• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 4
  • 4
  • 3
  • 2
  • 1
  • Tagged with
  • 15
  • 15
  • 6
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Utveckling av CBC Strap Cutter : Genom att möjliggöra en viss materialseparation tillsammans med en förenklad tömningsprocess

Blåbäck, Ludvig, Khalil, Gilbert January 2016 (has links)
Syfte – Under detta examensarbete har en vidareutveckling av Cyklop Teknik AB:s existerande produkt, CBC Strap Cutter, utförts. Varav det är en maskin som kapar upp emballageband för att minska hur mycket plats avfallet tar upp, speciellt under avfallstransport. Några problemområden hade uppenbarats efter dess introduktion. En av dessa var att tömningen var omständlig då flera onödiga moment behövde utföras innan tömningen kunde ske. Bland annat i form av att lyfta maskinen från avfallstunnan som också vanligtvis agerade som ställning. Sedan efterfrågades en materialsorteringsfunktion, i form av plast och ferromagnetiskt metall, från Cyklop Teknik AB:s håll. Metod – Utförandet av arbetet har fortgått genom att färdigställa en konceptstudie. Först sammanställdes en kravspecifikation [bilaga 1] och ett Gantt-schema [bilaga 3], de var för att ge ett riktmärke för vad som skulle göras och när. Sedan gick arbetet vidare med att göra konkurrensanalyser och förstudier. Det var för att observera hur konkurrenter och närliggande industrier hade löst vissa problemområden. Ytterligare etablerades det att ingen konkurrent hade en liknande produkt som kunde sortera ingående material. Därefter utfördes konceptgenerering i form av bland annat Brainstorming för att lösa de nämnda problemområdena. Vidare har de olika koncepten sållats ut genom direkt feedback samt en metod som kallas ”Concept scoring matrix”. Till sist återstod ett enda koncept som vidareutvecklades i CAD-miljö, specifikt i SolidWorks. Resultat – Det slutliga resultatet var ett resultat som hade delats upp i olika underkomponenter. Dessa var skärande maskin, separeringsmodul, ställning och avfallstunna. Den skärande maskinen var just den delen som kapade upp det ingående materialet och den behölls så snarlik till originalet som möjligt. Det var för att låta Cyklop Teknik AB:s maskinpark och processer vara så lik som det redan var. För separeringen utvecklades en modul som använde sig av en roterande magnettub. Anledningen till det var för att det skulle ge Cyklop Teknik AB möjligheten att sälja konceptet med eller utan sortering utan att något annat påverkades. Samtidigt skulle modulen kunna anpassas och säljas för andra områden där snabb sortering av nämnda material skulle behöva utföras. En ställning har också tagits fram för att förenkla tömningen som var en kritisk del av arbetet. Eftersom inga onödiga moment skulle uppstå i så fall. Samtidigt utformades ett koncept på en avfallstunna som kunde också den underlätta tömningen. Avfallstunnan utformades därför med både hjul och truckspår för att erbjuda stora möjligheter för användaren. En enskild tömningsprocess för enbart den utvecklades också för att möjliggöra tömning när den skulle vara upphöjd av en truck. Begräsningar – Detta projekt har endast tagit fram en prototyp i CAD-miljö som skulle kunna utvecklas vidare. Anledningen till det var den korta tidsramen för projektet. Sedan har inga simuleringar eller uträkningar utförts på konceptet för att verifiera och optimera konceptet på varje område. Likaså var det på grund av den korta tidsramen. Ingen