Os alginatos de metais alcalinos (Li+, Na+ e K+), alcalino-terrosos (Mg2+, Ca2+, Sr2+ e Ba2+), de amônio, mono-, di- e trietanolamônio foram sintetizados por neutralização do ácido algínico com os respectivos hidróxidos, ou carbonatos, e com as aminas. Os sais foram caracterizados por análise elementar e espectroscopia na região do infravermelho, confirmando as sínteses. Após caracterização, os compostos foram submetidos à análise térmica (TG/DTG, DTA e DSC) para avaliar seu comportamento térmico e seus resíduos de decomposição, que foram caracterizados por IR e XRD. Os alginatos de amônio e etanolamônio se decompuseram com liberação de amônia ao final do experimento. Os alginatos de metais alcalinos foram convertidos nos seus respectivos carbonatos, enquanto os alginatos de metais alcalino-terrosos se decompuseram formando carbonatos, em seguida óxidos. Foi feita uma avaliação de procedimentos de secagem por estufa a vácuo a 40 ºC e liofilização; e o último método mostrou-se mais eficaz. A água residual, não-congelável, sai associada à decomposição do material e não foi possível definir exatamente seu teor. Um método de medir o grau de substituição nos sais das aminas foi desenvolvido com base em 13C ? NMR em fase sólida. / The alkaline (Li+, Na+ and K+), earth-alkaline (Mg2+, Ca2+, Sr2+ and Ba2+), ammonium, mono-, di- and triethanolammonium alginic acid salts were obtained from the neutralization reaction between alginic acid and the respective hydroxides or carbonates, and the amines, The salts were characterized by elemental analysis and infrared spectroscopy, confirming the synthesis. After the characterization, the compounds were submitted to thermal analysis (TG/DTG, DTA and DSC), in order to evaluate their thermal behavior. The thermal decomposition residues were characterized by IR and/or XRD. The NH4+ and ethanolammonium alginates decomposed via NH3 release without residue in the crucible at the end of the experiment. The alkaline alginates were converted to the respective carbonates, and the earth-alkaline decomposed with production of the carbonates followed by convertion to the oxides. An evaluation of drying procedures involving heating under vaccum up to 40°C and lyophilization were performed, pointing better results in the last case. The residual water, of the non-freezing type, was completely released only during the decomposition of the biopolymer, and it was not possible to define its exact content in the samples. An attempt to estimate the substitution degree in the ethanolammonium salts using 13C ? NMR data, in solid state, was also described.

The kinetic study of thermal decomposition of compounds (A)-(E) had been examined. The thermal decomposition product of 1,1-dimethyl-5-(1-isobutenyl)-1-pyrazoline is 1,1-dimethyl5-(1-isobutenyl)cyclopropane, no hydrogen transfer or rearrangement was occured. The only isolated thermal decomposition product of 3-methyl-3,4-dicarboxylic anhydride-l-pyrazoline was dirnethylmaleic anhydride. Since carbon dioxide was found in the decomposition process and the amount of nitrogen gas and carbon dioxide was not the same, it indicated that the decarboxylation product was not come from the nitrogen freed anhydride product.Ball State UniversityMuncie, IN 47306

No description available.

Thesis (M.S.)--Ohio University, August, 2009. / Title from PDF t.p. Includes bibliographical references.

This thesis details a three dimensional model for simulating the operation of two particular configurations of a lithium iron phosphate (LiFePO¬4) battery. Large-scale lithium iron phosphate batteries are becoming increasingly important in a world that demands portable energy that is high in both power and energy density, particularly for hybrid and electric vehicles. Understanding how batteries of this type operate is important for the design, optimization, and control of their performance, safety and durability. While 1D approximations may be sufficient for small scale or single cell batteries, these approximations are limited when scaled up to larger batteries, where significant three dimensional gradients might develop including lithium ion concentration, temperature, current density and voltage gradients. This model is able to account for all of these gradients in three dimensions by coupling an electrochemical model with a thermal model. This coupling shows how electrochemical performance affects temperature distribution and to a lesser extent how temperature affects electrochemical performance. This model is applicable to two battery configurations — spirally wound and prismatically wound. Results generated include temperature influences on current distribution and vice versa, an exploration of various cooling environments’ effects on performance, design optimization of current collector thickness and current collector tab placement, and an analysis of lithium plating risk. / text

