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Full-Text Articles in Mechanical Engineering

Thermal Removal Of Carbon Dioxide From The Atmosphere: Energy Requirements And Scaling Issues, Ted Von Hippel Aug 2019

Thermal Removal Of Carbon Dioxide From The Atmosphere: Energy Requirements And Scaling Issues, Ted Von Hippel

Ted von Hippel

I conduct a systems-level study of direct air capture of CO2 using techniques from thermal physics. This system relies on a combination of an efficient heat exchanger, radiative cooling, and refrigeration, all at industrial scale and operated in environments at low ambient temperatures. While technological developments will be required for such a system to operate efficiently, those developments rest on a long history of refrigeration expertise and technology, and they can be developed and tested at modest scale. I estimate that the energy required to remove CO2 via this approach is comparable to direct air capture by other techniques. The ...


The Impact Of Trees On Passive Survivability During Extreme Heat Events In Warm And Humid Regions, Ulrike Passe, Janette R. Thompson, Baskar Ganapathysubramanian, Boshun Gao, Breanna L. Marmur Apr 2019

The Impact Of Trees On Passive Survivability During Extreme Heat Events In Warm And Humid Regions, Ulrike Passe, Janette R. Thompson, Baskar Ganapathysubramanian, Boshun Gao, Breanna L. Marmur

Breanna L. Marmur

Communities are increasingly affected by excessive heat. The likelihood of extreme heat events is predicted to increase in the Midwest region of the United States. By mid-century (2036–2065), one year out of 10 is projected to have a 5-day period that is 13°F warmer than a comparable earlier period (1976–2005). The frequency of high humidity/dew point days (“extra moist tropical air mass days,” MT++ synoptic climate classification system) has also increased significantly during a similar period (1975–2010) and between 2010 and 2014 included 8 of 26 heat events. This impact is exacerbated by the fact ...


Call For Abstracts - Resrb 2019, July 8-9, Wrocław, Poland, Wojciech M. Budzianowski Dec 2018

Call For Abstracts - Resrb 2019, July 8-9, Wrocław, Poland, Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.


2018-19 Tla Application - Thermal Fluid Sequence, M. A. Rafe Biswas Jul 2018

2018-19 Tla Application - Thermal Fluid Sequence, M. A. Rafe Biswas

M. A. Rafe Biswas

No abstract provided.


Dynamical Thermal Conductivity Of Suspended Graphene Ribbons In The Hydrodynamic Regime, Zlatan Aksamija, Arnab K. Majee Jul 2018

Dynamical Thermal Conductivity Of Suspended Graphene Ribbons In The Hydrodynamic Regime, Zlatan Aksamija, Arnab K. Majee

Zlatan Aksamija

The steady-state behavior of thermal transport in bulk and nanostructured semiconductors has been widely
studied, both theoretically and experimentally. On the other hand, fast transients and frequency dynamics of
thermal conduction has been given less attention. The frequency response of thermal conductivity has become
more crucial in recent years, especially in light of the constant rise in the clock frequencies in microprocessors
and terahertz sensing applications. Thermal conductivity in response to a time-varying temperature field starts
decaying when the frequency exceeds a cutoff frequency Omega_c, which is related to the inverse of phonon relaxation time τ, on the order of ...


(Magneto)Caloric Refrigeration: Is There Light At The End Of The Tunnel?, Vitalij K. Pecharsky, Jun Cui, Duane D. Johnson Feb 2018

(Magneto)Caloric Refrigeration: Is There Light At The End Of The Tunnel?, Vitalij K. Pecharsky, Jun Cui, Duane D. Johnson

Duane D. Johnson

Caloric cooling and heat pumping rely on reversible thermal effects triggered in solids by magnetic, electric or stress fields. In the recent past, there have been several successful demonstrations of using first-order phase transition materials in laboratory cooling devices based on both the giant magnetocaloric and elastocaloric effects. All such materials exhibit non-equilibrium behaviours when driven through phase transformations by corresponding fields. Common wisdom is that non-equilibrium states should be avoided; yet, as we show using a model material exhibiting a giant magnetocaloric effect, non-equilibrium phase-separated states offer a unique opportunity to achieve uncommonly large caloric effects by very small ...


