The master ‘s thesis deals with the studying behavior of nuclear reactors cooled by liquid salts and with application of liquid salts for IV. Generation of nuclear reactors. For the use of liquid salts, it’s necessary to change the concept of the structure of nuclear reactors. There are new ways to use new fuel in a liquid state. Each salt compound or a set thereof is original in its nature. Therefore, it is necessary to consider a suitable compound for the purposes employed. These points are discussed in the theoretical part. The thesis examines particularly chloride salts, with which there is not much experience. The practical part monitors and verifies the nuclear properties of chloride salts, in our case it is a solid-state chloride sodium chloride’s compound. In addition to the experimental measurement, the MCNP simulation program is used also.

Master of Science / Department of Civil Engineering / Kyle Riding / Some limestone coarse aggregate in concrete pavement can break down under repeated freeze-thaw cycles. Application of rock salt may increase the severity of exposure conditions because of trace compounds, such as calcium sulfate, in rock salt. Subsequently, limestone aggregate in concrete was subjected to freeze-thaw cycling in two methods: salt-treating the aggregate before batching concrete, and half-immersing concrete specimens in rock salt solution during freeze-thaw cycling. Concrete and saw-cut limestone specimens were also subjected to wet-dry cycles in varying salt solutions to examine the influence of trace compounds in rock salt. Freeze-thaw test results indicate that the test methods used were not severe enough to determine if a limestone aggregate was durable or not. The wet-dry testing was also not severe enough to determine the effects of trace compounds in salt solution.

Call number: LD2668 .T4 1979 C5266 / Master of Science

Master of Science / Department of Civil Engineering / Kyle Riding / Fly ash is a by-product of coal-fired power plants. This material can be used as a partial cement substitute in portland cement concrete. Use of fly ash can improve concrete durability as well as utilize an industrial by-product that would otherwise be discarded in landfills. However, research on fly ash concrete has shown that in some cases, concrete with high volumes of fly ash can have deicer salt scaling problems. Salt-scaling is the flaking of a concrete surface that when severe enough may result in lower skid resistance and service life of the concrete. In this study, concrete mixtures with six different fly ashes were tested in a laboratory using the ASTM C 672 standard. Curing compound, a wax-based coating sprayed on the fresh concrete surface to reduce evaporation, was used to compare the effects of curing on salt scaling of concrete containing high volumes of fly ash. Different variables measured were the type of fly ash, curing conditions, and total paste volume included in the mix. Results showed that curing compounds will improve the salt-scaling resistance of concrete containing a fly ash that only marginally exhibits salt scaling. However, the salt-scaling performance of concrete that contains fly ash from a source that performs poorly in ASTM C 672 is not markedly improved by using a curing compound. Additionally, results showed that salt-scaling resistance of concrete containing fly ash performs better when the total paste volume is not increased by the addition of fly ash to the mixture. The Kansas Outdoor Concrete Exposure Site (KOCE) at the Kansas State University Civil Infrastructure Systems Laboratory (CISL) was constructed to compare laboratory results to actual field conditions in the future. The site was developed based on experiences from the University of Texas-Austin outdoor exposure site and the CANMET exposure site in Ottawa, Canada. Alika silica reaction blocks were made to develop the procedure for future concrete durability testing at KOCE.