kundstudie utfördes inte heller, utan istället fortgick arbetet med information som fåtts från Cyklop Teknik AB. / Purpose - In this thesis a further development of Cyklop Teknik AB's existing product, CBC Strap Cutter, has been developed. The product is a machine that cuts packaging tape to reduce the amount space the waste takes up, especially during waste transports. Some problem areas had been revealed after the market introduction of the product. One of these problems was that several unnecessary steps had to be performed before the waste bin could be emptied. One of these step was lifting the machine from the waste bin who also acted as a rack of sorts. A material sorting function, for plastics and ferromagnetic metals, was also requested by Cyklop Teknik AB. Method – The work has been performed by completing a concept study. First a requirement specification [appendix 1] and a Gantt chart [appendix 3] was developed to provide a benchmark for what should be done and when. The work that followed thereafter was a competitive analysis supplemented by a pre-study. The purpose of these studies was to observe how the competitors and related industries had solved these and related problems. Results from the studies that was performed made it clear that no competitor had a similar product that could sort the materials. Brainstorming was thereafter performed to develop new ideas as a help to solve the aforementioned problems and to generate new concepts. Furthermore, the most appropriate concepts was selected through direct feedback from Cyklop Teknik AB among others and a method called "Concept Scoring Matrix". Finally one concept remained and was further developed in a CAD environment, specifically in SolidWorks. Results - The final result was a concept that had been divided into different sub-components. These were cutting machine, separation module, rack and waste bin. The cutting machine was the part cut up the input material. This in turn was kept as close to the original machine as possible and only acquired minor adjustments. In doing so Cyklop Teknik AB's manufacturing processes could remain similar as they have been. A module was developed for the separation, it in turn was constructed with a spinning magnetic tube. The reason for this was that it would give the company possibility of selling the concept with or without the sorting module and its function. At the same time the module could be adapted and sold for other areas where fast sorting of said material would need to be performed. A rack has also been developed to simplify the vacating of the waste bin that was a critical part of the work. In doing so there would be no unnecessary moments that had to be performed. A waste bin was also designed with both wheels and forklift slots to facilitate emptying and offer great opportunities for the user. A single emptying process was developed and made it possible to empty the waste bin when it would be hoisted by a forklift. Restrictions - This project has only developed a prototype in CAD that in turn could be developed further. The reason for this was the short time frame that was allocated for the thesis. No simulations or computations were either performed to validate and optimize the concept in each area. Likewise, it was because of the short time frame. No customer study has been conducted, the work has instead been based on the information received from the Cyklop Teknik AB.
2