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Induction Heating Of Thin Films, Paul L. Bergstrom, Melissa L. Trombley Aug 2017

Induction Heating Of Thin Films, Paul L. Bergstrom, Melissa L. Trombley

Paul Bergstrom

A method of performing regional heating of a system having a substrate. The method may include applying a thin film to the system, and controllably energizing a coil positioned near the thin film. The energized coils thereby generate a magnetic flux. The method further includes inducing a current in the thin film with the magnetic flux thereby heating the system.


Presentation Of Double Inlet Scpp, Nima Fathi, Seyed Sobhan Aleyasin, Patrick Wayne, Peter Vorobieff Jul 2017

Presentation Of Double Inlet Scpp, Nima Fathi, Seyed Sobhan Aleyasin, Patrick Wayne, Peter Vorobieff

Nima Fathi

No abstract provided.


Us Patent 9,702,573: Nested Heat Transfer System, Sanza Kazadi Jul 2017

Us Patent 9,702,573: Nested Heat Transfer System, Sanza Kazadi

Sanza Kazadi

A novel nested heat transfer system comprises a plurality of chained enhanced entrochemical cells with nested structures. Each enhanced entrochemical cell includes a first chamber containing desiccant, or a higher concentration solution, and a second chamber containing refrigerant,   or   a   lower   concentration   solution.   Preferably,   the   first   chamber   and   the   second   chamber   are   connected   by   a   conduit.  Furthermore,   a   smaller   chamber   in   an   enhanced   entrochemical   cell   is   encapsulated   by   a   larger   chamber   in   an   adjacent   enhanced entrochemical cell, thus forming a nested structure between the two enhanced entrochemical cells. A chain of enhanced entrochemical cells with a plurality of such nested ...


Simple Tester For Measuring Lateral Thermal Diffusivities In Composites, Stephen D. Holland, Elizabeth Gregory, Daniel Romero Jun 2017

Simple Tester For Measuring Lateral Thermal Diffusivities In Composites, Stephen D. Holland, Elizabeth Gregory, Daniel Romero

Stephen D. Holland

Model-based analysis and inversion of thermography data relies on knowledge of thermal diffusivities. Through-thickness diffusivity is readily measured using the flash method [1]. In composite materials, lateral diffusivities may be drastically different from the through-thickness values, but there is no comparable simple and standard approach for measuring those lateral thermal diffusivities. Welch, Heath, and Winfree [2] proposed a technique based on laser line pulse excitation, but that approach requires a reasonably powerful laser and thermal camera with the concomitant costs and safety requirements. In this presentation, we show a simple and low cost (but not entirely nondestructive) system and method ...


Adhesion Hysteresis And Its Role In Vibrothermography Crack Heating, Bryan E. Schiefelbein, Tyler Lesthaeghe, Ashraf F. Bastawros, Stephen D. Holland Jun 2017

Adhesion Hysteresis And Its Role In Vibrothermography Crack Heating, Bryan E. Schiefelbein, Tyler Lesthaeghe, Ashraf F. Bastawros, Stephen D. Holland

Stephen D. Holland

Vibrothermography is an NDE inspection which uses vibration to stimulate surface cracks and measure the resultant heat generation. For years, the accepted assumption has been that heat generation in Vibrothermography NDE is due to friction between opposing crack surfaces [1–3]. A frictional mechanism suggests that crack surfaces in sliding shear would generate heat, whereas crack surfaces coming into and out of contact in an opening-closing mode would not, or would generate much less. But cracks heat easily in opening/closing mode and experimental evidence [4] is not consistent with the prediction that heat generation for shear vibration should be ...


