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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
851

Tratamento de efluente contendo urânio com zeólita magnética / Treatment of effluent containing uranium with magnetic zeolite

CRAESMEYER, GABRIEL R. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:42:11Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:08Z (GMT). No. of bitstreams: 0 / No presente estudo obteve-se com sucesso o compósito zeólita:magnetita usando-se como material de partida sulfato ferroso para síntese da magnetita e cinzas leves de carvão para síntese da fase zeolítica. A zeólita foi sintetizada por tratamento hidrotérmico alcalino e as nanopartículas de magnetita foram obtidas pela precipitação de íons Fe2+ em uma solução alcalina. Uma reprodutibilidade foi alcançada na preparação de diferentes amostras do nanocompósito zeolítico. O material foi caracterizado pelas técnicas de espectrometria de Infravermelho, difratometria de raios-X de pó, fluorescência de raios-X, microscopia eletrônica de varredura com a técnica de EDS, massa especifícia e área específica e por outras propriedades físico-químicas. O compósito era constituído pelas fases zeolíticas hidroxisodalita e NaP1, magnetita, quartzo e mulita das cinzas remanescentes do tratamento alcalino e magnetita incorporada na sua estrutura. A capacidade de remoção de U(VI) de soluções aquosas sobre o compósito zeólita:magnetita foi avaliada pela técnica descontínua. Os efeitos do tempo de contato e da concentração inicial do adsorbato sobre a adsorção foram avaliados. Determinou-se o tempo de equilíbrio do sistema e foram avaliados os modelos cinéticos de pseudo-primeira ordem, pseudo-segunda ordem e o modelo de difusão intrapartícula. Um tempo de contato de 120 min foi suficiente para a adsorção do íon uranilo alcançar o equilíbrio. A velocidade de adsorção seguiu o modelo cinético de pseudo-segunda-ordem, sendo que a difusão intrapartícula não era a etapa determinante do processo. Dois modelos de isotermas de adsorção, os modelos de Langmuir e de Freundlich, também foram avaliados. O modelo de Langmuir foi o que melhor se ajustou aos dados experimentais. A partir do modelo cinético e da isoterma que melhor descreveram o comportamento do sistema foi possível calcular os valores teóricos para a capacidade máxima de adsorção do U(VI) sobre o compósito zeólita:magnetita. As capacidades máximas de remoção calculadas foram de 20,7 mg.g-1 pela isoterma de Langmuir e de 23,4 mg.g-1 pelo modelo cinético de pseudo-segunda ordem. O valor experimental obtido foi 23,3 mg.g-1. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
852

Une approche efficace pour l’étude de la diagnosticabilité et le diagnostic des SED modélisés par Réseaux de Petri labellisés : contextes atemporel et temporel / An Efficient Approach for Diagnosability and Diagnosis of DES Based on Labeled Petri Nets : Untimed and Timed Contexts

Liu, Baisi 17 April 2014 (has links)
Cette thèse s'intéresse à l'étude des problèmes de diagnostic des fautes sur les systèmes à événements discrets en utilisant les modèles réseau de Petri. Des techniques d'exploration incrémentale et à-la-volée sont développées pour combattre le problème de l'explosion de l'état lors de l'analyse de la diagnosticabilité. Dans le contexte atemporel, la diagnosticabilité de modèles RdP-L est abordée par l'analyse d'une série de problèmes K-diagnosticabilité. L'analyse de la diagnosticabilité est effectuée sur la base de deux modèles nommés respectivement FM-graph et FM-set tree qui sont développés à-la-volée. Un diagnostiqueur peut être dérivé à partir du FM-set tree pour le diagnostic en ligne. Dans le contexte temporel, les techniques de fractionnement des intervalles de temps sont élaborées pour développer représentation de l'espace d'état des RdP-LT pour laquelle des techniques d'analyse de la diagnosticabilité peuvent être utilisées. Sur cette base, les conditions nécessaires et suffisantes pour la diagnosticabilité de RdP-LT ont été déterminées. En pratique, l'analyse de la diagnosticabilité est effectuée sur la base de la construction à-la-volée d'une structure nommée ASG et qui contient des informations relatives à l'occurrence de fautes. D'une manière générale, l'analyse effectuée sur la base des techniques à-la-volée et incrémentale permet de construire et explorer seulement une partie de l'espace d'état, même lorsque le système est diagnosticable. Les résultats des simulations effectuées sur certains benchmarks montrent l'efficacité de ces techniques en termes de temps et de mémoire par rapport aux approches traditionnelles basées sur l'énumération des états / This PhD thesis deals with fault diagnosis of discrete event systems using Petri net models. Some on-the-fly and incremental techniques are developed to reduce the state explosion problem while analyzing diagnosability. In the untimed context, an algebraic representation for labeled Petri nets (LPNs) is developed for featuring system behavior. The diagnosability of LPN models is tackled by analyzing a series of K-diagnosability problems. Two models called respectively FM-graph and FM-set tree are developed and built on the fly to record the necessary information for diagnosability analysis. Finally, a diagnoser is derived from the FM-set tree for online diagnosis. In the timed context, time interval splitting techniques are developed in order to make it possible to generate a state representation of labeled time Petri net (LTPN) models, for which techniques from the untimed context can be used to analyze diagnosability. Based on this, necessary and sufficient conditions for the diagnosability of LTPN models are determined. Moreover, we provide the solution for the minimum delay ∆ that ensures diagnosability. From a practical point of view, diagnosability analysis is performed on the basis of on-the-fly building of a structure that we call ASG and which holds fault information about the LTPN states. Generally, using on-the-fly analysis and incremental technique makes it possible to build and investigate only a part of the state space, even in the case when the system is diagnosable. Simulation results obtained on some chosen benchmarks show the efficiency in terms of time and memory compared with the traditional approaches using state enumeration
853

