The problem of this study was to compare the effectiveness of the note-test method and the traditional lecture method of teaching general introductory microbiology. The study was prompted by the desire to improve teaching strategies in microbiology in order to improve the attitudes of students taking microbiology at the Indiana College of Mortuary Science. The conclusions are that the note-test method of teaching is at least as effective as the traditional lecture method but is not better than the traditional method in regard to student achievement or student attitudes about the microbiology course to which they were assigned. Since the method requires less lecturing than the traditional lecture method used in this study, it may be used effectively by some instructors in certain subject matter areas and may hold promise in maintaining achievement and acceptable attitude levels.

Content: A characteristic of leather is that if it is gradually heated in aqueous solution it reaches a temperature where sudden and irreversible shrinkage occurs. This phenomenon is related to the denaturalization of the collagen protein that conforms the hide and is known as leather shrinkage. Specifically, the internal bonds break thus causing a shortening of the skin that can be up to a 35% from its original length. Accordingly, one of the most used methods to check the quality of the leather tanning process is the determination of the contraction temperature according to the ISO 3380:2015 standard. This method measures the leather shrinkage when constantly increasing the sample temperature. The shrinkage temperature corresponds to the temperature when the sample suddenly contracts. The value of this temperature indicates the degree of collagen stability and therefore, when higher, the leather will have better quality and resistance. The process of leather shrinkage can be divided in different stages. Several authors discriminate temperature A1 (when the first fibre starts to shrinkage), temperature C (when there is a massive shrinkage) and finally temperature A2 (when the last fibres are contracted individually). The method that describes the ISO 3380:2015 standard uses a device where the determination of the shrinkage temperature is performed visually by the laboratory technician. Consequently, the method tends to be imprecise and subjective. It should also be noticed that the device proposed by the standard does not allow differentiation between the different stages of the contraction process. There are other methods to determine leather shrinkage temperature including differential scanning calorimetry, microscopic hot table, thermogravimetric analysis, differential thermal analysis and thermomechanical analysis. All these methods involve complex devices and are only suitable for specialized personnel. In this work, a new device is developed to precisely measure the leather shrinkage temperature and to distinguish the different contraction stages. In addition, the proposed device is simple, easy to use and inexpensive, which facilitates its use in any industry. The developed system consists basically of a load cell to measure the strength produced by the shrinkage of the leather. With the logged data during the test a strength versus temperature graph is built. By means of its interpretation, the different stages of shrinkage can be determined. Different mathematical analysis of the logged data is proposed to determine the shrinkage stages temperatures, thus achieving a high degree of certainty and repeatability. Take-Away: A new device, simple and inexpensive, is developed to precisely measure the leather shrinkage temperature and to distinguish the different contraction stages.

This master´s thesis deals with bismuth low temperature solder pastes. Describes the properties of bismuth solder pastes. It shows the process of manufacturing a printed circuit board for test. The thesis also characterizes laboratory temperature profile setting for the BiSn soldering pastes. Solder paste printing and placement 0 ohm rezistors to printed circuit boards with different surface finishes in the manufacturing plant. Setting of solder profiles for low soldering pastes in reflow oven. Testing resistence of mounted zero resistor on the test board at different aging temperature were analysed. Resistance measurement after a specified time. Testing of solder joint strenght of printed circuit boards for different surface treatments. Changes in structure wereanalysed on microsections for solder pastes.

The aim of the diploma thesis is to clarify the topic of calibration samples used in eddy current testing on equipment in nuclear energy. The theoretical part of the diploma thesis is focused on the eddy current testing method, which belongs to the technology of non-destructive defectoscopy. This part of the work describes the principle of the method, its scope, limitations and dividing of sensors used in this test method. The work briefly describes the physical principle of the laser, its types and operating modes. The practical part of the work is focused on the production of a calibration samples by laser. Another point of the work is the comparison of data obtained from eddy current measurements on samples made by laser and on calibration samples used in practice.