The origin of the Silverpit structure, UK North Sea has been contested since its discovery on seismic data in 2002. The Silverpit structure consists of a 3 - 4km central zone of deformation, which includes a conical uplift. This is surrounded by a series of ring faults up to a maximum diameter of 20km. Meteorite impact, evaporite withdrawal, pull-apart basin tectonics and halokinesis tectonics have all been suggested as possible origins. This thesis uses a multi-discipline approach to test these hypotheses and determine with certainty the origin of the Silverpit structure. Seismic interpretation of the Silverpit structure has highlighted that deformation in the central deformation zone and beneath the structure is comparable with other meteorite craters. However, the ring faults are comparable with other structures formed by regional evaporite dissolution and movement. Seismic interpretation on a regional, 3500km2 scale proved that the structure is unique and that salt movement was taking place at the same time as the Silverpit structure was created. Unusual diagenesis in the chalk beneath the Silverpit structure was identified as a result of the presence of both unusual geophysical and geochemical signatures. An anomalous sonic log response is attributed to a significantly decreased porosity at the base of the chalk unit. Anomalously negative stable oxygen isotopes were also found in the chalk beneath the structure. Unusually elevated heat flow is the likely cause of these irregularities. The evidence presented in this thesis leads to the conclusion that the origin of the Silverpit structure is in fact two-phase. Meteorite impact has lead to the formation of the central zone of deformation and conical uplift. It has also influenced the diagenesis of the chalk beneath the crater and created a more brittle chalk unit. Regional salt withdrawal is responsible for the formation of the ring faults, which have only formed in the meteorite impact induced brittle chalk. In simple terms, a meteorite impact formed the 3km crater and then salt withdrawal produced the circular rings during several million years after the impact.

The mineralocorticoid hormone, aldosterone, classically acts via the Mineralocorticoid Receptor (MR) to promote sodium transport in aldosterone target tissues, such as the kidney, thereby controlling long-term electrolyte homeostasis and blood pressure (BP). Aldosterone biosynthesis by the adrenal gland is regulated by a negative feedback loop called the Renin Angiotensin Aldosterone System (RAAS). The glucocorticoid cortisol (corticosterone in rodents), which has a very similar structure to aldosterone, shares with aldosterone an equal affinity for the MR. Typically, plasma cortisol levels are approximately 1000-fold higher than plasma aldosterone, and so the ligand specificity for aldosterone must be imposed on MR by other, non-structural, means. This specificity is important in order to retain electrolyte and BP balance within the control of the RAAS. The co-localisation of the enzyme 11β-Hydroxysteroid Dehydrogenase Type 2 (11β-HSD2) with the MR in aldosterone target tissues provides the MR with the aldosterone specificity it inherently lacks. 11β-HSD2 achieves this by converting active cortisol to its inactive 11-keto metabolite, cortisone (dehydrocorticosterone in rodents). In humans with the monogenetic Syndrome of Apparent Mineralocorticoid Excess (SAME), inactivating mutations in the HSD11B2 gene allows cortisol unregulated access to the MR. Resultant symptoms include severe hypertension and life-threatening hypokalemia. Individuals heterozygous for SAME display no overt phenotypes. However, some studies have associated SAME heterozygosity and loss-of-function polymorphisms within the HSD11B2 gene with essential and/or salt-sensitive hypertension in the general population. Targeted disruption of the Hsd11b2 gene in mice (Hsd11b2-/-) faithfully reproduces with all the major phenotypes of SAME patients. Mice heterozygote for the targeted gene (Hsd11b2+/-) have no phenotype and display a normal BP. In the present study, Hsd11b2+/- mice were used to explore the relationship between reduced 11β-HSD2 enzyme activity and salt-sensitive hypertension. On a high salt diet, Hsd11b2+/- mice were found to have increased BP and impaired natriuresis, compared to wild-type controls (Hsd11b2+/+). Further studies used pharmacological blockade of the Epithelial Sodium Channel (ENaC) and MR to ascertain the contributions of these pathways towards the observed phenotypes. These identified a deregulation of ENaC activity pertaining to an inability to regulate sodium appropriately. Investigations into the contributions of the RAAS and the Hypothalamus Pituitary Adrenal (HPA) axis have revealed valuable insights into their roles in this model. There is an implication that the RAAS has increased sensitivity in Hsd11b2+/-, further exacerbated by increased dietary sodium, and that the regulation of corticosteroids may also be altered. Novel observations have suggested that oxidative stress in response to a high salt diet could also be involved, as a study administering an antioxidant drug in conjunction with a high salt diet prevented the manifestation of a phenotype in Hsd11b2+/-. Finally, the generation of a floxed Hsd11b2 targeting construct for tissue-specific deletion of 11β-HSD2 will allow future studies into the contributions of specific 11β-HSD2 expression sites (such as the kidney) towards the phenotypes of both homozygous and heterozygous mice.

