This thesis presents research of two novel magnetic materials, LiHoF4 and Tb2Ti2O7. Experiments were performed at low temperatures and in an applied magnetic field to study thermal expansion and magnetostriction using a capacitive dilatometer designed during this project. This thesis presents 3 distinct topics. This manuscript begins with a thermodynamic description of thermal expansion and magnetostriction. The design of a capacitive dilatometer suitable for use at ultra-low temperatures and in high magnetic fields is presented. The thermal expansion of oxygen free high conductivity copper is used as a test of the absolute accuracy of the dilatometer. The first material studied using this dilatometer was LiHoF4. Pure LiHoF4 is a dipolar coupled Ising ferromagnet and in an applied transverse magnetic field is a good representation of the transverse field Ising model. An ongoing discrepancy between theoretical and experimental work motivates further study of this textbook material. Presented here are thermal expansion and magnetostriction measurements of LiHoF4 in an applied transverse field. We find good agreement with existing experimental work. This suggests that there is some aspect of LiHoF4 or the effect of quantum mechanical fluctuations at finite temperatures which is not well understood. The second material studied is the spin liquid Tb2Ti2O7. Despite theoretical predictions that Tb2Ti2O7 will order at finite temperature, a large body of experimental evidence demonstrates that spins within Tb2Ti2O7 remain dynamic to the lowest temperatures studied. In addition Tb2Ti2O7 also exhibits anomalous thermal expansion below 20K, giant magnetostriction, and orders in an applied magnetic field. Thermal expansion and magnetostriction measurements of Tb2Ti2O7 are presented in applied longitudinal and transverse fields. Zero-field thermal expansion measurements do not repeat the previously observed anomalous thermal expansion. A large feature is observed in thermal expansion at 100mK, in rough agreement with existing experimental work. Longitudinal and transverse magnetic fields were applied to Tb2Ti2O7. Longitudinal magnetostriction measurements show qualitatively di erent behavior than previous observations. These measurements were taken along di erent crystal axes so direct comparison cannot be made. Thermal expansion measurements in an applied transverse field show evolution with the strength of the applied field. This evolution may relate to an ordering transition, however difficulties in repeatability in a transverse field require that these results be repeated in an improved setup.

This thesis describes three different design projects that are intellectually connected by the fact that they all involve the development of apparatus to facilitate the precise control of sample temperature in modern microscopes. The first project is a low-temperature sample stage, for a beetle-type scanning tunnelling microscope. The design for this sample stage, and images taken on it with atomic resolution at 114 K are presented. This stage has the capability for variable-temperature sample cooling, which is also discussed. The second project is a set of low- and variable-temperature isothermal radiation shields for a new microscope that is currently being designed and assembled by our research group. These shields provide temperature control between 5 K and room temperature, with measured stability better than +/- 0.1 K. Controlled and stable temperature changes at rates up to 1.5 K per minute have been produced. The shields are modular and can easily accommodate future modifications. The design for the shields, along with their cooling and temperature control capabilities, is presented. The third project is a new stage design for heating, cleaning, and transferring metal and semiconductor samples. Also for use with the new microscope, this stage uses electron bombardment to provide precision temperature control between room temperature to temperatures in excess of 1250 C‰. With this stage, the sample temperature can be determined by measuring the power applied to the sample. The design of this stage, its heating performance, and a method to calculate the sample temperature is presented. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2008-06-03 12:47:18.808

Thermal and fatigue cracking are pavement distresses that deteriorate asphalt pavements in Canada. However, the current AASHTO M320 standard specification protocol does not give satisfactory correlation between the properties measured in the laboratory to thermal and fatigue cracking performance of the asphalt in service. This thesis is aimed at validating the newly developed MTO LS-299 and LS-308 specification test methods for predicting pavement distress. A secondary objective is to determine how well laboratory-aged and field-aged binders correlate with each other in terms of their chemical and physical properties. Chemical testing using infrared (IR) spectroscopy and X-ray fluorescence (XRF), as well as physical and mechanical testing using the regular bending beam rheometer (BBR), extended BBR (eBBR), dynamic shear rheometer (DSR), and double edge notched tension (DENT) tests were performed on laboratory-aged and recovered binders from Highway 417. Asphalt cements with significant amounts of waste engine oil residues as determined by XRF data were found to have cracked severely due to their high tendency for chemical aging. Western Canadian binders modified with styrene-butadiene-styrene polymer showed low affinity for both chemical and physical aging as determined from their carbonyl indices. Asphalt binders with smaller paraffinic structures exhibited insignificant pavement deterioration while the opposite occurred to those with low aromatic indices according to their IR data. The DSR data show that chemical aging occurs much faster in the laboratory-aged binders than the field-aged binders. The DENT test is able to separate superior performing binders from inferior ones with 86% accuracy according to their CTOD data. The regular BBR gave poor correlation between the laboratory test methods and the performance of the pavements. Good correlation exists between the laboratory test methods and the performance of the pavements in service according to the eBBR data. Pavements without any cracks showed lower grade losses, while pavements with severe thermal cracking recorded higher grade losses after three days of conditioning prior to testing. The study has shown that the eBBR and DENT tests are better tools for predicting pavement performance and provide good specification tests for the control of thermal and fatigue cracking in modern pavements. / Thesis (Master, Chemistry) -- Queen's University, 2012-02-28 13:16:02.222

