Volvo Aero utvecklar, konstruerar, tillverkar och utför underhåll av motorer och tillhörande komponenter för civila och militära flygplan. Visionen är att leverera världsledande transportlösningar genom ständig förbättring och långsiktig utveckling av verksamheten, vilket för det dagliga arbetet innebär systematisk problemlösning genom metodiken praktisk problemlösning, vars ursprung är Toyota. Syftet med studien var att undersöka huruvida Volvo Aeros tillämpning av praktisk problemlösning var enkel, systematisk och vägledande, vilket ur Toyotas perspektiv ger förutsättning för effektiv problemlösning. Inledningsvis beskrevs Toyotas inställning och beteende till problemlösning utifrån The Toyota Way, som sedan följdes upp med en litteraturstudie gällande praktisk problemlösning. Vidare genomfördes en pilotstudie där Volvo Aeros tillämpning av praktisk problemlösning applicerades på ett organisatoriskt problem. Därefter utvärderades pilotstudien och förbättringsområden identifierades där metodiken var svår, otydlig och otillräckligt vägledande. Slutligen föreslogs följande förbättringar gällande Volvo Aeros tillämpning av praktisk problemlösning, vilka var vetenskapligt förankrade till Toyota. Definiering och analysering av symtomen ger förståelse för problemets orsaker. Kvantifiering av nuvarande tillstånd och det förväntades åskådliggör problemets omfattning. Framgår grundorsaken tydligt är sannolikt motåtgärden uppenbar. En god tillämpning av Plan-Do-Check-Act (PDCA) utgör ett effektivt och kraftfullt maskineri för ständig förbättring. Förbättringarna som föreslogs syftade till att förenkla Volvo Aeros metodik och ge användaren ökad trygghet och vägledning, vilket ger förutsättning för effektiv problemlösning som möjliggör daglig tillämpning och främjar ständig förbättring. / Volvo Aero develops, designs, manufactures and performs maintenance of engine and related components for civil and military aircrafts. The vision is to deliver world-leading transport solutions through continuous improvement and long term business deployment, which for the daily work means systematic problem solving through the methodology practical problem solving, whose origin is Toyota. The purpose of this thesis was to examine whether Volvo Aero’s approach of practical problem solving was simple, systematic and guided, which from Toyota’s point of view creates sound conditions for effective problem solving. Initially, Toyota’s attitude and behaviour towards problem solving was described from the point of view of The Toyota Way. Thereafter, a literature study on practical problem solving was completed. Furthermore, a pilot study was carried out where Volvo Aero’s approach to practical problem solving was applied to an organisational problem. The pilot study was evaluated and areas for improvements were identified where the methodology was difficult, indistinct and inadequate guided. Finally, improvements were proposed regarding Volvo Aero’s approach to practical problem solving, which was scientifically anchored to Toyota. Defining and analysing the symptoms brings understanding for the causes of the problem Quantifying the present condition and the expected illustrates the magnitude of the problem Appears the root cause to be clear is probably the countermeasure obvious A considerable approach using Plan-Do-Check-Act (PDCA) provides an effective and strong tool for continuous improvement The improvements were proposed with purpose to simplify Volvo Aero’s methodology and to support and guide the user, which creates sound conditions for effective problem solving and provides opportunities for daily use that foster continuous improvement.

Uppgiften som låg till grund för denna uppsats, var att ge förslag på produktivitetshöjande åtgärder på Electrolux Distriparts godsmottagning. Vår avsikt var att tillämpa delar av Toyotas produktionssystem på den befintliga processen. Detta resulterade i en serie förslag som, om de tillämpas, drastiskt kommer höja produktiviteten i den aktuella processen. / The task, which is the basis of this report, was to suggest some productivity-raising actions for the incoming goods departments at Electrolux Distriparts. The project set out to utilise parts of the Toyota production model in the existing process. This resulted in a series of suggestions, which if implemented, would drastically increase the productivity of the relevant process.

