Chemical Characterization of Bed Material Coatingsby LA-ICP-MS and SEM-EDS

NASA Astrophysics Data System (ADS)

Piispanen, M. H.; Mustonen, A. J.; Tiainen, M. S.; Laitinen, R. S.

Bed material coatings and the consequent agglomeration of bed material are main ash-related problems in FB-boilers. The bed agglomeration is a particular problem when combusting biofuels and waste materials. Whereas SEM-EDS together with automated image processing has proven to be a convenient method to study compositional distribution in coating layers and agglomerates, it is a relatively expensive technique and is not necessarily widely available. In this contribution, we explore the suitability of LA-ICP-MS to provide analogous information of the bed.

Development of clean coal and clean soil technologies using advanced agglomeration technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ignasiak, B.; Pawlak, W.; Szymocha, K.

1990-04-01

The specific objectives of the bituminous coal program were to explore and evaluate the application of advanced agglomeration technology for: (1)desulphurization of bituminous coals to sulphur content acceptable within the current EPA SO{sub 2} emission guidelines; (2) deashing of bituminous coals to ash content of less than 10 percent; and (3)increasing the calorific value of bituminous coals to above 13,000 Btu/lb. (VC)

Steam gasification of a thermally pretreated high lignin corn stover simultaneous saccharification and fermentation digester residue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howe, Daniel T.; Taasevigen, Danny; Garcia-Perez, Manuel

Efficient conversion of all components in lignocellulosic biomass is essential to realizing economic feasibility of biorefineries. However, when utilizing biochemical pathways, lignin cannot be fermented. Furthermore, the high lignin and high ash residue resulting from simultaneous saccharification and fermentation (SSF) reactors is difficult to thermochemically process due to feed line plugging and bed agglomeration. In this study a corn stover SSF digester residue was thermally pretreated at 300°C for 22.5 minutes (min) and then gasified in a bubbling fluidized bed gasifier to study the effect of thermal pretreatment on its processing behavior. Untreated, pelletized SSF residue was gasified at themore » same conditions to establish the baseline processing behavior. Results indicate that the thermal pretreatment process removes a substantial portion of the polar and non-polar extractives, with a resultant increase in the concentration of lignin, cellulose, and ash. Feed line plugging was not observed, although bed agglomeration was occurring at similar rates for both feedstocks, suggesting that overall ash content is the most important factor affecting bed agglomeration. Benzene, phenol, and polyaromatic hydrocarbons in the tar were present at higher concentrations in the treated material, with higher tar loading in the product gas. Total product gas generation is lower for the treated material, although the overall gas composition does not change.« less

Experimental study of acoustic agglomeration and fragmentation on coal-fired ash

NASA Astrophysics Data System (ADS)

Shen, Guoqing; Huang, Xiaoyu; He, Chunlong; Zhang, Shiping; An, Liansuo; Wang, Liang; Chen, Yanqiao; Li, Yongsheng

2018-02-01

As the major part of air pollution, inhalable particles, especially fine particles are doing great harm to human body due to smaller particle size and absorption of hazardous components. However, the removal efficiency of current particles filtering devices is low. Acoustic agglomeration is considered as a very effective pretreatment technique for removing particles. Fine particles collide, agglomerate and grow up in the sound field and the fine particles can be removed by conventional particles devices easily. In this paper, the agglomeration and fragmentation of 3 different kinds of particles with different size distributions are studied experimentally in the sound field. It is found that there exists an optimal frequency at 1200 Hz for different particles. The agglomeration efficiency of inhalable particles increases with SPL increasing for the unimodal particles with particle diameter less than 10 μm. For the bimodal particles, the optimal SPLs are 115 and 120 dB with the agglomeration efficiencies of 25% and 55%. A considerable effectiveness of agglomeration could only be obtained in a narrow SPL range and it decreases significantly over the range for the particles fragmentation.

An investigation of co-combustion municipal sewage sludge with biomass in a 20kW BFB combustor under air-fired and oxygen-enriched condition.

PubMed

Kumar, Rajesh; Singh, Ravi Inder

2017-12-01

The behavior of municipal sewage sludge (MSS) with biomass (Guar stalks (GS), Mustard Husk (MH), Prosopis Juliflora Wood (PJW)) has been investigated in a 20kW bubbling fluidized bed (BFB) combustor under both air-fired (A-F) and oxygen-enriched (O-E) conditions. The work presented is divided into three parts, first part cover the thermogravimetric analysis (TGA), second part cover the experimental investigation of BFB combustor, and third part covers the ash analysis. TGA was performed with a ratio of 50%MSS/50%biomass (GS, MH, PJW) and results show that 50%MSS/50%GS has highest combustion characteristic factor (CCF). The experimental investigation of BFB combustor was performed for two different ratios of MSS/biomass (50%/50% and 25%/75%) and the combustion characteristics of blends were distinctive under both A-F and O-E condition. Despite 50%MSS/50%GS showing the highest combustion performance in TGA analysis, it formed agglomerates during burning in BFB. Due to this formation of large amount of agglomerates, de-fluidization was observed in the combustor bed after 65-75min in A-F conditions. The rate of de-fluidization increased under O-E condition. The de-fluidization problem disappeared when the share of MSS was reduced to 25%, but small amounts of the agglomerate were still present in the bed. With oxygen enhancement, the combustion efficiency of BFB combustor was improved and flue gasses were found within permissible limit. The maximum conceivable combustion efficiency (97.1%) for BFB combustor was accomplished by using 50% MSS/50%PJW under O-E condition. Results show that a ratio of 25%MSS/75%biomass combusted successfully inside the BFB combustor and extensive work is required for efficient utilization of significant share of MSS with biomass. SEM/EDS analyses were performed for agglomerate produced and for the damaged heater to study the surface morphology and compositions. The elemental heterogeneity of fly ash generated during MSS/biomass combustion was analyzed using Microwave Plasma-Atomic Emission Spectroscopy (MP-AES). Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of a Dispersant Agent in Fine Coal Recovery from Washery Tailings by Oil Agglomeration (Preliminary Study)

NASA Astrophysics Data System (ADS)

Yasar, Özüm; Uslu, Tuncay

2017-12-01

Among the fine coal cleaning methods, the oil agglomeration process has important advantages such as high process recovery, more clean product, simple dewatering stage. Several coal agglomeration studies have been undertaken recently and effects of different variables on the process performance have been investigated. However, unlike flotation studies, most of the previous agglomeration studies have not used dispersing agents to minimize slime coating effects of clays. In this study, agglomeration process was applied for recovery of fine coals from coal washery tailings containing remarkable amount of fine coal. Negative effect of fine clays during recovery was tried to be eliminated by using dispersing agent instead of de-sliming. Although ash reductions over 90 % were achieved, performance remained below expectations in terms of combustible matter recovery. However, this study is a preliminary one. It is considered that more satisfied results will be obtained in the next studies by changing the variables such as solid ratio, oil dosage, dispersant type and dosage.

Testing of advanced liquefaction concepts in HTI Run ALC-1: Coal cleaning and recycle solvent treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robbins, G.A.; Winschel, R.A.; Burke, F.P.

In 1991, the Department of Energy initiated the Advanced Liquefaction Concepts Program to promote the development of new and emerging technology that has potential to reduce the cost of producing liquid fuels by direct coal liquefaction. Laboratory research performed by researchers at CAER, CONSOL, Sandia, and LDP Associates in Phase I is being developed further and tested at the bench scale at HTI. HTI Run ALC-1, conducted in the spring of 1996, was the first of four planned tests. In Run ALC-1, feed coal ash reduction (coal cleaning) by oil agglomeration, and recycle solvent quality improvement through dewaxing and hydrotreatmentmore » of the recycle distillate were evaluated. HTI`s bench liquefaction Run ALC-1 consisted of 25 days of operation. Major accomplishments were: 1) oil agglomeration reduced the ash content of Black Thunder Mine coal by 40%, from 5.5% to 3.3%; 2) excellent coal conversion of 98% was obtained with oil agglomerated coal, about 3% higher than the raw Black Thunder Mine coal, increasing the potential product yield by 2-3% on an MAF coal basis; 3) agglomerates were liquefied with no handling problems; 4) fresh catalyst make-up rate was decreased by 30%, with no apparent detrimental operating characteristics, both when agglomerates were fed and when raw coal was fed (with solvent dewaxing and hydrotreating); 5) recycle solvent treatment by dewaxing and hydrotreating was demonstrated, but steady-state operation was not achieved; and 6) there was some success in achieving extinction recycle of the heaviest liquid products. Performance data have not been finalized; they will be available for full evaluation in the new future.« less

100% Pet coke or pet coke blends combustion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swindle, D.L.

1996-12-31

Information is outlined on the combustion of 100 percent petroleum coke or petroleum coke blends. Data are presented on NISCO overviews; fuel (coke) characteristics; delayed coke analysis (1995-96); limestone characteristics/effects; limestone preparation; ash characteristics; vortex finders; agglomerization; and NISCO performance results.

Ash chemistry and sintering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skrifvars, B.J.; Backman, R.; Hupa, M.

1996-10-01

The chemistry of a fuel ash is important to consider when ash behavior in combustion or gasification is studied. Four different types of thermal behavior based bed agglomeration and deposit foliation mechanisms have been proposed to be important, (1) partial melting, (2) viscous flow, (3) chemical reaction sintering, and (4) solid state sintering. In this paper we present data from a broader study in which we have quantified the four mechanisms more in detail. The ashes from 10 different types of fuels have been tested for their sintering tendency by a compression strength sintering test. The ashes were also subjectmore » to quantitative wet chemical analyses and combined differential thermal, thermogravimetric (DT/TG) analyses. These thermal behavior predictions were compared with multi-component multi-phase thermodynamic phase equilibrium calculations and further with full scale combustion experience. The results and their relevance to full scale conversion systems are discussed in the paper.« less

Acoustic agglomeration of fine particles based on a high intensity acoustical resonator

NASA Astrophysics Data System (ADS)

Zhao, Yun; Zeng, Xinwu; Tian, Zhangfu

2015-10-01

Acoustic agglomeration (AA) is considered to be a promising method for reducing the air pollution caused by fine aerosol particles. Removal efficiency and energy consuming are primary parameters and generally have a conflict with each other for the industry applications. It was proved that removal efficiency is increased with sound intensity and optimal frequency is presented for certain polydisperse aerosol. As a result, a high efficiency and low energy cost removal system was constructed using acoustical resonance. High intensity standing wave is generated by a tube system with abrupt section driven by four loudspeakers. Numerical model of the tube system was built base on the finite element method, and the resonance condition and SPL increase were confirmd. Extensive tests were carried out to investigate the acoustic field in the agglomeration chamber. Removal efficiency of fine particles was tested by the comparison of filter paper mass and particle size distribution at different operating conditions including sound pressure level (SPL), and frequency. The experimental study has demonstrated that agglomeration increases with sound pressure level. Sound pressure level in the agglomeration chamber is between 145 dB and 165 dB from 500 Hz to 2 kHz. The resonance frequency can be predicted with the quarter tube theory. Sound pressure level gain of more than 10 dB is gained at resonance frequency. With the help of high intensity sound waves, fine particles are reduced greatly, and the AA effect is enhanced at high SPL condition. The optimal frequency is 1.1kHz for aerosol generated by coal ash. In the resonace tube, higher resonance frequencies are not the integral multiplies of the first one. As a result, Strong nonlinearity is avoided by the dissonant characteristic and shock wave is not found in the testing results. The mechanism and testing system can be used effectively in industrial processes in the future.

Ultrafine particle emissions from modern Gasoline and Diesel vehicles: An electron microscopic perspective.

PubMed

Liati, Anthi; Schreiber, Daniel; Arroyo Rojas Dasilva, Yadira; Dimopoulos Eggenschwiler, Panayotis

2018-08-01

Ultrafine (<100 nm) particles related to traffic are of high environmental and human health concern, as they are supposed to be more toxic than larger particles. In the present study transmission electron microscopy (TEM) is applied to obtain a concrete picture on the nature, morphology and chemical composition of non-volatile ultrafine particles in the exhaust of state-of-the-art, Euro 6b, Gasoline and Diesel vehicles. The particles were collected directly on TEM grids, at the tailpipe, downstream of the after-treatment system, during the entire duration of typical driving cycles on the chassis dynamometer. Based on TEM imaging coupled with Energy Dispersive X-ray (EDX) analysis, numerous ultrafine particles could be identified, imaged and analyzed chemically. Particles <10 nm were rarely detected. The ultrafine particles can be distinguished into the following types: soot, ash-bearing soot and ash. Ash consists of Ca, P, Mg, Zn, Fe, S, and minor Sn compounds. Most elements originate from lubricating oil additives; Sn and at least part of Fe are products of engine wear; minor W ± Si-bearing nearly spherical particles in Diesel exhaust derive from catalytic coating material. Ultrafine ash particles predominate over ultrafine soot or are nearly equal in amount, in contrast to emissions of larger sizes where soot is by far the prevalent particle type. This is probably due to the low ash amount per volume fraction in the total emissions, which does not favor formation of large ash agglomerates, opposite to soot, which is abundant and thus easily forms agglomerates of sizes larger than those of the ultrafine range. No significant differences of ultrafine particle characteristics were identified among the tested Gasoline and Diesel vehicles and driving cycles. The present TEM study gives information also on the imaging and chemical composition of the solid fraction of the unregulated sub-23 nm size category particles. Copyright © 2018 Elsevier Ltd. All rights reserved.

MX Siting Investigation Geotechnical Evaluation Conterminous United States. Volume II. Intermediate Screening.

DTIC Science & Technology

1977-12-21

sections of the CSP ( Thordarson and others, 1967; Figure 8). Interbedded materials consist of agglomerates, air-fall and ash-flow tuffs which are welded to...of Economic Geology, 1977, Land resource map of Texas: Bur. Econ. Geol., Univ. Texas, Austin, Texas. (in press). Thordarson , W., Young, R.A., and

Meat and bone meal as secondary fuel in fluidized bed combustion

DOE Office of Scientific and Technical Information (OSTI.GOV)

L. Fryda; K. Panopoulos; P. Vourliotis

2007-07-01

Meat and Bone Meal (MBM) was co-fired in a laboratory scale fluidized bed combustion (FBC) apparatus with two coals. Several fuel blends were combusted under different conditions to study how primary fuel substitution by MBM affects flue gas emissions as well as fluidized bed (FB) agglomeration tendency. MBM, being a highly volatile fuel, caused significant increase of CO emissions and secondary air should be used in industrial scale applications to conform to regulations. The high N-content of MBM is moderately reflected on the increase of nitrogen oxides emissions which are reduced by MBM derived volatiles. The MBM ash, mainly containingmore » bone material rich in Ca, did not create any noteworthy desulphurization effect. The observed slight decrease in SO{sub 2} emissions is predominantly attributed to the lower sulphur content in the coal/MBM fuel mixtures. The SEM/EDS analysis of bed material samples from the coal/MBM tests revealed the formation of agglomerates of bed material debris and ash with sizes that do not greatly exceed the original bed inventory and thus not problematic. 37 refs., 9 figs., 3 tabs.« less

Chemical composition and physical properties of filter fly ashes from eight grate-fired biomass combustion plants.

PubMed

Lanzerstorfer, Christof

2015-04-01

For the handling, treatment and utilization of fly ash from biomass combustion its chemical composition and physical properties are important. In this study eight filter fly ashes from different grate-fired biomass combustion plants were investigated. In fly ash from straw combustion high concentrations of (K) were found, whereas in the fly ash from wood combustion the concentrations of Ca and Mg were higher. The average concentration of PO4(3-) was similar in both types of fly ashes. In all wood fly ashes some measured heavy metal concentrations were above the limits for utilization. The straw fly ashes were much less contaminated and can be utilized. For wood fly ash most parameters showed little variation, except from one fly ash where the dust pre-separator is in poor condition. The average values were: mass median diameter 4.3±0.8 μm, spread of particle size distribution 19±11, particle density 2620±80 kg/m3 and angle of repose 50°±1°. The density of the straw fly ashes is lower (2260±80 kg/m3) and the spread of the size distribution is higher (72±24). For one straw combustion fly ash the values of the mass median diameter and the angle of repose were similar to the values of wood combustion fly ash, for the other straw fly ash the values differed considerably. While the particle size of this fly ash was much smaller, surprisingly the angle of repose was also lower. This can be attributed to the formation of small agglomerates in this fly ash, which were not disintegrated without a certain stress. Copyright © 2015. Published by Elsevier B.V.

Investigation of the influence of humidity on the ultrasonic agglomeration of submicron particles in diesel exhausts.

PubMed

Riera-Franco de Sarabia, E; Elvira-Segura, L; González-Gómez, I; Rodríguez-Maroto, J J; Muñoz-Bueno, R; Dorronsoro-Areal, J L

2003-06-01

Removing very fine particles in the 0.01-1 micro m range generated in diesel combustion is important for air pollution abatement because of the impact such particles have on the environment. By forming larger particles, acoustic agglomeration of submicron particles is presented as a promising process for enhancing the efficiency of the current filtration systems for particle removal. Nevertheless, some authors have pointed out that acoustic agglomeration is much more efficient for larger particles than for smaller particles. This paper studies the effect of humidity on the acoustic agglomeration of diesel exhausts particles in the nanometer size range at 21 kHz. For the agglomeration tests, the experimental facility basically consists of a pilot scale plant with a diesel engine, an ultrasonic agglomeration chamber a dilution system, a nozzle atomizer, and an aerosol sampling and measuring station. The effect of the ultrasonic treatment, generated by a linear array of four high-power stepped-plate transducers on fumes at flow rates of 900 Nm(3)/h, was a small reduction in the number concentration of particles at the outlet of the chamber. However, the presence of humidity raised the agglomeration rate by decreasing the number particle concentration by up to 56%. A numerical study of the agglomeration process as a linear combination of the orthokinetic and hydrodynamic agglomeration coefficients resulting from mutual radiation pressure also found that acoustic agglomeration was enhanced by humidity. Both results confirm the benefit of using high-power ultrasound together with humidity to enhance the agglomeration of particles much smaller than 1 micro m.

First experimental observations on melting and chemical modification of volcanic ash during lightning interaction.

PubMed

Mueller, S P; Helo, C; Keller, F; Taddeucci, J; Castro, J M

2018-01-23

Electrification in volcanic ash plumes often leads to syn-eruptive lightning discharges. High temperatures in and around lightning plasma channels have the potential to chemically alter, re-melt, and possibly volatilize ash fragments in the eruption cloud. In this study, we experimentally simulate temperature conditions of volcanic lightning in the laboratory, and systematically investigate the effects of rapid melting on the morphology and chemical composition of ash. Samples of different size and composition are ejected towards an artificially generated electrical arc. Post-experiment ash morphologies include fully melted spheres, partially melted particles, agglomerates, and vesiculated particles. High-speed imaging reveals various processes occurring during the short lightning-ash interactions, such as particle melting and rounding, foaming, and explosive particle fragmentation. Chemical analyses of the flash-melted particles reveal considerable bulk loss of Cl, S, P and Na through thermal vaporization. Element distribution patterns suggest convection as a key process of element transport from the interior of the melt droplet to rim where volatiles are lost. Modeling the degree of sodium loss delivers maximum melt temperatures between 3290 and 3490 K. Our results imply that natural lighting strikes may be an important agent of syn-eruptive morphological and chemical processing of volcanic ash.

Photocatalytic removal of Congo red dye using MCM-48/Ni2O3 composite synthesized based on silica gel extracted from rice husk ash; fabrication and application.

PubMed

Shaban, Mohamed; Abukhadra, Mostafa R; Hamd, Ahmed; Amin, Ragab R; Abdel Khalek, Ahmed

2017-12-15

MCM-48 mesoporous silica was successfully synthesized from silica gel extracted from rice husk ash and loaded by nickel oxide (Ni 2 O 3 ). The resulted composite was characterized using X-ray diffraction, scanning electron microscope, and UV-vis spectrophotometer. The role of MCM-48 as catalyst support in enhancing the photocatalytic properties of nickel oxide was evaluated through the photocatalytic degradation of Congo red dye under visible light source. MCM-48 as catalyst support for Ni 2 O 3 shows considerable enhancement in the adsorption capacity by 17% and 29% higher than the adsorption capacity of MCM-48 and Ni 2 O 3 , respectively. Additionally, the photocatalytic degradation percentage increased by about 64% relative to the degradation percentage using Ni 2 O 3 as a single component. The adsorption mechanism of MCM-48/Ni 2 O 3 is chemisorption process of multilayer form. The using of MCM-48 as catalyst support for Ni 2 O 3 enhanced the adsorption capacity and the photocatalytic degradation through increasing the surface area and prevents the nickel oxide particles from agglomeration. This was done through fixing nickel oxide particles throughout the porous structure which providing more exposed active adsorption sites and active photocatalyst sites for the incident photons. Based on the obtained results, supporting of nickel oxide particles onto MCM-48 are promising active centers for the degradation of Congo red dye molecules. Copyright © 2017 Elsevier Ltd. All rights reserved.

Prediction of Agglomeration, Fouling, and Corrosion Tendency of Fuels in CFB Co-Combustion

NASA Astrophysics Data System (ADS)

Barišć, Vesna; Zabetta, Edgardo Coda; Sarkki, Juha

Prediction of agglomeration, fouling, and corrosion tendency of fuels is essential to the design of any CFB boiler. During the years, tools have been successfully developed at Foster Wheeler to help with such predictions for the most commercial fuels. However, changes in fuel market and the ever-growing demand for co-combustion capabilities pose a continuous need for development. This paper presents results from recently upgraded models used at Foster Wheeler to predict agglomeration, fouling, and corrosion tendency of a variety of fuels and mixtures. The models, subject of this paper, are semi-empirical computer tools that combine the theoretical basics of agglomeration/fouling/corrosion phenomena with empirical correlations. Correlations are derived from Foster Wheeler's experience in fluidized beds, including nearly 10,000 fuel samples and over 1,000 tests in about 150 CFB units. In these models, fuels are evaluated based on their classification, their chemical and physical properties by standard analyses (proximate, ultimate, fuel ash composition, etc.;.) alongside with Foster Wheeler own characterization methods. Mixtures are then evaluated taking into account the component fuels. This paper presents the predictive capabilities of the agglomeration/fouling/corrosion probability models for selected fuels and mixtures fired in full-scale. The selected fuels include coals and different types of biomass. The models are capable to predict the behavior of most fuels and mixtures, but also offer possibilities for further improvements.

Agglomerating combustor-gasifier method and apparatus for coal gasification

DOEpatents

Chen, Joseph L. P.; Archer, David H.

1976-09-21

A method and apparatus for gasifying coal wherein the gasification takes place in a spout fluid bed at a pressure of about 10 to 30 atmospheres and a temperature of about 1800.degree. to 2200.degree.F and wherein the configuration of the apparatus and the manner of introduction of gases for combustion and fluidization is such that agglomerated ash can be withdrawn from the bottom of the apparatus and gas containing very low dust loading is produced. The gasification reaction is self-sustaining through the burning of a stoichiometric amount of coal with air in the lower part of the apparatus to form the spout within the fluid bed. The method and apparatus are particularly suitable for gasifying coarse coal particles.

Microbial effects on colloidal agglomeration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hersman, L.

1995-11-01

Colloidal particles are known to enhance the transport of radioactive metals through soil and rock systems. This study was performed to determine if a soil microorganism, isolated from the surface samples collected at Yucca Mountain, NV, could affect the colloidal properties of day particles. The agglomeration of a Wyoming bentonite clay in a sterile uninoculated microbial growth medium was compared to the agglomeration in the medium inoculated with a Pseudomonas sp. In a second experiment, microorganisms were cultured in the succinate medium for 50 h and removed by centrifugation. The agglomeration of the clay in this spent was compared tomore » sterile uninoculated medium. In both experiments, the agglomeration of the clay was greater than that of the sterile, uninoculated control. Based on these results, which indicate that this microorganism enhanced the agglomeration of the bentonite clay, it is possible to say that in the presence of microorganisms colloidal movement through a rock matrix could be reduced because of an overall increase in the size of colloidal particle agglomerates. 32 refs.« less

Hydrophobic agglomeration of apatite fines induced by sodium oleate in aqueous solutions

NASA Astrophysics Data System (ADS)

Yang, Bingqiao; Huang, Pengliang; Song, Shaoxian; Luo, Huihua; Zhang, Yi

2018-06-01

In this work, the hydrophobic agglomeration of apatite fines induced by sodium oleate in aqueous solutions has been investigated through the measurement of agglomeration degree and fractal dimension. The results showed that the agglomeration degree of apatite fines and agglomerates morphology was strongly depended on sodium oleate concentration, pH, stirring speed and time. Better agglomeration degree and more regular agglomerates were achieved at sodium oleate concentration of 5 × 10-5 mol/L under neutral condition. The critical stirring speed for agglomerates rupture was 1000 rev/min, above which, prolonged stirring time would cause breakage and restructure of the agglomerates after a certain stirring time, resulting in lower agglomeration degree and more regular agglomerates. The agglomeration degree of apatite fines could be greatly enhanced with the addition of emulsified kerosene, but only if the apatite surface was hydrophobic enough.

Separation of particulate from flue gas of fossil fuel combustion and gasification

DOEpatents

Yang, W.C.; Newby, R.A.; Lippert, T.E.

1997-08-05

The gas from combustion or gasification of fossil fuel contains fly ash and other particulates. The fly ash is separated from the gas in a plurality of standleg moving granular-bed filter modules. Each module includes a dipleg through which the bed media flows into the standleg. The bed media forms a first filter bed having an upper mass having a first frusto-conical surface in a frusto-conical member at the entrance to the standleg and a lower mass having a second frusto-conical surface of substantially greater area than the first surface after it passes through the standleg. A second filter media bed may be formed above the first filter media bed. The gas is fed tangentially into the module above the first surface. The fly ash is captured on the first frusto-conical surface and within the bed mass. The processed gas flows out through the second frusto-conical surface and then through the second filter bed, if present. The bed media is cleaned of the captured fly ash and recirculated to the moving granular bed filter. Alternatively, the bed media may be composed of the ash from the combustion which is pelletized to form agglomerates. The ash flows through the bed only once; it is not recycled. 11 figs.

Detailed characterization of particulate matter emitted by lean-burn gasoline direct injection engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zelenyuk, Alla; Wilson, Jacqueline; Imre, Dan

This study presents detailed characterization of the chemical and physical properties of PM emitted by a 2.0L BMW lean-burn turbocharged GDI engine operated under a number of combustion strategies that include lean homogeneous, lean stratified, stoichiometric, and fuel rich conditions. We characterized PM number concentrations, size distributions, and the size, mass, compositions, and effective density of fractal and compact individual exhaust particles. For the fractal particles, these measurements yielded fractal dimension, average diameter of primary spherules, and number of spherules, void fraction, and dynamic shape factors as function of particle size. Overall, the PM properties were shown to vary significantlymore » with engine operation condition. Lean stratified operation yielded the most diesel-like size distribution and the largest PM number and mass concentrations, with nearly all particles being fractal agglomerates composed of elemental carbon with small amounts of ash and organics. In contrast, stoichiometric operation yielded a larger fraction of ash particles, especially at low speed and low load. Three distinct forms of ash particles were observed, with their fractions strongly dependent on engine operating conditions: sub-50 nm ash particles, abundant at low speed and low load, ash-containing fractal particles, and large compact ash particles that significantly contribute to PM mass loadings« less

The relationship between mineral contents, particle matter and bottom ash distribution during pellet combustion: molar balance and chemometric analysis.

PubMed

Jeguirim, Mejdi; Kraiem, Nesrine; Lajili, Marzouk; Guizani, Chamseddine; Zorpas, Antonis; Leva, Yann; Michelin, Laure; Josien, Ludovic; Limousy, Lionel

2017-04-01

This paper aims to identify the correlation between the mineral contents in agropellets and particle matter and bottom ash characteristics during combustion in domestic boilers. Four agrifood residues with higher mineral contents, namely grape marc (GM), tomato waste (TW), exhausted olive mill solid waste (EOMSW) and olive mill wastewater (OMWW), were selected. Then, seven different pellets were produced from pure residues or their mixture and blending with sawdust. The physico-chemical properties of the produced pellets were analysed using different analytical techniques, and a particular attention was paid to their mineral contents. Combustion tests were performed in 12-kW domestic boiler. The particle matter (PM) emission was characterised through the particle number and mass quantification for different particle size. The bottom ash composition and size distribution were also characterised. Molar balance and chemometric analyses were performed to identify the correlation between the mineral contents and PM and bottom ash characteristics. The performed analyses indicate that K, Na, S and Cl are released partially or completely during combustion tests. In contrast, Ca, Mg, Si, P, Al, Fe and Mn are retained in the bottom ash. The chemometric analyses indicate that, in addition to the operating conditions and the pellet ash contents, K and Si concentrations have a significant effect on the PM emissions as well as on the agglomeration of bottom ash.

Development of advanced fluid-bed agglomeration and cyclonic incineration for simultaneous waste disposal and energy recovery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rehmat, A.; Khinkis, M.

The Institute of Gas Technology (IGT) is currently developing a two-stage fluidized-bed/cyclonic agglomerating incineration system for waste disposal that is based on combining the fluidized-bed agglomeration/incineration and cyclonic combustion techologies. Both technologies have been developed individually at IGT over many years. This combination has resulted in a unique and extremely flexible incinerator for solid, liquid, and gaseous wastes including municipal sludges. The system can operate over a wide range of conditions in the first stage, from low temperature (desorption) to high temperature (agglomeration), including gasification of wastes. In the combined system, solid, liquid, and gaseous organic wastes are incinerated withmore » ease and great efficiency (>99.99% destruction and removal efficiency (DRE)), while solid inorganic contaminants contained within a glassy matrix are rendered benign and suitable for disposal in an ordinary landfill. The heat generated within the incinerator can be recovered using the state-of-the-art boilers. The development of the two-stage incinerator is a culmination of extensive research and development efforts on each stage of the incinerator. The variety of data obtained with solid, liquid, and gaseous wastes for both stages includes agglomeration of ash, incineration and reclamation of used blast grit and foundry sand, partial combustion of carbonaceous fuels, in-situ desulfurization, combustion of low-Btu gases, incineration of industrial wastewater, and incineration of carbon tetrachloride. 5 refs., 7 figs., 12 tabs.« less

Aluminum-fly ash metal matrix composites for automotive parts. [Reports for April 1 to June 30, 1999, and July 1 to September 30, 1999

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weiss, David; Purgert, Robert; Rhudy, Richard

1999-10-15

Some highlights are: (1) During this quarter's field trials, sand mold castings of parts and permanent mold tensile testing bars, K mold bars, and ingots were made from aluminum alloy-fly ash melts. (2) Another objective was met, i.e., to use class ''F'' type precipitator fly ash consisting of particle sizes less than 100 microns. It was possible to pour the composite melt into the sand mold through a filter. (3) Trials were run to determine the required amount of the wetting agent, magnesium, to ensure appropriate mixing of the aluminum alloy and fly ash. The magnesium content required to mixmore » ''F'' fly ash was much lower compared to that required to mix hybrid ''C-F'' fly ash in similar melts. Fly ash particles of less than 100 microns were mixed in aluminum melt. Large scale field trials were undertaken at Eck Industries with the goal of standardizing procedures for producing aluminum-fly ash composite melts and to analyze the structure and properties of the resulting material. Limited testing of tensile properties has been done on pressure die cast parts, and attempts are underway to improve the distribution of fly ash in both sand cast and pressure die cast samples. Eck Industries performed radiographic, heat treatment, and tensile tests on permanent mold cast tensile test bars. After fly ash mixing experiments, the Lanxide high speed-high shear mixer (originally designed for mixing Al-SiC melts) was employed in an attempt to avoid fly ash agglomeration. It led to demixing (instead of deagglomerating) of some fly ash. However, the permanent mold tensile bars poured after high shear mixing displayed good distribution of fly ash in castings. A modified impeller design is being considered for high speed-high shear mixing of aluminum-fly ash melts.« less

Carbon-enriched coal fly ash as a precursor of activated carbons for SO2 removal.

PubMed

Izquierdo, M T; Rubio, B

2008-06-30

Carbon-enriched coal fly ash was evaluated in this work as a low-cost adsorbent for SO2 removal from stack gases. The unburned carbon in coal fly ash was concentrated by mechanical sieving and vegetal oil agglomeration. The carbon concentrates were activated with steam at 900 degrees C in order to develop porosity onto the samples. The performance of these samples in the SO2 abatement was tested in the following conditions: 100 degrees C, 1000 ppmv SO2, 5% O2, 6% water vapor. A good SO2 removal capacity was shown by some of the studied samples that can be related to their textural properties. Cycles of SO2 adsorption/regeneration were carried out in order to evaluate the possibility of thermal regeneration and re-use of these carbons. Regeneration of the exhausted carbons was carried out at 400 degrees C of temperature and a flow of 25 ml/min of Ar. After each cycle, the SO2 removal capacity of the sample decreases.

Wet calcining of trona (sodium sesquicarbonate) and bicarbonate in a mixed solvent

NASA Astrophysics Data System (ADS)

Gärtner, R. S.; Witkamp, G. J.

