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A large amount of heat can be liberated during cement hydration, causing very large temperature increases in mass concrete members. The non-uniform temperature field produced by the cement during curing can cause very high internal stresses that may crack the concrete. Concrete thermal cracking in very large structures is a well-known phenomenon and was studied extensively during the height of dam construction in the United States. In recent years concrete bridge member sizes have increased for structural and aesthetic reasons. Recent problems in San Antonio and Houston, Texas with thermal cracking and very high internal temperatures in mass concrete bridge members has renewed interest in studying early-age thermal cracking and its mechanisms. In order to predict the early-age thermal cracking risk of a concrete member, the temperature history, autogenous shrinkage, modulus development, tensile strength development, coefficient of thermal expansion development, creep behavior, and external restraint conditions must be known. A testing procedure has been developed to measure concrete heat of hydration, mechanical property development, and free shrinkage response at different curing temperatures. The concrete free shrinkage includes thermal and autogenous shrinkage components and is measured using a newly developed free shrinkage testing apparatus. The early age concrete creep is calculated from rigid cracking frame tests performed at different varying temperatures. Trends in early age creep behavior for different concrete mixtures common in mass concrete have been found and are used to develop a statistical model relating concrete mixture proportions and constituent material properties for use in mass concrete thermal stress modeling. The results from the test methods described are used in a new concrete early-age cracking risk and durability software package called ConcreteWorks. / text

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This thesis is about problematics of creating Computational Fluid Dynamics (CFD) model suited for analysis of airflow around sitting passive person. Thesis includes analysis of velocity field distribution, thermal distribution and thermal losses in the surroundings of sitting thermal dummy (computational model) and comparison of these values with experimental measurements. Thesis is a part of large experimental research (this research is not included here) focused on creating of functional method used for person-surrounding airflow analysis in future commercial use.

We present a periodic technique for measuring the thermal conductivity and diffusivity of thin samples simultaneously. In samples of this type, temperature measurements must be made across the sample faces and are therefore subject to large error due to the interface resistance between the temperature sensor and the sample. The technique uses measurements of the amplitude and phase of the periodic temperature across both a reference sample and the unknown material at several different frequencies. Modeling of the heat flow in the sample allows the simultaneous determination of the thermal parameters of the sample as well as the interface resistance. Data will be presented for standard materials to show the viability of the technique.

