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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.
101

Cr (VI)-Containing electri furnace dust and filter cake: characteristics, formation, leachability and stabilisation

Ma, Guojun 18 October 2006 (has links)
In South Africa, the ferrochromium industry produces approximately 100,000 t bag house filter dust and slurry, while the stainless steel industry produces 24,000 t of dust annually [17,39]. The toxic substances in these wastes potentially pose a threat to the environment and human health, especially Cr (VI) due to its toxic, carcinogenic, highly soluble and strongly oxidizing properties. Therefore, the existence and treatment of wastes from stainless steel and ferrochrome production remain a challenge and an issue of concern. The increase of environmental legislation globally and the trend towards sustainable development are drives for alternatives to landfill. In the present thesis, the characteristics, formation mechanisms, leachability and stabilisation of the Cr (VI)-containing electric furnace dust and filter cake were investigated using various techniques such as XRD, XRF, TG/DTA, XPS, SEM-EDS, FT-IR, Raman spectrometer and UV/Vis spectrometer. The electric furnace dust and filter cake are very fine particles. Stainless steel dust forms by the entrainment of charge materials, evaporation or volatilisation of elements and ejection of slag and metal by spitting or the bursting of gas bubbles. It was found that ferrochrome dust is formed by the ejection of slag and metals droplets from the electrode hole, the entrainment of charge materials, vaporisation as well as the formation and precipitation of compounds from vaporised species in the off-gas duct. Filter cake contains crystal phases (CaF2 and CaSO4 ) and metal rich amorphous phases. It is formed due to super saturation and precipitation. Leaching experiments on the wastes showed that Cr (VI) rapidly leaches out by distilled water. Bricks were produced by mixing wastes (stainless steel plant dust, ferrochrome dust and filter cake) and clay. The optimum sinter parameter was found to be 1100oC and 5 hours for a 50wt% SPD-50wt% AS mixture in the brick. The leachability of Cr(VI) is strongly influenced by the mass%CaO/mass%SiO2 ratio and alkali metal oxides content in the wastes. The emission factors from the stabilised wastes (SPD, FCD1, FCD2 and FC) are similar to those reported for the cement industry. Semi-dynamic leaching tests indicated that the predominant leaching mechanisms of chromium species are initial surface wash-off followed by matrix diffusion. / Thesis (PhD (Metallurgical Engineering))--University of Pretoria, 2007. / Materials Science and Metallurgical Engineering / unrestricted
102

Podnikatelský plán - italská pekárna / Business plan – Italian bakery

Hortová, Edita January 2011 (has links)
The main aim of this thesis was to create a business plan to open an Italian bakery and coffee bar and discover the viability of the plan. Thesis is divided into theoretical and practical part. The practical part is formed on basis of theoretical information that characterizes business, environment of business in the Czech and Italy and main points of structure of the business plan. The practical part is formed by own business plan. This part describes goals, marketing plan, financial analysis, SWOT analysis, risk analysis and supplement. In part of conclusion readers learns if the business plan will be suitable for implementation.
103

Pastelería Gluten 4 Free

Borda Málaga , Rodrigo Felipe, Lizárraga Cabrales, Diego Alejandro, Ortega Soto, Jazmin Patricia, Peña Pinto, Nadya Deborah 11 July 2020 (has links)
La idea de negocio consiste en atender la demanda del consumo de postres libres de gluten de un público que padece de celiaquía, el cual es un mercado poco conocido en el Perú. La población aproximada según la Asociación de Celiacos en el Perú es de 1%, por ello, este proyecto empresarial presenta la creación del negocio de la Pastelería Gluten 4 Free. Cabe resaltar, que esta idea surge como la respuesta a una necesidad no satisfecha, ya que los Celiacos no logran ubicar con facilidad tiendas con diversos postres libres de gluten como chocolates, brownies, pasteles, alfajores, entre otras y que sean enviadas a domicilio o consumidas en el propio local, cuyos precios son accesibles, de consumo saludable, y de un servicio de venta y postventa que satisfará al público. Al contar con un equipo de trabajo con experiencia en al rubro administrativo, financiero, logístico, recursos humanos y chef, se tiene una sólida base para hacer el negocio perdurable a través de los años. Por último, en los estados financieros se obtiene la sustentación de la sostenibilidad y escalabilidad del proyecto en el tiempo. Antes de terminar el año 5 se logra la recuperación de la inversión e incluso obtener utilidad neta. El método de financiamiento será a través de recursos propios, por lo que no requerirá la solicitud de préstamo a entidades financieras. Actualmente, se tiene previsto la inversión de cuatro accionistas por el importe de 19,544 soles, en caso un inversionista adicional desee invertir en el proyecto la inversión inicial de cada uno seria de 15,635 soles. / The business idea is to meet the demand for gluten-free desserts from a public that suffers from celiac disease, which is a little known market in Peru. The approximate population according to the Association of Celiacs in Peru is 1%, therefore, this business project presents the creation of the business of “Pastelería Gluten 4 Free”. It is worth noting that this idea arises as a response to an unsatisfied need, since celiacs are unable to easily locate stores with various gluten-free desserts such as chocolates, brownies, cakes, alfajores, among others, that are sent to their homes or consumed on site. These stores have accessible prices, healthy consumption, and a sales and after-sales service that will satisfy the public. By having a team with experience in the administrative, financial, logistical, human resources and chef areas, we have a solid base to make the business last through the years. Finally, in the financial statements we obtain the support of the sustainability and scalability of the project in time. Before the end of year 5, the investment is recovered, and even net profits are obtained. The financing method will be through own resources, so it will not require the application of loans to financial institutions. Currently, four shareholders are expected to invest 19,544 soles in the project. If an additional investor wishes to invest in the project, the initial investment of each will be 15,635 soles. / Trabajo de investigación
104

