The goal is to perform heat measurements examine of selected roofing material samples. Those roofing materials are asphalt shingles, ceramics, and cedar. It’s important to understand the concept of heat transfer, which consists of conduction, convection, and radiation. Research work was reviewed on different infrared devices to see which one would be suitable for conducting my experiment. In this experiment, the main focus was on a specific property of radiation. That property is the emissivity, which is the amount of heat a material is able to radiate compared to a blackbody. An infrared measuring device, such as the infrared camera was used to determine the emissivity of each sample by using a measurement formula consisting of certain equations. These equations account for the emissivity, transmittance of heat through the atmosphere and temperatures of the samples, atmosphere and background. The experiment verifies how reasonable the data is compared to values in the emissivity table. A blackbody method such as electrical black tape was applied to help generate the correct data. With this data obtained, the emissivity was examined to understand what factors and parameters affect this property of the materials. This experiment was conducted using a suitable heat source to heat up the material samples to high temperature. The measurements were taken during the experiment and displayed by the IR camera. The IR images show the behavior of surface temperatures being distributed throughout the different materials. The main challenge was to determine the most accurate emissivity values for all material samples. The results obtained by the IR camera were displayed in figures and tables at different distances, which was between the heap lamp and materials. The materials exhibited different behaviors in temperature and emissivity at certain distances. The emissivity of each material varied with different temperatures. The results led to suggestions of certain materials that could be beneficial and disadvantageous in energy and cost savings during cold and hot seasons of the year. Also this led to some uncertainties in the data generated. Overall, this can support in exploring other ideas to increase energy and cost saving consistently during both season by using a material that can change its color and density based on a high or low temperature.

Submitted in fulfillment of the academic requirements for the Masters of Applied Science (Chemistry), Durban University of Technology, Durban, South Africa, 2016. / In this work, the thermodynamic properties for the binary mixtures containing the ionic liquid (IL): 1-ethyl-3-methylimidazolium ethyl sulphate ([EMIM] [EtSO4]) were calculated. The binary systems studied were {pyridine (Py) or ethyl acetoacetate (EAA) or thiophene (TS) + [EMIM] [EtSO4]}. The results were interpreted in terms of the intermolecular interactions between the (pyridine + IL), (ethyl acetoacetate + IL), and (thiophene + IL) molecules. The physical properties: density, speed of sound, and refractive index were measured for the binary mixtures over the complete mole fraction range using an Anton Paar DSA 5000 M vibrating U- tube densimeter and an Anton Paar RXA 156 refractometer, respectively. The measurements were done at T = (298.15, 303.15, 308.15, 313.15, and 318.15) K and at p = 0.1 MPa. The experimental data was used to calculate the derived properties for the binary mixtures namely:- excess molar volume (V E ), isentropic compressibility (ks), molar refractions (R) and deviation in refractive index (Δn). For the binary mixtures, (Py or EAA or TS + IL), V E was negative throughout the whole composition range which indicates the existence of attractive intermolecular interaction between (pyridine + IL) and (ethyl acetoacetate + IL) for (thiophene + IL), V E was negative at low mole fraction of thiophene and became positive at high mole fraction of thiophene. For the binary mixtures (pyridine + IL), (ethyl acetoacetate + IL), ks was positive indicating that the binary mixtures were more compressible than the ideal mixture. For the binary mixture (thiophene + IL) ks was negative at low thiophene composition and positive at high composition indicating that the binary mixture was less compressible than the ideal mixture at low thiophene composition and more compressible at high composition of thiophene. The molar refraction, R, is positive for the (Py or EAA or TS + IL) binary systems at T = (298.15 – 318.15) K, molar refraction decreases as the organic solvent composition increases. For the binary mixture (pyridine + [EMIM] [EtSO4]), Δn is negative at mole fractions < 0.75 of pyridine and positive at mole fractions >0.75 at all temperatures and decreases with an increase in temperature. For the binary system (ethyl acetoacetate + [EMIM] [EtSO4]), Δn values are positive over the entire composition range and at all temperatures and increases with an increase in temperature. Δn values for the (thiophene + IL) system are negative for mole fractions of thiophene < 0.62 and becomes positive for mole fractions of thiophene > 0.62 and Δn increases with an increase in temperature. The Redlich-Kister smoothing equation was used successfully for the correlation of V E and Δn data. The Lorentz- Lorenz equation gave a poor prediction of V E , but a good prediction of density or refractive index. / M

