1,589 research outputs found

    On-road emissions evaluation of student-produced biodiesel

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    UT Biodiesel is a small scale, student run Used Frying Oil (UFO) to biodiesel production program at the University of Tennessee, Knoxville. A single batch transesterification reaction using methanol and potassium hydroxide (KOH) as the catalyst is used to produce biodiesel from UFO collected from UT Dining Services. A warm deionized water wash is used to remove contaminants from the biodiesel. A heat and settle method is used to dry the biodiesel. The processor has been shown to be capable of producing fuel that meets the ASTM D6751 specification for biodiesel. The project uses in-house testing to ensure the quality of the fuel. In-house tests include methanol content, water content, total glycerin, and acid number. This study evaluates the on-road emissions of the student-produced biodiesel in a modern diesel vehicle. The test vehicle is powered by a GM 1.9 liter direct injected turbo diesel using cooled EGR. The vehicle is equipped with a diesel oxidation catalyst and a diesel particulate filter. An Autologic five gas analyzer was used to evaluate tailpipe emissions on a prescribed driving cycle. An Autologic heavy duty smoke meter was used to evaluate smoke opacity using a stationary test. Biodiesel blends of B20 and B50 were evaluated against ultra low sulfur diesel fuel (ULSD) and neat biodiesel, B100

    Fuel Economy and Greenhouse Gas Reduction Potentials of Advanced Combustion Modes in Light-Duty Vehicles: A Well-to-Wheel Analysis using Vehicle Systems Simulations with Experimental Engine Data

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    Vehicle fuel efficiency and emissions regulations are driving a radical shift in the need for high efficiency powertrains along with control of criteria air pollutants and greenhouse gases. High efficiency powertrains including vehicle electrification, engine downsizing, and advanced combustion concepts all seek to accomplish these goals. Homogeneous charge compression ignition (HCCI) concepts have been proposed have not been able to demonstrate the controllability to operate over a sufficient engine speed and load range to make it practical for implementation in production vehicles. In-cylinder blending of gasoline and diesel to achieve reactivity controlled compression ignition (RCCI) has been shown to reduce NOX and PM emissions while maintaining or improving brake thermal efficiency as compared to conventional diesel combustion (CDC). The RCCI concept has an advantage over many advanced combustion strategies in that the fuel reactivity can be tailored to the engine speed and load allowing stable low-temperature combustion to be extended over more of the light-duty drive cycle load range. The potential for advanced combustion concepts such as RCCI to reduce drive cycle fuel economy and emissions is not clearly understood and is explored in this research by simulating the fuel economy and emissions for a multi-mode RCCI-enabled vehicle operating over a variety of U.S. drive cycles using experimental engine maps for multi-mode RCCI, CDC and a 2009 port-fuel injected (PFI) gasoline engine. Simulations are completed assuming a conventional mid-size passenger vehicle with an automatic transmission. RCCI fuel economy simulation results are compared to the same vehicle powered by a representative 2009 PFI gasoline engine over multiple drive cycles Engine-out drive cycle emissions are compared to CDC and observations regarding relative gasoline and diesel tank sizes needed for the various drive cycles are also summarized. The well-to-wheel energy and greenhouse gas emissions from these drive cycle simulations running carious amounts of biofuels are examined and compared to the state-of-the art in conventional, electric and hybrid powertrains

    Google+ vs Facebook: The Comparison

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    Social networks are a varyingly popular tool used to connect with friends, colleagues and/or family. Recently, Facebook has been at the top of the social network food chain, with Bebo and MySpace decreasing in users and the huge increase of users joining Facebook in such a short time. Google have just recently launched Google+, a social networking site. This is not the first time that Google have attempted to break into the social networking scene but it is possible that these failed attempts may have taught them something. As Facebook’s user base is extremely diverse, spreading across different countries, races, ages, professions, and interests, to name a few, this network is a good model to compare new rival Google+ to. Google+ has set out to do the same things as Facebook but better to try and steal away some of that high power and necessity that Facebook has gained. Facebook has News feed, Google has Stream. Facebook has Lists, Google has circles. Facebook has like’s, Google has +1. Facebook accounts for 10% of overall internet usage. This paper will look at various comparables between the two social networks and analyse the better functionality, design and ease of use. It will then conclude a verdict on which is the better social network to use overall.

