634 research outputs found
Controlling the emergent microstructures in template-directed eutectic solidification for optical applications
Get PDFMesostructured materials with characteristic dimensions of the structure similar to or smaller than the wavelength of light exhibit enhanced optical properties. For successful use in the visible and near-infrared wavelength of light, these structures must be highly ordered and have characteristic features in the hundreds of nanometers to sub-micron size range. Usually, fabricating such structures require sophisticated lithographic techniques or self-assembly approaches, which are well-suited for only a certain class of materials and have limited dimensionality. Emerging work, however, is showing that performing self-assembly within a guiding template can result in the formation of mesostructures not present in either the template or the native self-organizing material. Achieving a diversity of morphologies that can be reconfigured via a simple external tuning knob, while using exactly the same template and material, will advance many fields, including optics, heat transport, and mechanics.
Such an external tuning knob could be the rate of solidification of eutectic alloys. In a eutectic system, multiple solid phases emerge, often in regular structures, as the melt solidifies and these phases could comprise of metals, organics, salts, ceramics, semiconductors, and polymers. The emergence of these microstructures can be controlled by various factors, including the rate of solidification, boundary effects, confinement, and applied thermal gradients. Further control on the emergence of these microstructures could be possible through templating. In this dissertation, particular emphasis is placed on determining the crucial aspects of template design parameters and studying their effects on the microstructure of solidifying eutectic materials.
Chapter 1 surveys the literature on directional solidification of eutectics and template-directed assembly, and establishes the criteria for selecting the starting eutectic and template materials for optical applications. In Chapter 2, molten salt eutectic material, AgCl-CsAgCl2, was explored as photonic crystals. Given the complex nature of thermal profile- and processing-dependent microstructural transition in AgCl-CsAgCl2 eutectic, the template-directed eutectic solidification was carried out using the model AgCl-KCl lamellar eutectic.
For templates with characteristic features much larger than the eutectic, for example, the cage structure template described in Chapter 3, the template design and composition determine the thermal profile during solidification, and thus, control the shape of the solidification front. This resulted in curving of the lamellae of AgCl-KCl eutectic.
A greater control on the emergence of template-directed eutectic microstructures is achieved in templates with characteristic features commensurate to the spacing of the solidifying eutectic. Using lithographically fabricated templates with arrays of pillars in various sizes and geometries, it was determined in Chapter 4 that the boundary effects of templates, substrates, and free surfaces control the orientation of eutectic lamellar microstructures. Understanding the pillar-template-directed orientation of the eutectic phases is an important first step towards designing new mesostructures. In Chapter 5 it was established that the pillar template geometry dictates the diffusion landscape of the solidifying eutectic, which leads to the emergence of symmetries not present in either the native eutectic or the template. This method leads to intricate and rather unexpected patterns, including Archimedean and quasi-crystalline tilings, with potential applications as non-reciprocal metasurfaces, magnetic spin-ice systems, and micro- and nano-lattices with enhanced mechanical properties. Further in Chapter 6 it was shown that for thin layers of eutectic, the pillars act as obstacles that drastically modify the lamellar spacing, which lead to the creation of lamellar faults and thus new morphologies at the pillars. Some of these emergent morphologies bear resemblance to split-ring structures, which are sought for optical metamaterials applications.