2002-04-01

Trona ore is used in large amounts for the production of soda ash. A key step in this process is the conversion of trona (sodium sesquicarbonate: Na 2CO 3·NaHCO 3·2H 2O) into soda (sodium carbonate anhydrate: Na 2CO 3). Currently, this conversion is done industrially by calcining of the raw ore in rotary calciners at ca. 120°C or higher (Natural Soda Ash—Occurrences, Processing, and Use, Van Nostrand Reinhold, New York, 1991, p. 267). Trona can however be converted at lower temperatures by using a "wet calcining" technique. In this technique, trona is contacted with an organic or mixed organic-aqueous solvent at a conversion temperature that depends on the water activity of the used solvent. In pure ethylene glycol this temperature can be as low as 55°C. The conversion by "wet calcining" occurs very similar to that in the regular dry calcining process via a solid phase conversion. The anhydrate crystals form directly from the solid trona. This produces pseudomorphs (J. Chem. Eng. Data 8(3) (1963) 301), i.e. agglomerates of fine anhydrate crystals (1-10 μm). At high temperatures, dense, finely pored agglomerates are formed, while the outer shape of the agglomerate retains the prism shape of the trona crystal. At low conversion temperatures, loosely packed or even unstable agglomerates are found.

Thermal Stability and Material Balance of Nanomaterials in Waste Incineration

NASA Astrophysics Data System (ADS)

Paur, H.-R.; Baumann, W.; Hauser, M.; Lang, I.; Teuscher, N.; Seifert, H.; Stapf, D.

2017-06-01

Nanostructured materials are widely used to improve the properties of consumer products such as tires, cosmetics, light weight equipment etc. Due to their complex composition these products are hardly recycled and thermal treatment is preferred. In this study we investigated the thermal stability and material balance of nanostructured metal oxides in flames and in an industrial waste incinerator. We studied the size distribution of nanostructured metal oxides (CeO2, TiO2, SiO2) in a flame reactor and in a heated reaction tube. In the premixed ethylene/air flame, nano-structured CeO2 partly evaporates forming a new particle mode. This is probably due to chemical reactions in the flame. In addition sintering of agglomerates takes place in the flame. In the electrically heated reaction tube however only sintering of the agglomerated nanomaterials is observed. Ceria has a low background in waste incinerators and is therefore a suitable tracer for investigating the fate of nanostructured materials. Low concentrations of Ceria were introduced by a two-phase nozzle into the post-combustion zone of a waste incinerator. By the incineration of coal dust in a burning chamber the Ceria nanoparticles are mainly found in the size range of the fly ash (1 - 10 µm) because of agglomeration. With gas as a fuel less agglomeration was observed and the Ceria nanoparticles were in the particle size range below 1 µm.

Hydrothermal carbonization of rice husk for fuel upgrading

NASA Astrophysics Data System (ADS)

Suteerawattananonda, N.; Kongkaew, N.; Patumsawad, S.

2018-01-01

The biomass is popularly used as renewable energy. In Thailand rice is the most consume agricultural products. Agricultural residues from rice husk can be an energy resource. However, alkali and alkali earth materials (AAEMs) in biomass ash are the causes of corrosion and erosion problem in the heat exchanger equipment, while the acidity of ash affects the slagging agglomeration problem. Reduction of alkali and alkali earth materials can minimize the problem. In order to challenge the reduction of alkali and alkali earth materials in biomass ash, hydrothermal carbonization process was selected. Thai rice husk was used as sample to compare the result of treatment. The rice husk was heated under the condition of different temperature ranged from 180°C to 250°C, at operate pressure ranges from 12 bar to 42 bar with residence holding reaction time 1 hour. The results of proximate analysis show that the percentage by mass of fixed carbon are increased 2 times, but volatile matter is decreased by 40% and ash content is decreased by 11% due to the increment of temperature. Meanwhile, the X-Ray fluorescence (XRF) analysis results show the decreasing of alkali and alkali earth materials are reduced.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boxley, Chett J.; Kadota, Rod

This research program performed by Ceramatec may significantly increase the beneficial utilization of fly ash, and improve the overall performance of high quality animal litter products. Ceramatec has developed a novel high surface area material, which is capable of ammonia adsorption. High surface area zeolites when combined with agglomerated fly ash can significantly reduce the use of naturally mined materials (i.e. clay bentonite) for animal litter manufacture. This not only preserves natural resources and the natural environment, but it also will reduce CO 2 emissions, via the reduced need for heavy mining equipment. This novel animal litter is made withmore » over 85% of recycled materials, thus preventing their disposition to landfills. The novel litter material is similar to traditional clay-like litters, and it is clumpable and has superior odor control properties.« less

Study on surface morphology and physicochemical properties of raw and activated South African coal and coal fly ash

NASA Astrophysics Data System (ADS)

Mishra, S. B.; Langwenya, S. P.; Mamba, B. B.; Balakrishnan, M.

South African coal and coal fly ash were selected as the raw materials to be used for study of their morphology and physicochemical properties and their respective activated carbons for adsorption applications. Coal and fly ash were individually steam activated at a temperature range of 550-1000 °C for 1 h in a muffle furnace using cylindrical stainless steel containers. Scanning electron micrographs revealed a change in surface morphology with more mineral matter available on the surface of the coal particles due to increased devolatilization. However, in the case of fly ash, the macerals coalesced to form agglomerates and the presence of unburnt carbon constituted pores of diameter between 50 and 100 nm. The BET surface area of coal improved significantly from 5.31 to 52.12 m 2/g whereas in case of fly ash the surface area of the raw sample which was originally 0.59 m 2/g and upon activation increased only up to 2.04 m 2/g. The chemical composition of the fly ash confirmed that silica was the major component which was approximately 60% by weight fraction. The impact of this study was to highlight the importance of using raw materials such as coal and a waste product, in the form of coal ash, in order to produce affordable activated carbon that can be used in drinking water treatment. This would therefore ensure that the quality of water supplied to communities for drinking is not contaminated especially by toxic organic compounds.

Combustion of Biosolids in a Bubbling Fluidized Bed, Part 1: Main Ash-Forming Elements and Ash Distribution with a Focus on Phosphorus.

PubMed

Skoglund, Nils; Grimm, Alejandro; Ohman, Marcus; Boström, Dan

2014-02-20

This is the first in a series of three papers describing combustion of biosolids in a 5-kW bubbling fluidized bed, the ash chemistry, and possible application of the ash produced as a fertilizing agent. This part of the study aims to clarify whether the distribution of main ash forming elements from biosolids can be changed by modifying the fuel matrix, the crystalline compounds of which can be identified in the raw materials and what role the total composition may play for which compounds are formed during combustion. The biosolids were subjected to low-temperature ashing to investigate which crystalline compounds that were present in the raw materials. Combustion experiments of two different types of biosolids were conducted in a 5-kW benchscale bubbling fluidized bed at two different bed temperatures and with two different additives. The additives were chosen to investigate whether the addition of alkali (K 2 CO 3 ) and alkaline-earth metal (CaCO 3 ) would affect the speciation of phosphorus, so the molar ratios targeted in modified fuels were P:K = 1:1 and P:K:Ca = 1:1:1, respectively. After combustion the ash fractions were collected, the ash distribution was determined and the ash fractions were analyzed with regards to elemental composition (ICP-AES and SEM-EDS) and part of the bed ash was also analyzed qualitatively using XRD. There was no evidence of zeolites in the unmodified fuels, based on low-temperature ashing. During combustion, the biosolid pellets formed large bed ash particles, ash pellets, which contained most of the total ash content (54%-95% (w/w)). This ash fraction contained most of the phosphorus found in the ash and the only phosphate that was identified was a whitlockite, Ca 9 (K,Mg,Fe)(PO 4 ) 7 , for all fuels and fuel mixtures. With the addition of potassium, cristobalite (SiO 2 ) could no longer be identified via X-ray diffraction (XRD) in the bed ash particles and leucite (KAlSi 2 O 6 ) was formed. Most of the alkaline-earth metals calcium and magnesium were also found in the bed ash. Both the formation of aluminum-containing alkali silicates and inclusion of calcium and magnesium in bed ash could assist in preventing bed agglomeration during co-combustion of biosolids with other renewable fuels in a full-scale bubbling fluidized bed.

Combustion of Biosolids in a Bubbling Fluidized Bed, Part 1: Main Ash-Forming Elements and Ash Distribution with a Focus on Phosphorus

PubMed Central

2014-01-01

This is the first in a series of three papers describing combustion of biosolids in a 5-kW bubbling fluidized bed, the ash chemistry, and possible application of the ash produced as a fertilizing agent. This part of the study aims to clarify whether the distribution of main ash forming elements from biosolids can be changed by modifying the fuel matrix, the crystalline compounds of which can be identified in the raw materials and what role the total composition may play for which compounds are formed during combustion. The biosolids were subjected to low-temperature ashing to investigate which crystalline compounds that were present in the raw materials. Combustion experiments of two different types of biosolids were conducted in a 5-kW benchscale bubbling fluidized bed at two different bed temperatures and with two different additives. The additives were chosen to investigate whether the addition of alkali (K2CO3) and alkaline-earth metal (CaCO3) would affect the speciation of phosphorus, so the molar ratios targeted in modified fuels were P:K = 1:1 and P:K:Ca = 1:1:1, respectively. After combustion the ash fractions were collected, the ash distribution was determined and the ash fractions were analyzed with regards to elemental composition (ICP-AES and SEM-EDS) and part of the bed ash was also analyzed qualitatively using XRD. There was no evidence of zeolites in the unmodified fuels, based on low-temperature ashing. During combustion, the biosolid pellets formed large bed ash particles, ash pellets, which contained most of the total ash content (54%–95% (w/w)). This ash fraction contained most of the phosphorus found in the ash and the only phosphate that was identified was a whitlockite, Ca9(K,Mg,Fe)(PO4)7, for all fuels and fuel mixtures. With the addition of potassium, cristobalite (SiO2) could no longer be identified via X-ray diffraction (XRD) in the bed ash particles and leucite (KAlSi2O6) was formed. Most of the alkaline-earth metals calcium and magnesium were also found in the bed ash. Both the formation of aluminum-containing alkali silicates and inclusion of calcium and magnesium in bed ash could assist in preventing bed agglomeration during co-combustion of biosolids with other renewable fuels in a full-scale bubbling fluidized bed. PMID:24678140

Consolidation of Hierarchy-Structured Nanopowder Agglomerates and Its Application to Net-Shaping Nanopowder Materials

PubMed Central

Lee, Jai-Sung; Choi, Joon-Phil; Lee, Geon-Yong

2013-01-01

This paper provides an overview on our recent investigations on the consolidation of hierarchy-structured nanopowder agglomerates and related applications to net-shaping nanopowder materials. Understanding the nanopowder agglomerate sintering (NAS) process is essential to processing of net-shaped nanopowder materials and components with small and complex shape. The key concept of the NAS process is to enhance material transport through controlling the powder interface volume of nanopowder agglomerates. Based upon this concept, we have suggested a new idea of full density processing for fabricating micro-powder injection molded part using metal nanopowder agglomerates produced by hydrogen reduction of metal oxide powders. Studies on the full density sintering of die compacted- and powder injection molded iron base nano-agglomerate powders are introduced and discussed in terms of densification process and microstructure. PMID:28788317

The Effect of Silane Addition on Chitosan-Fly Ash/CTAB as Electrolyte Membrane

NASA Astrophysics Data System (ADS)

Kusumastuti, E.; Isnaeni, D.; Sulistyaningsih, T.; Mahatmanti, F. W.; Jumaeri; Atmaja, L.; Widiastuti, N.

2017-02-01

Electrolyte membrane is an important component in fuel cell system, because it may influence fuel cell performance. Many efforts have been done to produce electrolyte membrane to replace comercial membrane. In this research, electrolyte membrane is composed of chitosan as an organic matrix and fly ash modified with CTAB and silane as inorganic filler. Fly ash is modified using silane as coupling agent to improve interfacial morphology between organic matrix and inorganic filler. This research aims to determine the best membrane performance based on its characteristics such as water uptake, mechanical properties, proton conductivity, and methanol permeability. The steps that have been done include silica preparation from fly ash, modification of silica surface with CTAB, silica coupling process with silane, synthesis of membranes with inversion phase method, and membrane characterization. The result shows that membrane C-FA/CTAB-Silane 10% (w/w) has the best performance with proton conductivity 8.00 x 10-4 S.cm-1, methanol permeability 3.37 x 10-7 cm.s-1, and selectivity 2.12 x 103 S.s.cm-3. The result of FTIR analysis on membrane C-FA/CTAB-Silane 10% shows that there is only physical interaction occured between chitosan, fly ash and silane, because there is no peak differences significantly at wave number 1000-1250 cm-1, while morphology analysis on membrane with Scanning Electron Microscopy (SEM) shows good dispersion and there is no agglomeration on chitosan matrix.

Characteristics of coking coal burnout

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakamura, M.; Bailey, J.G.

An attempt was made to clarify the characteristics of coking coal burnout by the morphological analysis of char and fly ash samples. Laboratory-scale combustion testing, simulating an ignition process, was carried out for three kinds of coal (two coking coals and one non-coking coal for reference), and sampled chars were analyzed for size, shape and type by image analysis. The full combustion process was examined in industrial-scale combustion testing for the same kinds of coal. Char sampled at the burner outlet and fly ash at the furnace exit were also analyzed. The difference between the char type, swelling properties, agglomeration,more » anisotropy and carbon burnout were compared at laboratory scale and at industrial scale. As a result, it was found that coking coals produced chars with relatively thicker walls, which mainly impeded char burnout, especially for low volatile coals.« less

Thermal and mechanical behaviour of sub micron sized fly ash reinforced polyester resin composite

NASA Astrophysics Data System (ADS)

Nantha Kumar, P.; Rajadurai, A.; Muthuramalingam, T.

2018-04-01

The utilization of particles reinforced resin matrix composites is being increased owing to its lower density and high strength to weight ratio. In the present study, an attempt has been made to synthesize fly ash particles reinforced polyester resin composite for engine cowling application. The thermal stability and mechanical behaviours such as hardness and flexural strength of the composite with 2, 3 and 4 weight % of reinforcement is studied and analyzed. The thermo gravimetric analysis indicates that the higher addition of reinforcement increases the decomposition temperature due to its refractory nature. It is also observed that the hardness increases with higher filler addition owing to the resistance of FA particles towards penetration. The flexural strength is found to increase up to the addition of 3% of FA particles, whereas the polyester resin composite prepared with 4% FA particles addition is observed to have low flexural strength owing to agglomeration of particles.

A novel silica alumina-based backfill material composed of coal refuse and fly ash.

PubMed

Yao, Yuan; Sun, Henghu

2012-04-30

In this paper, a systematic study was conducted to investigate a novel silica alumina-based backfill material composed of coal refuse and fly ash. The coal refuse and fly ash had different properties under various thermal activation temperatures (20 °C, 150 °C, 350 °C, 550 °C, 750 °C and 950 °C). It is known that a thermal activation temperature ranging from 20 °C to 950 °C significantly increases the flowability and pozzolanic properties of the coal refuse; however, the flowability of fly ash decreases when the activation temperature is higher than 550 °C because of a severe agglomeration phenomenon on its surface. An optimal design for this backfill material was determined to include an activated portion composed of 5% coal refuse at 750 °C and 15% fly ash at 20 °C. This combination yields the best performance with excellent flowability, a high compressive strength and a low bleeding rate. The microanalysis results corresponded well with the performance tests at different activation conditions. In the coal refuse, kaolinite peaks began to decrease because of their transformation into metakaolin at 550 °C. Chlorite peaks disappeared at 750 °C. Muscovite peaks decreased at 750 °C and disappeared at 950 °C. During this process, muscovite 2M(1) gradually dehydroxylated to muscovite HT. Furthermore, this paper examined the environmental acceptance and economic feasibility of this technology and found that this silica alumina-based backfill material composed of coal refuse and fly ash not only meets EPA requirements but also has several advantages in industry feasibility when compared with hydraulic backfill, rock backfill and paste backfill. Published by Elsevier B.V.

Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV) systems.

PubMed

Ng, Bing Feng; Xiong, Jin Wen; Wan, Man Pun

2017-01-01

The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM) indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop) that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV) systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency.

Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV) systems

PubMed Central

Xiong, Jin Wen; Wan, Man Pun

2017-01-01

The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM) indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop) that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV) systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency. PMID:28594862

High thermally stable Ni /Ag(Al) alloy contacts on p-GaN

NASA Astrophysics Data System (ADS)

Chou, C. H.; Lin, C. L.; Chuang, Y. C.; Bor, H. Y.; Liu, C. Y.

2007-01-01

Ag agglomeration was found to occur at Ni /Ag to p-GaN contacts after annealing at 500°C. This Ag agglomeration led to the poor thermal stability showed by the Ni /Ag contacts in relation to the reflectivity and electrical properties. However, after alloying with 10at.% Al by e-gun deposition, the Ni /Ag(Al) p-GaN contacts were found to effectively retard Ag agglomeration thereby greatly enhancing the thermal stability. Based on the x-ray photoelectron spectroscopy analysis, the authors believe that the key for the retardation of Ag agglomeration was the formation of ternary Al-Ni-O layer at p-GaN interface.

High thermally stable Ni/Ag(Al) alloy contacts on p-GaN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chou, C. H.; Lin, C. L.; Chuang, Y. C.

2007-01-08

Ag agglomeration was found to occur at Ni/Ag to p-GaN contacts after annealing at 500 degree sign C. This Ag agglomeration led to the poor thermal stability showed by the Ni/Ag contacts in relation to the reflectivity and electrical properties. However, after alloying with 10 at. % Al by e-gun deposition, the Ni/Ag(Al) p-GaN contacts were found to effectively retard Ag agglomeration thereby greatly enhancing the thermal stability. Based on the x-ray photoelectron spectroscopy analysis, the authors believe that the key for the retardation of Ag agglomeration was the formation of ternary Al-Ni-O layer at p-GaN interface.

Fluidized bed combustion of pelletized biomass and waste-derived fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chirone, R.; Scala, F.; Solimene, R.

2008-10-15

The fluidized bed combustion of three pelletized biogenic fuels (sewage sludge, wood, and straw) has been investigated with a combination of experimental techniques. The fuels have been characterized from the standpoints of patterns and rates of fuel devolatilization and char burnout, extent of attrition and fragmentation, and their relevance to the fuel particle size distribution and the amount and size distribution of primary ash particles. Results highlight differences and similarities among the three fuels tested. The fuels were all characterized by limited primary fragmentation and relatively long devolatilization times, as compared with the time scale of particle dispersion away frommore » the fuel feeding ports in practical FBC. Both features are favorable to effective lateral distribution of volatile matter across the combustor cross section. The three fuels exhibited distinctively different char conversion patterns. The high-ash pelletized sludge burned according to the shrinking core conversion pattern with negligible occurrence of secondary fragmentation. The low-ash pelletized wood burned according to the shrinking particle conversion pattern with extensive occurrence of secondary fragmentation. The medium-ash pelletized straw yielded char particles with a hollow structure, resembling big cenospheres, characterized by a coherent inorganic outer layer strong enough to prevent particle fragmentation. Inert bed particles were permanently attached to the hollow pellets as they were incorporated into ash melts. Carbon elutriation rates were very small for all the fuels tested. For pelletized sludge and straw, this was mostly due to the shielding effect of the coherent ash skeleton. For the wood pellet, carbon attrition was extensive, but was largely counterbalanced by effective afterburning due to the large intrinsic reactivity of attrited char fines. The impact of carbon attrition on combustion efficiency was negligible for all the fuels tested. The size distribution of primary ash particles liberated upon complete carbon burnoff largely reflected the combustion pattern of each fuel. Primary ash particles of size nearly equal to that of the parent fuel were generated upon complete burnoff of the pelletized sludge. Nonetheless, secondary attrition of primary ash from pelletized sludge is large, to the point where generation of fine ash would be extensive over the typical residence time of bed ash in fluidized bed combustors. Very few and relatively fine primary ash particles were released after complete burnoff of wood pellets. Primary ash particles remaining after complete burnoff of pelletized straw had sizes and shapes that were largely controlled by the occurrence of ash agglomeration phenomena. (author)« less

Characterisation of the de-agglomeration effects of bovine serum albumin on nanoparticles in aqueous suspension.

PubMed

Tantra, Ratna; Tompkins, Jordan; Quincey, Paul

2010-01-01

This paper describes the use of nanoparticle characterisation tools to evaluate the interaction between bovine serum albumin (BSA) and dispersed nanoparticles in aqueous media. Dynamic light scattering, zeta-potential measurements and scanning electron microscopy were used to probe the state of zinc oxide (ZnO) and titanium dioxide (TiO(2)) nanoparticles in the presence of various concentrations of BSA, throughout a three-day period. BSA was shown to adhere to ZnO but not to TiO(2). The adsorption of BSA led to subsequent de-agglomeration of the sub-micron ZnO clusters into smaller fragments, even breaking them up into individual isolated nanoparticles. We propose that certain factors, such as adsorption kinetics of BSA on to the surface of ZnO, as well as the initial agglomerated state of the ZnO, prior to BSA addition, are responsible for promoting the de-agglomeration process. Hence, in the case of TiO(2) we see no de-agglomeration because: (a) the nanoparticles are more highly agglomerated to begin with and (b) BSA does not adsorb effectively on the surface of the nanoparticles. The zeta-potential results show that, for either ZnO or TiO(2), the presence of BSA resulted in enhanced stability. In the case of ZnO, the enhanced stability is limited to BSA concentrations below 0.5 wt.%. Steric and electrostatic repulsion are thought to be responsible for improved stability of the dispersion.

Sustainability of an in situ aided phytostabilisation on highly contaminated soils using fly ashes: Effects on the vertical distribution of physicochemical parameters and trace elements.

PubMed

Bidar, Géraldine; Waterlot, Christophe; Verdin, Anthony; Proix, Nicolas; Courcot, Dominique; Détriché, Sébastien; Fourrier, Hervé; Richard, Antoine; Douay, Francis

2016-04-15

Aided phytostabilisation using trees and fly ashes is a promising technique which has shown its effectiveness in the management of highly metal-contaminated soils. However, this success is generally established based on topsoil physicochemical analysis and short-term experiments. This paper focuses on the long-term effects of the afforestation and two fly ashes (silico-aluminous and sulfo-calcic called FA1 and FA2, respectively) by assessing the integrity of fly ashes 10 years after their incorporation into the soil as well as the vertical distribution of the physicochemical parameters and trace elements (TEs) in the amended soils (F1 and F2) in comparison with a non-amended soil (R). Ten years after the soil treatment, the particle size distribution analysis between fly ashes and their corresponding masses (fly ash + soil particles) showed a loss or an agglomeration of finer particles. This evolution matches with the appearance of gypsum (CaSO4 2H2O) in FA2m instead of anhydrite (CaSO4), which is the major compound of FA2. This finding corresponds well with the dissolution and the lixiviation of Ca, S and P included in FA2 along the F2 soil profile, generating an accumulation of these elements at 30 cm depth. However, no variation of TE contamination was found between 0 and 25 cm depth in F2 soil except for Cd. Conversely, Cd, Pb, Zn and Hg enrichment was observed at 25 cm depth in the F1 soil, whereas no enrichment was observed for As. The fly ashes studied, and notably FA2, were able to reduce Cd, Pb and Zn availability in soil and this capacity persists over the time despite their structural and chemical changes. Copyright © 2016 Elsevier Ltd. All rights reserved.

A prediction model for the effective thermal conductivity of nanofluids considering agglomeration and the radial distribution function of nanoparticles

NASA Astrophysics Data System (ADS)

Zheng, Z. M.; Wang, B.

2018-06-01

Conventional heat transfer fluids usually have low thermal conductivity, limiting their efficiency in many applications. Many experiments have shown that adding nanosize solid particles to conventional fluids can greatly enhance their thermal conductivity. To explain this anomalous phenomenon, many theoretical investigations have been conducted in recent years. Some of this research has indicated that the particle agglomeration effect that commonly occurs in nanofluids should play an important role in such enhancement of the thermal conductivity, while some have shown that the enhancement of the effective thermal conductivity might be accounted for by the structure of nanofluids, which can be described using the radial distribution function of particles. However, theoretical predictions from these studies are not in very good agreement with experimental results. This paper proposes a prediction model for the effective thermal conductivity of nanofluids, considering both the agglomeration effect and the radial distribution function of nanoparticles. The resulting theoretical predictions for several sets of nanofluids are highly consistent with experimental data.

Nifedipine Nanoparticle Agglomeration as a Dry Powder Aerosol Formulation Strategy

PubMed Central

Plumley, Carl; Gorman, Eric M.; Munson, Eric J.; Berkland, Cory

2009-01-01

Efficient administration of drugs represents a leading challenge in pulmonary medicine. Dry powder aerosols are of great interest compared to traditional aerosolized liquid formulations in that they may offer improved stability, ease of administration, and simple device design. Particles 1–5 µm in size typically facilitate lung deposition. Nanoparticles may be exhaled as a result of their small size; however, they are desired to enhance the dissolution rate of poorly soluble drugs. Nanoparticles of the hypertension drug nifedipine were co-precipitated with stearic acid to form a colloid exhibiting negative surface charge. Nifedipine nanoparticle colloids were destabilized by using sodium chloride to disrupt the electrostatic repulsion between particles as a means to achieve the agglomerated nanoparticles of a controlled size. The aerodynamic performance of agglomerated nanoparticles was determined by cascade impaction. The powders were found to be well suited for pulmonary delivery. In addition, nanoparticle agglomerates revealed enhanced dissolution of the drug species suggesting the value of this formulation approach for poorly water soluble pulmonary medicines. Ultimately, nifedipine powders are envisioned as an approach to treat pulmonary hypertension. PMID:19015016

Deashing macroalgae biomass by pulsed electric field treatment.

PubMed

Robin, Arthur; Sack, Martin; Israel, Alvaro; Frey, Wolfgang; Müller, Georg; Golberg, Alexander

2018-05-01

Among all biomass constituents, the ashes are major hurdles for biomass processing. Ashes currently have low market value and can make a non-negligible fraction of the biomass dry weight significantly impacting its further processing by degrading equipment, lowering process yield, inhibiting reactions and decreasing products qualities. However, most of the current treatments for deashing biomass are of poor efficiency or industrial relevance. This work is the first report on the use of Pulsed Electric Field (PEF) to enhance deashing of biomass from a high ash content green marine macroalga, Ulva sp., using hydraulic pressing. By inducing cell permeabilization of the fresh biomass, PEF was able to enhance the ash extraction from 18.4% (non-treated control) to 37.4% of the total ash content in average, significantly enhancing the extraction of five of the major ash elements (K, Mg, Na, P and S) compared to pressing alone. Copyright © 2018 Elsevier Ltd. All rights reserved.

Advanced direct coal liquefaction concepts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berger, D.J.; Parker, R.J.; Simpson, P.L.

During the first quarter of FY 1993, the Project proceeded close to the Project Plan. The analysis of the feed material has been completed as far as possible. Some unplanned distillation was needed to correct the boiling range of the Black Thunder solvent used during the autoclave tests. Additional distillation will be required if the same solvent is to be used for the bench unit tests. A decision on this is still outstanding. The solvent to be used with Illinois No. 6 coal has not yet been defined. As a result, the procurement of the feed and the feed analysismore » is somewhat behind schedule. Agglomeration tests with Black Thunder coal indicates that small agglomerates can be formed. However, the ash removal is quite low (about 10%), which is not surprising in view of the low ash content of the coal. The first series of autoclave tests with Black Thunder coal was completed as planned. Also, additional runs are in progress as repeats of previous runs or at different operating conditions based on the data obtained so far. The results are promising indicating that almost complete solubilization (close to 90%) of Black Thunder coal can be achieved in a CO/H[sub 2]O environment at our anticipated process conditions. The design of the bench unit has been completed. In contrast to the originally planned modifications, the bench unit is now designed based on a computerized control and data acquisition system. All major items of equipment have been received, and prefabrication of assemblies and control panels is proceeding on schedule. Despite a slight delay in the erection of the structural steel, it is anticipated that the bench unit will be operational at the beginning of April 1993.« less

Advanced direct coal liquefaction concepts. Quarterly report, October 1, 1992--December 31, 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berger, D.J.; Parker, R.J.; Simpson, P.L.

During the first quarter of FY 1993, the Project proceeded close to the Project Plan. The analysis of the feed material has been completed as far as possible. Some unplanned distillation was needed to correct the boiling range of the Black Thunder solvent used during the autoclave tests. Additional distillation will be required if the same solvent is to be used for the bench unit tests. A decision on this is still outstanding. The solvent to be used with Illinois No. 6 coal has not yet been defined. As a result, the procurement of the feed and the feed analysismore » is somewhat behind schedule. Agglomeration tests with Black Thunder coal indicates that small agglomerates can be formed. However, the ash removal is quite low (about 10%), which is not surprising in view of the low ash content of the coal. The first series of autoclave tests with Black Thunder coal was completed as planned. Also, additional runs are in progress as repeats of previous runs or at different operating conditions based on the data obtained so far. The results are promising indicating that almost complete solubilization (close to 90%) of Black Thunder coal can be achieved in a CO/H{sub 2}O environment at our anticipated process conditions. The design of the bench unit has been completed. In contrast to the originally planned modifications, the bench unit is now designed based on a computerized control and data acquisition system. All major items of equipment have been received, and prefabrication of assemblies and control panels is proceeding on schedule. Despite a slight delay in the erection of the structural steel, it is anticipated that the bench unit will be operational at the beginning of April 1993.« less

Centrifugal air-assisted melt agglomeration for fast-release "granulet" design.

PubMed

Wong, Tin Wui; Musa, Nafisah

2012-07-01

Conventional melt pelletization and granulation processes produce round and dense, and irregularly shaped but porous agglomerates respectively. This study aimed to design centrifugal air-assisted melt agglomeration technology for manufacture of spherical and yet porous "granulets" for ease of downstream manufacturing and enhancing drug release. A bladeless agglomerator, which utilized shear-free air stream to mass the powder mixture of lactose filler, polyethylene glycol binder and poorly water-soluble tolbutamide drug into "granulets", was developed. The inclination angle and number of vane, air-impermeable surface area of air guide, processing temperature, binder content and molecular weight were investigated with reference to "granulet" size, shape, texture and drug release properties. Unlike fluid-bed melt agglomeration with vertical processing air flow, the air stream in the present technology moved centrifugally to roll the processing mass into spherical but porous "granulets" with a drug release propensity higher than physical powder mixture, unprocessed drug and dense pellets prepared using high shear mixer. The fast-release attribute of "granulets" was ascribed to porous matrix formed with a high level of polyethylene glycol as solubilizer. The agglomeration and drug release outcomes of centrifugal air-assisted technology are unmet by the existing high shear and fluid-bed melt agglomeration techniques. Copyright © 2012 Elsevier B.V. All rights reserved.

Modeling of Particle Agglomeration in Nanofluids

NASA Astrophysics Data System (ADS)

Kanagala, Hari Krishna

Nanofluids are colloidal dispersions of nano sized particles (<100nm in diameter) in dispersion mediums. They are of great interest in industrial applications as heat transfer fluids owing to their enhanced thermal conductivities. Stability of nanofluids is a major problem hindering their industrial application. Agglomeration and then sedimentation are some reasons, which drastically decrease the shelf life of these nanofluids. Current research addresses the agglomeration effect and how it can affect the shelf life of a nanofluid. The reasons for agglomeration in nanofluids are attributable to the interparticle interactions which are quantified by the various theories. By altering the governing properties like volume fraction, pH and electrolyte concentration different nanofluids with instant agglomeration, slow agglomeration and no agglomeration can be produced. A numerical model is created based on the discretized population balance equations which analyses the particle size distribution at different times. Agglomeration effects have been analyzed for alumina nanoparticles with average particle size of 150nm dispersed in de-ionized water. As the pH was moved towards the isoelectric point of alumina nanofluids, the particle size distribution became broader and moved to bigger sizes rapidly with time. Particle size distributions became broader and moved to bigger sizes more quickly with time with increase in the electrolyte concentration. The two effects together can be used to create different temporal trends in the particle size distributions. Faster agglomeration is attributed to the decrease in the electrostatic double layer repulsion forces which is due to decrease in the induced charge and the double layer thickness around the particle. Bigger particle clusters show lesser agglomeration due to reaching the equilibrium size. The procedures and processes described in this work can be used to generate more stable nanofluids.

Role of Solvents in Improvement of Dissolution Rate of Drugs: Crystal Habit and Crystal Agglomeration

PubMed Central

Maghsoodi, Maryam

2015-01-01

Crystallization is often used for manufacturing drug substances. Advances of crystallization have achieved control over drug identity and purity, but control over the physical form remains poor. This review discusses the influence of solvents used in crystallization process on crystal habit and agglomeration of crystals with potential implication for dissolution. According to literature it has been known that habit modification of crystals by use of proper solvents may enhance the dissolution properties by changing the size, number and the nature of crystal faces exposed to the dissolution medium. Also, the faster dissolution rate of drug from the agglomerates of crystals compared with the single crystals may be related to porous structure of the agglomerates and consequently their better wettability. It is concluded from this review that in-depth understanding of role of the solvents in crystallization process can be applied to engineering of crystal habit or crystal agglomeration, and predictably dissolution improvement in poorly soluble drugs. PMID:25789214

Source identification of individual soot agglomerates in Arctic air by transmission electron microscopy

NASA Astrophysics Data System (ADS)

Weinbruch, S.; Benker, N.; Kandler, K.; Schütze, K.; Kling, K.; Berlinger, B.; Thomassen, Y.; Drotikova, T.; Kallenborn, R.

