L'étude concerne la prise en glace d'une paroi thermiquement contrôlée placée au sein d'une conduite dans laquelle se développe un écoulement turbulent d'air humide. L'ensemble des essais expérimentaux a été réalisé à partir du banc d'essai HUMIDE, soufflerie dédiée conçue au laboratoire et modifiée afin de suivre au cours du temps l'augmentation de masse de glace. Une analyse paramétrique de l'influence du taux d'humidité et de la vitesse de l'écoulement sur le dépôt de glace a été réalisée et, à partir de la mesure du flux global, il a été possible d'estimer les flux convectifs en présence de la glace. Les résultats soulignent clairement que les flux convectifs sont plus ou moins accentués en fonction de l'humidité.Une tentative de modélisation du mélange air - vapeur d'eau/glace, a été développée en partout de la théorie de nucléation et les différentes confrontations soulignent la très forte sensibilité des résultats vis-à-vis des conditions aux limites et de la modélisation. Au-delà de géométries simples comme la plaque, une géométrie caractéristique d'un échangeur a également été simulée notamment pour caractériser de manière qualitative les mécanismes de prise en glace de tels systèmes. / The study concerns the de-sublimation of a thermally controlled flat plate placedwithin a wind tunnel in which develops a turbulent moist air flow. A parametric analysis of the influence of humidity and the velocity of the flow on the ke formation was carried out and, from the measurement of global heat flux, it is possible to estimate the convective heat transfer with the presence of ice. The results show that the convective fluxes are more or less accentuated depending on the humidity. A solver to modeling of air - vapor/ice, was developed base on the theory of nucleation heterogeneous. Beyond simple geometry such as a flat plate, a characteristic geometry of a heat ex.changer was also simulated in particular to qualitatively characterize the ice formation mechanisms of such systems.

This dissertation details research aimed at the separation of Zr and Hf in the tetrafluoride form. Separation of ZrF4 and HfF4 was achieved using sublimation followed by desublimation. The separation involves the sublimation of the tetrafluorides in an inert atmosphere under controlled parameters. The sublimed mass (700 C to 800 C) diffuses into nitrogen which then flows across a water-cooled desublimer (annulus) with the aim of desubliming the one metal fluoride in preference to the other. This implies that separation was achieved in both the sublimer and the desublimer, due to differences in both the sublimation and desublimation rates. The aim was for the sublimer residue to be Hf-rich and the desublimer content to be Zr-rich. The Zr/Hf content was determined by means of ICP-OES analysis. It must be noted that the work reported in this thesis is based on only a first sublimation step. The reason for this is that the equipment used was on laboratory scale and that the mass collected from the desublimer was not sufficient to allow a second or third step to be carried out. Little information was available in the literature on the sublimation separation of Zr and Hf, especially in the fluoride form, most of it being sublimation under vacuum conditions. On an industrial scale, only vacuum sublimation of ZrF4 has been introduced into the industry, and no information was found for sublimation of ZrF4 in an inert atmosphere on an industrial scale. There was also limited information on the sublimation rate of ZrF4 or HfF4 in an inert atmosphere. In the process described in this dissertation, optimal temperature selection is crucial since low temperatures result in a low sublimation rate, and high temperatures not only increase the level of impurities in the sublimed product, but also increase the cost of construction material and energy consumption. The aim was to determine the experimental conditions, i.e. sublimation time, temperature and position on the desublimer, which will provide optimal separation conditions. These conditions must, however, be compared with the operating cost, as this will be higher at a higher temperature and for longer sublimation runs. / Dissertation (MEng)--University of Pretoria, 2018. / Chemical Engineering / MEng / Unrestricted

Cryogenic carbon capture removes CO2 and other pollutants from flue and waste stream gases produced from the combustion of fossil fuels such as coal, natural gas, and oil and the production of cement. A transient, 1-dimensional numerical model was developed to study the temperature profile within a counter-current surface CO2 desublimation-falling liquid or solid heat exchanger. Effects of desublimation heat and mass transfer as well as convective and conductive heat transfer relationships were taken into account. Experiments show that CO2 can be captured on a falling spherical particle when appropriate column operating conditions are met.

