Characterisation of HTSC ceramics from their resistive transition

The resistivity vs. temperature relation in bulk ceramic HTSC under self-field conditions as well as in weak external magnetic fields is modelled by local Lorentz force induced fluxon motion with temperature dependent pinning. A pinning force density and two viscous drag coefficients in intergrain and intragrain regions, respectively, can be used as characteristic parameters describing the temperature, current, and external field dependences of the sample resistance.Comment: 12 pages, LaTeX2e, 6 figures (epsfig), to be published in Supercond. Sci. and Techno

Cathodoluminescence and TEM investigations of structural and optical properties of AlGaN on epitaxial laterally overgrown AlN/sapphire templates

Surface steps as high as 15 nm on up to 10 μm thick AlN layers grown on patterned AlN/sapphire templates play a major role for the structural and optical properties of AlxGa1−xN layers with x ≥ 0.5 grown subsequently by metalorganic vapour phase epitaxy. The higher the Ga content in these layers is, the stronger is the influence of the surface morphology on their properties. For x = 0.5 not only periodic inhomogeneities in the Al content due to growth of Ga-rich facets are observed by cathodoluminescence, but these facets give rise to additional dislocation formation as discovered by annular dark-field scanning transmission electron microscopy. For AlxGa1−xN layers with x = 0.8 the difference in Al content between facets and surrounding material is much smaller. Therefore, the threading dislocation density (TDD) is only defined by the TDD in the underlying epitaxially laterally overgrown (ELO) AlN layer. This way high quality Al0.8Ga0.2N with a thickness up to 1.5 μm and a TDD ≤ 5x108 cm−2 was obtained

The development of a supply chain operations reference model for the telecommunications industry

Thesis (M.Ing) -- University of Stellenbosch, 1999.ENGLISH SUMMARY: The goal of this thesis is to develop a model that will describe the Supply Chain within a telecommunications company. The telecommunications industry within South Africa is faced with a number of changes, the most important of which is the introduction of competition into the market. Telkom, South Africa's telecommunications company, has started with a project of rapid expansion of its network in response to these potential entrants. Skills are being sought that will give the company the edge over its competitors. One of these skills is Supply Chain Management. The telecommunications company is traditionally seen as a service organization. Despite this fact, it has been shown that the company does have manufacturing dimensions. These manufacturing dimensions may be improved by considering the skills used within a traditional manufacturing firm, and applying them to the telecommunications company. One way of introducing these skills is by developing a model that will describe the telecommunications company. This has been done within this thesis. It will be shown that the model is capable of describing the company. It is shown that the use of Supply Chain Management skills and the use of the model could give a telecommunications company the edge over its competitors.AFRIKAANSE OPSOMMING: Die doel van hierdie tesis is die daarstel van 'n model wat die toevoerketting van 'n telekommunikasie maatskappy beskryf. Die telekommunikasie industrie binne Suid-Afrika is besig om groot veranderinge te ondergaan, veral met die bekendstelling van kompetisie tot die industrie. Hierdie bekendstelling van kompetisie het tot 'n skielike groei in die infrastruktuur gelei, so os Suid-Afrika se telekommunikasie maatskappy, Telkom, voorberei vir hierdie kompetisie. Vaardighede word gesoek wat maatskappye die voorsprong sal gee op hul mededingers. Een so 'n voorsprong is die bestuur van die toevoerketting. Alhoewel die telekommunikasie maatskappy tradisioneel gesien word as 'n diensverskaffer, is daar gevind dat dit ook vervaardigings elemente bevat. Hierdie vervaardigings elemente kan heel moontlik beter bestuur word deur te kyk na die vaardighede van vervaardigings ondemernings, en dan hierdie vaardighede toe te pas op die telekommunikasie maatskappy. Een manier om hierdie vaardighede toe te pas, is deur 'n model te ontwikkel wat die telekommunikasie industrie beskryf. Daar is gewys dat die nuwe model wat ontwikkel is weI die industrie kan beskryf. Die tesis wys verder ook dat die tegnieke verbonde aan die bestuur van die toevoerketting sowel as die gebruik van die model, wel 'n telekommunikasie maatskappy kan onderskei van sy mededingers.Maste

Semantic Integration of Cervical Cancer Data Repositories to Facilitate Multicenter Association Studies: The ASSIST Approach

The current work addresses the unifi cation of Electronic Health Records related to cervical cancer into a single medical knowledge source, in the context of the EU-funded ASSIST research project. The project aims to facilitate the research for cervical precancer and cancer through a system that virtually unifi es multiple patient record repositories, physically located in different medical centers/hospitals, thus, increasing fl exibility by allowing the formation of study groups “on demand” and by recycling patient records in new studies. To this end, ASSIST uses semantic technologies to translate all medical entities (such as patient examination results, history, habits, genetic profi le) and represent them in a common form, encoded in the ASSIST Cervical Cancer Ontology. The current paper presents the knowledge elicitation approach followed, towards the defi nition and representation of the disease’s medical concepts and rules that constitute the basis for the ASSIST Cervical Cancer Ontology. The proposed approach constitutes a paradigm for semantic integration of heterogeneous clinical data that may be applicable to other biomedical application domains

