1,722,576 research outputs found
Enhancing the Electron Transfer at Electrochemical Interfaces by Spinel Oxide-Nanostructures
Get PDFL'abstract è presente nell'allegato / the abstract is in the attachmen
A Short Overview on Graphene and Graphene-Related Materials for Electrochemical Gas Sensing
Get PDFThe development of new and high-performing electrode materials for sensing applications is one of the most intriguing and challenging research fields. There are several ways to approach this matter, but the use of nanostructured surfaces is among the most promising and highest performing. Graphene and graphene-related materials have contributed to spreading nanoscience across several fields in which the combination of morphological and electronic properties exploit their outstanding electrochemical properties. In this review, we discuss the use of graphene and graphene-like materials to produce gas sensors, highlighting the most relevant and new advancements in the field, with a particular focus on the interaction between the gases and the materials
Regulation of lifespan by the mitochondrial electron transport chain: reactive oxygen species-dependent and reactive oxygen species-independent mechanisms
No full textSignificance: Aging is a consequence of the accumulation of cellular damage that impairs the capacity of an aging organism to adapt to stress. The Mitochondrial Free Radical Theory of Aging (MFRTA) has been one of the most influential ideas over the past 50 years. The MFRTA is supported by the accumulation of oxidative damage during aging along with comparative studies demonstrating that long-lived species or individuals produce fewer mitochondrial reactive oxygen species and have lower levels of oxidative damage. Recent Advances: Recently, however, species that combine high oxidative damage with a longer lifespan (i.e., naked mole rats) have been described. Moreover, most of the interventions based on antioxidant supplementation do not increase longevity, as would be predicted by the MFRTA. Studies to date provide a clear understanding that mitochondrial function regulates the rate of aging, but the underlying mechanisms remain unclear. Critical Issues: Here, we review the reactive oxygen species (ROS)-dependent and ROS-independent mechanisms by which mitochondria can affect longevity. We discuss the role of different ROS (superoxide, hydrogen peroxide, and hydroxyl radical), both as oxidants as well as signaling molecules. We also describe how mitochondria can regulate longevity by ROS-independent mechanisms. We discuss alterations in mitochondrial DNA, accumulation of cellular waste as a consequence of glyco- and lipoxidative damage, and the regulation of DNA maintenance enzymes as mechanisms that can determine longevity without involving ROS. Future Directions: We also show how the regulation of longevity is a complex process whereby ROS-dependent and ROS-independent mechanisms interact to determine the maximum lifespan of species and individuals
Modeling of non-equilibrium effects on a double wedge configuration in hypersonic flows
Get PDFNumerical simulations are extensively used for the modeling of hypersonic flows characterized by thermal and chemical non-equilibrium phenomena. The accurate modeling of non-equilibrium effects relies on knowledge of reaction rate constants and relaxation parameters, often extrapolated outside their range of applicability.
The objective of this thesis is the validation of the non-equilibrium models conventionally used by the scientific community. To this aim, the flow over a double wedge configuration is simulated for a nitrogen and air gas mixture at hypersonic conditions. The results are compared with experimental work performed at the University of Illinois by Austin and Swantek. The flow governing equations are discretized and solved using a parallel cell centered finite volume solver within COOLFluiD. The accuracy of the simulations is second order in space and first order in time. The convective fluxes are discretized using the AUSM+ scheme and the time is carried out using the fully implicit Backward Euler scheme.
The numerical predictions obtained show significant extent of thermal non-equilibrium between vibrational and translational energy modes, whereas chemical non-equilibrium is present only in the air case, since nitrogen molecules do not significantly dissociate. Two different observables are used for the validation: wall heat-flux, and Schlieren experimental data. In general, the numerical predictions are in good agreement with the experimental results. Only minor differences are observed in the heat flux or the shock structure configuration in the air and nitrogen cases.Submission published under a 24 month embargo labeled 'U of I only', the embargo will last until 2017-05-01The student, Shrutakeerti Mallikarjun Vagishwari, accepted the attached license on 2015-01-30 at 15:32.The student, Shrutakeerti Mallikarjun Vagishwari, submitted this Thesis for approval on 2015-01-30 at 15:57.This Thesis was approved for publication on 2015-02-19 at 09:04.DSpace SAF Submission Ingestion Package generated from Vireo submission #7701 on 2015-07-22 at 14:16:30Made available in DSpace on 2015-07-22T22:32:43Z (GMT). No. of bitstreams: 3
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Previous issue date: 2015-02-19Embargo set by: Seth Robbins for item 79822
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 79822 on 2017-07-23T09:15:32Z
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Real-time Smart Microgrid Simulation: The integration of communication layer in electrical simulation
No full textMicrogrids are smart electrical grid composed of the communication network among its power devices for better operation and control. The information sharing is done locally through measurement but globally by adopting a protocol over the communication network for fast and reliable information exchange for microgrid protection and coordination among the devices present in the power network. In this article, a real-time simulation of a smart microgrid with the emulation of the intelligent electronic devices present in the grid that takes action over the events is proposed using the hardware-in-the-loop methodology. The information exchange between the simulated microgrid and the emulated intelligent trip unit of the circuit breaker is adopted using a physical communication network and User datagram protocol over Ethernet. The unique aspect is to approach the problem of co-simulating the power system simulator with the communication network without platform dependencies to obtain more realistic results. The mathematical models are created using model-based design approach with which a C code can be generated and can be simulated in real-time with any of the digital twins available. The proposed framework is used to test a protection scenario in the microgrid that exchanges the information over Ethernet for measurement and action coordination with the emulated trip unit for stable operation of the microgrid
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