No description available.

No description available.

No description available.

Biogenic structures can impart important information regarding animal behaviors and depositional conditions at the time of colonization including: sedimentation rate, current velocities, distribution of food resources, oxygenation, salinity, and temperature. This thesis utilizes various ichnological subdisciplines to build upon these underlying ichnological principles. Neoichnology is a newly emerging field that can provide invaluable information about modern and ancient organisms. Burrowing activities of a population of deposit-feeding, freshwater Limnodrilus and Tubifex is found to produce biogenic graded bedding. Similarly, the burrowing activities of Euzonus mucronata are studied in relation to the trace fossil Macaronichnus segregatis, which displays mineralogical segregation between the burrow infill and mantle. The process of grain partitioning was assessed using videographic analyses of ingested and excreted grains by these deposit-feeding polychaetes, which selectively ingest felsic grains through en-masse feeding in felsic-rich locales. Macaronichnus is an important trace in ancient deposits of nearshore settings; however, since its inception, the genus had not been formally diagnosed. Accordingly, a unique approach to classification of these traces was undertaken, using grain sorting and collective morphology as ichnotaxobases, in addition to the diagnosis of a new, related genusHarenaparietis. In the Permian Snapper Point Formation of SE Australia, a new ichnospecies of Piscichnus was diagnosed and interpreted to reflect fish or cephalopod feeding via hydraulic jetting into the substrate in search of infaunal food sources. The delineation of trace fossils through ichnotaxonomy provides a basis for identifying trace fossil suites, which can be interpreted through ichnofacies analysis. Subtle ichnological and sedimentological attributes of deltaic strata in the Viking Formation permits the identification of wave-influenced and mixed river- and wave-influenced deposits in the Hamilton Lake and Wayne-Rosedale-Chain areas of Alberta, Canada, respectively. Facies analysis combined with the identification of palimpsest stratigraphic surfaces led to the identification of transgressively incised shoreface deposits at Hamilton Lake. Examples of palimpsest ichnofossils from the Hamilton Lake area and from other strata are used in an assessment of soft-, stiff- and firmground suites. This study revealed the importance of substrate properties, environment, stratigraphy and processes leading to the formation and expression of allocyclic and autocyclic surfaces.

No description available.

Arsenic contamination of groundwater associated with mining operations is a widespread problem across the globe. The release of arsenic (As) into the environment occurs naturally by oxidation of exposed sulfide minerals. In the case of gold ores, the mining and beneficiation may also produce As-bearing wastes and this can accelerate the natural mechanisms of As mobilization. The Bakyrchik is the largest gold deposit in Kazakhstan and one of the largest in the world. Gold (Au) is dispersed in pyrite and arsenopyrite in the form of microscopic inclusions. Despite the fact that only 10% of gold ore has been mined to date, it has left behind a dangerous As-containing legacy. Speciation of As has been determined for samples from Bakyrchik to understand the post-processing environment and the mobility of arsenic in the mining-influenced area. As(III) and As(V) have been detected in water samples using HPLC-ICP-MS. The variability of As species across the narrow pH and Eh range indicates that biogeochemical processes can play a role in the speciation of As in water at the study site. In order to understand processes controlling As mobilization in water, the solid phase speciation of As in Bakyrchik sediments, soil, and metallurgical processing products has been investigated using XRD and EPMA. This revealed arsenopyrite, As-bearing pyrite, and their alteration products containing up to 25% As, iron oxides and oxyhydroxides (with up to 2.5% As), haidingerite, and calcium arsenate in studied samples. Sequential extraction demonstrated that in soil and sediment samples As is associated mainly with Al and amorphous Fe oxyhydroxides. Results suggest that the main mechanisms controlling As mobility in Bakyrchik are dilution with regional waters, adsorption onto iron and aluminium oxyhydroxides, and co-precipitation of dissolved As with alteration products of sulfide minerals. Assessment of As bioaccessibility through inhalation demonstrates its strong dependence on the mineralogy rather than on total As content of the solid samples. Calculated cancer and non-cancer risks of inhalation exposure imply that all samples are highly hazardous for human health. With the depletion of the oxide lode ore deposits, gold extraction is moving towards the mining of technologically difficult ores, such as those found at Bakyrchik. A new method of Au recovery from double refractory Au-As-bearing concentrates has been developed, allowing recovery of 97% of Au, and the conversion of up to 95% As into iron-arsenic alloy. Fe-As alloy can contain up to 40% As, and do not require further solidification/stabilisation prior to disposal. The method has been published as a patent with the Patent Office of the Republic of Kazakhstan. Quantitative phase composition of the Fe-As alloy, has been determined by EPMA, QEMSCAN, X-ray and neutron diffraction. Toxicity and solubility of Fe-As alloy in aqueous solutions have been characterised. High-temperature structural behaviour of Fe-As alloy and Fe$_{2}$As in inert atmosphere has been determined by $\textit{in situ}$ synchrotron XRD. Results of the study support the development of the new method as an efficient alternative for processing double refractory Au-As-bearing concentrates.

