This master thesis was conducted during the spring of 2024 at Väderstad AB. Väderstad manufactures agricultural machines, including two types of seed drills used to plant seeds: conventional seed drills and precision planters. The primary difference lies in the seed dispensing unit, which distributes the seeds from storage before planting. Conventional seed drills utilize randomness to distribute seeds, while precision planters use a complex unit that dispenses seeds one by one. The precision seed dispensing unit comes at a higher cost and requires more space, resulting in wider row spacing compared to conventionalseed drills. A low row distance is desired to maximize crop yield. This master thesis aims to develop a seed dispensing unit which can be used for a new type of seed drill. The seed dispensing unit intends to be smaller and less costly than the ones for precision planters, while achieving a better seed distribution than the conventional seed drills. The product development was carried out through a tailored process for this project, incorporating methods such as Blackbox, Brainwriting, and Pugh’s concept selection matrix. The process generated three concepts which were modeled in CAD and printed using a 3D printer. The models underwent functional assessment and seeding capacity testing, followed by redesign, reprinting, and testing in an iterative process. The master thesis resulted in two concepts which were presented for Väderstad. The first prototype consisted of a wheel with indentations. As the wheel rotated, the indentations picked up seeds and then released them into an airflow-assisted seed transport which sent the seeds into the ground. The second prototype featured a vertical screw that rotated upwards, distributing seeds evenly against the wall. This prototype also used an airflow-assisted seed transport. Presently, Väderstad has submitted a patent application for the screw concept and will continue its development within the company. / Detta examensarbete utfördes under våren 2024 hos Väderstad AB. På Väderstadtillverkas två typer av såmaskiner som används till fröplantering: konventionella såmaskiner samt precisionssåmaskiner. Den primära skillnaden mellan såmaskinerna är fröutmatningsenheten som används till fördelning av utsäde från sålådan innan plantering. I konventionella såmaskiner används slumpen till fördelningen, medan i precisionssåmaskiner används en komplex enhet där fröna matas ut ett i taget. Precisionssåmaskinens fröutmatningsenhet är dyrare samt större. Dess storlek begränsar avståndet mellan raderna där fröna planteras. Således blir radavståndet för precisionssåmaskinen större än för konventionella såmaskinen. Egentligen eftersträvas låga radavstånd för maximal avkastning på skörden. Examensarbetet syftades till att utveckla en fröutmatningsenhet som kan användas i en ny typ av såmaskin. Fröutmatningsenheten ämnades att vara mindre och billigare än den i precisionssåmaskinen, samtidigt som den uppnår en bättre fröfördelning än den konventionella såmaskinen. Produktutvecklingsmetoden anpassades efter projektet, den använde metoder som Blackbox, Brainwriting och Pughs konceptvalsmatris. Processen genererade tre koncept som modellerades i CAD och skrevs ut med en 3D-skrivare. Modellerna genomgick funktionellbedömning och testning av utmatningskapacitet, följt av omkonstruktion, ny 3D-utskrift och testning i en iterativ process. Utifrån produktutvecklingsprocessen genererades två koncept med prototyper. Den förstaprototypen bestod av ett hjul med fack. När hjulet roteras förbi fröbehållaren fångasutsädet i facken. Därefter släpps utsädet i en luftassisterad frötransport som transporterardet till marken. Den andra prototypen bestod av vertikal skruv som drivs uppåt. Utsädettrycks då ut mot skruvens vägg vilket gör att det fördelas jämnt. När fröna matas ut ur skruven plockas de upp av en luftassisterad frötransport som för dem till marken. Idag har Väderstad patentansökt den sistnämnda idéen och kommer fortsätta utveckla den inomföretaget.

