Direct Write (DW) defines an emerging group of technologies that allow the printing of electronic and other functional components out of vacuum, directly onto conformal surfaces. Both ink-jet and nozzle deposition technologies, which are seen to be complementary for the wide range of materials and processing required by industry, are employed in this project.Silver neodecanoate salt is sensitive to both light source, including ultra violet light (UV) and heat source, and is a good inkjet printing precursor when dissolved in xylene. We have studied the electrical properties of inkjet printed silver samples, derived from silver neodecanoate ink, and investigated the influence of UV treatment before thermal curing the silver samples. UV exposure at room temperature is believed to control the nucleation of silver particles. In addition we have studied the influence of thermal pre-treatment on the printed samples. This pre-treatment is thought to assist the neodecanoate precursor to form a uniform distribution of silver nanoparticles. The influence of UV exposure, thermal pre-treatment and the thermal curing conditions on subsequent track microstructure, and its influence on electrical resistivity is reported for glass substrates. Furthermore, a series of extruding experimental at different nozzle offset and pumping pressure settings are conducted based on the rheological property of silicone oil and silver paste to find the ideal condition for producing continuous tracks with good shape. These findings are used to simulate a computer model for further applications.

The hydration behavior of the calcium aluminates as a function of the glass content, the curing temperature, and the water-solid ratio was investigated. In order to keep them from influencing the results, the free-lime content and the surface area of all samples were kept constant, whenever possible. Samples were hydrated with a water-solid ratio of 10/1 for periods of 1 to 90 days. Three curing temperatures were studied; 2°C, 25°C, and 50°C. Samples were hydrated in tightly sealed polyethylene containers to prevent reactions with atmospheric carbon dioxide. The hydration was followed by X-ray diffraction and thermal analysis. Only two samples, Hexacalcium Tetra-alumino Magnesium Silicate and Tricalcium Magnesium Dialuminate, were successfully prepared in an amorphous form. These compounds were used to investigate the effect of glass content on the hydration behavior. Results indicate that when the glass content is increased a corresponding increase is found in the percent combined water. Samples hydrated at 25°C were influenced by changes in the glass content to a greater degree than were those hydrated at either 2°C or 50°C. The effect of the water-solid ratio on the hydration behavior of the calcium aluminates was studied using the compounds; Hexacalcium Tetra-Alumino Magnesium Silicate/ and Dodecacalcium Hepta-Aluminate. In general, samples that were hydrated with large water-solid ratios reacted more completely than did those hydrated with small water-solid ratios. The presence of sufficient water to theoretically hydrate the samples to completion did not guarantee that the sample would do so. The curing temperature influenced the hydration behavior to a greater degree than did the glass content or the water-solid ratio. Increasing the curing temperature not only increased the rate of hydration, but, in some cases, also changed the hydration products.

The main result of underground mining extraction is creating of large underground voids (mine stopes). These empty openings are typically backfilled with an engineering cementitious material called cemented paste backfill (CPB). The main purpose of CPB application in underground mining is to provide stability and ensure the safety of underground openings, maximize ore recovery, and also provide an environmental-friendly means of underground disposal of potential acid generating tailings. CPB is a mixture of mine tailings, cement binder and water. CPB has a complex geotechnical behaviour when poured into mine voids. This is because of the different thermal (T), hydraulic (H), mechanical (M) and chemical coupled processes and interactions that take place in CPB soon after placement. In addition to these THMC behaviours, various external factors, such as stope geometry, drainage condition and arching effects add more complexity to its behaviour. In order to acquire a full understanding of CPB behaviour, there is a need to consider all of these THMC factors and processes together. So far, there has not been any study that addresses this research need. Indeed, fundamental knowledge of the THMC behaviour of CPB provides a key means for designing safe and cost-effective backfill structures, as well as optimizing mining cycles and productivity of mines. Innovative experimental tools and CPB testing methods have been developed and adopted in this research to fulfill the objectives of this research. In the first phase of the study, experiments with high columns are developed to study the THMC behaviour of CPB from early to advanced ages with respect to height of the column and curing time. The column experiments simulate the mine stope and filling sequence and provide an opportunity to study external factors, such as evaporation, on the THMC behaviour of CPB. However, an important factor is the overburden pressure from the stress due to self-weight that cannot be simulated through column experiments. Therefore, in the second phase of this study, a novel THMC curing under stress apparatus is developed to study the THMC behaviour of CPB under various pressures due to the self-weight of the CPB, drainage conditions, and filling rate and sequence. Comprehensive instrumentation and geotechnical testing are carried out to obtain fundamental knowledge on the THMC behaviour of CPB in different curing conditions from early to advanced ages. The results of these studies show that the THMC properties of CPB are coupled. Important parameters, such as curing stress, self-desiccation due to cement hydration, temperature, pore water chemistry, and mineralogical and chemical properties of the tailings, have significant influence on the shear strength and compressive strength development of CPB. Factors such as evaporation and drying iii shrinkage can also affect the hydro-mechanical properties of CPB. The curing conditions (such as curing stress, drainage and filling rate) also has significant impact on CPB behaviour and performance. The THMC interactions and the degree of influence of each factor should be included in designing backfill structures and planning mining cycles. This innovative curing under stress technique can be replaced the conventional curing of CPB (curing under zero stress and no THMC loadings), in order to optimize CPB mechanical strength assessment, increase mine safety and enhance the productivity.