The influence of agronomic practices on forage production and chemical composition of an orchardgrass-bromegrass pasture mixture was studied at the Greenville Farm, Logan, Utah, during 1960-1964. The soil is a well drained Millville Silt loam that has about a one percent slope and occurs on an alluvial fan. It is high in potash, phosphorus and calcium and is alkaline having a pH of 7.9 to 8.2. Analysis of the clipping frequency showed that the yield of forage from four harvests was greater than from five harvests. This difference was greater on plots receiving high rates of nitrogen fertilization, and frequent irrigation. Nitrogen, phosphorus, calcium, copper, iron and zinc contents were lower with five harvests. Forage production increased significantly as the available moisture in the soil increased, producing the highest yields for the 5-day irrigation interval. Nitrogen, copper, iron and zinc in the foliage decreased and phosphorus and calcium increased with increasing soil moisture. On the contrary, potassium content did not show a specific trend with increasing soil moisture. Nitrogen fertilization increased the forage dry matter production significantly giving the highest yield for 200 pounds of applied nitrogen per acre per season. The percentage of nitrogen in harvested forage decreased up to 100 pounds per acre of applied nitrogen and slightly increased with 200 pounds. Calcium, iron and manganese contents decreased and zinc content slightly increased with an increase in the amount of nitrogen fertilization. On the other hand, phosphorus, potassium and copper contents did not show a consistent trend with increasing nitrogen fertilization. A difference was noted between the amount of forage produced for different years. However, there was a tendency of decreasing forage yield with increasing age of stand. Nitrogen and phosphorus contents increased and copper, iron and manganese decreased significantly with the increasing age of stand. Potassium, calcium, and zinc contents showed a gradual decrease with the age of forage but there was a fluctuating tendency in their content for different years.

Thesis (Ph. D.)--Mississippi State University. Department of Agricultural and Biological Engineering. / Title from title screen. Includes bibliographical references.