Den ökande efterfrågan på högre produktkvalitet inom tillverkningsindustrin kräver hög stabilitet och lång livslängd på borrverktyg under borrningbearbetningsprocessen. En metod för att öka produktkvaliteten och därmed förlänga livslängden på borrverktyg är skäreggpreparering. Skäreggpreparering används för att skapa en kantgeometri som ger borrverktyget både en bättre styrka och högre tålighet mot slitage. Det mest förekommande slitaget på borrverktyg är fasförslitning och det utvecklas snabbt under den initiala slitningsperioden under borrens livslängd. Syftet med det här examensarbetet var att genom flerfaktorförsök undersöka hur skäreggprepareringsprocessen kan förbättras för att minska fasförslitning under den initiala slitningsperioden på belagda hårdmetallborrar. Skäreggprepareringsprocessen studerades som en fallstudie på Scania Motorbearbetning. Fallstudien genomfördes efter problemlösningsmetodiken DMAIC (Define, Measure, Analyse, Improve och Control) som inkorporerade försöksplanering, vilket medförde att två ytterligare faser tillkom: Pre-analyze och Experiment. Datainsamlingen bestod av både kvalitativ och kvantitativ data. Den kvalitativa datan erhölls från intervjuer under Measure-fasen och den kvantitativa datan erhölls från det genomförda experimentet under Experiment-fasen, som sedan analyserades i Analyze-fasen. Baserat på litteraturstudien, nulägesbeskrivningen och intervjuerna bestämdes försöksfaktorerna till processtid, borrens djup i slipmedel, rotationsriktning på rotor och rotationshastighet på spindel samt responsvariablerna till skäreggradie och total fasförslitning. Försöksfaktorerna testades i ett fullständigt tvånivåers faktorförsök med 4 faktorer och 4 centrumpunkter. Analysen av resultaten från experimentet visade att korrelationen mellan responsvariablerna var försumbar under den initiala slitningsperioden. Vidare identifierades inte några signifikanta effekter baserade på responsvariabeln total fasförslitning. Däremot kunde det konstateras att de försöksfaktorer som påverkade responsvariabeln skäreggradie var processtid, borrens djup i slipmedel och rotationsriktning på rotor. En optimeringsmodell togs fram i Improve-fasen för att optimera skäreggprepareringsprocessen med avseende på skäreggradie. Optimeringen utgick från att ha en stor skäreggradie under förutsättningen att den nuvarande processtiden halveras. Optimeringsmodellen kunde inte bekräftas, därför togs en rekommendation fram som beskriver stegen för att bekräfta den framtagna optimeringsmodellen. Vidare togs två ytterligare rekommendationer fram med syfte att undersöka skäreggprepareringsprocessen med avseende på andra typer av slitage samt undersöka verktygsslitage under verktygets fulla livslängd. I Control-fasen togs en kontrollplan fram som stöd för att kontrollera rekommendationerna. Avslutningsvis bidrog det här examensarbetet med nya insikter och slutsatser om utveckling av fasförslitningen under den initiala slitningsperioden under en borrs livslängd. / The increasing demand for higher product quality in the manufacturing industry requires high stability and long service life of drilling tools during the drilling process. One method of increasing product quality and thus extending the tool life for drills is cutting edge preparation. Cutting edge preparation is used to create an edge geometry that gives the drilling tool both better strength and higher resistance to wear. The most common wear on drill tools is flank wear that develops rapidly during the initial wear period of the drill's life. The purpose of this thesis was to investigate how the cutting edge preparation process can be improved by factorial design in order to reduce flank wear during the initial wear period on coated solid carbide drills. The cutting edge preparation process was studied as a case study at Scania's motor processing department. The case study followed problem-solving methodology DMAIC (Define, Measure, Analyze, Improve and Control) incorporating design of experiments. This resulted in two additional phases: Pre-Analyze and Experiment. Data collection consisted of both qualitative and quantitative data. The qualitative data were obtained from interviews during the Measure phase and the quantitative data was obtained from the experiment conducted during the Experiment phase, which was later analyzed in the Analyze phase.     Based on a literature study, current description, and interviews, the identified experimental factors were process time, depth in the grinding granulate, rotational direction of the rotor, and rotational speed of spindle. The identified response variables were cutting edge radius and total flank wear. The experimental factors were tested in a full two-level factorial design with 4 factors and 4 center points. The analysis of the results from the experiment showed that the correlation between the response variables was negligible during the initial wear period. Furthermore, no significant effects could be found based on the response variable total flank wear. However, it was found that the experimental factors that influenced the response variable cutting edge radius were process time, depth in grinding granulate, and direction of rotation of the rotor. An optimization model was developed during the Improve phase to optimize the cutting edge preparation process in regards to the cutting edge radius. The optimization was based on generating a large cutting edge radius and at the same time reducing the current process time by half. The optimization model could not be confirmed; therefore, a recommendation was developed outlining the steps to confirm the optimization model. Furthermore, two additional recommendations were made to investigate the cutting edge preparation process concerning other types of wear and to examine tool wear during the tool’s full life. A control plan was developed in the Control phase to help to control the recommendations. In conclusion, this thesis contributed new insights and conclusions on the development of flank wear during the initial wear period during the tool life.