<p>Uppgiften som låg till grund för denna uppsats, var att ge förslag på produktivitetshöjande åtgärder på Electrolux Distriparts godsmottagning. Vår avsikt var att tillämpa delar av Toyotas produktionssystem på den befintliga processen. Detta resulterade i en serie förslag som, om de tillämpas, drastiskt kommer höja produktiviteten i den aktuella processen.</p> / <p>The task, which is the basis of this report, was to suggest some productivity-raising actions for the incoming goods departments at Electrolux Distriparts. The project set out to utilise parts of the Toyota production model in the existing process. This resulted in a series of suggestions, which if implemented, would drastically increase the productivity of the relevant process.</p>

Embalagens de plástico expandido são utilizados como embalagens de alimentos, entre eles o poliestireno expandido (EPS). Suas principais características são a leveza e sua não biodegradabilidade. Estas embalagens geralmente são descartadas logo após o uso e geram grandes quantidades de resíduos. Espumas feitas a base de amido termoplástico (TPS) podem substituir o EPS nestes casos, pois são feitas a partir de fontes renováveis e são materiais biodegradáveis. Entretanto, embalagens de espuma TPS possuem grande afinidade pela água e isso consequentemente afeta seu uso. Uma forma de resolver este problema é recobrir estas espumas TPS com um material mais hidrofóbico, dificultando o contato da água com o amido. Nesse sentido, o objetivo deste trabalho foi desenvolver espumas de TPS de diferentes amidos e revesti-las com quitosana e poliácido láctico (PLA), pois também são materiais biodegradáveis e são menos hidrofílicos do que o amido. Três fontes de amido (batata, mandioca e milho) foram analisadas conjuntamente para produzir espumas TPS com propriedades mais desejáveis para embalagens. As espumas foram produzidas a partir de amido, glicerol e água nas proporções mássicas de 62/5/33, respectivamente. Dentre os tipos de amido escolhidos, a espuma TPS de milho mostrou ser mais densa e rígida, apresentando maior densidade e maior módulo elástico (0,20 g/cm3 e 106 MPa, respectivamente) em comparação com espumas TPS de batata (0,11 g/cm3 e 39 MPa) e mandioca (0,10 g/cm3 e 39 MPa). A espuma TPS de batata apresentou maior flexibilidade e resistência ao impacto, e devido a estas vantagens é a mais adequada ao uso em embalagens. Os recobrimentos de quitosana e PLA diminuíram a absorção de água da espuma TPS. Enquanto que a espuma sem recobrimento absorveu aproximadamente 280% do seu peso em água, espumas TPS com 6% m/v de quitosana absorveram 100% e espumas TPS com 6% m/v de PLA absorveram 50% em média. O PLA mostrou ser a melhor opção de recobrimento para as espumas pois apresentou os menores valores de absorção de água e aumentou as propriedades mecânicas da espuma. / The expanded polystyrene (EPS) is used in a variety of food packaging, mainly in packages whose characteristics is the single use. These packages are usually discarded soon and generate large amounts of waste. Thermoplastic starch (TPS) foams can replace the EPS in these cases, because it comes from renewable and biodegradable sources. However, starch packaging has great affinity for water and it affects its use. One way to solve this problem is to cover the TPS foam with a more hydrophobic material, hindering the contact of water with starch. In this work, chitosan and polylactic acid (PLA) were used as coatings, as they are also biodegradable materials and are more hydrophobic than starch. Three sources of starch (potato, cassava and corn) were analyzed conjointly to produce TPS foams with more desirable properties for packaging. The foams were made from starch, glycerol and water in the proportion of 62/5/33 (% m/m) respectively. Among the starch types used, corn TPS foam presented higher density and higher stiffness (0,20 g/cm3 and 106 MPa, respectively) compared to potato (0,11 g/cm3 and 39 MPa) and cassava (0,10 g/cm3 e 39 MPa) TPS foams. The potato TPS foam showed greater flexibility and impact resistance, and due to these advantages is the most suitable for use in packaging. The chitosan and PLA coatings decreased the water absorption of the TPS foam. While the uncoated TPS foam absorbed approximately 280% of its weight in water, TPS foams with 6% w/v chitosan absorbed 100% and TPS foams with 6% m / v PLA absorbed 50% on average. The PLA was found to be the best option for coating the TPS foams because presented the lowest water absorption values and increased the mechanical properties of the foams.