Senior primere leerlinge se begrip van sekere algemene getaleienskappe, met besondere verwysing na die distributiewe eienskap

Vermeulen, Cornelis Franz January 1991 (has links)
ENGLISH ABSTRACT: Number properties, amongst others the commutative, associative and distributive properties and general rearrangement principles, form the building blocks of manipulative algebra. Research and observation have shown that sec~mdary school pupils do not sufficiently master manipulative algebra, i.e. they do not possess sufficient mastery towards the nature, meaning, functionality and logic of algebraic manipulations. They are hence not aware that algebraic manipulations are based on the number properties, on the one hand because they were not given sufficient opportunity to experience algebra as generalised arithmetic when they were introduced to algebra, and on the other hand because the number properties, about which young children possess intuitive knowledge, were never explicated for them. This study investigates the level of awareness of several number properties present in senior primary (especially standard 3) pupils, and utilises a few activities to attempt to lead pupils towards a higher level of awareness. In addition this study attempts to determine whether pupils who follow the experimental primary mathematics curriculum (project pupils) possess a higher level of awareness than pupils who follow the traditional curriculum (nonproject pupils). As part of the latter effort, two investigation methods are utilised with regards to specifically the distributive property, i.e. clinical interviews and questionnaires. This also serves as part of a wider effort to design a measuring instrument with which possible differences between the learning outcomes of project and non-project pupils can be measured .. From the results of this study, it seems to appear that the large majority of pupils are explicitly aware of the commutative properties of addition and multiplication and the general rearrangement principles, to a lesser extent with regards to a minus sign before brackets, and that there does not exist a significant difference about the level of awareness towards these properties between project and non-project pupils. With regards to the distributive property, there appears to exist a considerable amount of difference in the level of awareness between project and non-project pupils, the first mentioned being the higher. However, the opinion is expressed that the level of awareness among project pupils is not high enough, and that project pupils must be given sufficient opportunity in (at least standards 4 and 5) to explicate this property for themselves. Finally, a model of the levels of awareness, based on results of this study, is proposed. / AFRIKAANSE OPSOMMING: Getaleienskappe, waaronder die kommutatiewe, assosiatiewe en distributiewe eienskappe en algemene herrangskikkingsbeginsels, vorm die boustene van manipulatiewe algebra. Navorsing en waarneming het aan die lig gebring dat hoerskoolleerlinge manipulatiewe algebra nie na behore beheers nie, dit wil se hulle beskik nie oor voldoende beheersing ten opsigte van die aard, betekenis, funksionalteit en logika van algebraise manipulasies nie. Hulle is dus nie daarvan bewus dat algebraiese manipulasies op die getaleienskappe berus nie, enersyds omdat hulle nie tydens die kennismaking met manipulatiewe algebra genoegsaam in die geleentheid gestel is om algebra as veralgemeende rekenkunde te ervaar nie, en andersyds omdat die getaleienskappe, waaroor jong kinders intuitiewe kennis besit, nooit vir hulle geeksplisiteer is nie. Hierdie studie stel ondersoek in na senior primere (hoofsaaklik standerd 3) leerlinge se vlak van bewustheid van enkele getaleienskappe, en benut enkele aktiwiteite om leerlinge na 'n hoer vlak van bewustheid daarvan te probeer lei. Hierbenewens word probeer om vas te stel of daar by leerlinge wat die eksperimentele primere wiskunde-kurrikulum volg (projekleerlinge) 