Engineering Commons^™

Processing Of Cds/Cdte Solar Cell And The Growth Model Of Cdte Thin Film, Guogen Liu

Dissertations

Cadmium telluride is the only thin film photovoltaic (PV) technology to surpass crystalline silicon PV in the cost. The most common CdTe solar cells consist of a simple p-n heterojunction structure containing a p-doped CdTe layer and n-doped cadmium sulfide (CdS) layer, which acts as a window layer. Cadmium Sulfide (CdS) thin films are often deposited on glass substrates coated with TCO layers by the close-spaced sublimation (CSS) or sputter techniques in industrial because of in-line production integration. It is seldom reported that CdS is deposited by the chemical bath deposition (CBD) batch process. The bottleneck of CBD for commercial …

Oxidation Kinetics Of Metallic Powders, Hongqi Nie

Dissertations

Aluminum and magnesium are widely used in pyrotechnic formulations and other energetic materials; they are also common components of reactive alloys, e.g., Al-Mg and B-Mg, and others, which are potential fuels for explosives and propellants. Reaction mechanisms and oxidation kinetics of aluminum, magnesium and Al-Mg alloy powders in different oxidizing environments are investigated using thermo-analytical measurements. New methods of data processing are developed, relying on measured particle size distributions of the reactive spherical powders. It became possible to identify the reaction interface location for many heterogeneous metal oxidation processes; for several reactions, detailed kinetic descriptions are obtained.

For aluminum powders, …

Experimental And Modeling Studies In Membrane Distillation, Lin Li

Dissertations

A variety of microporous hydrophobic flat sheet membranes of polyvinylidene fluoride (PVDF) and expanded-polytetrafluoroethylene (e-PTFE) are studied to evaluate the influence of membrane properties on their performance in desalination by direct contact membrane distillation (DCMD) and vacuum membrane distillation (VMD) processes. The membrane thickness is varied between 23 μm to 125 μm; the pore size is varied from 0.05 μm to 0.45 μm. The porosity is generally high in the range of 0.7 - 0.8. DCMD experiments are performed over a hot brine temperature range of 65 °C to 85 °C and distillate temperature at 25 °C for various brine …

Custom Engineered Nanomaterials For Energetics And Energy Applications, Ani Abraham

Dissertations

Recent interest in reactive material has shifted to more custom formulations targeting specific applications. In this work, preparation and characterization of nanomaterials used for several energetics and energy applications are addressed.

The main challenge of this effort is to design and prepare nanomaterials which have significant improvements associated with combustion dynamics, reaction rates, sensitivity, biocidal effectiveness, moisture stability, and are environmentally safer over the existing energetics. Nanomaterials that are used to defeat stockpiles of chemical and biological weapons, modify ionosphere properties for transmission of optical and radio signals, and for energy storage are prepared under room or cryogenic temperatures via …

Preparation, Ignition And Combustion Of Reactive Metal-Sulfur Nanocomposites, Ziyue Zhong

Theses

Mechanical milling is applied to synthesize reactive metal-sulfur nanocomposites. Specifically, magnesium-sulfur, aluminum-sulfur and zirconium-sulfur nanocomposite powders are prepared. Each powder particle contained homogeneously mixed sulfur and respective metal. These materials are expected to be stable in room air. They are also expected to release sulfur upon ignition; the released sulfur may serve as a biocidal agent. The ignition temperatures of the three prepared sulfur-bearing materials fall in a range of 750 - 1000 K. All prepared materials are successfully ignited in electrostatic discharge experiment as well as in a constant volume explosion experiment. The most sensitive material to spark ignition …

Dissolution Kinetics Of Model Api In Molten Polymer Excipients During Batch Processing, Shen Ji

Theses

In the pharmaceutical industrial application field, hot-melt extrusion (HME) has been recently introduced to develop new solid dosage forms and products. By dissolving the poorly–soluble active pharmaceutical ingredients (API) into water-soluble polymers, the bioavailability of the Class II (with low solubility and high permeability in water) API in Biopharmaceutical Classification System (BCS) could be significantly improved in the body. For readily water-soluble API, HME provides a new approach to produce a controlled release drug system. Hence, pharmaceutical HME is a promising processing method in the pharmaceutical industry.