La conversion photovoltaïque présente de nombreux avantages. Actuellement, les technologiesbasées sur l’élaboration de wafers de silicium cristallins dominent le marché, mais sont responsablesde pertes de matières importantes, très néfastes au coût de production des cellules. Le défi à releverest donc la réalisation de matériaux bas coûts en silicium par un procédé de métallurgie des poudres.Cependant, le frittage du silicium est dominé par des mécanismes de grossissement de grains quirendent la densification difficile par frittage naturel. Dans la littérature, l’identification de cesmécanismes est sujette à controverse. En particulier, le rôle de la couche d’oxyde natif (SiO2) à lasurface des particules de silicium reste inexploré. Dans ce manuscrit, l’influence de l’atmosphère surla réduction de cette couche de silice au cours du frittage est étudiée par analysethermogravimétrique. Les cinétiques de réduction sont en accord avec un modèle thermochimiqueprenant en compte, les quantités d’oxygène initialement présentes dans poudre, la pression partielleen espèces oxydantes autour de l’échantillon et l’évolution de la porosité du fritté. Pour la premièrefois, des données expérimentales permettent de montrer que la couche de silice inhibe legrossissement de grain. Des nouveaux procédés, basés sur un contrôle de l’atmosphère enmonoxyde de silicium (SiO(g)) autour de l’échantillon, sont alors proposés afin de maitriser la stabilitéde cette couche. Bien que la couche d’oxyde retarde les cinétiques de diffusion en volume, sonmaintien à des températures de 1300 – 1400 °C permet d’améliorer significativement la densification.Dans ces conditions, le comportement au frittage du silicium peut être séparé en deux étapes,clairement mises en évidences par la présence de deux pics de retrait sur les courbes de dilatométrie.Ce résultat est inhabituel compte tenu de l’aspect monophasé du matériau étudié. Cependant, il peutêtre expliqué à l’aide d’un modèle cinétique de frittage, basé sur des simplifications géométriques enaccord avec l’évolution microstructurale du matériau. / Photovoltaic conversion is a promising energy resource. Bulk crystalline silicon technologies currentlydominate the market but suffer from high material losses that are highly detrimental to solar cellproduction costs. The challenge is then the elaboration of low cost silicon materials through a powdermetallurgy route. However, silicon sintering is dominated by grain coarsening mechanisms thatpreclude densification. Identification of these mechanisms is controversial in the literature. Especially,the role of the native oxide layer (SiO2) at the powder particle surfaces has remained unexplored yet.In this manuscript, the influence of the atmosphere on the reduction of this silica layer is studied usingthermogravimetric analysis. Reduction kinetics is consistent with a thermochemical model taking intoaccount the powder oxygen content, the partial pressure of oxidizing species and the pore morphologyof the sintered material. For the first time, experimental evidences support the idea that the silica layerinhibits grain coarsening. New sintering processes, involving a control of the silicon monoxideatmosphere (SiO(g)) surrounding the sample are then proposed and investigated in order to monitorthe stability of this layer. Stabilization of the silica layer at temperatures as high as 1300 – 1400 °C isshown to enhance densification although it retards lattice diffusion kinetics. In these conditions, thesintering behavior can be divided into two sequential stages marked by two shrinkage peaks on thedilatometric curves. This result is unusual for the sintering of single-phase materials. However, it canbe explained with help of a kinetic model using appropriate geometrical simplifications andobservations of the sample microstructures.