Research on nanomaterials has become increasingly popular because of their unique physical, chemical, optical and catalytic properties compared to their bulk counterparts. Therefore, many efforts have been made to synthesize multidimensional nanostructures for new and efficient nanodevices. Among those materials, zinc oxide (ZnO), has gained substantial attention owing to many outstanding properties. ZnO besides its wide bandgap of 3.34 eV exhibits a relatively large exciton binding energy (60 meV) at room temperature which is attractive for optoelectronic applications. Likewise, cupric oxide (CuO), having a narrow band gap of 1.2 eV and a variety of chemo-physical properties that are attractive in many fields. Moreover, composite nanostructures of these two oxides (CuO/ZnO) may pave the way for various new applications. This thesis can be divided into three parts concerning the synthesis, characterization and applications of ZnO, CuO and their composite nanostructures. In the first part the synthesis, characterization and the fabrication of ZnO nanorods based hybrid light emitting diodes (LEDs) are discussed. The low temperature chemical growth method was used to synthesize ZnO nanorods on different substrates, specifically on flexible non-crystalline substrates. Hybrid LEDs based on ZnO nanorods combined with p-type polymers were fabricated at low temperature to examine the advantage of both materials. A single and blended light emissive polymers layer was studied for controlling the quality of the emitted white light. The second part deals with the synthesis of CuO nanostructures (NSs) which were then used to fabricate pH sensors and exploit these NSs as a catalyst for degradation of organic dyes. The fabricated pH sensor exhibited a linear response and good potential stability. Furthermore, the catalytic properties of petals and flowers like CuO NSs in the degradation of organic dyes were studied. The results showed that the catalytic reactivity of the CuO is strongly depending on its shape. In the third part, an attempt to combine the advantages of both ZnO and CuO NSs was performed by developing a two-step chemical growth method to synthesize the composite NSs. The synthesized CuO/ZnO composite NSs revealed an extended light absorption and enhanced defect related visible emission.

The incorporation of active piezoelectric elements and fluidic components into micro-electromechanical systems (MEMS) is of great interest for the development of sensors, actuators, and integrated systems used in microfluidics. Low temperature cofired ceramics (LTCC), widely used as electronic packaging materials, offer the possibility of manufacturing highly integrated microfluidic systems with complex 3-D features and various co-firable functional materials in a multilayer module. It would be desirable to integrate high performance lead zirconate titanate (PZT) based ceramics into LTCC-based MEMS using modern thick film and 3-D packaging technologies. The challenges for fabricating functional LTCC/PZT devices are: 1) formulating piezoelectric compositions which have similar sintering conditions to LTCC materials; 2) reducing elemental inter-diffusion between the LTCC package and PZT materials in co-firing process; and 3) developing active piezoelectric layers with desirable electric properties. The goal of present work was to develop low temperature fired PZT-based materials and compatible processing methods which enable integration of piezoelectric elements with LTCC materials and production of high performance integrated multilayer devices for microfluidics. First, the low temperature sintering behavior of piezoelectric ceramics in the solid solution of Pb(Zr0.53,Ti0.47)O3-Sr(K0.25, Nb0.75)O3 (PZT-SKN) with sintering aids has been investigated. 1 wt% LiBiO2 + 1 wt% CuO fluxed PZT-SKN ceramics sintered at 900oC for 1 h exhibited desirable piezoelectric and dielectric properties with a reduction of sintering temperature by 350oC. Next, the fluxed PZT-SKN tapes were successfully laminated and co-fired with LTCC materials to build the hybrid multilayer structures. HL2000/PZT-SKN multilayer ceramics co-fired at 900oC for 0.5 h exhibited the optimal properties with high field d33 piezoelectric coefficient of 356 pm/V. A potential application of the developed LTCC/PZT-SKN multilayer ceramics as a microbalance was demonstrated. The final research focus was the fabrication of an HL2000/PZT-SKN multilayer piezoelectric micropump and the characterization of pumping performance. The measured maximum flow rate and backpressure were 450 μl/min and 1.4 kPa respectively. Use of different microchannel geometries has been studied to improve the pumping performance. It is believed that the high performance multilayer piezoelectric devices implemented in this work will enable the development of highly integrated LTCC-based microfluidic systems for many future applications.