Submitted in fulfillment of the academic requirements of the degree of Master of Technology, Durban University of Technology, Durban, South Africa, 2016. / The thermophysical properties of the binary mixtures containing biofuel components derived from biomass were determined. Experimental densities, speed of sound, and refractive indices for the binary mixtures (methanol or 1-ethyl-3-methylimidazolium acetate [EMIM][OAc] + furfural or furfuryl alcohol ) were measured at T = (298.15, 303.15, 308.15, 313.15 and 318.15) K. From the experimental data, excess molar volume, E m V , isentropic compressibility, s  , molar refractions, R, and deviation in refractive index, Δn, were calculated. The excess molar volumes were found to be negative for all systems studied. The isentropic compressibility were found to be both positive for the whole composition and temperature range and increases slightly with increasing temperature. The deviation in refractive index was positive over the whole composition range. The obtained values of excess molar volumes and changes of refractive index on mixing were satisfactorily correlated by the Redlich–Kister equation. The Lorentz–Lorenz equation was applied to predict the density and calculate the excess molar volume of the binary mixtures. / M

Thermal transport across three-dimensional Lennard-Jones superlattices, two-dimensional heterostructures of graphene and hexagonal boron nitride (hBN), and in C60 molecular crystals is studied atomistically. The first two systems are studied as finite junctions placed between bulk leads, while the molecular crystal is studied as a bulk. Two computational methods are used: molecular dynamics (MD) simulations and harmonic lattice dynamics calculations in conjunction with the scattering boundary method (SBM). In Lennard-Jones superlattice junctions with a superlattice period of four atomic monolayers at low temperatures, those with mass-mismatched leads have a greater thermal conductance than those with mass-matched leads. We attribute this lead effect to interference between and the ballistic transport of emergent junction vibrational modes. The lead effect diminishes when the temperature is increased, when the superlattice period is increased, and when interfacial disorder is introduced, and is reversed in the harmonic limit. In graphene-hBN heterostructure junctions, the thermal conductance is dominated by acoustic phonon modes near the Brillouin zone center that have high group velocity, population, and transmission coefficient. Out-of-plane modes make their most significant contributions at low frequencies, whereas in-plane modes contribute across the frequency spectrum. Finite-length superlattice junctions between graphene and hBN leads have a lower thermal conductance than comparable junctions between two graphene leads due to lack of transmission in the hBN phonon band gap. The thermal conductances of bilayer systems differ by less that 10% from their single-layer counterparts on a per area basis, in contrast to the strong thermal conductivity reduction when moving to from single- to multi-layer graphene. We model C60 molecules using the polymer consistent force-field and compute the single molecule vibrational spectrum and heat capacity. In the face-center cubic C60 molecular crystal at a temperature of 300 K, we find three frequency peaks in the center-of-mass translations at 20, 30 and 38 cm􀀀1, agreeing with the average frequencies of the three acoustic branches of the frozen phonon model of the same system and suggesting that a phonon description of center-of-mass translations. We use both direct method and Green- Kubo MD simulations to predict the thermal conductivity of the molecular crystals at a temperature of 300 K. We find that the thermal conductivity of the molecular crystal is 20 to 50% lower than that of a reduced order model where only molecular center-ofmass translations are present, suggesting that molecular vibrations and rotations act as significant scattering sources for the center-of-mass phonons.

Microspeakers can overheat and break if not monitored and regulated. This monitoringis usually done by adding a pilot tone that introduces energy to the signal.A problem with this approach is the slow update rate of the temperature estimate.This in combination with a fast temperature rise could result in an audible regulationof the input. By simulating the voice coil temperature these problems couldbe mitigated. In this thesis, two existing grey box models and one novel black boxmodel are estimated for different speakers and evaluated using different signals.The results are promising and indicate that all models can estimate the voice coiltemperature with a mean error below one degree. The tests show that a correctinitialization of the model is crucial. Therefore the suggestion to Cirrus Logic,who hosted this thesis project, is to combine a feedforward model with eithertemperature sensor data from the mobile device or a pilot tone. / Mikrohögtalare kan överhettas och gå sönder ifall temperaturen inte övervakasoch regleras vid behov. Denna övervakning sker med hjälp av en pilotton somtillför energi till högtalarens insignal. Ett problem med denna lösning är att övervakningenär relativt långsam. Detta gör att en snabb temperaturökning kan geen oönskad hörbar reglering av insignalen. Genom att modellera spolens temperaturkan detta problem hanteras. I detta examensarbete tas två fysikaliska modelleroch en konfektionsmodell fram och testas på olika högtalare och signaler.Resultaten är lovande och visar att alla modeller kan skatta spoltemperaturenmed ett medelfel under en grad. Utvärderingen visar att initiering av modellensstarttemperatur är viktig. Därför är förslaget till Cirrus Logic att kombinera en simuleringsmodellsom initieras med antingen temperatursensordata från mobileneller med hjälp av en pilotton.

