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Full-Text Articles in Engineering

Thermotropic Phase Boundaries In Classic Ferroelectrics, Tom T. A. Lummen, Yijia Gu, Jianjun Wang Jan 2019

Thermotropic Phase Boundaries In Classic Ferroelectrics, Tom T. A. Lummen, Yijia Gu, Jianjun Wang

Yijia Gu

High-performance piezoelectrics are lead-based solid solutions that exhibit a so-called morphotropic phase boundary, which separates two competing phases as a function of chemical composition; as a consequence, an intermediate low-symmetry phase with a strong piezoelectric effect arises. In search for environmentally sustainable lead-free alternatives that exhibit analogous characteristics, we use a network of competing domains to create similar conditions across thermal inter-ferroelectric transitions in simple, lead-free ferroelectrics such as BaTiO3 and KNbO3. Here we report the experimental observation of thermotropic phase boundaries in these classic ferroelectrics, through direct imaging of low-symmetry intermediate phases that exhibit large enhancements in ...


Field-Scale Multi-Phase Lnapl Remediation: Validating A New Computational Framework Against Sequential Field Pilot Trials, Kaveh Sookhak Lari, Colin Johnson, John Rayner, Greg Davis Jan 2018

Field-Scale Multi-Phase Lnapl Remediation: Validating A New Computational Framework Against Sequential Field Pilot Trials, Kaveh Sookhak Lari, Colin Johnson, John Rayner, Greg Davis

ECU Publications Post 2013

Remediation of subsurface systems, including groundwater, soil and soil gas, contaminated with light non-aqueous phase liquids (LNAPLs) is challenging. Field-scale pilot trials of multi-phase remediation were undertaken at a site to determine the effectiveness of recovery options. Sequential LNAPL skimming and vacuum-enhanced skimming, with and without water table drawdown were trialled over 78 days; in total extracting over 5 m3 of LNAPL. For the first time, a multi-component simulation framework (including the multi-phase multi-component code TMVOC-MP and processing codes) was developed and applied to simulate the broad range of multi-phase remediation and recovery methods used in the field trials ...


Reference Data Set Of Volcanic Ash Physicochemical And Optical Properties, A. Vogel, S. Diplas, A. J. Durant, A. S. Azar, M. F. Sunding, William I. Rose, A. Sytchkova, C. Bonadonna, K. Krüger, A. Stohl Oct 2017

Reference Data Set Of Volcanic Ash Physicochemical And Optical Properties, A. Vogel, S. Diplas, A. J. Durant, A. S. Azar, M. F. Sunding, William I. Rose, A. Sytchkova, C. Bonadonna, K. Krüger, A. Stohl

William I. Rose

Uncertainty in the physicochemical and optical properties of volcanic ash particles creates errors in the detection and modeling of volcanic ash clouds and in quantification of their potential impacts. In this study, we provide a data set that describes the physicochemical and optical properties of a representative selection of volcanic ash samples from nine different volcanic eruptions covering a wide range of silica contents (50–80 wt % SiO2). We measured and calculated parameters describing the physical (size distribution, complex shape, and dense-rock equivalent mass density), chemical (bulk and surface composition), and optical (complex refractive index from ultraviolet to near-infrared wavelengths ...


Reference Data Set Of Volcanic Ash Physicochemical And Optical Properties, A. Vogel, S. Diplas, A. J. Durant, A. S. Azar, M. F. Sunding, William I. Rose, A. Sytchkova, C. Bonadonna, K. Krüger, A. Stohl Sep 2017

Reference Data Set Of Volcanic Ash Physicochemical And Optical Properties, A. Vogel, S. Diplas, A. J. Durant, A. S. Azar, M. F. Sunding, William I. Rose, A. Sytchkova, C. Bonadonna, K. Krüger, A. Stohl

Department of Geological and Mining Engineering and Sciences Publications

Uncertainty in the physicochemical and optical properties of volcanic ash particles creates errors in the detection and modeling of volcanic ash clouds and in quantification of their potential impacts. In this study, we provide a data set that describes the physicochemical and optical properties of a representative selection of volcanic ash samples from nine different volcanic eruptions covering a wide range of silica contents (50–80 wt % SiO2). We measured and calculated parameters describing the physical (size distribution, complex shape, and dense-rock equivalent mass density), chemical (bulk and surface composition), and optical (complex refractive index from ultraviolet to near-infrared ...


