258 research outputs found
Scientometric Portrait of Nobel Laureate Venkatraman Ramakrishnan
Get PDFThe study presents an analysis of 165 research papers by Nobel Laureate Venkatraman Ramakrishnan published during 1977 to 2019 in the diverse field of science such as Biochemistry, Genetics and Molecular Biology, Medicine, Chemistry, Neuroscience, Immunology and Microbiology, Physics and Astronomy, Engineering and Materials Science. The highest number of publications contributed during the 2nd and 4th decade with 49 (29.70%) papers each. His paper entitles “Structure of the 30s ribosomal subunit” got maximum 1560 citations. Kelley, A. C. Was the most collaborative author and Europe was the most dominant continent collaborating with 132 papers whereas the United States was the top collaborated country with 100 (60.61%) papers. In the context of authorship pattern Triple authored papers were dominated with 34 (20.61%) papers. Among the most funding Sponsored body Agouron Institute topped the list with 23 (13.94%) papers, on the other hand, The Medical Research Council Laboratory of Molecular Biology, United Kingdom was the most contributed affiliation with 91 (55.15%) papers. In term of most preferred source and the most preferred subject of publications were Science with 23 (13.94%) and Biochemistry, Genetics and Molecular Biology with 97 (58.79%) papers respectively
Proceedings of the 28th Conference of Cement Microscopy
No full textBruce W. Berdenier (with Dawadi, S., Ramakrishnan, V,) is a contributing author, “Surface Morphology of Reactive Powder Concrete Containing Arsenic , pp. 205-226.
The annual meeting of the International Cement Microscopy Association consistently contributes new and innovative research on a variety of cement and concrete topics. The 2006 event featured 18 papers by international experts from universities, research institutes, and other organizations on topics including petrographic analysis, x-ray diffraction, sulfate investigation, fly ash analysis, and more. Published by ICMA
Nonlinear stochastic dynamics of a nanomechanical resonator coupled to a single electron transistor
No full textNanoelectromechanical systems (NEMS) comprise nanometer to micrometer scale mechanical oscillators coupled to electronic devices of comparable dimensions. NEMS have great potential for sensor applications as well as for exploring fundamental physics. The dynamics of a nanomechanical resonator coupled to a single electron transistor (SET) is considered in the Duffing regime using a master equation approach and a Langevin approach. In the first approach, the master equations are derived and solved using a finite element method as well as a moment approximation method for both the single-well and the (inverted) double-well Duffing potentials. It is observed that the SET damps the resonator motion much more effectively in the single-well Duffing case in comparison with the linear case. In the double-well case we observe the existence of a limit cycle wherein the SET and the resonator exist in a state of dynamic equilibrium. This is followed by the onset of instability in the numerical solutions. The results from the master equation approach are used in a numerical fitting procedure to characterize the damping term in the averaged equations of motion of the system. It is observed that a linear damping term provides the best fit in all cases except for the strongly nonlinear regime. Based on this result, a Langevin equation is written down from which a Fokker-Planck equation is derived for the system. The Fokker-Planck equation is solved analytically, in closed form, for the steady state. In the time dependent case, the equation is solved using a finite element method and the results are shown to be in qualitative agreement with those obtained using the master equation approach. Therefore it is established that the SET-resonator system attains a steady state much more rapidly in the single-well Duffing regime. Finally, the steady state analytical solution to the Fokker-Planck equation is utilized to show that the steady state effective temperature is lower in the presence of the single-well Duffing nonlinearity.Ph.D.Includes bibliographical references (p. 144-147)
Exploring image recognition: applying convoluted neural networks and learning to recognize safe cyclists
Get PDF"Today, there is a need to focus on the mobility revolution that is currently taking place. With the advent of more intelligent data gathering, there is also a growing need for using existing technology and infrastructure to achieve this goal, without incorporating expensive, complicated systems. As single-occupancy give way to shared mobility solutions, combined with regular mass transit and pedestrian-aware street infrastructure (traffic lights, crosswalks etc.), there is a large ""networked mobility system'' that has the potential to be tapped. Moreover, autonomous cars will be here soon, to add to the mix.