Evolution physico-chimique des liants bas PH hydratés : influence de la température et mécanisme de rétention des alcalins / Physico-chemical evolution of low-pH cements : influence of the temperature and the retention mechanisme of alkalins

Bach, Thi thuy ha 16 November 2010 (has links)
Dans un site de stockage profond de déchets radioactifs, l’utilisation de matériaux à base de ciment Portland en association avec de l’argile pourrait se révéler inadaptée en raison de leur forte alcalinité. Une alternative serait de mettre en œuvre des ciments générant des solutions interstitielles de pH réduit (de l’ordre de 11 au lieu de 13,5 pour un CEM I). Les formulations étudiées dans cette thèse font appel à des ciments composés (également appelés « liant bas pH ») élaborés à partir de mélanges binaires (CEM I / fumée de silice) ou ternaires (CEM I / fumée de silice / cendres volantes ou laitier), avec de forts taux de substitution du CEM I (de 30% à 80%). Le travail réalisé répond à un double objectif : (i) étudier l’évolution chimique des liants bas pH à 50°C ou 80°C, températures qui pourraient être rencontrées dans certaines zones du stockage, et (ii) préciser les mécanismes à l’origine de la bonne rétention des alcalins par ces liants hydratés. (i) Le suivi sur une période d’un an de pâtes de liant bas pH montre que l’accroissement de la température de 20 à 80°C accélère l’hydratation des liants et favorise la consommation de la portlandite. L’allongement et la réticulation des chaînes de silicates des C-A-S-H est mise en évidence par RMN de l’27Al et du 29Si. L’ettringite observée dans les pâtes conservées à 20°C est par ailleurs déstabilisée. Les sulfates ainsi relâchés sont pour partie adsorbés sur les C-A-S-H et dissous dans la solution interstitielle. Le pH de cette dernière est réduit de 1,7 à 2,2 unités selon les formulations. En revanche, les fractions solubles d’alcalins n’évoluent pas de façon importante. Le liant ternaire T1 composé de 37,5% de CEM I, 32,5% de fumée de silice et 30% de cendres volantes est le seul des ciments étudiés à conduire à un pH de solution interstitielle inférieur à 11 aux trois températures considérées (20, 50 et 80°C - échéances 6 mois et 1 an). Son évolution à plus long terme a pu être simulée à l’aide de systèmes modèles reproduisant sa composition chimique à partir d’oxydes réactifs. A l’équilibre thermodynamique, l’assemblage minéralogique est constitué de C-A-S-H (rapports Ca/Si et Al/Si de 0,75 et 0,15 respectivement) ainsi que d’hydroxyde d’aluminium et de silice amorphes, et il impose un pH de 10,3 à 20°C. (ii) Ce sont les C-A-S-H qui jouent le rôle essentiel dans la rétention des alcalins. Le mécanisme mis en jeu est celui d’une compensation des charges négatives des C-A-S-H par interaction électrostatique. Il existe une sélectivité de sorption : le potassium est mieux retenu que le sodium. Celle-ci pourrait être attribuée en première approche à la différence de rayon solvaté entre ces ions. Une modélisation Monte Carlo des interactions électrostatiques entre des particules de C-S-H et un électrolyte contenant des ions sodium et potassium montre cependant que cette hypothèse ne suffit pas à elle seule à expliquer la sélectivité observée expérimentalement. / Because of their high alkalinity, Portland cement (OPC)-based materials may have deleterious effects in an underground waste repository. A solution would be to use low-alkalinity cements (also referred as low-pH cements) generating interstitial solutions with a reduced pH (11 instead of 13.5 for OPC), and thus showing an improved chemical compatibility with the repository environment. In this work, the investigated formulations were based on binary (OPC / silica fume) or ternary (OPC / silica fume / slag or fly ash) blends, with high substitution levels of CEM I (from 30% to 80%). This research project met two main objectives: (i) study the chemical evolution of low-pH cements at 50°C or 80°C, since such temperatures could be encoutered in certain zones of the waste repositories, and (ii) determine the mechanisms of alkali retention by hydrated low-pH cements. (i) Investigation of low-pH cement pastes with ongoing hydration over one year showed that increasing the temperature from 20°C to 80°C accelerated cement hydration and favoured the depletion of portlandite. A lengthening of the C-A-S-H silicate chains was also detected by 27Al and 29Si NMR analyses. Besides, ettringite precipitated at 20°C, but was destabilised at higher temperature. The released sulphates were partly adsorbed on the C-A-S-H and dissolved in the interstitial solution. The pH of this solution was reduced from 1.7 to 2.2 units depending on the formulations. The soluble fractions of alkalis did not significantly change with temperature. Among the five investigated blends, ternary binder T1 (37.5% CEM I, 32.5% silica fume, 30% fly ash) was the only one giving a pore solution pH lower than 11 at 20, 50 and 80°C (curing time of 6 months and 1 year). Its long-term evolution was simulated by model systems reproducing its chemical composition with reactive oxides. At equilibrium, the hydrate assemblage comprised C-A-S-H (Ca/Si and Al/Si ratios of 0.75 and 0.15 respectively), amorphous silica and aluminium hydroxide. It led to a pH of 10.3 at 20°C. (ii) C-A-S-H hydrates played a major role in the retention of alkalis. Sorption of potassium was higher than that of sodium and mainly resulted from electrostatic interactions with C-A-S-H. Monte Carlo modelling of these interactions showed that the difference of solvated radii between these ions could not explain by itself the sorption selectivity experimentally observed.
854

Physicochemical studies regarding the utilization of wood- and peat-based fly ash

