Matching Items (35)

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Evolution of the temperature distribution of granular material in a horizontal rotating cylinder

Description

Accurate prediction of the particles’ temperature distribution and the time required to heat up the particles is important to maintain good quality products and economical processes for several industrial processes

Accurate prediction of the particles’ temperature distribution and the time required to heat up the particles is important to maintain good quality products and economical processes for several industrial processes that involve thermal treatment. However, we do not have quantitative models to predict the average temperature or particles’ temperature distribution accurately. In this article, we carry out DEM simulations and compute the temporal and spatial evolution of the distribution of the particles’ temperature in rotating cylinders. We present typical examples for different particle properties and operating conditions. The temperature distribution follows what is referred to as a uniform distribution with well defined mean and standard deviation values. Our analysis of these statistical parameters can assist in the prediction of the time required to heat up granular materials and the design of efficient processes.

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  • 2017-06-30

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Asteroid Mobility Using Screw-Powered Vehicles

Description

The role of robotics mobility is essential in the world of research because it allows humans to perform jobs that are dull, dirty, or dangerous without being physically present. A

The role of robotics mobility is essential in the world of research because it allows humans to perform jobs that are dull, dirty, or dangerous without being physically present. A typical robot environment is one that is smooth and predictable. Screw-powered vehicles (SPV's) have commonly been used in these predictable environment situations such as terrestrial applications like mud and snow. However, a gap remains in SPV's traversing complex environments, particularly debris and granular material. The goal is to study the characteristics of how a SPV might move and generate force in such a granular environment for Earth and space. In our study, the chosen granular environment is soda-lime glass beads for easy characterization. This study with glass beads focuses on two separate approaches. The first approach is using a single screw rotating while the apparatus remains static and analyzing the forces that impact the screw. The second approach includes using a full body craft with two double helix screws and analyzing the translational velocity of the craft. This study presents both experimental and computational results using simulations with Multi-Body Dynamics (MBD) and Discrete Element Method (DEM) software packages to investigate the trends of SPV's in a granular environment.

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Date Created
  • 2018-05

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A Quantitative Study on the Effects of Operating Conditions on Heat Transfer in a Rotary Drum

Description

Rotary drums are commonly used for their high heat and mass transfer rates in the manufacture of pharmaceuticals, cement, food, and other particulate products. These processes are difficult to model

Rotary drums are commonly used for their high heat and mass transfer rates in the manufacture of pharmaceuticals, cement, food, and other particulate products. These processes are difficult to model because the particulate behavior is governed by the process conditions such as particle size, particle size distribution, shape, composition, and operating parameters, such as fill level and rotation rate. More research on heat transfer in rotary drums will increase operating efficiency, leading to tremendous energy savings on a global scale. This study investigates the effects of drum fill level and rotation rate on the steady-state average particle bed temperature. 3 mm silica beads and a stainless steel rotary drum were used at fill levels ranging from 10 \u2014 25 % and rotation rates from 2 \u2014 10 rpm. Four heat guns were used to heat the system via conduction and convection, and an infrared camera was used to record temperature data. A three-level, two-factor, full-factorial design of experiments was employed to determine the effects of each factor on the steady-state average bed temperature. Low fill level and high rotation rate resulted in higher steady-state average bed temperatures. A quantitative model showed that rotation rate had a larger impact on the steady-state bed temperature than fill level.

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Date Created
  • 2018-05

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Contact Angle Measurement Reliability Through Washburn Method

Description

This research investigated deionized water contact angle measurement reliability with alumina powder using the Washburn method. This method relates the capillary rise of a liquid through a column of packed

This research investigated deionized water contact angle measurement reliability with alumina powder using the Washburn method. This method relates the capillary rise of a liquid through a column of packed powder to the contact angle of the system. A reference liquid that is assumed to be perfectly wetting, such as hexane due to the low surface energy, must be used to compare to the tested liquid. Consistency was hypothesized to be achieved with more powder structure and consistency of packing between reference and test trials. The three types of packing structures explored in this study were unstructured, visually-structured (user tapped), and machine-structured tapping. It was also hypothesized that similar contact angle results would be found for different packing methods of the same powder and liquid. However, the average contact angle for unstructured packing was found to be 32.9°, while the angle for the tapped structure was only 11.7°. This large deviation between types of packing shows that there are more inconsistencies with the use of this method than just the regulation of the packing structure. There were two similar glass chromatography columns used, but the second column experienced an unknown interference that led to a delay in the hexane uptake into the powder, which then led to invalid contact angle calculations. There was no discernible relationship between the packing structure and the standard deviation between trials, so the more structured packing does not seem to affect the consistency of results. It is recommended to perform more experiments on a single packing type with different apparatuses and a narrower particle size range.