Effects Of Temperature Change On Interfacial Delamination In Thermal Barrier Coatings, Hossein Ebrahimi, Soheil Nakhodchi Apr 2015

Effects Of Temperature Change On Interfacial Delamination In Thermal Barrier Coatings, Hossein Ebrahimi, Soheil Nakhodchi

Hossein Ebrahimi

No abstract provided.


La0.7Sr0.3Fe0.7Ga0.3O3-Δ As Electrode Material For A Symmetrical Solid Oxide Fuel Cell, Zhibin Yang, Yu Chen, Chao Jin, Guoliang Xiao, Minfang Han, Fanglin Chen Mar 2015

La0.7Sr0.3Fe0.7Ga0.3O3-Δ As Electrode Material For A Symmetrical Solid Oxide Fuel Cell, Zhibin Yang, Yu Chen, Chao Jin, Guoliang Xiao, Minfang Han, Fanglin Chen

Fanglin Chen

In this research, La0.7Sr0.3Fe0.7Ga0.3O3−δ (LSFG) perovskite oxide was successfully prepared using a microwave-assisted combustion method, and employed as both anode and cathode in symmetrical solid oxide fuel cells. A maximum power density of 489 mW cm−2 was achieved at 800 °C with wet H2 as the fuel and ambient air as the oxidant in a single cell with the configuration LSFG|La0.8Sr0.2Ga0.83Mg0.17O3−δ|LSFG. Furthermore, the cells demonstrated good stability in ...


A Turbulence Model For The Heat Transfer Near Stagnation Point Of A Circular Cylinder, Mounir B. Ibrahim Feb 2015

A Turbulence Model For The Heat Transfer Near Stagnation Point Of A Circular Cylinder, Mounir B. Ibrahim

Mounir B. Ibrahim

A one-equation low-Reynolds number turbulence model has been applied successfully to the flow and heat transfer over a circular cylinder in turbulent cross flow. The turbulence length-scale was found to be equal 3.7y up to a distance 0.05δ and then constant equal to 0.185δ up to the edge of the boundary layer (wherey is the distance from the surface and δ is the boundary layer thickness). The model predictions for heat transfer coefficient, skin friction factor, velocity and kinetic energy profiles were in good agreement with the data. The model was applied for Re ≤250,000 and ...


Zespół Energii Odnawialnej I Zrównoważonego Rozwoju (Eozr), Wojciech M. Budzianowski Dec 2014

Zespół Energii Odnawialnej I Zrównoważonego Rozwoju (Eozr), Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.


Thermodynamic Analysis Of Separation Systems, Y. Demirel Jul 2014

Thermodynamic Analysis Of Separation Systems, Y. Demirel

YASAR DEMIREL

Separation systems mainly involve interfacial mass and heat transfer as well as mixing. Distillation is a major separation system by means of heat supplied from a higher temperature level at the reboiler and rejected in the condenser at a lower temperature level. Therefore, it resembles a heat engine producing a separation work with a rather low efficiency. Lost work (energy) in separation systems is due to irreversible processes of heat, mass transfer, and mixing, and is directly related to entropy production according to the Gouy-Stodola principle. In many separation systems of absorption, desorption, extraction, and membrane separation, the major irreversibility ...


Measurement Of The Rate Of Hydrogen Peroxide Thermal Decomposition In A Shock Tube Using Quantum Cascade Laser Absorption Near 7.7 Μm, M. B. Sajid, Et. Es-Sebbar, T. Javed, C. Fittschen, A. Farooq May 2014

Measurement Of The Rate Of Hydrogen Peroxide Thermal Decomposition In A Shock Tube Using Quantum Cascade Laser Absorption Near 7.7 Μm, M. B. Sajid, Et. Es-Sebbar, T. Javed, C. Fittschen, A. Farooq

Dr. Et-touhami Es-sebbar

Hydrogen peroxide (H2O2) is formed during hydrocarbon combustion and controls the system reactivity under intermediate temperature conditions. Here, we measured the rate of hydrogen peroxide decomposition behind reflected shock waves using midinfrared absorption of H2O2 near 7.7 µm. We performed the experiments in diluted H2O2/Ar mixtures between 930 and 1235 K and at three different pressures (1, 2, and 10 atm). Under these conditions, the decay of hydrogen peroxide is sensitive only to the decomposition reaction rate, H2O2 + M → 2OH + M (k1). The second-order rate coefficient at low pressures (1 and 2 atm) did not exhibit any pressure ...


