Increasing demands for lower emissions from heavy trucks and buses creates new demands on the components in the engine. One such component is the journal bearing which is used at many positions in the engine. Implementing a start-stop system in a truck engine leads to that the crankshaft journal bearing gets worn out too quickly. A journal bearing is a sliding bearing with a constant flow of oil. When the journal starts rotating an oil film is formed between the bearing and the journal, separating the journal from the bearing surface when the rotational speed is high enough. When this happens a hydrodynamic oil film is formed. During start and stop the bearing and journal passes through boundary and mixed lubrication regimes. The increase in starts and stops leads to a vast increase in the time that the bearing is experiencing boundary and mixed lubrication. During these regimes the journal comes in contact with the bearing surface and eventually leads to wear. This thesis has compared two new materials provided by Höganäs AB with an existing bearing as a reference material. The new materials were laser cladded onto bearing shells and sent to Scania for grinding and testing. The thought was to use a start-stop test rig at KTH that simulates start-stop cycles. The reference bearings were first run in the test rig, but when the shells with the new materials arrived it turned out that they would not fit in the test rig. This created the need for a new test method on a short notice and a reciprocating tribometer at Scania was chosen. The tribometer underwent a number of modifications to be able to fit the samples. Five tests with each new material and the reference material were carried out. The tests ran for 60 minutes except for a long term test that ran for 600 minutes. The results showed that the material designated “S”, which had a solid lubricant, had a coefficient of friction similar to the reference material, but produced less wear and could handle a higher load. The thesis has also proved that the start-stop test rig at KTH works well and can deliver reliable results. / På grund av skärpta miljökrav för tunga lastbilar och bussar ökar kraven på motorns komponenter. En av dessa komponenter är radialglidlager som används på många platser i motorn. Implementering av start-stoppsystem i en lastbilsmotor leder till att vevaxellagren slits ut i förtid. Ett radialglidlager är ett glidlager med ett kontant tillflöde av olja. När axeln börjar rotera skapas det en oljefilm mellan lagerytan och axeln. När rotationshastigheten är tillräckligt hög bär oljefilmen lasten och separerar axeln och lagerytan. Då har det bildats en fullfilm. Under start och stopp passerar lagret genom smörjregimerna gränsskiktssmörjning och blandsmörjning. Ökningen av start och stopp leder till en stor ökning av tiden som lagret upplever gränsskiktsoch blandsmörjning. Under dessa regimer är axeln och lagerytan i kontakt vilket leder till nötning. Detta examensarbete har jämfört två nya material från Höganäs AB med ett existerande lager som referens. De två nya materialen påsvetsades på lagerskålar och skickades till Scania för att slipas och testas. Tanken var att använda en start-stopprigg på KTH som simulerar startstoppcykler. Till att börja med kördes referenslagren i riggen, men när lagerskålarna med de nya materialen levererades visade det sig att de inte passade i testriggen. Detta innebar att en ny testmetod behövdes tas fram med kort varsel och valet föll på en reciprocerande tribometer på Scania. Tribometern var tvungen att modifieras för att proverna skulle passa. Fem test med varje material utfördes. Varje test tog 60 minuter, förutom ett långtidstest som kördes under 600 minuter. Resultaten visade att materialet kallat ”S”, vilket inkorporerade ett fast smörjmedel, hade en friktionskoefficient som liknade referensmaterialets, men producerade mindre nötning och klarade av en högre last. Examensarbetet har också kunnat påvisa att start-stoppriggen på KTH fungerar väl och kan leverera konsekventa resultat.

Background: Start-ups foster economic development, create new jobs and generate economic value. However, most start-ups fail during the development phase. Generally, after five years 80% of the start-ups fail and need to shut down their business. A challenging task that start-ups need to overcome is the labour shortage within the industry. With the existing literature focusing on how business generally can attract employees, a gap in the literature was identified on how start-ups can attract employees.   Purpose: The study’s purpose is to explore how start-ups can work to attract employees during the development phase of the business. Moreover, the aim is to explore why employees are attracted to the start-up industry and how managers work with recruitment.  Method: Semi-structured interviews with nine relevant participants who operate in the start-up environment as managers or employees were performed. The interviews were conducted by using a qualitative method with an inductive approach and data were analysed by using a systematic thematic analysis, which further led to the creation of a conceptual model.   Conclusion: The findings suggest start-ups to implement employer branding to increase the brand’s visibility. The beneficial opportunities associated with start-ups is a factor that would be recommended to prioritise to increase the attraction to the industry. This means that there is space for improvement regarding start-ups attraction. In addition to this conclusion, findings also suggest start-ups to implement a recruitment system.