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Date Created
  • 2017-12

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Measurement of Liquid Contact Angle on a Powder

Description

The wettability of powders is an important characteristic for both industry and academia and is often described by the powder’s contact angle with a certain liquid. While there exist many

The wettability of powders is an important characteristic for both industry and academia and is often described by the powder’s contact angle with a certain liquid. While there exist many ways to measure contact angle, it is a portion of the powder technology field that is not fully understood and requires more investigation and research. This study investigates two methods for measuring contact angle, the sessile drop method and the Washburn method, and looks to compare results to determine which method offers the most reliable data in terms of accuracy and repeatability. Two powders - microcrystalline cellulose and aluminum oxide - and three liquids - water, 50 cSt silicone oil, and 350 cSt silicone oil - were used to study the differences between the two measurement techniques as well as the effects of varying fluid viscosity on the measurements. It was found that the sessile drop method proved to be an ineffective method for measuring contact angle when liquid penetration into the powder occurred, as the contact angle changed while the drop penetrated. Initial results showed the contact angle for silicone oil on the powders to be greater than 90°, indicating nonwetting of the surface which was inconsistent with observations. The results from the Washburn method align better with other values in similar studies, but more study is needed to confirm the results gathered in this research.

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Date Created
  • 2016-05

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Conductive Heat Transfer in Rotary Drums

Description

In industrial applications, rotary drums are poorly understood and preform suboptimally when used to process particulates. In order to better understand how these drums work, a statistical experiment was designed

In industrial applications, rotary drums are poorly understood and preform suboptimally when used to process particulates. In order to better understand how these drums work, a statistical experiment was designed to measure the effects of the fill level and rotation rate on the final temperature of the particle bed. A steel rotary drum was set up to be headed by three external heat guns, simulating the conditions under which standard rotary drums are operated. By measuring the bed temperature at steady state, and recording the combination of factors in each run, a regression analysis was run to determine the factor's effects. Fill level was seen to have a small positive effect, rotation rate was seen to have a small negative effect, and the interaction of the two was shown to have a large positive effect. This led the team to conclude that the flow profile of the bed may be the most important factor in heat transfer, and that further research should be done to isolate and study the effect of the flow profile.

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Date Created
  • 2018-05

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Particle Characterization and Imbibition within Industrial Oil Shale

Description

In today's high demand energy industry, oil shale is becoming an increasingly sought-after fossil fuel source, deviating from the more conventional fuel sources. Investigating imbibition, which is the uptake of

In today's high demand energy industry, oil shale is becoming an increasingly sought-after fossil fuel source, deviating from the more conventional fuel sources. Investigating imbibition, which is the uptake of liquids into porous material, provides potential solutions to common industry issues that occur during hydraulic fracturing of shale rock. Particle characterization tests were performed on industrial shale samples cleaned with methanol only, chloroform only, and a mixture of methanol and chloroform. The purposes of these chemicals were for salt extraction, hydrocarbon extraction, and the extraction of both impurities respectively. These characterization tests included bulk and tap density tests, Malvern Mor- phologi G3SE tests for circle equivalent diameter (particle size distribution), high sensitivity circularity, and elongation, Freeman Technology FT4 Powder Rheometer tests for bulk flowability and compressibil- ity, and sessile drop experiments using deionized water, hexane, and silicone oil for hydrophobicity and contact angle measurements. Results show that the methanol cleaned sample had the largest particle size distribution and largest number of symmetrical particles while the chloroform and methanol/chloroform cleaned samples showed similar results with a smaller particle size distribution and more elliptically shaped particles. Based on this, the methanol cleaned sample had the highest compressibility due to the large number of void fractions between the large particles and the smaller particles fitting within these voids. All three samples were highly hydrophobic and showed similar behaviors in the sessile drop tests.