Теплогидравлический расчёт ТВС ИРТ-3М в реакторе ИРТ-Т с различными поверхностями теплообмена

The master’s thesis has attempted to model thermal-hydraulic behavior of the fuel assembly of IRT-3M type of IRT-T reactor with various heat-conductivity surfaces.В магистерской диссертации приведено теплогидравлическое моделирование ТВС типа ИРТ-3М реактора ИРТ-Т с различными поверхностями теплообмена

Origin of a-plane (Al,Ga)N formation on patterned c-plane AIN/sapphire templates

a-plane (Al,Ga)N layers can be grown on patterned c-plane AlN/sapphire templates with a ridge direction along [1bar 100]Al2O3. Scanning nanobeam diffraction reveals that the formation of a-plane layers can be explained by nucleation of c-plane (Al,Ga)N with [11bar 20](Al,Ga)N[0001]Al2O3 at the ridge sidewalls. Faster growth of the top (11bar 20)(Al,Ga)N facet in the vertical direction leads to the overgrowth of c-plane (Al,Ga)N nucleated on the horizontal ridge and trench surfaces. Phase separation into binary GaN and AlN takes place during the first growth stages. However, this fades out and does not influence the composition of the final thick a-plane (Al,Ga)N layer

Lipoperoxidation levels in rainbow trout and broiler chickens after levofloxacin administration

La levofloxacina es un antimicrobiano del grupo de las fluoroquinolonas utilizada en medicina humana y con potencial aplicación en animales de producción, si los estudios toxicológicos y farmacológicos lo avalan. Si bien trabajos previos han demostrado que otras fluoroquinolonas y/o sus metabolitos producen peroxidación de lípidos en los tejidos animales, las comunicaciones sobre evaluaciones toxicológicas de levofloxacina son escasas. En el presente trabajo se plantea evaluar la posible oxidación de lípidos en tejidos de pollos parrilleros y truchas (Oncorhynchus mykiss), después de la administración de levofloxacina utilizando la técnica de sustancias reactivas al ácido tiobarbitúrico (TBARs). Los valores de nmol de TBARs/g de tejido mostraron diferencias estadísticamente significativas en: músculo de trucha después de una única administración de 10mg/kg de levofloxacina 50,2±3,2 vs control 17,1±3,8 (p<0,05) a las 72 h; en pollo, después de una única administración de 5mg/kg de levofloxacina, los valores fueron, en músculo a las 2 h, 6,2±1,2 vs control 3,7±1,3 (p<0,05) y en hígado a la hora, 6,9±0,2 vs control 0,9±0,1 (p<0,05). Esta información, que sugiere inducción de un efecto oxidativo en tejidos, debe ser profundizada en futuras investigaciones.Levofloxacin is a fluoroquinolone antimicrobial used in human medicine and with a potential application in food-producing animals, if the toxicological and pharmacological studies support this. Previous studies have shown that other fluoroquinolones and/or its metabolites produce lipid peroxidation in animal tissues but toxicological evaluation of levofloxacin communications are scarce. This work argues evaluate the possible lipid oxidation in broiler chickens and trout (Oncorhynchus mykiss) tissues, after levofloxacin administration, using the thiobarbituric acid reactive substances technique (TBARs). The values, TBARs/g of tissue, showed statistically significant differences in: trout muscle after a10mg/kg single administration of levofloxacin 50.2±3.2 vs control 17.1±3.8 (p<0.05) at 72 h; in chicken after a single 5mg/kg levofloxacin administration, the values were in muscle at 2 h, 6.2±1.2 vs control 3.7±1.3 (p<0.05) and in liver at 1h, 6.9±0.2 vs control 0.9±0.1 (p<0.05). This information which suggests oxidative effect induction in tissues should be deepened in future research.Fil: Weyers, A.. Universidad Nacional de Rio Cuarto. Facultad de Agronomia y Veterinaria. Departamento de Salud Publica; ArgentinaFil: Ugnia, L. Universidad Nacional de Rio Cuarto. Facultad de Agronomia y Veterinaria. Departamento de Salud Publica; ArgentinaFil: Garcia Ovando, Hugo. Universidad Nacional de Río Cuarto. Facultad de Agronomía y Veterinaria. Departamento de Clínica Animal; ArgentinaFil: Mañas, Fernando Javier. Universidad Nacional de Rio Cuarto. Facultad de Agronomia y Veterinaria. Departamento de Salud Publica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gorla, Nora Bibiana Maria. Universidad "Juan Agustín Maza". Facultad de Ciencias Veterinarias y Ambientales; Argentina. Universidad Nacional de Rio Cuarto. Facultad de Agronomia y Veterinaria. Departamento de Salud Publica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin