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 24 for “"particle emissions"”.
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A vertically-integrated approach to climate science : from measurements and machine learning to models and policy
The role anthropogenic aerosol particles play in the formation and persistence of ice clouds remains one of the most uncertain aspects of understanding past, present, and future climate. Studying how these particles influence ice cloud formation requires careful measurement of their ice nucleating …
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The mobility of radiocesium and plutonium in Roach Lake in southern Nevada
… separation, by the detection of its alpha particle emissions with surface barrier detectors. Strontium-90 was determined at only one site, after extraction from the samples, by measuring its daughter yttrium-90 with a gas proportional counting instrument.
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Modeling Size-Resolved Particle Number Emissions From Advanced Technology And Alternative Fueled Vehicles In Real-Operating Conditions
Two particle number emission datasets were analyzed in detail. The first data set contained particle number emissions from four transit buses, including two hybrid diesel-electric buses, under a variety of driving conditions and technological/fuel treatments including: diesel oxidation catalysts, …
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Lasermessverfahren zur Bestimmung von Geschwindigkeit und Kraftstoffverteilung bei motorischen Einspritzvorgängen
… i.e. fuel distribution, and for the reduction of particle emissions. It is demonstrated, that the timing of the first injection is directly affecting both the local air fuel ratio and the penetration of the injected fuel. A homogeneous fuel distribution and low cycle-to-cycle variations can be …
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Modeling The Evolution Of Vehicle Exhaust Plume Near Road And In Laboratory Dilution Systems Using The Ctag Model
… structure to generate the processed on-road particle emissions. It implies that roadway and surrounding infrastructure designs can affect near-road air quality. CTAG can be used to improve the regulatory model in assessing the air quality in near-road environments. The turbulent reacting …
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Measurement of particulate matter size, concentration and mass emissions from in-use heavy duty vehicles
… of the PM by virtue of a subsequent reduction in particle size. These ultrafine particles are able to better penetrate the alveolar region where they can cause serious lung disorders. Alternative fuels such as compressed and liquefied natural gas (CNG and LNG) and the synthetic diesel fuel Mossgas …
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3-D Topology Optimization of Spatially Averaged Surface-Enhanced Raman Devices
… (SERS) have predominantly focused on single particle emissions or two-dimensional systems, which are impractical for actual fabrication. An objective function represented by ട|E|⁴dV effectively approximates Raman enhancement. This function tends to diverge near sharp tips and other singular …
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Particle Matter Measurements for Inspection/Maintenance Programs
<p>Particle emissions from Heavy Duty Diesel Vehicles (HDDVs) are currently measured by opacity or dynamometer gravimetric analysis. The Electronic Tailpipe Particle Sensor (ETaPS) is an inexpensive measurement device purported to give real time response to particle mass and was proposed as a …
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The nature of lubricant-derived ash-related emissions and their impact on diesel aftertreatment system performance
… means for meeting increasingly stringent particle emissions regulations. Over time, incombustible material or ash, primarily derived from metallic additives in the engine lubricant, accumulates in the DPF. Ash accumulation leads to increased flow restriction and an associated increase in …
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The effects of secondary air injection on particulate matter emissions
… air injection (SAI) on particulate matter (PM) emissions. SAI was developed to reduce hydrocarbon (HC) emissions and has been shown to be effective as a strategy to reduce HC emissions at cold-start. In general, cold-start emissions have become an increasingly important problem due to new, more …
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Neutron Emission Following Nuclear Muon Capture in Al
… the AlCap collaboration was formed to study particle emissions from μ− + Al-27 → νμ + M g-27. This dissertation will present the results of the neutron emissions from this study, and includes a measurement of the muon lifetime when captured by Al, Ti, and Pb with results of 864 ± 2, 341 ± 1, …
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Individual and synergistic effects of lubricant additive (Ca, Mg, Zn) combinations on ash characteristics and DPF performance
… exhaust in order to meet increasingly strict particle emissions regulations. Diesel exhaust particulates mainly include soot and ash. Soot, carbon particles derived from incomplete fuel combustion, can be oxidized into carbon dioxide after being trapped by the DPF through a catalytic heating …
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Black carbon mixing state in Paris during MEGAPOLI: Connecting particle resolved observation to particle resolved modeling
… and properties of black carbon aerosol particles change continuously after emission during transport in the atmosphere. Coagulation, condensation, and photochemistry are contributing processes, collectively termed aging. Understanding these processes is important for assessing the …
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Passive regeneration : long-term effects on ash characteristics and diesel particulate filter performance
… means for meeting increasingly rigorous particle emissions regulations. There is growing interest to exploit passive regeneration of DPFs to reduce fuel consumption accompanying traditional active regeneration. Incombustible material or ash, mainly derived from metallic additives in the …
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Aufklärung des Einflusses von C7 und C8 Aromaten auf die Partikelbildung im Abgas von Ottomotoren mit Direkteinspritzung sowie Entwicklung eines Screeningverfahrens zur Vorhersage der Partikelbildung
With the introduction of direct injection, particle emissions are the main focus of chemical and technical interest. The aim is to contribute to clarifying the influence of specific substance groups and individual components in gasoline on particle formation and, in particular, to identify the …
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Modeling and interpreting the observed effects of ash on diesel particulate filter performance and regeneration
… means for meeting increasingly stringent particle emissions regulations. Although the soot deposit can be removed by regeneration, the incombustible material - ash, primarily derived from metallic additives in the engine lubricant, accumulates in the DPF channels with the increasing …
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Investigations of ash layer characteristics and ash distribution in a diesel particulate filter using novel lubricant additive tracers
… matter in order to meet increasingly stringent particle emissions regulations. Over time, the DPF slowly accumulates incombustible material or ash, mostly from the metallic additives present in the engine lubricant. This build up of accumulated ash leads to an increase in flow restriction and …
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Measurement of soot precursor particles under atmospheric and low pressure conditions by means of time-of-flight mass spectrometry
… existing models describing the growth of soot particles and the formation of soot aggregates are widely accepted, as well. However, the so-called inception, i.e. the mechanism leading to the formation of the first solid particles from gas phase molecules, is still a controversial issue. This is …
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Interactions Between Dust and Ecosystem, and Landscape at Multiple Scales
… contributor to global aerosols from land. Dust emissions rate and properties are influenced by meteorological conditions, parent soil, and landscape, and in turn, it affects impacts on climate, ecosystems, and human societies through various pathways. This dissertation aims to explore the …
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Experimental Studies of Diesel Particle Filtration
… led to the widespread application of the diesel particle filter (DPF) in engine exhaust systems to limit emissions of combustion-generated particles. The collection of particulate matter in exhaust after-treatment devices depends on a number of mechanisms for aerosol particle deposition that are …
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