A gas-fluidized bed bioreactor was developed in this research as a new method for treating polluted air. The fluidization characteristics of selected packing materials were investigated. Then, bioremediation was tested using two types of packing in a fluidized bioreactor, as well as in a comparable packed bed. Microorganisms on the particles biodegrade contaminants in the polluted air, which flows up through the bed. At high flowrates, the polluted air fluidizes the particles, while at low velocities the operation is in packed bed mode.<p>Initially, sawdust was selected for use as a packing material. Due to the poor fluidization properties of sawdust, glass spheres were added. A mixture of sawdust and glass spheres remained well mixed during fluidization. In the mixture, interparticle forces increased with increasing moisture in the sawdust, eventually causing defluidization of the bed. In the absence of bioremediation, mass transfer was studied between ethanol-contaminated air and sawdust/glass sphere packing, and found to be higher in the fluidized versus packed mode. In bioremediation experiments, ethanol removal efficiencies were as high as 95% in both operating modes. The maximum elimination capacities (EC) of ethanol were 75 and 225 g m^-3 sawdust h^-1 in the fluidized and packed beds respectively.<p>The packing of the fluidized bed bioreactor was optimized in order to boost bioremediation rates. Experiments showed that peat granules fluidized well in a bubbling regime, likely due to their relatively high density and sphericity. In peat bioremediation trials, the fluidized mode outperformed the packed bed; the maximum ECs were 1520 and 530 g m^-3 peat h^-1, respectively. Removal efficiency in the fluidized mode decreased with velocity, because the size and amount of large bubbles increased.<p>A steady-state model of the fluidized bioreactor was developed. By taking account of bubble properties during fluidization, the model helps to explain how bubble size, microbial properties and bioreactor residence time affect removal efficiency and elimination capacity of the bioreactor.<p>A peat gas-fluidized bioreactor shows promise as an efficient, low-cost technology for air treatment. Particle mixing in the fluidized bed may prevent operating problems associated with the packed bed bioreactor. Fluidized bioreactors are ideal for the treatment of high volume, low concentration air emissions.

This research lays a foundation for automated acquisition of volatile data by presenting a prototype device which carries out the deeds of a forensic investigator, essentially making it a “forensic investigator on a stick”. The Teensy 3.0 device is programmed to interact with an external USB device for storage purposes. All interaction with a live target system must be documented thoroughly according to forensic best practices. Therefore quantitative measurements of system contamination related to the device actions are presented. The device is conclusively able to perform a memory dump and provide a warning of the existence of Truecrypt encrypted containers.

Anaerobic digestion is a common process for treatment of wastewater sludge from municipal sewage systems. Volatile sulfur compounds, including volatile organic sulfur compounds (VOSCs) and hydrogen sulfide, have been reported as the most odorous compounds in digestion emissions and impurities which can damage facilities for generation, transportation, storage, and utilization of biogas. There has been no comprehensive study on biological generation and degradation kinetics of VOSC or modeling VOSC behaviors through anaerobic sludge digestion. The goal of the present study was to establish a model for VOSC conversions in anaerobic sludge digestion which could facilitate quantitative analysis of VOSC emissions in anaerobic digestion. VOSCs and methionine were employed in dosed batch tests. VOSC conversion processes in anaerobic methionine digestion have been identified. The kinetics for the identified VOSC degradation and conversion processes were determined at 35 and 55 °C respectively. Mixed-second order kinetics were found to best fit the conversion processes. A model was established based on the identified processes and estimated kinetic constants. To extend the model to VOSC release in anaerobic sludge digestion, mesophilic and thermophilic incubations were conducted with four different sludge samples. The effects of temperature and sludge source on VOSC release patterns were assessed. It was found that an unidentified DMS generation mechanism was triggered in the mesophilic incubation of activated sludge in which iron was dosed. To apply the model which was established based on methionine degradation in sludge digestion, hydrolysis of particulate materials was incorporated. The model simulations for VOSC behavior in thermophilic batch incubation were able to represent the observed VOSC releases. However, the simulations could not well fit the observed VOSC release at 35 ° because the model did not include the unidentified DMS generation mechanism. Application of the model to bench-scale digesters was lack-of-fit. It may have been due to imprecise estimation of the degradable sulfur in the feed sludge. In addition, in the batch tests and digester operation the ratios of the raw and digested sludge were different. This might have resulted in different concentrations of the microorganisms which mediated biotransformations and hence resulted in different kinetic constants.