2018-01-01

Individual soot agglomerates collected at four different locations on the Arctic archipelago Svalbard (Norway) were characterised by transmission electron microscopy and energy-dispersive X-ray microanalysis. For source identification of the ambient soot agglomerates, samples from different local sources (coal burning power plants in Longyearbyen and Barentsburg, diesel and oil burning for power generation in Sveagruva and Ny Ålesund, cruise ship) as well as from other sources which may contribute to Arctic soot concentrations (biomass burning, aircraft emissions, diesel engines) were investigated. Diameter and graphene sheet separation distance of soot primary particles were found to be highly variable within each source and are not suited for source identification. In contrast, concentrations of the minor elements Si, P, K, Ca and Fe showed significant differences which can be used for source attribution. The presence/absence of externally mixed particle groups (fly ashes, tar balls, mercury particles) gives additional hints about the soot sources. Biomass/wood burning, ship emissions and coal burning in Barentsburg can be excluded as major source for ambient soot at Svalbard. The coal power plant in Longyearbyen is most likely a major source of soot in the settlement of Longyearbyen but does not contribute significantly to soot collected at the Global Atmosphere Watch station Zeppelin Mountain near Ny Ålesund. The most probable soot sources at Svalbard are aircraft emissions and diesel exhaust as well as long range transport of coal burning emissions.

Simulation of deterministic energy-balance particle agglomeration in turbulent liquid-solid flows

NASA Astrophysics Data System (ADS)

Njobuenwu, Derrick O.; Fairweather, Michael

2017-08-01

An efficient technique to simulate turbulent particle-laden flow at high mass loadings within the four-way coupled simulation regime is presented. The technique implements large-eddy simulation, discrete particle simulation, a deterministic treatment of inter-particle collisions, and an energy-balanced particle agglomeration model. The algorithm to detect inter-particle collisions is such that the computational costs scale linearly with the number of particles present in the computational domain. On detection of a collision, particle agglomeration is tested based on the pre-collision kinetic energy, restitution coefficient, and van der Waals' interactions. The performance of the technique developed is tested by performing parametric studies on the influence of the restitution coefficient (en = 0.2, 0.4, 0.6, and 0.8), particle size (dp = 60, 120, 200, and 316 μm), Reynolds number (Reτ = 150, 300, and 590), and particle concentration (αp = 5.0 × 10-4, 1.0 × 10-3, and 5.0 × 10-3) on particle-particle interaction events (collision and agglomeration). The results demonstrate that the collision frequency shows a linear dependency on the restitution coefficient, while the agglomeration rate shows an inverse dependence. Collisions among smaller particles are more frequent and efficient in forming agglomerates than those of coarser particles. The particle-particle interaction events show a strong dependency on the shear Reynolds number Reτ, while increasing the particle concentration effectively enhances particle collision and agglomeration whilst having only a minor influence on the agglomeration rate. Overall, the sensitivity of the particle-particle interaction events to the selected simulation parameters is found to influence the population and distribution of the primary particles and agglomerates formed.

Reasons and remedies for the agglomeration of multilayered graphene and carbon nanotubes in polymers

PubMed Central

Atif, Rasheed

2016-01-01

Summary One of the main issues in the production of polymer nanocomposites is the dispersion state of filler as multilayered graphene (MLG) and carbon nanotubes (CNTs) tend to agglomerate due to van der Waals forces. The agglomeration can be avoided by using organic solvents, selecting suitable dispersion and production methods, and functionalizing the fillers. Another proposed method is the use of hybrid fillers as synergistic effects can cause an improvement in the dispersion state of the fillers. In this review article, various aspects of each process that can help avoid filler agglomeration and improve dispersion state are discussed in detail. This review article would be helpful for both current and prospective researchers in the field of MLG- and CNT-based polymer nanocomposites to achieve maximum enhancement in mechanical, thermal, and electrical properties of produced polymer nanocomposites. PMID:27826492

Experimental Evaluation of a Carbon Slurry Droplet Combustion Model

DTIC Science & Technology

1981-12-14

the increased mass and energy transport due to the flow percolating through the open porous structure of the carbon agglomerate. Two separate models...catalysts. Transport-rate enhancement factors were also employed in the carbon-agglomerate reaction analysis to account for the increased mass and energy ...D Effective binary diffusivity Ei Activation energy h Heat transfer coefficient H2 Diatomic hydrogen H20 Water i Enthalpy if Enthalpy of formation

Synthesis of crystalline and amorphous, particle-agglomerated 3-D nanostructures of Al and Si oxides by femtosecond laser and the prediction of these particle sizes

NASA Astrophysics Data System (ADS)

Sivayoganathan, Mugunthan; Tan, Bo; Venkatakrishnan, Krishnan

2012-11-01

We report a single step technique of synthesizing particle-agglomerated, amorphous 3-D nanostructures of Al and Si oxides on powder-fused aluminosilicate ceramic plates and a simple novel method of wafer-foil ablation to fabricate crystalline nanostructures of Al and Si oxides at ambient conditions. We also propose a particle size prediction mechanism to regulate the size of vapor-condensed agglomerated nanoparticles in these structures. Size characterization studies performed on the agglomerated nanoparticles of fabricated 3-D structures showed that the size distributions vary with the fluence-to-threshold ratio. The variation in laser parameters leads to varying plume temperature, pressure, amount of supersaturation, nucleation rate, and the growth rate of particles in the plume. The novel wafer-foil ablation technique could promote the possibilities of fabricating oxide nanostructures with varying Al/Si ratio, and the crystallinity of these structures enhances possible applications. The fabricated nanostructures of Al and Si oxides could have great potentials to be used in the fabrication of low power-consuming complementary metal-oxide-semiconductor circuits and in Mn catalysts to enhance the efficiency of oxidation on ethylbenzene to acetophenone in the super-critical carbon dioxide.

Synthesis of crystalline and amorphous, particle-agglomerated 3-D nanostructures of Al and Si oxides by femtosecond laser and the prediction of these particle sizes.

PubMed

Sivayoganathan, Mugunthan; Tan, Bo; Venkatakrishnan, Krishnan

2012-11-09

We report a single step technique of synthesizing particle-agglomerated, amorphous 3-D nanostructures of Al and Si oxides on powder-fused aluminosilicate ceramic plates and a simple novel method of wafer-foil ablation to fabricate crystalline nanostructures of Al and Si oxides at ambient conditions. We also propose a particle size prediction mechanism to regulate the size of vapor-condensed agglomerated nanoparticles in these structures. Size characterization studies performed on the agglomerated nanoparticles of fabricated 3-D structures showed that the size distributions vary with the fluence-to-threshold ratio. The variation in laser parameters leads to varying plume temperature, pressure, amount of supersaturation, nucleation rate, and the growth rate of particles in the plume. The novel wafer-foil ablation technique could promote the possibilities of fabricating oxide nanostructures with varying Al/Si ratio, and the crystallinity of these structures enhances possible applications. The fabricated nanostructures of Al and Si oxides could have great potentials to be used in the fabrication of low power-consuming complementary metal-oxide-semiconductor circuits and in Mn catalysts to enhance the efficiency of oxidation on ethylbenzene to acetophenone in the super-critical carbon dioxide.

Synthesis of crystalline and amorphous, particle-agglomerated 3-D nanostructures of Al and Si oxides by femtosecond laser and the prediction of these particle sizes

PubMed Central

2012-01-01

We report a single step technique of synthesizing particle-agglomerated, amorphous 3-D nanostructures of Al and Si oxides on powder-fused aluminosilicate ceramic plates and a simple novel method of wafer-foil ablation to fabricate crystalline nanostructures of Al and Si oxides at ambient conditions. We also propose a particle size prediction mechanism to regulate the size of vapor-condensed agglomerated nanoparticles in these structures. Size characterization studies performed on the agglomerated nanoparticles of fabricated 3-D structures showed that the size distributions vary with the fluence-to-threshold ratio. The variation in laser parameters leads to varying plume temperature, pressure, amount of supersaturation, nucleation rate, and the growth rate of particles in the plume. The novel wafer-foil ablation technique could promote the possibilities of fabricating oxide nanostructures with varying Al/Si ratio, and the crystallinity of these structures enhances possible applications. The fabricated nanostructures of Al and Si oxides could have great potentials to be used in the fabrication of low power-consuming complementary metal-oxide-semiconductor circuits and in Mn catalysts to enhance the efficiency of oxidation on ethylbenzene to acetophenone in the super-critical carbon dioxide. PMID:23140103

Consolidation of Partially Stabilized ZrO2 in the Presence of a Noncontacting Electric Field

NASA Astrophysics Data System (ADS)

Majidi, Hasti; van Benthem, Klaus

2015-05-01

Electric field-assisted sintering techniques demonstrate accelerated densification at lower temperatures than the conventional sintering methods. However, it is still debated whether the applied field and/or resulting currents are responsible for the densification enhancement. To distinguish the effects of an applied field from current flow, in situ scanning transmission electron microscopy experiments with soft agglomerates of partially stabilized yttria-doped zirconia particles are carried out. A new microelectromechanical system-based sample support is used to heat particle agglomerates while simultaneously exposing them to an externally applied noncontacting electric field. Under isothermal condition at 900 °C , an electric field strength of 500 V /cm shows a sudden threefold enhancement in the shrinkage of the agglomerates. The applied electrostatic potential lowers the activation energy for point defect formation within the space charge zone and therefore promotes consolidation. Obtaining similar magnitudes of shrinkage in the absence of any electric field requires a higher temperature and longer time.

Colloidal stability of carbonate-coated silver nanoparticles in synthetic and natural freshwater.

PubMed

Piccapietra, Flavio; Sigg, Laura; Behra, Renata

2012-01-17

To gain important information on fate, mobility, and bioavailability of silver nanoparticles (AgNP) in aquatic systems, the influence of pH, ionic strength, and humic substances on the stability of carbonate-coated AgNP (average diameter 29 nm) was systematically investigated in 10 mM carbonate and 10 mM MOPS buffer, and in filtered natural freshwater. Changes in the physicochemical properties of AgNP were measured using nanoparticle tracking analysis, dynamic light scattering, and ultraviolet-visible spectroscopy. According to the pH-dependent carbonate speciation, below pH 4 the negatively charged surface of AgNP became positive and increased agglomeration was observed. Electrolyte concentrations above 2 mM Ca(2+) and 100 mM Na(+) enhanced AgNP agglomeration in the synthetic media. In the considered concentration range of humic substances, no relevant changes in the AgNP agglomeration state were measured. Agglomeration of AgNP exposed in filtered natural freshwater was observed to be primarily controlled by the electrolyte type and concentration. Moreover, agglomerated AgNP were still detected after 7 days of exposure. Consequently, slow sedimentation and high mobility of agglomerated AgNP could be expected under the considered natural conditions. A critical evaluation of the different methods used is presented as well.

Volcanic ash as a driver of enhanced organic carbon burial in the Cretaceous.

PubMed

Lee, Cin-Ty A; Jiang, Hehe; Ronay, Elli; Minisini, Daniel; Stiles, Jackson; Neal, Matthew

2018-03-08

On greater than million year timescales, carbon in the ocean-atmosphere-biosphere system is controlled by geologic inputs of CO 2 through volcanic and metamorphic degassing. High atmospheric CO 2 and warm climates in the Cretaceous have been attributed to enhanced volcanic emissions of CO 2 through more rapid spreading at mid-ocean ridges and, in particular, to a global flare-up in continental arc volcanism. Here, we show that global flare-ups in continental arc magmatism also enhance the global flux of nutrients into the ocean through production of windblown ash. We show that up to 75% of Si, Fe and P is leached from windblown ash during and shortly after deposition, with soluble Si, Fe and P inputs from ash alone in the Cretaceous being higher than the combined input of dust and rivers today. Ash-derived nutrient inputs may have increased the efficiency of biological productivity and organic carbon preservation in the Cretaceous, possibly explaining why the carbon isotopic signature of Cretaceous seawater was high. Variations in volcanic activity, particularly continental arcs, have the potential of profoundly altering carbon cycling at the Earth's surface by increasing inputs of CO 2 and ash-borne nutrients, which together enhance biological productivity and burial of organic carbon, generating an abundance of hydrocarbon source rocks.

Preparation of Cu and Fly Ash Composite by Powder Metallurgy Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chew, P. Y.; Lim, P. S.; Ng, M. C.

2011-03-30

Cu and Fly Ash (FA) mixtures with different weight percentages were prepared. Pellets of the mixture powder were produced with the dimension of 17.7 mm in diameter and 10-15 mm in height. These different composites were compacted at a constant pressure of 280 MPa. One of the selected weight percentages was then compacted to form into pellet and sintered at different temperatures which were at 900, 950 and 1000 deg. C respectively for 2 hours. Density of green pellet was measured before sintered in furnace. After sintering, all the pellets with different temperatures were re-weighed and sintered density were calculated.more » The densification of the green and sintered pellets was required to be measured as one of the parameter in selection of the best material properties. Porosity of the pellet shall not be ignored in order to analyze the close-packed particles stacking in the pellet. SEM micrograph had been captured to observe the presence of pores and agglomeration of particles in the sample produced.« less

Ultrasonication effects on thermal and rheological properties of carbon nanotube suspensions

PubMed Central

2012-01-01

The preparation of nanofluids is very important to their thermophysical properties. Nanofluids with the same nanoparticles and base fluids can behave differently due to different nanofluid preparation methods. The agglomerate sizes in nanofluids can significantly impact the thermal conductivity and viscosity of nanofluids and lead to a different heat transfer performance. Ultrasonication is a common way to break up agglomerates and promote dispersion of nanoparticles into base fluids. However, research reports of sonication effects on nanofluid properties are limited in the open literature. In this work, sonication effects on thermal conductivity and viscosity of carbon nanotubes (0.5 wt%) in an ethylene glycol-based nanofluid are investigated. The corresponding effects on the agglomerate sizes and the carbon nanotube lengths are observed. It is found that with an increased sonication time/energy, the thermal conductivity of the nanofluids increases nonlinearly, with the maximum enhancement of 23% at sonication time of 1,355 min. However, the viscosity of nanofluids increases to the maximum at sonication time of 40 min, then decreases, finally approaching the viscosity of the pure base fluid at a sonication time of 1,355 min. It is also observed that the sonication process not only reduces the agglomerate sizes but also decreases the length of carbon nanotubes. Over the current experimental range, the reduction in agglomerate size is more significant than the reduction of the carbon nanotube length. Hence, the maximum thermal conductivity enhancement and minimum viscosity increase are obtained using a lengthy sonication, which may have implications on application. PMID:22333487

Effect of bacterial inoculants on phytomining of metals from waste incineration bottom ash.

PubMed

Rosenkranz, Theresa; Kidd, Petra; Puschenreiter, Markus

2018-03-01

Waste incineration bottom ash is considered a secondary resource for valuable trace elements (TE), which is currently neglected in most European countries. Phytomining could potentially recover valuable TE from such waste materials but is still at an exploratory stage with many challenges. The use of bioaugmentation to improve plant growth and TE accumulation of metal-tolerant high biomass plants growing on waste incineration bottom ash was evaluated. Bacterial strains that were previously isolated from rhizosphere, roots and contaminated soil were selected according to their plant growth promoting characteristics and tolerance to the bottom ash substrate. Those selected bacterial strains were tested for their beneficial effects on Nicotiana tabacum and Salix smithiana with regards to phytomining. The rhizobacterial strain Rhodococcus erythropolis P30 enhanced the shoot dry weight of N. tabacum by on average 57% compared to the control plants. Several bacterial inoculants enhanced biomass production and the nutritional status of S. smithiana. Moreover, those bacterial strains previously described to enhance biomass production of N. tabacum and members of the Salicaceae on TE-contaminated soils, also enhanced biomass production of these species on bottom ash. However, bacterial inoculants could not enhance trace element accumulation in plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

Solidification and Biotoxicity Assessment of Thermally Treated Municipal Solid Waste Incineration (MSWI) Fly Ash

PubMed Central

Gong, Bing; Deng, Yi; Yang, Yuanyi; Tan, Swee Ngin; Liu, Qianni; Yang, Weizhong

2017-01-01

In the present work, thermal treatment was used to stabilize municipal solid waste incineration (MSWI) fly ash, which was considered hazardous waste. Toxicity characteristic leaching procedure (TCLP) results indicated that, after the thermal process, the leaching concentrations of Pb, Cu, and Zn decreased from 8.08 to 0.16 mg/L, 0.12 to 0.017 mg/L and 0.39 to 0.1 mg/L, respectively, which well met the limits in GB5085.3-2007 and GB16689-2008. Thermal treatment showed a negative effect on the leachability of Cr with concentrations increasing from 0.1 to 1.28 mg/L; nevertheless, it was still under the limitations. XRD analysis suggested that, after thermal treatments, CaO was newly generated. CaO was a main contribution to higher Cr leaching concentrations owing to the formation of Cr (VI)—compounds such as CaCrO4. SEM/EDS tests revealed that particle adhesion, agglomeration, and grain growth happened during the thermal process and thus diminished the leachability of Pb, Cu, and Zn, but these processes had no significant influence on the leaching of Cr. A microbial assay demonstrated that all thermally treated samples yet possessed strong bactericidal activity according to optical density (OD) test results. Among all samples, the OD value of raw fly ash (RFA) was lowest followed by FA700-10, FA900-10, and FA1100-10 in an increasing order, which indicated that the sequence of the biotoxicity for these samples was RFA > FA700-10 > FA900-10 > FA1100-10. This preliminary study indicated that, apart from TCLP criteria, the biotoxicity assessment was indispensable for evaluating the effect of thermal treatment for MSWI fly ash. PMID:28604580

Effect of mixing geopolymer and peat on bearing capacity in Ogan Komering Ilir (OKI) by California bearing ratio (CBR) test

NASA Astrophysics Data System (ADS)

Raharja, Danang S.; Hadiwardoyo, Sigit P.; Rahayu, Wiwik; Zain, Nasuhi

2017-06-01

Geopolymer is binder material that consists of solid material and the activator solution. Geopolymer material has successfully replaced cement in the manufacture of concrete with aluminosilicate bonding system. Geopolymer concrete has properties similar to cement concrete with high compressive strength, low shrinkage value, relatively low creep value, as well as acid-resistant. Based on these, the addition of polymers in peat soils is expected to improve the bearing capacity of peat soils. A study on the influence of geopolymer addition in peat soils was done by comparing before and after the peat soil was mixed with geopolymer using CBR (California Bearing Ratio) test in unsoaked and soaked conditions. 10% mixture content of the peat dry was used, weighted with a variety of curing time 4 hours, 5 days, and 10 days. There were two methods of mixing: first, peat was mixed with fly ash geopolymer activators and mixed solution (waterglass, NaOH, water), and second, peat was mixed with fly ash and mixed geopolymer (waterglass, NaOH, water, fly ash). Changes were observed in specific gravity, dry density, acidity (pH), and the microscopic structure with Scanning Electron Microscope (SEM). Curing time did not significantly affect the CBR value. It even shows a tendency to decline with longer curing time. The first type mixture obtained CBR value of: 5.4% for 4 hours curing, 4.6% for 5 days curing and 3.6% for 10 days curing. The second type mixture obtained CBR value of: 6.1% for 4 hours curing, 5.2% for 5 days curing and 5.2% for 10 days curing. Furthermore, the specific gravity value, dry density, pH near neutral and swelling percentage increased. From both variants, the second type mixture shows better results than the first type mixture. The results of SEM (Scanning Electron Microscopy) show the structure of the peat which became denser with the fly ash particles filling the peat microporous. Also, the reaction of fly ash with geopolymer is indicated by the solid agglomerates that are larger than normal fly ash particle size.

Use of mesophilic and thermophilic bacteria for the improvement of copper extraction from a low-grade ore

NASA Astrophysics Data System (ADS)

Darezereshki, E.; Schaffie, M.; Lotfalian, M.; Seiedbaghery, S. A.; Ranjbar, M.

2011-04-01

Bioleaching was examined for copper extraction from a low grade ore using mesophilic and moderate thermophilic bacteria. Five equal size columns were used for the leaching of the ore. Sulfuric acid solution with a flow rate of 3.12 L·m-2·h-1 and pH 1.5 passed through each column continuously for 90 d. In the first and the second column, bioleaching was performed without agglomeration of the ore and on the agglomerated ore, respectively. 28wt% of the copper was extracted in the first column after 40 d, while this figure was 38wt% in the second column. After 90 d, however, the overall extractions were almost the same for both of them. Bioleaching with mesophilic bacteria was performed in the third column without agglomeration of the ore and in the fourth column on the agglomerated ore. After 40 d, copper extractions in the third and the fourth columns were 62wt% and 70wt%, respectively. Copper extractions were 75wt% for both the columns after 90 d. For the last column, bioleaching was performed with moderate thermophilic bacteria and agglomerated ore. Copper extractions were 80wt% and 85wt% after 40 and 90 d, respectively. It was concluded that crushing and agglomeration of the ore using bacteria could enhance the copper extraction considerably.

Temperature-Switchable Agglomeration of Magnetic Particles Designed for Continuous Separation Processes in Biotechnology.

PubMed

Paulus, Anja S; Heinzler, Raphael; Ooi, Huey Wen; Franzreb, Matthias

2015-07-08

The purpose of this work was the synthesis and characterization of thermally switchable magnetic particles for use in biotechnological applications such as protein purification and enzymatic conversions. Reversible addition-fragmentation chain-transfer polymerization was employed to synthesize poly(N-isopropylacrylamide) brushes via a "graft-from" approach on the surface of magnetic microparticles. The resulting particles were characterized by infrared spectroscopy and thermogravimetric analysis and their temperature-dependent agglomeration behavior was assessed. The influence of several factors on particle agglomeration (pH, temperature, salt type, and particle concentration) was evaluated. The results showed that a low pH value (pH 3-4), a kosmotropic salt (ammonium sulfate), and a high particle concentration (4 g/L) resulted in improved agglomeration at elevated temperature (40 °C). Recycling of particles and reversibility of the temperature-switchable agglomeration were successfully demonstrated for ten heating-cooling cycles. Additionally, enhanced magnetic separation was observed for the modified particles. Ionic monomers were integrated into the polymer chain to create end-group functionalized particles as well as two- and three-block copolymer particles for protein binding. The adsorption of lactoferrin, bovine serum albumin, and lysozyme to these ion exchange particles was evaluated and showed a binding capacity of up to 135 mg/g. The dual-responsive particles combined magnetic and thermoresponsive properties for switchable agglomeration, easy separability, and efficient protein adsorption.

Alternating Field Electronanofluidization

NASA Astrophysics Data System (ADS)

Espin, M. J.; Valverde, J. M.; Quintanilla, M. A. S.; Castellanos, A.

2009-06-01

The use of fluidized beds to remove submicron particles from gases has been investigated since 1949. High efficiency removal was achieved in the 1970's by imposing an electric field on a fluidized bed of semi-insulating granules that were able to collect the charged pollutant entrained in the fluidizing gas. In spite of their extended use nowadays, the collection efficiency of electrofluidized beds (EFB) is still hindered by gas bypassing associated to gas bubbling and the consequent requirement of too high gas flow and pressure drop. In this paper we report on the electromechanical behavior of an EFB of insulating nanoparticles. When fluidized by gas, these nanoparticles form extremely porous light agglomerates of size of the order of hundreds of microns that allow for a highly expanded nonbubbling fluidized state at reduced gas flow. It is found that fluidization uniformity and bed expansion are additionally enhanced by an imposed AC electric field for field oscillation frequencies of several tens of hertzs and field strengths of the order of 1 kV/cm. For oscillation frequencies of the order of hertzs, or smaller, bed expansion is hindered due to electrophoretic deposition of the agglomerates onto the vessel walls, whereas for oscillation frequencies of the order of kilohertzs, or larger, electrophoresis is nullified and bed expansion is not affected. According to a proposed model, the size of nanoparticle agglomerates stems from the balance between shear, which depends on field strength, and van der Waals forces. The optimum field strength for enhancing bed expansion produces an electric force on the agglomerates similar to their weight force, while the oscillation velocity of the agglomerates is similar to the gas velocity.

ELECTROSTATIC ENHANCEMENT OF FABRIC FILTRATION OF FLY ASH AND SPRAY DRYER BY-PRODUCT

EPA Science Inventory

The paper describes small pilot-scale experiments, showing that the pressure drop increase during the fabric filtration of redispersed spray dryer by-product (chiefly calcium salts and fly ash) is significantly reduced by electrostatic enhancement of the filtration. The pressure ...

Lube oil-dependent ash chemistry on soot oxidation reactivity in a gasoline direct-injection engine

DOE PAGES

Choi, Seungmok; Seong, Heeje

2016-09-30

Gasoline particulate filters (GPF) are considered an enabling technology to meet stringent particulate matter (PM) regulations for gasoline direct-injection (GDI) engines, which are known to produce significant PM emissions. While ash loading in filters has been recognized to be detrimental in filter performance by increasing back pressure, increased ash fractions in soot were observed to enhance soot oxidation. In this study, GDI soot samples derived from different gasoline/lube oil blends were evaluated to identify potential promoting factors when formulated lube oils were dosed into gasoline fuel. Ca-derived ash enhanced soot oxidation remarkably, while P- and ZDDP-derived ash deteriorated soot oxidation.more » It is apparent that the promoting effect of lube oil-derived ash is due mainly to the Ca component that is the most abundant among additive components in lube oil. Bulk and surface analyses of these ash compounds indicate that Ca-derived ash would be complex compounds, while the contribution of CaSO 4, which is one of the most abundant ash compounds from diesel engines, is almost negligible. For the validation of the ash promoting impact in filters, the regeneration experiments were compared for a TWC-coated GPF in a GDI engine before and after ash loading was performed. The pressure drop of the ash-loaded GPF decreased noticeably in the initial regeneration stage and it increased gradually, whereas that of no ash-loaded GPF increased gradually without any reduction. So, it is concluded that the ash layer in the GPF assisted soot oxidation in the early regeneration stage when it was in close contact with soot.« less

Lube oil-dependent ash chemistry on soot oxidation reactivity in a gasoline direct-injection engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Seungmok; Seong, Heeje

Gasoline particulate filters (GPF) are considered an enabling technology to meet stringent particulate matter (PM) regulations for gasoline direct-injection (GDI) engines, which are known to produce significant PM emissions. While ash loading in filters has been recognized to be detrimental in filter performance by increasing back pressure, increased ash fractions in soot were observed to enhance soot oxidation. In this study, GDI soot samples derived from different gasoline/lube oil blends were evaluated to identify potential promoting factors when formulated lube oils were dosed into gasoline fuel. Ca-derived ash enhanced soot oxidation remarkably, while P- and ZDDP-derived ash deteriorated soot oxidation.more » It is apparent that the promoting effect of lube oil-derived ash is due mainly to the Ca component that is the most abundant among additive components in lube oil. Bulk and surface analyses of these ash compounds indicate that Ca-derived ash would be complex compounds, while the contribution of CaSO 4, which is one of the most abundant ash compounds from diesel engines, is almost negligible. For the validation of the ash promoting impact in filters, the regeneration experiments were compared for a TWC-coated GPF in a GDI engine before and after ash loading was performed. The pressure drop of the ash-loaded GPF decreased noticeably in the initial regeneration stage and it increased gradually, whereas that of no ash-loaded GPF increased gradually without any reduction. So, it is concluded that the ash layer in the GPF assisted soot oxidation in the early regeneration stage when it was in close contact with soot.« less

Enhancing the engineering properties of expansive soil using bagasse ash

NASA Astrophysics Data System (ADS)

Silmi Surjandari, Niken; Djarwanti, Noegroho; Umri Ukoi, Nafisah

2017-11-01

This paper deals with stabilization of expansive soil on a laboratory experimental basis. The aim of the research was to evaluate the enhancement of the engineering properties of expansive soil using bagasse ash. The soil is treated with bagasse ash by weight (0, 5, 10, 15, and 20%) based on dry mass. The performance of bagasse ash stabilized soil was evaluated using physical and strength performance tests, namely the plasticity index, standard Proctor compaction, and percentage swelling. An X-ray diffraction (XRD) test was conducted to evaluate the clay mineral, whereas an X-ray fluorescence (XRF) was to the chemical composition of bagasse ash. From the results, it was observed that the basic tests carried out proved some soil properties after the addition of bagasse ash. Furthermore, the plasticity index decreased from 53.18 to 47.70%. The maximum dry density of the specimen increased from 1.13 to 1.24 gr/cm3. The percentage swelling decreased from 5.48 to 3.29%. The outcomes of these tests demonstrate that stabilization of expansive soils using bagasse ash can improve the strength.

Recent Advances in the Development and Application of Power Plate Transducers in Dense Gas Extraction and Aerosol Agglomeration Processes

NASA Astrophysics Data System (ADS)

Riera, E.; Cardoni, A.; Gallego-Juárez, J. A.; Acosta, V. M.; Blanco, A.; Rodríguez, G.; Blasco, M.; Herranz, L. E.

Power ultrasound (PU) is an emerging, innovative, energy saving and environmental friendly technology that is generating a great interest in sectors such as food and pharmaceutical industries, green chemistry, environmental pollution, and other processes, where sustainable and energy efficient methods are required to improve and/or produce specific effects. Two typical effects of PU are the enhancement of mass transfer in gases and liquids, and the induction of particle agglomeration in aerosols. These effects are activated by a variety of mechanisms associated to the nonlinear propagation of high amplitude ultrasonic waves such as diffusion, agitation, entrainment, turbulence, etc. During the last years a great effort has been jointly made by the Spanish National Research Council (CSIC) and the company Pusonics towards introducing novel processes into the market based on airborne ultrasonic plate transducers. This technology was specifically developed for the treatment of gas and multiphasic media characterized by low specific acoustic impedance and high acoustic absorption. Different strategies have been developed to mitigate the effects of the nonlinear dynamic behavior of such ultrasonic piezoelectric transducers in order to enhance and stabilize their response at operational power conditions. This work deals with the latter advances in the mitigation of nonlinear problems found in power transducers; besides it describes two applications assisted by ultrasound developed at semi-industrial and laboratory scales and consisting in extraction via dense gases and particle agglomeration. Dense Gas Extraction (DGE) assisted by PU is a new process with a potential to enhance the extraction kinetics with supercritical CO2. Acoustic agglomeration of fine aerosol particles has a great potential for the treatment of air pollution problems generated by particulate materials. Experimental and numerical results in both processes will be shown and discussed.

The role of fly-ash particulate material and oxide catalysts in stone degradation

NASA Astrophysics Data System (ADS)

Hutchinson, A. J.; Johnson, J. B.; Thompson, G. E.; Wood, G. C.; Sage, P. W.; Cooke, M. J.

Studies of fly-ash composition identified the presence of calcium and sulphur, indicating their potential role as sources of calcium sulphate. Residual acidity (particularly for oil fly ash) suggested the possibility of enhanced chemical reaction, and the presence of transition metals, probably as oxides, might accelerate the oxidation of SO 2 to SO 42-. Exposure tests in a laboratory-based rig simulating dry deposition on Portland and Monks Park limestone, either seeded or unseeded with fly-ash particulate material or transition metal oxide catalysts, were carried out using an SO 2-containing environment at 95% r.h. Enhanced sulphation of these seeded limestones due to the above factors was minimal; at high loadings of fly ash, there was even evidence of masking the limestone surface, reducing sulphation. However, pure CaCO 3 powder in the exposure rig showed increases in sulphation when seeded with metal oxide catalysts. Thus the limestones examined contained sufficient inherent catalysts for the oxidation of SO 2 to SO 42- to proceed at such a rate that external catalysts were superfluous. This implies that dissolution rate of SO 2 in moisture films controls the availability of species for reaction with these carbonate-based stones and that fly ash deposited from the atmosphere does not enhance the reaction.

Effects of different surface modification and contents on municipal solid waste incineration fly ash/epoxy composites.

PubMed

Goh, C K; Valavan, S E; Low, T K; Tang, L H

2016-12-01

Incineration fly ash, a waste from municipal solid waste incineration plant can be used to replace conventional filler as reinforcing filler to enhance the mechanical strength of a composite. Surface modification was performed on the incineration fly ash before mixing into the soft polymer matrix so as to improve interfacial bond of the filler and epoxy resin. In this study, detailed characterisation of mechanical, morphological and leaching behaviours of municipal solid waste incineration (MSWI) fly ash infused composite has been carried out. Flexural and tensile test was conducted to determine the effect on mechanical properties of the composite by varying the concentration of incineration fly ash filler added into polymer matrix and surface modification of incineration fly ash filler using silane coupling agent and colloidal mesoporous silica (CMS). The results indicated that composite infused with incineration fly ash filler surface treated with CMS shown improvement on the tensile and flexural strengths. In addition, SEM images showed that surface modification of incineration fly ash with colloidal mesoporous silica enhanced the interfacial bonding with polymer resin which explained the improvement of mechanical strength. Leaching test showed result of toxic metals such as Pb, Zn, Fe, Cu, Cr, Cd and Rb immobilised in the polymer matrix of the composite. Hence, the use of MSWI fly ash as reinforcing filler in the composite appears green and sustainable because this approach is a promising opportunity to substitute valuable raw material with MSWI fly ash. Copyright © 2016 Elsevier Ltd. All rights reserved.

Decreased emergence of emerald ash borer from ash treated with methyl jasmonate is associated with induction of general defense traits and the toxic phenolic compound verbascoside.