Embalagens de plástico expandido são utilizados como embalagens de alimentos, entre eles o poliestireno expandido (EPS). Suas principais características são a leveza e sua não biodegradabilidade. Estas embalagens geralmente são descartadas logo após o uso e geram grandes quantidades de resíduos. Espumas feitas a base de amido termoplástico (TPS) podem substituir o EPS nestes casos, pois são feitas a partir de fontes renováveis e são materiais biodegradáveis. Entretanto, embalagens de espuma TPS possuem grande afinidade pela água e isso consequentemente afeta seu uso. Uma forma de resolver este problema é recobrir estas espumas TPS com um material mais hidrofóbico, dificultando o contato da água com o amido. Nesse sentido, o objetivo deste trabalho foi desenvolver espumas de TPS de diferentes amidos e revesti-las com quitosana e poliácido láctico (PLA), pois também são materiais biodegradáveis e são menos hidrofílicos do que o amido. Três fontes de amido (batata, mandioca e milho) foram analisadas conjuntamente para produzir espumas TPS com propriedades mais desejáveis para embalagens. As espumas foram produzidas a partir de amido, glicerol e água nas proporções mássicas de 62/5/33, respectivamente. Dentre os tipos de amido escolhidos, a espuma TPS de milho mostrou ser mais densa e rígida, apresentando maior densidade e maior módulo elástico (0,20 g/cm3 e 106 MPa, respectivamente) em comparação com espumas TPS de batata (0,11 g/cm3 e 39 MPa) e mandioca (0,10 g/cm3 e 39 MPa). A espuma TPS de batata apresentou maior flexibilidade e resistência ao impacto, e devido a estas vantagens é a mais adequada ao uso em embalagens. Os recobrimentos de quitosana e PLA diminuíram a absorção de água da espuma TPS. Enquanto que a espuma sem recobrimento absorveu aproximadamente 280% do seu peso em água, espumas TPS com 6% m/v de quitosana absorveram 100% e espumas TPS com 6% m/v de PLA absorveram 50% em média. O PLA mostrou ser a melhor opção de recobrimento para as espumas pois apresentou os menores valores de absorção de água e aumentou as propriedades mecânicas da espuma. / The expanded polystyrene (EPS) is used in a variety of food packaging, mainly in packages whose characteristics is the single use. These packages are usually discarded soon and generate large amounts of waste. Thermoplastic starch (TPS) foams can replace the EPS in these cases, because it comes from renewable and biodegradable sources. However, starch packaging has great affinity for water and it affects its use. One way to solve this problem is to cover the TPS foam with a more hydrophobic material, hindering the contact of water with starch. In this work, chitosan and polylactic acid (PLA) were used as coatings, as they are also biodegradable materials and are more hydrophobic than starch. Three sources of starch (potato, cassava and corn) were analyzed conjointly to produce TPS foams with more desirable properties for packaging. The foams were made from starch, glycerol and water in the proportion of 62/5/33 (% m/m) respectively. Among the starch types used, corn TPS foam presented higher density and higher stiffness (0,20 g/cm3 and 106 MPa, respectively) compared to potato (0,11 g/cm3 and 39 MPa) and cassava (0,10 g/cm3 e 39 MPa) TPS foams. The potato TPS foam showed greater flexibility and impact resistance, and due to these advantages is the most suitable for use in packaging. The chitosan and PLA coatings decreased the water absorption of the TPS foam. While the uncoated TPS foam absorbed approximately 280% of its weight in water, TPS foams with 6% w/v chitosan absorbed 100% and TPS foams with 6% m / v PLA absorbed 50% on average. The PLA was found to be the best option for coating the TPS foams because presented the lowest water absorption values and increased the mechanical properties of the foams.

Söderberg electrodes take part in the production of ferroalloys, copper, nickel, platinum, and calcium carbide. They are involved in a continuous and with low costs operation. The study of such electrodes is essential, since research and new findings will provide us with vital information regarding the operation of such furnaces leading to a more efficient production. Therefore, the study of Söderberg electrodes materials characteristics is of great importance. The current work refers to the thermal properties of Söderberg electrode paste by focusing on the thermal conductivity coefficient from room temperature up to 800 °C with the Transient Plane Source (TPS) method applied to an electrode paste material with softening point at 65°C. Another electrode paste with higher softening point at 90 °C and an already baked material are studied to some extent. The study gives significant results for the thermal conductivity coefficient for all the investigated cases. Results indicate variation of coefficients regarding the phase evolved during heating at different temperatures. In principle, thermal conductivity of the green paste with low softening point decreases until 400°C and increases after the baking point which is found in between 400-500°C. A few measurements for the green paste with higher softening point indicate the same trend. For the case of the fully baked electrode, thermal conductivity seems to keep an increasing trend according to temperature increase. On the two last mentioned materials, more experimental work will be conducted in future. / Söderberg-elektroder används till produktionen av ferrolegeringar, koppar, nickel, platina och kalciumkarbider. De är involverade i kontinuerliga och lågkostnadsoperationer. Studien av sådana elektroder är väsentlig eftersom forskning och nya fynd kommer att ge oss viktig information om driften av sådana ugnar vilket leder till en effektivare produktion. Därför är studien av Söderberg-elektrodens materialegenskaper av stor betydelse. Det nuvarande arbetet refererar till de termiska egenskaperna hos Söderberg-elektrodpastan genom att fokusera på den termiska konduktivitetskoefficienten från rumstemperatur upp till 800°C med den TPS-metoden (Transient Plane Source) tillämpad på ett elektrodpasta-material med en mjukningspunkt vid 65°C. En annan elektrodpasta med en högre mjukningspunkt vid 90°C samt ett redan bakat material studeras även till viss del. Studien ger signifikanta resultat för värmeledningsförmågan för alla undersökta fall. Resultaten indikerar på variationer av koefficienterna gällande fasen som utvecklas under uppvärmning vid olika temperaturer. I stort sett minskar värmeledningsförmågan hos den gröna pastan med låg mjukningspunkt upp till 400°C och ökar efter bakningspunkten som finns mellan 400-500°C. Några mätningar för den gröna pastan med en högre mjukningspunkt visar samma trend. När det gäller den helt bakade elektroden verkar värmdeledningsförmågan hålla en ökande trend beroende på temeperaturökningen. På de två sistnämnda materialen kommer mer experimentellt arbete att genomföras i framtiden.

