980 resultados para FREE-SPACE
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The impending introduction of lead-free solder in the manufacture of electrical and electronic products has presented the electronics industry with many challenges. European manufacturers must transfer from a tin-lead process to a lead-free process by July 2006 as a result of the publication of two directives from the European Parliament. Tin-lead solders have been used for mechanical and electrical connections on printed circuit boards for over fifty years and considerable process knowledge has been accumulated. Extensive literature reviews were conducted on the topic and as a result it was found there are many implications to be considered with the introduction of lead-free solder. One particular question that requires answering is; can lead-free solder be used in existing manufacturing processes? The purpose of this research is to conduct a comparative study of a tin-lead solder and a lead-free solder in two key surface mount technology (SMT) processes. The two SMT processes in question were the stencil printing process and the reflow soldering process. Unreplicated fractional factorial experimental designs were used to carry out the studies. The quality of paste deposition in terms of height and volume were the characteristics of interest in the stencil printing process. The quality of solder joints produced in the reflow soldering experiment was assessed using x-ray and cross sectional analysis. This provided qualitative data that was then uniquely scored and weighted using a method developed during the research. Nested experimental design techniques were then used to analyse the resulting quantitative data. Predictive models were developed that allowed for the optimisation of both processes. Results from both experiments show that solder joints of comparable quality to those produced using tin-lead solder can be produced using lead-free solder in current SMT processes.
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Today, doctors can be publishers – computer technology and the internet make it possible, and book projects are tempting in terms of money. A doctor who publishes his own textbooks can earn many times what he would be paid in royalties by a publishing house. More important than this, however, is the fact that a doctor who writes and publishes wants his texts to be read by as many colleagues, students and patients as possible. The best way to achieve this is through free parallel publication of these texts on the internet
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Free Tube Jet - Impingemenet - Heat Transfer - Arrary - Infrared Techuique - Hole Channels - Heat Transfer Uniformaty
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Magdeburg, Univ., Fak. für Naturwiss., Diss., 2010
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Otto-von-Guericke-Universität Magdeburg, Fakultät für Naturwissenschaften, Univ., Dissertation, 2015
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Die Bachelorarbeit besteht aus der Übersetzung des NASA-Berichtes „Pioneering Space: NASA’s Next Steps on the Path to Mars“ vom Englischen ins Deutsche und einer Textanalyse nach dem Analysemodell von Christiane Nord. Dieser Analyseansatz wird grob nach den sog. textexternen und textinternen Faktoren aufgeteilt. Zu den Besonderheiten und Herausforderungen der Übersetzung werden u.a. das hohe fachsprachliche Textniveau sowie diverse Abkürzungen und Abteilungsnamen innerhalb der NASA, die im Bericht auftauchen, gehören. Da darüber hinaus die Berichte und Kommunikation in der Weltraumszene hauptsächlich in englischer Sprache erfolgt, muss ein Kompromiss gefunden werden, um die Wörter so im Text einzubringen, dass der Textfluss nicht übertrieben gestört wird.
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Descriptive and comparative studies on tongue of nineteen Molossidae, one Mystacinidae, and four Vespertilionidae bats species were carried out. Analysis was restricted to the external morphology, covering general shape of the tongue and its papillae. Types of papillae and their distribution presented considerable intergeneric variation, considering the strictly insectivorous feeding habits of these bats. Distribution of the data of tongue morphology is analyzed and compared with the phylogenetic schemes proposed previously and comments about evolutionary relationships among taxa were done.
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This work describes the spatial-temporal variation of the relative abundance and size of Limnoperna fortunei (Dunker, 1857) collected in São Gonçalo Channel through bottom trawl with a 0.5 cm mesh, at depths between 3 and 6 m. The estimative of mean relative abundance (CPUE) ranged from 2,425.3 individuals per drag (ind./drag) in the spring to 21,715.0 ind./drag in the fall, with an average of 9,515.3 ind./drag throughout the year. The estimated mean density of L. fortunei for the deep region of São Gonçalo Channel ranged from 1.2 to 10.3 ind./m², and it was recorded a maximum density of 84.9 ind./m² in the fall of 2008. The method of sampling using bottom trawl enabled the capture of L. fortunei under the soft muddy bottom of the channel, in different sizes ranging from 0.4 to 3.2 cm. This shows that the structure of the L. fortunei adult population under the bottom of the São Gonçalo Channel is composed mostly of small individuals (<1.4 cm), which represent up to 74% of the population collected.
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Let F be a free group of rank at least three. We show that some retracts of F previously studied by Martino-Ventura are not equal to the fixed subgroup of any group of automorphisms of F. This shows that, in F, there exist subgroups that are equal to the fixed subgroup of some set of endomorphisms but are not equal to the fixed subgroup of any set of automorphisms. Moreover, we determine the Galois monoids of these retracts, where, by the Galois monoid of a subgroup H of F, we mean the monoid consisting of all endomorphisms of F that fix H.