Engineering Commons^™

Should Tortuosity Still Be Used In Upscaling?, Francisco J. Valdes-Parada, Mark L. Porter, Brian D. Wood

Francisco J. Valdes-Parada

The concept of tortuosity is an integral part of models that describe trans- port in multiscale systems. Traditionally, tortuosity is de#12;ned as the ratio of an e#11;ective path length to the shortest path length in a representative sample of the porous medium microstructure. While the latter can be unambiguously speci#12;ed, the same is not true for the e#11;ective path length, since it changes from one type of transport to another. Consequently, it is possible to have di#11;erent tortuosity values for di#11;erent transport processes taking place in the same system. In order to avoid running into unclear interpretations, we pro- pose …

Hypothetical Thermodynamic Properties. Subcooled Vaporization Enthalpies And Vapor Pressures Of Polyaromatic Heterocycles And Related Compounds

James Chickos

No abstract provided.

Absolute Nitrogen Atom Density Measurements By Two-Photon Laser-Induced Fluorescence Spectroscopy In Atmospheric Pressure Dielectric Barrier Discharges Of Pure Nitrogen, Et-Touhami Es-Sebbar, Christian Sarra-Bournet, Nicolas Naudé, Françoise Massines, Nicolas Gherardi

Dr. Et-touhami Es-sebbar

In this paper, two-photon absorption laser induced fluorescence spectroscopy is used to follow the nitrogen atom density in flowing dielectric barrier discharges fed with pure nitrogen and operating at atmospheric pressure. Two different dielectric barrier discharge regimes are investigated: the Townsend regime, which is homogeneous although operating at atmospheric pressure, and the more common filamentary regime. In both regimes, densities as high as 3x1014 /cm3 are detected. However, the N atoms kinetic formation depends on the discharge regime. The saturation level is reached more rapidly with a filamentary discharge. For a given discharge regime, the N atom density depends strongly …

Contributions To The Development Of The S.E.T.U.P. (Experimental And Theoretical Simulations Useful For Planetology) Project, E. Arzoumanian, C. Romanzin, M-C. Gazeau, Et. Es-Sebbar, A. Jolly, S. Perrier, Y. Benilan

Dr. Et-touhami Es-sebbar

No abstract provided.

Multiwavelength Studies For Titan's Atmospheric Composition Analysis, Y. Benilan, Et. Es-Sebbar, N. Fray, M-C. Gazeau, A. Jolly, M. Schwell, J. Guillemin

Dr. Et-touhami Es-sebbar

Titan's atmosphere mainly made of nitrogen and methane is rich in organic molecules. Hydrocarbons are formed from the photolytic dissociation of CH4 and nitriles are created by dissociation of N2 followed by reactions with hydrocarbons. In order to understand the physicochemical mechanisms responsible for the evolution of Titan's atmosphere, photochemical models are built. The latter need constrains for vertical profiles of organic compounds from the high thermosphere down to the low stratosphere as well as photodissociation rates. Those profiles over the entire atmosphere can be retrieved from Cassini observations, in particular by limb sounding, coupling infrared and ultraviolet spectroscopy. However, …

Vuv Photostability Of Prebiotic Species, M. Schwell, Y. Bénilan, M.-C. Gazeau, N. Fray, A. Jolly, Et. Es-Sebbar, N. Champion, S. Leach, H. W Jochims, H. Baumgärtel, E. Rühl

Dr. Et-touhami Es-sebbar

No abstract provided.

S.E.T.U.P. Experimental And Theoretical Simulations Useful For Planetology- Related Studies In The Frame Of A Program Of Titan’S Atmosphere Laboratory Simulations, M.-C. Gazeau, Et. Es-Sebbar, E. Arzoumanian, C. Romanzin, A. Jolly, S. Perrier, Y. Bénilan

Dr. Et-touhami Es-sebbar

No abstract provided.