Through this dissertation, a thorough understanding of the emergence of template-directed eutectic microstructures has been established. The results summarized in Chapter 7 will form the fundamentals required in designing templates and selecting the eutectic solidification conditions to obtain a particular morphology and/or a diverse set of microstructures, which could further be reconfigured by externally tuning the rate of solidification. Further, these findings suggest that template-directed eutectic solidification is a powerful approach for fabricating mesostructures, which will find use in optical applications and many other modern technologies.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2022-08-01The student, Ashish Ajit Kulkarni, accepted the attached license on 2020-06-11 at 19:08.The student, Ashish Ajit Kulkarni, submitted this Dissertation for approval on 2020-06-11 at 19:12.This Dissertation was approved for publication on 2020-06-12 at 11:17.DSpace SAF Submission Ingestion Package generated from Vireo submission #15426 on 2020-10-02 at 15:30:43Made available in DSpace on 2020-10-07T22:07:10Z (GMT). No. of bitstreams: 17
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Chapter-1 Adv Opt Mat paper.pdf: 76594 bytes, checksum: e8336ad1817e3efee535033a19ae9abf (MD5)
Chapter-2 Adv Opt Mat paper.pdf: 76720 bytes, checksum: 2de75de1e2ba46826a08deaa6c441e9a (MD5)
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Chapter-5 Nature paper.pdf: 77688 bytes, checksum: 167a08d6505c9ab132be85ea5d6eb72c (MD5)
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Previous issue date: 2020-06-12Embargo set by: Seth Robbins for item 116187
Lift date: 2022-10-07T22:07:19Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 116187
Lift date: 2022-10-07T22:44:53Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemAuthor requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Onl
Four ways to improve and strengthen your supply chain
Get PDFDileep Kulkarni, Senior Principal Consultant - Expense Reduction Analysts, Inc.Title from PDF caption (viewed on June 14, 2022).This archived document is maintained by the State Library of Oregon as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Mode of access: Internet from the Oregon Government Publications Collection.Text in English
Selectivity for dimers in pentene oligomerization over acid zeolites
No full textThe reactions of 1-pentene over acid zeolites were investigated in the liquid phase at 473 K. The primary reactions were isomerization, dimerization, and subsequent cracking of dimers. Zeolites consisting of only 10-membered (MFI) or 12-membered rings (FAU, BEA) behaved similarly, with dimerization and subsequent cracking products observed. Zeolites possessing 8-membered ring pores (MOR, FER) showed very different selectivity from each other and from other zeolites. MOR showed almost complete conversion of C10 olefins, such that hexene and butene from cracking were the dominant products. FER showed high activity and selectivity for dimerization, with very small amounts of cracking products observed.Peer reviewe
Bacteriology of chronic suppurative otitis media and its complications
No full textOtitis media, the infection of the middle ear, could be of acute and chronic type (CSOM) which could lead to extra and intra cranial complications. 71 cases of CSOM with the complications were studied. Intraoperative pus was collected in a sterile syringe and was stained with Gram stain and was cultured aerobically and anaerobically. Staphylococcus aureus was the most common pathogen isolated in both complications. Anaerobic culture did not grow any organism. Most of the aerobic organisms were sensitive to cefotaxime
Spariolenus omidvarbrothers Moradmand & Wesal & Kulkarni 2023, sp. n.
No full text<i>Spariolenus omidvarbrothers</i> sp. n. <p>Figs 1A–C, 2A–D, 9A, 11A–C</p> <p> <b>Type material.</b> <b>Holotype:</b> male, <b> IRAN: <i>Sistan & Baluchestan Province:</i></b> Barashk, Bidan Oasis valley, 26.61 N, 60.35 E, 1336 m, 5 June 2017, M. Moradmand & H. Salehi leg. (SMF). <b>Paratypes:</b> 2 females with same data as for holotype (SMF).</p> <p> <b>Etymology.</b> The species is named in honour of the Omidvar brothers, two Iranian adventurers and explorers who travelled around the world in the 1950s and produced a diary and one of the first travel documentaries from extremely remote areas. Their biography inspired the life of many generations including the first author; noun in apposition.</p> <p> <b>Diagnosis.