Rizika založení malého podniku / Risks of starting a small business

Surá, Tereza Unknown Date (has links)
This master thesis is concerned with the business plan for the establishing of a small cake studio. Based on the critical analysis of the risk, marketing research and market analysis will be suggested a plan, by which would be possible to establish the small cake studio.
105

Conversion of Rapeseed Cake Into Bio-Fuel in a Batch Reactor: Effect of Catalytic Vapor Upgrading

Giannakopoulou, Kanellina, Lukas, Michael, Vasiliev, Aleksey, Brunner, Christoph, Schnitzer, Hans 01 March 2010 (has links)
The objective of this work is the development of a method for the catalytic conversion of biomass into liquid products, which could be further treated for the production of bio-fuels. Rapeseed cake was used as a source of biomass, while H-ZSM-5 and H-Beta zeolites were used as catalysts. The process was carried out at 400 °C, in a batch reactor with two configurations. In the first configuration, produced vapors were condensed and collected. In the second configuration, a fixed bed catalytic vapor upgrading section was added into the reactor. The conversion of the rapeseed cake resulted in the formation of two liquid phases (an organic and an aqueous phase), gases and a solid residue. The highest organic liquid phase yield was attained on H-ZSM-5 zeolite at the use of the vapor upgrading section. The aqueous phases contained a mixture of water-soluble substances, mainly N-heterocyclic compounds. The catalyst regeneration studies showed that H-ZSM-5 zeolite in both the reactor and the vapor upgrading section was more stable than H-Beta.
106

Comparison of Pre- and Post-treatments of Sugarcane Industry By-products to Increase Biomethane Production

Huang, Baitong January 2020 (has links)
Even though the Brazilian ethanol and sugar production system (based on sugarcane industry) have been providing large amounts of bioenergy, the extensive amounts of organic wastes generated cannot be ignored when it comes to sustainability. Using these biomasses to produce biomethane through anaerobic digestion has been proven as a promising way to tackle this issue. This study investigated the biomethane potential of the co-digestion of these biomasses: SF (sugarcane straw : filter cake = 8:2), SFV (sugarcane straw : filter cake : vinasse = 1:4:45), and D (digestate separated from AD of SFV). Three treatments autoclaving (AU), alkaline (AL) treatment using 6% (w/w) NaOH and the combination of these two (AUAL) were then conducted on SF and SFV as pre-treatments; on D as post- treatments. In the biomethane potential tests of untreated material, the highest methane yield was achieved by SFV with 275.28 ± 11 N ml CH4/g VS, followed by SF with 223.25 ± 10 N ml CH4 g-1 VS, substrate D also resulted in a methane potential of 144.69 ± 2 N ml CH4 g-1 VS. As pre-treatments, AL and AUAL both showed increase in methane yield (between 36.0% and 49.1%) and methane production rate. As post-treatments, AU, AL and AUAL showed distinctive results in methane production, with 33.8%, 99.8% and 128.8% increase, respectively. In comparison with pre-treatment, post-treatment showed a better performance in increasing methane production. The following feeding experiments performed in continuous stirred-tank reactors showed that AL treatment led to an average of 248% increase in methane yield. / Sugarcane waste: towards a zero C emission in the Brazilian bioenergy sector
107

An Examination of the Instability and Exploitation in Congo From King Leopold II's Free State to the 2nd Congo War