Detta examensarbete har genomförts på uppdrag av CBI Betonginstitutet. Handledare till examensarbetet har varit professor Johan Silfwerbrand från CBI och examinator Per Roald från Kungliga Tekniska Högskolan i Haninge.  Idag är betong ett byggmaterial som används i stor omfattning tack vare sin beständighet, miljövänlighet och lönsamhet. Betong hittar man i både gamla och nyproducerade konstruktioner. Även med bra egenskaper kan betong vara ofullkomlig när den prepareras på fel sätt.  För att underlätta gjutning och arbetbarhet av betong användes förut i många fall mycket vatten och detta resulterade i att beständigheten på betong försämrades. De flesta gamla betongkonstruktionerna är nu i stort behov av renovering. Det synliga beviset kan vara spricknärvaro på ytan och detta kan ha följd att vatten tränger in och orsakar bland annat frost- och saltangrepp samt korrosion i armering. Betong som är skadad eller sliten kan behöva renoveras genom att avverkas delvis eller helt. För att hitta en lämplig avverkningsmetod och reparationsmaterial behöver man först ta reda på skadorna, ställa krav på lagningen, tänka på hur lagningen kommer att utföras och hur upprepningen av skadan ska förebyggas. För att reparera den skadade betongen, avverkas den först och sedan gjuts pågjutningar på den friska och kvarstående delen. Pågjutningar används även i flerskiktsgolv t ex gjuts pågjutningar på prefabricerade bjälklag i olika köpcentrum. Det finns flera typer av bilningsmetoder och de påverkar den kvarstående betongen på olika sätt. De mest använda metoder är vattenbilning och hydraulisk bilning. Vattenbilning är den mest använda inom anläggningssektorn och den effektivaste och lönsammaste metoden. Betongen bilas bort med högtrycksvatten och lämnar en grov och skonsam yta på den friska betongen. Hydraulisk bilning är den äldsta, billigaste och enklaste metoden men nackdelen är att den orsakar mikrosprickor i den friska betongen. Efter betongbilningen måste man se till att man har förutsättningar för en god vidhäftning mellan gammal och pågjuten betong. Vidhäftning är beroende av ett antal faktorer och de fem viktigaste av dem är renhet, mikrosprickfrihet, frånvaro av cementhud, god kompaktering och god härdning.  I första delen av examensarbetet testas en provningsmetod som mäter hur ren en motgjutningsyta är. I detta fall används en vit mikrofiberduk som krontrollmätare på renhet. Olika varianter av smuts applicerades på ytan av en betongplatta för att testa mikrofiberdukens uppsugningsförmåga. Mikrofiberduken S-sveptes över den smutsiga betong ytan och redan där sågs det tydligt hur bra mikrofiberduken är på att absorbera smuts. På samma sätt utfördes det på en ren yta och den använda duken förblev vit vilket är ett tydligt bevis på att ytan på betongplatta är helt ren och redo för pågjutning.  Examensarbetets andra del tar upp en jämförelse mellan vidhäftningen på en ren pågjuten motgjutningsyta och en oren motgjutningsyta. Vi studerade renhetens inverkan på vidhäftningen mellan gammal och pågjuten betong och som avverkningsmetod användes vattenbilning. För att utföra det, har två betongplattor gjutits och sedan vattenbilats. Den bilade ytan på både plattorna delades i olika delar, där olika varianter av smuts applicerades på halva betongplattan och andra halvan var den rena referensen. Efter detta göts ny, pågjuten betong på båda betongplattorna. Fyra veckor senare togs dragtester för att se om draghållfasthet försämras i över-, underbetong eller i fogen på grund av orenhet jämfört med referensen.  Renhet har en stor påverkan på vidhäftningen mellan gammal och ny, pågjuten betong. Draghållfastheten försämras om motgjutningsytan inte är helt ren. Beviset är ett brott i fogen mellan betongskikten, med en väldig liten dragkraft och det syns tydligt att smuts som olja eller träflis precis i fogen när borrcylinder dras ut. För att lösa problemet rekommenderas att använda en vit mirakel duk för att vara säker att motgjutningsytan är helt ren innan pågjutningar gjuts på och detta bevisas med en oförändrad vit färg på duken. / This Bachelor’s thesis project has been commissioned by Swedish Cement and Concrete Research Institute. Our supervisor for this thesis project has been Prof. Johan Silfwerbrand and examiner Per Roald from The Royal Institute of Technology in Stockholm. Nowadays, concrete is a building material that is widely used because of its durability, environmental friendliness and profitability. Concrete can be found in both old and new designs produced. Even with good performance concrete can be imperfect when it is prepared incorrectly. To facilitate the handling of concrete plenty of water was often used before and this resulted in concrete deterioration. Many old concrete structures are now in great need of renovation. The visible proof can be the presence of micro cracking on the surface and this may be due to the ingress of water in the concrete and causes including freezing and salt attack and corrosion of the reinforcement.   