Low temperature co-fired ceramic (LTCC) electronic packaging materials are applied for their electrical and mechanical properties, high reliability, chemical stability and ease of fabrication. Three dimensional features can also be prepared allowing integration of microfluidic channels and cavities inside LTCC modules. Mechanical, optical, electrical, microfluidic functions have been realized in single LTCC modules. For these reasons LTCC is attractive for biomedical microfluidics and Lab-on-a-Chip systems. However, commercial LTCC systems, optimized for microelectrics applications, have unknown cytocompatibility, and are not compatible with common surface functionalization chemistries. The first goal of this work is to develop biocompatible LTCC materials for biomedical applications. In the current work, two different biocompatible LTCC substrate materials are conceived, formulated and evaluated. Both materials are based from well-known and widely utilized biocompatible materials. The biocompatibilities of the developed LTCC materials for in-vitro applications are studied by cytotoxicity assays, including culturing endothelial cells (EC) both in LTCC leachate and directly on the LTCC substrates. The results demonstrate the developed LTCC materials are biocompatible for in-vitro biological applications involving EC. The second goal of this work is to develop functional capabilities in LTCC microfluidic systems suitable for in-vitro and biomedical applications. One proposed application is the evaluation of oxygen tension and oxidative stress in perfusion cell culture and bioreactors. A Clark-type oxygen sensor is successfully integrated with LTCC technique in this work. In the current work, a solid state proton conductive electrolyte is used to integrate an oxygen sensor into the LTCC. The measurement of oxygen concentration in Clark-type oxygen sensor is based on the electrochemical reaction between working electrode and counter electrode. Cyclic voltammetry and chronoamperometry are measured to determine the electrochemical properties of oxygen reduction in the LTCC based oxygen sensor. The reduction current showed a linear relationship with oxygen concentration. In addition, LTCC sensor exhibits rapid response and sensitivity in the physiological range 1─9 mg/L. The fabricated devices have the capabilities to regulate oxygen supply and determination of local dissolved oxygen concentration in the proposed applications including perfusion cell culture and biological assays.

Low temperature cracking is a major distress in asphalt pavements. Several test configurations have been introduced to characterize the fracture properties of hot mix (HMA); however, most are considered to be research tools due to the complexity of the test methods or equipment. This dissertation describes the development of the indirect ring tension (IRT) fracture test for HMA, which was designed to be an effective and user-friendly test that could be deployed at the Department of Transportation level. The primary advantages of this innovative and yet practical test include: relatively large fracture surface test zone, simplicity of the specimen geometry, widespread availability of the required test equipment, and ability to test laboratory compacted specimens as well as field cores. Numerical modeling was utilized to calibrate the stress intensity factor formula of the IRT fracture test for various specimen dimensions. The results of this extensive analysis were encapsulated in a single equation. To develop the test procedure, a laboratory study was conducted to determine the optimal test parameters for HMA material. An experimental plan was then developed to evaluate the capability of the test in capturing the variations in the mix properties, asphalt pavement density, asphalt material aging, and test temperature. Five plant-produced HMA mixtures were used in this extensive study, and the results revealed that the IRT fracture test is highly repeatable, and capable of capturing the variations in the fracture properties of HMA. Furthermore, an analytical model was developed based on the viscoelastic properties of HMA to estimate the maximum allowable crack size for the pavements in the experimental study. This analysis indicated that the low-temperature cracking potential of the asphalt mixtures is highly sensitive to the fracture toughness and brittleness of the HMA material. Additionally, the IRT fracture test data seemed to correlate well with the data from the distress survey which was conducted on the pavements after five years of service. The maximum allowable crack size analysis revealed that a significant improvement could be realized in terms of the pavements performance if the HMA were to be compacted to a higher density. Finally, the IRT fracture test data were compared to the results of the disk-shaped compact [DC(t)] test. The results of the two tests showed a strong correlation; however, the IRT test seemed to be more repeatable.