A Case Study Of Heat Treatment On Aisi 1020 Steel, Sayed Shafayat Hossain, Md. Maksudul Islam, Md. Sajibul Alam Bhuyan Dec 2013

A Case Study Of Heat Treatment On Aisi 1020 Steel, Sayed Shafayat Hossain, Md. Maksudul Islam, Md. Sajibul Alam Bhuyan

Md. Maksudul Islam

Proper heat treatment of steels is one of the most important factors in determining how they will perform in service. Engineering materials, mostly steel, are heat treated under controlled sequence of heating and cooling to alter their physical and mechanical properties to meet desired engineering applications. In this study we have chosen AISI 1020 steel as for our research work and we have tried to find out the mechanical properties (hardness) and micro structural properties (martensite formation, carbon self-locking region) by means of appropriate heat treatment process (annealing, normalizing & hardening). Here the steel specimens were heat treated in a furnace at different temperature levels and soaking time; and then cooled in various media (air, ash, water). After that ...


An Experimental And Modeling Study Of Formaldehyde And 1,3,5-Trioxane Flame Chemistry, Jeffrey S. Santner, Francis M. Haas, Frederick L. Dryer, Yiguang Ju Sep 2013

An Experimental And Modeling Study Of Formaldehyde And 1,3,5-Trioxane Flame Chemistry, Jeffrey S. Santner, Francis M. Haas, Frederick L. Dryer, Yiguang Ju

Francis (Mac) Haas

Formaldehyde is a key species produced during oxidation of virtually all hydrocarbon and oxygenated fuels, and it is also a regulated hazardous air pollutant. An improved understanding of its formation and destruction chemistry is therefore vital to the study of many energy conversion processes. To this end, this work experimentally and numerically investigates the flame chemistry of formaldehyde (CH2O) at atmospheric pressure. The laminar burning rate of 1,3,5-trioxane/O2/N2 mixtures is measured in outwardly propagating spherical flames, where high concentrations of formaldehyde are generated early in the flame structure from decomposition of 1,3,5-trioxane.
Though laminar ...


Evaluation Of Thermal Radiation Effects On Apparent Propagation Rates Of High Pressure Spherical Flames, Jeffrey S. Santner, Francis M. Haas, Yiguang Ju, Frederick L. Dryer Sep 2013

Evaluation Of Thermal Radiation Effects On Apparent Propagation Rates Of High Pressure Spherical Flames, Jeffrey S. Santner, Francis M. Haas, Yiguang Ju, Frederick L. Dryer

Francis (Mac) Haas

Thermal radiation is usually not considered in the interpretation of laminar burning rates measured by the outwardly propagating spherical flame method. However, it may contribute significantly to measurement uncertainty, especially for model-constraining conditions at lower flame temperatures and higher pressures. The present work derives a conservative analytical estimate of the effects of radiation heat loss, which include radiation-induced burned gas motion, decreasing flame temperature due to conduction to the radiating burned gas, and radiation loss from the flame zone. Detailed numerical simulations covering a range of burning conditions serve to validate this analytical tool. Modeling results from both detailed simulation ...