Background: There is a great interest in researching prescriptive methods as entrepreneurs demand guidance for start-up processes. A learn-by-doing methodology called lean start-up methodology has influenced tech entrepreneurs. Further, design thinking is another methodology for developing innovation that has been suggested to benefit in a software context. The uncertain nature requiring rapid innovation for software start-ups has sparked the interest in exploring the combination of the methodologies in an entrepreneurial context to utilize the benefits of both. However, the methodologies have been criticized due to a lack of rigor. It is therefore an opportunity to explore applicability of lean start-up in practice and design thinking in a software context to develop a unique methodology integrating lean start-up and design thinking.Purpose: The purpose of this study is to explore the occurrence of the two innovation driven methods lean start-up and design thinking in successful software start-ups, to develop a theory of an integrated methodology that utilizes the benefits of both. The intent is to provide explicit guidance for both scholars and entrepreneurs. Methodology: An exploratory qualitative method was used with an inductive approach, conducting semi-structured interviews with six founders of successful software companies. Conclusion:  The findings advance the understanding of the lean start-up methodology in practice, by extending the aspect of idea development and clarifying the use of iterating aspects of the business model. The findings update the sequence of design thinking when applied in a software context and extend the iterating aspect, to adapt to the need for rapid development. The theory of suggested integration confirms that the first stages of design thinking initiate the idea process, emphasizing early consideration of desirability, viability, and feasibility, while lean start-up is integrated into the product development process, emphasizing rapid iterating development for validation.

Die vorliegende Arbeit soll den Nachweis erbringen, dass mit einem spezifi-schen Trainingsprogramm, welches aus einer Kombination von Techniktrai-ningsformen besteht, Teilkörperbewegungen beim Absprung vom Block so op-timiert werden, dass quantifizierbare Verbesserungen im Startabschnitt erzielt werden können. Ausgangspunkt ist die auf Wettkampfanalysen und Leistungsdiagnosemaßnahmen basierende Annahme, dass bei der Mehrheit der deutschen Nationalmannschaftsschwimmer erhebliche Reserven in der Ausführung der Absprungbewegung vom Block bestehen. Die Folge sind Nachteile der deutschen Sportler im Startabschnitt gegenüber der internationalen Konkurrenz. Ein spezielles Techniktrainingsprogramm wird als Trainingsintervention in einer Nachwuchstrainingsgruppe erprobt. Die Intervention erstreckt sich über zehn Wochen. Während der ersten sechs Wochen wird in wöchentlich vier Teiltrainingseinheiten ein Programm zur Sensibilisierung der Teilköperbewegungen absolviert. In weiteren vier Wochen erfolgt wöchentlich einmal ein Messplatztraining. Neun Wochen nach Abschluss des ersten Interventionszeitraumes wird die Intervention wiederholt. Im Vergleich mit einer Kontrollgruppe können über das gesamte Trainingsjahr 2007/2008 für die Interventionsgruppe größere Entwicklungsraten bei den Startleistungsmerkmalen nachgewiesen werden. Die gewonnenen Erkenntnisse unterstreichen die Notwendigkeit eines sorgfältig geplanten und kontinuierlich durchgeführten Techniktrainings zur Verbesserung der azyklischen Absprungbewegung vom Block ohne, dass die Entwicklung an-derer Leistungsvoraussetzungen beschränkt wird.