Pesonen, J. (Janne) 11 October 2016 (has links)
Abstract The main aim of the European Union’s waste legislation and the corresponding Finnish waste legislation is to reduce the production of waste. Further, the aims of the European Union’s growth strategy are to reduce the production of greenhouse gases, increase the use of renewable energy, and improve energy efficiency. According to the renewed Waste Tax Act, a waste tax has to be paid on all fly ashes that are deposited in landfills in Finland. A large amount of wood- and peat-based fly ashes are formed annually in Finland, and the amount is likely to increase in the future due to the increasing use of renewable energy. Previously, these ashes have mainly been deposited in industrial landfills, but the need to utilize the fly ashes has increased recently due to changes in waste legislation. In this thesis, several issues related to the utilization of wood- and peat-based fly ash were studied, with the general objective of improving the utilization potential of such ashes. As the first stage of this research, the suitability of willow ash for use as a fertilizer was studied. Willow ash would be well suited for use as a fertilizer due to its very high nutrient content. However, cadmium, a heavy metal, was found to be enriched in the ashes of the studied willow species. Due to this, special attention should be paid when choosing willow species for energy production. In the second stage of the research, the possibility of improving the strength development of wood- and peat-based fly ashes, as well as the possibility of stabilizing fly ash containing high amounts of heavy metals via the addition of cement and/or alkali activation, was investigated. Strength development was found to be dependent on the amount of reactive calcium and the ratio between that amount of reactive calcium and the sum of the reactive silicon, aluminum, and sulfur (Ca/(Si + Al + S)). The studied methods performed well in terms of stabilizing barium, copper, lead, and zinc. During the next stage, the effect of different chemical digestion methods, which are regulated by the Finnish waste legislation, on the utilization potential of fly ash was studied. The digestion method had a significant impact on the results of the potassium content analysis, which could affect the possibility of using fly ash as a fertilizer. As the final stage of the research, the co-granulation of ash with sewage sludge and lime was studied. From a technical point of view, the co-granulation was successful, although the compressive strength of the granules was low. Additionally, an insufficient nitrogen content was achieved with a sludge addition of 20-40 weight%. / Tiivistelmä Euroopan unionin jätelainsäädännön ja sitä vastaavan suomalaisen lainsäädännön tavoitteena on ehkäistä jätteiden muodostumista. Euroopan Unionin kasvustrategian tavoitteena on vähentää kasvihuonekaasupäästöjä, lisätä uusiutuvan energian käyttöä ja parantaa energiatehokkuutta. Uudistetun jäteverolain mukaan kaikista kaato-paikoille sijoitetuista lentotuhkista tulee Suomessa maksaa jäteveroa. Suomessa puu- ja turveperäisiä lentotuhkia muodostuu vuosittain suuria määriä ja määrä tulee vielä kasvamaan uusiutuvan energiankäytön lisääntyessä. Aiemmin nämä tuhkat ovat päätyneet pääasiassa läjitykseen teollisuuden kaatopaikoille, mutta muuttuneen jätelainsäädännön seurauksena tarve hyödyntää lentotuhkia on lisääntynyt. Tässä väitöstyössä tutkittiin puu- ja turveperäisten tuhkien hyödyntämiseen liittyviä kysymyksiä. Työn yleistavoitteena oli parantaa tuhkien hyödyntämis-mahdollisuuksia. Tutkimuksen ensimmäisessä vaiheessa tutkittiin pajutuhkan soveltuvuutta lannoitteeksi. Pajutuhka soveltuisi hyvin lannoitteeksi erittäin hyvien ravinne-pitoisuuksien ansiosta. Raskasmetalleista kadmiumin havaittiin kuitenkin rikastuvan tutkittujen pajulajien tuhkiin. Tähän tulisi kiinnittää erityishuomiota, kun pajulajeja valitaan energiantuotantoa varten. Tutkimuksen toisessa vaiheessa selvitettiin mahdollisuutta parantaa turpeen ja puun lentotuhkien lujittumista sekä raskasmetallipitoisen lentotuhkan stabiloimista sementtilisäyksen ja/tai alkaliaktivoinnin avulla. Lujuuden kehitys riippui reaktiivisen kalsiumin määrästä sekä reaktiivisen kalsiumin määrän ja reaktiivisten piin, alumiinin ja rikin määrien summan välisestä suhteesta (Ca/(Si + Al + S)). Tutkitut menetelmät toimivat hyvin bariumin, kuparin, lyijyn ja sinkin stabiloinnissa. Seuraavassa vaiheessa selvitettiin Suomen lainsäädännössä määritettyjen kemiallisten hajotusmenetelmien vaikutusta tuhkan hyödyntämispotentiaaliin. Hajotusmenetelmällä oli suuri merkitys kaliumin pitoisuutta määritettäessä, mikä voi vaikuttaa lentotuhkan hyödynnettävyyteen lannoitteena. Viimeisessä vaiheessa tutkittiin tuhkan yhteisrakeistusta lietteen ja kalkin kanssa. Teknisesti yhteisrakeistus onnistui hyvin, mutta rakeiden puristuslujuus oli alhainen. Lisäksi 20 - 40 paino% lietelisäyksellä ei rakeisiin saatu riittävän korkeaa typpipitoisuutta.
855

Assessment of Leachate Characteristics and Geotechnical Properties of Municipal Solid Waste Landfill

