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This thesis is focused on determining the hydromechanical characteristics of clay suspensions, permeability and compressibility, where is the effective stress, the concentration of suspension and is the permeability. Because the compressibility or permeability can't be measured directly, I use Darcian mechanics of two-phase systems to compute the characteristics I wanted from a well- measurable quantities, measured in appropriate experiments. Work has been solved with the support of the project : Hydromechanical characteristics of clay suspensions. The first part deals with a mineralogical characteristics fylosilicates, characterization of kaolin deposits in the Bohemian Massif, physical chemistry of colloidal systems, electric double layers and electro kinetic potential. Experimental section follows later, which proceed from the assumption that the same concentration of kaolin suspension and an identical colloidal state, exposed to the same pressure-temperature conditions, exhibit the same values of hydro mechanical characteristics such as their evolution in time can be described as a continuous function. As the model, I chose the coagulated kaolin suspension. Coagulation are achieved by adding weight percent of solids . Suspension settles in a vertical cylinder of high with an inner diameter of , which...

Moisture in a sandstone body plays a notable role in hydrological, weathering, biological and other processes. Knowledge about presence and movement of moisture within porous medium of natural sandstone exposures is, however, rather limited. Aim of the doctoral thesis was thus to quantify selected moisture characteristics of several natural sandstone exposures in Český ráj (Czech Republic). According to long-term logging, mean annual temperature at studied areas was between 8.5 řC to 11.5 řC, mean annual relative humidity was between 73 % to 85 %. Deforested area was found warmer and drier and amplitude of the values was higher there than at the forested areas. Values of water content (more than 400 measurements) and suction (more than 150 measurements) of the exposures including their spatial-temporal changes were obtained. Mean volumetric water content in zone from the sandstone's surface to 12 cm depth was from 3 % to 10 % and mean suction in depth 2-12 cm was from 2 kPa to more than 130 kPa. Using uranine powder coloring, spatial distribution of moisture near the sandstone's surface was visualized repeatedly for the first time. The coloring divided the surficial area of the sandstone into capillary (wet) and diffusion (dry) zone. The sharp transition between the two zones was represented by...

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Irrigated agriculture is the largest user of freshwater in a world experiencing increased water scarcity and water demands. Variable rate irrigation (VRI) aims to use water efficiently in crop production, resulting in good yields and water conservation. With VRI, the grower is able to employ custom irrigation rates for different parts of a field. Adoption of VRI has been limited due to the complexity of matching irrigation to spatiotemporal crop water needs and the cost/benefit economics of VRI equipment. The goal of this study was to quantify spatiotemporal variability of VWC in a field that has uniform soil type and discuss the driving factors that contribute to that variability. Soil samples were acquired at 66 and 87 locations during the 2019 growing season at two study sites. Soil samples from 32 and 48 locations within each study site were selected to be analyzed for soil texture properties. The USGS Web Soil Survey was also referenced. Both, the USGS data and the data collected for this project showed very uniform soils across both fields. The objectives of this study were i) to show variability of VWC within fields that contain uniform soil texture using univariate Local Moran’s I (LMI) and ii) to compare static VRI zones based on spatial patterns of readily available field data that might serve as surrogates for VRI zones created from measured variation of soil volumetric water content (VWC). Management zones created using readily available field data had reasonable correlations with VWC. In both study sites, elevation was found to be the best variable for delineating VRI zones that imitate measured VWC.

Bostadsbristen ökar i samhället och många byggföretag vill hitta en lösning som gör att det går att tillverka snabbare, billigare och säkrare byggnader. Att bygga moduler med trästomme är en lösning men användning av trä kräver särskilda kunskaper när det gäller brandskydd. Att skydda trästomme med gipsskivor kan vara en metod för att öka brandsäkerheten. Syftet med studien är att undersöka om Vida Building AB kan byta ut den bärande väggkonstruktionen i deras volymelement där reglarna skyddas av två gipsskivor av typ A med tjockleken 12,5 och en plywoodskiva med tjockleken 12,5 mm, mot en skiva av märket Fermacell, en så kallad fibergipsskiva. Bärförmågan har beräknats efter 60 minuters brand i väggkonstruktionen när gips-och plywoodskivor bytts mot skivor av Fermacell. Bestämning av bärförmågan hos konstruktionen gjordes med hjälp av två beräkningsmodeller. Resultatet visar att det går att använda en Fermacell skiva på 18 mm om reglarnas dimensioner ökas från 45x95 mm till 45x120 mm eller till 45x145 mm. Alternativt kan en bärförmåga motsvarande den för nuvarande konstruktion erhållas om två skivor av Fermacell med tjockleken 12,5 mm används.