Start-stop systems are widely used in the car industry today but have not yet been fully implemented in the heavy-duty vehicle industry. The greater loads arising in the engines leads to excessive wear of the hydrodynamic bearings during starts and stops which has a distinct impact on the machine´s lifetime performance and reliability. This master thesis involves a comparative study of how different surface topographies of a shaft affects hydrodynamic bearing wear during start and stop conditions. The objective was to see if one can extend the bearing lifetime by doing minor changes to the shaft surface. This has been done by redesigning an existing start-stop test rig, increasing its operating system oil temperature to 90°C to provide a more accurate description of the bearing environment, to be able to conduct a series of start-stop cycling experiments. Upon examination of the experiment results, it becomes clear that a more polished surface of the shaft does reduce bearing wear significantly during starts and stops. It was also noticed that a more polished shaft surface does reach full-film lubrication at a lower rotational speed of the shaft, separating the shaft and the bearing surfaces. / Start-stoppsystem används idag i stor utsträckning inom bilindustrin men har ännu inte blivit implementerat fullt ut i den tunga fordonsindustrin. De större belastningarna som uppstår i motorn leder till överdrivet slitage på de hydrodynamiska glidlagren under start och stopp och har en tydlig inverkan på maskinens livslängd och pålitlighet. Detta examensarbete har innefattat en jämförande studie om hur olika axelytor påverkar nötningen av hydrodynamiska glidlager vid start och stoppförhållanden. Målet var att se ifall man kan lyckas förlänga lagrets livslängd genom att genomföra mindre förändringar av axelytan. Detta har utförts genom att omkonstruera en befintlig start-stopprigg, ökat oljesystemets driftstemperatur till 90°C för att ge en mer exakt beskrivning av den riktiga lagermiljön, för att sedan ha utfört en serie start och stopp experiment. Resultaten från experimenten visade tydligt att en mer polerad axelyta minskar lagerslitningen avsevärt under start och stopp. Det noterades också att en mer polerad axelyta ger fullfilmssörjning vid en lägre axelrotationshastighet, varvid axeln och lagerytorna separeras.

Jag har i denna uppsats studerat makroekonomiska faktorers påverkan på antal registrerade aktiebolag och enskilda näringsidkare i Sverige. Syftet har varit att bidra med variabler som ska kunna användas vid prognostisering av antal nyregistreringar av företag. Jag har valt ut de makroekonomiska faktorer som enligt tidigare forskning inom området, visat sig vara de vanligast förekommande. Studien har gjorts med multipel regressionsanalys med kontroll för multikollinearitet, autokorrelation och heteroskedasticitet. Resultatet tyder på att makroekonomiska faktorer som BNP, arbetslöshet och arbetslöshet inklusive fördröjd effekt samt inflation kan ha ett signifikant samband med antal registrerade aktiebolag. Analysen tyder även på att BNP har ett negativt samband med antal registrerade enskilda näringsidkare. Slutsatsen från detta är att det finns en skillnad mellan vad som påverkar antal registrerade aktiebolag och antal registrerade enskilda näringsidkare. Vidare studier behöver göras för att identifiera fler variabler som kan ha ett samband med antal nyregistreringar och då främst registreringar av enskilda näringsidkare. / This study investigates the influence of macroeconomic factors on the number of newly registered limited companies and sole traders in Sweden. The aim has been to contribute with variables that can be used in forecasting the number of new company registrations. I have chosen the macroeconomic factors which, according to previous research in this area, have proved to be the most common. The study has been done with multiple regression analysis and checked for multicollinearity, autocorrelation and heteroscedasticity. The result suggests that macroeconomic factors such as GDP, unemployment, unemployment including delayed effects and inflation can have a significant effect on the number of new registrations for limited companies. The analysis also suggests that GDP has a negative effect on the number of new sole traders. The conclusion of the study is that the factors affecting the number of new limited companies differ from those affecting the number of new sole traders. Further studies are needed in order to establish other variables that can influence the number of new registrations and in particular new registrations for sole traders. / <p>Betyg 170115</p>

No description available.

The goal of this thesis was to map historical progress of disarmament agreements between Russian Federation and The United States of America from the end of the World War II, through the Cold War and ending in the present, formulated by the latest agreement NEW START made in 2010. This period of time includes rounds of negotiations about SALT, SALT II, INF agreement, through START I, START II, which never came in effect, ending with NEW START. Thesis is analyzing agreements not only via itself agreement's lines or proposals but also with their negotiations that led to formation of the agreements including brief historical background in which they were formatted. Rather bigger attention in this thesis is dedicated to the NEW START agreement which gained experience from past agreements. Thesis is divided into 5 chapters where the first chapter is dealing with theoretical delimits of terms which are necessary for sufficient understanding of the textual mater of these agreements. Other chapters are designed so that after every short introduction of the historical background is following analysis of the agreements or their particular links and their comparison with the previous agreements. Last chapter is focused on the issues about controlling the fulfillments of the agreements under the agreements...

No description available.

No description available.