The diploma thesis deals with the study of hydration of reactive powder concrete under hydrotermal conditions. The theoretical part describes the properties of materials and additives used for the preparation of mixtures. The following describes the principles and requiments for the materials for preparing the reactive powder concrete. The practical part is studied design method mix and the impact of materials to the consistency of paste. The effect of cample placement on flexural and compressive strength of the prepared mixtures was observed. The samples were stored under standart laboratory conditions and under hydrothermal conditions. The phase composition of the samples was monitored by X-ray diffraction analysis and the mocrostructure by scanning electron microscopy.

No description available.

Diplomová práce je zaměřena na přípravu koloidních suspenzí, vytvrditelných UV zářením, jenž jsou určeny k 3D tisku komplexních keramických vláknových struktur. Rovněž jsou v práci představeny techniky následného tvarování vytisknutých a vytvrzených struktur. Z hydroxyapatitu ve formě prášku a komponent, vytvrditelných UV zářením, byly vytvořeny pasty, určené k 3D tisku komplexních keramických vláknových struktur a multivrstev. U takto vytisknutých a vytvrzených struktur bylo navíc dosaženo zlepšení kvality povrchu a soudržnosti vláken. Pro výrobu past, určených k 3D tisku, s vhodnými reologickými vlastnostmi je nezbytné důkladné pochopení interakcí mezi částicemi, surfaktantem a monomerní/oligomerní směsí. Za použití lineárních a zesíťujících oligomerů jako disperzního média vznikají po tisku a UV vytvrzení velmi flexibilní vláknové mřížky, které lze dále tvarovat a takto vytvářet rozmanité struktury. Tyto struktury jsou následně slinuty, bez významných vad na povrchu či delaminace vrstev, za vzniku složitých keramických těles. Vysoké kvality povrchu je dosaženo UV vytvrzením vytisknutých struktur v argonové atmosféře, která brání kyslíkové inhibici radikálů v blízkosti povrchu vláken. Výhody kombinace 3D tisku s UV vytvrzováním jsou demonstrovány v této práci za užití dvouvrstvých flexibilních struktur, určených k následným metodám 3D tvarování. Takto vytvořených složitých 3D struktur je jen velmi obtížné, ne-li nemožné, dosáhnout pouze užitím přímého 3D tisku. Na základě této práce může být v budoucnu odvozena univerzální teorie k přípravě past, určených k 3D tisku komplexních keramických struktur pro různé aplikace.

Reactive powder composites (RPC) have been recently a subject of many researches of modern concrete technology. This type of concrete is very fine and its behaviour exceeds the other types of concrete, therefore there are new possibilities of its use. The design and production of RPC is complex technology process which needs to gain new results in RPC research to get the best features regarding its higher price. This thesis is focused on design of reactive powder concrete (RPC200), which compressive strength is between 200 – 300 MPa. Next goal is to prove the influence of curing regimes like high temperature or pressure, and also check the possibilities of production of low cement reactive powder composite (LCRPC).

