149 research outputs found
Determination of Global Extractives in Polyethylene Terephthalate by Heating the Solvent in a Microwave Oven
No full textDETERMINATION OF GLOBAL EXTRACTIVES IN POLYETHYLENE TEREPHTHALATE BY HEATING THE SOLVENT IN A MICROWAVE OVEN By Anuj Vinodchandra Parikh The purpose of this research is to evaluate a method of determining extractives. Instead of a conventional oven, a microwave oven is used to heat the solvent. Attempts are made to duplicate the extraction methodology proposed by the Food and Drug Administration (FDA) in a way that it can be used to determine extractives for microwave-only packages. A test package consisting of crystalline polyethylene terephthalate and paper was selected for the test. A product consisting of a dehydrated mix of pasta and cheese sauce was evaluated to determine the test parameters including the solvent, time, and temperature. Distilled deionized water was selected as a solvent. It was exposed in two different package shapes to counter any microwave heating irregularities. The solvent was heated in packages for 10 minutes in a 700 watt microwave oven at maximum power. The extractives, in each case, were obtained by evaporating the solution under reduced temperature of 60°F (15.5°C) and in vacuum, a method commonly referred to as vacuo. A Rotavapor machine was used for this purpose. The extractives were then dried and weighed. They were further dissolved in chloroform. Chloroform-insoluble extractives were filtered out and further extraction was performed on the solution. The temperature was maintained at 35°F (1.7°C). It was found that the amount of extractives obtained by the conventional FDA method were comparable to the ones obtained by this procedure. In both cases the amount of total extractives for this package fell within the specified limits set by the FDA in milligrams per square inch of contact surface
Parikh Automata over Infinite Words
No full textParikh automata extend finite automata by counters that can be tested for
membership in a semilinear set, but only at the end of a run, thereby
preserving many of the desirable algorithmic properties of finite automata.
Here, we study the extension of the classical framework onto infinite inputs:
We introduce reachability, safety, B\"uchi, and co-B\"uchi Parikh automata on
infinite words and study expressiveness, closure properties, and the complexity
of verification problems.
We show that almost all classes of automata have pairwise incomparable
expressiveness, both in the deterministic and the nondeterministic case; a
result that sharply contrasts with the well-known hierarchy in the
-regular setting. Furthermore, emptiness is shown decidable for Parikh
automata with reachability or B\"uchi acceptance, but undecidable for safety
and co-B\"uchi acceptance. Most importantly, we show decidability of model
checking with specifications given by deterministic Parikh automata with safety
or co-B\"uchi acceptance, but also undecidability for all other types of
automata. Finally, solving games is undecidable for all types
Accelerating Population Balance Model - based particulate process simulations via parallel computing
No full textThe use of Population Balance Models (PBM) for simulating dynamics of particulate systems are inevitably limited at some point by the demands they place on computational resources. PBMs are widely used to describe the time evolutions and distributions of many industrial particulate processes, and its efficient and quick simulation would certainly be beneficial for process design, control and optimization. This thesis is an elucidation of how MATLAB's Parallel Computing Toolbox (PCT), a third-party toolbox called JACKET, and the MATLAB Distributed Computing Server (MDCS) may be combined with algorithmic modification of the PBM to speed up these computations on a CPU (Central Processing Unit), GPU (Graphics Processing Unit) and a computer cluster respectively. Parallel algorithms were developed for three dimensional and four dimensional population balance models incorporating hardware class-specific parallel constructs such as SPMD and gfor. Results indicate significant reduction in computational time without compromising numerical accuracy for all cases except for the GPU. The GPU seemed promising for larger problems despite its limitations of lower clock speeds and on-board memory compared to the CPU. Evaluations of the speedup and scalability further affirm the algorithms' performance.M.S.Includes bibliographical referencesIncludes vitaby Anuj Varghese Prakas
Sex‐Associated Disparities in Industry Payments to US Authors in High‐Impact Rheumatology Journals: Correlation with Author Impact
No full textObjective The aim of this study was to assess sex‐associated disparities in the frequency and magnitude of industry payments to US physician authors in high‐impact rheumatology journals and their correlation with author impact. Methods US authors of publications in four high‐impact rheumatology journals were vetted on Open Payments Database (OPD) for industry payments. The h‐index (an accepted metric of author impact), physician type, and dollar amounts for each OPD category were recorded. Differences in the percentages of male versus female US authors with or without OPD entries, differences in research‐associated and non–research‐associated payments, and differences in h‐indexes were determined. Two hematology, two surgery, and two obstetrics/gynecology high‐impact journals were similarly vetted. Results The h‐indexes of, and industry payments to, US male physician authors were greater than those of and to US female physician authors across all four vetted journal disciplines, with the male‐to‐female ratio of median dollar payments being greatest for rheumatology. Whereas payments to male US physician authors tended to be larger than those to female US physician authors at low h‐indexes, payments to female US physician authors, especially for rheumatology, tended to match and surpass those to male US physician authors as the h‐indexes rose. Conclusion Significant differences exist in industry payments and h‐indexes between male and female US physician authors of publications in high‐impact journals, especially high‐impact rheumatology journals. Sex‐associated differences in industry payments can be attributed, at least in part, to sex‐associated differences in author impact
The unreasonable effectiveness of experiments in constraining nova nucleosynthesis
No full textClassical nova explosions arise from thermonuclear ignition in the envelopes of accreting white dwarfs in close binary star systems. Detailed observations of novae have stimulated numerous studies in theoretical astrophysics and experimental nuclear physics. These phenomena are unusual in nuclear astrophysics because most of the thermonuclear reaction rates thought to be involved are constrained by experimental measurements. This situation allows for rather precise statements to be made about which measurements are still necessary to improve the nuclear physics input to astrophysical models. We briefly discuss desired measurements in these environments with an emphasis on recent experimental progress made to better determine key rates
Quantum transport in graphene nanotransistors
No full textOver the past decade, interest in using graphene in condensed-matter physics and materials science applications has exploded, owing to its unique electrical properties. Narrow strips of graphene, called graphene nanoribbons, also display exotic behavior. A nanoribbon’s edge geometry determines its electronic transport properties, and the rich behavior
of conductance of nanoribbons in response to external potentials makes them ideal for use within transistors.