PubMed

Whitehill, Justin G A; Rigsby, Chad; Cipollini, Don; Herms, Daniel A; Bonello, Pierluigi

2014-12-01

The emerald ash borer (EAB; Agrilus planipennis Fairmaire) is causing widespread mortality of ash (Fraxinus spp.) in North America. To date, no mechanisms of host resistance have been identified against this pest. Methyl jasmonate was applied to susceptible North American and resistant Asian ash species to determine if it can elicit induced responses in bark that enhance resistance to EAB. In particular, phenolic compounds, lignin, and defense-related proteins were quantified, and compounds associated with resistance were subsequently tested directly against EAB larvae in bioassays with artificial diet. MeJA application decreased adult emergence in susceptible ash species, comparable to levels achieved by insecticide application. Concentration of the phenolic compound verbascoside sharply increased after MeJA application to green and white ash. When incorporated in an artificial diet, verbascoside decreased survival and growth of EAB neonates in a dose-dependent fashion. Lignin and trypsin inhibitors were also induced by MeJA, and analogs of both compounds reduced growth of EAB larvae in artificial diets. We conclude that the application of MeJA prior to EAB attack has the ability to enhance resistance of susceptible ash trees by inducing endogenous plant defenses, and report evidence that induction of verbascoside is a mechanism of resistance to EAB.

Removal of Strontium from Drinking Water by Conventional ...

EPA Pesticide Factsheets

The United States Environmental Protection Agency Contaminant Candidate List 3 lists strontium as a contaminant for potential regulatory consideration in drinking water. There is very little data available on strontium removal from drinking water. As a result, there is an immediate need to perform treatment studies. The objective of this work is to evaluate the effectiveness of conventional and lime-soda ash softening treatments to remove strontium from surface and ground waters. Conventional drinking water treatment with aluminum and iron coagulants were able to achieve 12% and 5.9% strontium removal at best, while lime softening removed as much as 78% from natural strontium-containing ground water. Systematic fundamental experiments showed that strontium removal during the lime-soda ash softening was related to pH, calcium concentration and dissolved inorganic carbon concentration. Final strontium concentration was also directly associated with initial strontium concentration. Precipitated solids showed well-formed crystals or agglomerates of mixed solids, two polymorphs of calcium carbonate (vaterite and calcite), and strontianite, depending on initial water quality conditions. X-ray diffraction analysis suggested that strontium likely replaced calcium inside the crystal lattice and was likely mainly responsible for removal during lime softening. To inform the public.

Post-Plasma SiOx Coatings of Metal and Metal Oxide Nanoparticles for Enhanced Thermal Stability and Tunable Photoactivity Applications

PubMed Central

Post, Patrick; Jidenko, Nicolas; Weber, Alfred P.; Borra, Jean-Pascal

2016-01-01

The plasma-based aerosol process developed for the direct coating of particles in gases with silicon oxide in a continuous chemical vapor deposition (CVD) process is presented. It is shown that non-thermal plasma filaments induced in a dielectric barrier discharge (DBD) at atmospheric pressure trigger post-DBD gas phase reactions. DBD operating conditions are first scanned to produce ozone and dinitrogen pentoxide. In the selected conditions, these plasma species react with gaseous tetraethyl orthosilicate (TEOS) precursor downstream of the DBD. The gaseous intermediates then condense on the surface of nanoparticles and self-reactions lead to homogeneous solid SiOx coatings, with thickness from nanometer to micrometer. This confirms the interest of post-DBD injection of the organo-silicon precursor to achieve stable production of actives species with subsequent controlled thickness of SiOx coatings. SiOx coatings of spherical and agglomerated metal and metal oxide nanoparticles (Pt, CuO, TiO2) are achieved. In the selected DBD operating conditions, the thickness of homogeneous nanometer sized coatings of spherical nanoparticles depends on the reaction duration and on the precursor concentration. For agglomerates, operating conditions can be tuned to cover preferentially the interparticle contact zones between primary particles, shifting the sintering of platinum agglomerates to much higher temperatures than the usual sintering temperature. Potential applications for enhanced thermal stability and tunable photoactivity of coated agglomerates are presented. PMID:28335219

Ambiance-dependent agglomeration and surface-enhanced Raman spectroscopy response of self-assembled silver nanoparticles for plasmonic photovoltaic devices

NASA Astrophysics Data System (ADS)

Gwamuri, Jephias; Venkatesan, Ragavendran; Sadatgol, Mehdi; Mayandi, Jeyanthinath; Guney, Durdu O.; Pearce, Joshua M.

2017-07-01

The agglomeration/dewetting process of thin silver films provides a scalable method of obtaining self-assembled nanoparticles (SANPs) for plasmonics-based thin-film solar photovoltaic (PV) devices. We show the effect of annealing ambiance on silver SANP average size, particle/cluster finite shape, substrate area coverage/particle distribution, and how these physical parameters influence optical properties and surface-enhanced Raman scattering (SERS) responses of SANPs. Statistical analysis performed indicates that generally Ag SANPs processed in the presence of a gas (argon and nitrogen) ambiance tend to have smaller average size particles compared to those processed under vacuum. Optical properties are observed to be highly dependent on particle size, separation distance, and finite shape. The greatest SERS enhancement was observed for the argon-processed samples. There is a correlation between simulation and experimental data that indicate argon-processed AgNPs have a great potential to enhance light coupling when integrated to thin-film PV.

Retention and leaching of nitrite by municipal solid waste incinerator bottom ash under the landfill circumstance.

PubMed

Yao, Jun; Kong, Qingna; Zhu, Huayue; Long, Yuyang; Shen, Dongsheng

2015-01-01

The retention and leaching of nitrite by municipal solid waste incinerator (MSWI) bottom ash could affect its migration in the landfill. In this study, the effect of the dosage of MSWI bottom ash as well as the variation of the landfill environmental parameters including pH, anions and organic matter on the nitrite retention and leaching behavior was investigated by batch experiments. The highest removal percentage (73.0%) of nitrite was observed when the dosage of MSWI bottom ash was 10 g L(-1) in 2 mg L(-1) nitrite solution. Further increase of the dosage would retard the retention, as the nitrite leaching from MSWI bottom ash was enhanced. The optimum retention of nitrite was observed when the pH was 5.0, while the leaching of nitrite showed a consistent reduction with the increase of pH. Besides, the presence of Cl(-), SO4(2)(-) and acetic acid could enhance the leaching of nitrite and mitigate the retention process. However, the retention of nitrite was enhanced by PO4(3)(-), which was probably due to the formation of the apatite, an active material for the adsorption of the nitrite. These results suggested that MSWI bottom ash could affect the migration of nitrite in the landfill, which was related to the variation of the landfill circumstance. Copyright © 2014 Elsevier Ltd. All rights reserved.

Morphological evolution of various fungal species in the presence and absence of aluminum oxide microparticles: Comparative and quantitative insights into microparticle-enhanced cultivation (MPEC).

PubMed

Kowalska, Anna; Boruta, Tomasz; Bizukojć, Marcin

2018-03-05

The application of microparticle-enhanced cultivation (MPEC) is an attractive method to control mycelial morphology, and thus enhance the production of metabolites and enzymes in the submerged cultivations of filamentous fungi. Unfortunately, most literature data deals with the spore-agglomerating species like aspergilli. Therefore, the detailed quantitative study of the morphological evolution of four different fungal species (Aspergillus terreus, Penicillium rubens, Chaetomium globosum, and Mucor racemosus) based on the digital analysis of microscopic images was presented in this paper. In accordance with the current knowledge, these species exhibit different mechanisms of agglomerates formation. The standard submerged shake flask cultivations (as a reference) and MPEC involving 10 μm aluminum oxide microparticles (6 g·L -1 ) were performed. The morphological parameters, including mean projected area, elongation, roughness, and morphology number were determined for the mycelial objects within the first 24 hr of growth. It occurred that heretofore observed and widely discussed effect of microparticles on fungi, namely the decrease in pellet size, was not observed for the species whose pellet formation mechanism is different from spore agglomeration. In the MPEC, C. globosum developed core-shell pellets, and M. racemosus, a nonagglomerative species, formed the relatively larger, compared to standard cultures, pellets with distinct cores. © 2018 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

JV Task 108 - Circulating Fluidized-Bed Combustion and Combustion Testing of Turkish Tufanbeyli Coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Douglas Hajicek; Jay Gunderson; Ann Henderson

2007-08-15

Two combustion tests were performed at the Energy & Environmental Research Center (EERC) using Tufanbeyli coal from Turkey. The tests were performed in a circulating fluidized-bed combustor (CFBC) and a pulverized coal-fired furnace, referred to as the combustion test facility (CTF). One of the goals of the project was to determine the type of furnace best suited to this coal. The coal is high in moisture, ash, and sulfur and has a low heating value. Both the moisture and the sulfur proved problematic for the CTF tests. The fuel had to be dried to less than 37% moisture before itmore » could be pulverized and further dried to about 25% moisture to allow more uniform feeding into the combustor. During some tests, water was injected into the furnace to simulate the level of flue gas moisture had the fuel been fed without drying. A spray dryer was used downstream of the baghouse to remove sufficient sulfur to meet the EERC emission standards permitted by the North Dakota Department of Health. In addition to a test matrix varying excess air, burner swirl, and load, two longer-term tests were performed to evaluate the fouling potential of the coal at two different temperatures. At the lower temperature (1051 C), very little ash was deposited on the probes, but deposition did occur on the walls upstream of the probe bank, forcing an early end to the test after 2 hours and 40 minutes of testing. At the higher temperature (1116 C), ash deposition on the probes was significant, resulting in termination of the test after only 40 minutes. The same coal was burned in the CFBC, but because the CFBC uses a larger size of material, it was able to feed this coal at a higher moisture content (average of 40.1%) compared to the CTF (ranging from 24.2% to 26.9%). Sulfur control was achieved with the addition of limestone to the bed, although the high calcium-to-sulfur rate required to reduce SO{sub 2} emissions resulted in heat loss (through limestone calcination) and additional ash handling. A more efficient downstream sulfur scrubber capable of operation at a much lower Ca/S ratio would result in significantly higher boiler efficiency for this coal. At the operating temperature of a typical CFBC, bed agglomeration and convective pass fouling are not likely to be significant problems with this fuel. Compared to pulverized coal-firing, CFBC technology is clearly the better choice for this fuel. It provides more efficient sulfur capture, lower NO{sub x} emissions, better solids-handling capability, and can utilize a wetter feedstock, requiring less crushing and sizing. The lower operating temperature of CFBC boilers (820 C) reduces the risk of fouling and agglomeration. Care must be taken to minimize heat loss in the system to accommodate the low heating value of the coal.« less

Interspecific variation in resistance to emerald ash borer (Coleoptera: Buprestidae) among North American and Asian ash (Fraxinus spp.).

PubMed

Rebek, Eric J; Herms, Daniel A; Smitley, David R

2008-02-01

We conducted a 3-yr study to compare the susceptibility of selected North American ash and an Asian ash species to emerald ash borer, Agrilus planipennis Fairmaire, an invasive wood-boring beetle introduced to North America from Asia. Because of a coevolutionary relationship between Asian ashes and emerald ash borer, we hypothesized an Asian ash species, Manchurian ash, is more resistant to the beetle than its North American congeners. Consistent with our hypothesis, Manchurian ash experienced far less mortality and yielded far fewer adult beetles than several cultivars of North American green and white ash. Surprisingly, a black ash (North American) x Manchurian ash hybrid was highly susceptible to emerald ash borer, indicating this cultivar did not inherit emerald ash borer resistance from its Asian parent. A corollary study investigated the efficacy of soil-applied imidacloprid, a systemic, neonicotinoid insecticide, for controlling emerald ash borer in each of the five cultivars. Imidacloprid had no effect on emerald ash borer colonization of Manchurian ash, which was low in untreated and treated trees. In contrast, imidacloprid did enhance survival of the North American and hybrid cultivars and significantly reduced the number of emerald ash borer adults emerging from green and white ash cultivars. We identify a possible mechanism of resistance of Manchurian ash to emerald ash borer, which may prove useful for screening, selecting, and breeding emerald ash borer-resistant ash trees.

Polymer Nanocomposite Materials with High Dielectric Permittivity and Low Dielectric Loss Properties

NASA Astrophysics Data System (ADS)

Toor, Anju

Materials with high dielectric permittivity have drawn increasing interests in recent years for their important applications in capacitors, actuators, and high energy density pulsed power. Particularly, polymer-based dielectrics are excellent candidates, owing to their properties such as high breakdown strength, low dielectric loss, flexibility and easy processing. To enhance the dielectric permittivity of polymer materials, typically, high dielectric constant filler materials are added to the polymer. Previously, ferroelectric and conductive fillers have been mainly used. However, such systems suffered from various limitations. For example, composites based on ferroelectric materials like barium titanate, exhibited high dielectric loss, and poor saturation voltages. Conductive fillers are used in the form of powder aggregates, and they may show 10-100 times enhancement in dielectric constant, however these nanoparticle aggregates cause the dielectric loss to be significant. Also, agglomerates limit the volume fraction of fillers in polymer and hence, the ability to achieve superior dielectric constants. Thus, the aggregation of nanoparticles is a significant challenge to their use to improve the dielectric permittivity. We propose the use of ligand-coated metal nanoparticle fillers to enhance the dielectric properties of the host polymer while minimizing dielectric loss by preventing nanoparticle agglomeration. The focus is on obtaining uniform dispersion of nanoparticles with no agglomeration by utilizing appropriate ligands/surface functionalizations on the gold nanoparticle surface. Use of ligand coated metal nanoparticles will enhance the dielectric constant while minimizing dielectric loss, even with the particles closely packed in the polymer matrix. Novel combinations of materials, which use 5 nm diameter metal nanoparticles embedded inside high breakdown strength polymer materials are evaluated. High breakdown strength polymer materials are chosen to allow further exploration of these materials for energy storage applications. In summary, two novel nanocomposite materials are designed and synthesized, one involving polyvinylidene fluoride (PVDF) as the host polymer for potential applications in energy storage and the other with SU-8 for microelectronic applications. Scanning elec- tron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy and ultramicrotoming techniques were used for the material characterization of the nanocomposite materials. A homogeneous dispersion of gold nanoparticles with low particle agglomeration has been achieved. Fabricated nanoparticle polymer composite films showed the absence of voids and cracks. Also, no evidence of macro-phase separation of nanoparticles from the polymer phase was observed. This is important because nanoparticle agglomeration and phase separation from the polymer usually results in poor processability of films and a high defect density. Dielectric characterization of the nanocomposite materials showed enhancement in the dielectric constant over the base polymer values and low dielectric loss values were observed.

Use of weathered and fresh bottom ash mix layers as a subbase in road constructions: environmental behavior enhancement by means of a retaining barrier.

PubMed

Del Valle-Zermeño, R; Chimenos, J M; Giró-Paloma, J; Formosa, J

2014-12-01

The presence of neoformed cement-like phases during the weathering of non-stabilized freshly quenched bottom ash favors the development of a bound pavement material with improved mechanical properties. Use of weathered and freshly quenched bottom ash mix layers placed one over the other allowed the retention of leached heavy metals and metalloids by means of a reactive percolation barrier. The addition of 50% of weathered bottom ash to the total subbase content diminished the release of toxic species to below environmental regulatory limits. The mechanisms of retention and the different processes and factors responsible of leaching strongly depended on the contaminant under concern as well as on the chemical and physical factors. Thus, the immediate reuse of freshly quenched bottom ash as a subbase material in road constructions is possible, as both the mechanical properties and long-term leachability are enhanced. Copyright © 2014 Elsevier Ltd. All rights reserved.

Validating the MFiX-DEM Model for Flow Regime Prediction in a 3D Spouted Bed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Banerjee, Subhodeep; Guenther, Chris; Rogers, William A.

The spout-fluidized bed reactor with relatively large oxygen carrier particles offers several advantages in chemical looping combustion operation using solid fuels. The large difference in size and weight between the oxygen carrier particles and the smaller coal or ash particles allows the oxygen carrier to be easily segregated for recirculation; the increased solids mixing due to dynamic flow pattern in the spout-fluidization regime prevents agglomeration. The primary objective in this work is to determine the effectiveness of the MFiX-DEM model in predicting the flow regime in a spouted bed. Successful validation of the code will allow the user to finemore » tune the operating conditions of a spouted bed to achieve the desired operating condition.« less

Characteristics of silica rice husk ash from Mojogedang Karanganyar Indonesia

NASA Astrophysics Data System (ADS)

Suryana, R.; Iriani, Y.; Nurosyid, F.; Fasquelle, D.

2018-05-01

Indonesia is one of the countries in the world as the most abundant rice producer. Many researchers have demonstrated that the highest composition in the rice husk ash (RHA) is silica. Some of the advantages in utilizing silica as the raw material is the manufacture of ceramics, zeolite synthesis, fabrication of glass, electronic insulator materials, and as a catalyst. The amount of silica from rice husk ash is different for each region. Therefore, the study of silica from RHA is still promising, especially rice organic fertilizers. In this study, the rice came from Mojogedang Karanganyar Indonesia. Rice husk was dried under the solar radiation. Then the rice husk was heated in two steps: the first step at a temperature of 300°C and the second step at a temperature of 1200°C with a holding time at 2 h and 1 h, respectively. Furthermore, the temperature of the second step was varied at 1400 °C and 1600 °C. This heating process produced RHA. The content of RHA was observed on the EDAX spectrums while the morphology was observed from SEM images. The crystal structure of RHA was determined from XRD spectrums. The EDAX spectrums showed that RHA composition was dominated by elements Si and O for all the heating temperature. SEM images showed an agglomeration towards larger domains as heating temperatures increase. Analysis of XRD spectra is polycrystalline silica formed with the significant crystal orientation at 101, 102 and 200. The intensity of 101 increases significantly with increasing temperature. It is concluded that the crystal growth in the direction of 101 is preferred.

Eco-friendly fly ash utilization: potential for land application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malik, A.; Thapliyal, A.

2009-07-01

The increase in demand for power in domestic, agricultural, and industrial sectors has increased the pressure on coal combustion and aggravated the problem of fly ash generation/disposal. Consequently the research targeting effective utilization of fly ash has also gained momentum. Fly ash has proved to be an economical substitute for expensive adsorbents as well as a suitable raw material for brick manufacturing, zeolite synthesis, etc. Fly ash is a reservoir of essential minerals but is deficient in nitrogen and phosphorus. By amending fly ash with soil and/or various organic materials (sewage sludge, bioprocess materials) as well as microbial inoculants likemore » mycorrhizae, enhanced plant growth can be realized. Based on the sound results of large scale studies, fly ash utilization has grown into prominent discipline supported by various internationally renowned organizations. This paper reviews attempts directed toward various utilization of fly ash, with an emphasis on land application of organic/microbial inoculants amended fly ash.« less

Efficient solid rocket propulsion for access to space

NASA Astrophysics Data System (ADS)

Maggi, Filippo; Bandera, Alessio; Galfetti, Luciano; De Luca, Luigi T.; Jackson, Thomas L.

2010-06-01

Space launch activity is expected to grow in the next few years in order to follow the current trend of space exploitation for business purpose. Granting high specific thrust and volumetric specific impulse, and counting on decades of intense development, solid rocket propulsion is a good candidate for commercial access to space, even with common propellant formulations. Yet, some drawbacks such as low theoretical specific impulse, losses as well as safety issues, suggest more efficient propulsion systems, digging into the enhancement of consolidated techniques. Focusing the attention on delivered specific impulse, a consistent fraction of losses can be ascribed to the multiphase medium inside the nozzle which, in turn, is related to agglomeration; a reduction of agglomerate size is likely. The present paper proposes a model based on heterogeneity characterization capable of describing the agglomeration trend for a standard aluminized solid propellant formulation. Material microstructure is characterized through the use of two statistical descriptors (pair correlation function and near-contact particles) looking at the mean metal pocket size inside the bulk. Given the real formulation and density of a propellant, a packing code generates the material representative which is then statistically analyzed. Agglomerate predictions are successfully contrasted to experimental data at 5 bar for four different formulations.

Water-assisted growth of graphene-carbon nanotube hybrids in plasma

NASA Astrophysics Data System (ADS)

Tewari, Aarti; Ghosh, Santanu; Srivastava, Pankaj

2018-04-01

The enhanced growth of graphene-carbon nanotube (CNT) hybrids in a hydrocarbon and hydrogen plasma assisted by water is numerically formulated. The catalyst activity and agglomeration of catalyst particles are the rate determining factors in the growth of hybrids and their constituents, i.e., the CNT and graphene. The water vapor concentration is varied to investigate its effect on the growth process. The enhanced catalyst activity on account of oxidation by hydroxyl ions of water to impede the agglomeration of catalyst particles and the removal of amorphous carbon through etching by hydrogen ions of water are seen to be the main driving forces behind the many fold increase in the dimensions of constituent nanostructures and the hybrids with water vapor concentration. Importantly, beyond a certain specific water vapor concentration, the growth rates dropped due to active oxidation of the catalyst particle.

Separation of particulate from flue gas of fossil fuel combustion and gasification

DOEpatents

Yang, Wen-Ching; Newby, Richard A.; Lippert, Thomas E.

1997-01-01

The gas from combustion or gasification of fossil fuel contains flyash and other particulate. The flyash is separated from the gas in a plurality of standleg moving granular-bed filter modules. Each module includes a dipleg through which the bed media flows into the standleg. The bed media forms a first filter bed having an upper mass having a first frusto-conical surface in a frusto-conical member at the entrance to the standleg and a lower mass having a second frusto-conical surface of substantially greater area than the first surface after it passes through the standleg. A second filter media bed may be formed above the first filter media bed. The gas is fed tangentially into the module above the first surface. The flyash is captured on the first frusto-conical surface and within the bed mass. The processed gas flows out through the second frusto-conical surface and then through the second filter bed, if present. The bed media is cleaned of the captured flyash and recirculated to the moving granular bed filter. Alternatively, the bed media may be composed of the ash from the combustion which is pelletized to form agglomerates. The ash flows through the bed only once; it is not recycled.

Prewashing enhances the liquid hot water pretreatment efficiency of waste wheat straw with high free ash content.

PubMed

Huang, Chen; Wu, Xinxing; Huang, Yang; Lai, Chenhuan; Li, Xin; Yong, Qiang

2016-11-01

The effect of prewashing process prior to the liquid hot water (LHW) pretreatment of high free ash content waste wheat straw (WWS) was investigated. It was found that prewashing process decreased the ash content of WWS greatly, from 29.48% to 9.82%. This contributed to the lower pH value of prehydrolyzate and higher xylan removal in the following LHW pretreatment. More importantly, the prewashing process effectively increased the cellulose enzymatic hydrolysis efficiency of pretreated WWS, from 53.04% to 84.15%. The acid buffering capacity (ABC) and cation exchange capacity (CEC) of raw and prewashed WWS were examined. The majority of free ash removal from WWS by prewashing resulted in the decrease of the ABC of the WWS from 211.74 to 61.81mmol/pH-kg, and potentially enhancing the efficiency of the follow-up LHW pretreatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparing Two Independent Satellite-Based Algorithms for Detecting and Tracking Ash Clouds by Using SEVIRI Sensor.

PubMed

Falconieri, Alfredo; Cooke, Michael C; Filizzola, Carolina; Marchese, Francesco; Pergola, Nicola; Tramutoli, Valerio

2018-01-27

The Eyjafjallajökull (Iceland) volcanic eruption of April-May 2010 caused unprecedented air-traffic disruption in Northern Europe, revealing some important weaknesses of current operational ash-monitoring and forecasting systems and encouraging the improvement of methods and procedures for supporting the activities of Volcanic Ash Advisory Centers (VAACs) better. In this work, we compare two established satellite-based algorithms for ash detection, namely RST ASH and the operational London VAAC method, both exploiting sensor data of the spinning enhanced visible and infrared imager (SEVIRI). We analyze similarities and differences in the identification of ash clouds during the different phases of the Eyjafjallajökull eruption. The work reveals, in some cases, a certain complementary behavior of the two techniques, whose combination might improve the identification of ash-affected areas in specific conditions. This is indicated by the quantitative comparison of the merged SEVIRI ash product, achieved integrating outputs of the RST ASH and London VAAC methods, with independent atmospheric infrared sounder (AIRS) DDA (dust-detection algorithm) observations.

Effect of temperature on the hydration of Portland cement blended with siliceous fly ash

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deschner, Florian, E-mail: florian.deschner@gmail.com; Lothenbach, Barbara; Winnefeld, Frank

2013-10-15

The effect of temperature on the hydration of Portland cement pastes blended with 50 wt.% of siliceous fly ash is investigated within a temperature range of 7 to 80 °C. The elevation of temperature accelerates both the hydration of OPC and fly ash. Due to the enhanced pozzolanic reaction of the fly ash, the change of the composition of the C–S–H and the pore solution towards lower Ca and higher Al and Si concentrations is shifted towards earlier hydration times. Above 50 °C, the reaction of fly ash also contributes to the formation of siliceous hydrogarnet. At 80 °C, ettringitemore » and AFm are destabilised and the released sulphate is partially incorporated into the C–S–H. The observed changes of the phase assemblage in dependence of the temperature are confirmed by thermodynamic modelling. The increasingly heterogeneous microstructure at elevated temperatures shows an increased density of the C–S–H and a higher coarse porosity. -- Highlights: •The reaction of quartz powder at 80 °C strongly enhances the compressive strength. •Almost no strength increase of fly ash blended OPC at 80 °C was found after 2 days. •Siliceous hydrogarnet is formed upon the reaction of fly ash at high temperatures. •Temperature dependent change of the system was simulated by thermodynamic modelling. •Destabilisation of ettringite above 50 °C correlates with sulphate content of C–S–H.« less

Microstructure and wear characterization of aluminum matrix composites reinforced with industrial waste fly ash particulates synthesized by friction stir processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dinaharan, I., E-mail: dinaweld2009@gmail.com

Fly ash (FA) is a waste product of coal combustion in thermal power plants which is available in massive quantities all over the world causing land pollution. This paper reports the characterization of AA6061 aluminum matrix composites (AMCs) reinforced with FA particles synthesized using friction stir processing (FSP). The volume fraction of FA particles was varied from 0 to 18 in steps of 6. The prepared AMCs were characterized using optical microscopy (OM), scanning electron microscopy (SEM) and electron backscattered diagram (EBSD). The wear rate was estimated using a pin-on-disc wear apparatus. FA particles were observed to be distributed homogeneouslymore » in the AMC irrespective of the location within the stir zone. The EBSD micrographs revealed remarkable grain refinement in the AMC. The incorporation of FA particles enhanced the microhardness and wear resistance of the AMC. The strengthening mechanisms of the AMC were discussed and correlated to the observed microstructures. The wear mechanisms were identified by characterizing the wear debris and worn surfaces. - Highlights: •Industrial waste fly ash was used to produce aluminum matrix composites. •Friction stir processing was used to produce AA6061/Fly Ash composite. •Fly ash particles refined the grains of aluminum matrix. •Fly ash particles enhanced the hardness and wear resistance. •Successful utilization of fly ash to make aluminum composites reduces land pollution.« less

Use of solid residue from thermal power plant (fly ash) for enhancing sewage sludge anaerobic digestion: Influence of fly ash particle size.

PubMed

Montalvo, S; Cahn, I; Borja, R; Huiliñir, C; Guerrero, L

2017-11-01

The influence of fly ash particle size on methane production and anaerobic biodegradability was evaluated. Assays with different fly ash particle sizes (0.8-2.36mm) at a concentration of 50mg/L were ran under mesophilic conditions. In anaerobic processes operating with fly ash, greater removal of both volatile total and suspended solids, chemical oxygen demand (total and soluble) was achieved, with an increase of methane production between 28% and 96% compared to the control reactors. The highest increase occurred at ash particles sizes of 1.0-1.4mm. The metal concentrations in the digestates obtained after anaerobic digestion of sewage sludge are far below those considered as limiting for the use of sludge in soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

Carbon, oxygen and their interaction with intrinsic point defects in solar silicon ribbon material: A speculative approach

NASA Technical Reports Server (NTRS)

Goesele, U.; Ast, D. G.

1983-01-01

Some background information on intrinsic point defects is provided and on carbon and oxygen in silicon in so far as it may be relevant for the efficiency of solar cells fabricated from EFG ribbon material. The co-precipitation of carbon and oxygen and especially of carbon and silicon self interstitials are discussed. A simple model for the electrical activity of carbon-self-interstitial agglomerates is presented. The self-interstitial content of these agglomerates is assumed to determine their electrical activity and that both compressive stresses (high self-interstitial content) and tensile stresses (low self-interstitial content) give rise to electrical activity of the agglomerates. The self-interstitial content of these carbon-related agglomerates may be reduced by an appropriate high temperature treatment and enhanced by a supersaturation of self-interstitials generated during formation of the p-n junction of solar cells. Oxygen present in supersaturation in carbon-rich silicon may be induced to form SiO, precipitates by self-interstitials generated during phosphorus diffusion. It is proposed that the SiO2-Si interface of the precipates gives rise to a continuum of donor stables and that these interface states are responsible for at least part of the light inhancement effects observed in oxygen containing EFG silicon after phosphorus diffusion.

Oriented nanofibers embedded in a polymer matrix

NASA Technical Reports Server (NTRS)

Barrera, Enrique V. (Inventor); Lozano, Karen (Inventor); Rodriguez-Macias, Fernando J. (Inventor); Chibante, Luis Paulo Felipe (Inventor); Stewart, David Harris (Inventor)

2011-01-01

A method of forming a composite of embedded nanofibers in a polymer matrix is disclosed. The method includes incorporating nanofibers in a plastic matrix forming agglomerates, and uniformly distributing the nanofibers by exposing the agglomerates to hydrodynamic stresses. The hydrodynamic said stresses force the agglomerates to break apart. In combination or additionally elongational flow is used to achieve small diameters and alignment. A nanofiber reinforced polymer composite system is disclosed. The system includes a plurality of nanofibers that are embedded in polymer matrices in micron size fibers. A method for producing nanotube continuous fibers is disclosed. Nanofibers are fibrils with diameters of 100 nm, multiwall nanotubes, single wall nanotubes and their various functionalized and derivatized forms. The method includes mixing a nanofiber in a polymer; and inducing an orientation of the nanofibers that enables the nanofibers to be used to enhance mechanical, thermal and electrical properties. Orientation is induced by high shear mixing and elongational flow, singly or in combination. The polymer may be removed from said nanofibers, leaving micron size fibers of aligned nanofibers.

Mutations in ash1 and trx enhance P-element-dependent silencing in Drosophila melanogaster.

PubMed

McCracken, Allen; Locke, John

2016-08-01

In Drosophila melanogaster, the mini-w(+) transgene in Pci is normally expressed throughout the adult eye; however, when other P or KP elements are present, a variegated-eye phenotype results, indicating random w(+) silencing during development called P-element-dependent silencing (PDS). Mutant Su(var)205 and Su(var)3-7 alleles act as haplo-suppressors/triplo-enhancers of this variegated phenotype, indicating that these heterochromatic modifiers act dose dependently in PDS. Previously, we recovered a spontaneous mutation of P{lacW}ci(Dplac) called P{lacW}ci(DplacE1) (E1) that variegated in the absence of P elements, presumably due to the insertion of an adjacent gypsy element. From a screen for genetic modifiers of E1 variegation, we describe here the isolation of five mutations in ash1 and three in trx that enhance the E1 variegated phenotype in a dose-dependent and cumulative manner. These mutant alleles enhance PDS at E1, and in E1/P{lacW}ci(Dplac), but suppress position effect variegation (PEV) at In(1)w(m)(4). This opposite action is consistent with a model where ASH1 and TRX mark transcriptionally active chromatin domains. If ASH1 or TRX function is lost or reduced, heterochromatin can spread into these domains creating a sink that diverts heterochromatic proteins from other variegating locations, which then may express a suppressed phenotype.

Arsenic removal from water using a novel amorphous adsorbent developed from coal fly ash.

PubMed

Zhang, Kaihua; Zhang, Dongxue; Zhang, Kai

2016-01-01

A novel effective adsorbent of alumina/silica oxide hydrate (ASOH) for arsenic removal was developed through simple chemical reactions using coal fly ash. The iron-modified ASOH with enhancing adsorption activity was further developed from raw fly ash based on the in situ technique. The adsorbents were characterized by X-ray diffraction, Fourier transform infrared spectrometry, scanning electron micrograph, laser particle size and Brunauer-Emmet-Teller surface area. The results show that the adsorbents are in amorphous and porous structure, the surface areas of which are 8-12 times that of the raw ash. The acidic hydrothermal treatment acts an important role in the formation of the amorphous structure of ASOH rather than zeolite crystal. A series of adsorption experiments for arsenic on them were studied. ASOH can achieve a high removal efficiency for arsenic of 96.4% from water, which is more than 2.5 times that of the raw ash. Iron-modified ASOH can enhance the removal efficiency to reach 99.8% due to the in situ loading of iron (Fe). The condition of synthesis pH = 2-4 is better for iron-modified ASOH to adsorb arsenic from water.