This study develops techniques for the preparation and counting of testate amoebae for Holocene sea-level reconstructions. In addition, this study provides a ~3000 year relative sea-level reconstruction for south Hinnøya in the Vesterålen islands off mainland Norway, adding new data to a poorly defined period of the Holocene sea-level history of north-western Norway. This is important to quantify rates of glacial-isostatic adjustment (GIA), to refine GIA models, and to establish baseline (pre-industrial) rates of relative sea-level change. Surface sediments from two salt marshes (Storosen and Svinøyosen) in south Hinnøya are used to assess the effects of using different preparation procedures and count totals when analysing for testate amoebae. Analytical efficiency can be improved upon by using a mild alkali, chemical disaggregant (5 % KOH) to break up fibrous salt-marsh sediment and concentrate tests prior to counting. A count total of 100 individuals, rather than 150, can be used to make time gains with little or no effects on assemblages. Training sets of salt-marsh surface testate amoebae, foraminifera and elevational data are established for the two field sites. For testate amoebae, species – elevation relationships are constructed using regression modelling and applied to downcore fossil samples using a transfer function to derive estimates of sea level for the past ~100 years. The greater water depths reconstructed between ~3000 and ~100 years ago are not covered by modern foraminiferal training sets and are therefore estimated qualitatively from the fossil foraminiferal assemblages supplemented by information derived from fossil molluscs. Chronology is based on a combination of AMS14C, 210Pb, 137Cs and a suite of geochemical markers. At south Hinnøya, sea level has been falling at a rate of ~0.5 mm yr-1 over the last 3000 years.

<p>This thesis uses results of systematic numerical models to argue that externally inactive salt structures, which are potential targets for radioactive waste disposal, might be internally active due to the presence of dense layers or blocks within a salt layer.</p><p>The three papers that support this thesis use the Gorleben salt diapir (NW Germany), which was targeted as a future final repository for high-grade radioactive waste, as a general guideline.</p><p>The first two papers present systematic studies of the parameters that control the development of a salt diapir and how it entrains a dense anhydrite layer. Results from these numerical models show that the entrainment of a dense anhydrite layer within a salt diapir depends on four parameters: sedimentation rate, viscosity of salt, perturbation width and the stratigraphic location of the dense layer. The combined effect of these four parameters, which has a direct impact on the rate of salt supply (volume/area of the salt that is supplied to the diapir with time), shape a diapir and the mode of entrainment. Salt diapirs down-built with sedimentary units of high viscosity can potentially grow with an embedded anhydrite layer and deplete their source layer (salt supply ceases). However, when salt supply decreases dramatically or ceases entirely, the entrained anhydrite layer/segments start to sink within the diapir. In inactive diapirs, sinking of the entrained anhydrite layer is inevitable and strongly depends on the rheology of the salt, which is in direct contact with the anhydrite layer. During the post-depositional stage, if the effective viscosity of salt falls below the threshold value of around 10¹⁸-10¹⁹ Pa s, the mobility of anhydrite blocks might influence any repository within the diapir. However, the internal deformation of the salt diapir by the descending blocks decreases with increase in effective viscosity of salt.</p><p>The results presented in this thesis suggest that it is highly likely that salt structures where dense and viscous layer/blocks are present undergo an internal deformation processes when these dense blocks start sinking within the diapir. Depending on size and orientation of these blocks, deformation pattern is significantly different within the diapir. Furthermore, model results applied to the Gorleben diapir show that the rate of descent of the entrained anhydrite blocks differs on different sides of the diapir. This suggests that if the anhydrite blocks descent within the Gorleben diapir, they initiate an asymmetric internal flow within it.</p>