However, HME has not been widely applied into the pharmaceutical industry. The thermal …

Development And Analysis Of Aluminum-Ptfe Reactive Composite Material, Siva Kumar Valluri

Theses

The shortcomings of micron sized aluminum due to the oxide barrier and two phase loses pose a hindrance for its efficient use as a fuel. In this study a fluoropolymer; Teflon’s inclusion in micron sized -325 mesh aluminum is suggested as a replacement to aluminum. Aluminum Teflon based energetic material see great potential for use in pyrotechnics, propellants and even explosives. A composite with composition Al-PTFE (90-10 wt. %) is prepared through Cryomilling and is shown to be a better method of preparation as compared to room temperature milling. The prepared materials are studied to identify best conditions. The analysis …

Laboratory Studies Of The Biodegradation Of Chemically Dispersed Oil: Effect Of Droplet Size And Nutrient Amendment, Christopher D'Ambrose

Dissertations

Oil spills could have devastating effects on the shorelines, and for this reason, chemical dispersants are commonly used to disperse the oil slick in the water column, preventing it from reaching the shorelines. However, the long term fate of dispersed oil depends on its biodegradation by indigenous microorganisms, which in turn depends on the concentration of nutrients in water and on the droplet size distribution.

Using water from the shorelines of Atlantic City, we placed the water with oil and dispersant inside EPA Baffled Flasks and placed them on rotatory shakers. We selected two speeds: high (250 rpm) and low …

Synthesis Of A Renewable Sourced Thermotropic Polyester With 2,5-Furandicarboxylic Acid, Alicia Marie Marguerite Hurst

Theses

With the rapid depletion of non-renewable sourced materials, unpredictable fluctuations in the prices of fossil fuels, and increased environmental awareness the need to develop biobased materials grows ever more desperate. Furan derivatives sourced from hexoses provide a promising solution for replacing petrochemical based materials. One furan derivative in particular, 2,5-furandicarboxylic acid (FDCA), is especially promising due to its structural similarity to terephthalic acid and potential for use in the production of polyesters similar to PET, PPT, and PBT. This study investigated the synthesis, thermal and liquid crystalline properties of a totally renewable sourced thermotropic polyester based on FDCA. Fructose was …

Computational And Experimental Determination Of The Hydrodynamics In A Stirred Unbaffled Vessel Provided With Angle-Mounted Axial Impellers, Ji Ma

Theses

In most industrial applications, stirred tanks and reactors are typically provided with baffles to improve their mixing characteristics. However, in a number of pharmaceutical production facilities unbaffled vessels are commonly used. The absence of baffles is preferred in such cases because it reduces the potential for contamination and makes cleaning the vessel between batches easier. However, the lack of baffles also has a negative impact on the system’s hydrodynamics since it often results in poor mixing of the batch, especially if the impeller is centrally placed, since the liquid in such a system is subject to a strong tangential flow, …

A Preliminary Investigation Of The Sterile-Filterability Of Bcs Class Ii Drug Nanosuspensions Prepared Via Wet Stirred Media Milling, Parul Ohri

Theses

Drug nanoparticles can achieve targeting capabilities, enhanced dissolution rates and improved bioavailability when injected intravenously. Sterile filtration of drug nanoparticle suspensions (nanosuspensions) is critically needed for administration by intravenous delivery route. Avoiding gamma irradiation and high temperatures, sterile filtration could be an effective process to sterilize drug nanosuspensions. On the other hand, two major challenges must be tackled: drug particles must at least be smaller than the filter pore size and minimum amount of non-toxic stabilizers must be used to prevent side effects like pain on the injection site. The aim of this study is to prepare naproxen (NPX) nanosuspensions …