Aerosol properties and meteorological conditions in the city of Buenos Aires, Argentina, during the resuspension of volcanic ash from the Puyehue-Cordón Caulle eruption

NASA Astrophysics Data System (ADS)

Graciela Ulke, Ana; Torres Brizuela, Marcela M.; Raga, Graciela B.; Baumgardner, Darrel

2016-09-01

The eruption in June 2011 of the Puyehue-Cordón Caulle Volcanic Complex in Chile impacted air traffic around the Southern Hemisphere for several months after the initial ash emissions. The ash deposited in vast areas of the Patagonian Steppe was subjected to the strong wind conditions prevalent during the austral winter and spring experiencing resuspension over various regions of Argentina. In this study we analyze the meteorological conditions that led to the episode of volcanic ash resuspension which impacted the city of Buenos Aires and resulted in the closure of the two main airports in Buenos Aires area (Ezeiza and Aeroparque) on 16 October 2011. A relevant result is that resuspended material (volcanic ash plus dust) imprints a distinguishable feature within the atmospheric thermodynamic vertical profiles. The thermodynamic soundings show the signature of "pulses of drying" in layers associated with the presence of hygroscopic ash in the atmosphere that has already been reported in similar episodes after volcanic eruptions in other parts of the world. This particular footprint can be used to detect the probable existence of volcanic ash layers. This study also illustrates the utility of ceilometers to detect not only cloud base at airports but also volcanic ash plumes at the boundary layer and up to 7 km altitude. Aerosol properties measured in the city during the resuspension episode indicate the presence of enhanced concentrations of aerosol particles in the boundary layer along with spectral signatures in the measurements at the Buenos Aires AERONET site typical of ash plus dust advected towards the city. The mandatory aviation reports from the National Weather Service about airborne and deposited volcanic ash at the airport near the measurement site (Aeroparque) correlate in time with the enhanced concentrations. The presence of the resuspended material was detected by the CALIOP lidar overpassing the region. Since the dynamics of ash resuspension and recirculation are similar to the dynamics of dust storms, we use the HYSPLIT model with the dust storm module to simulate the episode that affected Buenos Aires. The results of the modeling agree qualitatively with satellite lidar measurements.

Mercury capture by native fly ash carbons in coal-fired power plants

PubMed Central

Hower, James C.; Senior, Constance L.; Suuberg, Eric M.; Hurt, Robert H.; Wilcox, Jennifer L.; Olson, Edwin S.

2013-01-01

The control of mercury in the air emissions from coal-fired power plants is an on-going challenge. The native unburned carbons in fly ash can capture varying amounts of Hg depending upon the temperature and composition of the flue gas at the air pollution control device, with Hg capture increasing with a decrease in temperature; the amount of carbon in the fly ash, with Hg capture increasing with an increase in carbon; and the form of the carbon and the consequent surface area of the carbon, with Hg capture increasing with an increase in surface area. The latter is influenced by the rank of the feed coal, with carbons derived from the combustion of low-rank coals having a greater surface area than carbons from bituminous- and anthracite-rank coals. The chemistry of the feed coal and the resulting composition of the flue gas enhances Hg capture by fly ash carbons. This is particularly evident in the correlation of feed coal Cl content to Hg oxidation to HgCl2, enhancing Hg capture. Acid gases, including HCl and H2SO4 and the combination of HCl and NO2, in the flue gas can enhance the oxidation of Hg. In this presentation, we discuss the transport of Hg through the boiler and pollution control systems, the mechanisms of Hg oxidation, and the parameters controlling Hg capture by coal-derived fly ash carbons. PMID:24223466

Transformation of CuO Nanoparticles in the Aquatic Environment: Influence of pH, Electrolytes and Natural Organic Matter

PubMed Central

Peng, Cheng; Shen, Chensi; Zheng, Siyuan; Yang, Weiling; Hu, Hang; Liu, Jianshe; Shi, Jiyan

2017-01-01

Many studies have shown the effect of solution chemistry on the environmental behavior of metal-based nanoparticles (NPs), except CuO NPs. Here, we investigated the agglomeration, sedimentation, dissolution, and speciation of CuO NPs by varying pH, ionic strength, ionic valence, and natural organic matter (NOM). The results showed that as the pH moved away from 6, the size of CuO agglomerates decreased, along with the enhanced NP suspension stabilization, due to the increase of electrostatic repulsive force. Increasing ionic strength and valence intensified the agglomeration and sedimentation of CuO NPs because of the compression of electrical double layers. The presence of humic acid and citric acid enhanced the dispersion and stabilization of CuO NP suspension, but l-cysteine showed a different impact. Decreasing pH, increasing ionic strength and all NOM improved the dissolution of CuO NPs, but the divalent electrolyte (CaCl2) inhibited the Cu2+ release from CuO NPs compared to the monovalent electrolyte (NaCl). In addition, X-ray absorption near edge structure (XANES) analysis demonstrated that the presence of l-cysteine transformed more than 30% of CuO NPs to Cu(I)-cysteine by coordinating with thiol group. This study can give us an in-depth understanding on the environmental behavior and fate of CuO NPs in the aquatic environment. PMID:29036921

Reduction of carbon content in waste-tire combustion ashes by bio-thermal treatment.

PubMed

Chen, Chun-Chi; Lee, Wen-Jhy; Shih, Shun-I; Mou, Jin-Luh

2009-11-01

Application of bio-catalyst (NOE-7F) in thermal treatment can adequately dispose dark-black fly ashes from co-combustion of both waste tires and coal. After thermal treatment of fly ashes by adding 10% NOE-7F, the carbon contents reduced by 37.6% and the weight losses increased by 405%, compared with the fly ashes without mixing with NOE-7F. The combustion behaviors of wasted tires combustion fly ashes with NOE-7F were also investigated by both thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The results verify that NOE-7F has positive effects on the combustion of residual carbon and toxic polycyclic aromatic hydrocarbons (PAHs) enhance the energy release and reduce the toxicity during the process of thermal treatment. Furthermore, using NOE-7F to dispose high-carbon content fly ashes did improve the compressive strength of fly ashes and concrete mixtures. Therefore, NOE-7F is a promising additive which could decrease treatment cost of high-carbon content fly ashes and reduce the amount of survival toxic PAHs.

Reduction of carbon content in waste-tire combustion ashes by bio-thermal treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, C.C.; Lee, W.J.; Shih, S.I.

2009-07-01

Application of bio-catalyst (NOE-7F) in thermal treatment can adequately dispose dark-black fly ashes from co-combustion of both waste tires and coal. After thermal treatment of fly ashes by adding 10% NOE-7F, the carbon contents reduced by 37.6% and the weight losses increased by 405%, compared with the fly ashes without mixing with NOE-7F. The combustion behaviors of wasted tires combustion fly ashes with NOE-7F were also investigated by both thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The results verify that NOE-7F has positive effects on the combustion of residual carbon and toxic polycyclic aromatic hydrocarbons (PAHs) enhance the energymore » release and reduce the toxicity during the process of thermal treatment. Furthermore, using NOE-7F to dispose high-carbon content fly ashes did improve the compressive strength of fly ashes and concrete mixtures. Therefore, NOE-7F is a promising additive which could decrease treatment cost of high-carbon content fly ashes and reduce the amount of survival toxic PAHs.« less

Phosphate-enhanced cytotoxicity of zinc oxide nanoparticles and agglomerates.

PubMed

Everett, W Neil; Chern, Christina; Sun, Dazhi; McMahon, Rebecca E; Zhang, Xi; Chen, Wei-Jung A; Hahn, Mariah S; Sue, H-J

2014-02-10

Zinc oxide (ZnO) nanoparticles (NPs) have been found to readily react with phosphate ions to form zinc phosphate (Zn3(PO4)2) crystallites. Because phosphates are ubiquitous in physiological fluids as well as waste water streams, it is important to examine the potential effects that the formation of Zn3(PO4)2 crystallites may have on cell viability. Thus, the cytotoxic response of NIH/3T3 fibroblast cells was assessed following 24h of exposure to ZnO NPs suspended in media with and without the standard phosphate salt supplement. Both particle dosage and size have been shown to impact the cytotoxic effects of ZnO NPs, so doses ranging from 5 to 50 μg/mL were examined and agglomerate size effects were investigated by using the bioinert amphiphilic polymer polyvinylpyrrolidone (PVP) to generate water-soluble ZnO ranging from individually dispersed 4 nm NPs up to micron-sized agglomerates. Cell metabolic activity measures indicated that the presence of phosphate in the suspension media can led to significantly reduced cell viability at all agglomerate sizes and at lower ZnO dosages. In addition, a reduction in cell viability was observed when agglomerate size was decreased, but only in the phosphate-containing media. These metabolic activity results were reflected in separate measures of cell death via the lactate dehydrogenase assay. Our results suggest that, while higher doses of water-soluble ZnO NPs are cytotoxic, the presence of phosphates in the surrounding fluid can lead to significantly elevated levels of cell death at lower ZnO NP doses. Moreover, the extent of this death can potentially be modulated or offset by tuning the agglomerate size. These findings underscore the importance of understanding how nanoscale materials can interact with the components of surrounding fluids so that potential adverse effects of such interactions can be controlled. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Stability of volcanic ash aggregates and break-up processes.

PubMed

Mueller, Sebastian B; Kueppers, Ulrich; Ametsbichler, Jonathan; Cimarelli, Corrado; Merrison, Jonathan P; Poret, Matthieu; Wadsworth, Fabian B; Dingwell, Donald B

2017-08-07

Numerical modeling of ash plume dispersal is an important tool for forecasting and mitigating potential hazards from volcanic ash erupted during explosive volcanism. Recent tephra dispersal models have been expanded to account for dynamic ash aggregation processes. However, there are very few studies on rates of disaggregation during transport. It follows that current models regard ash aggregation as irrevocable and may therefore overestimate aggregation-enhanced sedimentation. In this experimental study, we use industrial granulation techniques to artificially produce aggregates. We subject these to impact tests and evaluate their resistance to break-up processes. We find a dependence of aggregate stability on primary particle size distribution and solid particle binder concentration. We posit that our findings could be combined with eruption source parameters and implemented in future tephra dispersal models.

Removal of strontium from drinking water by conventional treatment and lime softening in bench-scale studies.

PubMed

O'Donnell, Alissa J; Lytle, Darren A; Harmon, Stephen; Vu, Kevin; Chait, Hannah; Dionysiou, Dionysios D

2016-10-15

The United States Environmental Protection Agency Contaminant Candidate List 3 lists strontium as a contaminant for potential regulatory consideration in drinking water. Very limited data is available on strontium removal from drinking water and as a result, there is an immediate need for treatment information. The objective of this work is to evaluate the effectiveness of coagulation/filtration and lime-soda ash softening treatment methods to remove strontium from surface and ground waters. Coagulation/filtration jar test results on natural waters showed that conventional treatment with aluminum and iron coagulants were able to achieve only 12% and 5.9% strontium removal, while lime softening removed as high as 78% from natural strontium-containing ground water. Controlled batch experiments on synthetic water showed that strontium removal during the lime-soda ash softening was affected by pH, calcium concentration and dissolved inorganic carbon concentration. In all softening jar tests, the final strontium concentration was directly related to the initial strontium concentration and the removal of strontium was directly associated with calcium removal. Precipitated solids showed well-formed crystals or agglomerates of mixed solids, two polymorphs of calcium carbonate (vaterite and calcite), and strontianite, depending on initial water quality conditions. X-ray diffraction analysis suggested that strontium was likely incorporated in the calcium carbonate crystal lattice and was likely responsible for removal during lime softening. Copyright © 2016. Published by Elsevier Ltd.

Pulse combusted acoustic agglomeration apparatus and process

DOEpatents

Mansour, Momtaz N.; Chandran, Ravi

1994-01-01

An improved apparatus and process for removal of particulates entrained in a gas stream are provided. The removal process employs a pulse combustor to provide an acoustic pressure wave to acoustically enhance agglomeration of particulates which may be collected and removed using a conventional separation apparatus. The apparatus may be employed as a direct fired system for improved operation of gas-operated equipment such as a gas turbine, or may, alternatively, be employed as an add-on subsystem for combustion exhaust clean-up. Additionally, added particulates may include a sorbent for effecting sorption of other contaminants such as sulfur. Various other particulates for contaminant removal may also be introduced into the system as exemplified by alkali-gettering agents.

Microstructure and hardness performance of AA6061 aluminium composite using friction stir processing

NASA Astrophysics Data System (ADS)

Marini, C. D.; Fatchurrohman, N.

2018-04-01

Rice husk ash (RHA) is an industrial waste that has become a potential reinforced material for aluminium matrix composite (AMCs) due to low cost and abundantly available resources. Friction stir processing (FSP) has been introduced as a method to modify surface properties of the metal and alloy including theirs composite as well. The present work reports the production and characterization of AA6061 and AA6061/5 vol% RHA using FSP using parameters rotation speed 1000 rpm and traversed speed 25 mm/min. The microstructure was studied using optical microscopy (OM). A homogenous dispersion of RHA particles was obtained in the composite. No agglomeration or segregation was observed. The produced composite exhibited a fine grain structure. An improvement in hardness profile was observed as AA6061/5 vol% RHA improves in hardness compared to FSPed of AA6061 without reinforcement.

Wood ash residue causes a mixture of growth promotion and toxicity in Lemna minor.

PubMed

Jagodzinski, Lucas S; O'Donoghue, Marian T; Heffernan, Liam B; van Pelt, Frank N A M; O'Halloran, John; Jansen, Marcel A K

2018-06-01

The use of wood as a sustainable biofuel results in the generation of residual wood ash. The ash contains high amounts of plant macronutrients such as phosphorus, potassium, calcium as well as several micronutrients. To explore the potential use of wood ash as a fertiliser, the growth enhancing properties of Sitka spruce (Picea sitchensis Bong.) wood ash were contrasted with the potential toxic action, using common duckweed (Lemna minor L.) as a model test species. The growth of L. minor exposed to wood bottom and fly ash solids and corresponding leachates was assessed in ultra-oligotrophic and eutrophic media. Ash solids and leachates were also tested as neutralized preparations. Suspended ash solids promoted L. minor growth up to concentrations of 2.5-5g/L. Leachates promoted growth up to 10g ash equivalents per litre, but for bottom ash only. Beneficial effects of wood ash were most pronounced on ultra-oligotrophic medium. However, on such nutrient-deficient medium severe inhibition of L. minor biomass and frond growth was observed at relatively low concentrations of fly ash (EC 50 =14g/L). On standard, eutrophic medium, higher concentrations of fly ash (EC 50 =21g/L), or neutralized fly ash (EC 50 =37g/L) were required to impede growth. Bottom ash, or neutralized bottom ash retarded growth at concentrations of 51g/L and 74g/L (EC 50 ), respectively, in eutrophic medium. It appears that phytotoxicity is due to the elemental composition of the ash, its alkaline character, and possible interactions between these two properties. Growth promotion was due to the substantial content of plant nutrients. This study underlines the importance of the receiving environment (nutrient status and pH) in determining the balance between toxicity and growth promotion, and shows that the margin between growth promoting and toxicity inducing concentrations can be enlarged through ash neutralization. Copyright © 2017 Elsevier B.V. All rights reserved.

Direct analysis of ultra-trace semiconductor gas by inductively coupled plasma mass spectrometry coupled with gas to particle conversion-gas exchange technique.

PubMed

Ohata, Masaki; Sakurai, Hiromu; Nishiguchi, Kohei; Utani, Keisuke; Günther, Detlef

2015-09-03

An inductively coupled plasma mass spectrometry (ICPMS) coupled with gas to particle conversion-gas exchange technique was applied to the direct analysis of ultra-trace semiconductor gas in ambient air. The ultra-trace semiconductor gases such as arsine (AsH3) and phosphine (PH3) were converted to particles by reaction with ozone (O3) and ammonia (NH3) gases within a gas to particle conversion device (GPD). The converted particles were directly introduced and measured by ICPMS through a gas exchange device (GED), which could penetrate the particles as well as exchange to Ar from either non-reacted gases such as an air or remaining gases of O3 and NH3. The particle size distribution of converted particles was measured by scanning mobility particle sizer (SMPS) and the results supported the elucidation of particle agglomeration between the particle converted from semiconductor gas and the particle of ammonium nitrate (NH4NO3) which was produced as major particle in GPD. Stable time-resolved signals from AsH3 and PH3 in air were obtained by GPD-GED-ICPMS with continuous gas introduction; however, the slightly larger fluctuation, which could be due to the ionization fluctuation of particles in ICP, was observed compared to that of metal carbonyl gas in Ar introduced directly into ICPMS. The linear regression lines were obtained and the limits of detection (LODs) of 1.5 pL L(-1) and 2.4 nL L(-1) for AsH3 and PH3, respectively, were estimated. Since these LODs revealed sufficiently lower values than the measurement concentrations required from semiconductor industry such as 0.5 nL L(-1) and 30 nL L(-1) for AsH3 and PH3, respectively, the GPD-GED-ICPMS could be useful for direct and high sensitive analysis of ultra-trace semiconductor gas in air. Copyright © 2015 Elsevier B.V. All rights reserved.

Application of Iron Oxide as a pH-dependent Indicator for Improving the Nutritional Quality

PubMed Central

2016-01-01

Acid food indicators can be used as pH indicators for evaluating the quality and freshness of fermented products during the full course of distribution. Iron oxide particles are hardly suspended in water, but partially or completely agglomerated. The agglomeration degree of the iron oxide particles depends on the pH. The pH-dependent particle agglomeration or dispersion can be useful for monitoring the acidity of food. The zeta potential of iron oxide showed a decreasing trend as the pH increased from 2 to 8, while the point of zero charge (PZC) was observed around at pH 6.0-7.0. These results suggested that the size of the iron oxide particles was affected by the change in pH levels. As a result, the particle sizes of iron oxide were smaller at lower pH than at neutral pH. In addition, agglomeration of the iron oxide particles increased as the pH increased from 2 to 7. In the time-dependent aggregation test, the average particle size was 730.4 nm and 1,340.3 nm at pH 2 and 7, respectively. These properties of iron oxide particles can be used to develop an ideal acid indicator for food pH and to monitor food quality, besides a colorant or nutrient for nutrition enhancement and sensory promotion in food industry. PMID:27482521

Removal of hazardous metals from MSW fly ash--an evaluation of ash leaching methods.

PubMed

Fedje, Karin Karlfeldt; Ekberg, Christian; Skarnemark, Gunnar; Steenari, Britt-Marie

2010-01-15

Incineration is a commonly applied management method for municipal solid waste (MSW). However, significant amounts of potentially hazardous metal species are present in the resulting ash, and these may be leached into the environment. A common idea for cleaning the ash is to use enhanced leaching with strong mineral acids. However, due to the alkalinity of the ash, large amounts of acid are needed and this is a drawback. Therefore, this work was undertaken in order to investigate some alternative leaching media (EDTA, ammonium nitrate, ammonium chloride and a number of organic acids) and to compare them with the usual mineral acids and water. All leaching methods gave a significant increase in ash specific surface area due to removal of soluble bulk (matrix) compounds, such as CaCO(3) and alkali metal chlorides. The use of mineral acids and EDTA mobilised many elements, especially Cu, Zn and Pb, whereas the organic acids generally were not very effective as leaching agents for metals. Leaching using NH(4)NO(3) was especially effective for the release of Cu. The results show that washing of MSW filter ash with alternative leaching agents is a possible way to remove hazardous metals from MSW fly ash.

Ash aggregation enhanced by deposition and redistribution of salt on the surface of volcanic ash in eruption plumes.

PubMed

Mueller, Sebastian B; Ayris, Paul M; Wadsworth, Fabian B; Kueppers, Ulrich; Casas, Ana S; Delmelle, Pierre; Taddeucci, Jacopo; Jacob, Michael; Dingwell, Donald B

2017-03-31

Interactions with volcanic gases in eruption plumes produce soluble salt deposits on the surface of volcanic ash. While it has been postulated that saturation-driven precipitation of salts following the dissolution of ash surfaces by condensed acidic liquids is a primary mechanism of salt formation during an eruption, it is only recently that this mechanism has been subjected to detailed study. Here we spray water and HCl droplets into a suspension of salt-doped synthetic glass or volcanic ash particles, and produce aggregates. Deposition of acidic liquid droplets on ash particles promotes dissolution of existing salts and leaches cations from the underlying material surface. The flow of liquid, due to capillary forces, will be directed to particle-particle contact points where subsequent precipitation of salts will cement the aggregate. Our data suggest that volcanically-relevant loads of surface salts can be produced by acid condensation in eruptive settings. Several minor and trace elements mobilised by surface dissolution are biologically relevant; geographic areas with aggregation-mediated ash fallout could be "hotspots" for the post-deposition release of these elements. The role of liquids in re-distributing surface salts and cementing ash aggregates also offers further insight into the mechanisms which preserve well-structured aggregates in some ash deposits.

Ash aggregation enhanced by deposition and redistribution of salt on the surface of volcanic ash in eruption plumes

PubMed Central

Mueller, Sebastian B.; Ayris, Paul M.; Wadsworth, Fabian B.; Kueppers, Ulrich; Casas, Ana S.; Delmelle, Pierre; Taddeucci, Jacopo; Jacob, Michael; Dingwell, Donald B.

2017-01-01

Interactions with volcanic gases in eruption plumes produce soluble salt deposits on the surface of volcanic ash. While it has been postulated that saturation-driven precipitation of salts following the dissolution of ash surfaces by condensed acidic liquids is a primary mechanism of salt formation during an eruption, it is only recently that this mechanism has been subjected to detailed study. Here we spray water and HCl droplets into a suspension of salt-doped synthetic glass or volcanic ash particles, and produce aggregates. Deposition of acidic liquid droplets on ash particles promotes dissolution of existing salts and leaches cations from the underlying material surface. The flow of liquid, due to capillary forces, will be directed to particle-particle contact points where subsequent precipitation of salts will cement the aggregate. Our data suggest that volcanically-relevant loads of surface salts can be produced by acid condensation in eruptive settings. Several minor and trace elements mobilised by surface dissolution are biologically relevant; geographic areas with aggregation-mediated ash fallout could be “hotspots” for the post-deposition release of these elements. The role of liquids in re-distributing surface salts and cementing ash aggregates also offers further insight into the mechanisms which preserve well-structured aggregates in some ash deposits. PMID:28361966

Comparing Two Independent Satellite-Based Algorithms for Detecting and Tracking Ash Clouds by Using SEVIRI Sensor

PubMed Central

Cooke, Michael C.; Filizzola, Carolina

2018-01-01

The Eyjafjallajökull (Iceland) volcanic eruption of April–May 2010 caused unprecedented air-traffic disruption in Northern Europe, revealing some important weaknesses of current operational ash-monitoring and forecasting systems and encouraging the improvement of methods and procedures for supporting the activities of Volcanic Ash Advisory Centers (VAACs) better. In this work, we compare two established satellite-based algorithms for ash detection, namely RSTASH and the operational London VAAC method, both exploiting sensor data of the spinning enhanced visible and infrared imager (SEVIRI). We analyze similarities and differences in the identification of ash clouds during the different phases of the Eyjafjallajökull eruption. The work reveals, in some cases, a certain complementary behavior of the two techniques, whose combination might improve the identification of ash-affected areas in specific conditions. This is indicated by the quantitative comparison of the merged SEVIRI ash product, achieved integrating outputs of the RSTASH and London VAAC methods, with independent atmospheric infrared sounder (AIRS) DDA (dust-detection algorithm) observations. PMID:29382058

Raman properties of gold nanoparticle-decorated individual carbon nanotubes

NASA Astrophysics Data System (ADS)

Assmus, Tilman; Balasubramanian, Kannan; Burghard, Marko; Kern, Klaus; Scolari, Matteo; Fu, Nan; Myalitsin, Anton; Mews, Alf

2007-04-01

Single-wall carbon nanotubes decorated by gold nanoparticles with sizes of a few tens of nanometers were investigated by confocal Raman microscopy. It was found that individual nanoparticles impart a sizable Raman enhancement exceeding one order of magnitude, without appreciably interfering with polarization dependent Raman measurements. By contrast, cavity effects within small nanoparticle agglomerates resulted in a 20-fold stronger enhancement and significant distortions of the polarization characteristic.

Enhancement of mercury capture by the simultaneous addition of hydrogen bromide (HBr) and fly ashes in a slipstream facility.

PubMed

Cao, Yan; Wang, Quan-Hai; Li, Jun; Cheng, Jen-Chieh; Chan, Chia-Chun; Cohron, Marten; Pan, Wei-Ping

2009-04-15

Low halogen content in tested Powder River Basin (PRB) coals and low loss of ignition content (LOI) in PRB-derived fly ash were likely responsible for higher elemental mercury content (averaging about 75%) in the flue gas and also lower mercury capture efficiency by electrostatic precipitator (ESP) and wet-FGD. To develop a cost-effective approach to mercury capture in a full-scale coal-fired utility boiler burning PRB coal, experiments were conducted adding hydrogen bromide (HBr) or simultaneously adding HBr and selected fly ashes in a slipstream reactor (0.152 x 0.152 m) under real flue gas conditions. The residence time of the flue gas inside the reactorwas about 1.4 s. The average temperature of the slipstream reactor was controlled at about 155 degrees C. Tests were organized into two phases. In Phase 1, only HBr was added to the slipstream reactor, and in Phase 2, HBr and selected fly ash were added simultaneously. HBr injection was effective (>90%) for mercury oxidation at a low temperature (155 degrees C) with an HBr addition concentration of about 4 ppm in the flue gas. Additionally, injected HBr enhanced mercury capture by PRB fly ash in the low-temperature range. The mercury capture efficiency, attesting conditions of the slipstream reactor, reached about 50% at an HBr injection concentration of 4 ppm in the flue gas. Compared to only the addition of HBr, simultaneously adding bituminous-derived fly ash in a minimum amount (30 lb/MMacf), together with HBr injection at 4 ppm, could increase mercury capture efficiency by 30%. Injection of lignite-derived fly ash at 30 lb/MMacf could achieve even higher mercury removal efficiency (an additional 35% mercury capture efficiency compared to HBr addition alone).

Formulation Development of Spherical Crystal Agglomerates of Itraconazole for Preparation of Directly Compressible Tablets with Enhanced Bioavailability.

PubMed

Fadke, Janki; Desai, Jagruti; Thakkar, Hetal

2015-12-01

The objective of the present work was to formulate tablet dosage form of itraconazole with enhanced bioavailability. Spherical crystal agglomerates (SCA) of itraconazole prepared by quasi emulsification solvent diffusion method using Soluplus and polyethylene glycol 4000 (PEG 4000) showed increased solubility (540 μg/ml) in 0.1 N hydrochloric acid as compared to pure drug (12 μg/ml). A Fourier transform infrared (FTIR) study indicated compatibility of drug with the excipients. The developed SCA were spherical with smooth surface having an average size of 412 μm. The significantly improved micromeritic properties compared to the plain drug suggested its suitability for direct compression. The antifungal activity of itraconazole was retained in the SCA form as evidenced from the results of the disc diffusion method. The optimized SCA formulation could be easily compressed into tablet with desirable characteristics of hardness (5 kg/cm(2)) and disintegration time (6.3 min). The in vitro dissolution studies showed significant difference in the dissolution profiles of pure drug (21%) and SCA formulation (85%) which was even greater than that of marketed preparation (75%). In vivo pharmacokinetic showed significant enhancement in C max and AUC0-t with relative bioavailability of 225%. The SCA formulation seems to be promising for enhancement of oral bioavailability of itraconazole.

A brief review on fly ash and its use in surface engineering

NASA Astrophysics Data System (ADS)

Bhajantri, Vishwanath; Krishna, Prasad; Jambagi, Sudhakar

2018-04-01

Fly ash is a by-product obtained from coal power plants. Over the past two decades, handling this industrial waste has been a great challenge for many developing countries. However, this menace can be used in many industrial applications viz., civil, automobile and aerospace applications. In civil industry, the fly ash has been used in concreate to enhance the porosity that increases the curing time of the concrete. The fly ash has been gaining importance these days as a feedstock material for many thermal spray processes. In automobile sector, the fly ash has been used as a thermal barrier coating in IC engines, whereas in aerospace industry, which demands lighter and stronger materials, the fly ash has been used as a reinforcement material. Hence, so far, fly ash has been used as an either single or a composite feed stock material in thermal spray processes. The fly ash with other materials like alumina, titania and red mud have been deposited using thermal spray processes. These coatings have exhibited higher wear, corrosion and erosion resistance as compared to the uncoated specimens. In this paper, a brief review on fly ash and its use, especially its use as a feed stock in thermal spray coating, is presented. Therefore, the use of fly ash has opened a new frontier of research in thermal spray coating area where economically viable coatings can be produced using industrial waste like fly ash.

Utilization of coal fly ash as a slow-release granular medium for soil improvement.

PubMed

Yoo, Jeong Gun; Jo, Young Min

2003-01-01

This work proposes a new potential application of waste coal fly ash as a K fertilizer support. Fly ash was reacted with KOH to facilitate the impregnation of K as well as to enhance the bonding force. In particular, the applied process resulted in a significant slow-releasing characteristic of fertilizer elements. To examine the effect of K impregnation, a few detailed leaching tests were carried out in terms of process variables such as reaction time and temperature, sintering time and temperature, and KOH concentration. The current experiment presented an optimum preparation condition that is competitive with conventional commercial fertilizers. The manufactured ash fertilizers inhibited release of the K elements. It was also found through the continuous leaching test with pure water that the ash fertilizer had excellent moisture absorbability. However, the effects of some trace elements in fly ash on soil health and crop productivity as well as environmental considerations need to be established with long-term studies.

Agglomerated novel spray-dried lactose-leucine tailored as a carrier to enhance the aerosolization performance of salbutamol sulfate from DPI formulations.

PubMed

Molina, Carlos; Kaialy, Waseem; Chen, Qiao; Commandeur, Daniel; Nokhodchi, Ali

2017-12-19

Spray-drying allows to modify the physicochemical/mechanical properties of particles along with their morphology. In the present study, L -leucine with varying concentrations (0.1, 0.5, 1, 5, and 10% w/v) were incorporated into lactose monohydrate solution for spray-drying to enhance the aerosolization performance of dry powder inhalers containing spray-dried lactose-leucine and salbutamol sulfate. The prepared spray-dried lactose-leucine carriers were analyzed using laser diffraction (particle size), differential scanning calorimetry (thermal behavior), scanning electron microscopy (morphology), powder X-ray diffraction (crystallinity), Fourier transform infrared spectroscopy (interaction at molecular level), and in vitro aerosolization performance (deposition). The results showed that the efficacy of salbutamol sulfate's aerosolization performance was, in part, due to the introduction of L -leucine in the carrier, prior to being spray-dried, accounting for an increase in the fine particle fraction (FPF) of salbutamol sulfate from spray-dried lactose-leucine (0.5% leucine) in comparison to all other carriers. It was shown that all of the spray-dried carriers were spherical in their morphology with some agglomerates and contained a mixture of amorphous, α-lactose, and β-lactose. It was also interesting to note that spray-dried lactose-leucine particles were agglomerated during the spray-drying process to make coarse particles (volume mean diameter of 79 to 87 μm) suitable as a carrier in DPI formulations.

Impact of agglomeration on the relaxometric properties of paramagnetic ultra-small gadolinium oxide nanoparticles

NASA Astrophysics Data System (ADS)

Faucher, Luc; Gossuin, Yves; Hocq, Aline; Fortin, Marc-André

2011-07-01

Ultra-small gadolinium oxide nanoparticles (US-Gd2O3) are used to provide 'positive' contrast effects in magnetic resonance imaging (MRI), and are being considered for molecular and cellular imaging applications. However, these nanoparticles can aggregate over time in aqueous medium, as well as when internalized into cells. This study is aimed at measuring in vitro, in aqueous medium, the impact of aggregation on the relaxometric properties of paramagnetic US-Gd2O3 particles. First, the nanoparticle core size as well as aggregation behaviour was assessed by HRTEM. DLS (hydrodynamic diameter) was used to measure the hydrodynamic diameter of nanoparticles and nanoaggregates. The relaxometric properties were measured by NMRD profiling, as well as with 1H NMR relaxometers. Then, the positive contrast enhancement effect was assessed by using magnetic resonance scanners (at 1.5 and 7 T). At every magnetic field, the longitudinal relaxivity (r1) decreased upon agglomeration, while remaining high enough to provide positive contrast. On the other hand, the transverse relaxivity (r2) slightly decreased at 0.47 and 1.41 T, but it was enhanced at higher fields (7 and 11.7 T) upon agglomeration. All NMRD profiles revealed a characteristic relaxivity peak in the range 60-100 MHz, suggesting the possibility to use US-Gd2O3 as an efficient 'positive-T1' contrast agent at clinical magnetic fields (1-3 T), in spite of aggregation.

Synthesis of Single Crystalline ZnO Nanoparticles by Salt-Assisted Spray Pyrolysis

NASA Astrophysics Data System (ADS)

Panatarani, Camellia; Lenggoro, I. Wuled; Okuyama, Kikuo

2003-04-01

LiNO3 was used as a shield in the preparation of single crystalline ZnO particles by a spray pyrolysis process in order to prevent agglomeration and enhance the crystallinity of the ZnO. LiNO3 was added to a precursor solution of zinc acetate dihydrate prior to its atomization by means of an ultrasonic transducer. Agglomerate-free particles having a mean particle size of 26 nm were successfully obtained after washing the product. X-ray diffractometry, field-emission scanning electron micrograph and transmission electron micrograph data indicate that the size and morphology of ZnO were strongly influenced by the operating temperature used and the residence time of the particle in the reactor.

A model for tropical-extratropical transport of volcanic ash in the lower stratosphere

NASA Technical Reports Server (NTRS)

Rietmeijer, Frans J. M.

1993-01-01

Large nonspherical volcanic ash particles up to 30 micrometer in size were collected between 17-19 km altitude over the Northern Hemisphere at high latitudes between October 1988 and April 1990. These particles may be derived from minor Plinian eruptions in the tropics rather than from localized volcanic activity close to the collection region. Ash particles were injected into the lower equatorial stratosphere where they entered a regime of efficient transport just above the tropopause from the tropical region towards the northern extratropical region. Transport is enhanced by stable autorotation that generates a sufficient lift force to loft nonspherical ash with a rough surface during transport, and by the gradually decreasing altitude of the tropopause from the tropics to the polar regions.

