One of the greatest challenges of human today is to provide the continuous and sustainable energy supply to the worldwide society. This shall be done while minimizing all the negative consequences of the operation(s) to the environment and its living habitants including human beings, taking from the whole life cycle perspective. In this thesis work new solutions for treatment biomass and waste are analyzed.   Based on the fundamental research on the conversion of various materials (biomass: straw pellets, wood pellets; and waste: plastic waste, ASR residues after pyrolysis), converted by means of different systems (pyrolysis in a fluidized bed reactor, gasification in a fixed-bed reactor using highly preheated agents) it is recommended to classify materials against their charring properties under pyrolysis, in order to find the best destination for a given type of fuel.    Based on phenomenological research it was found that one of the important effects, affecting performance of downdraft gasifiers, is the pressure drop through the bed and grate. It affects, directly, the velocity profile, temperature distribution and of the height of the bed, especially for the grate with restricted passage surface, although it was not investigated in literature. The lower grate porosity, the higher conversion of fuel and heating value of gas is produced. However, the stability of the process is disturbed; therefore reducing the grate porosity below 20% is not recommended, unless the system is designed to overtake the consequences of the rising pressure inside the reactor. This work proposed the method for prediction of a total pressure drop through the fixed-bed downdraft gasifier equipped with a grate of certain porosity with an uncertainty of prediction ±7.10.     Three systems have been proposed; one for the treatment of automotive shredder residue (ASR), one for the treatment of plastic waste (polyolefins) and one for biomass (wood/straw pellets). Pyrolysis is an attractive mean of conversion of non-charring materials (like plastic waste) into valuable hydrocarbons feedstock. It gives directly 15-30% gaseous olefins while the residue consisting of naphtha-like feedstock has to be reformed/upgraded to olefins or other chemicals (e.g. gasoline generation) using available petrochemical technologies. Pyrolysis of complex waste mixture such as ASR is an attractive waste pretreatment method before applying any further treatments, whereby useful products are generated (gaseous and liquid fuel) and char, rich in precious metals. The solid residues are meant for further treatment for energy and metals recovery. Gasification is a complementary method for handling pyrolysis residues. However, metals can be removed before gasification. Pyrolysis of charring materials, like biomass, is a very important step in thermo-chemical conversion. However, the char being approximately 25%wt. contains still very high caloric value of about 30MJ/kg. This in connection with the High Temperature Steam Gasification process is a very promising technology for biomass treatment, especially, above 900oC. This enhances the heat transfer towards the sample and accelerates kinetics of the gasification. This, in turn, improves the conversion of carbon to gas, increases the yield of the producer gas and reduces tar content. At higher steam to fuel ratio the process increases the yield of hydrogen, making it suitable for second-generation biofuels synthesis, whereas at lower steam to fuel ratio (S/F&lt;2) the generated gas is of high calorific value making it suitable for power generation in a combined cycle. / <p>QC 20110607</p>

This thesis is about the design of the gating system and selection of proper alloy for defects free (grate bar) casting. The gating system plays an important role in casting manufacturing process. The gating system has different elements like pouring cup, sprue, well, runner, riser, and ingates. The function of the gating system is to provide molten metal to the mould cavity through different gating system elements.  Casting is a metal shaping process which is used to produce a cast component. The casting process depends upon the material, type of pattern, mould and various techniques like sand casting, investment casting, die casting, squeeze casting and lost foam casting. The sand mould casting process is used in this report. The casting process is used for making small to large cast parts, complicated shapes, and precision parts, etc. Making a casting without defects is an important requirement for its strength. The effective and efficient design of the gating system is necessary for making defects free castings. There are various defects like shrinkage cavity, porosity, pinholes, blowholes and incomplete filling that may occur in sand casting. The simulation software like Magma Soft and Nova Flow Solid are used to predict the possible defects in the casting. The uses of the simulation improve product quality and increase productivity. It also helps to reduce the rejection rate by identifying and controlling defects. This work is done at AB Bruzaholms Bruk as part of master thesis work at Jönköping University, Sweden. The company provides all the necessary data for simulation purposes. The design of the gating system is finalized as per company requirements and needs. The research questions that have been answered in this report based on the following points. 1) What does zero-defect mean? 2) Which is the best design among the ones that are prepared and simulated? 3) Which is the best alloy combination for casting parts that give defects free casting and better fluidity and filling?

