Optimización de tensiones de marcos de bicicleta

El interés hacia la optimización del diseño de los productos siempre ha sido una constante dentro de la industria, y esta ha sido la motivación para la realización de este Trabajo Fin de Grado. El propósito del mismo consiste en modelar y optimizar la geometría de cuatro modelos diferentes de cuadros de bicicleta disponibles en el mercado. El proyecto se divide en dos segmentos: diseño y modelado de los marcos y, análisis y optimización de las tensiones soportadas por estos. El primero consiste en la creación de los cuadros de las bicicletas en CATIA V5® a partir de los datos que las diferentes marcas dan de sus geometrías. Estos cuadros de bicicleta deben tener sus variables parametrizadas, para poder cambiarlas en un rango determinado. El siguiente paso es realizar el análisis de tensiones bajo una fuerza externa utilizando también el programa CATIA V5®, y combinándolo con el programa de optimización multiobjetivo Mode FRONTIER 2017®, averiguar cuál es el diseño del cuadro de la bicicleta con la mejor relación resistencia-peso

Hepatocyte Growth Factor Activator Inhibitor-1 Is Induced by Bone Morphogenetic Proteins and Regulates Proliferation and Cell Fate of Neural Progenitor Cells

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Static Structural Analysis of Hydrofoil Struts

I kursen TMMT06, Maskinteknik – projektkurs, genomförs ett obligatoriskt projekt. Projektet utförs som kandidatexamensjobb i studentpar och delas i detta fall av tre kandidatpar. Det projekt som detta kandidaterbete ingår i behandlar dimensionering av bärplan och deras prestanda. Kandidatarbetet är riktat mot en hållfasthetsanalys av bärplansstag för statiska fall under inverkan av genererad lyftkraft och strömningsmotstånd. Syftet med kandidatarbetet är att skapa ett konstruktionsunderlag till det projekt som delas av kandidatparen. Målet med kandidatarbetet är att genom en hållfasthetsanalys ta fram vägledande underlag för dimensionering av bärplansstagens monteringsvinklar och storlek. Med hjälp av vedertagna ekvationer för lyftkraft och strömningsmotstånd och bärplansdata analyseras de krafter och spänningar som är dimensionerande vid utformning av stagets tvärsnittsprofil och monteringsvinklar. Två strömlinjeformade homogena stag med tjockleken 15 mm och bredden 100 mm monterat på ett bärplan med profilen Eppler 818 studeras i ett statiskt fall utan dimensionering för oväntade händelser såsom kollision. För hastigheter som är rimliga för en båt kan det konstateras att det aldrig uppstår fara för knäckning. Spänningen för dessa hastigheter blir inte heller tillräckligt hög för att orsaka plastisk deformation, men säkerhetsfaktorn blir relativt liten. Risken för knäckning ökar aldrig oavsett val av monteringsvinklar och upphör helt för angreppsvinklar som är mindre än −4°. Risk för plastisk deformation ökar däremot markant om konstruktionen ges monteringsvinklar som inte är vinkelräta mot horisontalplanet. För större stagprofiler kan konstruktionen ges något större vinklar, men att vinkla stagen bör om möjligt undvikas. Analysen visar också att båten inte bör stampa mer än 6° vid höga hastigheter för att undvika för stora spänningar. De