'n hoer vlak van bewustheid aanwesig is as by leerlinge wat die tradisionele kurrikulum volg (nie-projekleerlinge). As· deel van laasgenoemde poging, word twee ondersoekmetod~s gevolg ten opsigte van spesifiek die distributiewe eienskap, naamlik kliniese onderhoude en vraelyste. Dit dien ook as deel van 'n breer poging om 'n meetinstrument te ontwerp waarmee moontlike verskille tussen die leeruitkomste van projek- en nie-projekleerlinge gemeet kan word. Dit wil uit die bevindinge van hierdie studie voorkom asof die oorgrote meerderheid leertinge eksplisiet bewus is van die kommutatiewe eienskappe ten opsigte van optelling en vermenigvuldiging en die algemene herrangskikkingsbeginsels, in 'n mindere mate ten opsigte van die minusteken voor hakies, en dat daar nie 'n noemenswaardige verskil in die vlak van bewustheid oor hierdie eienskappe by projek- en nie-projekleerlinge bestaan nie. Sover dit die distributiewe eienskap betref, lyk dit asof daar 'n redelike verskil in die vlak van bewustheid by projek- en nie-projekleerlinge is met eersgenoemde die hoogste. Tog word die mening uitgespreek dat die vlak van bewustheid by projekleerlinge nie hoog genoeg is nie, en dat hulle in minstens standerd 4 en 5 in die geleentheid gestel moet word om hierdie getaleienskap vir hulself te eksplisiteer.
3

The effective use of number sense for assisting students with learningdifficulties

Cheung, Siu-pun., 張兆斌. January 2007 (has links)
published_or_final_version / Education / Master / Master of Education
4

The use of mathematical resources to teach number concepts in the foundation phase

Mntunjani, Lindiwe January 2016 (has links)
Thesis (MEd (Education))--Cape Peninsula University of Technology, 2016. / The poor performance of learners in mathematics has long been a matter of concern in South Africa. One certain fact from the Annual National Assessment (ANA) results is that the problem starts in the Foundation Phase (FP) with number concepts. The aim of this study was to explore how five Foundation Phase teachers located in challenging socio-economic school contexts in the Western Cape used mathematical resources to promote teaching for understanding of the important number concept area in CAPS. These resources included humans, materials, culture and time. The research was located within the interpretive qualitative research paradigm and used a case study approach. The participants in the study included five FP teachers teaching Grades 1 to 3 at two schools in the Western Cape. Data was collected through lesson plan analysis, lesson observations and semi-structured interviews. The data collected was then analysed through the lens of Vygotsky’s socio-cultural theory. Socio-cultural theory maintains that knowledge is best acquired if it is mediated by language, more knowledgeable others and physical tools. Vygotsky believed that knowledge is first acquired interpersonally, then intrapersonally, as learners first learn from others, then internalise or individualise knowledge while going through the four stages of the Zone of Proximal Development (ZPD). The findings of this study revealed that teaching for understanding was often compromised by teaching to enable learners to pass assessments. Teachers understood the importance of using resources to teach number concepts in the Foundation Phase, but inclined to rote teaching with work drills in preparation for assessments such as the Annual National Assessment (ANA) and the systemic assessment. Resources were often used when learners struggled to understand concepts and as calculation tools. This study supports the view from the literature that the way in which resources are used affects the teaching and learning of number concepts. It recommends that teachers should read and follow the CAPS mathematics document, as it clearly states what resources to use and how. This study further recommends that more research on the use of resources to teach mathematics in other content areas should be done.
5