No description available.

Gas turbines are widely used in industry for power generation and as a power source at "hard to reach" locations where other possibilities for electrical supply are insufficient. There is a strong need for greener energy, considering the effect that pollution has had on global warming, and we need to come up with ways of producing cleaner electricity. A way to achieve this is by increasing the combustion temperature in gas turbines. This increases the demand on the high temperature performance of the materials used e.g. superalloys in the turbine. These high combustion temperatures can lead to detrimental degradation of critical components. These components are commonly subjected to cyclic loading of different types e.g. combined with dwell-times and overloads at elevated temperatures, which influence the crack growth. Dwell-times have shown to accelerate crack growth and change the cracking behaviour in both Inconel 718 and Haynes 282. Overloads at the beginning of the dwell-time cycle have shown to retard the dwell time effect on crack growth in Inconel 718. To understand these effects more microstructural investigations are needed. The work presented in this licentiate thesis was conducted under the umbrella of the research program Turbo Power; "High temperature fatigue crack propagation in nickel-based superalloys", concentrating on fatigue crack growth mechanisms in superalloys during dwell-times, which have shown to have a devastating effect on the crack propagation behaviour. Mechanical testing was performed under operation-like conditions in order to achieve representative microstructures and material data for the subsequent microstructural work. The microstructures were microscopically investigated in a scanning electron microscope (SEM) using electron channeling contrast imaging (ECCI) as well as using light optical microscopy. The outcome of this work has shown that there is a significant increase in crack growth rate when dwell-times are introduced at the maximum load (0% overload) in the fatigue cycle. With the introduction of a dwell-time there is also a shift from transgranular to intergranular crack growth for both Inconel 718 and Haynes 282. When an overload is applied prior to the dwell-time, the crack growth rate decreases with increasing overload levels in Inconel 718. At high temperature crack growth in Inconel 718 took place as intergranular crack growth along grain boundaries due to oxidation and the creation of nanometric voids. Another observed growth mechanism was crack advance along phase boundaries with subsequent severe oxidation of the phase. This thesis comprises two parts. The first giving an introduction to the field of superalloys and the acting microstructural mechanisms that influence fatigue during dwell times. The second part consists of two appended papers, which report the work completed so far in the project.

The most common way of producing steel worldwide is with the continuous casting process, where a strand of steel is continuously cast. Further optimization of this process requires data from measurements, measurements which must take place in a hostile high-temperature and corrosive environment such as liquid steel. At Swerim, a Continuous Casting Simulator has been constructed to replicate the flow conditions in the process. A eutectic bismuth-tin alloy with properties similar to steel is used instead to make measurements in liquid metal possible. In this report pressure, velocity and vibration measurements were made using multiple sensors under different flow conditions.

In this work, the influence of different cooling rates (5, 20, 50 and 100 °C/s) on the microstructure and mechanical properties of Laser Metal Wire Deposited (LMwD) Ti-6Al-4V was investigated, this was done using a thermal-mechanical physical simulation system (Gleeble 3800, DSI). Two different soak times above β transus (held at 1100 °C), 5 and 40 s, were used and after cooling to 150 °C, the samples were tensile tested. The samples were characterized with optical microscopy (OM) and scanning electron microscopy (SEM) and hardness testing. The results were then compared, both with each other and with two reference samples, that were only heated to 150 °C and then tensile tested. It was found that for the lowest cooling rate, 5 °C/s, the microstructure had transformed from a basketweave α microstructure to a colony α microstructure in the center of the specimen waist where heating was most efficient. Ultimate tensile strength (UTS) was found to be in the range of 858 – 977 MPa, with the highest average being recorded for the reference samples, similar results were noted for the strain, with a range of  ⁓5 – 14 %, where the highest recorded average was for the reference samples. However, the extensometer used was not optimized for this kind of test, therefore percent reduction of area (RA) measurements were performed. The RA measurements produced a significantly different result than that obtained from the testing, a large scatter in the ductility was found, possibly due to thermal instability that occurred during testing. Overall, the microstructure appears to be relatively stable over the cooling range of 20 - 100 °C/s, no major differences were observed, the microstructure consisted of a homogeneous basketweave α microstructure, with little to no change in the measured average α lath thickness.