Naveen, B P January 2016 (has links) (PDF)
Solid Waste Management is one of the essential services provided by local bodies to keep the urban areas clean. Often it is poorly rendered as it is unscientific, out-dated and inefficient. With the rapid increase in population, livening standards, the generation rates of solid waste are increasing drastically. The landfill waste includes both organic and inorganic wastes as it is not often effectively segregated before disposal. The problem is acute in developing countries such as India. Bangalore city, with a population of about 10.18 million and more than 2000 industries, generates about 4,500 TPD of municipal solid waste. Of this Presently, various municipal solid waste processing units in Bangalore can handle only about 2100 TPD of waste. Mavallipura landfill developed and operated by M/s. Ramky Environmental Engineers, located 40 km away from Bangalore, is being used for disposing of about 1000 TPD, the installed capacity being only 600 TPD of waste. There are also a few dumps in around Bangalore due to historical reasons and insufficient capacity of various designated landfills. To reclaim the old dump sites/closed landfill sites for infrastructural development, it is necessary to know their geotechnical characteristics. Within the Landfill, the characteristics of the waste may change with depth due to degraded wastes as it has been dumped over a period of time. The physical parameters, chemical properties as well as the geotechnical behaviour of the waste change with depth. MSW is known to be a heterogeneous material of varying constituent types and dimensions, containing elements that degrade with time. To consider MSW as a geo-material to support the foundation of structures such as buildings and pavement, an analysis of the bearing capacity of the foundation and further long-term settlement of MSW is essential. The MSW samples are retrieved from a Mavallipura landfill site, Bangalore and analysed for important geotechnical properties such as compaction characteristics, shear strength, permeability, compressibility behaviour and dynamic properties of MSW using ultrasonic and cyclic triaxial tests. This research thus aims to provide valuable information about landfill sites for reclamation, closure and infrastructural development after the closure of landfills. Scanty data are available on the geotechnical properties of waste from landfill sites with varying degrees of degradation. This landfill site is selected as there is a huge environmental concern regarding the soil and groundwater contamination in the area and also can represent a typical landfill scenario in tropical regions. Quantification, quality assessment, consequent treatment and management of leachate have become a monstrous problem world over. In this context, the present study envisages to study the physicochemical and biological characterization of representative urban municipal landfill leachate and nearby water bodies and attempts to figure out relationships between the various parameters together with understanding the various processes for chemical transformations. The analysis shows intermediate leachate age (5-10 years) with higher nutrient levels i.e. 10,000 - 12,000 mg/l and ~2,000 - 3,000 mg/l of carbon (COD) and nitrogen (TKN) respectively. Elemental analysis and underlying mechanisms reveal chemical precipitation and co-precipitation as the vital processes in leachate pond systems resulting in accumulation of trace metals in these systems. The microbial analysis also correlated with specific factors relevant to redox environments that show a gradient in nature and the abundance of biotic diversity with a change in leachate environment. Finally, the quality and the contamination potential of the sampled leachate were performed with the help of potential leachate index (LPI) analysis and water quality index (WQI) analysis for surrounding water bodies (namely surface pond and open well) of Mavallipura landfill site. A geotechnical testing program has been drawn to evaluate the engineering properties of municipal solid waste samples retrieved from a landfill at Mavallipura at various depths through augur within the landfill dumped area. Laboratory studies included are composition, moisture content, particle size analysis, compaction, permeability, direct shear test, consolidation, triaxial compression test. For the laboratory tests, we had considered maximum particle sizes of less than 4.75 mm only. Standard Proctor Compaction tests yielded a maximum dry density of 7.0kN/m3 at 50% optimum moisture content. The permeability of MSW results shows in the range of 4x10-4 cm/sec. Compression index of MSW is 0.46980 and recompression index of MSW is 0.09454. Results obtained from the rectangular hyperbola method are compared with Casagrande and Taylor methods to prove that this method is reliable equally, and results are reasonably accurate. Based on direct shear tests, the MSW sample exhibited continuous strength gain with an increase in shear strain (16%) to define strength. The cohesion of MSW was 10kPa and friction angle is 34°. Based on the elastic constants results obtained from the direct shear test found to be very soft material. In the triaxial test, the MSW sample exhibited continuous strength gain with an increase in axial strain. The frictional component is increased due to sliding and rolling of fibrous particles over one another resulting in the development of apparent cohesion due to antiparticle bonds within the MSW material. Landfills are an integral part of waste management, and disastrous consequences can happen if seismic vulnerability of these landfills is not considered. Dynamic properties of MSW are required to perform seismic response analysis of MSW landfills, but there is no good understanding of the dynamic shear strength of MSW in literature. A comprehensive laboratory cyclic triaxial testing program has been taken up to determine the properties at different densities, confining pressures and shear strains. MSW degrades with time, and its shear modulus and damping are expected to vary with time and degradation. For the density of 6 kN/m3 the dynamic shear modulus values for MSW varied from 0.68 MPa to 5.38 MPa and damping ratio varied from 20% to 40% for MSW. For the density of 7 kN/m3 the dynamic shear modulus values for MSW varied from 1.8 MPa to 7.5 MPa and Damping ratio varied from 23% to 40% for MSW. For the density of 8kN/m3 dynamic shear modulus values for MSW varied from 2.46 MPa to 8.00MPa and damping ratio varied from 16% to 33% for MSW. Also, the ultrasonic testing method was used for determining the dynamic properties at low strains. The Ultrasonic test results indicated that with an increase in density of the sample and with decreased void ratio, the pulse propagation velocity (Vp) increases. With an increase in the density, the shear wave velocity and elastic constants (elastic modulus and shear modulus) increase. The elastic constant values obtained from the ultrasonic test are higher compared to values obtained from unconsolidated-undrained triaxial tests. Also, the carbon stored in the