As a result of the increase of digitalisation in today’s society, the Swedish school system requires a certain degree of digital competence amongst teachers, affecting the foundation of how their teaching practice is structured. Therefore, this study aims to investigate to what extent Swedish EFL/ESL teachers in the primary years incorporate digital tools in their teaching practice, and more specifically how – and why – they are used to facilitate learners’ vocabulary acquisition/learning. In this qualitative study, five Swedish EFL/ESL teachers in the primary years participated. The five participants work at five different schools, in three different municipalities. The empirical data was collected through semi-structured interviews. The results of these indicate that vocabulary drills, generally given as homework, are the primary method of teaching English vocabulary to the EFL/ESL learners, requiring them to learn consciously and intentionally. Moreover, the results imply that a variation of tasks and teaching tools, as well as a frequency in exposure of content, is necessary for beneficial vocabulary acquisition/learning. Further, it is evident that digital tools have a profitable effect on learners’ motivation and consequently their learning. Finally, it is clear that what matters when incorporating digital tools is how they are used, rather than that they are used.

In the light of almost daily media reports of accidents and incidents of violence in South African schools, it can be assumed that most South African schools are unsafe. This study investigates the manner in which rural public schools implement the school safety regulations prescribed by the South African Schools Act to ensure learner safety. This qualitative study investigates the implementation of the Schools Act’s safety regulations at four public schools situated in the rural areas east of Pretoria in Gauteng. Data was gathered using interviews with the principals of these schools as well as by the observation and recording of the normal day-to-day activities at the school and by an analysis of each school’s school safety policy. The interviews with the principals focused on the manner in which each school implements the regulations for school safety in areas such as access to the school and the conducting of searches, the arranging of trips and excursion and the planning and managing water-based activities and the early release of learners. Observation at each of the four schools focused on the physical condition of the school and the schools’ procedures for playground duty, fire fighting and emergency drills. The analysis of each school’s safety policy aimed to determine the compliance of these policies with the Schools Act regulations and to determine the practicability and effectiveness of each policy. The researcher’s conclusions include the fact that none of four schools had an effective and practicable school safety policy in place and were not implementing their inadequate policies effectively. He suggests among other things a comprehensive compulsory school safety training programme including aspects such as information on the intent, content and aims of the school safety regulations, the concepts of liability and negligence and methods for drafting, adopting and implementing effective school safety policies. Copyright / Dissertation (MEd)--University of Pretoria, 2009. / Education Management and Policy Studies / unrestricted

Säkerhetsövningar på fartyg är en central del i verksamheten ombord. Genom övningar kan besättningen förbättra sina kunskaper, och vara beredd på eventuella nödsituationer. Studien syftar till att undersöka och finna faktorer som påverkar besättningens intresse samt motivation kopplat till övningar. Studien genomförs som en kvalitativ intervjustudie med sex svenska nautiska befäl inom handelssjöfarten. Studien använder sig utav ett experturval, detta ansågs vara fördelaktigt då urvalsgruppen bidrar till relevant information för att besvara studiens frågeställningar. I studien har det framkommit att motivationsbrist kan vara ett problem under övningar, vilket är något som måste tas i åtanke när en övning planeras och genomförs. Motivationsbristen kan exempelvis bero på att besättningsmedlemmen upplever att övningar är