Vehicle Integration between Carl-Gustaf M4 and Trackfire RWS : A concept study on mechanical solutions / Fordonsintegrering mellan Carl-Gustaf M4 och Trackfire RWS : En konceptstudie på mekaniska lösningar

Dietmann, Isabelle January 2020 (has links)
Saab Dynamics is a division of Swedish company Saab AB, offering solutions, products, and services for military defence. Included in the Saab Dynamics portfolio is the Carl-Gustaf recoilless rifle; a man-portable, reusable, anti-tank weapon system. Another Saab produced system is the Trackfire Remote Weapon Station; a remotely operated weapon and sensor system, purposed for use on all types of military platforms. Armoured vehicles used by the Swedish Armed Forces are sometimes equipped with remote weapon stations that aim to provide the vehicle crew with protection, by allowing them to operate the weapons from inside the vehicle. These weapon stations can integrate a selection of different weapons, but there are currently no systems in operation that allow integration of the Carl-Gustaf system. This project was initiated based on a request from the Life Guards, for an integrating system between the Carl-Gustaf M4 and a remote weapon station. The project was conducted at Saab Dynamics, Karlskoga, in cooperation with Karlstad University, and aimed to generate suggestions of vehicle integration between the Carl-Gustaf M4 and a remote weapon station. The project was performed as a product development process, using a systematic method for construction and design to develop concept solutions of an integrating system between Carl-Gustaf M4 barrels, and the Trackfire RWS. The report includes a literature study, performed during a feasibility study, on the three systems: Carl-Gustaf weapon system, remote weapon stations, and wheeled armoured vehicles. Recoil principles and interior ballistics of recoilless rifles are further explained and applied to the study. The feasibility study resulted in a specification of requirements, which was used as a foundation for the concept development.  Concepts of solutions were generated and eliminated using a brainstorming session, a morphological matrix, elimination matrices, and decision matrices. One concept was chosen as the final concept solution; a concept comprised of a construction that enables integration of four Carl-Gustaf M4 barrels on the Trackfire RWS, while dampening the recoil that comes from firing a gun. The construction was modelled and analysed using 3D design and engineering platform 3DExperience. Analyses revealed a strong construction that withstands forces arising when a weapon is operated, yet further analyses on how the construction would manage subjection to long-term vehicle vibration and weapon operation are required. Construction dimension optimisations are encouraged, as well as further development of construction details. Recommendations and suggestions on how to proceed with the system integration are provided as a final part of the report. / Saab Dynamics är en division i svenska företaget Saab AB, som erbjuder lösningar, produkter och tjänster för militärt försvar. Inkluderat i Saab Dynamics porfolio finns granatgevär Carl-Gustaf; ett bärbart, återanvändbart pansarvärnsvapen. Ett annat Saab-producerat system är Trackfire Remote Weapon Station; ett fjärrstyrt vapen- och sensorsystem, ämnat för användning på alla typer av militärplattformar. Pansarfordon som används av Försvarsmakten är ibland utrustade med fjärrstyrda vapenstationer som skyddar fordonsbesättningen genom att låta dem manövrera vapnen inifrån fordonet. Dessa vapenstationer kan integrera ett urval av olika vapen, men för närvarande finns det inget system i drift som tillåter integrering av Carl-Gustaf systemet.  Detta projekt initierades baserat på en begäran från Livgardet, om ett integrerande system mellan Carl-Gustaf M4 och en fjärrstyrd vapenstation. Projektet utfördes på Saab Dynamics Karlskoga, i samarbete med Karlstads universitet, och syftade till att generera förslag på fordonsintegrering mellan Carl-Gustaf M4 och en fjärrstyrd vapenstation. Projektet utfördes som en produktutvecklingsprocess, och använde en systematisk metod för konstruktion och design för att utveckla konceptlösningar för ett integrerande system mellan Carl-Gustaf M4 eldrör och Trackfire RWS. Rapporten inkluderar en litteraturstudie, som utfördes under en förstudie, om de tre systemen: Carl-Gustaf granatgevär, fjärrstyrda vapenstationer och hjuldrivna pansarfordon. Rekylprinciper och inre ballistik hos granatgevär förklaras vidare och appliceras i studien. Förstudien resulterade i en kravspecifikation, som användes som grund för konceptutvecklingen. Konceptlösningar genererades och eliminerades genom användning av en brainstorming session, en morfologisk matris, elimineringsmatriser och beslutsmatriser. Ett koncept valdes ut som den slutliga lösningen; ett koncept bestående av en konstruktion som möjliggör integrering av fyra Carl-Gustaf M4 eldrör på Trackfire RWS, samtidigt som den dämpar rekylen som uppstår vid skjutning av ett eldrör. Konstruktionen modellerades och analyserades i 3D-design- och teknikplattformen 3DExperience. Analyser avslöjade en stark konstruktion som motstår de krafter som uppstår vid användning av ett granatgevär, dock är fortsatta analyser av hur konstruktionen skulle klara att utsättas för fordonsvibrationer och gevärsanvändning under en längre period nödvändiga. Optimering av konstruktionsdimensioner uppmuntras, så som fortsatt utveckling av konstruktionsdetaljer. Rekommendationer och förslag på hur arbetet med systemintegrationen kan fortsättas presenteras i slutet av rapporten.
6