buried organic matter in Mavallipura landfill is estimated. Total organic carbon increases steeply with an increase in depth and is significantly high at a depth of 6 m. Subsurface properties cannot be specified but must be analysed through in-situ tests. The in-situ testing that are carried out in a landfill are boring, sampling, standard penetration test (SPT), dynamic cone penetration test (DCPT) and plate load tests (under static and cyclic condition). A correlation between corrected SPT ‘N’ values and measured using shear wave velocities has been developed for Mavallipura landfill site. Results show that the corrected SPT- N values increase with depth. Corrected N-values are used in the landfill design, so they are consistent with the design method, and correlations are useful. The results obtained from the dynamic cone penetration tests shows lower value when to compare with standard penetration test. The unit weight profile with depth ranged from a low unit weight of 2.48 kN/m3 near the surface to a highest value of approximately 9.02 kN/m3 at a depth of 6 m. The highest temperatures for landfills were reported at mid-waste elevations with temperatures decreasing near the top. The bearing pressure-settlement curves for plate size 75cm and 60cm presented similar behaviour while the plate size of 60cm curve presents a lesser settlement of 70mm, compared to with plate size of the 75cm curve with the settlement of 80mm and failure mode could be classified as punching shear. The cyclic plate load test with plate size of 60cm and 75cm were carried out on the soil cover. The elastic constants were found to be 73.87 and 96.84 kPa/mm and for 60 and 75cm plates respectively. Geophysical testing may not be as precise but has the benefit of covering large areas at small costs and sometimes can locate features that might be missing by conventional borings. Multichannel analysis of surface waves (MASW) is an indirect geophysical method used in the landfill for the characterization of the municipal solid waste site. The Mavallipura landfill was surveyed up to the length of about 35m at the top level. A series of one-dimensional and two-dimensional MASW surveys used active seismic sources such as sledgehammer (5kg) and propelled energy generator (PEG-40) was used. This hammer was instrumented with geophones to trigger record time. All the testing has been carried out with geophone spacing of 1m and recorded surface wave arrivals using the source to first receiver distance as 5m with recording length of 1000 millisecond and the recording sampling interval of 0.5 milliseconds (ms) were applied. Results shows that the PEG-40 hammer can generate the longest wavelength with a maximum depth of penetration. The shear wave velocity varies from 75 to 155 m/s with an increase in depth of about 27.5m. Based on the site characterization at the landfill site, it was found that the Mavallipura landfill site can be categorized as very loose, and it is still in a continued stage of degradation. Shear wave and P-wave velocity profile for eight major locations in the study area were determined and variation of waste material stiffness corresponding to the in-situ state with depth, was also evaluated. Also, MASW survey has been carried out to develop dispersion curve on another landfill site at Bhandewadi, Nagpur. MASW system consisting of 24 channels geode seismograph with 24 geophones of 4.5Hz capacity is used in this investigation. The seismic waves were created by sledgehammer with 30cmx 30cmx2cm size hammer plate with ten shots. These waves were captured by the geophones/receivers and further analyzed by inversion. The results indicated that near surface soils(less than 3m depth) approximately the to 5mm, and with 85% of dry weight basis of waste particles with sizes less than 10mm, the shear wave velocity varies from 75 to 140 m/s (frequency ranges from 30 to 23Hz). With the increase in 6.5m depth, the shear wave velocity ranged from 140 to 225m/s (frequency ranges 23 to 13Hz). Overall, the results of the study showed that seismic surveys have the potential to capture the changes in dynamic properties like shear wave velocity and Poisson’s ratio of the depth of MSW landfill to infer the extent of degradation and provide dynamic properties needed for seismic stability evaluations. Based on the in situ and laboratory results of this study and a review of the literature, the unit weight, shear wave velocity, strain-dependent normalized shear modulus reduction and material damping ratio relationships for Mavallipura landfill are developed and also validated using semi-empirical methods. Finally, seismic response analysis of Mavallipura landfill has been carried out using the computer programs like SHAKE 2000 and DEEPSOIL. Results show that the unit weight is increased with depth in response to the increase in overburden stress. The proposed material damping ratio and normalized shear modulus reduction curve lie close to the profile given in the literature for landfills composed of waste materials with 100% particles sized less than 20mm. Peak spectral acceleration at 5% damping value is 0.7g for 0.07 sec in SHAKE 2000 and peak spectral acceleration at 5% damping value is 0.63g for 0.04 sec in DEEPSOIL. Amplification ratio is 6.11 at 1.1l Hz in SHAKE2000 and 4.65 at 2.67Hz in DEEPSOIL. Peak ground acceleration (PGA) for the landfill site, it is observed PGA has decreased from 0.3g to 0.15g in DEEPSOIL and PGA has decreased from 0.33g to 0.15g in SHAKE2000. The studies presented in the thesis brought out the importance of characterization of municipal solid waste leachate regarding metabolism and treatment/degradation of Mavallipura landfill leachate. For municipal solid waste of with sizes ranging from 0.08 coefficient of permeability being about 10-4 cm/sec, the compression index was about 0.47. A more reliable method of calculating the coefficient of consolidation has been recommended. Correlations between shear wave velocity and SPT-N values has been developed for the Mavallipura landfill site. The results showed that the dynamic cone penetration tests values are lower than indicated by standard penetration tests. The cyclic plate load tests carried out with plate sizes of 75cm and 60cm showed that elastic constants of 96.84 kPa/mm and 73.87kPa/mm respectively. MSW properties evaluated in this thesis are compared with those of soft clays. The MSW properties showed higher values (strength and SBC) and lower values of compressibility, compared with those of soft clays. Thus foundation improvement on MSW is less challenging than foundations on soft soils. Also stabilization of MSW with other solid wastes such as fly ash can be considered as an economical option. Based on detailed studies the importance of unit weight, shear wave velocity, strain-dependent normalized shear modulus reduction and material damping ratio relationships for landfill waste have been developed. Based on the site characterization, the waste landfill has been categorized as very loose material, which is still in a degradation process. SHAKE2000 software shows higher PGA value comparing with DEEPSOIL.
856