Southern African Crustal Evolution And Composition: Constraints From Receiver Function Studies, Shaji K. Nair, Stephen S. Gao, Kelly H. Liu, Paul G. Silver Mar 2017

Southern African Crustal Evolution And Composition: Constraints From Receiver Function Studies, Shaji K. Nair, Stephen S. Gao, Kelly H. Liu, Paul G. Silver

Stephen S. Gao

Stacking of approximately 1500 radial receiver functions recorded at about 80 broadband seismic stations deployed in southern Africa reveals systematic spatial variations in the ratio of crustal P and S wave velocities (Φ), crustal thickness (H), and the amplitude of the converted Moho phases (R). The eastern Zimbabwe and the southern Kaapvaal cratons are characterized by small H (~38 km), small Φ (~1.73), and large R (~0.15) values, suggesting that the relatively undisturbed Archean crust beneath southern Africa is separated from the mantle by a sharp Moho and is felsic in composition. The Limpopo belt, which was created ...


A Practical Anodic And Cathodic Curve Intersection Model To Understand Multiple Corrosion Potentials Of Fe-Based Glassy Alloys In Oh-Contained Solutions, Yingjie Li, Yonggang Wang, Bang An, Hui Xu, Yihua Liu, Laichang Zhang, Houyi Ma, Weimin Wang Jan 2016

A Practical Anodic And Cathodic Curve Intersection Model To Understand Multiple Corrosion Potentials Of Fe-Based Glassy Alloys In Oh-Contained Solutions, Yingjie Li, Yonggang Wang, Bang An, Hui Xu, Yihua Liu, Laichang Zhang, Houyi Ma, Weimin Wang

ECU Publications Post 2013

A practical anodic and cathodic curve intersection model, which consisted of an apparent anodic curve and an imaginary cathodic line, was proposed to explain multiple corrosion potentials occurred in potentiodynamic polarization curves of Fe-based glassy alloys in alkaline solution. The apparent anodic curve was selected from the measured anodic curves. The imaginary cathodic line was obtained by linearly fitting the differences of anodic curves and can be moved evenly or rotated to predict the number and value of corrosion potentials. © 2016 Li et al. This is an open access article distributed under the terms of the Creative Commons Attribution License ...


Thermotropic Phase Boundaries In Classic Ferroelectrics, Tom T. A. Lummen, Yijia Gu, Jianjun Wang Jan 2014

Thermotropic Phase Boundaries In Classic Ferroelectrics, Tom T. A. Lummen, Yijia Gu, Jianjun Wang

Materials Science and Engineering Faculty Research & Creative Works

High-performance piezoelectrics are lead-based solid solutions that exhibit a so-called morphotropic phase boundary, which separates two competing phases as a function of chemical composition; as a consequence, an intermediate low-symmetry phase with a strong piezoelectric effect arises. In search for environmentally sustainable lead-free alternatives that exhibit analogous characteristics, we use a network of competing domains to create similar conditions across thermal inter-ferroelectric transitions in simple, lead-free ferroelectrics such as BaTiO3 and KNbO3. Here we report the experimental observation of thermotropic phase boundaries in these classic ferroelectrics, through direct imaging of low-symmetry intermediate phases that exhibit large enhancements in ...


Flight-Based Chemical Characterization Of Biomass Burning Aerosols Within Two Prescribed Burn Smoke Plumes, K.A. Pratt, Shane Murphy, R. Subramanian, P.J. Demott, G.L. Kok, T. Campos, D.C. Rogers, A.J. Prenni, A.J. Heymsfield, J.H. Seinfeld, K.A. Prather Dec 2011

Flight-Based Chemical Characterization Of Biomass Burning Aerosols Within Two Prescribed Burn Smoke Plumes, K.A. Pratt, Shane Murphy, R. Subramanian, P.J. Demott, G.L. Kok, T. Campos, D.C. Rogers, A.J. Prenni, A.J. Heymsfield, J.H. Seinfeld, K.A. Prather