International Telemetering Conference Proceedings / November 04-07, 1991 / Riviera Hotel and Convention Center, Las Vegas, Nevada / As we develop more space vehicles, a pressing requirement emerges to provide precision tracking information. This need for exact time and space-position information (TSPI) persists whether developing and testing space weapons or locating the precise position of intelligence-gathering satellites. Because this is a worldwide tracking requirement, the use of conventional tracking techniques such as radar is precluded. Fortunately the Global Positioning System (GPS) is now in place and can provide the tracking information required. GPS offers two techniques for tracking space vehicles. A GPS receiver can be installed on the vehicle to determine the position that is then relayed to a ground terminal, or a GPS frequency translator can be used to compute the vehicle position at the master groundsite. Since both techniques have been proven satisfactory, the specific tracking requirement determines the method selected. For the flight tests of the Exoatmospheric Reentry-Vehicle Interceptor Subsystem (ERIS), the GPS frequency translator technique is used. A GPS frequency translator is installed on the target (a reentry-vehicle launched on a Minuteman from Vandenberg), and a translator is also installed on the ERIS, which is launched from Meck Island in the Kwajalein Atoll. The GPS frequency translator approach was chosen for these tests for a variety of reasons, the most important of which were the limited instrumentation space on the target and interceptor, the extreme dynamics of the interceptor, the tracking accuracy required, and the range at which the operation must be tracked. For the tracking of orbiting satellites, a GPS receiver can be flown on the satellite with its derived position information continuously stored. This data can then be dumped as the satellite passes over a selected groundsite.

Présentation de travaux sur la création d'environnements collaboratifs synchrones réutilisables pour télé-TPs.

Condition based monitoring of Thermal Protection Systems (TPS) is necessary for safe operations of space shuttles. In the current research Terahertz radiation (T-ray) has been used to detect mechanical and heat induced damages in TPS tiles. Voids and cracks inside the foam tile are denoted as mechanical damage while property changes due to long and short term exposures of tiles to high heat are denoted as heat induced damage.Ultrasonic waves cannot detect cracks and voids inside the tile because the tile material (silica foam) has high attenuation for ultrasonic energy. Instead, electromagnetic terahertz radiation can easily penetrate into the foam material and detect the internal voids although this electromagnetic radiation finds it difficult to detect delaminations between the foam tile and the substrate plate. Thus these two technologies are complementary to each other for TPS inspection.Ultrasonic and T-ray field modeling in free and mounted tiles with different types of mechanical and thermal damages has been the focus of this research. Shortcomings and limitations of FEM method in modeling 3D problems especially at high-frequencies has been discussed and a newly developed semi-analytical technique called Distributed Point Source Method (DPSM) has been used for this purpose.A FORTRAN code called DPSM3D has been developed to model both ultrasonic and electromagnetic problems using the conventional DPSM method. DPSM has been extended from ultrasonic applications to electromagnetic to model THz Gaussian beams, multilayered dielectrics and Gaussian beam-scatterer interaction problems. Since the conventional DPSM has some drawbacks, to overcome it two modification methods called G-DPSM and ESM have been proposed.The conventional DPSM in the past was only capable of solving time harmonic (frequency domain) problems. In this research DPSM has been extended to model DPSM transient problems. This modified technique has been denoted as t-DPSM.Using DPSM, scattering of focused ultrasonic fields by single and multiple cavities in fluid&solid media is studied. A comparison between the radiation forces generated by the ultrasonic energies reflected from two small cavities versus a single big cavity is also carried out.