Bench and pilot scale determinations of the volumetric oxygen transfer coefficient, K_La, were performed on an improved A²/O biological nutrient removal (BNR) pilot plant. Effluent from a full scale primary clarifier, used as pilot plant influent, was found to have an alpha (ratio of process to clean water K_La) of 0.71 as determined in a 21 liter bench scale reactor and an alpha of 0.332 as determined in a 0.45 m³ aeration basin of the 2.4 m³ pilot plant. Alpha of a 1:1 mixture of primary clarifier effluent with pilot plant return activated sludge was determined to be 0.94 at bench scale and 0.71 at pilot scale. An assay of alphas through the initial non aerated treatment zones of the pilot plant using the bench scale reactor indicated that alphas peaked in the effluent of the first anaerobic zone (alpha equal to 1.01) and were lower in the second anaerobic zone and first anoxic zone. An assay of alphas in the three pilot plant series sideline aeration basins indicated that alpha was maximum in the first aeration basin (alpha equal to 0.905) and were lower in the second and third aeration basins (0.716 and 0.661 respectively). A consistent increase in average surface tension was noted from the first to second to third aeration basins, however the differences were not statistically significant. A comparison of pilot plant alphas determined in the first aeration basin following anaerobic nominal hydraulic retention times of 0.0, 0.21, 0.43, and 0.64 hours yielded alpha values of 0.71, 0.94, 0.64, and 0.74 respectively. Like the assay using the bench scale reactor, the alpha values at pilot scale peaked following treatment in only one anaerobic zone (nominal HRT of 0.21 hours). The study concludes that short exposures in an initial anaerobic reactor as required for biological phosphorus removal may benefit oxygen transfer efficiency through increased alphas, however the benefits of long periods of anaerobic reaction time (over 0.43 hours) are uncertain. / Master of Science

La démarche « matériaux numériques », développée au CEA Le Ripaut, consiste à optimiser numériquement une structure, à l’aide de codes de calcul permettant de réaliser des expériences numériques, afin de répondre le plus précisément possible à un cahier des charges. La mise en œuvre de ces structures optimisées, aux formes pouvant être complexes, n’est parfois pas réalisable avec les procédés de fabrication actuels. Cependant, la progression rapide de l’impression 3D semble maintenant pouvoir concrétiser cette démarche. Le but de cette thèse est d’étudier cette faisabilité de fabrication, à travers une application concrète : l’optimisation des récepteurs volumétriques des Centrales Solaires Thermodynamiques (CST).Actuellement, la conception de ces récepteurs en Carbure de Silicium (SiC) est restreinte par les techniques existantes de fabrication, et leurs morphologies se limitent donc principalement à des mousses ou des canaux parallèles. Or, ce type de structure ne permet pas d’exploiter tout le caractère 3D proposé par les récepteurs, en raison notamment d’une absorption trop hétérogène du rayonnement solaire dans le volume. Dans ce travail de thèse, afin de rechercher la répartition de l’absorption la plus homogène possible dans l’ensemble du volume, de nombreuses structures aux formes variées sont générées virtuellement. Une simulation de l’éclairement solaire reçu est réalisée sur l’ensemble de ces structures, grâce à un code de calcul développé spécialement pour cette application, permettant ainsi d’en retenir trois répondants au mieux aux critères du cahier des charges. Ces structures potentiellement optimisées ont ensuite été fabriquées en SiC par impression 3D, par un procédé de projection de liant sur lit de poudre. Elles ont été ensuite testées sur un banc d’essai expérimental du laboratoire PROMES, reproduisant les conditions d’une CST. Les résultats ont montrés que ces structures, aux formes totalement différentes de mousses ou de canaux parallèles, sont capables de produire au maximum de l’air à 860°C en sortie de récepteur, et avec des rendements énergétiques proches de 0,65. Enfin, un code de calcul thermique couplé conducto-radiatif, amélioré durant ce travail, a permis d’analyser ces résultats expérimentaux et servira pour les futurs travaux d’optimisation de la géométrie d’un récepteur. / The "numerical materials" approach, developed at CEA Le Ripaut, consists to numerically optimize a structure, by using calculation codes that allow to realize numerical experiments, in order to answer, as precisely as possible, to a set of specifications. The manufacturing of these optimized structures, whose shapes can be complex, is sometimes not feasible with current manufacturing processes. However, the rapid progress of 3D printing now seems to be able to concretize this approach. The aim of this thesis is to study this manufacturing feasibility, through a concrete application: the optimization of the volumetric receivers of Concentrated Solar Power Plants (CSP). Currently, the design of these silicon carbide (SiC) receptors is restricted by the existing manufacturing techniques, and their morphologies are therefore mainly limited to foams or parallel channels. However, this type of structure does not allow to exploit all the 3D character proposed by the receivers, due in particular to a heterogeneous absorption of solar radiation in the volume. In this work, in order to find the distribution of the most homogeneous absorption possible in the whole volume, many structures with various shapes are generated virtually. A simulation of the solar irradiance received is carried out on all these structures, thanks to a calculation code developed especially for this application, thus allowing to choose three of them, respondents at best to the criteria of the specifications. These potentially optimized structures were then manufactured in SiC by 3D printing, by a binder jetting process. They were then tested on an experimental test bench of the PROMES laboratory, reproducing the conditions of a CSP. Results showed that these structures, where their shapes are totally different from foams or parallel channels, are able to produce a maximum air temperature of 860°C at the output of the receiver, and with efficiencies close to 0.65. Finally, a conducto-radiative coupled thermal computational code, improved during this work, made it possible to analyze these experimental results and will be used for the future work of optimization of the geometry of a receiver.