De ökande kraven på kvalité från kunder och ett allt strängare regelverk från myndigheter gällande miljön, har lett till att Ovako Sweden AB Hällefors har planer på att introducera polymer (Aquatensid) som nytt kylmedel i sin Induktionshärdningslinje. Detta för att minska risken för sprickbildning i materialet till följd av för stora spänningar, samtidigt som vattnet byts ut mot ett resultatmässigt bättre alternativ. Tidigare studier med lovande resultat har utförts inom området och detta arbete inriktar sig på att finna en balanserad koncentrationshalt av polymer i blandning med vatten som kan passa för hela Ovakos seghärdade sortiment.Tester har skett på två av de vanligaste stålsorterna (Ovako 356 och Ovako 495) dessa har gemensamt att de är relativt höglegerade stål i Ovakos sortiment. Stålsorterna har härdats i en kammarugn vid höga temperaturer och sedan kylts under omröring i ett bad av vattenblandad polymer vid varierande koncentrationer. Noggrann fysikalisk provning innefattande hårdhetsprofiler i Vickers, mikroskopering i ljusmikroskop och Svepelektronmikroskop (SEM). Detta för att se om eventuella skillnader i strukturen uppkommit, som kan ge tendenser till sprickuppkomst och försämrad härdbarhet. Resultaten av testerna visar att för stålsort 495B kan jämna hårdhetsintervall uppnås över de olika koncentrationerna, men att man får en större variation då man kyler 356D.

