6,881 research outputs found
Detergency in Liquid CO2
No full textIn this dissertation we study Detergency in liquid Carbon Dioxide. Detergency is the cleaning performance of additives, surfactants in particular, in washing fluids. Liquid CO2 is under consideration, for environmental and toxicological reasons, to replace perchloro-ethylene as the solvent in textile dry cleaning technology. Inherent problems of such a transition were confronted with the methodology of chemical engineering design. The Basic Cycle of Design (BCD) approach was used as a pathway for designing a detergent. The BCD also establishes the structural framework of the thesis, which can, therefore, be read as records from a successful product engineering project, in which an effective detergent has been designed for a new dry cleaning solvent. The Dynamic Detergency Model (DDM), which succeeds to explain the role of surfactants in the washing operation, is used as a rational starting point for the design of a detergent in liquid CO2. According to this model, such a surfactant must be: sparingly soluble in the solvent, surface-active and able to form micelles in the solution. The different experiments carried out (solubility, interfacial-tension and dye solubilisation measurements), show that a number of molecules of the homologous polyoxyethylene/alkane series, generally described by the shorthand formula CiEj did indeed behave as surfactants and can be then considered detergents for liquid CO2. In the technical evaluation of the detergents, at laboratory as well as at semi-pilot scale, high washing performances were obtained. They are, indeed, as good for dry cleaning textiles as the present perchloro-ethylene (Perc) technology.Applied Science
Dr. Samuel Johnson and accounting
No full textJohnson\u27s knowledge of, and interest in, accounting may well have stemmed from his high regard for arithmetic. In several letters to Hester Maria Thrale and Sophia Thrale (daughters of Henry Thrale, Brewer and M.P. for Southwark), Johnson emphasized the importance of this subject. Many of the letters were repetitive, but the following extracts from April and July 1783, when Hester and Sophia were 18 and 12 years old respectively, present the flavor of his views
'Her Irish Heritage' : Annie M.P Smithson and autobiography
No full textThis paper examines some aspects of the work of Annie M.P. Smithson, the author of 21 romance novels between 1917 and 1946. Her attitudes towards women, religion and politics are explored, and the importance of autobiography in her fiction discussed.Cet article analyse divers aspects de l'oeuvre d'Annie M.P. Smithson, l'auteur de vingt et un romans 'romanesques' publiés entre 1917 et 1946. Il étudie son attitude concernant les femmes, la religion, la politique, ainsi que le rôle de l'autobiographie dans sa fiction.Walsh Oonagh. 'Her Irish Heritage' : Annie M.P Smithson and autobiography. In: Études irlandaises, n°23-1, 1998. pp. 27-42
Advances in understanding the Southern Ocean’s role in global climate: the ORCHESTRA and SOCCOM programs
No full textThe establishment of fucoid zonation on algal-dominated rocky shores: hypotheses derived from a simulation model
No full textA model was developed for the growth of intertidal algae with photosynthesis simulated both in air and in a tidal water column. Morphological data on dry mass per unit area and length-area relationships were used to separate the growth of different fucoid species. The relative growth rate of fronds at any height on the shore depended on a trade-off between net photosynthetic performance and tolerance to desiccation. 2. The simulated zonation patterns and growth rates were consistent with those observed previously for Fucus spp. and Pelvetia canaliculata. 3. The simulated growth of Ascophyllum nodosum was always slower than for the other species. This species did not form its characteristic distribution zones in simulations without including further processes in the model. However, Ascophyllum collected from the field could be separated into upper and lower shore morphologies which formed separate zones when they were simulated in competition with each other. 4. Several hypotheses were proposed concerning the relative locations and sharpness of interspecies boundaries on the shore. Zonation patterns were relatively insensitive to changes in most model parameters except the desiccation rate
Resolution of Unexpected IDEXX ELISA Positive Results for Antibodies Against Porcine Reproductive and Respiratory Syndrome Virus with IFA and A Blocking ELISA
No full textFerrin, N.H.; Torremorell, M.; Gramer, M.; Fang, Y.; Murtaugh, M.P.; Johnson, C.R.; Nelson, E.A.. (2002). Resolution of Unexpected IDEXX ELISA Positive Results for Antibodies Against Porcine Reproductive and Respiratory Syndrome Virus with IFA and A Blocking ELISA. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/160395
Beyond the predation halo: small scale gradients in barnacle populations affected by the relative refuge value of crevices
No full textHaloes of bare space around crevices used as refuges by predators are a feature of many rocky shores. The presence of small scale spatial gradients in the demographic structure of prey populations is hypothesized for the region adjoining predation haloes. It is also suggested that halo effects in prey populations will change in response to environmental constraints on predator foraging behaviour. These hypotheses were tested by examining gradients in barnacle population structure around crevices high and low on the shore. The probability of encountering a barnacle above the local median size always increased with distance from a crevice. Foraging at sites high on a shore is assumed to be more risky to individual whelks. Initial probabilities of recording a large barnacle near a crevice increased more rapidly over small spatial scales at sites high on the shore than at sites low on the shore. The implications of small scale gradients in prey populations are discussed with reference to the role of topographic complexity in mediating predator–prey dynamics
Il ruolo della linguistica in un'iniziativa di internazionalizzazione
No full textThe author deals with the role of linguistic sciences and language teaching in the internationalization project of an e-learning Specialization Course
Models of open populations with space-limited recruitment: extension of theory and application to the barnacle Chthamalus montagui
No full text1. Barnacles are a good model organism for the study of open populations with space-limited recruitment. These models are applicable to other species with open supply of new individuals and resource limitation. The inclusion of space in models leads to reductions in recruitment with increasing density, and thus predictions of population size and stability are possible.2. Despite the potential generality of a demographic theory for open space-limited populations, the models currently have a narrow empirical base. In this study, a model for an open population with space-limited recruitment was extended to include size-specific survival and promotions to any size class. The assumptions of this model were tested using data from a pan-European study of the barnacle Chthamalus montagui Southward. Two models were constructed: a 6-month model and a periodic annual model. Predicted equilibria and their stabilities were compared between shores.3. Tests of model assumptions supported the extension of the theory to include promotions to any size class. Mortality was found to be size-specific and density independent. Studied populations were open, with recruitment proportional to free space.4. The 6-month model showed a significant interaction between time and location for equilibrium free space. This may have been due to contrasts in the timing of structuring processes (i.e. creating and filling space) between Mediterranean and Atlantic systems. Integration of the 6-month models into a periodic annual model removed the differences in equilibrium-free space between locations.5. Model predictions show a remarkable similarity between shores at a European scale. Populations were persistent and all solutions were stable. This reflects the apparent absence of density-dependent mortality and a high adult survivorship in C montagui. As populations are intrinsically stable, observations of fluctuations in density are directly attributable to variations in the environmental forcing of recruitment or mortality
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