No description available.

3He films adsorbed on graphite were studied down to temperatures below 1 mK using nuclear magnetic resonance (NMR) and heat capacity as probes. This is the first work that combined heat capacity and NMR in the same cell. The substrate used was Grafoil, a form of exfoliated graphite. Continuous wave NMR was measured using conventional Q-meter circuits, whereas heat capacity was measured using the standard adiabatic method. Thermometry was based on a melting curve thermometer, which served as the primary thermometer. A platinum pulsed NMR and a lanthanum diluted cerium magnesium nitrate (LCMN) thermometers, both calibrated against the melting curve thermometer were also employed. The work focused mainly in the study of the nuclear magnetism when the film is in a solid phase. For pure 3He films, submonolayer and second layer films were investigated. Here, it was observed that the Heisenberg model is appropriate to describe both nuclear magnetic susceptibility and heat capacity of this system. However, the discrepancies in the exchange constants inferred from the different experimental probes are attributed to multiple spin exchange effects, in line with what has been observed in bulk solid 3He. Another system studied in this work was 3He adsorbed on two layers of deuterium hydride (HD) preplated graphite. In this case, a cusp in the susceptibility at a temperature of 1 mK, interpreted as indicative of a magnetic phase transition, was a particularly intriguing observation

Thesis (M.S.)--University of Wisconsin--Madison, 1963. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 102-105).

No description available.

No description available.

Heat transfer at the nanoscale has been one of the primary concerns in the design of nanoelectronics and nanostructured materials for applications such as thermal management and thermoelectric energy conversion. This thesis examines the thermal transport in nanoscale thin films and two-dimensional (2D) materials using an optical pump-probe technique based on frequency domain thermoreflectance (FDTR). The design and implementation of a continuous-wave laser based FDTR system is described in detail. The system is extended to an imaging microscope capable of producing micrometer scale maps of several thermophysical properties simultaneously. An analytical formula, which accounts for experimental noise and uncertainty in the controlled model parameters, is derived to calculate the precision of thermoreflectance measurements. The FDTR system is used to study the anisotropic heat conduction in periodic nanoscale Mo/Si superlattices and a 2D material, graphene. The measured in-plane thermal conductivity values of the superlattices are in good agreement with calculations taking into account both electron and phonon thermal transport, using a phonon mean free path which depends on the Mo layer thickness. The measurement procedure of graphene is described in detail, including the sample preparation, sensitivity analysis, and parameter fitting. Various graphene flakes supported on SiO2 surfaces and atomically flat Muscovite mica surfaces are measured. The results show that the thermal conductivity of single-layer graphene can be improved by ~3 times by using a mica substrate compared to commonly used SiO2 substrates. In addition, comparison with the reported values of suspended graphene suggest that the out-of-plane flexural phonon modes may contribute at least 70% to the thermal conductivity of graphene. Finally, the thermal model is modified to include volumetric heating for the measurement of materials without a transducer layer. An amorphous silicon film deposited on fused silica and silicon substrates is measured to validate the model.

A ratiometric laser induced fluorescence (LIF) thermometry applied to micro-scale temperature measurement for natural convection flows. To eliminate incident light non-uniformity and imperfection of recording device, two fluorescence dyes are used: one is temperature sensitive fluorescence dye (Rhodamine B) and another is relatively temperature insensitive fluorescence dye (Rhodamine 110). Accurate and elaborate calibration for intensity ratio verses temperature obtained using an isothermal cuvette, which was controlled by two thermo-bathes. 488nm Ar-ion laser used for incident light and two filter sets used for separating each fluorescence emission. Thermally stratified filed of 10mm channel with micro-scale resolution measured within 1.3?C uncertainty of liner prediction with 23?m x 23?m spatial resolution. Natural convection flows at 10mm channel also observed. The several difficulties for applying to heated evaporating meniscus were identified and a few resolutions were suggested.

No description available.

The Navy is interested in comparing multi-thermocouple probes, tested in the field, with scanned laser absorption thermometry. This comparison aims to understand the effects of excess Carbon Monoxide (CO) and carbon (soot) resulting from rich nitromethane (CH3NO2) combustion events interacting with the outside air, as well as aluminum catalysts, on the temperature of the ensuing fireball. These interactions create mixing zones with varying gas temperature and composition. Currently, research at the UCF shock tube involves taking preliminary CO-scanned thermometry data with the goal of comparing thermocouple insert results in the future. The thermocouple insert is securely positioned within a specially designed end wall and protected by a heat shield. By comparing the temperature measurements obtained by one-dimensional shock relations with those obtained through scanned laser thermometry, based on CO characterization experiments conducted previously on the same shock tube, we aim to analyze temperature measurements and evaluate how the presence of the thermocouple insert affects the incident shockwave geometry, as well as the resulting reflected wave and temperature conditions. The goal is to observe any discrepancies in temperature measurements between the one-dimensional shock relations and the scanned laser method. This will enable researchers to assess the impact of the thermocouple insert in testing environments. Experiments were conducted using a mixture of 3% carbon monoxide (CO), 20% helium (He), and 77% argon (Ar), with an expected temperature range of 950 – 1950K, at pressures of 0.7 – 1 atmosphere (atm).

Background: Diabetic foot neuropathy (DFN) is one of the most important complications of diabetes mellitus; its early diagnosis and intervention can prevent foot ulcers and the need for amputation. Thermometry, measuring the temperature of the feet, is a promising emerging modality for diabetic foot ulcer prevention. However, patient compliance with at-home monitoring is concerning. Delivering messages to remind patients to perform thermometry and foot care might be helpful to guarantee regular foot monitoring. This trial was designed to compare the incidence of diabetic foot ulcers (DFUs) between participants who receive thermometry alone and those who receive thermometry as well as mHealth (SMS and voice messaging) over a year-long study period. Methods/design: This is an evaluator-blinded, randomized, 12-month trial. Individuals with a diagnosis of type 2 diabetes mellitus, aged between 18-80 years, having a present dorsalis pedis pulse in both feet, are in risk group 2 or 3 using the diabetic foot risk classification system (as specified by the International Working Group on the Diabetic Foot), have an operating cell phone or a caregiver with an operating cell phone, and have the ability to provide informed consent will be eligible to participate in the study. Recruitment will be performed in diabetes outpatient clinics at two Ministry of Health tertiary hospitals in Lima, Peru. Interventions: participants in both groups will receive education about foot care at the beginning of the study and they will be provided with a thermometry device (TempStat (TM)). TempStat (TM) is a tool that captures a thermal image of the feet, which, depending on the temperature of the feet, shows different colors. In this study, if a participant notes a single yellow image or variance between one foot and the contralateral foot, they will be prompted to notify a nurse to evaluate their activity within the previous 2 weeks and make appropriate recommendations. In addition to thermometry, participants in the intervention arm will receive an mHealth component in the form of SMS and voice messages as reminders to use the thermometry device, and instructions to promote foot care. Outcomes: the primary outcome is foot ulceration, evaluated by a trained nurse, occurring at any point during the study. Discussion: This study has two principal contributions towards the prevention of DFU. First, the introduction of messages to promote self-management of diabetes foot care as well as using reminders as a strategy to improve adherence to daily home-based measurements. Secondly, the implementation of a thermometry-based strategy complemented by SMS and voice messages in an LMIC setting, with wider implications for scalability.