Characterization of Rare Earth Element Minerals in Coal Utilization Byproducts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Montross, Scott N.; Verba, Circe A.; Collins, Keith

The United States currently produces over 100 million tons of coal utilization byproducts (CUB) per year in the form of fly ash, bottom ash, slag, and flue gas (American Coal Ash Association (ACCA), 2015). But this “waste material” also contains potentially useful levels of rare earth elements (REE). Rare earth elements are crucial for many existing and emerging technologies, but the U.S. lacks a domestic, sustainable REE source. Our project explored the possibility of developing a supply of REEs for U.S. technologies by extracting REEs from CUBs. This work offers the potential to reduce our dependence on other countries formore » supply of these critical elements (NETL, REE 2016 Project Portfolio). Geologic and diagenetic history, industrial preparation methods, and the specific combustion process all play major roles in the composition of CUB. During combustion, inorganic mineral phases of coal particles are fluidized at temperatures higher than 1400oC, so inorganic mineral materials are oxidized, fused, disintegrated, or agglomerated into larger spherical and amorphous (non-crystalline) particles. The original mineralogy of the coal-containing rock and heating/cooling of the material significantly affects the composition and morphology of the particles in the combustion byproduct (Kutchko and Kim, 2006). Thus, different types of coal/refuse/ash must be characterized to better understand mineral evolution during the combustion process. Our research focused on developing a working model to address how REE minerals behave during the combustion process: this research should help determine the most effective engineering methods for extracting REEs from CUBs. We used multimodal imaging and image processing techniques to characterize six rock and ash samples from different coal power plants with respect to morphology, grain size, presence of mineral phases, and elemental composition. The results of these characterization activities provided thresholds for realizing the occurrence of REE mineral phases in CUB and allowed us to calculate structural and volumetric estimates of REE. Collectively, the rock and coal ash samples contained minerals such as quartz, kaolinite, muscovite/illite, iron oxide (as hematite or magnetite), mullite, and clinochlore. Trace minerals included pyrite, zircon, siderite, rutile, diopside, foresterite, gypsum, and barite. We identified REE phosphate minerals monazite (Ce,La,Nd,Th)(PO 4,SiO 4), xenotime (YPO 4,SiO 4), and apatite (Ca 5(PO 4) 3(F,Cl,OH) via SEM and electron microprobe analysis: these materials generally occurred as 1-10 μm-long crystals in the rock and ash samples. As has been shown in other studies, amorphous material-aluminosilicate glass or iron oxyhydroxide-are the major components of coal fly and bottom ash. Trace amounts of amorphous calcium oxide and mixed element (e.g., Al-Si-Ca-Fe) slag are also present. Quartz, mullite, hematite, and magnetite are the crystalline phases present. We found that REEs are present as monomineralic grains dispersed within the ash, as well as fused to or encapsulated by amorphous aluminosilicate glass particles. Monazite and xenotime have relatively high melting points (>1800 °C) compared to typical combustion temperatures; our observations indicate that the REE-phosphates, which presumably contribute a large percentage of REE to the bulk ash REE pool, as measured by mass spectroscopy, are largely unaltered by the combustion. Our study shows that conventional coal combustion processes sequester REE minerals into aluminosilicate glass phases, which presents a new engineering challenge for extracting REE from coal ash. The characterization work summarized in this report provides a semi-quantitative assessments of REE in coal-containing rock and CUB. The data we obtained from 2- and 3-D imaging, elemental mapping, volumetric estimates, and advanced high-resolution pixel classification successfully identified the different mineral phases present in CUB. Further, our characterization results can guide techniques for extracting REEs from CUB, or other geologic and engineered materials. Whilst, interpretations will inform future REE separation and extraction techniques and technologies practical for commercial utilization of combustion byproducts generated by power plants.« less

Merging two waste streams, wood ash and biowaste, results in improved composting process and end products.

PubMed

Fernández-Delgado Juárez, M; Gómez-Brandón, M; Insam, H

2015-04-01

A trial was carried out to evaluate the influence of wood ash admixture on biowaste composting. The aim was to find the optimal dosage of ash addition to enhance the composting process without endangering the final compost characteristics and use. Six treatments including an unamended control (K0) and composts with additions of 3% (K3), 6% (K6), 9% (K9), 12% (K12) and 15% (K15) of wood ash (w/w) were studied. The composting process was monitored in situ for 49days, by measuring temperature, CO2, O2, and CH4 in the piles and pH, electric conductivity (EC), and inorganic N in the laboratory. At the end of the process, the products were tested for Reifegrad (maturity), toxicity and quality. The addition of up to 15% of wood ash to biowaste did not negatively affect the composting process, and the initial differences found between both the low and high ash-treated composts were attenuated with the ongoing process development. Nevertheless, and mainly due to Cd level, composts with higher ash amendment did not comply with the highest quality standards established by the Austrian Compost Ordinance. The failure of obtaining class A+ quality after ash amendment emphasizes the need for a rigid quality selection of (bottom) ashes and thus reducing environmental risks related to high pollutant loads originating from the ashes. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of Mass Proportion of Municipal Solid Waste Incinerator Bottom Ash Layer to Municipal Solid Waste Layer on the Cu and Zn Discharge from Landfill.

PubMed

Kong, Qingna; Yao, Jun; Qiu, Zhanhong; Shen, Dongsheng

2016-01-01

Municipal solid waste incinerator (MSWI) bottom ash is often used as the protection layer for the geomembrane and intermediate layer in the landfill. In this study, three sets of simulated landfills with different mass proportion of MSWI bottom ash layer to municipal solid waste (MSW) layer were operated. Cu and Zn concentrations in the leachates and MSW were monitored to investigate the effect of MSWI bottom ash layer on the Cu and Zn discharge from the landfill. The results showed that the Zn discharge was dependent on the mass proportion of MSWI bottom ash layer. The pH of landfill was not notably increased when the mass proportion of MSWI bottom ash layer to MSW layer was 1 : 9, resulting in the enhancement of the Zn discharge. However, Zn discharge was mitigated when the mass proportion was 2 : 8, as the pH of landfill was notably promoted. The discharge of Cu was not dependent on the mass proportion, due to the great affinity of Cu to organic matter. Moreover, Cu and Zn contents of the sub-MSW layer increased due to the MSWI bottom ash layer. Therefore, the MSWI bottom ash layer can increase the potential environmental threat of the landfill.

Improving the de-agglomeration and dissolution of a poorly water soluble drug by decreasing the agglomerate strength of the cohesive powder.

PubMed

Allahham, Ayman; Stewart, Peter J; Das, Shyamal C

2013-11-30

Influence of ternary, poorly water-soluble components on the agglomerate strength of cohesive indomethacin mixtures during dissolution was studied to explore the relationship between agglomerate strength and extent of de-agglomeration and dissolution of indomethacin (Ind). Dissolution profiles of Ind from 20% Ind-lactose binary mixtures, and ternary mixtures containing additional dibasic calcium phosphate (1% or 10%; DCP), calcium sulphate (10%) and talc (10%) were determined. Agglomerate strength distributions were estimated by Monte Carlo simulation of particle size, work of cohesion and packing fraction distributions. The agglomerate strength of Ind decreased from 1.19 MPa for the binary Ind mixture to 0.84 MPa for 1DCP:20Ind mixture and to 0.42 MPa for 1DCP:2Ind mixture. Both extent of de-agglomeration, demonstrated by the concentration of the dispersed indomethacin distribution, and extent of dispersion, demonstrated by the particle size of the dispersed indomethacin, were in descending order of 1DCP:2Ind>1DCP:20Ind>binary Ind. The addition of calcium sulphate dihydrate and talc also reduced the agglomerate strength and improved de-agglomeration and dispersion of indomethacin. While not definitively causal, the improved de-agglomeration and dispersion of a poorly water soluble drug by poorly water soluble components was related to the agglomerate strength of the cohesive matrix during dissolution. Copyright © 2013 Elsevier B.V. All rights reserved.

In vitro dosimetry of agglomerates

NASA Astrophysics Data System (ADS)

Hirsch, V.; Kinnear, C.; Rodriguez-Lorenzo, L.; Monnier, C. A.; Rothen-Rutishauser, B.; Balog, S.; Petri-Fink, A.

2014-06-01

Agglomeration of nanoparticles in biological fluids is a pervasive phenomenon that leads to difficulty in the interpretation of results from in vitro exposure, primarily due to differing particokinetics of agglomerates to nanoparticles. Therefore, well-defined small agglomerates were designed that possessed different particokinetic profiles, and their cellular uptake was compared to a computational model of dosimetry. The approach used here paves the way for a better understanding of the impact of agglomeration on the nanoparticle-cell interaction.Agglomeration of nanoparticles in biological fluids is a pervasive phenomenon that leads to difficulty in the interpretation of results from in vitro exposure, primarily due to differing particokinetics of agglomerates to nanoparticles. Therefore, well-defined small agglomerates were designed that possessed different particokinetic profiles, and their cellular uptake was compared to a computational model of dosimetry. The approach used here paves the way for a better understanding of the impact of agglomeration on the nanoparticle-cell interaction. Electronic supplementary information (ESI) available: ITC data for tiopronin/Au-NP interactions, agglomeration kinetics at different pHs for tiopronin-coated Au-NPs, UV-Vis spectra in water, PBS and DMEM and temporal correlation functions for single Au-NPs and corresponding agglomerates, calculation of diffusion and sedimentation parameters, modelling of relative cell uptake based on the ISDD model and cytotoxicity of single Au-NPs and their agglomerates, and synthesis and cell uptake of large spherical Au-NPs. See DOI: 10.1039/c4nr00460d

The effect of cyclodextrin on both the agglomeration and the in vitro characteristics of drug loaded and targeted silica nanoparticles

NASA Astrophysics Data System (ADS)

Khattabi, Areen M.; Alqdeimat, Diala A.

2018-02-01

One of the problems in the use of nanoparticles (NPs) as carriers in drug delivery systems is their agglomeration which mainly appears due to their high surface energy. This results in formation of NPs with different sizes leading to differences in their distribution and bioavailability. The surface coating of NPs with certain compounds can be used to prevent or minimize this problem. In this study, the effect of cyclodextrin (CD) on the agglomeration state and hence on the in vitro characteristics of drug loaded and targeted silica NPs was investigated. A sample of NPs was loaded with anticancer agents, then modified with a long polymer, carboxymethyl-β-cyclodextrin (CM-β-CD) and folic acid (FA), respectively. Another sample was modified similarly but without CD. The surface modification was characterized using fourier transform infrared spectroscopy (FT-IR). The polydispersity (PD) was measured using dynamic light scattering (DLS) and was found to be smaller for CD modified NPs. The results of the in vitro drug release showed that the release rate from both samples exhibited similar pattern for the first 5 hours, however the rate was faster from CD modified NPs after 24 hours. The in vitro cell viability assay confirmed that CD modified NPs were about 30% more toxic to HeLa cells. These findings suggest that CD has a clear effect in minimizing the agglomeration of such modified silica NPs, accelerating their drug release rate and enhancing their targeting effect.

Enhanced Ethanol Production from De-Ashed Paper Sludge by Simultaneous Saccharification and Fermentation and Simultaneous Saccharification and Co-Fermentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, L.; Wang, W.; Pallapolu, V. R.

2011-11-01

A previous study demonstrated that paper sludges with high ash contents can be converted to ethanol by simultaneous saccharification and fermentation (SSF) or simultaneous saccharification and co-fermentation (SSCF). High ash content in the sludge, however, limited solid loading in the bioreactor, causing low product concentration. To overcome this problem, sludges were de-ashed before SSF and SSCF. Low ash content in sludges also increased the ethanol yield to the extent that the enzyme dosage required to achieve 70% yield in the fermentation process was reduced by 30%. High solid loading in SSF and SSCF decreased the ethanol yield. High agitation andmore » de-ashing of the sludges were able to restore the part of the yield loss caused by high solid loading. Substitution of the laboratory fermentation medium (peptone and yeast extract) with corn steep liquor did not bring about any adverse effects in the fermentation. Fed-batch operation of the SSCF and SSF using low-ash content sludges was effective in raising the ethanol concentration, achieving 47.8 g/L and 60.0 g/L, respectively.« less

Silica Fume Functionalized With Amine-Based Additives as a Modifier to Enhance Asphalt Resistance to Oxidation

NASA Astrophysics Data System (ADS)

Abutalib, Nader Turki

This dissertation investigates the practical feasibility of functionalizing silica fume particles with the amine groups in Bio-binder and pure APTES chemical to disperse silica fume in asphalt binder matrix to produce silica-fume-modified binder (SFMB). Dispersed silica fume was then introduced to asphalt to reduce oxidative aging. It has been widely reported that asphalt binder oxidation is one of the phenomena that reduces the service life of asphalt pavement by negatively affecting its rheological properties. This in turn can lead to a more brittle pavement, which is more prone to cracks due to thermal stress and traffic loading. It has been shown that the introduction of 4% silica fume to asphalt can reduce asphalt oxidative aging. However, the challenge with a higher percentage of silica fume was found to be the agglomeration of nano- particles to form micro-size clusters, which can reduce the effectiveness of silica fume while making asphalt binder more susceptible to shear. Therefore, this dissertation studies the effectiveness of functionalizing the SFMB to reduce asphalt oxidative aging while alleviating the agglomeration effect. To do so, various percentages of bio-binder (BB) and bio-char (BC) were introduced to SFMB, and the rheological properties and high-temperature performance of each specimen were evaluated by measuring the rotational viscosity and complex shear modulus before and after oxidative aging. It is hypothesized that fine-graded BC and BB with nano- to micro-level particles can be used to reduce asphalt oxidation and create a new generation of low- agglomeration SFMB with higher resistance to oxidative aging. To further study the effects of functionalization on dispersion of silica fume, silica fume particles were produced with different functional groups: amine (APTES) groups and phosphonate (THPMP) groups. Agglomeration studies using a scanning electron microscope and zeta potential analysis indicate that modifying asphalt binder with amine-modified silica fume particles can reduce the agglomeration of the silica fume particles. The performance characteristics of functionalized silica fume particles and non-functionalized silica fume particles are compared with those of base asphalt. The following research hypotheses were investigated: 1) Functionalized and well-dispersed silica fume will enhance asphalt's aging resistance. 2) The amine groups in functionalizing agent interact with silica fume particles and promote their dispersion. To test these hypotheses, a rotational viscometer was used to study the effect of functionalized-silica-fume-modified binder on the high-temperature properties of the asphalt binder. Fourier transform infrared spectroscopy analysis was used to determine the chemical compounds of the amine-group silica-fume- modified binder matrix. Scanning electron microscopy was used to observe the surface morphology and analyze the microstructure characteristics of materials. The positive effect of amine groups on the rheological properties of SFMB could be attributed to the high surface area of the silica fume and its granular particles with high polarity, factors that could improve the blending properties of the bio-modified silica fume and result in a uniformly distributed silica- fume-modified matrix with enhanced oxidative aging resistance. Surface adsorption of amines on silica fume particles helps promote repulsive forces between them to enhance dispersion.

Fuel agglomerates and method of agglomeration

DOEpatents

Wen, Wu-Wey

1986-01-01

Solid fuel agglomerates are prepared of particulate coal or other carbonaceous material with a binder having a high humic acid or humate salt content. The humic acid is extracted from oxidized carbonaceous material with a mild aqueous alkali solution of, for instance, ammonia. The particulate material is blended with the extract which serves as the binder for the agglomerates. The water-resistant agglomerates are formed such as by pelletizing, followed by drying to remove moisture and solidify the humic acid binder throughout the agglomerate.

Trends in the Rare Earth Element Content of U.S.-Based Coal Combustion Fly Ashes.

PubMed

Taggart, Ross K; Hower, James C; Dwyer, Gary S; Hsu-Kim, Heileen

2016-06-07

Rare earth elements (REEs) are critical and strategic materials in the defense, energy, electronics, and automotive industries. The reclamation of REEs from coal combustion fly ash has been proposed as a way to supplement REE mining. However, the typical REE contents in coal fly ash, particularly in the United States, have not been comprehensively documented or compared among the major types of coal feedstocks that determine fly ash composition. The objective of this study was to characterize a broad selection of U.S. fly ashes of varied geological origin in order to rank their potential for REE recovery. The total and nitric acid-extractable REE content for more than 100 ash samples were correlated with characteristics such as the major element content and coal basin to elucidate trends in REE enrichment. Average total REE content (defined as the sum of the lanthanides, yttrium, and scandium) for ashes derived from Appalachian sources was 591 mg kg(-1) and significantly greater than in ashes from Illinois and Powder River basin coals (403 and 337 mg kg(-1), respectively). The fraction of critical REEs (Nd, Eu, Tb, Dy, Y, and Er) in the fly ashes was 34-38% of the total and considerably higher than in conventional ores (typically less than 15%). Powder River Basin ashes had the highest extractable REE content, with 70% of the total REE recovered by heated nitric acid digestion. This is likely due to the higher calcium content of Powder River Basin ashes, which enhances their solubility in nitric acid. Sc, Nd, and Dy were the major contributors to the total REE value in fly ash, based on their contents and recent market prices. Overall, this study shows that coal fly ash production could provide a substantial domestic supply of REEs, but the feasibility of recovery depends on the development of extraction technologies that could be tailored to the major mineral content and origins of the feed coal for the ash.

Aluminum agglomeration involving the second mergence of agglomerates on the solid propellants burning surface: Experiments and modeling

NASA Astrophysics Data System (ADS)

Ao, Wen; Liu, Xin; Rezaiguia, Hichem; Liu, Huan; Wang, Zhixin; Liu, Peijin

2017-07-01

The agglomeration of aluminum particles usually occurs on the burning surface of aluminized composite propellants. It leads to low propellant combustion efficiency and high two-phase flow losses. To reach a thorough understanding of aluminum agglomeration behaviors, agglomeration processes, and particles size distribution of Al/AP/RDX/GAP propellants were studied by using a cinephotomicrography experimental technique, under 5 MPa. Accumulation, aggregation, and agglomeration phenomena of aluminum particles have been inspected, as well as the flame asymmetry of burning agglomerates. Results reveals that the dependency of the mean and the maximum agglomeration diameter to the burning rate and the virgin aluminum size have the same trend. A second-time mergence of multiple agglomerates on the burning surface is unveiled. Two typical modes of second mergence are concluded, based upon vertical and level movement of agglomerates, respectively. The latter mode is found to be dominant and sometimes a combination of the two modes may occur. A new model of aluminum agglomeration on the burning surface of composite propellants is derived to predict the particulates size distribution with a low computational amount. The basic idea is inspired from the well-known pocket models. The pocket size of the region formed by adjacent AP particles is obtained through scanning electron microscopy of the propellant cross-section coupled to an image processing method. The second mergence mechanism, as well as the effect of the burning rate on the agglomeration processes, are included in the present model. The mergence of two agglomerates is prescribed to occur only if their separation distance is less than a critical value. The agglomerates size distribution resulting from this original model match reasonably with the experimental data. Moreover, the present model gives superior results for mean agglomeration diameter compared to common empirical and pocket models. The average prediction error is lower than 5% for the four propellants tested. Results of this study are expected to provide better insight and enrich in the theoretical frame of aluminum agglomeration.

Imaginary refractive index and other microphysical properties of volcanic ash, Sarahan dust, and other mineral aerosols

NASA Astrophysics Data System (ADS)

Rocha Lima, A.; Martins, J.; Krotkov, N. A.; Artaxo, P.; Todd, M.; Ben Ami, Y.; Dolgos, G.; Espinosa, R.

2013-12-01

Aerosol properties are essential to support remote sensing measurements, atmospheric circulation and climate models. This research aims to improve the understanding of the optical and microphysical properties of different types of aerosols particles. Samples of volcanic ash, Saharan dust and other mineral aerosols particles were analyzed by different techniques. Ground samples were sieved down to 45um, de-agglomerated and resuspended in the laboratory using a Fluidized Bed Aerosol Generator (FBAG). Particles were collected on Nuclepore filters into PM10, PM2.5, or PM1.0. and analyzed by different techniques, such as Scanning Electron Microscopy (SEM) for determination of size distribution and shape, spectral reflectance for determination of the optical absorption properties as a function of the wavelength, material density, and X-Ray fluorescence for the elemental composition. The spectral imaginary part of refractive index from the UV to the short wave infrared (SWIR) wavelength was derived empirically from the measurements of the spectral mass absorption coefficient, size distribution and density of the material. Some selected samples were also analyzed with the Polarized Imaging Nephelometer (PI-Neph) instrument for the characterization of the aerosol polarized phase function. This work compares results of the spectral refractive index of different materials obtained by our methodology with those available in the literature. In some cases there are significant differences both in magnitude and spectral dependence of the imaginary refractive index. These differences are evaluated and discussed in this work.

The immersion freezing behavior of ash particles from wood and brown coal burning

NASA Astrophysics Data System (ADS)

Grawe, Sarah; Augustin-Bauditz, Stefanie; Hartmann, Susan; Hellner, Lisa; Pettersson, Jan B. C.; Prager, Andrea; Stratmann, Frank; Wex, Heike

2016-11-01

It is generally known that ash particles from coal combustion can trigger ice nucleation when they interact with water vapor and/or supercooled droplets. However, data on the ice nucleation of ash particles from different sources, including both anthropogenic and natural combustion processes, are still scarce. As fossil energy sources still fuel the largest proportion of electric power production worldwide, and biomass burning contributes significantly to the global aerosol loading, further data are needed to better assess the ice nucleating efficiency of ash particles. In the framework of this study, we found that ash particles from brown coal (i.e., lignite) burning are up to 2 orders of magnitude more ice active in the immersion mode below -32 °C than those from wood burning. Fly ash from a coal-fired power plant was shown to be the most efficient at nucleating ice. Furthermore, the influence of various particle generation methods on the freezing behavior was studied. For instance, particles were generated either by dispersion of dry sample material, or by atomization of ash-water suspensions, and then led into the Leipzig Aerosol Cloud Interaction Simulator (LACIS) where the immersion freezing behavior was examined. Whereas the immersion freezing behavior of ashes from wood burning was not affected by the particle generation method, it depended on the type of particle generation for ash from brown coal. It was also found that the common practice of treating prepared suspensions in an ultrasonic bath to avoid aggregation of particles led to an enhanced ice nucleation activity. The findings of this study suggest (a) that ash from brown coal burning may influence immersion freezing in clouds close to the source and (b) that the freezing behavior of ash particles may be altered by a change in sample preparation and/or particle generation.

Effect of industrial and domestic ash from biomass combustion, and spent coffee grounds, on soil fertility and plant growth: experiments at field conditions.

PubMed

Ribeiro, João Peres; Vicente, Estela Domingos; Gomes, Ana Paula; Nunes, Maria Isabel; Alves, Célia; Tarelho, Luís A C

2017-06-01

An experimental study was conducted at field conditions in order to evaluate the effect of application of ash from biomass combustion on some soil fertility characteristics and plant growth. Application of 7.5 Mg ha -1 industrial fly ash (IA), domestic ash (DA), and a 50:50 mix of domestic ash (DA) and spent coffee grounds (SCG) was made in different soil parcels. Lolium perenne seeds were sown and the grown biomass was harvested and quantified after 60 days. Soil samples from each parcel were also collected after that period and characterized. Both soil and grown biomass samples were analyzed for Ca, Mg, Na, K, P, Fe, Mn, Zn, and Al contents. Soil pH was determined before and after amendment. All applications rose significantly soil pH. Domestic ash, whether combined with coffee grounds or not, proved to be efficient at supplying available macronutrients Ca, Mg, K, and P to the soil and also reducing availability of Al (more than industrial ash). However, it inhibited plant growth, even more when combined with spent coffee grounds. As regards to elemental abundance in plant tissue, both domestic ash treatments reduced Ca and enhanced Al contents, unlike industrial ash, which proved less harmful for the load applied in the soil. Hence, it was possible to conclude that application load should be a limiting factor for this management option for the studied materials.

Retrieval of volcanic ash height from satellite-based infrared measurements

NASA Astrophysics Data System (ADS)

Zhu, Lin; Li, Jun; Zhao, Yingying; Gong, He; Li, Wenjie

2017-05-01

A new algorithm for retrieving volcanic ash cloud height from satellite-based measurements is presented. This algorithm, which was developed in preparation for China's next-generation meteorological satellite (FY-4), is based on volcanic ash microphysical property simulation and statistical optimal estimation theory. The MSG satellite's main payload, a 12-channel Spinning Enhanced Visible and Infrared Imager, was used as proxy data to test this new algorithm. A series of eruptions of Iceland's Eyjafjallajökull volcano during April to May 2010 and the Puyehue-Cordón Caulle volcanic complex eruption in the Chilean Andes on 16 June 2011 were selected as two typical cases for evaluating the algorithm under various meteorological backgrounds. Independent volcanic ash simulation training samples and satellite-based Cloud-Aerosol Lidar with Orthogonal Polarization data were used as validation data. It is demonstrated that the statistically based volcanic ash height algorithm is able to rapidly retrieve volcanic ash heights, globally. The retrieved ash heights show comparable accuracy with both independent training data and the lidar measurements, which is consistent with previous studies. However, under complicated background, with multilayers in vertical scale, underlying stratus clouds tend to have detrimental effects on the final retrieval accuracy. This is an unresolved problem, like many other previously published methods using passive satellite sensors. Compared with previous studies, the FY-4 ash height algorithm is independent of simultaneous atmospheric profiles, providing a flexible way to estimate volcanic ash height using passive satellite infrared measurements.

Hazards posed by distal ash transport and sedimentation from extreme volcanic eruptions

NASA Astrophysics Data System (ADS)

Sahagian, D. L.; Proussevitch, A. A.; White, C. M.; Klewicki, J.

2016-12-01

Volcanic ash injected into the upper troposphere and lower stratosphere poses a significant hazard to aviation and human security as a result of extreme, explosive eruptions. These have occurred in the recent geologic past, and are expected to occur again, now that modern society and its infrastructure is far more vulnerable than ever before. Atmospheric transport, dispersion, and sedimentation of Ash particles is controlled by fundamentally different processes than control other particles normally transported in the atmosphere due to their complex internal and external morphology. It is thus necessary to elucidate the fundamental processes of particle-fluid interactions in the upper troposphere and lower stratosphere, where most air traffic resides, and thereby enhance the capability of volcanic ash transport models to predict the ash concentration in distal regions that pose aviation and other hazards. Current Volcanic Ash Transport and Dispersion (VATD) models use simplistic stokes settling velocities for larger ash particles, and treat smaller ash particles (that are a large part of the hazard) merely as passive tracers. By incorporating the dynamics of fine ash particle-atmosphere interactions into existing VATD models provides the foundation for a much more accurate assessment framework applied to the hazard posed by specific future extreme eruptions, and thus dramatically reduce both the risk to air traffic and the cost of airport and flight closures, in addition to human health, water quality, agricultural, infrastructure hazards, as well as ice cap albedo and short term climate impacts.

Enhancement of binding characteristics for production of an agglomerated product

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taulbee, Darrell; Hodgen, Robert

A method is provided for preparing a product from a precursor material. The method includes the steps of (a) mixing a particulate material and a binder to form a precursor material and (b) irradiating that precursor material with microwave radiation so as to activate the binder and form the product.

Impact of anthropogenic heat release on regional climate in three vast urban agglomerations in China

NASA Astrophysics Data System (ADS)

Feng, Jinming; Wang, Jun; Yan, Zhongwei

2014-03-01

We simulated the impact of anthropogenic heat release (AHR) on the regional climate in three vast city agglomerations in China using the Weather Research and Forecasting model with nested high-resolution modeling. Based on energy consumption and high-quality land use data, we designed two scenarios to represent no-AHR and current-AHR conditions. By comparing the results of the two numerical experiments, changes of surface air temperature and precipitation due to AHR were quantified and analyzed. We concluded that AHR increases the temperature in these urbanized areas by about 0.5°C—1°C, and this increase is more pronounced in winter than in other seasons. The inclusion of AHR enhances the convergence of water vapor over urbanized areas. Together with the warming of the lower troposphere and the enhancement of ascending motions caused by AHR, the average convective available potential energy in urbanized areas is increased. Rainfall amounts in summer over urbanized areas are likely to increase and regional precipitation patterns to be altered to some extent.

Enhancement of deuterium retention in damaged tungsten by plasma-induced defect clustering

NASA Astrophysics Data System (ADS)

Jin, Younggil; Roh, Ki-Baek; Sheen, Mi-Hyang; Kim, Nam-Kyun; Song, Jaemin; Kim, Young-Woon; Kim, Gon-Ho

2017-12-01

The enhancement of deuterium retention was investigated for tungsten in the presence of both 2.8 MeV self-ion induced cascade damage and fuel hydrogen isotope plasma. Vacancy clustering in cascade damaged polycrystalline tungsten occurred due to deuterium irradiation and was observed near the grain boundary by using all-step transmission electron microscopy analysis. Analysis of the highest desorption temperature peak using thermal desorption spectroscopy supports reasonable evidence of defect clustering in the damaged polycrystalline tungsten. The defect clustering was neither observed on the damaged polycrystalline tungsten without deuterium irradiation nor on the damaged single-crystalline tungsten with deuterium irradiation. This result implies the synergetic role of deuterium and grain boundary on defect clustering. This study proposes a path for the defect transform from point defect to defect cluster, by the agglomeration between irradiated deuterium and cascade damage-induced defect. This agglomeration may induce more severe damage on the tungsten divertor at which the high fuel hydrogen ions, fast neutrons, and self-ions are irradiated simultaneously and it would increase the in-vessel tritium inventory.

Pt based PEMFC catalysts prepared from colloidal particle suspensions--a toolbox for model studies.

PubMed

Speder, Jozsef; Altmann, Lena; Roefzaad, Melanie; Bäumer, Marcus; Kirkensgaard, Jacob J K; Mortensen, Kell; Arenz, Matthias

2013-03-14

A colloidal synthesis approach is presented that allows systematic studies of the properties of supported proton exchange membrane fuel cell (PEMFC) catalysts. The applied synthesis route is based on the preparation of monodisperse nanoparticles in the absence of strong binding organic stabilizing agents. No temperature post-treatment of the catalyst is required rendering the synthesis route ideally suitable for comparative studies. We report work concerning a series of catalysts based on the same colloidal Pt nanoparticle (NP) suspension, but with different high surface area (HSA) carbon supports. It is shown that for the prepared catalysts the carbon support has no catalytic co-function, but carbon pre-treatment leads to enhanced sticking of the Pt NPs on the support. An unwanted side effect, however, is NP agglomeration during synthesis. By contrast, enhanced NP sticking without agglomeration can be accomplished by the addition of an ionomer to the NP suspension. The catalytic activity of the prepared catalysts for the oxygen reduction reaction is comparable to industrial catalysts and no influence of the particle size is found in the range of 2-5 nm.

Incorporation of the Fe3O4 and SiO2 nanoparticles in epoxy-modified silicone resin as the coating for soft magnetic composites with enhanced performance

NASA Astrophysics Data System (ADS)

Luo, Dahao; Wu, Chen; Yan, Mi

2018-04-01

Three inorganic-organic hybrids have been designed by incorporating epoxy-modified silicone resin (ESR) with SiO2, Fe3O4 and their mixture in the application as the coating of Fe soft magnetic composites (SMCs). The introduced SiO2 nanoparticles are well dispersed in the ESR, while the Fe3O4 tends to agglomerate or even separate from the ESR. Simultaneous addition of the SiO2 and Fe3O4 gives rise to satisfactory distribution of both nanoparticles and optimized magnetic performance of the SMCs with high permeability (124.6) and low loss (807.8 mW/cm3). On one hand, introduction of the ferromagnetic Fe3O4 reduces the magnetic dilution effect, which is beneficial for improved magnetization and permeability. On the other hand, SiO2 incorporation prevents the agglomeration of the Fe3O4 nanoparticles and gives rise to increased electrical resistivity for reduced core loss as well as enhanced mechanical strength of the SMCs.

Relating the physical properties of volcanic rocks to the characteristics of ash generated by experimental abrasion

NASA Astrophysics Data System (ADS)

Buckland, Hannah M.; Eychenne, Julia; Rust, Alison C.; Cashman, Katharine V.

2018-01-01

Interactions between clasts in pyroclastic density currents (PDCs) generate volcanic ash that can be dispersed to the atmosphere in co-PDC plumes, and due to its small size, is far-travelled. We designed a series of experiments to determine the effects of pyroclast vesicularity and crystal content on the efficiency and type of ash generated by abrasion. Two different pyroclastic materials were used: (1) basaltic-andesite pyroclasts from Fuego volcano (Guatemala) with 26-46% vesicularity and high groundmass crystallinity and (2) tephri-phonolite Avellino pumice (Vesuvius, Italy) with 55-75% vesicularity and low groundmass crystallinity. When milled, both clast types produced bimodal grain size distributions with fine ash modes between 4 and 5φ (32-63 μm). Although the vesicular Avellino pumice typically generated more ash than the denser Fuego pyroclasts, the ash-generating potential of a single pyroclast was independent of density, and instead governed by heterogeneous crystal and vesicle textures. One consequence of these heterogeneities was to cause the vesicular Avellino clasts to split in addition to abrading, which further enhanced abrasion efficiency. The matrix characteristics also affected ash shape and componentry, which will influence the elutriation and transport properties of ash in the atmosphere. The experimental abrasion successfully replicated some of the characteristics of natural co-PDC ash samples, as shown by similarities in the Adherence Factor, which measures the proportion of attached matrix on phenocrysts, of both the experimentally generated ash and natural co-PDC ash samples. Our results support previous studies, which have shown that abrasion is an effective mechanism for generating fine ash that is similar in size ( 5φ; 30 μm) to that found in co-PDC deposits. We further show that both the abundance and nature (shape, density, components, size distribution) of those ash particles are strongly controlled by the matrix properties of the abraded pyroclasts.