Metaller som bryts och utvinns primärt förekommer tillsammans med många andra metaller i malmer och mineral. Avfallsströmmar från metallindustrin har därför ett varierat innehåll av många olika metaller. Metallerna är ofta skadliga för miljön och kan skapa problem för metallproducenterna om halterna är så höga att avfallen inte ens kan deponeras. Det finns skräddarsydda metallurgiska processer för att upparbeta metallhaltigt avfall, i syfte att utvinna de värdefulla metallerna och producera en lakstabil slagg med lågt metallinnehåll. En lakstabil slagg kan ha miljömässiga fördelar som gör att den kan ersätta jungfruligt brutet material, exempelvis bergkross, som fyllnadsmaterial eller i andra anläggningsändamål. I detta projekt studerades två slagger som uppkommit genom behandling av metallhaltigt avfall. För båda slaggerna analyserades metallinnehåll och lakbarhet och resultaten jämfördes mot några valda bedömningsgrunder. Dels innehåller avfallsförordningen gränsvärden för det totala innehållet av metaller för att ett avfall ska betraktas som icke farligt, dels finns mottagnings-kriterier på deponier för avfall i olika farlighetsklasser. I mottagningskriterierna finns gränsvärden för koncentrationen av metaller i lakvätskan vid L/S-kvoten 0,1 l/kg samt den kumulativt utlakade mängden vid L/S-kvoten 10 l/kg. Lakbarheten testades med två olika metoder. På ackrediterat laboratorium gjordes ett standardiserat perkolationstest där materialet packas i en kolonn som sedan sakta genom-strömmas med vatten. Koncentrationen av olika ämnen mäts i lakvätskan när förutbestämda vattenvolymer passerat igenom och kan sedan räknas om till utlakad mängd. Det är endast resultat från ett sådant test som kan användas för att klassificera materialet enligt gällande deponeringskriterier. En billigare och enklare metod kan dock användas för jämförelse-provtagning. Det är ett tvåstegs skaktest där en uppvägd mängd material skakas med en bestämd vattenvolym. Fyra upprepade försök gjordes för varje slagg och lakvattnen sändes till laboratorium för analys. Koncentrationen i lakvätskan mättes och kunde räknas om till utlakad metallmängd. Vissa resultatskillnader mellan de båda metoderna noterades, men låga utlakade mängder uppmättes och materialen uppfyllde nästan alla mottagningskriterier för att kunna tas emot på deponier för inert avfall. Resultaten från kolonnlakningen visade på lägre utlakade mängder än resultaten från skakförsöken. Det kan förklaras med längre kontakttid mellan vatten och material i skakflaskorna. Där sker en nötning av materialet som frilägger nya lakbara ytor. I kolonnen är det hela tiden nytt vatten som kommer i kontakt med materialet. Fler tester bör göras för att bestämma totalhalten av metaller i slaggerna innan man beslutar att använda dem i någon tillämpning. Slaggerna bör inte nyttiggöras inom vattenskyddsområde eller annan plats där känsligt vatten riskerar att förorenas. / Primarily mined and extracted metals are in nature often found together with many other metals in ores and minerals. Therefore, waste from the metal industry might have a varied content of many different metals. These metals are often harmful to the environment and can cause problems. For the metal producers, there is a problem if the metal content in their waste is higher than what is accepted on landfills. There are accurate metallurgical processes to recover the valuable metals from the waste and produce a slag with a low metal content that also is leach stable. Such a leach stable slag might have environmental advantages though it could replace natural material such as gravel as a filler or in other construction purposes. In this project, two slags resulting from the treatment of metal-containing wastes has been studied. For both slags, the metal content and the leachability were analyzed and the results were compared against some selected criteria. The waste regulation declares limits for the total content of metals for which the waste can be considered non-hazardous. Also, there is acceptance criteria on landfills for waste in different hazard classes. The acceptance criteria describes limits for the concentration of metals in the leachate at L/S ratio of 0.1 l/kg, and the cumulative leached amount at L/S ratio of 10 l/kg. The leachability was studied with two different methods. At an accredited laboratory, a standardized percolation test was made. In such tests, material is packed in a column and then slowly perfused with water. The concentration of various substances is measured in the leachate when predetermined volumes of water has passed through the column and can then be converted into leached amount. It is only the results of such a test that can be used to classify material according to local landfill criteria. A cheaper and easier method which can be used for comparison testing is a two stage batch test. In these tests, a weighed amount of material is shaken with a given water volume for a given time. Four repeated attempts were made for each slag and the leachates was sent to the same laboratory for analysis. The concentration in the leachate were measured and could be counted on to leached metal variety. Some differences between the two methods was noticed, but low leached amounts were measured all over and the materials met almost all criteria in order to be accepted at landfills for inert waste. The results of the percolation test showed lower leached amounts than the results of the batch test. This can be explained by the longer contact time between the water and materials in the bottles. There, an abrasion of the material that uncovers new leachable surfaces occurs. In the column, there is always new water that comes in contact with the material. Extended testing should be done to determine the total content of metals in the slags before deciding to use them in any application. Slags should not be utilized in a water protection area or other place where there is a risk for contamination of any sensitive water.

No description available.