Traitement à haute pression et haute température de déchets de métaux lourds vers de nouveaux matériaux stables / High pressure and high temperature treatment of heavy metal waste, towards new stable materials

Karnis, Aurélie 08 October 2009 (has links)
Les REFIOM (Résidus d'Epuration des Fumées d'Incinération des Ordures Ménagères) issus de l'incération des déchets ménagers contiennent des métaux lourds comme le plomb ou le cadmium et sont en France uniquement stockés en centre d'enfouissement technique de classe 1 pour dangereux, en étant stabilisés par une vitrification. Afin de trouver des solutions pour le stockage ou la valorisation à long terme des REFIOM sans danger pour l'environnement, nous avons ciblé les vitrocéramiques et les céramiques frittées à hautes températures et hautes pressions. Nous avons utilisé des méthodes de la minéralogie physique par l'intermédiaire de synthèses à hautes températures, de synthèses à hautes températures et à hautes pressions en autoclave à chauffage externe, d'observations en microscopie électronique à balayage, de microanalyses chimiques EDX (Energy Dispersive X-Ray spectrometry), d'analyses en microsondes, de caractérisation structurale par diffraction de rayons X et d'expériences de lixiviation dynamique. Nous avons mis au point des protocoles de synthèses et d'analyses. Par ce biais, nous constatons pour les vitrocéramiques que le plomb ou le cadmium sont incorporés dans des cristallites et dans des nouvelles phases cristallines, eux-mêmes englobés dans une matrice vitreuse. Cette voie dite "double barrière" (cristaux + verre) semble prometteuses pour l'immobilisation du plomb et du cadmium (au regard des analyses EDX et des expériences de lixiviation). Pour les céramiques frittées, comme pour les SYNROC (SYNthetic ROCk) synthétisées pour les déchets nucléaires, de nouvelles phases cristallines incorporant Pb et Cd sont observées et seraient a priori résistantes pour le stockage de ces éléments toxiques. Dans ces deux cas de nouveaux matériaux capables d'incorporer massivement du plomb et du cadmium ont été mis en évidence. Des tests de durabilité permettront d'envisager une valorisation éventuelle de tels matériaux / MSWI 5Municipal Solide Waste Incinerator) fly ashes from the incineration of domestic waste contain heavy metals such as lead or cadmium. In France, these fly ashes are only stored under vitrified forms in class-1 type landfills for hazardous waste. In order to find solutions for long-term storage or valorization of the MSWI fly ashes, we studied glass-ceramics and sintered ceramics at high pressures and/or hight temperature. We used methods of mineral physics to : synthetize at high temperature, synthetize at higt temperature and high pressure using autoclaves with external heating system, observe by electron microcopy, make EDX (Energy Dispersive X-Ray spectrometry) chemical microanalysis, make microprobe analysis, structurally characterize and perform leaching test. We established experimental protocols for the synthesis and analysis of produced materials. For glass-ceramics, we observe that lead and cadmium are incorporated inside expected crystallites and new crystal phases, themselves embedded by a glassy matrix. This so-called "double barrier" (crystals + glass) is a promising way towards a substainable of lead and cadmium (after EDX analysis and leaching experiements). For sintered ceramics, as for the SYNROC (SYNthetic ROCk) with nuclear waste, new crystal phases incorporating Pb and Cd are found and might display a high resistant for the storage of these toxic elements. In both cases, new materials incorporating large amounts of lead and cadmium were formed. Durability tests may give new ways for a valorization of such materials
857

Sex Chromosome Evolution in Blow Flies

Anne Amarila Andere (9120365) 28 July 2020 (has links)
<div>Chromosomal mechanisms of sex determination vary greatly in phylogenetically closely related species, indicative of rapid evolutionary rates. Sex chromosome karyotypes are generally conserved within families; however, many species have derived sex chromosome configurations. Insects display a plethora of sex chromosome systems due to rapid diversification caused by changes in evolutionary processes within and between species. A good example of such a system are insects in the blow fly family Calliphoridae. While cytogenetic studies observe that the karyotype in blow flies is highly conserved (five pairs of autosomal chromosomes and one pair sex chromosome), there is variation in sex determining mechanisms and sex chromosome structure within closely related species in blow flies. The evolutionary history of sex chromosomes in blow fly species have not been fully explored. Therefore, the objective of this research was to characterize the sex chromosome structures in four species of blow flies and investigate the selective forces which have played a role in shaping the diverse sex chromosome system observed in blow flies. The blow fly species used in this study are Phormia regina, Lucilia cuprina, Chrysomya rufifacies and Chrysomya albiceps. Phormia regina,and Lucilia cuprina have a heteromorphic sex chromosome system and are amphogenic (females produce both male and female offspring in equal ratio). In contrast, Chrysomya rufifacies and Chrysomya albiceps, have a homomorphic sex chromosome system, are monogenic (females produce unisexual progeny), have two types of females (arrhenogenic females – male producers and thelygenic females – female producers), and sex of the offspring is determined by the maternal genotype. </div><div>To accomplish these tasks, a total of nine male and female individual draft genomes for each of the four species (including three individual draft genomes of Chrysomya rufifacies – male, and the two females) were sequenced and assembled providing genomic data to explore sex chromosome evolution in blow flies. Whole genome analysis was utilized to characterize and identify putative sex chromosomal sequences of the four blow fly species. Genomic evidence confirmed the presence of genetically differentiated sex chromosomes in P. regina and L. cuprina; and genetically undifferentiated sex chromosomes in C. rufifacies and C. albiceps. Furthermore, comparative analysis of the ancestral Dipteran sex chromosome (Muller element F in Drosophila) was determined to be X-linked in P. regina and L. cuprina contributing to sex chromosome differentiation but not sex-linked in C. rufifacies and C. albiceps. Evolutionary pressures are often quantified by the ratio of substitution rates at non-synonymous (dN) and synonymous (dS) sites. Substitution rate ratio analysis (dN/dS) of homologous genes indicated a weaker purifying selection may have contributed to the loss of sex-linked genes in Muller element F genes of the undifferentiated sex chromosome as compared to the differentiated sex chromosome system. Overall, the results presented herein greatly expands our knowledge in sex chromosome evolution within blow flies and will reinforce the study of sex chromosome evolution in other species with diverse sex chromosome systems.</div><div><br></div>
858