Šio darbo autorė Sigita Čiurlienė aptaria tarpusavio santykių aspektus ir jų demokratinę raišką; demokratinių santykių sampratą; demokratinių santykių kūrimo veiksnius. Svarbiuose Lietuvai dokumentuose akcentuojami demokratiniai santykiai. Žymūs mokslininkai tyrė ir aprašė tarpusavio santykius, tačiau pasigendama išsamių darbų nagrinėjančių tarpusavio santykių pobūdį. Šio tyrimo tikslas-išanalizuoti demokratinius santykius mokyklos bendruomenėje ir nustatyti veiksnius darančius jiems įtaką. Tikslui pasiekti buvo suformuluoti tokie tyrimo uždaviniai: mokslinės literatūros pagrindu atskleisti demokratinių santykių sampratą; ištirti mokinių ir mokytojų požiūrį į demokratinius santykius ir jiems įtakos turinčius veiksnius; nustatyti santykių tarp mokinių, mokytojų ir mokinių pobūdį, pateikti rekomendacijas. Tyrimo metodai: mokslinės literatūros analizė - demokratinių santykių sampratos analizavimui; mokinių apklausa – buvo sudarytos anketos, kurios padėjo atskleisti mokinių požiūrį į demokratinius santykius ir veiksnius darančius jiems įtaką; interviu – nustatyti mokytojų požiūrį į demokratinius santykius ir veiksnius darančius jiems įtaką; stebėjimas - santykių tarp mokinių, mokytojų ir mokinių pobūdžiui nustatyti. Remiantis literatūros analize, moksleivių ir mokytojų apklausa ir mokinių stebėjimu, buvo suformuluotos šios išvados: Mokslinės literatūros analizė atskleidė, kad demokratiniai santykiai yra grindžiami aktyviu dalyvavimu, pagrįsti abipuse pagarba, pasitikėjimu... [toliau žr. visą tekstą] / The master thesis of Sigita Čiurliene, deals with the issue of social relationship in school society and its democratic expression. It is an attempt to give a definition of social relationship and to show the main ways of its creation and development in learning environment. The concept of democratic relationship is emphasized in Lithuanian main documents. Famous scientists investigated and described social relationship but we are short of exhaustive works in this field. The author’s objective in this paper is to analyze democratic relationship in school community and to find out the main factors influenced this relationship. The main focus is to provide analyses of the following problems: determination of social relationship in school society; investigation of students’ and teachers’ attitude towards social relationship and different factors influenced it; analyses of the relationships between students and teachers and their nature. In accordance with the analyses of special literature, students’ and teachers’ interviews and observation of students there were made the following conclusions: analyses of scientific literature have disclosed that democratic relationship stipulated active participation based on two- way exchange with respect, trust, openness and it is of the same importance to all members of the society. Only in such learning environment students and teachers become partners. The empirical part of given analyses has disclosed that... [to full text]

[pt] Este trabalho investiga a formação de biofilmes sobre ligas de aço inoxidável S32750, conhecido como superduplex, por cepas de bactérias redutoras de sulfato (BRS) em circuito de teste, submetido a condições de vazão e temperatura constantes, utilizando como fluido de processo a água do mar sintética. As ligas de superduplex são geralmente empregadas em serviços cuja concentração de íons cloretos é alta. As BRS desempenham papel significativo nos processos corrosivos por pites em aços inoxidáveis. Foram elaborados corpos de prova em S32750 e em AISI 316, a título de comparação com a literatura, que foram expostos ao fluido de processo por 15 e 35 dias. Também foi avaliada a influência das características físicas da superfície e para isso foram testados três diferentes tratamentos superficiais nos corpos de prova antes de serem inseridos no sistema: jateamento com microsfera de vidro e polimento com pasta de diamante com grãos de 6 μm e 1μm. Foram realizados a quantificação das BRS sésseis e planctônicas, o teor de sulfetos totais produzidos, a quantificação dos ácidos orgânicos e sulfato depletado, a morfologia dos biofilmes, a rugosidade superficial, além da avaliação dos pites formados. Foram realizados ensaios abióticos (sem a presença de bactérias) a fim de avaliar a ação corrosiva do meio. / [en] The goal of this work is to determine the biofilm colonization on the surface of superduplex stainless steel S32750 by Sulfate Reducing Bacteria (SRB) in a flow loop at constant flow rate and room temperature, exposed to artificial sea water. The duplex stainless steel has been widely used as material for offshore applications due to their excellent corrosion resistance in chloride environments, compared with austenitic stainless steel. At high concentrations these sulfides are known to adsorb and catalyze anodic dissolution and hence facilitate pitting. The samples of S32750 were exposed to flowing conditions for 15 and 35 days. Other 316 stainless steel coupons were exposed under the same time in order to compare with superduplex. The physical and chemical characteristics of a solid surface affect biofilm formation in flowing systems. Surface roughness affects bacterial adhesion. The degree of surface roughness may well be a critical factor in biofilm development. Some coupons were ground and others were polished (6 μm e 1 μm - diamond paste). The bacterial cells were quantified using most probable number (NMP) method. It was also quantified the total sulfide, the organics acids and sulfate depleted. Biofilm morphology, surface roughness and pitting formation were explored.