repetitiva, görs på besättningsmedlemmens lediga tid och att den som håller i övningen också kan vara omotiverad. Befälen spelar en viktig roll i hur utfallet av övningen blir, beroende på deras inställning till övningarna. Med förståelse om att problemet existerar finns det enligt befälen tekniker för att öka motivationen, till exempel ett quiz eller en tipspromenad. Resultaten av studien förväntas medverka till att ge en större förståelse kring motivationens faktor när det kommer till övningar. Med en större förståelse kring motivationens inverkan, kan övningar utvecklas för att öka motivationen och deltagandet hos besättningen. / Ship safety drills are a central part of shipboard operations. Through drills, the crew can improve their knowledge and be prepared for possible emergencies. The study aims to investigate and find factors that affect the crew's interest and motivation linked to drills. The study is conducted as a qualitative interview study with six Swedish nautical officers in merchant shipping. The study uses an expert sample, this was considered advantageous as the sample group contributes to relevant information to answer the study's questions. The study has shown that lack of motivation can be a problem during drills, which is something that must be considered when a drill is planned and carried out. The lack of motivation may, for example, be due to the crew member feeling that drills are of a repetitive nature, are done in the crew member's free time, and that the person conducting the drill may also be unmotivated. The officers play an important role in the outcome of the drill, depending on their attitude towards the exercises. With the understanding that the problem exists, there are, according to the officers, techniques to increase motivation, for example a quiz or a point walk. The results of the study are expected to contribute to a greater understanding of the factor of motivation when it comes to shipboard drills. With a greater understanding of the impact of motivation, exercises can be developed to increase the motivation and participation of the crew.

Disputats. Universität Hohenheim, 2005.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this work was to evaluate the tractor/toolholder operating performance equipped with different configurations of the cutting elements of crop residues and soil breakers, depending on the speed. This was done in a farm located in the municipality of Santa Maria (Rio Grande do Sul). The experimental area's soil was classified as Red Alfisol and loamy sand texture. The experiment consisted of 24 treatment combinations in a factorial scheme 2x3x4. These were composed by the interaction of mechanisms factors of furrow opening (furrow opener fixed and rotary), cutting crop residues (without hard, smooth and fluted disc) and travel speeds (1.11, 1.67, 2.22 and 2.78 m s-1). Farm's performance data tractors were acquired with the use of electronic instrumentation. The associations between furrow opener and disc showed better performance at speeds of 1.11 and 1.67 m s-1 for required lesser traction force, power in the bar and fuel consumption. Furthermore, the cutting discs use allowed a reduction of increased demand traction force when the speed went from 1.11 to 2.78 m s-1. The furrow shanks required greater demand traction than mismatched drives and both, when combined with the cutting discs, had increased their demand with greater significance for association with fluted disc. The proportionality of this variable was proved with the hourly consumption and the splipping. The soil mobilization was not influenced by the speed, being higher with the use of the shank, and among the combinations with disc, it was superior to fluted. / O objetivo geral deste trabalho foi avaliar o desempenho operacional do conjunto trator/porta-ferramentas equipado com diferentes configurações dos elementos de corte dos resíduos culturais e de rompedores do solo, em função da velocidade de deslocamento. Este foi realizado em propriedade agrícola situada no município de Santa Maria (Rio Grande do Sul). O solo da área experimental foi classificado como Argissolo Vermelho e textura franco arenosa. O experimento foi composto por 24 combinações de tratamentos, em um esquema fatorial de 2x3x4. Estes