Novel chemometric proposals for advanced multivariate data analysis, processing and interpretation

Vitale, Raffaele 03 November 2017 (has links)
The present Ph.D. thesis, primarily conceived to support and reinforce the relation between academic and industrial worlds, was developed in collaboration with Shell Global Solutions (Amsterdam, The Netherlands) in the endeavour of applying and possibly extending well-established latent variable-based approaches (i.e. Principal Component Analysis - PCA - Partial Least Squares regression - PLS - or Partial Least Squares Discriminant Analysis - PLSDA) for complex problem solving not only in the fields of manufacturing troubleshooting and optimisation, but also in the wider environment of multivariate data analysis. To this end, novel efficient algorithmic solutions are proposed throughout all chapters to address very disparate tasks, from calibration transfer in spectroscopy to real-time modelling of streaming flows of data. The manuscript is divided into the following six parts, focused on various topics of interest: Part I - Preface, where an overview of this research work, its main aims and justification is given together with a brief introduction on PCA, PLS and PLSDA; Part II - On kernel-based extensions of PCA, PLS and PLSDA, where the potential of kernel techniques, possibly coupled to specific variants of the recently rediscovered pseudo-sample projection, formulated by the English statistician John C. Gower, is explored and their performance compared to that of more classical methodologies in four different applications scenarios: segmentation of Red-Green-Blue (RGB) images, discrimination of on-/off-specification batch runs, monitoring of batch processes and analysis of mixture designs of experiments; Part III - On the selection of the number of factors in PCA by permutation testing, where an extensive guideline on how to accomplish the selection of PCA components by permutation testing is provided through the comprehensive illustration of an original algorithmic procedure implemented for such a purpose; Part IV - On modelling common and distinctive sources of variability in multi-set data analysis, where several practical aspects of two-block common and distinctive component analysis (carried out by methods like Simultaneous Component Analysis - SCA - DIStinctive and COmmon Simultaneous Component Analysis - DISCO-SCA - Adapted Generalised Singular Value Decomposition - Adapted GSVD - ECO-POWER, Canonical Correlation Analysis - CCA - and 2-block Orthogonal Projections to Latent Structures - O2PLS) are discussed, a new computational strategy for determining the number of common factors underlying two data matrices sharing the same row- or column-dimension is described, and two innovative approaches for calibration transfer between near-infrared spectrometers are presented; Part V - On the on-the-fly processing and modelling of continuous high-dimensional data streams, where a novel software system for rational handling of multi-channel measurements recorded in real time, the On-The-Fly Processing (OTFP) tool, is designed; Part VI - Epilogue, where final conclusions are drawn, future perspectives are delineated, and annexes are included. / La presente tesis doctoral, concebida principalmente para apoyar y reforzar la relación entre la academia y la industria, se desarrolló en colaboración con Shell Global Solutions (Amsterdam, Países Bajos) en el esfuerzo de aplicar y posiblemente extender los enfoques ya consolidados basados en variables latentes (es decir, Análisis de Componentes Principales - PCA - Regresión en Mínimos Cuadrados Parciales - PLS - o PLS discriminante - PLSDA) para la resolución de problemas complejos no sólo en los campos de mejora y optimización de procesos, sino también en el entorno más amplio del análisis de datos multivariados. Con este fin, en todos los capítulos proponemos nuevas soluciones algorítmicas eficientes para abordar tareas dispares, desde la transferencia de calibración en espectroscopia hasta el modelado en tiempo real de flujos de datos. El manuscrito se divide en las seis partes siguientes, centradas en diversos temas de interés: Parte I - Prefacio, donde presentamos un resumen de este trabajo de investigación, damos sus principales objetivos y justificaciones junto con una breve introducción sobre PCA, PLS y PLSDA; Parte II - Sobre las extensiones basadas en kernels de PCA, PLS y PLSDA, donde presentamos el potencial de las técnicas de kernel, eventualmente acopladas a variantes específicas de la recién redescubierta proyección de pseudo-muestras, formulada por el estadista inglés John C. Gower, y comparamos su rendimiento respecto a metodologías más clásicas en cuatro aplicaciones a escenarios diferentes: segmentación de imágenes Rojo-Verde-Azul (RGB), discriminación y monitorización de procesos por lotes y análisis de diseños de experimentos de mezclas; Parte III - Sobre la selección del número de factores en el PCA por pruebas de permutación, donde aportamos una guía extensa sobre cómo conseguir la selección de componentes de PCA mediante pruebas de permutación y una ilustración completa de un procedimiento algorítmico original implementado para tal fin; Parte IV - Sobre la modelización de fuentes de variabilidad común y distintiva en el análisis de datos multi-conjunto, donde discutimos varios aspectos prácticos del análisis de componentes comunes y distintivos de dos bloques de datos (realizado por métodos como el Análisis Simultáneo de Componentes - SCA - Análisis Simultáneo de Componentes Distintivos y Comunes - DISCO-SCA - Descomposición Adaptada Generalizada de Valores Singulares - Adapted GSVD - ECO-POWER, Análisis de Correlaciones Canónicas - CCA - y Proyecciones Ortogonales de 2 conjuntos a Estructuras Latentes - O2PLS). Presentamos a su vez una nueva estrategia computacional para determinar el número de factores comunes subyacentes a dos matrices de datos que comparten la misma dimensión de fila o columna y dos planteamientos novedosos para la transferencia de calibración entre espectrómetros de infrarrojo cercano; Parte V - Sobre el procesamiento y la modelización en tiempo real de flujos de datos de alta dimensión, donde diseñamos la herramienta de Procesamiento en Tiempo Real (OTFP), un nuevo sistema de manejo racional de mediciones multi-canal registradas en tiempo real; Parte VI - Epílogo, donde presentamos las conclusiones finales, delimitamos las perspectivas futuras, e incluimos los anexos. / La present tesi doctoral, concebuda principalment per a recolzar i reforçar la relació entre l'acadèmia i la indústria, es va desenvolupar en col·laboració amb Shell Global Solutions (Amsterdam, Països Baixos) amb l'esforç d'aplicar i possiblement estendre els enfocaments ja consolidats basats en variables latents (és a dir, Anàlisi de Components Principals - PCA - Regressió en Mínims Quadrats Parcials - PLS - o PLS discriminant - PLSDA) per a la resolució de problemes complexos no solament en els camps de la millora i optimització de processos, sinó també en l'entorn més ampli de l'anàlisi de dades multivariades. A aquest efecte, en tots els capítols proposem noves solucions algorítmiques eficients per a abordar tasques dispars, des de la transferència de calibratge en espectroscopia fins al modelatge en temps real de fluxos de dades. El manuscrit es divideix en les sis parts següents, centrades en diversos temes d'interès: Part I - Prefaci, on presentem un resum d'aquest treball de recerca, es donen els seus principals objectius i justificacions juntament amb una breu introducció sobre PCA, PLS i PLSDA; Part II - Sobre les extensions basades en kernels de PCA, PLS i PLSDA, on presentem el potencial de les tècniques de kernel, eventualment acoblades a variants específiques de la recentment redescoberta projecció de pseudo-mostres, formulada per l'estadista anglés John C. Gower, i comparem el seu rendiment respecte a metodologies més clàssiques en quatre aplicacions a escenaris diferents: segmentació d'imatges Roig-Verd-Blau (RGB), discriminació i monitorització de processos per lots i anàlisi de dissenys d'experiments de mescles; Part III - Sobre la selecció del nombre de factors en el PCA per proves de permutació, on aportem una guia extensa sobre com aconseguir la selecció de components de PCA a través de proves de permutació i una il·lustració completa d'un procediment algorítmic original implementat per a la finalitat esmentada; Part IV - Sobre la modelització de fonts de variabilitat comuna i distintiva en l'anàlisi de dades multi-conjunt, on discutim diversos aspectes pràctics de l'anàlisis de components comuns i distintius de dos blocs de dades (realitzat per mètodes com l'Anàlisi Simultània de Components - SCA - Anàlisi Simultània de Components Distintius i Comuns - DISCO-SCA - Descomposició Adaptada Generalitzada en Valors Singulars - Adapted GSVD - ECO-POWER, Anàlisi de Correlacions Canòniques - CCA - i Projeccions Ortogonals de 2 blocs a Estructures Latents - O2PLS). Presentem al mateix temps una nova estratègia computacional per a determinar el nombre de factors comuns subjacents a dues matrius de dades que comparteixen la mateixa dimensió de fila o columna, i dos plantejaments nous per a la transferència de calibratge entre espectròmetres d'infraroig proper; Part V - Sobre el processament i la modelització en temps real de fluxos de dades d'alta dimensió, on dissenyem l'eina de Processament en Temps Real (OTFP), un nou sistema de tractament racional de mesures multi-canal registrades en temps real; Part VI - Epíleg, on presentem les conclusions finals, delimitem les perspectives futures, i incloem annexos. / Vitale, R. (2017). Novel chemometric proposals for advanced multivariate data analysis, processing and interpretation [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90442 / TESIS
859