Skeletal muscle injuries and muscle degenerative diseases pose significant challenges to the healthcare. Surgical interventions are restricted due to tissue availability, donor site morbidity and alterations to tissue biomechanics. Current cell-based therapies are hindered by low survival and long-term engraftment for the transplanted cells due to the lack of appropriate supportive microenvironment (cell niche) in the injured muscle. Therefore, there is a critical need for developing strategies that provide cellular and structural support in the regeneration of functional muscle. In the present work, a bioengineered cell niche mimicking the native skeletal muscle microenvironment has been developed for skeletal muscle regenerative engineering. It is hypothesized that the bioengineered scaffolds with appropriate structural and cell instructive properties will support myoblast alignment and function, as well as promote the myogenic responses in clinically relevant skeletal muscle injuries. The current work utilized a three-pronged approach to design biomaterial scaffolds to aid in skeletal muscle regeneration. In the first part, aligned poly(lactide-co-glycolide) (PLGA) fiber scaffolds mimicking the oriented muscle fiber microenvironment with fiber diameters of 335±154 nm (nanoscale), 1352±225 nm (microscale) and 3013±531 nm (microscale) were fabricated and characterized. Myoblasts were found to respond to fiber diameter as observed from the differences in cell alignment, cell elongation, cell spreading area, proliferation and differentiation. <i>In vivo</i> study demonstrated the potential of using microscale fiber scaffolds to improve myogenic potential in the <i>mdx</i> mouse model. In the second part, we designed, synthesized, and characterized an implantable glycosaminoglycan-based composite hydrogel consisting of hyaluronic acid, chondroitin sulfate and polyethylene glycol (HA-CS) with tailored structural and mechanical properties for skeletal muscle regeneration applications. We demonstrated that HA-CS hydrogels provided a suitable microenvironment for <i>in vitro</i> myoblast proliferation and differentiation. Furthermore, <i>in vivo</i> studies using a volumetric muscle loss model in the mouse quadriceps showed that HA-CS hydrogels integrated with the surrounding host tissue and facilitated <i>de novo</i> myofiber generation, angiogenesis, nerve innervation and minimized scar tissue formation. In the third part, we investigated the effects of PC12 secreted signaling factors in modulating C2C12 myoblast behavior. We showed that PC12 conditioned media modulated myoblast proliferation and differentiation in both 2D culture and 3D aligned electrospun fiber scaffold system in a dose dependent manner. We also demonstrated the biomimetic HA-CS hydrogel system enabled 3D encapsulation of PC12 cells secreting signaling factors and promoted survival and proliferation of myoblasts in co-culture. Further proteomics analysis identified a total of 2088 protein/peptides from the secretome of the encapsulated PC12 cells and revealed the biological role and overlapping functions of nerve secreted proteins for skeletal muscle regeneration, potentially through regulating myoblast behavior, nerve function, and angiogenesis. These set of experiments not only provide critical insight on exploiting the interactions between muscle cells and their microenvironment, but they also open new avenues for developing advanced bioengineered scaffolds for regenerative engineering of skeletal muscle tissues.<br>

This master thesis deals with modern technologies in graphic hardware and using their for general purpose computing. It is primary focused on architecture of unified processors and algorithm implementation via CUDA programming interface. Thesis base is to choose suited algorithm for GPU horsepower demonstration. Main aim of this work is implementation of multiplatform library offering algorithms for discrete volumetric data vectorization. For this purpose was chosen algorithm Marching cubes that is able to find surface of processed object. In created library will be contained algorithm runnable on graphic device and also one runnable on CPU. Finally we compare both variants and discuss their pros and cons.