foram compostos pela interação dos fatores mecanismos de abertura de sulco (sulcador fixo e rotativo), corte de resíduos culturais (sem disco, disco liso e ondulado) e velocidades de deslocamento (1,11, 1,67, 2,22 e 2,78 m s-1). Os dados de desempenho do trator agrícola foram adquiridos com a utilização de instrumentação eletrônica. As associações entre sulcador e disco apresentaram melhor desempenho nas velocidades de 1,11 e 1,67 m s-1 por demandaram menor força de tração, potência na barra e consumo de combustível. Além disso, a utilização de discos de corte permitiu uma redução da ampliação da demanda de força de tração quando a velocidade passou de 1,11 para 2,78 m s-1. O sulcador haste exigiu maior demanda de tração do que os discos desencontrados e ambos, ao serem combinados com os discos de corte, tiveram suas demanda aumentadas com maior significância para a associação com o ondulado. Foi comprovada proporcionalidade desta variável com o consumo horário e o patinamento. A mobilização do solo não foi influenciada pela velocidade, sendo maior com o uso da haste e, dentre as combinações com disco, foi superior para o ondulado.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais / The aim of this work is to determine the life of twist drills used for dental implantology when drilling bovine tibia bones and to study the influence of the cutting conditions. The inputs variables considered were the cutting tool material, the feed velocity and the spindle speed. The outputs variables monitored were the number of drilled holes, the workpiece temperature, the thrust force and the tool wear. The tests were carried out in a CNC machine center and the cutting parameters were varied following a 23 experimental design. Three types of uncoated tool materials were used, a martensitic stainless steel (M340/Böhler), an austenitic stainless steel (AISI 316L) and a ceramic (zircon stabilized with Y2O3). The tool lives were expressed by the number of drilled holes considering a limit of the workpiece temperature of 47ºC, used as the end of tool life criterion. The temperatures were monitored by using three thermocouples of the type T (cupper-constantan) inserted in the work material samples, positioned very close to the drill wall. The thrust force was measured with a Kistler rotating dynamometer. A data acquisition board and a computer were used for automation of the measurement system. A mixture of 20% of car radiator fluid and water was applied as coolant (irrigation) with a flow rate of 160 ml/min. The results showed that the martensitic stainless steel outperformed the austenitic stainless steel and the ceramic material. The lowest temperatures and a conformity state at the clinic standard for thrust force values were obtained with the highest cutting parameters (45 mm/min and 2500 rpm). It was observed that the higher feed velocity promoted a temperature drop, while the higher spindle speed decreased the thrust force. / O objetivo deste trabalho é determinar a vida de brocas para implantodontia através de furação em tíbia bovina e estudar a influência das condições de corte utilizadas. As variáveis de entrada do trabalho foram o material de ferramenta, a velocidade de avanço e a rotação. E as variáveis de saída monitoradas foram o número de furos realizados, a temperatura próxima à parede óssea, a força de avanço e o desgaste das ferramentas. Os testes foram executados em um Centro de Usinagem variando os parâmetros de corte seguindo um planejamento experimental 23. Três tipos de materiais de ferramenta não revestidos foram utilizados, um aço inoxidável martensítico (M340/Böhler), um aço inoxidável austenítico (AISI 316L) e um cerâmico (zircônia estabilizada com Y2O3). A vida da ferramenta foi expressa pelo número de furos realizados considerando como critério de fim de vida a temperatura na peça igual a 47ºC. As temperaturas foram monitoradas pelo uso de três termopares do tipo T (cobre-constantan) inseridos no corpo-de-prova e posicionados próximo à parede do furo. A força de avanço foi medida com um dinamômetro rotativo Kistler. Uma placa de aquisição de dados e um computador foram utilizados para a automação do sistema de medição. Uma mistura de 20% de líquido de arrefecimento automotivo foi utilizada como refrigerante (irrigação) a uma vazão de 160 ml/min. Os resultados mostraram que o aço inoxidável martensítico superou o aço inoxidável austenítico e o material cerâmico. Menores temperaturas e um estado de conformidade aos padrões clínicos para valores de força de avanço foram obtidos com os maiores parâmetros de corte (45 mm/min e 2500 rpm). Observou-se que velocidade de avanço alta promove principalmente a queda da temperatura, enquanto a rotação elevada à queda na força de avanço. / Mestre em Engenharia Mecânica