    Maximizing sparsity of wavelet representations via parameterized lifting

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    Our goal is to determine the wavelet basis that represents a given signal as sparsely as possible. In a previous paper [1], we proposed a novel, two-parameter method for designing a stable biorthogonal wavelet basis which maximizes the sparseness of a signal’s wavelet representation. We chose the Gini index as a measure of sparsity and sparsify a signal by lifting the wavelet basis with the parameters that maximize the Gini index of the resulting wavelet representation. In this paper we show an efficient manner of calculating the optimal parameters obtained by taking the derivative of the wavelet coefficients through the differentiation of the Gini Index. This allows us to find the parameters that yield the most sparse (in a Gini Index sense) set of wavelet coefficients in a fast, effective manner. Index Terms — Wavelet transforms, Signal representations, Signal processing, Adaptive signal processing, Data compressio

    Nurses\u27 Alumnae Association Bulletin, May 1963

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    President\u27s Letter Alumnae Meetings, 1962 Building Fund Mediocrity Hospital Report Alumnae Notes Social Committee Student Activities Marriages, New Arrivals and Necrology Annual Giving Fund Driv

    Well-to-wheel analysis of direct and indirect use of natural gas in passenger vehicles

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    AbstractThe abundance of natural gas in the United States because of the number of existing natural gas reserves and the recent advances in extracting unconventional reserves has been one of the main drivers for low natural gas prices. A question arises of what is the optimal use of natural gas as a transportation fuel. Is it more efficient to use natural gas in a stationary power application to generate electricity to charge electric vehicles, compress natural gas for onboard combustion in vehicles, or re-form natural gas into a denser transportation fuel? This study investigates the well-to-wheels energy use and greenhouse gas emissions from various natural gas to transportation fuel pathways and compares the results to conventional gasoline vehicles and electric vehicles using the US electrical generation mix. Specifically, natural gas vehicles running on compressed natural gas are compared against electric vehicles charged with electricity produced solely from natural gas combustion in stationary power plants. The results of the study show that the dependency on the combustion efficiency of natural gas in stationary power can outweigh the inherent efficiency of electric vehicles, thus highlighting the importance of examining energy use on a well-to-wheels basis

    Myosin II Controls Junction Fluctuations to Guide Epithelial Tissue Ordering.

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    Under conditions of homeostasis, dynamic changes in the length of individual adherens junctions (AJs) provide epithelia with the fluidity required to maintain tissue integrity in the face of intrinsic and extrinsic forces. While the contribution of AJ remodeling to developmental morphogenesis has been intensively studied, less is known about AJ dynamics in other circumstances. Here, we study AJ dynamics in an epithelium that undergoes a gradual increase in packing order, without concomitant large-scale changes in tissue size or shape. We find that neighbor exchange events are driven by stochastic fluctuations in junction length, regulated in part by junctional actomyosin. In this context, the developmental increase of isotropic junctional actomyosin reduces the rate of neighbor exchange, contributing to tissue order. We propose a model in which the local variance in tension between junctions determines whether actomyosin-based forces will inhibit or drive the topological transitions that either refine or deform a tissue

    The N250 Brain Potential to Personally Familiar and Newly Learned Faces and Objects

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    Studies employing event-related potentials have shown that when participants are monitoring for a novel target face, the presentation of their own face elicits an enhanced negative brain potential in posterior channels approximately 250 ms after stimulus onset. Here, we investigate whether the own face N250 effect generalizes to other highly familiar objects, specifically, images of the participant’s own dog and own car. In our experiments, participants were asked to monitor for a pre-experimentally unfamiliar target face (Joe), a target dog (Experiment 1: Joe’s Dog) or a target car (Experiment 2: Joe’s Car). The target face and object stimuli were presented with non-target foils that included novel face and object stimuli, the participant’s own face, their own dog (Experiment 1), and their own car (Experiment 2). The consistent findings across the two experiments were the following: (1) the N250 potential differentiated the target faces and objects from the non-target face and object foils and (2) despite being non-targets, the own face and own objects produced an N250 response that was equal in magnitude to the target faces and objects by the end of the experiment. Thus, as indicated by its response to personally familiar and recently familiarized faces and objects, the N250 component is a sensitive index of individuated representations in visual memory
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