</b> Males of the new species share the bifurcated ET with <i>S. zagros</i> Moradmand & Jäger, 2011; <i>S. fathpouri</i> Moradmand, 2017; <i>S. mansourii</i>, and <i>S. bakasura</i> <b>sp. n.</b>). They can be distinguished from the latter three species by subequal RET and PET (vs. RET obviously longer than PET). They differ from <i>S. zagros</i> by PET 1/3 of RET in width (vs. similar width of PET and RET in <i>S. zagros</i>) (Fig. 1C). The female epigyne shows a unique MS (widened medially and extended longitudinally, Fig. 2A) (vs. MS narrow and barely visible in the rest of congeners).</p> <p> <b>Male</b> (holotype): <i>Measurements.</i> TL 14.1, PL 6.6, PW 5.7, AW 2.5, OL 7.5, OW 4.5. <i>Eyes</i> (Fig 11A). AME 0.33, ALE 0.75, PME 0.48, PLE 0.83, eye interdistances: AME-AME 0.18, AME-ALE 0.03, PME-PME 0.17, PME-PLE 0.62, AME-PME 0.21, ALE-PLE 0.57, clypeus-AME 0.71, clypeus-ALE 0.21. <i>Spination.</i> Palp 131, 101, 2121; Legs: Femur I–III 323(2), IV 321; Patella I–IV 101; Tibia I 131 10, II 232 10, III 1318, IV 2226; Metatarsus I–III 1014, IV 3036. <i>Measurements of palp and legs.</i> Palp 9.8 [3.2, 1.3, 2.2, 3.1], I 40.6 [10.8, 3.8, 11.5, 11.7, 2.8], II 46.0 [12.2, 4.1, 13.7, 13.2, 2.8], III 35.2 [10.1, 3.7, 10.2, 9.1, 2.1], IV 36.0 [10.2, 3.1, 10.2, 10.1, 2.4]. Leg formula: II I IV III. Chelicerae with 3 promarginal and 5 retromarginal teeth, and 10 intermarginal denticles.</p> <p> <i>Palp.</i> As in diagnosis, with cymbium slightly longer than tibia, BRB present, vRTA shorter than dRTA, dRTA pointed and vRTA rounded in retrolateral view, PET slightly shorter than RET, and both are long and slim, and not covering each other in ventral view. Conductor hyaline and extending beyond or roughly the same length as ET (Figs 1A–C).</p> <p> <i>Colouration.</i> Light brown to beige in body with dim to dark grey bands on carapace and legs. Dorsal opisthosoma with chevron shaped markings (Fig. 11A).</p> <p> <b>Female</b> (paratype): <i>Measurements.</i> TL 13.5, PL 7.2, PW 6.3, AW 3.6, OL 6.3, OW 4.5. <i>Eyes.</i> AME 0.31, ALE 0.80, PME 0.50, PLE 0.97, eye inter distances:AME-AME 0.18, AME-ALE 0.07, PME-PME 0.27, PME-PLE 0.63, AME-PME 0.32, ALE-PLE 0.71, clypeus-AME 0.87, clypeus-ALE 0.28. <i>Measurements of palp and legs.</i> Palp 10.4 [3.1, 1.7, 2.3, 3.3], I 32.8 [9.1, 3.8, 9.6, 8.1, 2.2], II [missing], III 29.6 [8.7, 3.5, 8.2, 7.1, 2.1], IV 31.1 [9.1, 3.6, 8.5, 7.8, 2.1]. <i>Spination.</i> Palp 131, 101, 2221, 1014; Legs (leg II missing): Femur I, III 323, IV 321; Patella I, III–IV 001; Tibia I 111(10), III 1118, IV 2126; Metatarsus I, III 1014, IV 3036. Chelicerae with 3 promarginal and 5 retromarginal teeth, cheliceral furrow with around 20 intermarginal denticles.</p> <p> <i>Female copulatory organ.</i> As in diagnosis, with EF wider than long, AB absent, CO small, MEP diagonaly extended (Fig. 2A); TC extending laterad beyond FC and SC (Figs 2B–C).</p> <p> <i>Colouration.</i> Same as for male but with lighter colour bands on legs (Fig. 11B).</p> <p> <b>Distribution and habitat preferences.</b> Known only from the type locality (Fig. 13). Specimens were collected at night on boulders and rocks. The type locality was an oasis in a small canyon dominated by palm trees (Fig. 11C). An unknown species of the genus <i>Eusparassus</i> Simon, 1903 was sympatrically sampled on plants and vegetation.</p>Published as part of <i>Moradmand, Majid, Wesal, Mohammad Wasil & Kulkarni, Siddharth, 2023, Taxonomic revision of the troglophile Spariolenus spiders (Araneae: Sparassidae) in South and West Asia, pp. 77-95 in Zootaxa 5380 (1)</i> on pages 78-81, DOI: 10.11646/zootaxa.5380.1.6, <a href="http://zenodo.org/record/10212761">http://zenodo.org/record/10212761</a>
Task allocation for networked autonomous underwater vehicles
No full textUnderwater Acoustic Sensor Networks (UW-ASNs) consist of stationary or mobile nodes such as Autonomous Underwater Vehicles (AUVs), which may be classified as propeller-driven vehicles and gliders, that are equipped with a variety of sensors for performing collaborative monitoring tasks. UW-ASNs are envisioned for missions like oceanographic data collection, ocean sampling, offshore exploration, disaster prevention, tsunami and seaquake warning, assisted navigation, distributed tactical surveillance, and mine reconnaissance. A task allocation and optimization framework for networked AUVs that participate as a team to accomplish such missions is developed in this work. These missions entrusted to the AUVs are sometimes critical to human