Atmospheric Science Faculty Publications

Biomass burning represents a major global source of aerosols impacting direct radiative forcing and cloud properties. Thus, the goal of a number of current studies involves developing a better understanding of how the chemical composition and mixing state of biomass burning aerosols evolve during atmospheric aging processes. During the Ice in Clouds Experiment-Layer Clouds (ICE-L) in the fall of 2007, smoke plumes from two small Wyoming Bureau of Land Management prescribed burns were measured by on-line aerosol instrumentation aboard a C-130 aircraft, providing a detailed chemical characterization of the particles. After ∼2-4 min of aging, submicron smoke particles, produced primarily ...


Modeling Chemical And Aerosol Processes In The Transition From Closed To Open Cells During Vocals-Rex, J. Kazil, H. Wang, G. Feingold, A.D. Clarke, Jefferson Robert Snider, A.R. Brandy Aug 2011

Modeling Chemical And Aerosol Processes In The Transition From Closed To Open Cells During Vocals-Rex, J. Kazil, H. Wang, G. Feingold, A.D. Clarke, Jefferson Robert Snider, A.R. Brandy

Atmospheric Science Faculty Publications

Chemical and aerosol processes in the transition from closed-to open-cell circulation in the remote, cloudy marine boundary layer are explored. It has previously been shown that precipitation can initiate a transition from the closed-to the open-cellular state, but that the boundary layer cannot maintain this open-cell state without a resupply of cloud condensation nuclei (CCN). Potential sources of CCN include wind-driven production of sea salt from the ocean, nucleation from the gas phase, and entrainment from the free troposphere. In order to investigate CCN sources in the marine boundary layer and their role in supplying new particles, we have coupled ...


Ice Initiation By Aerosol Particles: Measured And Predicted Ice Nuclei Concentrations Versus Measured Ice Crystal Concentrations In An Orographic Wave Cloud, T. Eidhammer, P.J. Demott, A.J. Prenni, M.D. Petters, C.H. Twohy, D.C. Rogers, J. Stith, A. Heymsfield, Z. Wang, K.A. Pratt, K.A. Prather, Shane Murphy, J.H. Seinfeld, R. Subramanian, S.M. Kreidenweis Aug 2010

Ice Initiation By Aerosol Particles: Measured And Predicted Ice Nuclei Concentrations Versus Measured Ice Crystal Concentrations In An Orographic Wave Cloud, T. Eidhammer, P.J. Demott, A.J. Prenni, M.D. Petters, C.H. Twohy, D.C. Rogers, J. Stith, A. Heymsfield, Z. Wang, K.A. Pratt, K.A. Prather, Shane Murphy, J.H. Seinfeld, R. Subramanian, S.M. Kreidenweis

Atmospheric Science Faculty Publications

The initiation of ice in an isolated orographic wave cloud was compared with expectations based on ice nucleating aerosol concentrations and with predictions from new ice nucleation parameterizations applied in a cloud parcel model. Measurements of ice crystal number concentrations were found to be in good agreement both with measured number concentrations of ice nuclei feeding the clouds and with ice nuclei number concentrations determined from the residual nuclei of cloud particles collected by a counterflow virtual impactor. Using lognormal distributions fitted to measured aerosol size distributions and measured aerosol chemical compositions, ice nuclei and ice crystal concentrations in the ...


Relationships Of Biomass-Burning Aerosols To Ice In Orographic Wave Clouds, C.H. Twohy, P.J. Demott, K.A. Pratt, R. Subramanian, G.L. Kok, Shane Murphy, T. Lersch, A.J. Heymsfield, Zhien Wang, K.A. Prather, J.H. Seinfeld Aug 2010

Relationships Of Biomass-Burning Aerosols To Ice In Orographic Wave Clouds, C.H. Twohy, P.J. Demott, K.A. Pratt, R. Subramanian, G.L. Kok, Shane Murphy, T. Lersch, A.J. Heymsfield, Zhien Wang, K.A. Prather, J.H. Seinfeld

Atmospheric Science Faculty Publications

Ice concentrations in orographic wave clouds at temperatures between -24 ° and -29 °C were shown to be related to aerosol characteristics in nearby clear air during five research flights over the Rocky Mountains. When clouds with influence from colder temperatures were excluded from the dataset, mean ice nuclei and cloud ice number concentrations were very low, on the order of 1-5 L-1. In this environment, ice number concentrations were found to be significantly correlated with the number concentration of larger particles, those larger than both 0.1- and 0.5-μm diameter. Avariety of complementary techniques was used to measure aerosol ...