A Concept Study for Extraterrestrial Sea Exploration of Titan Via Deployable and Versatile Instrument Device (David) Buoys

Smith, Mary Kate 12 August 2016 (has links)
Saturn’s moon, Titan, has been a scientific marvel since Cassini’s flyby discovered methane-ethane lakes in the northern hemisphere. Several science missions to explore these lakes have been proposed, but none have been launched. Using these previous mission designs, as well as the success of the Huygens probe, this paper will discuss the development of a deployable multi-buoy system with the intent of studying the methane-ethane lakes. The buoys will study the chemical makeup of the lakes, determine meteorology of Titan atmosphere, and map the depth and floor of the targeted lakes. This thesis is a concept study on the multi-buoy system that reviews briefly the concept and design.
7

Väderskydd av ett avgastorn till en testcell för jetmotorer / Weather protection of an exhaust tower for a jet engine test cell

Franzén-Hildeman, Johan, Persson, Joel January 2021 (has links)
Syftet med detta arbete har varit att genomföra en konceptstudie av en teknisk lösning för öppning och stängning av en testcells avgastorn. Detta som en del av det projekt som omfattar ombyggnation av testcellens utlopp. Frågeställningen som studien skall svara på är om det lönar sig att ha en lucka på tornet med hänsyn till det skydd den kan erbjuda och den ekonomiska kostnaden. De mål som sattes upp var att framställa en lämplig kravspecifikation, framställa minst ett fullständigt koncept, framställa en jämförelsematris, föreslå en lösning att ta till förstudie och ge förslag på fortsatt arbete till förstudien. Konceptmetodiken har hämtats från den metod som SAAB använder sig av i utvecklingsprojekt men har modifierats aningen av författarna. Intressenterna till testcellen står i fokus för att framställa en kravspecifikation utifrån deras behov. Intervjuer genomfördes med intressenter och sakkunniga för att erhålla uttalanden. Dessa uttalanden skulle sammanställas och användas som en del av underlaget till en rekommendation. Ett iterativt arbetssätt användes i konceptgenereringen där koncept framställdes och dess funktion utvärderades. De koncept som togs vidare utvärderades mot de identifierade behoven och mot varandra i ett antal jämförelsematriser. Den ekonomiska prognosen byggdes på uppskattade värden och historisk data för kostnader. En övervägande del av intressenterna och sakkunniga som intervjuats har varit positivt inställda till att ha en lucka på avgastornet. Framförallt för det utökade skydd det bidrar med och den potentiellt förlängda livslängden. Kravspecifikationen utformades på ett sådant sätt att det skulle fungera som ett styrdokument för studien, men också innehålla tillräckligt med information för att ge en översiktlig bild av problemet vid överlämning. Tre slutgiltiga koncept presenterades varav ett rekommenderas att ta vidare till förstudie, med motiveringen att den uppfyllde kravet på funktionalitet bäst. Det var även en känd lösning så livscykelanalysen hade en högre grad av säkerhet. / The purpose of this work has been to carry out a concept study of a technical solution for opening and closing a test cell's exhaust tower. This is a part of the project that includes rebuilding the test cell outlet. The question that the study will answer is whether it pays to have a hatch on the tower with regard to the protection it can offer and the financial cost. The goals that were set were to produce an appropriate requirements specification, produce at least one complete concept, produce a comparison matrix, propose a solution to use for a prestudy and provide suggestions for further work for the prestudy. The concept methodology has been taken from the method that SAAB uses in development projects but has been slightly modified by the authors. The stakeholders in the test cell are the prime focus as the requirements specification is based on their needs. Interviews were conducted with stakeholders and experts to obtain statements. These statements would be compiled and used as part of the basis for are commendation. An iterative approach was used in the concept generation where concepts were produced and its function was evaluated. Suitable concepts were evaluated against the identified needs and against each other in a number of comparison matrices. The economic forecast was based on estimated values and historical data for costs. A predominant part of the interviewed stakeholders and experts were positive about having a hatch on the exhaust tower. Mainly because of the increased protection it would contribute and the potential extension of the towers lifespan. The requirements specification was designed to function as a control document but also contain enough information to provide an overview of the problem for the handover to the prestudy. Three final concepts were presented, one of which is recommended for further study, with the justification that it best met the requirement for functionality. It was also a known solution so the life cycle analysis had a higher degree of certainty.
8

Verhoging van laerskoolleerlinge se vlak van bewustheid van die distributiewe eienskap in rekenkunde