Measurements Of Nh3 Linestrengths And Collisional Broadening Coefficients In N2, O2, Co2, And H2o Near 1103.46 Cm−1, Kyle Owen, Et-Touhami Es-Sebbar, Aamir Farooq Feb 2013

Measurements Of Nh3 Linestrengths And Collisional Broadening Coefficients In N2, O2, Co2, And H2o Near 1103.46 Cm−1, Kyle Owen, Et-Touhami Es-Sebbar, Aamir Farooq

Dr. Et-touhami Es-sebbar

Laser-based ammonia gas sensors have useful applications in many fields including combustion, atmospheric monitoring, and medical diagnostics. Calibration-free trace gas sensors require the spectroscopic parameters including linestrengths and collisional broadening coefficients to be known. Ammonia's strong ν2 vibrational band between View the MathML source has the high absorption strength needed for sensing small concentrations. Within this band, the 1103.46 cm−1 feature is one of the strongest and has minimal interference from CO2 and H2O. However, the six rotational transitions that make up this feature have not been studied previously with absorption spectroscopy due to their small line ...


Effects Of N2o And O2 Addition To Nitrogen Townsend Dielectric Barrier Discharges At Atmospheric Pressure On The Absolute Ground-State Atomic Nitrogen Density, Et. Es-Sebbar, N. Gherardi, F. Massines Jan 2013

Effects Of N2o And O2 Addition To Nitrogen Townsend Dielectric Barrier Discharges At Atmospheric Pressure On The Absolute Ground-State Atomic Nitrogen Density, Et. Es-Sebbar, N. Gherardi, F. Massines

Dr. Et-touhami Es-sebbar

Absolute ground-state density of nitrogen atoms N (2p3 4S3/2) in non-equilibrium Townsend dielectric barrier discharges (TDBDs) at atmospheric pressure sustained in N2/N2O and N2/O2 gas mixtures has been measured using Two-photon absorption laser-induced fluorescence (TALIF) spectroscopy. The quantitative measurements have been obtained by TALIF calibration using krypton as a reference gas. We previously reported that the maximum of N (2p3 4S3/2) atom density is around 3 × 1014 cm−3 in pure nitrogen TDBD, and that this maximum depends strongly on the mean energy dissipated in the gas. In the two gas mixtures studied here, results show ...


Laminar Natural Convection From Isothermal Vertical Cylinders: Revisiting A Classical Subject, Jerod Day, Matthew Zemler, Matthew Traum, Sandra Boetcher Dec 2012

Laminar Natural Convection From Isothermal Vertical Cylinders: Revisiting A Classical Subject, Jerod Day, Matthew Zemler, Matthew Traum, Sandra Boetcher

Sandra Boetcher

No abstract provided.


Determination Of Kinetic Parameters From The Thermogravimetric Data Set Of Biomass Samples, Karol Postawa, Wojciech M. Budzianowski Dec 2012

Determination Of Kinetic Parameters From The Thermogravimetric Data Set Of Biomass Samples, Karol Postawa, Wojciech M. Budzianowski

Wojciech Budzianowski

This article describes methods of the determination of kinetic parameters from the thermogravimetric data set of biomass samples. It presents the methodology of the research, description of the needed equipment, and the method of analysis of thermogravimetric data. It describes both methodology of obtaining quantitative data such as kinetic parameters as well as of obtaining qualitative data like the composition of biomass. The study is focused mainly on plant biomass because it is easy in harvesting and preparation. Methodology is shown on the sample containing corn stover which is subsequently pyrolysed. The investigated sample show the kinetic of first order ...


Temperature-Dependent Absorption Cross-Section Measurements Of 1-Butene (1-C4h8) In Vuv And Ir, Et-Touhami Es-Sebbar, Yves Benilan, Aamir Farooq Dec 2012

Temperature-Dependent Absorption Cross-Section Measurements Of 1-Butene (1-C4h8) In Vuv And Ir, Et-Touhami Es-Sebbar, Yves Benilan, Aamir Farooq

Dr. Et-touhami Es-sebbar

Vacuum ultraviolet (VUV) and infrared (IR) absorption cross-section measurements of 1-butene (1-C4H8; CH2=CHCH2CH3; Butylene) are reported over the temperature range of 296–529 K. The VUV measurements are performed between 115 and 205 nm using synchrotron radiation as a tunable VUV light source. Fourier Transform Infrared (FTIR) spectroscopy is employed to measure absorption cross-section and band strengths in the IR region between 1.54 and 25 μm (∼6500–400 cm−1). The measured room-temperature VUV and IR absorption cross-sections are compared with available literature data and are found to be in good agreement. The oscillator strength for the electronic ...