I Sverige produceras varje år grovt uppskattat ca. 1,5–2,0 miljoner m2 industrigolv av betong [1]. Resultaten är varierande och det vanligaste felet hos dessa golv är sprickor [2]. I sprickorna letar sig vatten och i vissa fall klorider ned och förorsakar armeringskorrosion. Armeringen expanderar pga. korrosionen och spränger sönder betongen. Golvet blir inte längre estetiskt tilltalande samtidigt som livslängden förkortas avsevärt och golvytan blir ojämn vilket försvårar eventuell trucktrafik. Sprickor uppkommer främst pga. tvångskrafter som uppstår när betongen krymper. Storleken på sprickorna avgörs av betongens benägenhet att krympa, armerings-innehåll och graden av tvång. DynaMate som bygger och underhåller Scanias serviceverkstäder och industrilokaler upplever stora problem med sprickbildning hos industrigolven. Sprickorna medför stora kostnader i form av driftstopp, rivning, reparation och eventuell nyproduktion [3]. Föreliggande rapport baseras framförallt på litteraturstudier utifrån en rad rapporter, artiklar och handböcker men även normer. Intervjuer har genomförts med sakkunniga personer för att ta del av deras erfarenheter och åsikter. För att även få bättre insikt i utförandeskedet har författarna närvarat vid två olika gjutningar av industrigolv. För att minska sprickrisken i betonggolv, orsakad av betongens fria krympning, krävs en betongsammansättning som minimerar den fria krympningen, ett armeringsinnehåll som överstiger minimiarmering, fogar som tillåter rörelser i plattan och en långsam uttorkning. Det har upplevts att problem med sprickor i betonggolv beror på okunskap, olika viljor och slarv bland involverade aktörer. Därför är det även viktigt med tydliga mål och bra kommunikation mellan alla aktörer. På uppdrag av DynaMate har ett förslag till åtgärdsprogram för minskad sprick-bildning tagits fram. Detta kan ligga till grund för framtida golvprojekt och på sikt minska de stora kostnader som underhåll och reparationer medför. / Roughly estimated 1,5–2,0 million m2 of industrial concrete floors are produced in Sweden every year [1]. The results vary and the most common matter/failure among these floors is cracks [2]. Water finds its way down in the cracks and in some cases chlorides, which causes corrosion of the reinforcement. The reinforcement expands due to the corrosion and makes the concrete burst. The floor is no longer esthetically appealing. At the same time the lifetime is shortened substantially and the floor surface becomes uneven which complicates any truck traffic. Cracks arise due to restraint forces that develop because of concrete shrinkage. The width of the cracks is determined by the concretes tendency to shrink, reinforcement content and the extent of restraint forces. DynaMate builds and maintains Scania service centers and industrial facilities. They are experiencing major problems with cracking in industrial floors. The cracks bring large costs in terms of downtime, demolition, repair and any new production. The present report is based mainly on literature research from reports, articles and handbooks but also norms. Interviews were performed with qualified persons to share their experiences and opinions. To receive even more knowledge the authors attended two different castings of industrial floors. A reduction of cracking in concrete floors caused by the free shrinkage requires a concrete composition which minimizes the free shrinkage, reinforcement content in excess of minimum reinforcement, a slow drying and joints that allow movements. It was believed that the problem with cracks in concrete floors is due to ignorance, different wills and carelessness among the involved actors. Consequently it is also important to have clear objectives and good communication between all actors. On behalf of DynaMate a proposal for actions to reduce cracking was prepared. That proposal can form the basis for future flooring projects and ultimately reduce the significant costs due to maintenance and repairs.

Antimicrobial resistance (AMR) is concerning because it limits antimicrobial drug treatment options. AMR occurs by the overuse and misuse of antimicrobial drugs. In environmental settings, AMR can disseminate from places of high use, which leads to increased exposure to humans and animals. A previous study from our laboratory group showed extended-spectrum cephalosporinase-producing Escherichia coli/Klebsiella pneumoniae were isolated from fecal samples obtained in rural Cambodian community settings. Based on these isolates, this study has two aims. The first aim was characterization of selected Cambodian isolates with random amplification polymorphic DNA (RAPD) and antibiotic susceptibility test. From RAPD, the selected six isolates are diverse, except for C61 and C66 bacteria isolates with potential clonality. Additionally, the selected isolates are multidrug resistant (MDR) with reduced susceptibility to beta-lactams and fluoroquinolones. The second aim was to assess two developed methodologies, multiplex automated genome engineering (MAGE) and One-Step Curing Plasmid, by validation in bacteria laboratory strain and development for six Cambodian isolates. To modify AMR genetic elements, MAGE uses pMA7-SacB for homologous recombination with oligos for chromosomal gene disruption. Meanwhile, One-Step Curing Plasmid uses pFREE with the CRISPR/Cas9 system for plasmid and self-curing. Validation showed that MAGE can modify 8% of E. coli MG1655 with lacZ control screening oligos and almost 90% are cured from pFREE. Selected Cambodian isolates have antibiotic-resistance plasmids of IncR or IncFII replicon. For usage in Cambodian isolates, pFREE was modified to be pCAM-FREE by cloning IncR and IncFII plasmid as gRNA1 and gRNA5, respectively. Sequencing results showed pCAM-FREE have gRNA5. In conclusion, our study managed to characterize selected Cambodian isolates as MDR and diverse. In a laboratory strain, MAGE and One-Step Curing Plasmid are functional methods. Furthermore, pCAM-FREE was constructed to target IncFII and in the future, MAGE and pCAM-FREE could be tested in Cambodian isolates.