Beal, Baldwin 01 December 2014 (has links)
This thesis will analyze the Congo from King Leopold II's Free State to the 2nd Congo War. After a thorough investigation of the colonial period, this thesis will analyze the modern period. This thesis contends that the underdevelopment of the Congo, and its continuing warfare and poverty are the consequences of an exploitative colonial history. To be sure, King Leopold II of Belgium created the template for administering the Congo through the installation of concessionary companies that were more interested in harvesting huge profits than creating the conditions for a self-sustaining Congolese economy. Indeed, the policies implemented by King Leopold not only created the framework for the exploitation of the Congo after the cessation of the Free State, and set the stage for Congo's current state of instability of warfare.
108

High fructose corn syrup in shortened cakes with modified corn starch additives

McCullough, Maris Ann Palmer January 1985 (has links)
Cakes were prepared with high fructose corn syrup (HFCS) at 0, 50, and 75% replacement for sucrose by weight of sugar and pregelatinized cross-bonded waxy corn starch added at 0, 0.5, and 1% by weight of flour. The water was adjusted to allow for the moisture content (literature value) of the syrup. Cakes were tested freshly baked, after 3 days of room temperature storage, and after 14 and 45 days of frozen storage (-16°C). The pH, specific gravity, and sugar composition by HPLC were determined for the cake batters. Baked cakes were evaluated for moisture content, volume, and crust and crumb color. Photographs were taken to record the overall appearance. Sensory evaluation of crust and crumb color, moistness, tenderness, flavor, and overall acceptability were completed on all variations after each storage time. The HFCS level and storage time were significant variables. The addition of starch had no effect on the quality of the cakes. Acceptable cakes were made at all levels of HFCS replacement for sucrose. Crust and crumb color were significantly (P < 0.0001) darker and volume was significantly (P < 0.0001) lower for cakes containing HFCS, however, there was little difference in cakes made with the two levels of HFCS (SO and 75%). Storage did lower the overall quality of the cakes, but not significantly in all cases. Moisture content of the cakes stored for 14 days was equal to that of freshly baked cakes. Crust and crumb color continued to darken slightly with storage. A satisfactory cake suitable for frozen storage may be prepared using HFCS. / M.S.
109

Factors Contributing to Trimethylamine Generation from Limed and Polymer Conditioned Sludges

Schneekloth, Eric John 27 June 2007 (has links)
Trimethylamine, (CH3)3N, (TMA), odors are often associated with limed and polymer conditioned sludges. This odor has a fishy smell and can be a nuisance to the community surrounding a wastewater treatment plant or land application site. Several factors are thought to determine the amount of TMA generated from limed biosolids. These are, the presence of cationic polymer, the polymer dose, the time between addition of polymer and lime stabilization, shear imparted on the sludge in the dewatering process and dewatered cake solids concentration. All of these were investigated in this study. The results showed that TMA could be generated from sludge that did not contain polymer but the concentrations were low compared to sludge conditioned with cationic polymer. As the polymer dose increased, the TMA increased. Shear also showed to play an important role for TMA production. In addition to higher shear increasing the polymer demand, shear in itself can increase TMA generation. However, the most important factor in generating TMA was the time between conditioning and liming. If this time was minimized, little TMA was produced, even at high polymer doses. Data also suggests that methanogens play an important role in the breakdown of TMA. / Master of Science
110

Aufbereitung von Athabasca Ölsand

Tewes, Elisabeth 11 December 2015 (has links) (PDF)
Gegenstand dieser Arbeit ist die Entwicklung und Untersuchung eines Aufbereitungsprozesses zur Gewinnung von Bitumen aus kanadischem Athabasca Ölsand, der im Tagebau gewonnen wurde. Es wird ein mechanisch-thermisches Verfahren zur Fest-Flüssig-Trennung eingesetzt. Dabei handelt es sich um vier Schritte: (1) Suspendierung des Ölsandes mit den organischen Lösungsmitteln, Toluol und n-Heptan, (2) Filterkuchenbildung, (3) Waschung des Filterkuchens mit Wechsel der Waschflüssigkeiten (gradierte Waschung) und (4) Dampfbeaufschlagung. Der Prozess stellt eine Alternative zur herkömmlichen Heißwasser-extraktion des Ölsandes dar. Die Nachteile der Heißwasserextraktion sind ökologische Probleme, ein hoher Energie- und Frischwasserbedarf. Die Ziele des Alternativprozesses sind die Minimierung des Wasser- und Energiebedarfs, Vermeidung schädlicher Abfallstoffe sowie die Maximierung der Bitumenausbeute. Als Produkte sollen feststofffreies Bitumen und rückstandsfreier, deponierbarer Feststoff gewonnen werden.

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