Yes / Small-angle neutron scattering (SANS) and neutron spin-echo (NSE) have been used to investigate the temperature-dependent solution behaviour of highly-branched poly(N-isopropylacrylamide) (HB-PNIPAM). SANS experiments have shown that water is a good solvent for both HB-PNIPAM and a linear PNIPAM control at low temperatures where the small angle scattering is described by a single correlation length model. Increasing the temperature leads to a gradual collapse of HB-PNIPAM until above the lower critical solution temperature (LCST), at which point aggregation occurs, forming disperse spherical particles of up to 60 nm in diameter, independent of the degree of branching. However, SANS from linear PNIPAM above the LCST is described by a model that combines particulate structure and a contribution from solvated chains. NSE was used to study the internal and translational solution dynamics of HB-PNIPAM chains below the LCST. Internal HB-PNIPAM dynamics is described well by the Rouse model for non-entangled chains.

Captive husbandry programs in zoos have documented nesting behavior and have successfully hatched Manouria emys emys, but data on sex determining mechanisms and sex ratios are absent. A total of 30 M. e. emys eggs were artificially incubated at five different temperatures in constant humidity. Mean incubator temperatures were 24.99°C, 25.06°C, 27.18°C, 28.00°C, and 30.79°C. Incubation duration ranged from 60 days to 92 days, and hatching success was 50%. Sex determined by histology and laparoscopy resulted in male differentiation at low temperatures (24.99°C, 27.18°C) and female differentiation at high temperatures (30.79°C). Pivotal temperature was estimated to be 29.29°C. The following investigation into temperature-dependent sex determination (TSD), including its presence or absence, pattern, and pivotal temperature, has implications for studies of adaptive significance of reproductive behaviors and of chelonian phylogenetic history. Additionally, the proposed study can provide foundations for conservation management decisions, and for captive breeding programs.

This dissertation presents a novel large signal modeling approach which can be used to accurately model CMOS transistors used in millimeter-wave CMOS power amplifiers. The large signal model presented in this work is classified as an empirical compact device model which incorporates temperature-dependency and device periphery scaling. These added features allow for efficient design of multi-stage CMOS power amplifiers by virtue of the process-scalability. Prior to the presentation of the details of the model development, background is given regarding the 90nm CMOS process, device test structures, de-embedding methods and device measurements, all of which are necessary preliminary steps for any device modeling methodology. Following discussion of model development, the design of multi-stage 60GHz Class AB CMOS power amplifiers using the developed model is shown, providing further model validation. The body of research concludes with an investigation into designing a CMOS power amplifier operating at frequencies close to the millimeter-wave range with a potentially higher-efficiency class of power amplifier operation. Specifically, a 24GHz 130nm CMOS Inverse Class F power amplifier is simulated using a modified version of the device model, fabricated and compared with simulations. This further demonstrates the robustness of this device modeling method.

Modeling at the structural scale most often requires the use of beam and shell elements. This simplification reduces modeling complexity and computation requirements but sacrifices the accuracy of through-the-thickness information. Several studies have reported various design approaches for analyzing functionally graded material structures. One of these studies proposed a two-node beam element for functionally graded materials (FGMs) based on first order shear deformable (FOSD) theory. The derivation of governing equations included spatial temperature variation. However, only the constant temperature case was carried through in the element formulation. This investigation explore the effects of spatial temperature variation in the axial and through-the-thickness direction of this proposed element and present a new standard three-node beam finite element modified for structure constructed of FGMs. Also, the influence of the temperature dependency of the thermo-elastic material properties on the thermal stresses distribution was studied. In addition, variations in the layer thicknesses within multilayer beam models were studied to determine the effect on stresses and factor of safety. Finally, based on the specific factor of safety, which combines together the strength and mass of the beam, the best layer thicknesses for the beam models were established. The key contributions expected from this research are: 1. development and implementation of a three-node beam element as a finite element code into the commercial computational tool MATLAB® to analyze thermo-mechanical stresses in structures constructed of functionally graded materials; 2. a strategy to simulate different load cases in structures constructed of functionally graded materials; 3. an analysis of the influence of the FGM interlayer thickness on the factor of safety/specific gravity ratio in structures constructed of functionally graded materials under thermo-mechanical loads; 4. and an analysis/comparison of the advantages/benefits of using structures constructed of functionally graded materials with respect to those constructed with homogenous materials.