Submitted by Daniel Aranha (df_aranha@yahoo.com.br) on 2018-10-01T21:30:18Z No. of bitstreams: 1 Daniel_Aranha FGV-Dissertacao-Diversidade vFinal (1out2018) - Biblioteca.pdf: 971302 bytes, checksum: 1df325a5c82aa33b85b26ef2071a95b4 (MD5) / Rejected by Mayara Costa de Sousa (mayara.sousa@fgv.br), reason: Daniel, boa tarde. Alguns itens devem ser ajustados de acordo com as normas: 1. GETULIO não tem acento 2. Seu nome deve estar completo, sem abreviação 3. As palavras-chave do resumo/abstract devem ser separadas por ponto e virgula att, Mayara on 2018-10-05T19:32:07Z (GMT) / Submitted by Daniel Aranha (df_aranha@yahoo.com.br) on 2018-10-09T21:38:02Z No. of bitstreams: 1 Daniel_Aranha FGV-Dissertacao-Diversidade vFinal (1out2018) - Biblioteca.pdf: 971244 bytes, checksum: 094ef31f01f246465c5a4aa74b3e0f1e (MD5) / Approved for entry into archive by Mayara Costa de Sousa (mayara.sousa@fgv.br) on 2018-10-09T21:42:45Z (GMT) No. of bitstreams: 1 Daniel_Aranha FGV-Dissertacao-Diversidade vFinal (1out2018) - Biblioteca.pdf: 971244 bytes, checksum: 094ef31f01f246465c5a4aa74b3e0f1e (MD5) / Approved for entry into archive by Suzane Guimarães (suzane.guimaraes@fgv.br) on 2018-10-10T13:46:59Z (GMT) No. of bitstreams: 1 Daniel_Aranha FGV-Dissertacao-Diversidade vFinal (1out2018) - Biblioteca.pdf: 971244 bytes, checksum: 094ef31f01f246465c5a4aa74b3e0f1e (MD5) / Made available in DSpace on 2018-10-10T13:46:59Z (GMT). No. of bitstreams: 1 Daniel_Aranha FGV-Dissertacao-Diversidade vFinal (1out2018) - Biblioteca.pdf: 971244 bytes, checksum: 094ef31f01f246465c5a4aa74b3e0f1e (MD5) Previous issue date: 2018-09-12 / Diversidade nas organizações é um assunto amplamente estudado desde o final da década de 80 nos EUA, bem como a partir dos anos 2000 no Brasil. A maior parte destes estudos concentram-se na gestão da Diversidade, ou seja, uma perspectiva instrumental para as organizações maximizarem seus resultados ou desenvolverem vantagens competitivas. Por outro lado, há estudos Críticos que buscam entender o real impacto ou viabilidade das iniciativas de Diversidade nas organizações. Neste sentido, entendemos válido questionar o que representam o discurso e práticas organizacionais sobre Diversidade, com relação aos seus possíveis impactos sobre o indivíduo e, por consequência, sobre a sociedade. Neste trabalho, sob uma lente Crítica, em que utilizamos os conceitos de unidimensionalidade e dessublimação repressiva, de Marcuse; buscamos entender a relação entre aquilo que as organizações de forma explícita ou implícita buscam e determinam como metas em suas iniciativas relacionadas à Diversidade, com aquilo que os indivíduos e minorias tem a oferecer ou esperam de tais iniciativas. Analisamos a teoria que fundamenta os conceitos adotados pelas organizações em suas iniciativas sobre Diversidade, bem como pesquisamos o discurso e práticas seguidas por algumas organizações. Observamos que, (i) se por um lado é inegável que as iniciativas organizacionais representam um papel positivo, na medida em que pode reduzir injustiças sociais e desigualdade; (ii) do outro lado da mesma moeda, sob uma perspectiva Crítica, estas iniciativas tem um caráter retórico e pouco ou nada fazem para promover um comportamento que privilegie a diversidade de ideias, por exemplo. Pelo contrário, as práticas ou iniciativas organizacionais vinculadas à Diversidade acabam por representar a própria negação do diverso, estreitam a possibilidade de recusa e reforçam a unidimensionalidade. / Diversity in organizations is a widely studied topic since the late 80's in the US and since the 2000s in Brazil. Most of these studies focus on managing Diversity, that is, on an instrumental perspective for organizations to maximize their results or to gain competitive advantage. Conversely, there are argumentative studies that seek to understand the actual impact or viability of Diversity initiatives in organizations. In this sense, we consider that it is valid to question what organizational discourse and practices related to Diversity represent with respect to their impact on the individual and, consequently, on society. In the present paper, through a Critical lens and using the concepts of one-dimensionality and repressive desublimation by Marcuse, we seek to understand the relationship between what organizations explicitly or implicitly pursue and determine as their goals in the Diversityrelated initiatives, and what individuals and minorities have to offer to or expect from such initiatives. We analyzed the theory that supports the concepts adopted by organizations in their initiatives on Diversity, as well as investigated the discourse and practices applied by some organizations. We found that: (i) while on the one hand it is undeniable that these organizational initiatives play a positive role, insofar as they might reduce social injustice and inequality, (ii) on the other hand, from a Critical perspective, these initiatives have a rhetorical character and do little or nothing to promote behavior that favors the diversity of ideas, for example. On the contrary, Diversity-related organizational practices or initiatives eventually represent the denial of diversity itself, narrowing the possibility of refusal and reinforcing one-dimensionality.

在1960年為《理性與革命》寫的序言中，馬庫塞就曾提過所謂的「既定事實的力量」(the authority of established fact)，他認為「這是一種壓迫的力量」。 馬庫塞在其著作當中已多次提及所謂「既定的現實」(the established reality)，所意指的不外乎是身處於先進工業社會中的個體受到既定體制的壓迫(oppression)與制約，換言之，先進工業社會充滿著非解放的因素。 「現今，自由(freedom)與奴役(servitude)的結合變得『理所當然』(“natural”)，它已成為進步的一種手段(a vehicle of progress)。」此一論點馬庫塞在《愛欲與文明》一書中已提出，並在《單向度的人》一書中更充分地開展。 《單向度的人》的主要論點在於整體社會的意識受制於後期資本主義社會的結構，致使人們的思維無法覺醒，「現實即是合理」已經成為社會的正常看法，也就是大多數人皆依循此種模式過生活，而不去變革現狀(the status quo)。因為這一種消費與生產已形成人們的固定思維模式，即單向度的思維，由於人們不再反省現實社會的單向度現象，因此人們無法從單向度的現象中解放出來，大多數人仍處於不自覺的狀態，受到操控，社會中的成員共同架構出壓迫性的思維方式(oppressive mode of thinking)，「人的意識受制於社會的存在」，人心加重現實的趨勢致使「單向度」(one-dimensionality)的態勢逐步成形。