937 research outputs found
Reading: Amit Majmudar
No full textBecause of COVID-19 this event is canceled.
Amit Majmudar, a multi-genre author and translator, offers a Sacred Arts Festival reading that explores the concept of Building Bridges.
Co-sponsored by the Department of English and the Sacred Arts Festival
Two-stage Fuel Direct Injection in a Diesel Fuelled HCCI Engine
No full textTwo-stage fuel direct injection (DI) has the potential to expand the operating region and control the autoignition timing in a Diesel fuelled homogeneous charge compression ignition (HCCI) engine. In this work, to investigate the dual-injection HCCI combustion, a stochastic reactor model, based on a probability density function (PDF) approach, is utilized. A new wall-impingement sub-model is incorporated into the stochastic spray model for direct injection. The model is then validated against measurements for combustion parameters and emissions carried out on a four stroke HCCI engine. The initial results of our numerical simulation reveal that the two-stage injection is capable of triggering the charge ignition on account of locally rich fuel parcels under certain operating conditions, and consequently extending the HCCI operating range. Furthermore, both simulated and experimental results on the effect of second injection timing on combustion indicate that there exists an optimal second injection timing to gain maximum engine output work for a given fuel split ratio.기계공학전
Analysis of the HCCI Combustion of a Turbocharged Truck Engine Using a Stochastic Reactor Model
No full textHomogeneous Charge Compression Ignition (HCCI) engines arouse great interest due to their high thermal efficiency and very low emissions of nitrogen oxides (NOx) and particulates. Critical issue of the HCCI combustion is the control of the engine since the combustion process is mostly dominated by chemical kinetics. Therefore the accurate assessment of the chemical kinetic is fundamental in numerical simulation of this kind of engines. Experimentally it has been demonstrated that even in HCCI engine the charge within the cylinder is not fully homogeneous, but many quantities, such as temperature, density and equivalence ratio, vary along the combustion chamber. These inhomogeneities influence the combustion process and yield the homogeneous reactor model to be not completely adequate to simulate HCCI combustion. This paper focuses on the use of a stochastic rector model in order to account for temperature inhomogeneities in the numerical simulation of the HCCI combustion. Moreover, the chemical kinetic code has been coupled to GT – Power Code, a 1-D fluid – dynamics code, in order to accurately simulate the operation of a turbocharged truck engine
Studying the Influence of Direct Injection on PCCI Combustion and Emissions at Engine Idle Condition Using Two Dimensional CFD and Stochastic Reactor Model
No full textThis work has been partially funded by Aramco Overseas Company B.V., contract number 6600014846, and by the EPSRC (Engineering and Physical Sciences Research Council), UK, grant number EP/D068703/1
Exploring young students creativity: The effect of model eliciting activities
No full textThe aim of this paper is to show how engaging students in real-life mathematical situations can stimulate their mathematical creative thinking. We analyzed the mathematical modeling of two girls, aged 10 and 13 years, as they worked on an authentic task involving the selection of a track team. The girls displayed several modeling cycles that revealed their thinking processes, as well as cognitive and affective features that may serve as the foundation for a methodology that uses model-eliciting activities to promote the mathematical creative process
sj-pdf-1-jcb-10.1177_0271678X231162648 - Supplemental material for Gut microbiota-associated metabolites and risk of ischemic stroke in REGARDS
No full textSupplemental material, sj-pdf-1-jcb-10.1177_0271678X231162648 for Gut microbiota-associated metabolites and risk of ischemic stroke in REGARDS by Zsuzsanna Ament, Amit Patki, Varun M Bhave, Ninad S Chaudhary, Ana-Lucia Garcia Guarniz, Naruchorn Kijpaisalratana, Suzanne E Judd, Mary Cushman, D Leann Long, M Ryan Irvin and W Taylor Kimberly in Journal of Cerebral Blood Flow & Metabolism</p
Modelling a Dual-fuelled Multi-cylinder HCCI Engine Using a PDF based Engine Cycle Simulator
No full textOperating the HCCI engine with dual fuels with a large difference in auto-ignition characteristics (octane number) is one way to control the HCCI operation. The effect of octane number on combustion, emissions and engine performance in a 6 cylinder SCANIA truck engine, fuelled with n-heptane and isooctane, and running in HCCI mode, are investigated numerically and compared with measurements taken from Olsson et al. [SAE 2000-01-2867]. To correctly simulate the HCCI engine operation, we implement a probability density function (PDF) based stochastic reactor model (including detailed chemical kinetics and accounting for inhomogeneities in composition and temperature) coupled with GT-POWER, a 1-D fluid dynamics based engine cycle simulator. Such a coupling proves to be ideal for the understanding of the combustion phenomenon as well as the gas dynamics processes intrinsic to the engine cycle. The convective heat transfer in the engine cylinder is modeled as a stochastic jump process and accounts for the fluctuations and fluid-wall interaction effects. Curl's coalescence-dispersion model is used to describe turbulent mixing. A good agreement is observed between the predicted values and measurements for in-cylinder pressure, auto-ignition timing and CO, HC as well as NOx emissions for the base case. The advanced PDF-based engine cycle simulator clearly outperforms the widely used homogeneous model based full cycle engine simulator. The trends in combustion characteristics such as ignition crank angle degree and combustion duration with respect to varying octane numbers are predicted well as compared to measurements. The integrated model provides reliable predictions for in-cylinder temperature, CO, HC as well as NOx emissions over a wide range of octane numbers studied
Reviewing the Author-Function in the Age of Wikipedia
No full textIn Reviewing the Author-Function in the Age of Wikipedia, Amit Ray and Erhardt Graeff examine how wiki technology challenges traditional concepts of authorship and authority in knowledge production. The authors build on poststructuralist theory, particularly Roland Barthes\u27s Death of the Author and Michel Foucault\u27s concept of the author-function, to analyze how wikis destabilize individual authorship in favor of collaborative, community-driven content creation.
The essay argues that wikis represent a fundamental shift from the Romantic notion of the solitary author-genius to what they term the wiki writing process —a dynamic system where traditional roles of reader, writer, and editor blur into a unified community of users. Using Wikipedia as a primary case study, the authors demonstrate how the platform\u27s structure (article, discussion, and history pages) creates a digital palimpsest that archives all contributions while enabling continuous revision.
Through analysis of Wikipedia\u27s editing patterns and community oversight mechanisms, Ray and Graeff show how wikis embody poststructuralist principles in practice, creating what they call serial collaborations that exist in perpetual flux. The authors conclude that wikis represent an evolved form of textual production that realizes Foucault\u27s vision of discourse freed from traditional authorial constraints, offering new possibilities for collaborative knowledge creation while challenging established notions of intellectual authority and ownership
The Architecture of India
No full textBook review of "India: Modern Architecture in History" and author interview with Peter Scriver and Amit Srivastav
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