Nedbrytbara metaller utgör en ny klass av biomaterial med potential attersätta permanenta material i tillfälliga applikationer. Detta för att minskarisken för långvariga biverkningar. I den pågående forskningen för att utvecklanya nedbrytbara metaller är screening av nya material genom in vitro testmetoderett attraktivt alternativ för att undvika onödiga, tidskrävande ochdyrbara djurstudier.Denna avhandling fokuserar på in vitro-testning av zink- och magnesiumbaserademetaller. Inverkan av faktorer såsom sammansättningen av testlösningen,buffersystemet, belastning samt mikrostruktur hos legeringar undersöktes.Genom att använda elektrokemiska in situ tekniker såsom impedansspektroskopi(EIS) är det möjligt att studera gränssnittet mellan metall ochlösning och karakterisera egenskaperna hos den korroderande ytan. Ex situytkaraktäriseringstekniker som svepelektronmikroskopi och infraröd spektroskopianvändes sedan för att komplettera resultaten av de elektrokemiskamätningarna.Korrosionen av zink i Ringer’s lösning fanns vara närmare in vivo korrosionän korrosionen i fosfatbuffrad saltlösning (PBS). Ringers lösning är därför denföredragna testmiljön för långsiktig utvärdering av zinkbaserade metallerDet biologiska buffersystemet (CO2/H2CO3) bör företrädesvis användasför att stabilisera pH-värdet på testlösningen vid magnesiumnedbrytning. NärHEPES användes för att stabilisera pH ökade korrosionshastigheten på grundav bildning av mindre skyddande skikt av korrosionsproduktMöjligheten att använda helblod och plasma som mer kliniskt relevantatestmiljöer utvärderades och befanns producera reproducerbara resultat.Bildning av ett korrosionsskikt bestående av både organiskt och oorganisktmaterial detekterades på zink i både plasma och helblod.När zink prover i helbod utsattes för belastning förhindrade korrosionsskiktetbildningen av mikrosprickor och förtidigt brott av provet. Det varvidare möjligt att detektera tidig sprickbildning på grund av belastning avMagnesium AZ61-legering med EIS.Adsorption av organiska species på zinkytan under anodisk polariseringökar yttäckningen av Zn-joner i helblod. Den ökade yttäckningen leder sedantill utfällningen av ett skyddande skikt av zinkfosfater och en minskadkorrosionshastighet vid högre potentialer.Korrosion av Zn-Mg och Zn-Ag legeringar i Ringers lösning befanns skevia selektiv upplösning. Lokal utfällning av korrosionsprodukter och bildningav ett poröst, mindre skyddande skikt av korrosionsprodukter hittades påZn-Mg legeringar. Den selektiva upplösningen av Zn-Ag legering orsakade enanrikning av AgZn3 vilket kan påverka biokompatibiliteten av ett implantatmed tiden. / Degradable metallic implants are a new class of biomaterials with potentialto replace permanent materials in temporary applications to reduce therisk of long term adverse effects.This thesis focuses on in vitro testing of zinc and magnesium based metals.As new degradable metals are developed screening of new materials within vitro test methods is an attractive option to avoid unnecessary, time consumingand expensive animal studies. The influence of factors such as ioniccomposition of the test solution, buffer system, strain and alloy compositionwas investigated. By employing electrochemical in situ techniques such asimpedance spectroscopy it is possible to study the metal-solution interfaceand determine the properties of the corroding surface. Ex situ surface characterizationtechniques such as scanning electron microscopy and infraredspectroscopy were then used to complement the results of the electrochemicalmeasurements.The importance of appropriate selection of the test solution is highlightedin this work. Zinc was found to corrode in Ringer’s solution by a mechanismcloser to in vivo corrosion than in a phosphate buffered saline solution(PBS).Ringer’s solution is therefore the more appropriate test environment for longterm evaluation of zinc based metals.When evaluating the corrosion of Zn-Mg and Zn-Ag alloys in Ringer’ssolution selective dissolution was found to occur for both types of alloys. Localprecipitation and formation of a porous, less protective, layer of corrosionproducts was found for Zn-Mg alloys. The selective dissolution of Zn-Agalloy caused an enrichment of AgZn3 on the surface which may affect thebiocompatibility of the alloy.The use of HEPES to maintain the pH of the test solution increasedthe corrosion rate of magnesium due to formation of a less protective layerof corrosion products. Magnesium corrosion should therefore preferably bestudied in solutions where the pH is maintained by the biological buffer systemCO2/H2CO3.In addition to saline solutions human whole blood and plasma were evaluatedas more clinically relevant in vitro environments. They were found toproduce reproducible results and to be suitable for short term experiments.Formation of a corrosion product layer comprised of both organic and inorganicmaterial was detected on zinc in both plasma and whole blood.During anodic polarization the adsorption of organic species on the zincsurface was found to increase the surface coverage of Zn ions in whole blood.The increased surface coverage then allowed for precipitation of a protectivelayer of Zn5(PO4)3 and a subsequent decrease in corrosion rate at higherpotentials.When subjecting zinc samples to strain the organic/inorganic corrosionproduct formed in whole blood was observed by impedance spectroscopy toprevent micro cracking and premature failure.The cracking of magnesium alloy samples under applied strain was alsocharacterized by impedance. Changes in surface properties due to crack initiation / <p>QC 20171019</p>