With statistics showing an increase in bicyclist related crashes over the last decade and an increase in bicycle-borne road users, there is a necessity for cities and autonomous vehicles to build bicycle safety into their adaptation to the ""driverless future"". This paper is an exploration into the use of a Convolutional Neural Network (CNN) based Machine Learning (ML) algorithm to identify bicycle-borne road users, who wear helmets.
We use a pre-made CNN framework-YOLO (You Only Look Once), and built around it further. After a brief proof-of-concept test on a publicly available dataset (including extraction, parsing and detection), the algorithm was modified. Some important features were added, such as identifying license plates, faces and encrypting them. Further, there is also a detailed account of using the ML capabilities that the framework is built with, and training it to identify bicycle-borne road users wearing a helmet."Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2019-08-01The student, Ramakrishnan Narayanan, accepted the attached license on 2017-07-21 at 13:17.The student, Ramakrishnan Narayanan, submitted this Thesis for approval on 2017-07-21 at 13:34.This Thesis was approved for publication on 2017-07-21 at 13:47.DSpace SAF Submission Ingestion Package generated from Vireo submission #11580 on 2018-03-02 at 13:03:11Made available in DSpace on 2018-03-02T20:02:40Z (GMT). No. of bitstreams: 2
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Erratum: Correction to: Work-Related Stressors Among Maternal, Infant, and Early Childhood Home Visiting (MIECHV) Home Visitors: A Qualitative Study (Maternal and child health journal (2018) 22 Suppl 1 (62-69))
Get PDFThe article "Work-Related Stressors Among Maternal, Infant, and Early Childhood Home Visiting (MIECHV) Home Visitors: A Qualitative Study", written by Paige J. Alitz, Shana Geary, Pamela C. Birriel, Takudzwa Sayi, Rema Ramakrishnan, Omotola Balogun, Alison Salloum and Jennifer T. Marshall, was originally published electronically on the publisher's internet portal (currently SpringerLink) on 31 May 2018 without open access. With the author(s)' decision to opt for Open Choice the copyright of the article changed on 25 July 2018 t
Influence of tandem axle on pavement responses and weight limit equivalency
Get PDFThe student, Aravind Ramakrishnan, submitted this Thesis for approval on 2020-12-08 at 12:33.This Thesis was approved for publication on 2020-12-08 at 17:03.DSpace SAF Submission Ingestion Package generated from Vireo submission #16088 on 2021-03-04 at 16:20:44Currently, pavements are designed using layered elastic theory (LET), which makes it easy to obtain the responses for a given loading configuration. However, LET minimizes the influence of axle loading configurations on pavements. Axle load limits for single (20 kips) and tandem axle (34 kips) are intended to be set so that the damage they produce is the same. In other words, axles at their corresponding weight limits are considered equivalent. Because pavement layers are more complicated than a linear elastic material, LET tends to underpredict loading responses and, hence, the damage. Therefore, to understand the effect of loading configuration on asphalt concrete (AC) behavior, Actual tandem loading and flexible pavement structure were modeled using finite element. The influence a 4.5-ft spaced tandem axle on flexible pavement responses and strain recovery were qualitatively assessed. The results showed that the effect of a tandem axle was highly pronounced for vertical strain on the subgrade, followed by that on the granular base, and then finally the transverse strain at bottom of the AC. Such responses could be approximately 1.5 to 1.75 times that of the single axle model. Stress-pulse analysis suggested that a tandem axle could be simulated accurately in laboratory tests. Although stress-pulse magnitude and shape (when no overlap is observed) are known to be independent of speed, loading-pulse duration can be calculated to identify the rest period. Similarly, domain analysis suggested that damage potential was affected by temperature and speed, which should be considered in platoon designs. Transfer functions from Mechanistic Empirical Pavement Design Guide (MEPDG) were used to compute pavement damage. Tandem axle (34 kips) and single axle (20 kips) were found to be inequivalent, confirming that the damage of the tandem axle was higher than single axle. For the given specific case, tandem axle weight of 30 kips was found to be equivalent to single axle (20 kips). This equivalency might be material, speed, tandem spacing, and structure dependent. Given the national goods movement, national weight limits should be applied after establishing an equivalency factor that consider pavement damage mechanistically.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2022-12-01The student, Aravind Ramakrishnan, accepted the attached license on 2020-12-08 at 12:17.Made available in DSpace on 2021-03-05T21:42:51Z (GMT). No. of bitstreams: 2