Characterization Of An N2 Flowing Microwave Post-Discharge By Oes Spectroscopy And Determination Of Absolute Ground-State Nitrogen Atom Densities By Talif, Et. Es-Sebbar, Y. Benilan, A. Jolly, M-C. Gazeau

Dr. Et-touhami Es-sebbar

A flowing microwave post-discharge source sustained at 2.45 GHz in pure nitrogen has been investigated by optical emission spectroscopy (OES) and two-photon absorption laser-induced fluorescence (TALIF) spectroscopy. Variations of the optical emission along the post-discharge (near, pink and late afterglow) have been studied and the gas temperature has been determined. TALIF spectroscopy has been used in the late afterglow to determine the absolute ground-state nitrogen atomic densities using krypton as a reference gas. Measurements show that the microwave flowing post-discharge is an efficient source of N (4S) atoms in late afterglow. In our experimental conditions, the maximum N (4S) density …

Design And Cfd Analysis Of Mass Transfer And Shear Stresses Distributions In Airlift Reactor, Rachid Bannari, Brahim Selma, Abdelfettah Bannari, Pierre Proulx

Rachid BANNARI

The design, scale-up and performance evaluation of biological reactors require accurate information about the gas-liquid flow dynamics. In this study, we use CFD techniques to investigate important parameters of the multiphase flow dynamics on an initial airlift bioreactor in order to improve its design. Such parameters are distributions of shear stresses and mass transfer. Our initial proposed design of the airlift bioreactor was used for biomass growing. Specifically to produce cellulase enzyme using the fungus Trichoderma Reesei. However, the morphology of the microorganism obtained in this bioreactor was not appropriated to produce cellulase. Since the microorganism morphology presented a small …

Density Of Jatropha Curcas Seed Oil And Its Methyl Esters: Measurement And Estimations, Abdul Aziz Abdul Raman

Abdul Aziz Abdul Raman

Density data as a function of temperature have been measured for Jatropha curcas seed oil, as well as biodiesel jatropha methyl esters at temperatures from above their melting points to 90 ° C. The data obtained were used to validate the method proposed by Spencer and Danner using a modified Rackett equation. The experimental and estimated density values using the modified Rackett equation gave almost identical values with average absolute percent deviations less than 0.03% for the jatropha oil and 0.04% for the jatropha methyl esters. The Janarthanan empirical equation was also employed to predict jatropha biodiesel densities. This equation …

Researches On Copper. History & Metallurgy, Fathi Habashi

Fathi Habashi

Gold. History, Metallurgy, Culture, Fathi Habashi

Fathi Habashi

The Natural Transparency And Piezoelectric Response Of The Greta Oto Butterfly Wing, Valerie R. Binetti, Jessica D. Schiffman, Oren D. Leaffer, Jonathan E. Spanier, Caroline L. Schauer

Jessica D. Schiffman

The Greta oto, or the ‘‘glasswing butterfly’’, is a member of the Ithomiini tribe. Although rare among lepidopteran, the G. oto’s wings are naturally transparent. To understand the material properties of natural transparency, the various structures on the surface of the wings, both the transparent and brown ‘‘veins’’ and wing parameter regions were studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), reflectance spectrometry, transmission spectrometry and scanning probe microscopy (SPM) in order to investigate their local structure, periodic character, and electromechanical response. Nanosized protuberances in a highly ordered array were found on the surface of the transparent part …

Interfacial Fluctuations In An Ideal Block Copolymer Resist, August Bosse, Eric Lin, Ronald Jones, Alamgit Karim

Alamgir Karim

We use field-theoretic computer simulations to show that intrinsic interfacial fluctuations may place limits on the use of block copolymer materials as resists for the nanofabrication of next-generation electronics devices. Even for an ideal system, our simulations demonstrate that the magnitude of the interfacial fluctuations is of the same order as the maximum interfacial roughness requirements noted in the International Technology Roadmap for Semiconductors. Furthermore, we show that the interfacial fluctuations exhibit an inverse power law dependence on the copolymer molecular mass, and we identify a peak in the interfacial fluctuation spectrum indicative of fluctuations with a wavelength of order …