تمرين سري اول, Dr Alireza Zolfaghari Sep 2012

تمرين سري اول, Dr Alireza Zolfaghari

Dr Alireza Zolfaghari

No abstract provided.


Heat Transfer In A Thin Liquid Film In The Presence Of Electric Field For Non-Isothermal Interfacial Condition, Rama S.R. Gorla, Jorge E. Gatica, Bahman Ghorashi, Pijarn In-Eure, Larry W. Byrd Aug 2012

Heat Transfer In A Thin Liquid Film In The Presence Of Electric Field For Non-Isothermal Interfacial Condition, Rama S.R. Gorla, Jorge E. Gatica, Bahman Ghorashi, Pijarn In-Eure, Larry W. Byrd

Rama S.R. Gorla

Heat transfer enhancement in an evaporating thin liquid film using the electric field under non-isothermal interfacial condition is presented. A new mathematical model subjected to van der Waals attractive forces, the capillary pressure and the electric field is developed to describe the heat transfer enhancement in the evaporating thin liquid film. The effect of an electrostatic field on the curvature of the thin film, evaporative flux, pressure gradient distribution, heat flux, and heat transfer coefficient in the thin film is presented. The results show that the electric field can enhance heat transfer in the thin liquid film significantly. In addition ...


Capacitively Coupled Radio-Frequency Discharges In Nitrogen At Low Pressures, L. L Alves, L. Marques, C. D Pintassilgo, W. Wattieaux, Et. Es-Sebbar, J. Berndt, E. Kovačević, N. Carrasco, L. Boufendi, G. Cernogora Jul 2012

Capacitively Coupled Radio-Frequency Discharges In Nitrogen At Low Pressures, L. L Alves, L. Marques, C. D Pintassilgo, W. Wattieaux, Et. Es-Sebbar, J. Berndt, E. Kovačević, N. Carrasco, L. Boufendi, G. Cernogora

Dr. Et-touhami Es-sebbar

This paper uses experiments and modelling to study capacitively coupled radio-frequency (rf) discharges in pure nitrogen, at 13.56 MHz frequency, 0.1–1 mbar pressures and 2–30 W coupled powers. Experiments performed on two similar (not twin) setups, existing in the LATMOS and the GREMI laboratories, include electrical and optical emission spectroscopy (OES) measurements. Electrical measurements give the rf-applied and the direct-current-self-bias voltages, the effective power coupled to the plasma and the average electron density. OES diagnostics measure the intensities of radiative transitions with the nitrogen second-positive and first-negative systems, and with the 811.5 nm atomic line ...


Ionization Photophysics And Rydberg Spectroscopy Of Diacetylene, M. Schwell, Y. Benilan, N.. Fray, M.-C. Gazeau, Et. Es-Sebbar, F.-G. Levrel, N. Campion, S. Leach Jun 2012

Ionization Photophysics And Rydberg Spectroscopy Of Diacetylene, M. Schwell, Y. Benilan, N.. Fray, M.-C. Gazeau, Et. Es-Sebbar, F.-G. Levrel, N. Campion, S. Leach

Dr. Et-touhami Es-sebbar

Photoionization of diacetylene was studied using synchrotron radiation over the range 8–24 eV, with photoelectron-photoion coincidence (PEPICO) and threshold photoelectron–photoion coincidence (TPEPICO) techniques. Mass spectra, ion yields, total and partial ionization cross-sections were measured. The adiabatic ionization energy of diacetylene was determined as IEad = (10.17 ± 0.01) eV, and the appearance energy of the principal fragment ion C4H+ as AE = (16.15 ± 0.03) eV. Calculated appearance energies of other fragment ions were used to infer aspects of dissociation pathways forming the weaker fragment ions , C3H+, and C2H+. Structured autoionization features observed in the PEPICO spectrum of ...