Enhancement of mercury capture by the simultaneous addition of hydrogen bromide (HBr) and fly ashes in a slipstream facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan Cao; Quan-Hai Wang; Jun Li

2009-04-15

Low halogen content in tested Powder River Basin (PRB) coals and low loss of ignition content (LOI) in PRB-derived fly ash were likely responsible for higher elemental mercury content (averaging about 75%) in the flue gas and also lower mercury capture efficiency by electrostatic precipitator (ESP) and wet-FGD. To develop a cost-effective approach to mercury capture in a full-scale coal-fired utility boiler burning PRB coal, experiments were conducted adding hydrogen bromide (HBr) or simultaneously adding HBr and selected fly ashes in a slipstream reactor (0.152 x 0.152 m) under real flue gas conditions. The residence time of the flue gasmore » inside the reactor was about 1.4 s. The average temperature of the slipstream reactor was controlled at about 155{sup o}C. Tests were organized into two phases. In Phase 1, only HBr was added to the slipstream reactor, and in Phase 2, HBr and selected fly ash were added simultaneously. HBr injection was effective (>90%) for mercury oxidation at a low temperature (155{sup o}C) with an HBr addition concentration of about 4 ppm in the flue gas. Additionally, injected HBr enhanced mercury capture by PRB fly ash in the low-temperature range. The mercury capture efficiency, at testing conditions of the slipstream reactor, reached about 50% at an HBr injection concentration of 4 ppm in the flue gas. Compared to only the addition of HBr, simultaneously adding bituminous-derived fly ash in a minimum amount (30 lb/MMacf), together with HBr injection at 4 ppm, could increase mercury capture efficiency by 30%. Injection of lignite-derived fly ash at 30 lb/MMacf could achieve even higher mercury removal efficiency (an additional 35% mercury capture efficiency compared to HBR addition alone). 25 refs., 5 figs., 1 tab.« less

Mobility and settling rate of agglomerates of polydisperse nanoparticles.

PubMed

Spyrogianni, Anastasia; Karadima, Katerina S; Goudeli, Eirini; Mavrantzas, Vlasis G; Pratsinis, Sotiris E

2018-02-14

Agglomerate settling impacts nanotoxicology and nanomedicine as well as the stability of engineered nanofluids. Here, the mobility of nanostructured fractal-like SiO 2 agglomerates in water is investigated and their settling rate in infinitely dilute suspensions is calculated by a Brownian dynamics algorithm tracking the agglomerate translational and rotational motion. The corresponding friction matrices are obtained using the HYDRO++ algorithm [J. G. de la Torre, G. del Rio Echenique, and A. Ortega, J. Phys. Chem. B 111, 955 (2007)] from the Kirkwood-Riseman theory accounting for hydrodynamic interactions of primary particles (PPs) through the Rotne-Prager-Yamakawa tensor, properly modified for polydisperse PPs. Agglomerates are generated by an event-driven method and have constant mass fractal dimension but varying PP size distribution, mass, and relative shape anisotropy. The calculated diffusion coefficient from HYDRO++ is used to obtain the agglomerate mobility diameter d m and is compared with that from scaling laws for fractal-like agglomerates. The ratio d m /d g of the mobility diameter to the gyration diameter of the agglomerate decreases with increasing relative shape anisotropy. For constant d m and mean d p , the agglomerate settling rate, u s , increases with increasing PP geometric standard deviation σ p,g (polydispersity). A linear relationship between u s and agglomerate mass to d m ratio, m/d m , is revealed and attributed to the fast Brownian rotation of such small and light nanoparticle agglomerates. An analytical expression for the u s of agglomerates consisting of polydisperse PPs is then derived, u s =1-ρ f ρ p g3πμmd m (ρ f is the density of the fluid, ρ p is the density of PPs, μ is the viscosity of the fluid, and g is the acceleration of gravity), valid for agglomerates for which the characteristic rotational time is considerably shorter than their settling time. Our calculations demonstrate that the commonly made assumption of monodisperse PPs underestimates u s by a fraction depending on σ p,g and agglomerate mass mobility exponent. Simulations are in excellent agreement with deposition rate measurements of fumed SiO 2 agglomerates in water.

Mobility and settling rate of agglomerates of polydisperse nanoparticles

NASA Astrophysics Data System (ADS)

Spyrogianni, Anastasia; Karadima, Katerina S.; Goudeli, Eirini; Mavrantzas, Vlasis G.; Pratsinis, Sotiris E.

2018-02-01

Agglomerate settling impacts nanotoxicology and nanomedicine as well as the stability of engineered nanofluids. Here, the mobility of nanostructured fractal-like SiO2 agglomerates in water is investigated and their settling rate in infinitely dilute suspensions is calculated by a Brownian dynamics algorithm tracking the agglomerate translational and rotational motion. The corresponding friction matrices are obtained using the HYDRO++ algorithm [J. G. de la Torre, G. del Rio Echenique, and A. Ortega, J. Phys. Chem. B 111, 955 (2007)] from the Kirkwood-Riseman theory accounting for hydrodynamic interactions of primary particles (PPs) through the Rotne-Prager-Yamakawa tensor, properly modified for polydisperse PPs. Agglomerates are generated by an event-driven method and have constant mass fractal dimension but varying PP size distribution, mass, and relative shape anisotropy. The calculated diffusion coefficient from HYDRO++ is used to obtain the agglomerate mobility diameter dm and is compared with that from scaling laws for fractal-like agglomerates. The ratio dm/dg of the mobility diameter to the gyration diameter of the agglomerate decreases with increasing relative shape anisotropy. For constant dm and mean dp, the agglomerate settling rate, us, increases with increasing PP geometric standard deviation σp,g (polydispersity). A linear relationship between us and agglomerate mass to dm ratio, m/dm, is revealed and attributed to the fast Brownian rotation of such small and light nanoparticle agglomerates. An analytical expression for the us of agglomerates consisting of polydisperse PPs is then derived, us=(1/-{ρf/ρp})g 3 π μ m/dm (ρf is the density of the fluid, ρp is the density of PPs, μ is the viscosity of the fluid, and g is the acceleration of gravity), valid for agglomerates for which the characteristic rotational time is considerably shorter than their settling time. Our calculations demonstrate that the commonly made assumption of monodisperse PPs underestimates us by a fraction depending on σp,g and agglomerate mass mobility exponent. Simulations are in excellent agreement with deposition rate measurements of fumed SiO2 agglomerates in water.

Effect of Mass Proportion of Municipal Solid Waste Incinerator Bottom Ash Layer to Municipal Solid Waste Layer on the Cu and Zn Discharge from Landfill

PubMed Central

Kong, Qingna; Qiu, Zhanhong; Shen, Dongsheng

2016-01-01

Municipal solid waste incinerator (MSWI) bottom ash is often used as the protection layer for the geomembrane and intermediate layer in the landfill. In this study, three sets of simulated landfills with different mass proportion of MSWI bottom ash layer to municipal solid waste (MSW) layer were operated. Cu and Zn concentrations in the leachates and MSW were monitored to investigate the effect of MSWI bottom ash layer on the Cu and Zn discharge from the landfill. The results showed that the Zn discharge was dependent on the mass proportion of MSWI bottom ash layer. The pH of landfill was not notably increased when the mass proportion of MSWI bottom ash layer to MSW layer was 1 : 9, resulting in the enhancement of the Zn discharge. However, Zn discharge was mitigated when the mass proportion was 2 : 8, as the pH of landfill was notably promoted. The discharge of Cu was not dependent on the mass proportion, due to the great affinity of Cu to organic matter. Moreover, Cu and Zn contents of the sub-MSW layer increased due to the MSWI bottom ash layer. Therefore, the MSWI bottom ash layer can increase the potential environmental threat of the landfill. PMID:28044139

Mechanical and Durability Properties of Fly Ash Based Concrete Exposed to Marine Environment

NASA Astrophysics Data System (ADS)

Kagadgar, Sarfaraz Ahmed; Saha, Suman; Rajasekaran, C.

2017-06-01

Efforts over the past few years for improving the performance of concrete suggest that cement replacement with mineral admixtures can enhance the strength and durability of concrete. Feasibility of producing good quality concrete by using alccofine and fly ash replacements is investigated and also the potential benefits from their incorporation were looked into. In this study, an attempt has been made to assess the performance of concrete in severe marine conditions exposed upto a period of 150 days. This work investigates the influence of alccofine and fly ash as partial replacement of cement in various percentages (Alccofine - 5% replacement to cement content) and (fly ash - 0%, 15%, 30%, 50% & 60% to total cementitious content) on mechanical and durability properties (Permit ion permeability test and corrosion current density) of concrete. Usage of alccofine and high quantity of fly ash as additional cementitious materials in concrete has resulted in higher workability of concrete. Inclusion of alccofine shows an early strength gaining property whereas fly ash results in gaining strength at later stage. Concrete mixes containing 5% alccofine with 15% fly ash replacement reported greater compressive strength than the other concrete mixes cured in both curing conditions. Durability test conducted at 56 and 150 days indicated that concrete containing higher percentages of fly ash resulted in lower permeability as well lesser corrosion density.

Evaluating Growth of Zeolites on Fly Ash in Hydro-Thermally Heated Low Alkaline Solution

NASA Astrophysics Data System (ADS)

Jha, Bhagwanjee; Singh, D. N.

2017-12-01

Fly ash has been well established materials for synthesis of zeolites, under hydrothermally heated aqueous NaOH solution. Efficacy of such technique is reported to be improved when high molarity of NaOH is used. Consequently, highly alkaline waste solution, as by-product, is generally disposed of in the surrounding, which may contaminate the environment. In this context, less alkaline NaOH solution may become a safer option, which has not been tried in the past as per the literature. With this in view, the present study demonstrates effectiveness of the 0.5 M NaOH solution and critically monitors transition on the fly ash after hydrothermal treatment. As an enhancement over previous researchers, such activation of the fly ash finally results in remarkable morphological and mineralogical growth on the bulk material (the residue), which comprises of new nano-sized crystals (the zeolites Na-P1 and natrolite), after 24 h of activation of the fly ash.

Compressive strength performance of OPS lightweight aggregate concrete containing coal bottom ash as partial fine aggregate replacement

NASA Astrophysics Data System (ADS)

Muthusamy, K.; Mohamad Hafizuddin, R.; Mat Yahaya, F.; Sulaiman, M. A.; Syed Mohsin, S. M.; Tukimat, N. N.; Omar, R.; Chin, S. C.

2018-04-01

Concerns regarding the negative impact towards environment due to the increasing use of natural sand in construction industry and dumping of industrial solid wastes namely coal bottom ash (CBA) and oil palm shell (OPS) has resulted in the development of environmental friendly lightweight concrete. The present study investigates the effect of coal bottom ash as partial fine aggregate replacement towards workability and compressive strength of oil palm shell lightweight aggregate concrete (OPS LWAC). The fresh and mechanical properties of this concrete containing various percentage of coal bottom ash as partial fine aggregate replacement were investigated. The result was compared to OPS LWAC with 100 % sand as a control specimen. The concrete workability investigated by conducting slump test. All specimens were cast in form of cubes and water cured until the testing age. The compressive strength test was carried out at 7 and 28 days. The finding shows that integration of coal bottom ash at suitable proportion enhances the strength of oil palm shell lightweight aggregate concrete.

Agricultural wastes as a resource of raw materials for developing low-dielectric glass-ceramics

PubMed Central

Danewalia, Satwinder Singh; Sharma, Gaurav; Thakur, Samita; Singh, K.

2016-01-01

Agricultural waste ashes are used as resource materials to synthesize new glass and glass-ceramics. The as-prepared materials are characterized using various techniques for their structural and dielectric properties to check their suitability in microelectronic applications. Sugarcane leaves ash exhibits higher content of alkali metal oxides than rice husk ash, which reduces the melting point of the components due to eutectic reactions. The addition of sugarcane leaves ash in rice husk ash promotes the glass formation. Additionally, it prevents the cristobalite phase formation. These materials are inherently porous, which is responsible for low dielectric permittivity i.e. 9 to 40. The presence of less ordered augite phase enhances the dielectric permittivity as compared to cristobalite and tridymite phases. The present glass-ceramics exhibit lower losses than similar materials synthesized using conventional minerals. The dielectric permittivity is independent to a wide range of temperature and frequency. The glass-ceramics developed with adequately devitrified phases can be used in microelectronic devices and other dielectric applications. PMID:27087123

Kinetic energy density and agglomerate abrasion rate during blending of agglomerates into powders.

PubMed

Willemsz, Tofan A; Hooijmaijers, Ricardo; Rubingh, Carina M; Tran, Thanh N; Frijlink, Henderik W; Vromans, Herman; van der Voort Maarschalk, Kees

2012-01-23

Problems related to the blending of a cohesive powder with a free flowing bulk powder are frequently encountered in the pharmaceutical industry. The cohesive powder often forms lumps or agglomerates which are not dispersed during the mixing process and are therefore detrimental to blend uniformity. Achieving sufficient blend uniformity requires that the blending conditions are able to break up agglomerates, which is often an abrasion process. This study was based on the assumption that the abrasion rate of agglomerates determines the required blending time. It is shown that the kinetic energy density of the moving powder bed is a relevant parameter which correlates with the abrasion rate of agglomerates. However, aspects related to the strength of agglomerates should also be considered. For this reason the Stokes abrasion number (St(Abr)) has been defined. This parameter describes the ratio between the kinetic energy density of the moving powder bed and the work of fracture of the agglomerate. The St(Abr) number is shown to predict the abrasion potential of agglomerates in the dry-mixing process. It appeared possible to include effects of filler particle size and impeller rotational rate into this concept. A clear relationship between abrasion rate of agglomerates and the value of St(Abr) was demonstrated. Copyright © 2011 Elsevier B.V. All rights reserved.

Ion Beam Analyses Of Bark And Wood In Environmental Studies

NASA Astrophysics Data System (ADS)

Lill, J.-O.; Saarela, K.-E.; Harju, L.; Rajander, J.; Lindroos, A.; Heselius, S.-J.

2011-06-01

A large number of wood and bark samples have been analysed utilizing particle-induced X-ray emission (PIXE) and particle-induced gamma-ray emission (PIGE) techniques. Samples of common tree species like Scots Pine, Norway Spruce and birch were collected from a large number of sites in Southern and Southwestern Finland. Some of the samples were from a heavily polluted area in the vicinity of a copper-nickel smelter. The samples were dry ashed at 550 °C for the removal of the organic matrix in order to increase the analytical sensitivity of the method. The sensitivity was enhanced by a factor of 50 for wood and slightly less for bark. The ashed samples were pressed into pellets and irradiated as thick targets with a millimetre-sized proton beam. By including the ashing procedure in the method, the statistical dispersion due to elemental heterogeneities in wood material could be reduced. As a by-product, information about the elemental composition of ashes was obtained. By comparing the concentration of an element in bark ash to the concentration in wood ash of the same tree useful information from environmental point of view was obtained. The obtained ratio of the ashes was used to distinguish between elemental contributions from anthropogenic atmospheric sources and natural geochemical sources, like soil and bedrock.

Production of thermal insulation blocks from bottom ash of fluidized bed combustion system.

PubMed

Mandal, A K; Sinha, O P

2017-08-01

The issues of disposal and environmental problems are increased by the generation of bottom ash from the thermal power plants day by day; hence, its recycling is required. The present study aimed to make thermal insulation blocks using as raw material bottom ash and iron ore slime as a binder and to characterize their engineering properties. Two different fineness values of bottom ash were considered with varying amounts of iron ore slime (0-10%) to make the blocks. Blocks were dried followed by firing at 1000, 1100 and 1200°C, respectively. Cold crushing strength, density and thermal conductivity of these fired blocks showed increasing behaviour with firing temperature, fineness of bottom ash and iron ore slime content. In contrast, a reverse trend was observed in the case of porosity. With increasing firing temperature, the formation of lower melting phases like iron silicate followed by iron aluminium silicate was observed, which imparts the strength inside the blocks. The coarser particles of bottom ash increase the interparticle spaces, which enhances the apparent porosity, resulting in higher thermal insulation property in the blocks. Blocks having better thermal insulation property could be possible to make effectively from coarse bottom ash by adding iron ore slime as a binder.

Thermal and hydrometallurgical recovery methods of heavy metals from municipal solid waste fly ash.

PubMed

Kuboňová, L; Langová, Š; Nowak, B; Winter, F

2013-11-01

Heavy metals in fly ash from municipal solid waste incinerators are present in high concentrations. Therefore fly ash must be treated as a hazardous material. On the other hand, it may be a potential source of heavy metals. Zinc, lead, cadmium, and copper can be relatively easily removed during the thermal treatment of fly ash, e.g. in the form of chlorides. In return, wet extraction methods could provide promising results for these elements including chromium and nickel. The aim of this study was to investigate and compare thermal and hydrometallurgical treatment of municipal solid waste fly ash. Thermal treatment of fly ash was performed in a rotary reactor at temperatures between 950 and 1050°C and in a muffle oven at temperatures from 500 to 1200°C. The removal more than 90% was reached by easy volatile heavy metals such as cadmium and lead and also by copper, however at higher temperature in the muffle oven. The alkaline (sodium hydroxide) and acid (sulphuric acid) leaching of the fly ash was carried out while the influence of temperature, time, concentration, and liquid/solid ratio were investigated. The combination of alkaline-acidic leaching enhanced the removal of, namely, zinc, chromium and nickel. Copyright © 2013 Elsevier Ltd. All rights reserved.

Staged mold for encapsulating hazardous wastes

DOEpatents

Unger, Samuel L.; Telles, Rodney W.; Lubowitz, Hyman R.

1990-01-01

A staged mold for stabilizing hazardous wastes for final disposal by molding an agglomerate of the hazardous wastes and encapsulating the agglomerate. Three stages are employed in the process. In the first stage, a first mold body is positioned on a first mold base, a mixture of the hazardous wastes and a thermosetting plastic is loaded into the mold, the mixture is mechanically compressed, heat is applied to cure the mixture to form a rigid agglomerate, and the first mold body is removed leaving the agglomerate sitting on the first mold base. In the second stage, a clamshell second mold body is positioned around the agglomerate and the first mold base, a powdered thermoplastic resin is poured on top of the agglomerate and in the gap between the sides of the agglomerate and the second mold body, the thermoplastic is compressed, heat is applied to melt the thermoplastic, and the plastic is cooled jacketing the agglomerate on the top and sides. In the third stage, the mold with the jacketed agglomerate is inverted, the first mold base is removed exposing the former bottom of the agglomerate, powdered thermoplastic is poured over the former bottom, the first mold base is replaced to compress the thermoplastic, heat is applied to melt the new thermoplastic and the top part of the jacket on the sides, the plastic is cooled jacketing the bottom and fusing with the jacketing on the sides to complete the seamless encapsulation of the agglomerate.

Staged mold for encapsulating hazardous wastes

DOEpatents

Unger, Samuel L.; Telles, Rodney W.; Lubowitz, Hyman R.

1988-01-01

A staged mold for stabilizing hazardous wastes for final disposal by molding an agglomerate of the hazardous wastes and encapsulating the agglomerate. Three stages are employed in the process. In the first stage, a first mold body is positioned on a first mold base, a mixture of the hazardous wastes and a thermosetting plastic is loaded into the mold, the mixture is mechanically compressed, heat is applied to cure the mixture to form a rigid agglomerate, and the first mold body is removed leaving the agglomerate sitting on the first mold base. In the second stage, a clamshell second mold body is positioned around the agglomerate and the first mold base, a powdered thermoplastic resin is poured on top of the agglomerate and in the gap between the sides of the agglomerate and the second mold body, the thermoplastic is compressed, heat is applied to melt the thermoplastic, and the plastic is cooled jacketing the agglomerate on the top and sides. In the third stage, the mold with the jacketed agglomerate is inverted, the first mold base is removed exposing the former bottom of the agglomerate, powdered thermoplastic is poured over the former bottom, the first mold base is replaced to compress the thermoplastic, heat is applied to melt the new thermoplastic and the top part of the jacket on the sides, the plastic is cooled jacketing the bottom and fusing with the jacketing on the sides to complete the seamless encapsulation of the agglomerate.

Method for encapsulating hazardous wastes using a staged mold

DOEpatents

Unger, Samuel L.; Telles, Rodney W.; Lubowitz, Hyman R.

1989-01-01

A staged mold and method for stabilizing hazardous wastes for final disposal by molding an agglomerate of the hazardous wastes and encapsulating the agglomerate. Three stages are employed in the process. In the first stage, a first mold body is positioned on a first mold base, a mixture of the hazardous wastes and a thermosetting plastic is loaded into the mold, the mixture is mechanically compressed, heat is applied to cure the mixture to form a rigid agglomerate, and the first mold body is removed leaving the agglomerate sitting on the first mold base. In the second stage, a clamshell second mold body is positioned around the agglomerate and the first mold base, a powdered thermoplastic resin is poured on top of the agglomerate and in the gap between the sides of the agglomerate and the second mold body, the thermoplastic is compressed, heat is applied to melt the thermoplastic, and the plastic is cooled jacketing the agglomerate on the top and sides. In the third stage, the mold with the jacketed agglomerate is inverted, the first mold base is removed exposing the former bottom of the agglomerate, powdered thermoplastic is poured over the former bottom, the first mold base is replaced to compress the thermoplastic, heat is applied to melt the new thermoplastic and the top part of the jacket on the sides, the plastic is cooled jacketing the bottom and fusing with the jacketing on the sides to complete the seamless encapsulation of the agglomerate.

Open-cell glass crystalline porous material

DOEpatents

Anshits, Alexander G.; Sharonova, Olga M.; Vereshchagina, Tatiana A.; Zykova, Irina D.; Revenko, Yurii A.; Tretyakov, Alexander A.; Aloy, Albert S.; Lubtsev, Rem I.; Knecht, Dieter A.; Tranter, Troy J.; Macheret, Yevgeny

2002-01-01

An open-cell glass crystalline porous material made from hollow microspheres which are cenospheres obtained from fly ash, having an open-cell porosity of up to 90 vol. % is produced. The cenospheres are separated into fractions based on one or more of grain size, density, magnetic or non-magnetic, and perforated or non-perforated. Selected fractions are molded and agglomerated by sintering with a binder at a temperature below the softening temperature, or without a binder at a temperature about, or above, the softening temperature but below the temperature of liquidity. The porous material produced has an apparent density of 0.3-0.6 g/cm.sup.3, a compressive strength in the range of 1.2-3.5 MPa, and two types of openings: through-flow wall pores in the cenospheres of 0.1-30 micrometers, and interglobular voids between the cenospheres of 20-100 micrometers. The porous material of the invention has properties useful as porous matrices for immobilization of liquid radioactive waste, heat-resistant traps and filters, supports for catalysts, adsorbents and ion-exchangers.

Open-cell glass crystalline porous material

DOEpatents

Anshits, Alexander G.; Sharonova, Olga M.; Vereshchagina, Tatiana A.; Zykova, Irina D.; Revenko, Yurii A.; Tretyakov, Alexander A.; Aloy, Albert S.; Lubtsev, Rem I.; Knecht, Dieter A.; Tranter, Troy J.; Macheret, Yevgeny

2003-12-23

An open-cell glass crystalline porous material made from hollow microspheres which are cenospheres obtained from fly ash, having an open-cell porosity of up to 90 vol. % is produced. The cenospheres are separated into fractions based on one or more of grain size, density, magnetic or non-magnetic, and perforated or non-perforated. Selected fractions are molded and agglomerated by sintering with a binder at a temperature below the softening temperature, or without a binder at a temperature about, or above, the softening temperature but below the temperature of liquidity. The porous material produced has an apparent density of 0.3-0.6 g/cm.sup.3, a compressive strength in the range of 1.2-3.5 MPa, and two types of openings: through-flow wall pores in the cenospheres of 0.1-30 micrometers, and interglobular voids between the cenospheres of 20-100 micrometers. The porous material of the invention has properties useful as porous matrices for immobilization of liquid radioactive waste, heat-resistant traps and filters, supports for catalysts, adsorbents and ion-exchangers.

Westinghouse to launch coal gasifier with combined cycle unit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stavsky, R.M.; Margaritis, P.J.

1980-03-01

Following an extensive test program with a prototype coal gasifier, Westinghouse Electric Corp. is now offering an integrated gasifier/combined-cycle unit as a feasible alternative for generating power from coal in an efficient, clean manner. The Westinghouse gasification process uses a single-stage pressurized fluidized-bed reactor, followed by heat recovery, gas cleaning, sulfur and amonia removal and recovery, and gas reheat. The system produces a fuel gas free of sulfur and other contaminants from crushed run-of-mine coals of varying reactivities and caking properties. The by-products include ammonia and sulfur and an agglomerated ash residue that serves as an acceptable landfill. Air formore » the gasifier is bled from the gas-turbine air compressor and further pressurized with a booster compressor. The hot exhaust gases from the gas turbine pass through a heat-recovery steam generator that produces sufficient steam to drive a turbine providing about 40% of the total electricity generated in the plant.« less

SERS of Methylene Blue induced by plasmonic coupled nanoparticle arrays

NASA Astrophysics Data System (ADS)

Kaydashev, V. E.; Lyanguzov, N. V.; Anokhin, A. S.; Chernishov, A.; Kaidashev, E. M.

2018-04-01

We study the surface enhanced Raman scattering of Methylene Blue (MB) dye molecules induced by large quasihomogeneous arrays of plasmon coupled 5-8 nm Au nanoparticle separated by distances less than 10 nm. Also, the variation of the fluorescence enhancement/SERS properties for as-prepared coupled particles and agglomerated particles obtained upon heat treatment and percolation-like films is analyzed for two measurement protocols, i.e. when measured through the solution and for a monolayer of MB molecules chemisorbed on a surface.

Magnetic Thermometer: Thermal effect on the Agglomeration of Magnetic Nanoparticles by Magnetic field

NASA Astrophysics Data System (ADS)

Jin, Daeseong; Kim, Hackjin

2018-03-01

We have investigated the agglomeration of magnetite nanoparticles in the aqueous solution under magnetic field by measuring temporal change of magnetic weight. The magnetic weight corresponds to the force due to the magnetization of magnetic materials. Superparamagnetic magnetite nanoparticles are synthesized and used in this work. When the aqueous solution of magnetite nanoparticle is placed under magnetic field, the magnetic weight of the sample jumps instantaneously by Neel and Brown mechanisms and thereafter increases steadily following a stretched exponential function as the nanoparticles agglomerate, which results from the distribution of energy barriers involved in the dynamics. Thermal motions of nanoparticles in the agglomerate perturb the ordered structure of the agglomerate to reduce the magnetic weight. Fluctuation of the structural order of the agglomerate by temperature change is much faster than the formation of agglomerate and explained well with the Boltzmann distribution, which suggests that the magnetic weight of the agglomerate works as a magnetic thermometer.

Atmospheric processes affecting the separation of volcanic ash and SO2 in volcanic eruptions: inferences from the May 2011 Grímsvötn eruption

NASA Astrophysics Data System (ADS)

Prata, Fred; Woodhouse, Mark; Huppert, Herbert E.; Prata, Andrew; Thordarson, Thor; Carn, Simon

2017-09-01

The separation of volcanic ash and sulfur dioxide (SO2) gas is sometimes observed during volcanic eruptions. The exact conditions under which separation occurs are not fully understood but the phenomenon is of importance because of the effects volcanic emissions have on aviation, on the environment, and on the earth's radiation balance. The eruption of Grímsvötn, a subglacial volcano under the Vatnajökull glacier in Iceland during 21-28 May 2011 produced one of the most spectacular examples of ash and SO2 separation, which led to errors in the forecasting of ash in the atmosphere over northern Europe. Satellite data from several sources coupled with meteorological wind data and photographic evidence suggest that the eruption column was unable to sustain itself, resulting in a large deposition of ash, which left a low-level ash-rich atmospheric plume moving southwards and then eastwards towards the southern Scandinavian coast and a high-level predominantly SO2 plume travelling northwards and then spreading eastwards and westwards. Here we provide observational and modelling perspectives on the separation of ash and SO2 and present quantitative estimates of the masses of ash and SO2 that erupted, the directions of transport, and the likely impacts. We hypothesise that a partial column collapse or sloughing fed with ash from pyroclastic density currents (PDCs) occurred during the early stage of the eruption, leading to an ash-laden gravity intrusion that was swept southwards, separated from the main column. Our model suggests that water-mediated aggregation caused enhanced ash removal because of the plentiful supply of source water from melted glacial ice and from entrained atmospheric water. The analysis also suggests that ash and SO2 should be treated with separate source terms, leading to improvements in forecasting the movement of both types of emissions.

Advantageous GOES IR results for ash mapping at high latitudes: Cleveland eruptions 2001

USGS Publications Warehouse

Gu, Yingxin; Rose, William I.; Schneider, D.J.; Bluth, G.J.S.; Watson, I.M.

2005-01-01

The February 2001 eruption of Cleveland Volcano, Alaska allowed for comparisons of volcanic ash detection using two-band thermal infrared (10-12 ??m) remote sensing from MODIS, AVHRR, and GOES 10. Results show that high latitude GOES volcanic cloud sensing the range of about 50 to 65??N is significantly enhanced. For the Cleveland volcanic clouds the MODIS and AVHRR data have zenith angles 6-65 degrees and the GOES has zenith angles that are around 70 degrees. The enhancements are explained by distortion in the satellite view of the cloud's lateral extent because the satellite zenith angles result in a "side-looking" aspect and longer path lengths through the volcanic cloud. The shape of the cloud with respect to the GOES look angle also influences the results. The MODIS and AVHRR data give consistent retrievals of the ash cloud evolution over time and are good corrections for the GOES data. Copyright 2005 by the American Geophysical Union.

In-line agglomeration degree estimation in fluidized bed pellet coating processes using visual imaging.

PubMed

Mehle, Andraž; Kitak, Domen; Podrekar, Gregor; Likar, Boštjan; Tomaževič, Dejan

2018-05-09

Agglomeration of pellets in fluidized bed coating processes is an undesirable phenomenon that affects the yield and quality of the product. In scope of PAT guidance, we present a system that utilizes visual imaging for in-line monitoring of the agglomeration degree. Seven pilot-scale Wurster coating processes were executed under various process conditions, providing a wide spectrum of process outcomes. Images of pellets were acquired during the coating processes in a contactless manner through an observation window of the coating apparatus. Efficient image analysis methods were developed for automatic recognition of discrete pellets and agglomerates in the acquired images. In-line obtained agglomeration degree trends revealed the agglomeration dynamics in distinct phases of the coating processes. We compared the in-line estimated agglomeration degree in the end point of each process to the results obtained by the off-line sieve analysis reference method. A strong positive correlation was obtained (coefficient of determination R 2 =0.99), confirming the feasibility of the approach. The in-line estimated agglomeration degree enables early detection of agglomeration and provides means for timely interventions to retain it in an acceptable range. Copyright © 2018 Elsevier B.V. All rights reserved.

Monitoring Volcanic Ash with MSG Seviri Image and RGB Application

NASA Astrophysics Data System (ADS)

Erturk, Aydin Gurol; Kerkman, Jochen

2011-01-01

The eruption from the Eyjafjallajökull Volcano, Iceland recently became a high importance for the Meteorological Institutes, Aviation, Satellite Centers and other related institutions. Urgent forecasts were requested by the air control centers, aviation industry and even the passengers who stuck at the airports. It was announced that thousands of flights are canceled; hundreds of thousands of passengers affected and the airlines lost around 1.7 billion dollars in April-May 2010. This is the worst aviation crises. MSG (METEOSAT Second Generation) SEVIRI (Spinning Enhanced Visible and Infrared Imagery) with its 11 narrow and 1 broad band channels have been providing a worth of data sources for nowcasting and very short forecasting. SEVIRI images and RGB applications have been acted an important role to monitor Volcanic Ash during above aviation crises. SEVIRI has an infrared channel (centered @8.7 micron) which is sensitive sand, dust and ash in the atmosphere. In this study we present Ash RGB applications derived from SEVIRI data to monitor and track Ash clouds over Europe. Two main eruptions during 14-20 April and 7-17 May 2010 will be demonstrated. In addition to this, we will propose an Ash product algorithm and discuss its weakness and strength.

Residual organic matter and microbial respiration in bottom ash: Effects on metal leaching and eco-toxicity.

PubMed

Ilyas, A; Persson, K M; Persson, M

2015-09-01

A common assumption regarding the residual organic matter, in bottom ash, is that it does not represent a significant pool of organic carbon and, beyond metal-ion complexation process, it is of little consequence to evolution of ash/leachate chemistry. This article evaluates the effect of residual organic matter and associated microbial respiratory processes on leaching of toxic metals (i.e. arsenic, copper, chromium, molybdenum, nickel, lead, antimony and zinc), eco-toxicity of ash leachates. Microbial respiration was quantified with help of a respirometric test equipment OXITOP control system. The effect of microbial respiration on metal/residual organic matter leaching and eco-toxicity was quantified with the help of batch leaching tests and an eco-toxicity assay - Daphnia magna. In general, the microbial respiration process decreased the leachate pH and eco-toxicity, indicating modification of bioavailability of metal species. Furthermore, the leaching of critical metals, such as copper and chromium, decreased after the respiration in both ash types (fresh and weathered). It was concluded that microbial respiration, if harnessed properly, could enhance the stability of fresh bottom ash and may promote its reuse. © The Author(s) 2015.

