Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 70 for “"Cold-start"”.
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Cold-start universal information extraction
… thesis opens up a new research direction called Cold-Start Universal Information Extraction, where the full extraction and analysis starts from scratch and requires little or no prior manual annotation or pre-defined type schema. In addition to this new research paradigm, we also contribute …
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In cylinder liquid fuel visualization during cold start
… (HC) emissions from SI engines during their cold start period. The presence of liquid fuel in the combustion chamber, during a cold start, is believed to contribute significantly to the increased levels. This work uses planar laser induced fluorescence to visualize the development of liquid …
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Effects of charge motion control during cold start of SI engines
… intake charge motion control approaches on the cold start-up process of a port fuel injected SI engine. Engine experiments were performed to assess the effectiveness of enhanced charge motion on mixture preparation, combustion, and hydrocarbon (HC) emissions. Different charge motions were …
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Effects of secondary air injection during cold start of SI engines
The paucity of exhaust oxygen during cold start of automobile SI engines limits the extent of exothermic chemical reactions in the exhaust port, manifold, and catalyst. The injection of air into the exhaust system therefore could be an effective way to utilize additional thermal and chemical energy …
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Cold start fuel management of port-fuel-injected internal combustion engines
… out hydrocarbon concentrations for various cold start strategies. The manufacturer's original fueling strategy is used as a starting point and is compared to a "in-cylinder fuel air ratio (Phi) [approx.] 1" case (a fueling strategy that results in an in-cylinder concentration of …
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The Effects of Increased Ignition Energy on Cold Start Hydrocarbon Emissions
… on the effects of increased ignition energy on cold start hydrocarbon emissions was conducted. The tests were conducted on a single cylinder ASTM-CFR engine. The engine was outfitted with EFI, exhaust analyzers, and temperature probes. The engine was also modified to produce cold start …
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Fully integrated ultra low voltage cold start system for thermal energy harvesting . . .
… However, they often need > 200 mV in order to start up initially. Current solutions for achieving a low voltage start up require the use of bulky off-chip transformers, leading to undesired area overhead. This research work presents proof-of-concept for a fully integrated start-up system, which …
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Cold-start effects on performance and efficiency for vehicle fuel cell systems
… transient known to the automotive community as "cold-start" effects. Cold-start effects play a significant role in power limitations in a fuel cell vehicle, and may require hybridization (batteries) to supplement available power. A fuel cell system model developed as part of this work allows …
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Opposing effects of recirculated gases during cranking on cold start of diesel engines
… EFFECTS OF RECIRCULATED GASES DURING CRANKING ON COLD START OF DIESEL ENGINES</p> <p>by</p> <p>RAFIK ROFAIL</p> <p>August 2011</p> <p>Advisor: Dr. Naeim Henein</p> <p>Major: Mechanical Engineering</p> <p>Degree: Doctor of Philosophy</p> <p>Enhancing cold start of DI diesel engines is the …
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Investigations on the pollutant emissions of gasoline direct injection engines during cold-start
… regimes, creates emissions challenges during the cold crank-start and cold fast-idle phases. The engine cold-start is responsible for a disproportionate share of the hydrocarbons (HC), nitrogen oxides (NOx) and particulate matter (PM) emitted over the certification cycle. Understanding the sources …
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DalSegno: User-centric preference elicitation strategies for mitigating cold start in music recommender systems
… suggestions — an issue known as the new user cold start problem. This problem is exacerbated by the fact that most commercial recommender systems lack transparency and avenues for users to influence their recommendations. We thus propose DalSegno, a music recommender system with an interactive …
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Assessment of the factors influencing PN emission in a DISI engine under cold-start condition
… air-fuel equivalence ratio below which PM starts to form rapidly. The threshold is influenced by the combustion temperature. PM starts to form at lower equivalence ratio when the combustion temperature was lower. Contrary to the PM generated from flame propagation in fuel-rich mixture case, …
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Control strategy for hydrocarbon emissions in turbocharged direct injection spark ignition engines during cold-start
… engines have new emissions challenges during cold start. DISI fuel injection delivers more liquid fuel into the combustion chamber, increasing the emissions of unburned hydrocarbons. The turbocharger slows down activation (warm-up) of the catalytic exhaust after-treatment system. The objective …
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Reducing cold start hydrocarbon emissions from port fuel injected spark ignition engines with improved management of hardware & controls
… performed to investigate strategies for reducing cold start hydrocarbon (HC) emissions from port fuel injected (PFI) spark ignition (SI) engines with better use of existing hardware and control systems. Engine experiments and computer simulations were used for three major phases of the project: …
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Hybrid recommender systems for personalized government-to-business e-services
… suffer from data uncertainty, data sparsity, cold-start item and cold-start user problems, resulting in poor recommendation accuracy and reduced coverage. An effective solution proposed in this research to alleviate such problems is the development of hybrid and fusion-based recommendation …
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Spatio-Temporal Dynamics of Reaction Zones in Catalytic Monolith Reactors
… oxygen storage and release as well as the cold-start behavior of a three-way catalytic converter (TWC). As shown in this work, axial gradients in the temperature and stored oxygen profile cannot be neglected during cold-start, fast lean/rich cycling or sudden and significant changes in the …
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Analysis of various fuels in DISI and PFI engines : separating mixing effects from crevice and quench layer effects
… hydrocarbons (UBHC) in the exhaust during cold start, when the catalytic converter is further away from the engine. The time the catalytic converter takes to heat to an optimum efficiency is longer. UBHC can also accumulate in the cylinder chambers and can be caused by quenching effects or …
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