Specifický cementový kompozit na bázi druhotných surovin s důrazem na trvanlivost / Specific cement composite based on secondary raw materials with emphasis on durability

Figala, Petr January 2018 (has links)
Nowadays the attention to the utilization of secondary raw materials as a component of building materials is being paid to in the Czech Republic and in the world. This thesis deals with possibilities of using secondary raw materials as partial cement substitutes in industrial floors. The aim of this thesis is to verify the influence of cement substitution amount with secondary raw materials and their fineness of grinding on the properties of the floor surface in time and on its structure. On the basis of the acquired knowledge, the influence of the pre-treatment of the secondary raw material on the properties of the floor ceiling with an emphasis on the economic aspect was assessed. After evaluating the results, some substitution of cement in the floor screed with secondary raw materials is beneficial. The significant influence of more intensive milling of the floor screeds base on the parameters of the final floor screed was not confirmed. It seems, that it is possible to achieve very good results even when using secondary raw materials with a lower percentage of fine particles. This brings together the economic benefits of lowering the cost of a lower dose of expensive cement by using cheaper secondary raw materials, because pre-treatment of such materials does not require the use of a large amount of energy.
860

Optimalizace složení matrice cementotřískových desek při využití alternativních surovinových zdrojů / Optimisation of cement-bonded particleboard matrix composition by using alternative raw material sources

Roháček, Lukáš January 2018 (has links)
The diploma thesis deals with possibility of utilization raw materials from alternative sources for production of cement-bonded particleboards. In theoretical part the possibilities of modifying composition of cement-bonded slabs with emphasis on their matrix are discussed in detail. On basis of the findings and their evaluation, waste from the formatting of cement-bonded particleboards, micronized limestone, heat sink and high temperature fly ash were selected to the composition modification. The mentioned raw materials were analyzed and subsequently tested as substitutes for the matrix of cement-bonded particleboards in the experimental part. The properties of the proposed materials were tested even in the longer term, including the microstructure.

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