Concrete that is damaged or worn may need to be removed partly or completely. Appropriate removal methods and repair materials are needed, the causes of damage has to be determined, establishing of requirements for repair of concrete, the process of repairing has to be settled and the prevention of the repetition of the damage has to be determined. The damaged concrete has to be removed and be replaced by new overlay concrete. The overlay concrete is used as well in multi-layer floor, for example in various shopping centers overlay concrete is placed on precast slabs. There are several methods of concrete removal and they have different impact on the surface of the remaining concrete. The most widely used methods are the water jet and the hydraulic jetting. Water jet or hydro demolition is the most widely used in civil engineering sector and an efficient and profitable method. The concrete is removed by high pressure water that leaves a rough and gentle surface of the remaining concrete. Hydraulic jetting is the oldest, most common method and easiest concrete removal method. The negative impact of this method is that it causes micro cracks on the remaining concrete.  After the concrete has been removed there is a need to ensure that the conditions of getting a good bond between the old concrete and the overlay concrete are there. A good bond is dependent on a number of factors, and five of them are most important: micro cracks absence, the absence of laitance layer, cleanliness, high compaction and good curing.   In the first part of the thesis it is tested a test method that measures how clean the surface, there the overlay concrete will be placed, is. In this case, a white microfiber cloth is used as the crown control measure of cleanliness. Different types of dust and contaminations are applied to the surface of a concrete slab to test the cloth’s capacity to absorb the contaminations. The microfiber cloth is swept with S-pattern onto the contaminated concrete surface and already there it was obvious how good microfiber cloth is at absorbing dirt. In the same way this process was performed on a clean surface and the cloth remained white which is a clear proof that the surface of the concrete slab is perfectly clean and ready for casting.  The second part of this thesis deals with a comparison between the adhesion to a clean surface and unclean one. We study the effect of cleanliness on the bond between old concrete and a new-cast concrete overlay with water jet as a removal of the old concrete. To perform it, two concrete slabs were cast and then water jetted. The jetted surfaces of both slabs were divided into different zones, in which different varieties of contaminations were applied to half of the concrete slab and the other half remained clean as a reference zone. After this step the overlay concrete was cast on the surface of both concrete slabs. Four weeks later the test of the tensile bond strength was performed to observe where the strength has been poor and where the fracture of the concrete slabs has been, in other words if the fracture will be whether in the new-cast overlay concrete, in the bond zone or in the substrate concrete.   Cleanliness has a profound influence on the bond between old and new cast concrete. The tensile strength is poor on the concrete where the surface wasn’t clean enough. The proof is a fracture on the bond between the concrete layers, with less tension force and it is clearly visible dirt such as oil or chips just on the interface when the drilling cylinder is pulled out. To solve this problem it is advised to use a white miracle cloth to be sure that the surface is completely clean before placement of the new-cast concrete.