Este trabalho estuda a transferência de calor por condução considerando a condutividade térmica como uma função constante por partes da temperatura. Esta relação, embora fisicamente mais realista que supor a condutividade térmica constante, permite obter uma forma explícita bem simples para a inversa da Transformada de Kirchhoff (empregada para tratar a não linearidade do problema). Como exemplo, apresenta-se uma solução exata para um problema com simetria esférica. Em seguida, propôe-se uma formulação variacional (com unicidade demonstrada) que introduz um funcional cuja minimização é equivalente à solução do problema na forma forte. Finalmente compara-se uma solução exata obtida pela inversa da Transformada de Kirchhoff com a solução obtida via formulação variacional. / This work studies conduction heat transfer considering thermal conductivity as a piecewise constant function of temperature. This relationship, although physically more realistic than assuming constant thermal conductivity, provides a simple explicit form for the inverse of Kirchhoff transformation (employed to deal with the problem non-linearity). An exact solution for a problem with spherical symmetry is presented, as an example. In the sequence, a variational formulation (with demonstrated uniqueness) is proposed. This formulation introduces a functional whose minimization is equivalent to the solution of the problem in the strong form. Finally an exact solution obtained using the inverse of Kirchhoff transformation is compared with the solution obtained via variational formulation.

Este trabalho estuda a transferência de calor por condução considerando a condutividade térmica como uma função constante por partes da temperatura. Esta relação, embora fisicamente mais realista que supor a condutividade térmica constante, permite obter uma forma explícita bem simples para a inversa da Transformada de Kirchhoff (empregada para tratar a não linearidade do problema). Como exemplo, apresenta-se uma solução exata para um problema com simetria esférica. Em seguida, propôe-se uma formulação variacional (com unicidade demonstrada) que introduz um funcional cuja minimização é equivalente à solução do problema na forma forte. Finalmente compara-se uma solução exata obtida pela inversa da Transformada de Kirchhoff com a solução obtida via formulação variacional. / This work studies conduction heat transfer considering thermal conductivity as a piecewise constant function of temperature. This relationship, although physically more realistic than assuming constant thermal conductivity, provides a simple explicit form for the inverse of Kirchhoff transformation (employed to deal with the problem non-linearity). An exact solution for a problem with spherical symmetry is presented, as an example. In the sequence, a variational formulation (with demonstrated uniqueness) is proposed. This formulation introduces a functional whose minimization is equivalent to the solution of the problem in the strong form. Finally an exact solution obtained using the inverse of Kirchhoff transformation is compared with the solution obtained via variational formulation.

Polymers capable of thermally controlled reversible bonding reactions are promising candidates for stimuli responsive materials, as required for self-healing or drug delivery materials. In order to investigate how the dynamic reactions can be controlled, effective analytical tools are demanded that are capable of analyzing not only the polymers but can also monitor the respective bonding reactions. Herein, we employ size exclusion chromatography in a newly developed temperature dependent mode (TD SEC) for the in situ characterization of polymers that undergo retro Diels-Alder (rDA) reaction at temperatures higher than 60 °C. Monitoring the evolution of the molar mass distribution of the polymers during the rDA reaction and evaluating the data quantitatively gives detailed information about the extent of the reaction and allows elucidating structural parameters that can be used for controlling the polymers debonding behavior. In contrast to spectroscopic techniques, TD SEC analyzes only the size of the polymers, hence the polymers do not need to fulfill any particular requirements (e.g. presence of detectable functional groups) but only need to be soluble in the TD SEC, which makes the method universally applicable. Side effects that might bias the results are minimized by using a high temperature chromatograph that allows performing the analysis in a broad temperature range (60 – 200 °C) and in different solvents. Thus, the analysis can be performed under the exact conditions that are required for the bonding reactions and an in situ image is provided.

The COSC-1 borehole located in the Lower Seve nappe of the Central Scandinavian Caledonides is intended to study the tectonic evolution of the Paleozoic orogen. The drilling project reached a depth of 2495.8m and obtained samples from different lithologal units of mica schist, amphibolite, gneiss, and mylonitic gneisses.     To test if the samples are suitable for paleomagnetism, laboratory measurements of natural remanent magnetism are performed on sub-samples of the COSC-1 drill core in the paleomagnetic laboratory with alternating field demagnetization, IRM acquisition as well as the temperature dependence of susceptibility measurements. Important properties of the samples such as coercivity, Curie temperature, inclination, and declination are determined with the measurements.     Most of the samples carry a remanent magnetization that can be readily demagnetized with alternating field demagnetization up to 100 mT. Some of the samples may be suitable for paleomagnetism, with the major ferromagnetic mineral compositions of magnetite, hematite, and FeTi oxides. However, low coercivities and median destructive fields suggest that the magnetite-bearing samples will be prone to remagnetization, making them more challenging to use in terms of retrieving a primary magnetization originating from the Caledonian orogeny. The thermomagnetic results of some samples reflect the metamorphic conditions experienced by the rocks and the mineral assemblage changed irreversibly during step-wise heating experiments. These results can possibly be used as an indicator for the metamorphic temperature experienced by the different lithologal units. Although further measurements are needed to get a clearer understanding of the suitability of the COSC-1 sample for paleomagnetic reconstructions (including thermal demagnetization experiments), this thesis indicates that the COSC-1 rocks contain interesting paleo- and rock magnetic features that are worth further study.

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