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Date Created
  • 2018-05

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Proxy Assessment of Biospecimen Exposure to Thawed Conditions via Direct Fluorescence Visualization

Description

In the development of personalized medicine and many other clinical studies, biospecimen integrity serves as the prerequisite for not only the accurate derivation of patient- and disease-specific molecular data from

In the development of personalized medicine and many other clinical studies, biospecimen integrity serves as the prerequisite for not only the accurate derivation of patient- and disease-specific molecular data from biological specimens but the meaningful downstream validation of biomarkers. However, a large number of preanalytical variables may influence the quality of biospecimens in an undesired way and ultimately render the samples unsuitable for molecular analysis. The limited ability to directly reduce discrepancies caused by preanalytical variables gives rise to the need for development and retrospective application of appropriate tests for assessment of biospecimen integrity. Nevertheless, the most standard approaches to assessing biospecimen integrity involve nontrivial procedures. Thus, the need for quality control tools or tests that are readily applicable and can produce results in a straightforward way becomes critical. As one of the major ex vivo biomolecular degradation mechanisms, oxidation that occurs when blood plasma and serum samples are exposed to thawed states during storage and processing is hard to forestall and detect. In an attempt to easily detect and monitor the degree of oxidation, the technique of Fluorescence Resonance Energy Transfer (FRET) was examined to determine whether this concept could be employed to monitor exposure of samples to thawed conditions when controlled by spontaneous oxidative disulfide bonding. The intended mode of usage was envisioned as a fluorescence liquid being stored in a separate compartment but within the same test tube as archived plasma and serum samples. This would allow the assessment of sample integrity by direct visualization of fluorescence under a hand-held black light. The fluorescent dynamic range as well as kinetic control of the reaction were studied. While the addition of Cu(II) proved to facilitate excellent dynamic range with regard to fluorescence quenching, the kinetics of the reaction were too rapid for practical use. Further investigation revealed that the fluorescence quenching mechanism might have actually occurred via Intramolecular Charge Transfer (ICT) rather than FRET mediated by oxidative disulfide bond formation. Introduction of Cu(II) via copper metal slowed fluorescence quenching to the point of practical utility; facilitating demonstration that storing at room temperature, refrigerating or freezing the samples delayed fluorescence quenching to different extents. To establish better kinetic control, future works will focus on establishing controlled, thoroughly understood kinetic release of Cu(II) from copper metal.

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Date Created
  • 2018-12

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Statistical Design of Experiment on Homemade Sourdough

Description

This report investigates the effects of autolyzing, fermentation medium, fermentation temperature, and proofing medium on the growth and porosity of 50% whole wheat sourdough bread. A model was designed using

This report investigates the effects of autolyzing, fermentation medium, fermentation temperature, and proofing medium on the growth and porosity of 50% whole wheat sourdough bread. A model was designed using a 24 statistical design of experiment with replicates to screen and quantify the individual and combined effects of the aforementioned factors on the area of a 1 cm cross-sectional cut from each loaf. Fermentation temperature had the single largest effect, with colder fermented loaves being on average 10 cm2 larger than their warmer fermented counter parts. Autolyzing had little individual effect, but the strengthened gluten network abated some of the degassing and overproofing that is a consequent handling the dough or letting it ferment too much. This investigation quantifies how to maximize gluten development and yeast growth to create the airiest whole wheat sourdough, a healthier and easier to digest bread than many commercially available.

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Date Created
  • 2018-05

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A Ground Control System for Studying Locomotion on Granular Media

Description

Current robotic systems are limited in their abilities to efficiently traverse granular environments due to an underdeveloped understanding of the physics governing the interactions between solids and deformable substrates. As

Current robotic systems are limited in their abilities to efficiently traverse granular environments due to an underdeveloped understanding of the physics governing the interactions between solids and deformable substrates. As there are many animal species biologically designed for navigation of specific terrains, it is useful to study their mechanical ground interactions, and the kinematics of their movement. To achieve this, an automated, fluidized bed was designed to simulate various terrains under different conditions for animal testing. This document examines the design process of this test setup, with a focus on the controls. Control programs will be tested with hardware to ensure full functionality of the design. Knowledge gained from these studies can be used to optimize morphologies and gait parameters of robots. Ultimately, a robot can be developed that is capable of adapting itself for efficient locomotion on any terrain. These systems will be invaluable for applications such as planet exploration and rescue operations.

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Date Created
  • 2016-05