Assessing hazards due to energetic or reactive chemicals is a challenging and complicated task and has received considerable attention from industry and regulatory bodies. Thermal analysis techniques, such as Differential Scanning Calorimeter (DSC), are commonly employed to evaluate reactivity hazards. A simple classification based on energy of reaction (-H), a thermodynamic parameter, and onset temperature (To), a kinetic parameter, is proposed with the aim of recognizing more hazardous compositions. The utility of other DSC parameters in predicting explosive properties is discussed. Calorimetric measurements to determine reactivity can be resource consuming, so computational methods to predict reactivity hazards present an attractive option. Molecular modeling techniques were employed to gain information at the molecular scale to predict calorimetric data. Molecular descriptors, calculated at density functional level of theory, were correlated with DSC data for mono nitro compounds applying Quantitative Structure Property Relationships (QSPR) and yielded reasonable predictions. Such correlations can be incorporated into a software program for apriori prediction of potential reactivity hazards. Estimations of potential hazards can greatly help to focus attention on more hazardous substances, such as hydroxylamine (HA), which was involved in two major industrial incidents in the past four years. A detailed discussion of HA investigation is presented.

Chip temperature is increasing with continued technology scaling due to increased power density and decreased device feature sizes. Since temperature has significant impact on performance and reliability, accurate thermal and circuit analysis are of great importance. Due to the shrinking device feature size, effects occurring at the nanometre scale, such as ballistic transport of energy carriers and electron tunneling, have become increasingly important and must be considered. However, many existing thermal and circuit analysis methods are not able to consider these effects efficiently, if at all. This thesis presents methods for accurate and efficient multi-scale thermal and circuit analysis. For circuit analysis, the simulation of single-electron device circuits is specifically studied. To target thermal analysis, in this work, ThermalScope, a multi-scale thermal analysis method for nanometre-scale IC design is developed. It unifies microscopic and macroscopic thermal physics modeling methods, i.e., the Boltzmann transport and Fourier modeling methods. Moreover, it supports adaptive multi-resolution modeling. Together, these ideas enable efficient and accurate characterization of nanometre-scale heat transport as well as chip-package level heat flow. ThermalScope is designed for full chip thermal analysis of billion-transistor nanometre-scale IC designs, with accuracy at the scale of individual devices. ThermalScope has been implemented in software and used for full chip thermal analysis and temperature-dependent leakage analysis of an IC design with more than 150 million transistors. To target circuit analysis, in this work, SEMSIM, a multi-scale single-electron device simulator is developed with an adaptive simulation technique based on the Monte Carlo method. This technique significantly improves the time efficiency while maintaining accuracy for single-electron device and circuit simulation. It is shown that it is possible to reduce simulation time up to nearly 40 times and maintain an average propagation delay error of under 5% compared to a non-adaptive Monte Carlo method. This simulator has been used to handle large circuit benchmarks with more than 6000 junctions, showing efficiency comparable to SPICE, with much better accuracy. In addition, the simulator can characterize important secondary effects including cotunneling and Cooper pair tunneling, which are critical for device research. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2008-09-26 13:33:12.389

No description available.

This thesis describes the thermal design and thermal testing of the development model radiative cooler for the Composite Infra-Red Spectrometer (CIRS) due for launch on the Cassini spacecraft in 1997. The radiative cooler is used to cool the instrument's Focal Plane Assembly (FPA) to approximately 80K. The FPA holds two arrays of HgCdTe detectors for the mid infra-red spectrometer of the instrument which covers the wavelength range 7μm to 17μm. The FPA is mounted from the optics on a titanium alloy tripod and is cooled conductively by the radiator via a flexible link and a cold finger. A range of thermal models of the system have been developed ranging from a simple, analytical model to a finite difference numerical model. A calorimeter was designed to perform heat leak measurements on samples of Multi- Layer Insulation (MLI) blankets to determine the number and type of shields required for the MLI blanket covering the back of the cooler radiator. A test facility incorporating a vacuum system, a space simulator target, and a simulator for the CIRS instrument was designed and constructed for testing the assembled cooler. Various configurations of the Development Model (DM) CIRS cooler were tested as components became available and the results obtained compared to the thermal model predictions. It was found that the cooler will attain a temperature of 80K in operation, but with less excess cooling power than predicted by the thermal models.

Thesis (Ph.D.)--Tufts University, 2002. / Adviser: Peggy Cebe. Submitted to the Dept. of Physics. Includes bibliographical references. Access restricted to members of the Tufts University community. Also available via the World Wide Web;