Soot Oxidation, J. S. Lighty, V. Romano, A. F. Sarofim

JoAnn S. Lighty

Capillary Instability In Nanoimprinted Polymer Films, Kyle J. Alvine, Yifu Ding, Jack F. Douglas, Hyun Wook Ro, Brian C. Ockerberg, Alamgir Karim, Christopher L. Soles

Alamgir Karim

Capillary forces play an active role in defining the equilibrium structure of nanoscale patterns. This effect can be especially pronounced in soft materials such as polymers near or above their glass transition temperature (Tg) where material flow is possible. In these situations, the effect of surface tension can produce varied and complex capillary instabilities, even in relatively simple geometries such as parallel-line-space grating patterns. Here we investigate a novel capillary instability that arises upon thermal annealing of nanoimprinted polystyrene line-space gratings with an underlying residual layer. This novel instability is characterized by the development of lateral undulations of the lines, …

Assessment Of The Impact Of The European Co2 Emissions Trading Scheme On The Portuguese Chemical Industry, João F. Gomes

João F Gomes

No abstract provided.

A Study On Thermal Combustion Of Lean Methane–Air Mixtures: Simplified Reaction Mechanism And Kinetic Equations, Krzysztof Gosiewski, Anna Pawlaczyk, Krzysztof Warmuzinski, Manfred Jaschik

Krzysztof Gosiewski

Homogeneous combustion of lean methane–air mixtures occurs in both thermal and catalytic reverse-flow reactors. The modeling and design of such reactor requires a reliable and relatively simple kinetic model of the combustion. Although a number of detailed descriptions of the kinetics of homogeneous combustion are available in the literature (including those which take into account complex free-radical reactions), their practical usefulness is doubtful. In the present study a simple one- or two-stage model is proposed which directly describes global kinetics and neglects intermediates and radicals. Special attention is paid to the mechanism of the possible formation of carbon monoxide. The …

Structure Studies On Nanocrystalline Powder Of Mgo Xerogel Prepared By Sol-Gel Method, Grzegorz Dercz, Krystian Prusik, L. Pajak, Roman Pielaszek, Janusz J. Malinowski, Wojciech Pudło

Janusz J. Malinowski

Nanocrystalline Mgo Powder Materials Prepared By Sol-Gel Studied By X-Ray Diffraction And Electron Microscopy, G. Dercz, L Pajak, K. Prusik, R Pielaszek, Janusz J. Malinowski

Janusz J. Malinowski

The Development Of Humans – A Study Including Languages, Cultures, Religions And Genetics, Dr. Erik Dahlquist, Dr. Allan Dahlquist

Dr. Erik Dahlquist

The book covers the development of culture, religion, language and genetics of the human population since prehistory. Four main cultures have spread around the globe: 1) Monosyllabic language people with ancestor cult 2) Austroasiatic people with sun worshipping and megalit graves. Counting with 20 as the base 3) Uralic speaking people with kings from the sky, and strong city states. Moon and mother godess. Don´t differentiate between male and female, he and she. 4) Inflectual language speaking people with sky gods and cattles. Indoeuropeans. Often endings differentiating he and she. Shows how original cultures are refelected in todays society.

Effects Of Ultrasound In Coating Nano‐Precipitated Caco3 With Stearic Acid, Abdul Aziz Abdul Raman

Abdul Aziz Abdul Raman

Nano-Precipitated CaCO3 (NPCC) are coated with stearic acid to improve its dispersion in polymer as well as to reduce agglomeration. In this work, coating was done by wet method using ethanol. Ultrasonication was applied to NPCC to de-agglomerate micron size NPCC into smaller size. Effects of amplitude, temperature and energy input of ultrasonication was investigated. The amplitude was varied from 60% to 100% whereas temperature was varied from 5 ◦C to 45◦C. The energy input was stressed up from 3.6 kJ to 180 kJ. Mean diameter of NPCC were observed by using Particle Size Analyzer and Transmission Electron Microscopy (TEM). …

Synthesis, Characterization And Application Of Al,Fe-Pillared Clays, Zeljko D. Cupic

Zeljko D Cupic

No abstract provided.