största dimensionerande spänningarna i staget uppträder i infästningspunkterna mellan skrov respektive bärplan. För att i övrigt minimera stagtvärsnittets tjocklek, och därmed minska strömningsmotståndet kan staget lokalt göras tjockare i dessa punkter. Analysen visar även att endast en liten ökning av stagtvärsnittets dimensioner får ett stort positivt genomslag i säkerhet mot knäckning och deformation. Fler bärplansprofiler än Eppler 818 studeras inte, men resultaten ger en god vägledning till konstruktion av bärplansstag med avseende på hållfasthet.In the course TMMT06, Mechanical engineering – project course, a mandatory project is carried out in a group, while a bachelor’s degree work is, in unison, carried out in pairs. The project, which in this case is shared by three pairs, aim to investigate the dimensioning of hydrofoils and their performance. This document is part of one of those bachelor’s degree works, and is focused on a static structural analysis of hydrofoil support struts under the influence of lift and drag forces. The goal with this work is to create a construction foundation to be used in the shared project. The aim of the work is to find guidelines for the selection of strut and hydrofoil assembly angles, as well as strut dimensions, depending on the size and shape of the hydrofoil. With the use of generally established equations for lift and drag forces, and data for hydrofoils the forces and stresses crucial to the dimensioning of the strut cross-section and assembly angles are analyzed. Two streamlined struts, thickness 15 mm and width 100 mm, with the hydrofoil section design Eppler 818 mounted, are studied in a static structural case without dimensioning for unexpected events, such as collisions. Within the span of velocities that are probable for a boat it was found that there never occurs any danger of buckling. Within the same span, plastic deformation does not occur either, although the stress is high enough that the safety margin is relatively small. The danger of buckling does not increase as the assembly angles are changed from a perpendicular position, and buckling ceases to be a factor for angles of attack lower than −4°. The stresses and the risk for plastic deformation, however, can increase as the assembly angles deviate from perpendicularity. By making the struts bigger, the construction will be able to use more demanding assembly angles, but to have anything but perpendicular struts is to be avoided. The analysis also shows that the boat should not be allowed to pitch more than 6° at high speeds to avoid large stresses in the struts. The largest dimensioning stress in a strut acts at the connection point with the hull or with the hydrofoil. In order to minimize the total thickness of the strut, and thus lowering the drag, it can be made thicker at the connection points while keeping it thin otherwise. The analysis also shows that an increase in strut cross-section area will give large positive outcomes in terms of safety margins against buckling and deformation. Eppler 818 was the only hydrofoil studied during the analysis, but the results provide good guidelines for construction of support struts in regards of strength