Mechanical vibrations are inevitable in drilling operations. Torsional stick-slip vibrations are vibrations that occur in drilling columns, which are produced by periodic variations of torque and characterized by large fluctuations in the speed of the drill bit. These vibrations are dangerous, primarily by the cyclical characteristic of the phenomenon that by the amplitude of the same, which can cause fatigue of the pipe, failures in the components of the drill string, deformations in the walls of the well, excessive wear of the drill, low rate of penetration, and collapse of the drilling process. The frequency of these unwanted oscillations can be reduced by the application of automatic control techniques. The objective of this study is to evaluate through numerical simulations, the application of conventional control techniques, such as proportional-integral control (PI), and nonlinear, as the sliding mode control (SMC) and the input-output linearization control (IOLC), to eliminate the presence of stick-slip oscillation in drilling columns. The controllers are designed primarily to maintain a constant speed of rotation system, by manipulating engine torque, thereby inferentially control the speed of the drill, thus providing optimum operation conditions, beyond preserving system stability. Results of simulations using drill string torsional models of two degrees of freedom (2-DOF) and four degrees of freedom (4-DOF) show the performance of the proposed control systems, which are analyzed and qualitatively compared. / Vibrações mecânicas são inevitáveis nas operações de perfuração. Vibrações torcionais stick-slip são vibrações que ocorrem em colunas de perfuração, as quais são produzidas pelas variações periódicas de torque e caracterizadas por grandes oscilações da velocidade da broca. Estas vibrações são prejudiciais, mais pela característica cíclica do fenômeno que pela amplitude da mesma, podendo originar fadiga da tubulação, falhas nos componentes da coluna de perfuração, deformações nas paredes do poço, desgaste excessivo da broca, baixa taxa de penetração e, inclusive, colapso do processo de perfuração. A frequência destas oscilações indesejadas pode ser reduzida pela aplicação de técnicas de controle automático. O objetivo deste trabalho é avaliar, mediante simulações numéricas, a aplicação de técnicas de controle convencional, como o controle proporcional-integral (PI), e não linear, como o controle por modos deslizantes (SMC) e o controle por linearização entrada-saída (IOLC) para eliminar a presença de oscilações stick-slip em colunas de perfuração. Os controladores são desenvolvidos principalmente para manter constante a velocidade do sistema de rotação, mediante a manipulação do torque do motor, para assim controlar inferencialmente a velocidade da broca, fornecendo desta maneira condições ótimas de operação, além de preservar a estabilidade do sistema. Resultados das simulações, usando modelos torcionais de uma coluna de perfuração de dois graus de liberdade (2-DOF) e de quatro graus de liberdade (4-DOF), mostram o desempenho dos sistemas de controle propostos, os quais são analisados e comparados qualitativamente.

This thesis deals with the structural-technical survey of beam bridge no. 204c - M1, located in Bystřice pod Hostýnem. The theoretical part of the thesis is devoted to general characteristics of bridges, load capacity of bridges, beam bridges, concrete reinforcement, concrete, diagnosis of reinforced concrete structures, and laboratory evaluation. The practical part deals with carrying out a structural-technical survey on the bridge mentioned above, its evaluation and assessment, recalculation of the load capacity, and design of the necessary rehabilitation to maintain the functionality of the bridge.