life and property, are bound by severe time and energy constraints, and involve a high degree of inter-vehicular communication. The objective of the framework is to form the best possible team, which is a subset of all deployed AUVs that is best suited to accomplish the mission, while adhering to the constraints. Successful completion of the mission is dependent on effective communication between the networked AUVs and to achieve this a geocasting based networking framework is also proposed. Research specific to this area has been limited. Hence, a framework based on energy minimization for the team of AUVs to complete the mission in given time bound is proposed. Further, the effect of size of geocast region, effect of underwater current on the choice of geocast region and on localized nature of the problem, and the performance of Propeller Driven Vehicles (PDVs) and gliders is compared.M.S.Includes abstractIncludes bibliographical referencesby Indraneel S. Kulkarn
Linear Loop Transformations in Optimizing Compilers for Parallel Machines
No full textWe present the linear loop transformation framework which is the formal basis for state of the art optimization techniques in restructuring compilers for parallel machines. The framework unifies most existing transformations and provides a systematic set of code generation techniques for arbitrary compound loop transformations. The algebraic representation of the loop structure and its transformation give way to quantitative techniques for optimizing performance on parallel machines. We discuss in detail the techniques for generating the transformed loop and deriving the desired linear transformation. Key Words: Dependence Analysis, Iteration Spaces, Parallelism, Locality, Load Balance, Conventional Loop Transformations, Linear Loop Transformations Corresponding author. y Parallel Systems Group, Department of Computer Science, 10 King's College Road, University of Toronto, Toronto, ON M5S 1A4, CANADA. Email: [email protected] Kulkarni and Stumm: Linear Loop Transformations 2 1..
High speed dynamic simulation of power systems
No full textOne of the Dynamic Security Assessment (DSA) tools that electric utilities use is transient stability software. In the changing utility industry, these tools will be relied on even more in the future, as transmission systems become more stressed. A problem with time domain transient stability simulations is that they often require large amounts of computer resources. Much research has and is being done in an attempt to reduce the computational time required by these simulations. This thesis considers two approaches to this problem. The first approach is to use a predictor-corrector integration scheme to simulate the power system. In this approach, the classical model of a generator, with linear load models, is considered.In the second approach, methods from the Krylov subspace family of methods are considered, within the framework of the Simultaneous Implicit (SI) approach. Thus, the latter are used, with the trapezoidal integration scheme and the Newton-Raphson method, to simulate detailed power system models. The two-axis model for generators, with an IEEE type I excitation system and nonlinear load models, is used. The Krylov subspace family of methods generally performs well on vector and parallel computers, as well as on sequential machines. Only limited success was achieved with the traditional application of these methods. However, good results were obtained by designing and using the dishonest preconditioner (DP), a preconditioning strategy designed for the transient stability problem. The DP has parameters that can be used to tune it for the specific power system being simulated. Although it was not considered in this work, the framework of the DP could allow the simultaneous use of more than one linear solver technique.Made available in DSpace on 2011-05-07T13:04:40Z (GMT). No. of bitstreams: 2
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Use of neuraxial blockade in cases of anticipated difficult airway in pediatric patients – A safer option
No full textThe use of Spinal Anaethesia in Pediatric patient is still practiced with apprehension at most of the centers. With increasing reservations of practicing general anaestheia with respect to later cognitive functions, spinal anaesthesia is definitely a better alternative. We share the management of two anticipated difficult airway cases using the neuraxial block
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