Is Design Automation a Feasible Tool for Improving Efficiency in Production Planning and Manufacturing Processes?

The production planning is a repetitive process that demands engineering hours and expertise. Many parameters must be considered, and inefficiencies lead to increased lead times. The hypothesis is that valuable time within the manufacturing stages can be saved through improved engineering tools. This article will explore to possibilities to increase the utilization of digital tools to support the engineers in their production planning activities, and to improve the efficiency of manufacturing processes. Through study visits and interviews at a product owning company with manufacturing in-house, proposals for areas that could be improved with design automation will be presented

Effects of HAI-1 and HAI-2 overexpression and downregulation on cell proliferation in NPCs.

<p>NPCs were isolated from developing E17-old striatum and were transfected as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0056117#s4" target="_blank">Methods</a> using overexrepressing constructs or silencing RNA (siRNA) as indicated. (<b>A</b>) Left, Schematic view of human full-length and transmembrane-lacking (dTM) constructs of HAI-1 and HAI-2. 8 µg of expression plasmids for these constructs were transfected into NPCs as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0056117#s4" target="_blank">Methods</a>. Control cells were transfected with EGFP plasmids. Right, Immunoblots of transfected cells detected using anti-HAI-1 and anti-HAI-2 antibodies detecting human HAI-1 at 66 kDa, and human HAI-2 at 34 kDa and 28 kDa, respectively. N, aminoterminus; KD, Kunitz domain; LDLR, LDL receptor-like domain; TM, transmembrane domain; C, carboxyterminus. (<b>B</b>) The number of Ki67-positive of all cells was determined by immunocytochemistry. Expression of HAI-1 and HAI-2 for 6 days reduced the number of dividing cells compared with controls (mock). Values are means ± SEM, n = 3. **p<0.01 for HAI-1 constructs vs. control, and *p<0.05 for HAI-2 constructs vs. control. (<b>C</b>) Immunoblot of the cell cycle regulator, CyclinD1. ß-actin was used as a control. Quantification below shows a decrease in CyclinD1 after HAI-1 and HAI-2 expression. Values are means ± SEM, n = 4. ***p<0.001 for HAI-1 vs. control, and **p<0.01 for HAI-2 vs. control. (<b>D</b>) Downregulation of HAI-1 by siRNA increased the number of dividing cells. Control cells received scrambled siRNA. After 3 days with siRNA the number of BrdU-positive cells was determined by immunostaining. Values are means ± SEM, n = 4. *p<0.05 for HAI-1 siRNA vs. control. HAI-1 levels are shown to the right. (<b>E</b>) Cell culture supernatant from hybridoma cells producing monoclonal anti-HAI-1 antibodies (MG2, see Hallikas et al., 2006) was diluted 1∶50 and added to the cultures for 3 days. Note an increase in the number of dividing NPCs. Values are means ± SEM, n = 3. *p<0.05 for MG2 vs. control. (<b>F</b>) Downregulation of HAI-2 by siRNA increased the number of BrdU-positive dividing cells after 3 days. Control cells received scrambled siRNA. Values are means ± SEM, n = 3. *p<0.05 for HAI-2 siRNA vs. control. HAI-2 mRNA levels are shown to the right. (<b>G</b>) Immunoblot of Erk1/2. The phosphorylation of Erk1/2 was reduced by HAI-1 overexpression. Total Erk1/2 was not changed. ß-actin was used as a control. Quantification below. Values are means ± SEM, n = 3. *p<0.05 for HAI-1 vs. control.</p

Effects of BMPs and HAI-1 and HAI-2 on cell differentiation.

<p>(<b>A</b>) NPCs were isolated from developing striatum of E17 old rats and stimulated with 25 ng/ml BMP-4 for 4 days followed by incubation without EGF to induce cell differentiation (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0056117#s4" target="_blank">Methods</a>). The relative numbers of neurons (ß-tubulin), astrocytes (GFAP) and oligodendroglial (CNPase) cells were identified using specific antibodies. Note an increase in number of GFAP-positive cells by BMP-4. Values are means ± SEM, n = 4. *p<0.05 for BMP-4 vs. C. (<b>B</b>) NPCs were transfected with 5 µg of HAI-1 or HAI-2 expression plasmids and cell differentiation was induced for 5 days. The number of specific cell types was determined by immunostaining. Note an increase in number of GFAP-positive cells by HAI-1. Values are means ± SEM, n = 4. *p<0.05 for HAI-1 vs. control. (<b>C</b>) NPCs were transfected with HAI-1 siRNA and stimulated with BMP-2 for 24 h and cell differentiation was induced for 5 days. BMP-2 increased the number of GFAP-positive cells and this effect was inhibited by the downregulation of HAI-1. Values are means ± SEM, n = 3. **p<0.01 for BMP-2+HAI-1 siRNA vs. BMP-2 alone.</p

Expression of HAI-1 in developing E17-old rat brain promotes glial cell fate.

<p>E17 old mice embryos were electroporated as described above and the brains processed at postnatal day 1 (P1). (<b>A</b>) P1-old sections were immunostained with anti-GFAP antibodies (red). The number of double stained cells in the marginal zone was counted and expressed as a percentage of total GFP-positive cells (green). The merged pictures show coexpression of GFAP and GFP. Upper panel, injection of GFP control plasmid. Lower panel, HAI-1 expression plasmids. Scale bar, 100 µm. MZ, marginal zone; CP, cortical plate; IZ, intermediate zone; SVZ, subventricular zone; VZ, ventricular zone. (<b>B</b>) Higher magnification. Scale bar, 25 µm. Quantification to the right. Values are means ± SEM. n = 3. *p<0.05 for HAI-1 vs. GFP. (<b>C</b>) Higher magnification shows colozalization of HAI-1 and GFP stained cells in the MZ. Scale bar, 25 µm.</p