Weldability of steels for the manufacture of bicycle frames

Tato práce je zaměřena na ocelové materiály používané pro výrobu rámů jízdních kol. Slitiny jsou zde rozebrány nejen z hlediska svých mechanických vlastností, ale také svařitelnosti. Ocelové materiály jsou rozděleny do tří skupin podle předních výrobců rámových sad. U vybraných slitin s obchodním názvem je přiřazen ekvivalentní normovaný materiál volený podle chemického složení. Svařitelnost jednotlivých ocelí je rozdělena do kapitol podle mechanických vlastností a struktury. V práci je dále uvedeno, proč je upřednostněno svařování rámů metodou TIG a jaké jsou její hlavní výhody.This thesis is focused on steel materials used in bicycle frame manufacturing. The alloys are analysed based on their mechanical properties as well as their weldability. Steel materials are divided into three groups corresponding to the foremost frame manufacturers. Alloys with trade names are paired with equivalent normalized materials selected according to their chemical composition. The weldability of individual steels is addressed in several chapters sorted by materials’ mechanical properties and structure. The work further explains why TIG welding of frames is preferred and what the method’s main advantages are.

High performance paraglider aerodynamic optimization

Tato práce je zaměřena na aerodynamickou analýzu závodního paraglidingového vrchlíku. Odpory jednotlivých částí jsou rozděleny do kapitol. Cílem bylo vytvoření představy o velikosti podílu odporů jednotlivých komponent vůči kompletní sestavě. Nejprve byl zanalyzován 2D profil a následně celá konfigurace 3D vrchlíku. Po vyhodnocení byly zjištěny výkonové rezervy v profilu. Došlo tedy k optimalizaci jeho tvaru. Po optimalizaci jednotlivých prvků došlo opět k CFD výpočtu. Na závěr byly zhodnoceny změny geometrie.This thesis is focused on the aerodynamic analysis of the competition paraglider wing. Drags of the particular wing parts are divided into chapters. The aim was to get a grasp of sizes of the individual components drags in relation to the entire assembly. In the first instance, a 2D profile and then the entire configuration of the 3D wing was analyzed. After the evaluation, some power reserves were detected in an airfoil and so the airfoil shape was optimized. After the optimization of the individual components, the CFD calculation was used again. At the end, geometry changes were evaluated.

Strengthening Community Schools Through University Partnerships

Given the mounting call for academic achievement gains in America’s public schools— particularly urban schools labeled “failing”—the need for community engagement to tackle a host of underlying social challenges warrants the resources of the nation’s colleges and universities (Harkavy & Hartley, 2009). Because colleges and universities are often underutilized anchors of resources in communities, coordinated alignment of K-12 and higher education goals can create a seamless pipeline of educational attainment for communities challenged to produce high academic achievement. Higher education’s engagement with community schools further helps to address the whole child and their families in K-12 education by expanding the opportunities for the students and community to access necessary support services. Drawing upon experiences of Indiana University Purdue University Indianapolis (IUPUI) and collaboration with its adjacent neighborhoods, this article illustrates the transformative and relevant impact of university and community engagement, as well as new pedagogical approaches to teaching, learning, and training. This article reflects upon the experiences of IUPUI and nearby George Washington Community High School as it can uniquely serve as a roadmap for other school community/university partnerships that are interested in embarking upon a similar education reform path

A game-theoretic model of interspecific brood parasitism with sequential decisions

The interaction between hosts and parasites in bird populations has been studied extensively. This paper uses game-theoretic methods to model this interaction. This has been done in previous papers but has not been studied taking into account the detailed sequential nature of this game. We introduce a model allowing the host and parasite to make a number of decisions which will depend on various natural factors. The sequence of events begins with the host forming a nest and laying a number of eggs, followed by the possibility that a parasite bird will arrive at the nest; if it does it can choose to destroy some of the host eggs and lay one of its own. A sequence of events follows, which is broken down into two key stages; firstly the interaction between the host and the parasite adult, and secondly that between the host and the parasite chick. The final decision involves the host choosing whether to raise or abandon the chicks that are in the nest. There are certain natural parameters and probabilities which are central to these various decisions; in particular the host is generally uncertain whether parasitism has taken place, but can assess the likelihood of parasitism based upon certain cues (e.g. how many eggs remain in its nest). We then use this methodology to model two real-world interactions, that of the Reed Warbler with the Common Cuckoo and also the Yellow Warbler with the Brown-headed Cowbird. These parasites have different methods in the way they parasitize the nests of their hosts, and the hosts can in turn have different reactions to these parasites. Our model predictions generally match the real results well, and the model also makes predictions of the effect of changes in various key parameters on the type of parasitic interactions that should occur

Oligotyping : differentiating between closely related microbial taxa using 16S rRNA gene data

© The Authors. Methods in Ecology and Evolution © 2013 British Ecological Society.. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Methods in Ecology and Evolution 4 (2013): 1111–1119, doi:10.1111/2041-210X.12114.Bacteria comprise the most diverse domain of life on Earth, where they occupy nearly every possible ecological niche and play key roles in biological and chemical processes. Studying the composition and ecology of bacterial ecosystems and understanding their function are of prime importance. High-throughput sequencing technologies enable nearly comprehensive descriptions of bacterial diversity through 16S ribosomal RNA gene amplicons. Analyses of these communities generally rely upon taxonomic assignments through reference data bases or clustering approaches using de facto sequence similarity thresholds to identify operational taxonomic units. However, these methods often fail to resolve ecologically meaningful differences between closely related organisms in complex microbial data sets. In this paper, we describe oligotyping, a novel supervised computational method that allows researchers to investigate the diversity of closely related but distinct bacterial organisms in final operational taxonomic units identified in environmental data sets through 16S ribosomal RNA gene data by the canonical approaches. Our analysis of two data sets from two different environments demonstrates the capacity of oligotyping at discriminating distinct microbial populations of ecological importance. Oligotyping can resolve the distribution of closely related organisms across environments and unveil previously overlooked ecological patterns for microbial communities. The URL http://oligotyping.org offers an open-source software pipeline for oligotyping.This work was supported by the National Institutes of Health [1UH2DK083993 to M.L.S.] and the Alfred P. Sloan Foundation

Pennsylvania Folklife Vol. 26, Folk Festival Supplement

• Bonnets, Bonnets, Bonnets • Theorem Painting on Velvet • Spinning, Weaving and Lace Making • Mennonites: A Peaceful People • Special Police Force Directs Traffic • Candle Dipping and Molding • Festival Focus • Folk Festival Programs • The Old One-Room School • The Art of Making Brooms • Koom Rei, Huck Dich un Essa (Come In, Sit Down and Eat) • Old Fashioned Apple Butter Making • Fraktur: An Enduring Art Form • Covered Bridges: Folk Festival Questionnairehttps://digitalcommons.ursinus.edu/pafolklifemag/1074/thumbnail.jp