When fires occur in domestic or commercial buildings it is the smoke from the fire that leads to far more injury and death than the heat produced from the flames. Understanding the movement of smoke within the fire compartment and through openings in the enclosure is critical for designing buildings to prevent fire fatalities. Prediction of the movement of smoke is a complex phenomenon and is a continued focus of research throughout the world. Work has been conducted in the past on the exchange flow rates through vertical openings, but very little has been done on horizontal ceiling openings. Current smoke transport calculations are most often carried out using standard vent flow models that do not accurately take in to account the buoyancy component of the flow. The fire zone model BRANZFire was developed with a ceiling vent flow algorithm based on the work of Cooper who found there was very little data on which to base his predictions. This report aims to provide additional experimental data on exchange flow rates through horizontal ceiling openings through the use of saltwater modelling and compare this to the work previously undertaken by Cooper. Taking measurements of fire phenomena in hot and smoky environments can be difficult and expensive because the sooty environment and high temperatures involved can damage equipment and make taking accurate readings a challenge. Herein this problem is overcome through the use of a saltwater analogue system to model the conditions in a real fire scenario. The density difference created by a fire between the hot fire gases and the ambient air is replicated by using fresh and saltwater. The orientation of the experiment is inverted compared to the real life scenario as the saltwater which has the higher density is added to the fresh water. The saltwater is injected from a source on the ‘floor’ of the compartment into a tank of fresh water which generates a buoyant plume that ‘rises’ to the ceiling forming a distinct upper layer. Fluid in this layer exchanges with the ambient fluid through the ceiling opening. The saltwater is dyed and Light Attenuation (LA) is used to discern the density of the fluid and hence the amount of mixing that has occurred. This can then be used to determine the amount of exchange flow through the ceiling vent. An integral model for the descent of the interface between the hot smoky zone and the cool ambient zone has been developed and was found to perform well when compared with the saltwater experiments and another predictive model developed by Turner and Baines. The model was then developed further using mass conservation conventions to calculate the exchange flow through the ceiling opening. The exchange rate through the ceiling opening was calculated and was found to compare well with Cooper’s algorithm when an equivalent fire size of 323 kW was used but differed significantly when a fire twice this size was considered. It was found that Cooper’s method did not adequately take into account the difference in fire sizes as the exchange flow predicted was almost identical between fire sizes for a particular ceiling vent. The implications of this are that the exchange, and hence the mixing and the amount of smoke, may be under predicted using larger fires in BRANZFire and this could lead to non-conservative design.

Artificially aged and non-aged seeds of 22 grain sorghum (Sorghum bicolor L.) F₁ hybrids and their F₂ and F₃ generations were evaluated for germination salt tolerance. Six of the hybrids, along with their F₂ and F₃ generations, were tested for emergence salt tolerance. Effects of seed production environments on germination salt tolerance were also studied using F₂ generations of 12 sorghum hybrids produced under full-season irrigation, limited irrigation, and double-cropping conditions. Germination tests were conducted in a growth chamber, on trays, while the emergence test was conducted in a greenhouse in flats filled with sand. The experiments were conducted under non-saline and saline conditions in randomized complete block designs. Artificial seed aging resulted in significant reductions in germination percentages under both non-saline and saline environments. The overall mean reduction in germination caused by seed aging was more than twice as much under salinity stress as under the non-stress conditions (48 vs. 17%), indicating differential effects of salinity on different quality seeds. Entries that appeared to be resistant to seed aging also had higher germination percentages under salinity stress. Seed production environment influenced germination performance in both non-saline and saline environments. The overall mean germination percentages of sorghum seeds produced under three different field environments were significantly different from one another. Significant differences were observed in germination and emergence percentages within F₁, F₂, and F₃ generations. Except for the F₁ entries, however, emergence index differences within the F₂ and F₃ generations were not significant. Correlations between germination and emergence percentages in the non-saline and saline treatments were generally nonsignificant. This suggests that germination and emergence responses of sorghum may vary under different salinity levels and different environments.