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- All Subjects: Radiation
- All Subjects: Nanoparticles
- Creators: Kozicki, Michael
- Creators: Emady, Heather
- Status: Published
The tool, referred to as Deppy, deposits material via hypersonic impaction, a two chamber process that takes advantage of compressible fluids operating in the choked flow regime to accelerate particles to up several thousand meters per second before they impact and stick to the substrate. This allows for the energetic separation of the synthesis and deposition processes while still behaving as a continuous flow reactor giving Deppy the unique ability to independently control the particle properties and the deposited film properties. While the ultimate goal is to design a tool capable of producing a broad range of nanomaterial films, this work will showcase Deppy's ability to produce silicon nano-particle films as a proof of concept.
By adjusting parameters in the upstream chamber the particle composition was varied from completely amorphous to highly crystalline as confirmed by Raman spectroscopy. By adjusting parameters in the downstream chamber significant variation of the film's density was achieved. Further it was shown that the system is capable of making these adjustments in each chamber without affecting the operation of the other.
The interface of biphasic liquid systems has attracted great attention because it offers a simple, flexible, and highly reproducible template for the assembly of a variety of nanoscale objects. However, certain important fundamental issues at the interface have not been fully explored, especially when the size of the object is comparable with the liquid molecules. In the first MD simulation system, the diffusion and self-assembly of nanoparticles with different size, shape and surface composition were studied in an oil/water system. It has been found that a highly symmetrical nanoparticle with uniform surface (e.g. buckyball) can lead to a better-defined solvation shell which makes the “effective radius” of the nanoparticle larger than its own radius, and thus, lead to slower transport (diffusion) of the nanoparticles across the oil-water interface. Poly(N-isopropylacrylamide) (PNIPAM) is a thermoresponsive polymer with a Lower Critical Solution Temperature (LCST) of 32°C in pure water. It is one of the most widely studied stimulus-responsive polymers which can be fabricated into various forms of smart materials. However, current understanding about the diffusive and phase behaviors of PNIPAM in ionic liquids/water system is very limited. Therefore, two biphasic water-ionic liquids (ILs) systems were created to investigate the interfacial behavior of PNIPAM in such unique liquid-liquid interface. It was found the phase preference of PNIPAM below/above its LCST is dependent on the nature of ionic liquids. This potentially allows us to manipulate the interfacial behavior of macromolecules by tuning the properties of ionic liquids and minimizing the need for expensive polymer functionalization. In addition, to seek a more comprehensive understanding of the effects of ionic liquids on the phase behavior of PNIPAM, PNIPAM was studied in two miscible ionic liquids/water systems. The thermodynamic origin causes the reduction of LCST of PNIPAM in imidazolium based ionic liquids/water system was found. Energy analysis, hydrogen boding calculation and detailed structural quantification were presented in this study to support the conclusions.
Computational Fluid Dynamics (CFD) software, ANSYS Fluent, is utilized to simulate two-phase flows consisting of a carrier gas (Helium) and silicon nanoparticles. The Cunningham Correction Factor is used to account for non-continuous effects at the relatively low pressures utilized in AD.
The nozzle, referred to herein as a boundary layer compensation (BLC) nozzle, comprises an area-ratio which is larger than traditionally designed nozzles to compensate for the thick boundary layer which forms within the viscosity-affected carrier gas flow. As a result, nanoparticles impact the substrate at velocities up to 300 times faster than the baseline nozzle.
This is a test plan document for Team Aegis' capstone project that has the goal of mitigating single event upsets in NAND flash memory caused by space radiation.
Rotary drums are tools used extensively in various prominent industries for their utility in heating and transporting particulate products. These processes are often inefficient and studies on heat transfer in rotary drums will reduce energy consumption as operating parameters are optimized. Research on this subject has been ongoing at ASU; however, the design of the rotary drum used in these studies is restrictive and experiments using radiation heat transfer have not been possible.<br/><br/>This study focuses on recounting the steps taken to upgrade the rotary drum setup and detailing the recommended procedure for experimental tests using radiant heat transfer upon completed construction of the new setup. To develop an improved rotary drum setup, flaws in the original design were analyzed and resolved. This process resulted in a redesigned drum heating system, an altered thinner drum, and a larger drum box. The recommended procedure for radiant heat transfer tests is focused on determining how particle size, drum fill level, and drum rotation rate impact the radiant heat transfer rate.
In collaboration with Moog Broad Reach and Arizona State University, a<br/>team of five undergraduate students designed a hardware design solution for<br/>protecting flash memory data in a spaced-based radioactive environment. Team<br/>Aegis have been working on the research, design, and implementation of a<br/>Verilog- and Python-based error correction code using a Reed-Solomon method<br/>to identify bit changes of error code. For an additional senior design project, a<br/>Python code was implemented that runs statistical analysis to identify whether<br/>the error correction code is more effective than a triple-redundancy check as well<br/>as determining if the presence of errors can be modeled by a regression model.
Rotary drums are used to manufacture pharmaceuticals, cement, food, and other particulate products because of their high heat and mass transfer rates. These processes are governed by particle parameters, such as particle size, particle distribution, and shape, and operating parameters, such as rotation rate and fill level. Enormous energy savings are possible with further research in rotary drums due to potential increases in operating efficiency. This study investigates the drum rotation rate on particle bed temperature at temperatures above 500 °C to see the role that radiation heat transfer plays in this process. 2 mm silica beads and a stainless steel rotary drum were used at a fill level of 25% with rotation rates from 2-10 rpm. A new setup and procedure were developed using heating coils and an IR camera to reach high temperatures. The inner drum wall temperature exceeded the outer drum wall temperature because the steel transmitted more heat into the drum at higher temperatures. Although it was unclear whether the heat transfer rate was affected by the increasing rotation rate, the highest final average particle temperature was obtained at 5 rpm. The particle bed temperature distribution narrowed as the rotation rate increased because, at higher rotation rates, more particles are in contact with the drum wall than at lower rotation rates.
In order to aid future scaling up of the MVA process, the agglomerate size distribution in the MVA system was predicted by utilizing a force balance model coupled with a two-fluid model (TFM) simulation. The particle agglomerate size that was predicted using the computer simulation was validated with experimental data and found to be in good agreement.
Lastly, in order to demonstrate the utility of the MVA system in an air revitalization application, the capture of CO2 was examined. CO2 breakthrough time and adsorption capacities were tested in the MVA system and compared to a vibrating fluidized bed (VFB) system. Experimental results showed that the improved fluidity in the MVA system enhanced CO2 adsorption capacity.