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Privacy Violation and Detection Using Pattern Mining Techniques
Get PDFPrivacy, its violations and techniques to bypass privacy violation have grabbed the centre-stage of both academia and industry in recent months. Corporations worldwide have become conscious of the implications of privacy violation and its impact on them and to other stakeholders. Moreover, nations across the world are coming out with privacy protecting legislations to prevent data privacy violations. Such legislations however expose organizations to the issues of intentional or unintentional violation of privacy data. A violation by either malicious external hackers or by internal employees can expose the organizations to costly litigations. In this paper, we propose PRIVDAM; a data mining based intelligent architecture of a Privacy Violation Detection and Monitoring system whose purpose is to detect possible privacy violations and to prevent them in the future. Experimental evaluations show that our approach is scalable and robust and that it can detect privacy violations or chances of violations quite accurately. Please contact the author for full text at [email protected]
Role of public libraries in the national movement in Kerala
Get PDFHigh degree of participation by all classes of people at various levels was the distinctive feature of national movement in Kerala. This was made possible by the wide public library network that existed in the region. In Kerala the national movement evolved from a series of movements. Most of them were geared up by groups of people connected to library movement. The village libraries acted as discussion forums for the common man by extending the reach of the regional press, regularly conducting classes on political and social aspects, and organizing cultural and literary programmes. By following a participatory governing system the libraries trained the people in democratic form of government also. With the libraries enabling the emergence and marshaling of peoples’ opinion, all classes of people in Kerala exhibited a high degree of political and social consciousness. The rural libraries thus helped the national movement go far beyond its original elite intellectual confines. The entry of the masses into active political life, which they facilitated, helped the quick elimination of princely states in Kerala, and establishment of parliamentary democracy based on universal franchise. The class character of the national movement in Kerala was more or less based on the proletarian characters and that aspect was responsible for bringing leftists into political power for which contribution of the village libraries was unique. [Extended abstract and full paper available in archive
“MODERNIZATION OF TRADITION”: CONTESTED DISCOURSES AND NEGOTIATED IDEOLOGIES OF FAIRNESS, GENDER, AND MORALITY IN THE SOUTH INDIAN MEDIA
No full textRights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author
Enhanced terahertz emission from thin film semiconductor/metal interfaces
No full textTerahertz light is electromagnetic radiation, similar to visible light. The photons that the terahertz light is comprised of carry a much smaller amount of energy compared to the visible light photons. Unlike visible light, terahertz light can pass through materials like plastic, cardboards, wood etc.; a very useful property which enables it to replace harmful X-rays in many security applications. However, it is not possible to see the terahertz photons with our naked eyes, and it requires special detectors to observe them. A lot of attention has been drawn to terahertz radiation recently because of its potential use in various applications in national security (as mentioned before), and in the biomedical and the semiconductor industries. Essential to any terahertz device is a suitable terahertz source. There are different methods to generate this type of radiation. After the advent of ultrafast lasers, an optical technique was developed which became very popular afterwards. In very simple terms, this technique can be considered as producing an extremely quick disturbance in a suitable material using an extremely quick flash of laser light. Here the phrase `extremely quick' refers to femtosecond time scales where one femtosecond is one millionth of one billionth of a second. The quick electromagnetic disturbance can lead to the emission of a pulse of electromagnetic radiation of a different frequency: terahertz light. Certainly, this process depends on the material in which the disturbance is created, which we will see in a bit more detail below. It is this method of terahertz generation we focus on in this thesis. Let us now have a closer look at this. Only certain materials have this property of converting a flash of laser light efficiently into a flash of terahertz light, for example, some semiconductors. What type of a disturbance can a flash of laser light, (a laser pulse), create in such a material? In the case of