A gas-fluidized bed bioreactor was developed in this research as a new method for treating polluted air. The fluidization characteristics of selected packing materials were investigated. Then, bioremediation was tested using two types of packing in a fluidized bioreactor, as well as in a comparable packed bed. Microorganisms on the particles biodegrade contaminants in the polluted air, which flows up through the bed. At high flowrates, the polluted air fluidizes the particles, while at low velocities the operation is in packed bed mode.<p>Initially, sawdust was selected for use as a packing material. Due to the poor fluidization properties of sawdust, glass spheres were added. A mixture of sawdust and glass spheres remained well mixed during fluidization. In the mixture, interparticle forces increased with increasing moisture in the sawdust, eventually causing defluidization of the bed. In the absence of bioremediation, mass transfer was studied between ethanol-contaminated air and sawdust/glass sphere packing, and found to be higher in the fluidized versus packed mode. In bioremediation experiments, ethanol removal efficiencies were as high as 95% in both operating modes. The maximum elimination capacities (EC) of ethanol were 75 and 225 g m^-3 sawdust h^-1 in the fluidized and packed beds respectively.<p>The packing of the fluidized bed bioreactor was optimized in order to boost bioremediation rates. Experiments showed that peat granules fluidized well in a bubbling regime, likely due to their relatively high density and sphericity. In peat bioremediation trials, the fluidized mode outperformed the packed bed; the maximum ECs were 1520 and 530 g m^-3 peat h^-1, respectively. Removal efficiency in the fluidized mode decreased with velocity, because the size and amount of large bubbles increased.<p>A steady-state model of the fluidized bioreactor was developed. By taking account of bubble properties during fluidization, the model helps to explain how bubble size, microbial properties and bioreactor residence time affect removal efficiency and elimination capacity of the bioreactor.<p>A peat gas-fluidized bioreactor shows promise as an efficient, low-cost technology for air treatment. Particle mixing in the fluidized bed may prevent operating problems associated with the packed bed bioreactor. Fluidized bioreactors are ideal for the treatment of high volume, low concentration air emissions.

Non-volatile memory is slower than DRAM (Dynamic Random Access Memory) but faster than HDD (Hard Disk Drive). In addition, compared to volatile memory, the non-volatile memory can retain stored information without power, and consume only low power. These characteristics show its popularity of flash memory built in portable devices. Currently the non-volatile memory applies the polysilicon and SONOS structure as floating gate, however, the new technologies of nanocrystal non-volatile memory are processed at high temperature. The manufacturing cost is rather high, so the process at lower temperature is very necessary. In this work, mixed zinc and silica amorphous layers are applied as floating gate to construct nano thin film non-volatile memory devices. The process does not need high temperature to form crystalline, and the defects in zinc oxide can be applied for charge storage. Supercritical carbon dioxide (SCCO2) treatment has been studied for the passivation of dielectric and reducing the activation energy. Using this low-temperature SCCD process ZnO nanocrystal can be formed, and the feasibility of fabricating nanocrystal NVMs device with low temperature SCCO2 is possible. The nonvolatile memory devices with Zn nano thin film embedded in MIS structure are performed. From C-V measurement, it is found that defects in SiO2 are repaired after 500¢J annealing. Because of the thermal diffusion, the storage layer SiO2/Zn-SiO2/SiO2 in device cannot be observed and the memory window disappears when the annealing temperature is higher than 700¢J. Therefore, the annealing process should be performed between 500¢J - 700¢J in making memory device. From DLTS analysis, a species with energy level of 0.6 eV is found in the as deposited Zn-SiO2 layer. After annealing in Ar, a new energy level 0.47 eV is found, and which shifts to energy level 0.85 eV after annealing in O2. In comparison to XPS results, traps of Zn-SiO2 exist before annealing, and after annealing in Ar, Zn-SiO2 transforms into Zn-O-Si. Traps of ZnO-SiO2 have been found after annealing in O2, which increases the memory effect with a 2 Volt memory window, so that more charges can be stored in the deep level traps of ZnO-SiO2 in the storage layer.