Wang, Ranshi = 透明电解质/氧化锌异质结热稳定性的研究 / 王然石. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 130-134). / Abstracts in English and Chinese. / Wang, Ranshi = Tou ming dian jie zhi/yang hua xin yi zhi jie re wen ding xing de yan jiu / Wang Ranshi. / Chapter I. --- Abstract / Chapter II. --- Acknowledgement / Chapter III. --- Table of contents / Chapter IV. --- List of figures / Chapter V. --- List of tables / Chapter 1 --- Introduction / Chapter 1.1 --- Motivations / Chapter 1.2 --- Outline of thesis / Chapter 2 --- Experimental Conditions and Techniques Used / Chapter 2.1 --- Sample preparation / Chapter 2.1.1 --- Radio frequency magnetic sputtering / Chapter 2.1.2 --- ITO glass / Chapter 2.1.3 --- Thermal evaporation / Chapter 2.1.4 --- Thermal annealing / Chapter 2.2 --- Optical characterization of ZnO / Chapter 2.2.1 --- Photoluminescence (PL) measurement / Chapter 2.2.2 --- SEM and cathodoluminescence spectroscopy / Chapter 2.3 --- Time-of-FIight Secondary Ion Mass Spectroscopy (TOF-SIMS ) / Chapter 2.4 --- Electrical measurements / Chapter 3 --- Calibrations / Chapter 3.1 --- Sample Thickness / Chapter 3.2 --- Calibrations of cathodeluminescence measurements / Chapter 3.2.1 --- Probe current and specimen current / Chapter 3.2.2 --- Sample uniformity in CL measurement / Chapter 3.2.3 --- Mirror position / Chapter 3.2.4 --- Non-linear relation between CL emission and current / Chapter 3.2.5 --- CL band-edge emission stability / Chapter 3.2.6 --- Effect of magnification / Chapter 3.2.7 --- Effect of electron beam shift / Chapter 3.2.8 --- Conclusions / Chapter 3.3 --- C-V measurement / Chapter 4 --- Experimental Results and Data Analysis / Chapter 4.1 --- Optical properties / Chapter 4.1.1 --- Luminescence of ZnO / Chapter 4.1.2 --- Light emitting thermal stability of A10x (MgO) capped ZnO film / Chapter 4.1.2.1 --- Emission degradations in annealing treatment by PL / Chapter 4.1.2.2 --- Evidence about the interface degradation / Chapter 4.1.2.3 --- CL studies of the emission from sample surface / Chapter 4.2 --- Secondary Ion Mass Spectroscopy (SIMS) studies of AIOx-capped ZnO / Chapter 4.2.1 --- Data processing / Chapter 4.2.2 --- Diffusion width / Chapter 4.3 --- Simulation of Zn out diffusion to the dielectric layer / Chapter 4.3.1 --- Structure and assumptions / Chapter 4.3.2 --- Calculations of diffusion by Fick's Law / Chapter 4.3.3 --- Simulation of PL reduction from diffusion / Chapter 4.3.4 --- Short-time PL / Chapter 4.4 --- Simulation of defects generation in emission reduction process / Chapter 4.4.1 --- Some calculations of continuity equation / Chapter 4.4.2 --- First order equation for defect generation / Chapter 4.5 --- Electrical measurements / Chapter 4.5.1 --- Theory of C-V measurement for MOS structure / Chapter 4.5.1.1 --- MOS Structure / Chapter 4.5.1.2 --- Discussions about surface charge and energy level in C-V experiments of MOS / Chapter 4.5.1.3 --- Useful formulations / Chapter 4.5.2 --- Experimental results of C-V and parameter extraction / Chapter 4.5.2.1 --- Effect of series resistance correction / Chapter 4.5.2.2 --- Effect of thermal annealing to C-V curves on dielectric/ZnO/ITO / Chapter 4.5.2.3 --- Doping concentration (ND) / Chapter 4.5.2.4 --- Discussion about the fixed and mobile charge / Chapter 4.5.3 --- Simulation of C-V relation in dielectric/ZnO / Chapter 4.5.4 --- Current-voltage (I-V) measurements / Chapter 4.5.5 --- Conductance-voltage measurements (G-V) and interface trap density / Chapter 4.5.6 --- DLTS measurements for extracting interface trap density / Chapter 5 --- Discussions and Conclusion / Chapter 5.1 --- Mechanism / Chapter 5.2 --- Conclusions / Chapter 5.3 --- Future plan / Chapter 6 --- References

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Buildings consume more than 30 percent of the primary energy worldwide with 65 percent of this attributed to heating ventilation and cooling. To help address this, stratified concrete panels (SCP) have been developed to provide insulation without compromising the thermal mass of concrete. SCP is created by vibrating a single concrete mix containing heavy and lightweight aggregates. Vibration causes the heavy aggregates drop to the bottom so that two distinct strata are formed; an internal structural/heavyweight layer providing thermal mass and an external lightweight layer for insulation. SCP incorporates waste products, for both financial and environmental gains, from which technical benefits also result. Stratified concrete panels have been made and tested during past research projects with results suggesting that SCP could be a competitive product in the residential construction industry, an area in which precast concrete systems have not been favoured in New Zealand. Consideration has been given to the specific rheological requirements of the concrete mix design and the hardened properties of the finished panels. This research considers the commercial viability of SCP using an industrial setting. For practicality of the setting, some materials were altered from past laboratory work to materials that are more easily sourced and better understood but with similar properties as those used previously. Several panels were cast at Stahlton precast yard in an effort to optimise the production process. Consistent results were not achieved and a range of stratification levels were produced. This showed that some capital investment is required to commercialise SCP to provide more energy for vibration such that sufficient stratification can be reliably attained. Two panels were then stood up in an exposed area with the exterior facing north to test for warping effects in a practical setting. No measurable warping occurred over this time which concurred with past work and long term readings that were taken of four year old panels. Structural, thermal and durability tests were carried out on panels with a range of stratification levels to assess the sensitivity of these properties to the level of stratification. From this it was found that the panels with better stratification had significantly better thermal properties than those with moderate to poor stratification. Generally the thermal targets for this project were not met with the total thermal resistance (R-values) not meeting current code requirements. In some cases structural properties were improved with better stratification as the structural layer was stronger through better consolidation. Delamination potential increased with stratification and with age. This requires further research to minimise this effect using fibres across the layer boundary. Porosity was increased in the structural layer in the poorly to moderately stratified panels as the structural layer was not consolidated enough due to lightweight aggregate contamination. As with any new innovation, market acceptance is largely governed by public perception. With appropriate marketing as a sustainable energy saving product, SCP has the potential to be competitive in the residential construction market with some capital investment.