µm and 40 µm, respectively, were produced. Headspace solid phase microextraction (SPME) coupled to gas chromatography- mass spectroscopy (GC/MS) analysis showed that the zeolite-CNF films can efficiently remove considerable amount of odors below concentration levels that can be sensed by the human olfactory system. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 5: Manuscript.</p>

There are still research gaps regarding the effects of key parameters such as water-to-cementitious materials ratio (w/cm), type of binder and pore structure characteristics on the response of concrete to special forms of sulfate attack: physical salt attack (PSA) and thaumasite sulfate attack (TSA). Hence, this study aims at developing an innovative type of concrete: nano-modified fly ash concrete, incorporating various dosages of nano-silica (NS) or nano-alumina (NA) and fly ash, and explores its efficiency in resisting various forms of sulfate attack.

Proton exchange membrane (PEM) fuel cells are competitive with other emerging technologies that are being considered for automotive transportation. Commercialization of PEM fuel cells would decrease emissions of criteria pollutants and greenhouse gases and reduce US dependence on foreign oil. However, many challenges exist that prevent this technology from being realized, including power requirements, durability, on-board fuel storage, fuel distribution, and cost. This dissertation focuses on fuel-cell durability, or more specifically catalyst stability. New techniques to comprehensively observe and pin-point degradation mechanisms are needed to identify stable catalysts. In this text, an in operando method to measure changes in catalyst particle size at the cathode of a PEM fuel cell is demonstrated. The pair distribution function analysis of X-ray diffraction patterns, generated from an operating fuel cell exposed to accelerated degradation conditions, was used to observe the growth of catalyst particles. The stability of Pt/C and PtCo/C electrodes, with different initial particle sizes, was monitored over 3000 potential cycles. The increase in particle size was fit to a linear trend as a function of cycle number for symmetric linear sweeps of potential. The most stable electrocatalyst was found to be alloyed PtCo with a larger initial particle size. A better understanding of oxide growth kinetics and its role in platinum dissolution is needed to develop a comprehensive fuel-cell performance model. There is an ongoing debate present in the current literature regarding which oxide species are involved in the oxide growth mechanism. This dissertation discusses the results of in operando X-ray absorption spectroscopy studies, where it was found that PtO2 is present at longer hold times. A new method to quantify EXAFS data is presented, and the extent of oxidation is directly compared to electrochemical data. This comparison indicated that PtO2 was formed at the expense of an initial oxide species, and these steps were included in a proposed mechanism for platinum oxidation. Simulations of platinum oxidation in literature have yet to fully replicate an experimental cyclic voltammogram. A modified Butler-Volmer rate equation is presented in this thesis. The effect of including an extra parameter, χ, in the rate equations was explored. It was found that while the χ-parameter allowed the cathodic peak width to be decoupled from the Tafel slope for the platinum-oxide reduction, its inclusion could not address all observed experimental characteristics. Exploration of this concept concluded that current is not a function of only potential and coverage. To that end, a heterogeneous oxide layer was introduced. In this model, place-exchanged PtO2 structures of varying energy states are formed through a single transition state. This treatment allowed, for the first time, the simulation of the correct current-potential behavior under varying scan rates and upper potential limits. Particle size plays a critical role in catalysts stability. The properties of nanoparticles can differ significantly from bulk values, yet few tools exist to measure these values at the nanoscale. Surface stress and surface energy are diagnostic criterion that can be used to differentiate nano from bulk properties. The pair distribution function technique was used to measure lattice strain and particle size of platinum nanoparticles supported on carbon. The effect of adsorbates on surface stress was examined and compared to previous literature studies. Furthermore, a methodology for measuring the surface energy of supported platinum nanoparticles has been developed. While the results of this work are significant, many more challenges need to be addressed before fuel-cell vehicles are marketed. Recommendations for future work in the field of catalyst durability are addressed.

The study aimed to identify mud brick and mud plaster technology of Hittites by examining some burnt mud brick walls of Shapinuwa Hittite city and to point out repair and conservation needs of those burnt mud brick structures. The walls were documented by mapping the visual decay forms. The bulk density, total porosity, water absorption by capillarity and water vapour permeability were obtained as basic physical properties. The mechanical properties were expressed by the modulus of elasticity and the uniaxial compressive strength. Compositional and mineralogical properties were determined by optical microscopy, XRD, TGA and SEM coupled with EDX, and by XRF analyses. In addition, pozzolanic activity of powdered samples was determined.. The samples studied had low bulk density, high porosity and high water vapour permeability. The Emod values and the UCS values showed that their mechanical properties were comparable with some historic mortars and bricks. The petrographic and mineralogical analyses of burnt materials indicated a mud brick composition containing fine and medium sized siliceous aggregates mainly composed of quartz. The binder was concluded to be composed of kaolinite illite and micritic calcite that indicated the use of ideal soil compositions by Hittites to make lime stabilized mud bricks, in terms of today standards. The temperature during the fire was estimated to be around 700-800 C. The high pozzolanicity of burnt mud bricks and plasters, provided an opportunity to repair the structure using pozzolanic lime mortars to produce good adhesion. The first results of consolidation treatments had shown that the physical and mechanical properties of burnt mud brick can be improved by impregnation with ethylsilicates such as Tegovakon V.