In a time where energy efficiency and saving measures are becoming more common terms in the energy industry, it is necessary to examine the district heating networks. One of the possible measures for efficient district heating is low-temperature secondary system. This thesis examines the potential benefits available with low temperature secondary heating systems versus conventional primary connections by comparing simulated models with the data collected from existing secondary system. The simulated cases in the report is modeled, calculated and simulated in the software NetSim. The results of the simulations demonstrated a reduced power requirement for the low temperature system with 4.8 kW, which approximately is a decreasing of 6 %. Heat losses from the simulated models turn out to be lower than the actual operating systems as a result of increased temperatures in the network. The difference between the simulated and real operating systems can therefore be useful in future projects for validation. Something that can be seen is that the line density of the secondary networks often is below what is considered as a profitable expansion. This does however not mean that secondary systems should not be built, as more aspects of a low temperature secondary system may be of interest to energy companies. The price models for secondary heat networks that were investigated differ, which could indicate that the market for secondary heat in district heating systems is young and under development. / I en tid där energieffektiviseringar och besparingsåtgärder blir allt mer aktuella begrepp inom energibranschen finns det anledning att undersöka fjärrvärmenäten. En av de tänkbara åtgärderna för effektivare fjärrvärmenät är lågtempererade sekundärsystem. Detta examensarbete undersöker vilka eventuella fördelar som finns med lågtempererade sekundära värmesystem kontra konventionella primäranslutningar, genom att jämföra simulerade modeller med insamlad data från befintliga sekundärsystem. De simulerade fallen i rapporten är modellerade, beräknade och simulerade i programvaran NetSim. I resultatet från simuleringarna påvisas ett minskat effektbehov för de lågtempererade systemet med 4,8 kW, vilket motsvarar en sänkning med ungefär 6 %. Värmeförlusterna från de simulerade modellerna visar sig vara lägre än de faktiska driftfallen till följd av ökade temperaturer i näten. Just skillnaden mellan de simulerade och verkliga driftfallen kan därför bli användbara vid framtida projekt för att validera projekteringen. Något som också kan utläsas är att linjetätheten (levererad MWh/meter kulvertledning) för de sekundära näten ofta understiger vad som anses som en lönsam utbyggnad, det betyder dock inte att sekundära system ej bör byggas, då fler aspekter av ett lågtempererat sekundärnät är av intresse för energibolagen. De prismodeller för sekundärvärme som undersökts skiljer sig åt vilket skulle kunna indikera att marknaden för sekundärvärme är ung och under utveckling.