No description available.

Biodiesel is a renewable and biodegradable fuel that has the possibility to replace conventional diesel fuel and reduce the environmental pollution. Despite its environmental benefits, it has been shown to cause damage to the vehicle engines, due to its oxidative properties. Different metals, such as copper, zinc and aluminium are present in the vehicle fuel system and have been shown to catalyse the oxidation of biodiesel. Several studies have been performed to investigate the interaction between these metals and fuel. However, some reports concluded contradicting results when it comes to the oxidation of biodiesel in contact with aluminium alloys. This project aimed therefore to investigate and create a simple method for comparing the catalytic effect on oxidation for metals, and use this method to evaluate the degradation rate of biodiesel in contact with aluminium alloys. Different heating methods and coating materials were tested using the biodiesel RME to develop the testing procedure. When a test procedure was established, three filter houses made from cast aluminium alloy and three aluminium ingots with different amount of copper were immersed in RME and the stability was evaluated. The results showed that using an oven at 80 °C to investigate the stability provided the most repeatable results, and the spray paint Auto K billack spray Universal appeared to be compatible to use with RME. The inner untreated surface of the fuel filter houses did not seem to increase the oxidation rate of biodiesel. Aluminium alloys with higher copper content degraded RME more than aluminium alloys with little/no copper, if the surface had been treated mechanically, but not to a large extent. This concludes that aluminium alloys may reduce the stability of biodiesel if it contains much copper and if the surface of the alloy has been treated. However, the detected reduction on oxidation stability could depend on other factors, and therefore it is recommended to conduct further experiments on test the aluminium alloys. / Biodiesel är ett förnybart och biologiskt nedbrytbart bränsle som har möjligheten att ersätta konventionell diesel och minska föroreningen av miljön. Trots dess fördelar så har det visats att bränslet skadar motorerna i fordon, vilket beror på dess oxidativa egenskaper. Olika metaller, såsom koppar, zink och aluminium förekommer i fordons bränslesystem, och dessa har påvisats katalysera oxidationen av biodiesel. Flera studier har genomförts där interaktionen mellan de tidigare nämnda metallerna och biodiesel har undersökts. En del av dessa studier har fått motsägelsefulla resultat när det kommer till interaktionen mellan aluminium legeringar ochbiodiesel. Detta projekt har därför haft som syfte att ta fram en enkelt metod att jämföra metallers katalystiska effekt på biodieslets oxidations stabilitet, samt använda denna metod för att bedöma nedbrytningen av biodiesel i kontakt med aluminium legeringar. Olika uppvärmningsmetoder och täckningsmaterial undersöktes med hjälp av biodiesel gjord på rapsolja, RME, för att ta fram mätmetoden. När ett tillvägagångssätt hade fastlagts, så sänktes bitar av tre olika bränslefilterhus tillverkade av aluminium legeringar, och tre olika aluminium tackor med olika kopparhalter i RME och bränslets stabilitet mättes. Användning av ugn vid 80 °C för att testa biodieslets oxidations stabilitet gav de mest upprepbara resultaten, och sprejfärgen Auto K billack spray Universal var mest kompatibel att använda som täckningsmaterial. Den inre, obehandlade ytan av bränslefilterhusen visade sig inte påverka oxidations stabiliteten på biodieslet. Aluminijm legeringar med en högre koppar halt bröt ned RME lite mer än aluminium legeringar med lite/ingen koppas, men endast om ytan hade blivit mekaniskt behandlad. Detta ger slutsatsen att aluminium legeringar kan minska biodieslets stabilitet om det innehåller mycket koppar och om legeringens yta har blivit behandlad. Däremot så kan den reduktionen av oxidations stabiliteten bero på andra faktorer och det rekommenderas därför att genomföra fler experiment med aluminum legeringar och biodiesel.