In recent years, due to the rapid development of electronic products, non-volatile memory has become more and more important. However, flash memory has faced some physical limits bottleneck with size scaling-down. In order to overcome this problem, alternative memory technologies have been extensively investigated, including ferroelectric random access memory (FeRAM), magneto resistive RAM (MRAM), phase-change RAM (PRAM), and resistive RAM (RRAM). All of this potential next generation non-volatile memory, the resistive random access memory has most advantages such as simple structure, lower consumption of energy, lower operating voltage, high operating speed, high storage time and non-destructive access, which make it be the most potential candidate of the next generation non-volatile memory. Many studies have proposed to explain the resistance switching phenomenon, which is due to the metallic filament or the oxygen vacancies. Therefore, in order to investigate the influence of resistance switching characteristic by metal or oxygen, we choose the non-metal contained boron oxy-nitride film as the insulator layer and successfully make the resistance has the switchable characteristic of this device. Furthermore, we improved the iv stability by using the Gadolinium-doped method in the boron oxy-nitride based film. In addition, we observed the negative current differential phenomenon during the set process, which can further controlled by lower operating voltage to achieve the interfacial resistance switching. We think that is due to the formation of nitrogen titanium oxide at the interface between insulator layer and titanium nitride electrode, which caused the Schottky barrier formation and reduced the current flow. In addition, current conduction fitting can also confirm this hypothesis. Besides, titanium nitride easily bond with oxygen ions; moreover, the oxygen ions can be easily disturbed at higher temperature ambient. We believed there may easily form the nitrogen titanium oxide layer in higher temperature environment; which also improve by a series of varied temperature experiments. However, this nitrogen titanium oxide layer formed naturally very easily, resulting in an inevitable problem of data retention time, which wish to be resolved in the future.

The operating characteristics of non-volatile memory for modern requirement are high-density , low power consumption, fast read and write speed, and good reliability. The floating gate memory generated leakage path in the tunnel oxide during the trend of scaling down, which will result in the loss of all stored charge to the silicon substrate. As the data retention time and endurance are taken into consideration, the thickness of tunnel oxide exist a physical limit, owing to the demand of high-density capacities. RRAM is offered as an option in the next generation non-volatile memories, due to the following advantages: (1) simple structure and easy to process, and low cost ; (2) less restrictive in the scaling-down process; (3) with the multi-bit data storage features; (4) high speed operation; (5) Repeat write and read is more than one million. In the thesis, we use a simple and low-temperature process to form the silicon germanium oxide (Si-Ge-O) RRAM and silicon germanium oxide RRAM with nitrogen doping between the electrode and silicon-germanium oxide interface. By sputtering at argon and oxygen (Ar/O2), and sputtering at argon and ammonia (Ar/NH3) with silicon-germanium target to form silicon germanium oxide RRAM and silicon germanium oxide (Si-Ge-O)/silicon germanium oxnitride (Si-Ge-O-N) RRAM. By informing a SiGeON layer between the interface of electrode and silicon-germanium oxide improve the stability of write voltage and endurance reliability. In addition, both silicon and germanium are useful as materials in the optoelectronics industry and extensively studied in material science. Based on the two materials, the smiting characterizations of RRAM will be improved in the read-write stability and operation reliability.