Chemical Constituents Of The Different Anatomical Parts Of The Oil Palm (Elaeis Guineensis) For Their Sustainable Utilization, S Saka, Mahendra Varman Munusamy M. Varman, M. Shibata, Y. Tono, H. Miyafuji Nov 2008

Chemical Constituents Of The Different Anatomical Parts Of The Oil Palm (Elaeis Guineensis) For Their Sustainable Utilization, S Saka, Mahendra Varman Munusamy M. Varman, M. Shibata, Y. Tono, H. Miyafuji

Mahendra Varman Munusamy (M. Varman)

As the worldwide production of palm oil (Elaeis guineensis) is increasing, concomitant wastes of unutilized parts of the oil palm are also increasing. Thus, effective utilization of these wastes is expected. In this paper, therefore, the chemical composition of cellulose, hemicellulose, lignin and other minor cell wall components was studied for six different anatomical parts of the oil palm such as trunk, frond, mesocarp, endocarp (shell), kernel cake and empty fruit bunch (EFB). As a result, it was shown that cellulose is in a range between 20-40wt% with hemicellulose being 10-35wt%, whereas lignin in a range between 23-52wt%. More in ...


Chemical Stabilization Of Scrap Metal Yard Contaminated Soil Using Ordinary Portland Cement: Strength And Leachability Aspects, Hilmi Mahmud Feb 2007

Chemical Stabilization Of Scrap Metal Yard Contaminated Soil Using Ordinary Portland Cement: Strength And Leachability Aspects, Hilmi Mahmud

Hilmi Mahmud

In this study, the strength development and lechability aspects of metal-contaminated soil treated with ordinary portland cement (OPC) were investigated. The soil was collected from a scrap metal yard within the outskirts of Kuala Lumpur, Malaysia. Metal composition analysis indicated that the predominant metals present in the soil were iron (42,194 mg/kg), aluminium (8874 mg/kg), zinc (690 mg/kg), lead (428 mg/kg), copper (107 mg/kg) and chromium (52 mg/kg). The contaminated soil was treated with OPC using cement-to-dry soil (C/Sd) ratios of 0.5, 1 and 2. The effectiveness of the treatment was ...


High Performance Steel, Purdue Ect Team Jan 2007

High Performance Steel, Purdue Ect Team

ECT Fact Sheets

High strength steels have been available for years, but their use required more welding control and fabrication processes than conventional strength steels. A new grade of high performance steel, HPS-485W or HPS-70W, developed by a cooperative program between the Federal Highway Administration, the American Iron and Steel Institute, and the Department of the Navy in August 1994; uses a new chemical composition that provides improved welding and toughness properties.


Heating Of Calcium Phosphate Crystals: Morphological Consequences And Biological Implications, W. Bohne, J. A. Pouezat, L. Peru, G. Daculsi Jan 1993

Heating Of Calcium Phosphate Crystals: Morphological Consequences And Biological Implications, W. Bohne, J. A. Pouezat, L. Peru, G. Daculsi

Cells and Materials

Sintering hydroxyapatite (HA) and ß-tricalcium phosphate (ß-TCP) affects the chemical composition, the crystallinity, and the morphological features as demonstrated by means of X-ray diffraction (XRD) , infrared spectroscopy (IR), and scanning electron microscopy (SEM). When heated to 1230°C, 16.7% of HA had decomposed to ß-TCP. SEM investigations showed homogeneous, sharp angular polyhedric blocks of 30 to 50 µm with rare surface pores. On heating at 1230°C, ß-TCP had entirely transformed to a-TCP. During sintering, the size of the powder grains increased and progressive bridging between the grains was observed. At 1230°C, a network within round-shaped polyhedric blocks ...