Vermeulen, Cornelis Franz January 1995 (has links)
Thesis (DEd)--Stellenbosch University, 1995. / ENGLISH ABSTRACT: The rationale for this study essentially is the perceived and reported misconceptions in algebra that exist within pupils in the Junior Secondary phase. These misconceptions are the direct result of the incomplete mastery of algebra. The purpose of this research is to attempt to contribute towards pupils' complete mastery of algebra and the ensuing elimination of certain pupil misconceptions, by trying to increase primary school pupils' level of awareness of the general number properties. Primary school pupils who learn arithmetic in a problem based environment intuitively use the general number properties to execute arithmetical calculations, while pupils in the traditional teaching approach are taught standard algorithms which they must apply, often without comprehension. In the latter, the existence of the number properties is concealed. When these pupils officially encounter the general number properties for the first time in standard 4 or 5, they are probably not capable of integrating these new concepts into their existing knowledge structure. This may lead to incomplete mastery and ensuing misconceptions, which can become worse when pupils must apply exactly the same number properties in algebra to execute algebraic manipulations. The fact that primary school pupils in the problem based approach intuitively apply the number properties, earlier led to the hypothesis that these pupils possess a higher level of awareness of the number properties. However, research has indicated that these pupils possess only a moderately higher level of awareness. This has led to this study during which a specific attempt is made to take pupils' intuitive knowledge of the number properties, which they spontaneously apply, as a point of departure, and to develop it to such an extent that they become explicitly aware of the existence and nature of these fundamental concepts in mathematics. The technique how to link up with pupils' intuitive knowledge and to increase their level of awareness of the number properties inside a problem based environment, was developed during the first two years of this study. At the end of this period, a suitable teaching strategy was formulated. This strategy is essentially based on the following parameters: Group discussion, the use of calculators, and creating a cognitive disequilibrium. During the third year of this study this strategy was implemented at a number of schools. During this phase research concentrated on the distributive property only. Judging by the results, it appears as if a considerable increase in level of awareness has taken place within these pupils. During this study a hierarchical model of levels of awareness was also formulated. This model was used as a guide in the attempt to increase pupils' level of awareness of the number properties. / AFRIKAANSE OPSOMMING: Die rasionaal vir hierdie studie is hoofsaaklik gelee in die waargenome en gerapporteerde wanbegrippe in algebra wat by leerlinge in die Junior Sekondere fase bestaan. Hierdie wanbegrippe is die direkte gevolg van die onvolledige beheersing van algebra. Die doel van hierdie navorsing is om 'n hydrae te probeer lewer tot leerlinge se volledige beheersing van algebra, en die gepaardgaande uitskakeling van bepaalde leerlingwanbegrippe, deurdat gepoog word om laerskoolleerlinge se vlak van bewustheid van die algemene bewerkingseienskappe te verhoog. Laerskoolleerlinge wat probleemgebaseerde rekenkunde-onderrig ontvang, benut intu'itief die algemene bewerkingseienskappe ten einde rekenkundige berekeninge uit te voer, terwyl aan laerskoolleerlinge in die tradisionele onderrigbenadering standaardalgoritmes onderrig word wat hulle dikwels sonder begrip moet toepas. In laasgenoemde geval word die bestaan van die bewerkingseienskappe erg versluier. Wanneer hierdie leerlinge in standerd 4 of 5 vir die eerste keer amptelik met die algemene bewerkingseienskappe in aanraking kom, is hulle waarskynlik nie in staat om hierdie nuwe begrippe met hul bestaande kennisstruktuur te integreer nie. Dit kan tot onvolledige beheersing en gevolglike wanbegrippe lei, wat kan vererger wanneer leerlinge presies dieselfde eienskappe in algebra moet benut ten einde algebra!ese manipulasies uit te voer. Die feit dat laerskoolleerlinge in die probleemgebaseerde benadering intu'itief die bewerkingseienskappe toepas, het tevore reeds tot die hipotese dat hierdie leerlinge oor 'n hoer vlak van bewustheid van die bewerkingseienskappe beskik, aanleiding gegee. Navorsing het egter aangetoon dat daar slegs 'n matige hoer vlak van bewustheid by hulle bestaan. Dit het tot hierdie studie aanleiding gegee waartydens spesifiek gepoog word om leerlinge se intuitiewe kennis van die bewerkingseienskappe wat hulle spontaan aanwend ten einde rekenkundige bewerkings uit te voer, as vertrekpunt te neem, en te ontwikkel sodat hulle eksplisiet bewus sal raak van die bestaan en wese van hierdie grondliggende waarhede in wiskunde. Die tegniek hoe om by laerskoolleerlinge se intui'tiewe kennis aan te sluit en hul vlak van bewustheid van die bewerkingseienskappe binne 'n probleemgebaseerde omgewing te verhoog, is gedurende die eerste twee jaar van hierdie studie ontwikkel. Aan die einde van hierdie periode is 'n toepaslike onderrigstrategie geformuleer. Hierdie strategie steun sterk op die volgende parameters: Groepsbespreking , die benutting van sakrekenaars, en die skep van 'n kognitiewe disekwilibrium. Gedurende die derde jaar van hierdie studie is hierdie onderrigstrategie in verskeie skole toegepas. Daar is gedurende hierdie fase slegs op die distributiewe eienskap gekonsentreer. Volgens die resultate wil dit voorkom asof daar 'n aansienlike verhoging in die betrokke leerlinge se vlak van bewustheid van die distributiewe eienskap plaasgevind het. Gedurende hierdie studie is ook 'n hierargiese model van vlakke van bewustheid geformuleer aan die hand waarvan die poging aangewend is om leerlinge se vlak van bewustheid van bewerkingseienskappe te verhoog.
9

Driveline : Moving infantry target (MIT)