Closed-vessel microwave assisted volatilization of Ge, Se, Si and quartz as their volatile compounds , for the determination of trace impurities in high purity Ge, Se, Si and quartz is reported. The volatilization of Ge is 98.7% using vapors of aqua regia whereas vapors generated from 72:1 ratio of HCl:HNO3 is required to volatilize 99.2% of Se. Using vapor of 10:5 ratio of HF:HNO3 , the volatilization of Si is 98.6%, and the volatilization of quartz is 99.0% with 15:3 ratio of the mixed acids. The recoveries of Mg, Cr, Mn,, Ni, Co, Cu, Zn, Cd, Ba and Pb are in the range 83-116%. Determinations are carried out using inductively coupled plasma mass spectrometer with Dynamic Reaction CellTM (DRC ICP-MS). Isobaric interferences, due to the formation of 40Ar12C+, 35Cl16OH+, 40Ar16O+ and 40Ar74Ge+ on the determination of 52Cr+, 56Fe+ and 114Cd+, have been alleviated using ammonia cell gas in DRC. Matrix volatilization using in situ generated acid vapors in closed containers resulted in sub ng mL-1 experimental blanks. Method detection limits are in the low ng g-1 level. The methods developed have been applied to determine trace impurities in high purity Ge, Se, Si and quartz samples.

In this study, a pilot-scale Regenerative Thermal Oxidizer (RTO) was used to test its performance for volatile organic compound (VOC) destruction and degree of thermal energy conservation. The RTO is electrically heated and contains two 0.5 m ¡Ñ 0.5 m ¡Ñ 2.0 m (L ¡Ñ W ¡Ñ H) columns both packed with gravel particles of 1.0 cm in diameter to a height of 1.4 m. The bed has a void fraction of 0.415. The purpose of this study is to establish the influencing operating conditions and to improve the technique for further applications. Experiments include two phases: (1) energy conservation test with no VOC in the influent air stream , and (2) VOC destruction test with influent air streams containing one of the three VOCs: isopropyl alcohol, acetone, and xylene. Phase 1 experiments were conducted in the maximum gravel temperatures (Tmax) of 402-704 oC, superficial gas velocities (Ug, evaluated at ambient temperatures of 25-30 oC) of 0.15-0.50 m/s, and bed shift times (ts) of 0.5-2.0 min. Results indicate that the temperature raise (

We have investigated the chemical sensitivity of nanoporous (NP) alumina-coated surface acoustic wave (SAW) devices that have been surface-modified with polymeric mediating films. The research in this dissertation covers the refinement of the NP alumina coating, development of dendrimer and/or polymer surface modifications, design of composite ultrathin vapor-phase analyte gates, and preparation of selectively permeable, polymeric films that mediate analyte transport. Nanoporous alumina SAW devices were fabricated from planar Al SAW devices using an anodization process that yields a high-surface-area transduction platform. Refinement of the anodization process results in a homogeneously porous substrate capable of ~40 times the analyte sensitivity of conventional planar SAW devices. Attempts to directly impart selective gas-phase analyte permeation with monolayers of amine-terminated, poly(amidoamine) (PAMAM) dendrimer films were investigated with and without secondary functionalization. We also prepared and characterized pore-bridging polymeric composite ultrathin films (~12 nm) of PAMAM dendrimers and poly(maleic anhydride)-c-poly(methyl vinylether) (Gantrez). Access to the underlying pores of the NP alumina coating can be modulated through the sequential deposition of the composite film. These tailorable ultrathin films result in impermeable surface- modifications which fully gate the analyte response without filling the porous structure. Thin spin-cast films (40 nm) of polydimethylsiloxane (PDMS) were developed to simultaneously provide selective sorption and permeation characteristics towards vapor-phase analytes. The porous nature of the underlying alumina coating provides for this real-time evaluation of sorption and permeation. The results suggest that the thin films offer preferential sorption of non-polar organics and selective permeability towards water vapor.