Energianvändningen i världen ökar vilket medför en ökad belastning på miljön. Många industrier har idag ett överskott av värme som vid ett ökat nyttjande skulle kunna reducera andelen primärenergi och således belastningen på miljön samtidigt som ekonomiska besparingar kan erhållas. DIBO Produktionspartner AB är en verkstadsindustri i Katrineholm som bearbetar metall‐ och plastkomponenter i CNC‐maskiner. Maskinparken består av 14 CNC‐maskiner och en kompressor som förser maskinerna med tryckluft. Ventilationssystemet består av två delar, ett till‐ och frånluftssystem kopplat till verkstaden samt ett FTX‐system kopplat till den intilliggande kontorsbyggnaden. Företaget har idag ett värmeöverskott på grund av aktiviteten från de olika CNC‐ maskinerna och tryckluftskompressorn vilket medför höga temperaturer i verkstaden. I dagsläget öppnas en ytterport för att ventilera ut värmeöverskottet så att en lägre temperatur erhålls. Arbetet syftade till att kvantifiera mängden överskottsvärme tillgänglig i verkstaden för att därefter undersöka möjliga externa och interna användningsområden. Värmeöverskottet uppskattades genom att ställa upp en energibalans för verkstaden där tillskott och förluster av värmeenergi jämfördes. Både tillskotten och förlusterna av värmeenergin beräknades genom inventering av verkstadslokalerna, mätningar av el, temperatur och ventilation samt genom simuleringar av verkstadens inomhusklimat. Värmeöverskott i verkstaden förekommer under årets alla månader, även om det är starkt beroende av utomhustemperaturen och aktiviteten i verkstaden, och uppgår årligen till 137 MWh. Beträffande externa användningsområden studerades faktorer som påverkar ett spillvärmesamarbete, den teknik som skulle behövas för att leverera värme externt och möjligheten för DIBO att leverera värme till Katrineholms fjärrvärmenät. Det finns många faktorer som man bör ha i åtanke vid ett samarbete varav några är förtroendet mellan de båda parterna, investeringsuppdelning samt värdering av spillvärmen. För externa värmeleveranser varierar den utrustning som krävs beroende på de aktuella förhållandena, men generellt gäller att anslutningspunkter, en anslutningsledning och i en del fall en cirkulationspump samt en värmepump för uppgradering av värmen behövs. Som ett resultat av att tryckluftskompressorns effekt är förhållandevis låg och värmen luftburen har en värmepump av lämplig storlek ej hittats. Efter kontakt med Tekniska verken i Katrineholm framgick även att energimängden som skulle kunna levereras är för liten för att ett samarbete ska vara av intresse vilket medför att en leverans till fjärrvärmenätet inte är aktuellt i dagsläget. De interna åtgärderna som studerats finns listade i Tabell 1 där även besparingspotential och återbetalningstid framgår. / The Energy use is increasing throughout the world, which causes an increased load on the environment. Today, a lot of industries have unused waste heat, which by extended use would reduce the amount of primary energy sources and thus the environmental load together with economical savings that would apply for the industry. DIBO Produktionspartner AB is a manufacturing industry that processes metal‐ and plastic components in CNC‐machines. The machinery consists of 14 CNC‐machines and one compressor that provide the machines with compressed air. The ventilation system consists of two systems, one supply and exhaust air system for the workshop and one heat exchange system for the adjacent office building. Due to activity from the machines and compressor, the company has excess heat which causes high temperatures in the workshop. Today, a gate is opened in order to vent the excess heat and lower the temperature. This project’s aim was to quantify the amount of excess heat available in the workshop and afterwards investigate possible internal and external uses. The excess heat was estimated by setting up an energy balance for the workshop where heat energy contributions and losses were compared. Both the contributions and losses of heat energy were calculated by a workshop inventory, electricity, temperature and ventilation measurements and through simulations of the workshop’s indoor climate. Results show that excess heat occurs in the workshop every month of the year, largely dependent on the outdoor temperature and activity level in the workshop, and amounts to 137 MWh yearly. Regarding the external uses, factors that affect waste heat cooperation, technology to deliver heat and the possibility for DIBO to deliver heat to the district heating system in Katrineholm, was evaluated. Among all the factors to keep in mind in cooperation, trust between the parties, investment division and valuation of waste heat, are some. The technology needed to deliver heat varies, but common equipment includes connecting points and lines and in some cases a circulation pump as well as a heat pump for upgrading the heat. As a result of an air compressor with relatively low power and airborne heat, a suiting heat pump has not been found. Contact with Tekniska verken in Katrineholm showed that the potential amount of heat energy deliverable to the district heating system is too small to be of interest and therefor a delivery to the district heating network is today not relevant. The internal measures are listed in Table 1 along with their potential savings and payback time.

The purpose of this study was to determine whether deep-cryogenic freezing produces a change in the timbre or playing characteristics of brass trumpets. The experimental procedure consisted of two parts: quantitative analysis and qualitative analysis. For qualitative analysis a panel of four professional trumpet players evaluated five trumpets: four were frozen and re-evaluated, and one served as the experimental control. Analysis of the harmonic spectra of tones from each instrument provided quantitative data. Since previous studies requiring the analysis of musical instrument tones have suffered from a high degree of variation among tones played by human performers, I constructed a mechanical device that could play tones on the test instruments with greater consistency than is possible with live performers.The changes observed in the qualitative and quantitative analyses are very small, and possibly contradictory. The test panel rated all of the instruments higher after they had been frozen, and any actual improvement in the playing characteristics is suspect because the control instrument received the second highest improvement of the five instruments in the study. In the quantitative analysis, I observed some slight changes in the amplitudes of some of the harmonics in the spectral graphs, but I also observed slight variations in some of the harmonics of the control instrument. Inconsistencies in the performance of the electronic equipment used in the study could account for some of the variation. The instrument that showed the most statistically significant improvements was rated significantly higher in intonation after cryogenic processing, but I was unable to measure any frequency changes in the tones the mechanical embouchure played on the test instruments.Although one may not actually be able to measure differences reported in the qualitative analysis, it is not possible to rule out any acoustical change from cryogenic freezing. In fact, in the quantitative measurements, three of the instruments showed changes greater (some positive and some negative) than the "experimental error" seen in the control instrument's measurements. Additionally, one member of the test panel is convinced that cryogenic freezing has improved his instrument significantly, but the other three trumpeters are ambivalent. / School of Music