Biodiesel is a renewable and biodegradable fuel that has the possibility to replace conventional diesel fuel and reduce the environmental pollution. Despite its environmental benefits, it has been shown to cause damage to the vehicle engines, due to its oxidative properties. Different metals, such as copper, zinc and aluminium are present in the vehicle fuel system and have been shown to catalyse the oxidation of biodiesel. Several studies have been performed to investigate the interaction between these metals and fuel. However, some reports concluded contradicting results when it comes to the oxidation of biodiesel in contact with aluminium alloys. This project aimed therefore to investigate and create a simple method for comparing the catalytic effect on oxidation for metals, and use this method to evaluate the degradation rate of biodiesel in contact with aluminium alloys. Different heating methods and coating materials were tested using the biodiesel RME to develop the testing procedure. When a test procedure was established, three filter houses made from cast aluminium alloy and three aluminium ingots with different amount of copper were immersed in RME and the stability was evaluated. The results showed that using an oven at 80 °C to investigate the stability provided the most repeatable results, and the spray paint Auto K billack spray Universal appeared to be compatible to use with RME. The inner untreated surface of the fuel filter houses did not seem to increase the oxidation rate of biodiesel. Aluminium alloys with higher copper content degraded RME more than aluminium alloys with little/no copper, if the surface had been treated mechanically, but not to a large extent. This concludes that aluminium alloys may reduce the stability of biodiesel if it contains much copper and if the surface of the alloy has been treated. However, the detected reduction on oxidation stability could depend on other factors, and therefore it is recommended to conduct further experiments on test the aluminium alloys. / Biodiesel är ett förnybart och biologiskt nedbrytbart bränsle som har möjligheten att ersätta konventionell diesel och minska föroreningen av miljön. Trots dess fördelar så har det visats att bränslet skadar motorerna i fordon, vilket beror på dess oxidativa egenskaper. Olika metaller, såsom koppar, zink och aluminium förekommer i fordons bränslesystem, och dessa har påvisats katalysera oxidationen av biodiesel. Flera studier har genomförts där interaktionen mellan de tidigare nämnda metallerna och biodiesel har undersökts. En del av dessa studier har fått motsägelsefulla resultat när det kommer till interaktionen mellan aluminium legeringar ochbiodiesel. Detta projekt har därför haft som syfte att ta fram en enkelt metod att jämföra metallers katalystiska effekt på biodieslets oxidations stabilitet, samt använda denna metod för att bedöma nedbrytningen av biodiesel i kontakt med aluminium legeringar. Olika uppvärmningsmetoder och täckningsmaterial undersöktes med hjälp av biodiesel gjord på rapsolja, RME, för att ta fram mätmetoden. När ett tillvägagångssätt hade fastlagts, så sänktes bitar av tre olika bränslefilterhus tillverkade av aluminium legeringar, och tre olika aluminium tackor med olika kopparhalter i RME och bränslets stabilitet mättes. Användning av ugn vid 80 °C för att testa biodieslets oxidations stabilitet gav de mest upprepbara resultaten, och sprejfärgen Auto K billack spray Universal var mest kompatibel att använda som täckningsmaterial. Den inre, obehandlade ytan av bränslefilterhusen visade sig inte påverka oxidations stabiliteten på biodieslet. Aluminijm legeringar med en högre koppar halt bröt ned RME lite mer än aluminium legeringar med lite/ingen koppas, men endast om ytan hade blivit mekaniskt behandlad. Detta ger slutsatsen att aluminium legeringar kan minska biodieslets stabilitet om det innehåller mycket koppar och om legeringens yta har blivit behandlad. Däremot så kan den reduktionen av oxidations stabiliteten bero på andra faktorer och det rekommenderas därför att genomföra fler experiment med aluminum legeringar och biodiesel.

Self-consolidating concrete (SCC) is a special type of concrete that flows under its own weight and spreads readily into place while remaining stable. Although SCC technology has been rapidly progressing over the last 20 years and continues to develop, the relationships between the fresh, hardened and durability properties of SCC are not well documented. The focus of this investigation is twofold. Firstly, the use of SCC necessitates reliable and accurate characterization of material properties. A variety of laboratory test methods are used to evaluate SCC’s plastic properties. Recognizing that various test methods evaluate the same plastic properties, there is a need to critically investigate the adequacy and sensitivity of each test. Secondly, outcomes from this project are expected to advance the fundamental understanding of the interplay between the fresh properties of SCC and their implications on hardened properties and durability performance.

Self-consolidating concrete (SCC) is a special type of concrete that flows under its own weight and spreads readily into place while remaining stable. Although SCC technology has been rapidly progressing over the last 20 years and continues to develop, the relationships between the fresh, hardened and durability properties of SCC are not well documented. The focus of this investigation is twofold. Firstly, the use of SCC necessitates reliable and accurate characterization of material properties. A variety of laboratory test methods are used to evaluate SCC’s plastic properties. Recognizing that various test methods evaluate the same plastic properties, there is a need to critically investigate the adequacy and sensitivity of each test. Secondly, outcomes from this project are expected to advance the fundamental understanding of the interplay between the fresh properties of SCC and their implications on hardened properties and durability performance.