Hjortman, Robin, Harrysson, Kristian January 2016 (has links)
This report is part of a bachelor thesis implemented at Saab training systems AB in Huskvarna. It treats the concept development of the driveline on Moving infantry target, MIT. Today Saab has a problem in the shape of that their customers uses the wrong moment when tightening the cog belt of the driveline. As a consequence the cog belt has a high risk of snapping if it is too tight or pluck off if it is too loose. Thereto the electrical motors used in the MIT has gone out of production. The task boiled down to produce a number of proposals that improves the chucking or driveline solution together with finding a new electrical motor to replace the outdated one. A concept study was made containing detailed examinations together with Saab. To answer the problems questions, several product development methods were used, like Quality function deployment and Pugh’s matrix, to reach a final concept. The last concepts were modeled in a 3D-program for an easier comparison between their feasibility. The chosen solution consisted of two motors that via a gearing actuates the respective axle. By replacing the belt drive and choosing more lubrication free gears the maintenance is expected to be improved. In addition the product price is lowered by careful choices of components. The production of a prototype could not be implemented due to lack of time.
10

Estudo prospectivo e randomizado para avaliar a eficácia e segurança da ablação epicárdica de taquicardia ventricular utilizando cateter irrigado com sensor de contato / Efficacy and safety of epicardial vt ablation using contact force irrigated tip catheter in Chagas disease

Pisani, Cristiano Faria 20 February 2019 (has links)
Introdução: O mapeamento e ablação epicárdico é frequentemente necessário em pacientes com cardiopatia não-isquêmica, especialmente pacientes com doença de Chagas. Entretanto, não existem estudos randomizados provando a sua superioridade em comparação a ablação endocárdica exclusiva. Métodos: Foram selecionados 30 pacientes com doença de Chagas encaminhados para ablação de TV sendo randomizados para (1) ablação endocárdica exclusiva e (2) ablação endo e epicárdica combinada. No grupo combinado a ablação era realizada na superfície que se observava os melhores sinais durante TV ou mapeamento de substrato. No grupo endocárdico exclusivo, a ablação era realizada inicialmente na superfície endocárdica apenas e se não existisse cicatriz ou a TV clínica se mantivesse indutível ocorria a continuação da ablação. O objetivo eficácia foi a não reindutibilidade da TV e segurança foi a taxa de complicações do procedimento. Resultados: A maioria dos pacientes eram do sexo masculino, com idade mediana de 67 (58;70) e 58 (43; 66) anos e FEVE de 31,1 ± 11,5% and 41,0 ± 17%, respectivamente. Ocorreu significativamente menos falhas da ablação no grupo combinado (2/15) em comparação ao grupo endocárcico exclusivo (9/126; P=0,21). A ablação epicárdica foi também realizada em nove pacientes do grupo endocárdico exclusivo devido a ausência de cicatriz endocárdica e manutenção da indutibilidade da TV. Não se observou complicações relacionadas ao procedimento. Conclusão: Neste estudo randomizado de ablação epicárdica e endocárdica de TV em pacientes com Doença de Chagas, ocorreu menos insucesso na ablação quando a estratégia combinada endo e epicárdico foi utilizada. Ambas estratégias foram seguras / Background: Epicardial mapping and ablation are frequently necessary for nonischemic cardiomyopathy, especially in Chagas disease patients. We developed this randomized trial to evaluate the efficacy and safety of combined epicardial ablation in Chagas disease patients. Methods: We randomized 30 patients with Chagas disease into an endocardial-only group or a combined epi and endocardial mapping and ablation group. In the combined group, ablation was performed on the surface with optimal signals during mapping. In the endo-only group, ablation was initially performed only on the endo surface despite of nonoptimal signals. The endpoint was efficacy, measured by ventricular tachycardia reinducibility and safety measured by the rate of complications. For endo-only patients, epicardial ablation continuation was allowed after inducibility was assessed following ablation. Results: Most of the patients were male, the median age was 67 (58; 70) and 58 (43; 66) years-old and LVEF was 31.1 ± 11.5% and 41.0 ± 17%, respectively. There was a significant fewer failure for the combined group (2 in 15 patients) comparing to endo only-group ablation (9/15 patients;P=0,021). Epicardial ablation was also performed in nine patients in the endo group after ablation failure due to an absence of endocardial scar and maintenance of VT inducibity. There were no complications related to the epicardial access or ablation. Conclusions: In this randomized trial of epicardial and endocardial VT ablation in Chagas disease, there was less failure of ablation when a combined endo/epi approach was used. Both approaches were safe

Page generated in 0.0591 seconds