Today, structural adhesives are found extensively in load-bearing engineering applications, as their use can be advantageous compared to other fastening methods. However, the characteristics of adhesives are far more complex, making it challenging to predict their behavior in different service conditions. In addition, environmental factors like temperature and water can affect the performance of an adhesive bond both physically and chemically. This work was initiated by MuoviTech AB and aims to evaluate the performance of structural methyl methacrylate adhesives cured in different environmental conditions. The study began with a literature review to find relevant research and literature about structural adhesives, their material characteristics, and the effects of temperature and water on the performance of adhesive bonds. A market survey was conducted to find products suitable for the experiment, and Araldite 2050, Araldite 2051, Permabond TA4200, 3M DP8810NS, LoctiteHY 4070, and Acralock SA 10-05 were selected together with MuoviTech AB. The laboratory work began with sample preparation in terms of abrasion and cleaning of the surface. The adhesives were applied to the samples, and single-lap joints were prepared and cured in room temperature and normal humidity, as well at 5 °C and underwater, for 24 hours. Single-lap shear tests were performed according to American standard ASTM D3163. Lastly, differential scanning calorimetry (DSC) was utilized for the thermal analysis of the samples cured at 5 °C and underwater. The results showed that neither of the adhesives performed in the range specified in the manufacturers’ technical data sheets (TDS). Lower failure strength and elongation was observed for the samples cured at 5 °C and underwater, compared to the samples cured in the optimal condition. However, Loctite HY 4070 showed an increase in failure strength. The DSC analysis revealed various degrees of post-curing. Further investigation with prolonged curing time and more environmental conditions are recommended. New tests for Loctite HY 4070 is also recommended to confirm the results. / Idag finns strukturella lim i stor utsträckning i bärande tekniska applikationer, eftersom deras användning kan vara fördelaktig jämfört med andra fästmetoder. Limmens egenskaper är dock mycket mer komplexa, vilket gör det svårt att förutsäga deras beteende under olika serviceförhållanden. Dessutom kan miljöfaktorer som temperatur och vatten påverka en limbindnings prestanda både fysiskt och kemiskt. Detta arbete initierades av MuoviTech AB och syftar till att utvärdera prestanda för strukturella metylmetakrylatlim härdade under olika miljöförhållanden. Studien inleddes med en litteraturöversikt för att hitta relevant forskning och litteratur om strukturella lim, deras materialegenskaper och effekterna av temperatur och vatten på limförbandens prestanda. En marknadsundersökning genomfördes för att hitta produkter som var lämpliga för experimentet, och Araldite 2050, Araldite 2051, Permabond TA4200, 3MDP8810NS, Loctite HY 4070 och Acralock SA 10-05 valdes tillsammans med MuoviTech AB. Arbetet i laboratoriet inleddes med provförberedelse genom slipning och rengöring av provens yta. Lim applicerades på proverna och förband med enkla överlapp (single-lap) bereddes och härdades i rumstemperatur och normal fuktighet, liksom vid 5 ° C och under vatten, under 24 timmar. Skjuvtester utfördes enligt den amerikanska standarden ASTM D3163. Slutligen användes differentiell svepkalorimetri (DSC) för termisk analys av proverna som härdades vid 5 ° C och under vatten. Resultaten visade att inget av limmen presterade i enlighet med det som beskrevs i tillverkarnas tekniska datablad (TDS). Däremot så observerades en lägre brottstyrka och töjning för proverna som härdades vid 5 ° C och under vatten, jämfört med de prover som härdades i det optimala tillståndet. Loctite HY 4070 visade emellertid en ökning av brottstyrka. DSC-analysen gav indikation på att olika grader av efterhärdning. Ytterligare undersökningar med längre härdningstid och med flera miljöförhållanden rekommenderas. Nya tester för Loctite HY 4070 rekommenderas också för att bekräfta resultaten.