In this thesis, we work towards creating an accurate model of graphene nanoribbon transistors, and we asses two possible applications which exploit their amazing potential. We begin by outlining the basic theoretical and computational framework for the model developed in this work. We then demonstrate the capability of graphene nanoribbon transistors, with nanopores, to electronically detect, characterize, and manipulate translocating DNA
strands. Specifically, we explore the tunability of such devices, by examining the role of lattice geometry, such as a quantum point contact constriction, on their performance. We perform a demonstration of the ability to detect the passage of double and single-stranded
DNA, through molecular dynamics simulations. The transistors presented are capable of sensing the helical shape of double-stranded DNA molecules, the unraveling of a DNA helix into a planar-zipper form, and the passage of individual nucleotides of a single strand of DNA
through the nanopore. We outline a preliminary analysis on the proper design of a multilayer transistor stack to control both the electronic properties of the conducting membrane, as well as the motion of the DNA. Lastly, we present another type of nanoribbon device,
an all-carbon spintronic transistor for use in cascaded logic circuits. A thorough analysis of the transport properties of zigzag nanoribbon transistors in magnetic fields, in addition to the design and construction of logic gate circuits containing these spintronic transistors, is presented.Submission published under a 24 month embargo labeled 'U of I only', the embargo will last until 2017-05-01The student, Anuj Girdhar, accepted the attached license on 2015-04-18 at 16:01.The student, Anuj Girdhar, submitted this Dissertation for approval on 2015-04-18 at 16:02.This Dissertation was approved for publication on 2015-04-24 at 10:12.DSpace SAF Submission Ingestion Package generated from Vireo submission #7936 on 2015-07-22 at 14:18:16Made available in DSpace on 2015-07-22T22:33:35Z (GMT). No. of bitstreams: 2
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Previous issue date: 2015-04-24Embargo set by: Seth Robbins for item 79875
Lift date: 2017-07-22T22:34:16Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Only Restriction Lifted for Item 79875 on 2017-07-23T09:15:20Z
Enhanced Oil Recovery using Carbonated Polymeric Nanofluids : A New Age Approach to CO2 Utilization and Corrosion Mitigation
No full textThe author would like to thank the CIF facility and its staff, including Mr. Anuj Prajapati, Mr. Zahoor Alam, and Mr. Brijesh. Thanks are also extended to all the members associated with the work.Peer reviewe
The unreasonable effectiveness of experiments in constraining nova nucleosynthesis
No full textClassical nova explosions arise from thermonuclear ignition in the envelopes of accreting white dwarfs in close binary star systems. Detailed observations of novae have stimulated numerous studies in theoretical astrophysics and experimental nuclear physics. These phenomena are unusual in nuclear astrophysics because most of the thermonuclear reaction rates thought to be involved are constrained by experimental measurements. This situation allows for rather precise statements to be made about which measurements are still necessary to improve the nuclear physics input to astrophysical models. We briefly discuss desired measurements in these environments with an emphasis on recent experimental progress made to better determine key rates
The unreasonable effectiveness of experiments in constraining nova nucleosynthesis
No full textClassical nova explosions arise from thermonuclear ignition in the envelopes of accreting white dwarfs in close binary star systems. Detailed observations of novae have stimulated numerous studies in theoretical astrophysics and experimental nuclear physics. These phenomena are unusual in nuclear astrophysics because most of the thermonuclear reaction rates thought to be involved are constrained by experimental measurements. This situation allows for rather precise statements to be made about which measurements are still necessary to improve the nuclear physics input to astrophysical models. We briefly discuss desired measurements in these environments with an emphasis on recent experimental progress made to better determine key rates.Postprint (published version
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