Ahuna Mons is a 4 km tall mountain on Ceres interpreted as a geologically young cryovolcanic dome. Other possible cryovolcanic features are more ambiguous, implying that cryovolcanism is only a recent phenomenon or that other cryovolcanic structures have been modified beyond easy identification. We test the hypothesis that Cerean cryovolcanic domes viscously relax, precluding ancient domes from recognition. We use numerical models to predict flow velocities of Ahuna Mons to be 10-500 m/Myr, depending upon assumptions about ice content, rheology, grain size, and thermal parameters. Slower flow rates in this range are sufficiently fast to induce extensive relaxation of cryovolcanic structures over 10(8)-10(9) years, but gradual enough for Ahuna Mons to remain identifiable today. Positive topographic features, including a tholus underlying Ahuna Mons, may represent relaxed cryovolcanic structures. A composition for Ahuna Mons of >40% ice explains the observed distribution of cryovolcanic structures because viscous relaxation renders old cryovolcanoes unrecognizable.

The pyrolysis of sec-butyllithium in solution was studied in an attempt to understand the loss of stereo-specificity and the atypical kinetics that have been reported. Additionally, the effect of added lithium alkoxides was studied to determine their effects on the highly reactive sec-butyllithium substrate.

The effects of thermal discharges on the density, distribution, production, and drift of benthic organisms were studied at North Lake reservoir.

Thermal transport behavior of austenite stainless steel stripe (304) and the carbon nano-tubes (CNTs) films of varying thickness are studied using a micropipette thermal sensor. Micropipette sensors of various tip sizes were fabricated and tested for the sensitivity and reliability. The sensitivity deviated by 0.11 for a batch of pipette coated under same physical vapor deposition (PVD) setting without being affected by a tip size. Annealing, rubber coating and the vertical landing test of the pipette sensor proved to be promising in increasing the reliability and durability of the pipette sensors. A micro stripe (80µm × 6µm × 0.6µm) of stainless steel, fabricated using focused ion beam (FIB) machining, was characterized whose thermal conductivity was determined to be 14.9 W/m-K at room temperature. Similarly, the thermal characterization of CNT films showed the decreasing tendency in the thermal transport behavior with the increase in the film thickness.

Piezoelectric composites have been investigated for use in a variety of areas, including flow control, structural control, energy harvesting, and fuel ignition systems. While many of the investigations conducted in these areas have utilized traditional piezo actuation systems, such as unimorphs or stack actuators, a growing number of research groups are examining the increased performance derived from the mechanical advantage, and enhanced domain rotation, found in prestressed unimorph designs. Prestressed devices, like Thunder® and LIPCA, have been shown well suited for a number of applications; however, the price associated with these devices can often prevent them from being implemented. In an effort to produce a low cost unimorph device that possesses a performance-enhancing curved form, the present investigation presents a novel technique for manufacturing prestressed piezoelectric actuators that are capable of meeting the same high displacement and load bearing capabilities exhibited by conventional prestressed devices. The newly proposed mechanically prestressed composite device, or MPC, is similar in form and function to well-documented thermally prestressed devices like Thunder®. However, rather than deriving its characteristic curved form from a thermally induced stress, the present class of devices relies on the resorting force incited in the piezoelectric ceramic upon adhesion to a mechanically deformed substrate to provide both the performance-enhancing prestress and final form of the device. To aid in refinement of the newly proposed design, beam theory was used to model the stress developed within the device. The model allowed designers to investigate the limitations imposed on the performance-enhancing curved form of the device by the stresses developed in the ceramic as a result of the curvature. Findings derived from the model were experimentally verified before a finalized design was specified for the composite, and a number of devices were manufactured. An initial characterization of the device was carried out based on the composite's response to mechanical and electrical loading. By determining the slope of the electrically and mechanically induced displacement response of the device, the investigation was able to define the center displacement constant and effective spring constant of the unimorph. These parameters not only allow designers to predict the displacement that will occur in response to a given electric field or tensile load, but also to allow for comparison with various devices. In the present investigation, the performance characteristics of mechanically prestressed composites were assessed as a function of substrate thicknesses and adhesive properties. With composites constructed using substrates approximately 9.2cm in length, devices were found to have typical center displacement constants on the order of 1.59 to 7.78kV/mm2 while retaining an effective stiffness between 4.5 to 7.5N/mm. These values were found to be similar to the .71 to 3.85kV/mm2 center displacement constants demonstrated by similarly sized and shaped Thunder® devices, which posses an effective stiffness in the range of 10 to 16.3N/mm. A comprehensive presentation of the test methods and procedures used to determine these values, along with other performance characteristics, are provided.