semiconductors, the incident light pulse can lead to the excitation of mobile conduction electrons by providing them with the required energy. The semiconductor becomes momentarily a conductor. If it was initially kept under an external voltage bias, a momentary current is thus induced by the light pulse. A time-varying current can act as a source of electromagnetic waves. The emitted flash of light in this case is a terahertz pulse. Similar momentary disturbances can also be produced in certain nonlinear crystals without really exciting electrons from their bound states, but by causing an ultrafast displacement of the bound charges. In both these cases, the emitted light pulse carries information about the material's response to the femtosecond flash of light, which in fact is information about the material per se. For example, we see that the illumination of graphite with femtosecond laser pulses results in the emission of terahertz light pulses. The properties of the emitted terahertz pulse are suggestive of a transient photocurrent produced in the material. Graphite consists of stacks of atomic planes of carbon which are loosely attached to each other. Electric conductivity along a direction perpendicular to these planes is known to be very low as in this case electrons have to jump from one plane to the other. However, in our experiments the emitted terahertz pulses indicate a resultant photocurrent flowing in that direction. Oxidized copper surfaces are known to act as a semiconductor-diode. A semiconductor diode is a device which restricts the electric current to flow through it in only one direction. In the case of oxidized copper surfaces, this is possible by a potential barrier formed at the interface between copper and cuprous oxide. When a femtosecond light pulse excites electrons at such an interface, and frees electrons in it, a quick pulse of current flows across the interface. This transient current emits a terahertz pulse. The same idea can also be applied to different other semiconductor-metal interfaces. We have shown that terahertz pulses can be produced by exciting thin films of germanium and silicon deposited on a gold substrate. If the thin films of these semiconductors prepared on a glass substrate are illuminated with femtosecond light pulses, the emitted terahertz pulses are very feeble. When the thin films of the semiconductors are on a gold substrate, a surprising enhancement of the generated terahertz light from such thin films is observed. The later part of the thesis concentrates on the different possible ways in which the gold substrate can contribute to the enhancement of terahertz radiation from thin films. When coherent laser light is incident on an extremely thin film of a semiconductor material deposited on a metal surface, light reflected from the top and the bottom of the film can result in a complete or partial reduction of the reflected light. It is equivalent to trapping the light inside the film, which leads to enhanced absorption in the thin film. This is sometimes called `coherent optical absorption'. Very strong absorption of the pump light can be achieved in thin films as compared to bulk materials, as a result of this. When light is strongly absorbed by the semiconductor, more electrons will be freed and a stronger transient current can be produced which can result in a stronger terahertz emission. This leads to the counter-intuitive result that less material emits more terahertz light. The concentration of laser light inside the terahertz generation material can also be done by making use of surface plasmon excitation. Surface plasmons are light waves bound to the interface between a metal and a dielectric. In our case, since the terahertz generation takes place at the interface between a metal and a semiconductor, surface plasmons can play a role in the process. As surface plasmons are bound to the interface, they can enhance the local intensity of the pump light at the interface where the generation of terahertz radiation takes place. Using this method, we demonstrate the enhancement of terahertz emission from a layer as thin as a single molecular layer of a nonlinear optical material called hemicyanine. We also go on to show that enhanced terahertz emission can be achieved from semiconductors deposited on a nanostructured metal surface, where again surface plasmons are excited. Concentration of the laser light intensity using plasmonics also leads to terahertz emission from the metal surfaces itself, i.e., without any semiconductor on top. In short, this thesis discusses the possibilities of terahertz generation from ultrathin semiconductor layers, metals and their interfaces, and on different optical techniques to enhance the terahertz emission. These techniques not only help in the study of the properties of ultrathin layers of materials, but can also help in miniaturizing terahertz sources for various applications.Imaging Science & TechnologyApplied Science
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