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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Broadband absolute absorption measurements of atmospheric continua with millimeter wave cavity ringdown spectroscopy

Meshkov, Andrey I. 22 February 2006 (has links)
No description available.
2

An Assessment of Factors Limiting Tropical Congestus Cloud-Top Heights

Casey, Sean P. 2009 December 1900 (has links)
binding of either tyrosine or 6MPH4 alone does not change the coordination. However, when both tyrosine and 6MPH4 are bound, the active site becomes 5-coordinate, creating an open site for reaction with O2. Investigation of the kinetics of oxygen reactivity of TyrH complexes in the absence and presence of tyrosine and/or 6MPH4 indicated that there is a significant enhancement in reactivity in the 5-coordinate complex in comparison to the 6-coordinate form. Similar investigations with E332A TyrH showed that Glu332 residue plays a role in directing the protonation of the bridged complex that forms prior to the formation of Fe(IV)O. Rapid chemical quench analyses of DOPA formation showed a burst of product formation, suggesting a slow product release step. Steady-state viscosity experiments established a diffusional step as being significantly rate-limiting. Further studies with stopped-flow spectroscopy indicated that the rate of TyrH reaction is determined by a combination of a number of physical and chemical steps. Investigation of the NO complexes of TyrH by means of optical absorption, electron paramagnetic resonance (EPR) and electron spin echo envelope modulation (ESEEM) techniques revealed the relative positions of the substrate and cofactor with respect to NO, an O2 mimic, and provided further insight into how the active site is tuned for catalytic reactivity upon substrate and cofactor binding. The second theory is that a decreased vertical temperature lapse rate, dT/dp, would slow cloud growth, creating a mode of cloud-top heights at the stable layer as clouds lose buoyancy. The signal for lapse rate changes in the AIRS data, however, is not as strong as the signal for RH differences. Near 600-400 hPa, roughly the region where congestus cloud-top heights are located, no significant difference in lapse rates is noted between congestus and deep clouds; in fact, the mean values suggest that congestus clouds appear in more unstable atmospheres than deep clouds. Only slight differences in temperature and lapse rate are noted in ERA data as well. These results suggest that drier air may play a greater role in limiting congestus cloud-top heights than increased atmospheric stability. Five years of relative humidity (RH) observations from the Atmospheric Infrared Sounder (AIRS) instrument aboard the Aqua satellite are then analyzed to identify areas of anomalously dry air between 600 and 400 hPa over deep convective regions of the tropical oceans. Back trajectories are then calculated for each observed parcel.
3

The role of the Mexican Plateau in shaping rainfall over Texas

Ren, Tong 17 February 2014 (has links)
Previous studies have suggested that advection from the Mexican Plateau (MP) may influence rainfall over Texas in spring and summer; generally air ascends over the cordillera and descends over the southern plains. The two mechanisms may link the northern Mexico drought to Texas drought. Observations and the Community Earth System Model are used in this study to describe the 2011 Texas-northern-Mexico drought and examine the role of the MP on the hydro-climate over the southern US, providing implications for the linkage between the MP and rainfall over Texas. A control run and three experimental runs were performed with prescribed sea surface temperatures and sea ice fractions. The results show that when the MP becomes dry, rainfall declines locally and downstream. During the spring, the dry air brought to Texas by prevailing westerly winds suppresses local convection; but dry air advection from the highlands has little influence on rainfall over Texas during the summer when Texas is no longer in the downstream areas. During the summer, a warmer MP draws moist air over the peripheral low elevation areas to the highlands; it bends the low-level jet towards the highlands and an anti-cyclonic flow anomaly forms over the southern US, which causes air to diverge and tends to reduce rainfall over the southern US. / text
4

Konstrukční návrh průmyslové sušárny / Design of industrial drying

Junek, Jan January 2013 (has links)
This thesis deals with the constructional design of the industry dryer meant for the production of the current and voltage transformers of the KPB Intra s.r.o. company. The basic theory of the drying and the heat balance of the dryer are processed in this thesis, and also the brief overview of the constructional solutions of the industry dryers and their usage. In detail it focuses on the constructional possibilities of the chosen dryer for the given application. Essential parts of the thesis are the constructional calculations for the power determination of the ventilator, heating units, condensational units, the exchanger, engine with transmission and the calculations for the mechanism dimensioning of the shelf adjusting, clamping case and the springs for the chain stretching. Last but not least it consists of the technical-economical evaluation of the suggested solution and its risk analysis. Drawing documentation, 3D model and the animation of its moving components form also the part of this thesis.
5

Thermodynamic properties of humid air and their application in advanced power generation cycles

Ji, Xiaoyan January 2006 (has links)
Water or steam is added into the working fluid (often air) in gas turbines to improve the performance of gas turbine cycles. A typical application is the humidified gas turbine that has the potential to give high efficiencies, high specific power output, low emissions and low specific investment. A heat recovery system is integrated in the cycle with a humidifier for moisturizing the high-pressure air from the compressor as a kernel. Based on today’s gas turbines, the operating temperature and pressure in the humidifier are up to about 523 K and 40 bar, respectively. The operating temperature of the heat exchanger after the humidifier is up to 1773 K. The technology of water or steam addition is also used in the process of compressed air energy storage (CAES), and the operating pressure is up to 150 bar. Reliable thermodynamic properties of humid air are crucial for the process simulation and the traceable performance tests of turbomachinery and heat exchanger in the cycles. Several models have been proposed. However, the application range is limited to 400 K and 100 bar because of the limited experimental data for humid air. It is necessary to investigate the thermodynamic properties of humid air at elevated temperatures and pressures to fill in the knowledge gap. In this thesis, a new model is proposed based on the modified Redlich-Kwong equation of state in which a new cross interaction parameter between molecular oxygen and water is obtained from the fitting of the experimental data of oxygen-water system. The liquid phase is assumed to follow Henry’s law to calculate the saturated composition. The results of the new model are verified by the experimental data of nitrogen-water and oxygen-water systems from ambient temperature and pressure to 523 K and 200 bar, respectively. Properties of air-water system are predicted without any additional parameter and compared with the available experimental data to demonstrate the reliability of the new model for air-water system. The results of air-water system predicted using the new model are compared with those calculated using other real models. The comparison reveals that the new model has the same calculation accuracy as the best available model but can be used to a wider temperature and pressure range. The results of the new model are also compared with those of the ideal model and the ideal mixing model from ambient temperature and pressure to 1773 K and 200 bar to investigate the effect of the models on the thermodynamic properties of humid air. To investigate the impact of thermodynamic properties on the simulation of systems and their components, different models (ideal model, ideal mixing model and two real models) are used to calculate the thermodynamic properties of humid air in the simulation of the compressor, humidification tower, and heat exchanger in a humidified gas turbine cycle. The simulation reveals that a careful selection of a thermodynamic property model is crucial for the cycle design. The simulation results provide a useful tool for predicting the performance of the system and designing the humidified cycle components and systems. / QC 20100902
6

Charakterizace dielektrických bariérových výbojů za atmosférického tlaku / Characterization of dielectric barrier discharges at atmospheric pressure

Budík, Martin January 2011 (has links)
The aim of this dissertation is to get to know metodology and construction of suitable electrical insertion in measurement of energy consumed by discharge. These findings will serve to scale dependings of output to frequence for surface and voluminous dielektric barrier discharge in synthetic dry air and determination of effect of humidity in air on electric characteristics of discharge.

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