Measurement of Altitude in Blind Flying

In this note, instruments for measuring altitude and rate of change of altitude in blind flying and landing of aircraft and their performance are discussed. Of those indicating the altitude above ground level, the sonic altimeter is the most promising. Its present bulk, intermittent operation, and more or less unsatisfactory means of indication are serious drawbacks to its use. The sensitive type aneroid altimeter is also discussed and errors in flying at a pressure level and in landing are discussed in detail

Equilibrium of a Brownian particle with coordinate dependent diffusivity and damping: Generalized Boltzmann distribution

Fick's law for coordinate dependent diffusivity is derived. Corresponding diffusion current in the presence of coordinate dependent diffusivity is consistent with the form as given by Kramers-Moyal expansion. We have obtained the equilibrium solution of the corresponding Smoluchowski equation. The equilibrium distribution is a generalization of the Boltzmann distribution. This generalized Boltzmann distribution involves an effective potential which is a function of coordinate dependent diffusivity. We discuss various implications of the existence of this generalized Boltzmann distribution for equilibrium of systems with coordinate dependent diffusivity and damping.Comment: 11 pages, 1 figur

Development of a computerised workshop management program

A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Soience in Engineering. Johannesburg 1991It is generally accepted that if a company's stock control and shop floor control systems are inadequate or they operate inefficiently, then both productivity and profit potential within the company will inevitably be low. Such a company was investigated and the results presented in this report showed that the company's profile gives cause for concern. A study of the company's operating procedures showed that it Was operated in a static, paper driven environment which resulted in both an inadequate stock control system and a chaotic shop floor control system. This projeot report looks at the feasibility of introducing a menu driven data base to operate an order point inventory system within an independent demand environment, as well as monitoring shop flOOr activity. The introduction of the data base would result in a dynamic, realtime shop floor control system. By using the data base the stock levels could be reduced by as much as 77 percent from present levels and the store could be run on modern stock control methods without the store managers having any knowledge of stock control. As a result of introducing the stock control system it was anticipated that the time to train staff would also bf reduced substantially, the company could now account for every expense incurred and the opportunities for pilferage would be greatly reduced. The computer package was written in such a manner that computer recommendations could be overwritten by system users, thus the human element was retained and stores personnel would not be given the feeling of being redundant. The introduction of this data base would allow the company to respond to challenges an problems in a dynamic and accurate way

Reliability improvement of electronic circuits based on physical failure mechanisms in components

Traditionally the position of reliability analysis in the design and production process of electronic circuits is a position of reliability verification. A completed design is checked on reliability aspects and either rejected or accepted for production. This paper describes a method to model physical failure mechanisms within components in such a way that they can be used for reliability optimization, not after, but during the early phase of the design process. Furthermore a prototype of a CAD software tool is described, which can highlight components likely to fail and automatically adjust circuit parameters to improve product reliability

Abfälle und Kuhfladen - Leben im neolithischen Dorf : zu Forschungsergebnissen, Methoden und zukünftigen Forschungsstrategien archäobotanischer Untersuchungen von neolithischen Seeufer- und Moorsiedlungen

In den letzten 25 Jahren wurden durch archäobotanische (und archäozoologische) Untersuchungen an Seeufer- und Moorsiedlungen im Umkreis der Alpen zahlreiche quantifizierbare Informationen über das tägliche Leben der Menschen im Neolithikum erarbeitet. Es ist mindestens für verschiedene Zeiträume und Regionen zur Genüge bekannt, was angebaut und gesammelt wurde. Doch was wissen wir darüber hinaus? Von Interesse für die archäologische Forschung sind vor allem Kenntnisse zur inneren Organisation von Siedlungen, d.h. wo Abfälle hingeworfen wurden, ob und wann sich Tiere in der Siedlung aufhielten und ob die Bewohner und Bewohnerinnen einzelner Gebäude sich unterschiedlich ernährten. Erst, wenn solche Informationen über „intra-site-patterns“ in einer Siedlung vorliegen, können Differenzen zwischen Siedlungsplätzen herausgearbeitet werden. Im Beitrag wird dargelegt, dass wir darüber nach wie vor sehr wenig wissen, d.h. es gibt trotz zahlreicher Rettungsgrabungen viel zu wenige repräsentativ untersuchte Siedlungsplätze. Ausserdem sind die Kenntnisse über landwirtschaftliche Tätigkeiten in einzelnen Regionen nach wie vor sehr lückenhaft. Von fast der die Hälfte der 86 seit den 60er Jahren des letzten Jahrhunderts untersuchten Siedlungsplätze gibt es nur statistisch nicht verwertbare Daten. Es besteht also weiterhin viel Forschungsbedarf, wollen wir eines Tages Aussagen über „spezialisierte“ Siedlungen machen oder mehr Erkenntnisse zu Aktivitäten von BewohnerInnen einzelner Häuser gewinnen. Im Hinblick darauf wird dargelegt, wie Siedlungsplätze beprobt werden müssen, um sich möglichst alle Optionen für eine Auswertung offen zu halten. Wichtig wäre es für die Zukunft ausserdem, beim im Sieben der Proben und bei der Quantifizierung der Reste ein standardisiertes Vorgehen anzuwenden

Simulation, a tool for designing-in reliability

This paper describes a new method for the analysis and optimization of reliability as an integrated part of the design process of electronic circuits. It bases itself on the analysis of the susceptibility of failure mechanisms in components as a function of the combinations of external stress factors (stressor-sets). The paper describes the backgrounds of stressor-susceptibility analysis, the need for this analysis and the way this method is used for high-level design and optimization of electronic circuits

El negocio transatlántico de la cocaína: opciones europeas ante las nuevas rutas del narcotráfico

Este Documento de Trabajo busca analizar estas medidas de intervención, recientemente reafirmadas por la CDE. Partiendo del precio de la droga, se analiza el problema del narcotráfico y se evalúa la eficiencia de las políticas de control de oferta. Sin duda, cualquier política de control de drogas no puede estar fundada únicamente en el control de oferta, sino también en medidas de reducción de la demanda. Sin embargo, el interés de este trabajo se centra en la revisión de los instrumentos europeos de política exterior sobre el control de la oferta y deja de lado medidas de política interior de reducción de la demanda, cuya eficacia es generalmente reconocida en la mayoría de los países de la UE

T Helper1/T Helper2 Cells and Resistance/Susceptibility to Leishmania Infection: Is This Paradigm Still Relevant?

Work in large part on Leishmania major in the 1980s identified two distinct apparently counter-regulatory CD4+ T cell populations, T helper (h)1 and Th2, that controlled resistance/susceptibility to infection respectively. However, the generation of IL-4−/− mice in the 1990s questioned the paramount role of this Th2 archetypal cytokine in the non-healing response to Leishmania infection. The more recent characterization of CD4+ T cell regulatory populations and further effector CD4+ T helper populations, Th17, Th9, and T follicular (f)h cells as well as the acknowledged plasticity in T helper cell function has further added to the complexity of host pathogen interactions. These interactions are complicated by the multiplicity of cells that respond to CD4+ T cell subset signatory cytokines, as well as the diversity of Leishmania species that are often subject to significantly different immune-regulatory controls. In this article we review current knowledge with regard to the role of CD4+ T cells and their products during Leishmania infection. In particular we update on our studies using conditional IL-4Rα gene-deficient mice that have allowed dissection of the cell interplay dictating the disease outcomes of the major Leishmania species infecting humans