A model to estimate the size of nanoparticle agglomerates in gas-solid fluidized beds

NASA Astrophysics Data System (ADS)

de Martín, Lilian; van Ommen, J. Ruud

2013-11-01

The estimation of nanoparticle agglomerates' size in fluidized beds remains an open challenge, mainly due to the difficulty of characterizing the inter-agglomerate van der Waals force. The current approach is to describe micron-sized nanoparticle agglomerates as micron-sized particles with 0.1-0.2-μm asperities. This simplification does not capture the influence of the particle size on the van der Waals attraction between agglomerates. In this paper, we propose a new description where the agglomerates are micron-sized particles with nanoparticles on the surface, acting as asperities. As opposed to previous models, here the van der Waals force between agglomerates decreases with an increase in the particle size. We have also included an additional force due to the hydrogen bond formation between the surfaces of hydrophilic and dry nanoparticles. The average size of the fluidized agglomerates has been estimated equating the attractive force obtained from this method to the weight of the individual agglomerates. The results have been compared to 54 experimental values, most of them collected from the literature. Our model approximates without a systematic error the size of most of the nanopowders, both in conventional and centrifugal fluidized beds, outperforming current models. Although simple, the model is able to capture the influence of the nanoparticle size, particle density, and Hamaker coefficient on the inter-agglomerate forces.

Emerald ash borer and the urban forest: Changes in landslide potential due to canopy loss scenarios in the City of Pittsburgh, PA.

PubMed

Pfeil-McCullough, Erin; Bain, Daniel J; Bergman, Jeffery; Crumrine, Danielle

2015-12-01

Emerald ash borer is expected to kill thousands of ash trees in the eastern U.S. This research develops tools to predict the effect of ash tree loss from the urban canopy on landslide susceptibility in Pittsburgh, PA. A spatial model was built using the SINMAP (Stability INdex MAPping) model coupled with spatially explicit scenarios of tree loss (0%, 25%, 50%, and 75% loss of ash trees from the canopy). Ash spatial distributions were estimated via Monte Carlo methods and available vegetation plot data. Ash trees are most prevalent on steeper slopes, likely due to urban development patterns. Therefore, ash loss disproportionately increases hillslope instability. A 75% loss of ash resulted in roughly 800 new potential landslide initiation locations. Sensitivity testing reveals that variations in rainfall rates, and friction angles produce minor changes to model results relative to the magnitude of parameter variation, but reveal high model sensitivity to soil density and root cohesion values. The model predictions demonstrate the importance of large canopy species to urban hillslope stability, particularly on steep slopes and in areas where soils tend to retain water. To improve instability predictions, better characterization of urban soils, particularly spatial patterns of compaction and species specific root cohesion is necessary. The modeling framework developed in this research will enhance assessment of changes in landslide risk due to tree mortality, improving our ability to design economically and ecologically sustainable urban systems. Copyright © 2015 Elsevier B.V. All rights reserved.

Process and apparatus for coal hydrogenation

DOEpatents

Ruether, John A.

1988-01-01

In a coal liquefaction process an aqueous slurry of coal is prepared containing a dissolved liquefaction catalyst. A small quantity of oil is added to the slurry and then coal-oil agglomerates are prepared by agitation of the slurry at atmospheric pressure. The resulting mixture of agglomerates, excess water, dissolved catalyst, and unagglomerated solids is pumped to reaction pressure and then passed through a drainage device where all but a small amount of surface water is removed from the agglomerates. Sufficient catalyst for the reaction is contained in surface water remaining on the agglomerates. The agglomerates fall into the liquefaction reactor countercurrently to a stream of hot gas which is utilized to dry and preheat the agglomerates as well as deposit catalyst on the agglomerates before they enter the reactor where they are converted to primarily liquid products under hydrogen pressure.

Bed material agglomeration during fluidized bed combustion. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, R.C.; Dawson, M.R.; Smeenk, J.L.

The purpose of this project is to determine the physical and chemical reactions which lead to the undesired agglomeration of bed material during fluidized bed combustion of coal and to relate these reactions to specific causes. A survey of agglomeration and deposit formation in industrial fluidized bed combustors (FBCs) indicate that at least five boilers were experiencing some form of bed material agglomeration. Deposit formation was reported at nine sites with deposits most commonly at coal feed locations and in cyclones. Other deposit locations included side walls and return loops. Three general types of mineralogic reactions were observed to occurmore » in the agglomerates and deposits. Although alkalies may play a role with some {open_quotes}high alkali{close_quotes} lignites, we found agglomeration was initiated due to fluxing reactions between iron (II) from pyrites and aluminosilicates from clays. This is indicated by the high amounts of iron, silica, and alumina in the agglomerates and the mineralogy of the agglomerates. Agglomeration likely originated in the dense phase of the FBC bed within the volatile plume which forms when coal is introduced to the boiler. Secondary mineral reactions appear to occur after the agglomerates have formed and tend to strengthen the agglomerates. When calcium is present in high amounts, most of the minerals in the resulting deposits are in the melilite group (gehlenite, melilite, and akermanite) and pyroxene group (diopside and augite). During these solid-phase reactions, the temperature of formation of the melilite minerals can be lowered by a reduction of the partial pressure of CO{sub 2} (Diopside + Calcite {r_arrow}Akermanite).« less

Bi-functional ion exchangers for enhanced performance of dye-sensitized solar cells.

PubMed

Kong, Eui-Hyun; Chang, Yong-June; Lim, Jongchul; Kim, Back-Hyun; Lee, Jung-Hoon; Kwon, Do-Kyun; Park, Taiho; Jang, Hyun Myung

2013-07-28

Ion exchange using aerosol OT (AOT) offers dye adsorption twice as fast as known methods. Moreover, it suppresses the dye-agglomeration that may cause insufficient dye-coverage on the photoelectrode surface. Consequently, its dual function of fast dye-loading and higher dye-coverage significantly improves the power conversion efficiency of dye-sensitized solar cells.

Method for providing improved solid fuels from agglomerated subbituminous coal

DOEpatents

Janiak, Jerzy S.; Turak, Ali A.; Pawlak, Wanda; Ignasiak, Boleslaw L.

1989-01-01

A method is provided for separating agglomerated subbituminous coal and the heavy bridging liquid used to form the agglomerates. The separation is performed by contacting the agglomerates with inert gas or steam at a temperature in the range of 250.degree. to 350.degree. C. at substantially atmospheric pressure.

Investigation of methods to produce a uniform cloud of fuel particles in a flame tube

NASA Technical Reports Server (NTRS)

Siegert, Clifford E.; Pla, Frederic G.; Rubinstein, Robert; Niezgoda, Thomas F.; Burns, Robert J.; Johnson, Jerome A.

1990-01-01

The combustion of a uniform, quiescent cloud of 30-micron fuel particles in a flame tube was proposed as a space-based, low-gravity experiment. The subject is the normal- and low-gravity testing of several methods to produce such a cloud, including telescoping propeller fans, air pumps, axial and quadrature acoustical speakers, and combinations of these devices. When operated in steady state, none of the methods produced an acceptably uniform cloud (+ or - 5 percent of the mean concentration), and voids in the cloud were clearly visible. In some cases, severe particle agglomeration was observed; however, these clusters could be broken apart by a short acoustic burst from an axially in-line speaker. Analyses and experiments reported elsewhere suggest that transient, acoustic mixing methods can enhance cloud uniformity while minimizing particle agglomeration.

Powder agglomeration in a microgravity environment

NASA Technical Reports Server (NTRS)

Cawley, James D.

1994-01-01

This is the final report for NASA Grant NAG3-755 entitled 'Powder Agglomeration in a Microgravity Environment.' The research program included both two types of numerical models and two types of experiments. The numerical modeling included the use of Monte Carlo type simulations of agglomerate growth including hydrodynamic screening and molecular dynamics type simulations of the rearrangement of particles within an agglomerate under a gravitational field. Experiments included direct observation of the agglomeration of submicron alumina and indirect observation, using small angle light scattering, of the agglomeration of colloidal silica and aluminum monohydroxide. In the former class of experiments, the powders were constrained to move on a two-dimensional surface oriented to minimize the effect of gravity. In the latter, some experiments involved mixture of suspensions containing particles of opposite charge which resulted in agglomeration on a very short time scale relative to settling under gravity.

[Effects of Chinese prickly ash orchard on soil organic carbon mineralization and labile organic carbon in karst rocky desertification region of Guizhou province].

PubMed

Zhang, Wen-Juan; Liao, Hong-Kai; Long, Jian; Li, Juan; Liu, Ling-Fei

2015-03-01

Taking 5-year-old Chinese prickly ash orchard (PO-5), 17-year-old Chinese prickly ash orchard (PO- 17), 30-year-old Chinese prickly ash orchard (PO-30) and the forest land (FL, about 60 years) in typical demonstration area of desertification control test in southwestern Guizhou as our research objects, the aim of this study using a batch incubation experiment was to research the mineralization characteristics of soil organic carbon and changes of the labile soil organic carbon contents at different depths (0-15 cm, 15-30 cm, and 30-50 cm). The results showed that: the cumulative mineralization amounts of soil organic carbon were in the order of 30-year-old Chinese prickly ash orchard, the forest land, 5-year-old Chinese prickly ash orchard and 17-year-old Chinese prickly ash orchard at corresponding depth. Distribution ratios of CO2-C cumulative mineralization amount to SOC contents were higher in Chinese prickly ash orchards than in forest land at each depth. Cultivation of Chinese prickly ash in long-term enhanced the mineralization of soil organic carbon, and decreased the stability of soil organic carbon. Readily oxidized carbon and particulate organic carbon in forest land soils were significantly more than those in Chinese prickly ash orchards at each depth (P < 0.05). With the increasing times of cultivation of Chinese prickly ash, the contents of readily oxidized carbon and particulate organic carbon first increased and then declined at 0-15 cm and 15-30 cm depth, respectively, but an opposite trend was found at 30-50 cm depth. At 0-15 cm and 15-30 cm, cultivation of Chinese prickly ash could be good for improving the contents of labile soil organic carbon in short term, but it was not conducive in long-term. In this study, we found that cultivation of Chinese prickly ash was beneficial for the accumulation of labile organic carbon at the 30-50 cm depth.

Holocene dune formation at Ash Meadows National Wildlife Area, Nevada, USA

USGS Publications Warehouse

Lancaster, Nicholas; Mahan, Shannon

2012-01-01

Small isolated dune fields in the northern Mojave Desert are important centers of biodiversity and archaeological occupation sites. Currently dunes at Ash Meadows, Nevada, are stabilized by vegetation and are experiencing erosion of their upwind margins, indicating a negative sediment budget. New OSL ages from dunes at Ash Meadows indicate continuous eolian accumulation from 1.5 to 0.8 ka, with further accumulation around 0.2 ka. Prior studies (e.g., Mehringer and Warren, 1976) indicate periods of dune accumulation prior to 3.3 ka; 1.9–1 ka; and after 0.9 ka. These periods of eolian accumulation are largely synchronous with those identified elsewhere in the Mojave Desert. The composition of the Ash Meadows dunes indicates their derivation from regional fluvial sources, most likely during periods when axial washes were active as a result of enhanced winter precipitation.

Hydrometeor-enhanced tephra sedimentation: Constraints from the 18 May 1980 eruption of Mount St. Helens

USGS Publications Warehouse

Durant, A.J.; Rose, William I.; Sarna-Wojcicki, A. M.; Carey, Steven; Volentik, A.C.M.

2009-01-01

Uncertainty remains on the origin of distal mass deposition maxima observed in many recent tephra fall deposits. In this study the link between ash aggregation and the formation of distal mass deposition maxima is investigated through reanalysis of tephra fallout from the Mount St. Helens 18 May 1980 (MSH80) eruption. In addition, we collate all the data needed to model distal ash sedimentation from the MSH80 eruption cloud. Four particle size subpopulations were present in distal fallout with modes at 2.2 ??, 4.2 ??, 5.9 ??, and 8.3 ??. Settling rates of the coarsest subpopulation closely matched predicted single-particle terminal fall velocities. Sedimentation of particles <100 ??m was greatly enhanced, predominantly through aggregation of a particle subpopulation with modal diameter 5.9 ?? 0.2 ?? (19 ?? 3 ??m). Mammatus on the MSH80 cloud provided a mechanism to transport very fine ash particles, with predicted atmospheric lifetimes of days to weeks, from the upper troposphere to the surface in a matter of hours. In this mechanism, ash particles initiate ice hydrometeor formation high in the troposphere. Subsequently, the volcanic cloud rapidly subsides as mammatus develop from increased particle loading and cloud base sublimation. Rapid fallout occurs as the cloud passes through the melting level in a process analogous to snowflake aggregation. Aggregates sediment en masse and form the distal mass deposition maxima observed in many recent volcanic ash fall deposits. This work provides a data resource that will facilitate tephra sedimentation modeling and allow model intercomparisons. Copyright 2009 by the American Geophysical Union.

Strength Performance of Blended Ash Based Geopolymer Mortar

NASA Astrophysics Data System (ADS)

Zahib, Zaidahtulakmal M.; Kamaruddin, Kartini; Saman, Hamidah M.

2018-03-01

Geopolymer is a based on inorganic alumino-silicate binder system. Geopolymeric materials are formed using materials that containing silica and aluminium such as fly ash and rice husk ash, which activated by alkaline solution. This paper presents the study on the effect of replacement of SSA in RHA based geopolymer, types of curing and different molarity of NaOH used on the strength of Sewage Sludge Ash (SSA) and Rice Husk Ash (RHA) based geopolymer mortar incorporating with three (3) different mix proportions. Based geopolymer mortar was synthesized from treated sewage sludge and rice husk undergoing incineration process in producing ashes, activated with sodium silicate and sodium hydroxide solution by ratio of 2.5:1 and solution to ash ratio of 1:1. Molarity of 8M and 10M NaOH were used. The percentages of SSA replacement were 0%, 10% and 20% by weight. Compressive strength was conducted at age 7, 14 and 28 days to see the development of strength with two curing regimes, which are air curing and oven curing (60°C for 24 hours). From the research conducted, the ultimate compressive strength (6.28MPa) was obtained at zero replacement of SSA taken at 28 days of oven curing with 10M of NaOH. This shows that RHA, which is rich in silica content is enough to enhance the strength of geopolymer mortar especially with high molarity of NaOH.

Assessment of contamination by percolation of septic tank effluent through natural and amended soils.

PubMed

Cheung, K C; Venkitachalam, T H

2004-01-01

Fly ash has been found to be a potential material for the treatment of municipal and industrial wastewater, and may be useful in the treatment of septic tank effluent. Laboratory columns (30 cm) were used to determine the sorption capacity and hydraulic properties of lagoon fly ash, loamy sand, sand, and sand amended by lagoon fly ash (30 and 60%) and red mud gypsum (20%). The removal of chemical oxygen demand (COD) was high in all column effluents (71-93%). Extent of nitrification was high in Spearwood sand, Merribrook loamy sand and 20% red mud gypsum amended Spearwood sand. However, actual removal of nitrogen (N) was high in columns containing lagoon fly ash. Unamended Spearwood sand possessed only minimal capacity for P sorption. Merribrook loamy sand and red mud gypsum amended sand affected complete P removal throughout the study period of 12 weeks. Significant P leakage occurred from lagoon fly ash amended sand columns following 6-10 weeks of operation. Neither lagoon fly ash nor red mud gypsum caused any studied heavy metal contamination including manganese (Mn), lead (Pb), zinc (Zn), cadmium (Cd) and chromium (Cr) of effluent. It can be concluded that Merribrook loamy sand is better natural soil than Spearwood sand as a filter medium. The addition of lagoon fly ash enhanced the removal of P in Spearwood sand but the efficiency was lower than with red mud gypsum amendment.

Effect of laundry surfactants on surface charge and colloidal stability of silver nanoparticles.

PubMed

Skoglund, Sara; Lowe, Troy A; Hedberg, Jonas; Blomberg, Eva; Wallinder, Inger Odnevall; Wold, Susanna; Lundin, Maria

2013-07-16

The stability of silver nanoparticles (Ag NPs) potentially released from clothing during a laundry cycle and their interactions with laundry-relevant surfactants [anionic (LAS), cationic (DTAC), and nonionic (Berol)] have been investigated. Surface interactions between Ag NPs and surfactants influence their speciation and stability. In the absence of surfactants as well as in the presence of LAS, the negatively charged Ag NPs were stable in solution for more than 1 day. At low DTAC concentrations (≤1 mM), DTAC-Ag NP interactions resulted in charge neutralization and formation of agglomerates. The surface charge of the particles became positive at higher concentrations due to a bilayer type formation of DTAC that prevents from agglomeration due to repulsive electrostatic forces between the positively charged colloids. The adsorption of Berol was enhanced when above its critical micelle concentration (cmc). This resulted in a surface charge close to zero and subsequent agglomeration. Extended DLVO theory calculations were in compliance with observed findings. The stability of the Ag NPs was shown to depend on the charge and concentration of the adsorbed surfactants. Such knowledge is important as it may influence the subsequent transport of Ag NPs through different chemical transients and thus their potential bioavailability and toxicity.

The grinding behavior of ground copper powder for Cu/CNT nanocomposite fabrication by using the dry grinding process with a high-speed planetary ball mill

NASA Astrophysics Data System (ADS)

Choi, Heekyu; Bor, Amgalan; Sakuragi, Shiori; Lee, Jehyun; Lim, Hyung-Tae

2016-01-01

The behavior of ground copper powder for copper-carbon nanotube (copper-CNT) nanocomposite fabrication during high-speed planetary ball milling was investigated because the study of the behavior characteristics of copper powder has recently gained scientific interest. Also, studies of Cu/CNT composites have widely been done due to their useful applications to enhanced, advanced nano materials and components, which would significantly improve the properties of new mechatronics-integrated materials and components. This study varied experimental conditions such as the rotation speed and the grinding time with and without CNTs, and the particle size distribution, median diameter, crystal structure and size, and particle morphology were monitored for a given grinding time. We observed that pure copper powders agglomerated and that the morphology changed with changing rotation speed. The particle agglomerations were observed with maximum experiment conditions (700 rpm, 60 min) in this study of the grinding process for mechanical alloys in the case of pure copper powders because the grinding behavior of Cu/CNT agglomerations was affected by the addition of CNTs. Indeed, the powder morphology and the crystal size of the composite powder could be changed by increasing the grinding time and the rotation speed.

Single-step preparation and deagglomeration of itraconazole microflakes by supercritical antisolvent method for dissolution enhancement.

PubMed

Sathigari, Sateesh Kumar; Ober, Courtney A; Sanganwar, Ganesh P; Gupta, Ram B; Babu, R Jayachandra

2011-07-01

Itraconazole (ITZ) microflakes were produced by supercritical antisolvent (SAS) method and simultaneously mixed with pharmaceutical excipients in a single step to prevent drug agglomeration. Simultaneous ITZ particle formation and mixing with fast-flo lactose (FFL) was performed in a high-pressure stirred vessel at 116 bar and 40 °C by the SAS-drug excipient mixing (SAS-DEM) method. The effects of stabilizers, such as sodium dodecyl sulfate and poloxamer 407 (PLX), on particle formation and drug dissolution were studied. Drug-excipient formulations were characterized for surface morphology, crystallinity, drug-excipient interactions, drug content uniformity, and drug dissolution rate. Mixture of drug microflakes and FFL formed by the SAS-DEM process shows that the process was successful in overcoming drug-drug agglomeration. PLX produced crystalline drug flakes in loose agglomerates with superior dissolution and flow properties even at higher drug loadings. Characterization studies confirmed the crystallinity of the drug and absence of chemical interactions during the SAS process. The dissolution of ITZ was substantially higher due to SAS and SAS-DEM processes; this improvement can be attributed to the microflake particle structures, effective deagglomeration, and wetting of the drug flakes with the excipients. Copyright © 2011 Wiley-Liss, Inc. and the American Pharmacists Association

Designing of Multiphase Fly Ash/MWCNT/PU Composite Sheet Against Electromagnetic Environmental Pollution

NASA Astrophysics Data System (ADS)

Gujral, Parth; Varshney, Swati; Dhawan, S. K.

2016-06-01

Fly ash and multiwalled carbon nanotubes (MWCNT) reinforced multiphase polyurethane (PU) composite sheets have been fabricated by using a solution casting technique. Utilization of fly ash was the prime objective in order to reduce environmental pollution and to enhance the shielding properties of PU polymer. Our study proves that fly ash particles with MWCNTs in a PU matrix leads to novel hybrid high performance electromagnetic shielding interference material. Scanning electron microscopy confirms the existence of fly ash particles along with MWCNTs in a PU matrix. This multiphase composite shows total shielding effectiveness of 35.8 dB (>99.99% attenuation) in the Ku-band (12.4-18 GHz) frequency range. This is attributed to high dielectric losses of reinforcement present in the polymers matrix. The Nicolson-Ross-Weir algorithm has been applied to calculate the electromagnetic attributes and dielectric parameters of the PU samples by using scattering parameters ( S 11, S 22, S 12, S 21). The synthesized multiphase composites were further characterized by using x-ray diffraction, Fourier transform infrared spectroscopy, and thermo gravimetric analysis.

Biomass ash reutilisation as an additive in the composting process of organic fraction of municipal solid waste.

PubMed

Asquer, Carla; Cappai, Giovanna; De Gioannis, Giorgia; Muntoni, Aldo; Piredda, Martina; Spiga, Daniela

2017-11-01

In this work the effects of selected types of biomass ash on the composting process and final product quality were studied by conducting a 96-day long experiment where the source separated organic fraction of municipal waste, mixed with wood prunings that served as bulking agent, was added with 0%, 2%, 4% and 8% wt/wt of biomass ash. The evolution over time of the main process parameters was observed, and the final composts were characterised. On the basis of the results, both the composting process and the quality of the final product were improved by ash addition. Enhanced volatile solids reduction and biological stability (up to 32% and 52%, respectively, as compared to the unamended product) were attained when ash was added, since ash favored the aerobic degradation by acting asa physical conditioner. In the final products, higher humification of organic matter (expressed in terms of the humification index, that was 2.25 times higher in the most-enriched compost than in the unamended one) and total Ca, K, Mg and P content were observed when ash was used. The latter aspect may influence the composts marketability positively, particularly with regards to potassium and phosphorus. The heavy metals content, that is regarded as the main environmental disadvantage when using ash asa composting additive, did not negatively affect the final composts quality. However, some other controversial effects of ash, related to the moisture and temperature values attained during the process, pH (8.8-9.2 as compared to 8.2 of the unamended compost) and electrical conductivity levels (up to 53% higher as compared to the unamended compost) in the final composts, were also observed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Abundance of volatile organic compounds in white ash phloem and emerald ash borer larval frass does not attract Tetrastichus planipennisi in a Y-tube olfactometer.

PubMed

Chen, Yigen; Ulyshen, Michael D; Poland, Therese M

2016-10-01

Many natural enemies employ plant- and/or herbivore-derived signals for host/prey location. The larval parasitoid Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae) is 1 of 3 biocontrol agents currently being released in an effort to control the emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coloeptera: Burprestidae) in North America. To enhance its efficiency, allelochemicals that attract it need to be assessed. In this study, ash phloem volatile organic compounds (VOCs) of black, green, and white ash, and EAB larval frass were compared. Foraging behavior of T. planipennisi females in response to VOCs of white ash or frass from EAB larvae feeding on white ash phloem was tested using a Y-tube olfactometer. Results indicated that the 3 ash species had similar VOC profiles. EAB larval frass generally contained greater levels of VOCs than phloem. Factor analysis indicated that the 11 VOCs could be broadly divided into 2 groups, with α-bisabolol, β-caryophyllene, (E)-2-hexenal, (Z)-3-hexenal, limonene, methyl benzoate, methyl indole-3-acetic acid, methyl jasmonate, methyl salicylate as the first group and the rest (i.e., methyl linoleate and methyl linolenate) as a second. Abundance of VOCs in white ash phloem tissue and frass, nevertheless, did not attract T. planipennisi females. The concealed feeding of EAB larvae might explain the selection for detectable and reliable virbrational signals, instead of undetectable and relatively unreliable VOC cues from phloem and frass, in short-range foraging by T. planipennisi. Alternatively, it is possible that T. planipennisi is not amenable to the Y-tube olfactometer assay employed. © 2015 Institute of Zoology, Chinese Academy of Sciences.

Statistical prediction of nanoparticle delivery: from culture media to cell

NASA Astrophysics Data System (ADS)

Rowan Brown, M.; Hondow, Nicole; Brydson, Rik; Rees, Paul; Brown, Andrew P.; Summers, Huw D.

2015-04-01

The application of nanoparticles (NPs) within medicine is of great interest; their innate physicochemical characteristics provide the potential to enhance current technology, diagnostics and therapeutics. Recently a number of NP-based diagnostic and therapeutic agents have been developed for treatment of various diseases, where judicious surface functionalization is exploited to increase efficacy of administered therapeutic dose. However, quantification of heterogeneity associated with absolute dose of a nanotherapeutic (NP number), how this is trafficked across biological barriers has proven difficult to achieve. The main issue being the quantitative assessment of NP number at the spatial scale of the individual NP, data which is essential for the continued growth and development of the next generation of nanotherapeutics. Recent advances in sample preparation and the imaging fidelity of transmission electron microscopy (TEM) platforms provide information at the required spatial scale, where individual NPs can be individually identified. High spatial resolution however reduces the sample frequency and as a result dynamic biological features or processes become opaque. However, the combination of TEM data with appropriate probabilistic models provide a means to extract biophysical information that imaging alone cannot. Previously, we demonstrated that limited cell sampling via TEM can be statistically coupled to large population flow cytometry measurements to quantify exact NP dose. Here we extended this concept to link TEM measurements of NP agglomerates in cell culture media to that encapsulated within vesicles in human osteosarcoma cells. By construction and validation of a data-driven transfer function, we are able to investigate the dynamic properties of NP agglomeration through endocytosis. In particular, we statistically predict how NP agglomerates may traverse a biological barrier, detailing inter-agglomerate merging events providing the basis for predictive modelling of nanopharmacology.

Biomass fly ash incorporation in cement based materials =

NASA Astrophysics Data System (ADS)

Rajamma, Rejini

In recent years, pressures on global environment and energy security have led to an increasing demand on renewable energy sources, and diversification of Europe's energy supply. Among these resources the biomass could exert an important role, since it is considered a renewable and CO2 neutral energy resource once the consumption rate is lower than the growth rate, and can potentially provide energy for heat, power and transports from the same installation. Currently, most of the biomass ash produced in industrial plants is either disposed of in landfill or recycled on agricultural fields or forest, and most times this goes on without any form of control. However, considering that the disposal cost of biomass ashes are raising, and that biomass ash volumes are increasing worldwide, a sustainable ash management has to be established. The main objective of the present study is the effect of biomass fly ashes in cement mortars and concretes in order to be used as a supplementary cementitious material. The wastes analyzed in the study were collected from the fluidized bed boilers and grate boilers available in the thermal power plants and paper pulp plants situated in Portugal. The physical as well as chemical characterisations of the biomass fly ashes were investigated. The cement was replaced by the biomass fly ashes in 10, 20 and 30% (weight %) in order to investigate the fresh properties as well as the hardened properties of biomass fly ash incorporated cement mortar and concrete formulations. Expansion reactions such as alkali silica reaction (ASR), sulphate attack (external and internal) were conducted in order to check the durability of the biomass fly ash incorporated cement mortars and concretes. Alternative applications such as incorporation in lime mortars and alkali activation of the biomass fly ashes were also attempted. The biomass fly ash particles were irregular in shape and fine in nature. The chemical characterization revealed that the biomass fly ashes were similar to a class C fly ash. The mortar results showed a good scope for biomass fly ashes as supplementary cementitious materials in lower dosages (<20%). The poor workability, concerns about the organic content, alkalis, chlorides and sulphates stand as the reasons for preventing the use of biomass fly ash in high content in the cement mortars. The results obtained from the durability tests have shown a clear reduction in expansion for the biomass fly ash mortars/concretes and the binder blend made with biomass fly ash (20%) and metakaolin (10%) inhibited the ASR reaction effectively. The biomass fly ash incorporation in lime mortars did not improve the mortar properties significantly though the carbonation was enhanced in the 15-20% incorporation. The biomass fly ash metakaolin blend worked well in the alkali activated complex binder application also. Portland cement free binders (with 30-40 MPa compressive strength) were obtained on the alkali activation of biomass fly ashes (60-80%) blended with metakaolin (20-40%).

Effects of Al(OH)O nanoparticle agglomerate size in epoxy resin on tension, bending, and fracture properties

NASA Astrophysics Data System (ADS)

Jux, Maximilian; Finke, Benedikt; Mahrholz, Thorsten; Sinapius, Michael; Kwade, Arno; Schilde, Carsten

2017-04-01

Several epoxy Al(OH)O (boehmite) dispersions in an epoxy resin are produced in a kneader to study the mechanistic correlation between the nanoparticle size and mechanical properties of the prepared nanocomposites. The agglomerate size is set by a targeted variation in solid content and temperature during dispersion, resulting in a different level of stress intensity and thus a different final agglomerate size during the process. The suspension viscosity was used for the estimation of stress energy in laminar shear flow. Agglomerate size measurements are executed via dynamic light scattering to ensure the quality of the produced dispersions. Furthermore, various nanocomposite samples are prepared for three-point bending, tension, and fracture toughness tests. The screening of the size effect is executed with at least seven samples per agglomerate size and test method. The variation of solid content is found to be a reliable method to adjust the agglomerate size between 138-354 nm during dispersion. The size effect on the Young's modulus and the critical stress intensity is only marginal. Nevertheless, there is a statistically relevant trend showing a linear increase with a decrease in agglomerate size. In contrast, the size effect is more dominant to the sample's strain and stress at failure. Unlike microscaled agglomerates or particles, which lead to embrittlement of the composite material, nanoscaled agglomerates or particles cause the composite elongation to be nearly of the same level as the base material. The observed effect is valid for agglomerate sizes between 138-354 nm and a particle mass fraction of 10 wt%.

Hydrothermal solidification of municipal solid waste incineration bottom ash with slag addition.

PubMed

Jing, Zhenzi; Ran, Xianqiang; Jin, Fangming; Ishida, Emile H

2010-01-01

Hydrothermal solidification of municipal solid waste incineration (MSWI) bottom ash has been carried out under saturated steam pressure (1.56 MPa) at 200 degrees C for up to 24 h by mixing quartz, slaked lime and water-cooled blast furnace slag (WBFS). The strength enhancement for the WBFS addition was best. The strength development was shown to be due mainly to tobermorite formation, and the tobermorite formation densified matrix, thus promoting the strength development. WBFS seemed to have a higher reactivity than the quartz during the initial hydrothermal process, which provided more silica available to harden the solidified specimens. However, a longer curing time (24 h) was favorable to the quartz dissolution for tobermorite formation, which in turn, enhanced the strength for quartz addition. Curing time affected the crystal morphology evolution, and the stubby plate of tobermorite seemed to result in a high strength enhancement in this study. Laboratory leaching tests were conducted to determine the amount of heavy metals dissolved from the final solidified specimens, and the leaching results showed that after hydrothermal processing the heavy metals dissolved from the solidified specimens were reduced effectively. As such, the hydrothermal processing may have a high potential for recycling/reusing MSWI ash on a large scale. 2010 Elsevier Ltd. All rights reserved.

Biosurfactant from red ash trees enhances the bioremediation of PAH contaminated soil at a former gasworks site.

PubMed

Blyth, Warren; Shahsavari, Esmaeil; Morrison, Paul D; Ball, Andrew S

2015-10-01

Polycyclic aromatic hydrocarbons (PAHs) are persistent contaminants that accumulate in soil, sludge and on vegetation and are produced through activities such as coal burning, wood combustion and in the use of transport vehicles. Naturally occurring surfactants have been known to enhance PAH-removal from soil by improving PAH solubilization thereby increasing PAH-microbe interactions. The aim of this research was to determine if a biosurfactant derived from the leaves of the Australian red ash (Alphitonia excelsa) would enhance bioremediation of a heavily PAH-contaminated soil and to determine how the microbial community was affected. Results of GC-MS analysis show that the extracted biosurfactant was significantly more efficient than the control in regards to the degradation of total 16 US EPA priority PAHs (78.7% degradation compared to 62.0%) and total petroleum hydrocarbons (TPH) (92.9% degradation compared to 44.3%). Furthermore the quantification of bacterial genes by qPCR analysis showed that there was an increase in the number of gene copies associated with Gram positive PAH-degrading bacteria. The results suggest a commercial potential for the use of the Australian red ash tree as a source of biosurfactant for use in the accelerated degradation of hydrocarbons. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Ash that Closed Europe's Airspace in 2010

NASA Astrophysics Data System (ADS)

Gislason, S. R.; Alfredsson, H.; Olsson, J.; Eiriksdottir, E.; Oskarsson, N.; Hassenkam, T.; Nedel, S.; Bovet, N.; Hem, C.; Balogh, Z.; Dideriksen, K.; Stipp, S. L.

2011-12-01

On 14 April 2010, when meltwater from the Eyjafjallajökull glacier mixed with hot magma, an explosive phreato-magmatic eruption sent unusually fine-grained ash into the jet stream. It quickly dispersed over Europe. Previous airplane encounters with ash had caused sand blasted windows and particles melted inside jet engines, causing them to fail. Therefore, air traffic was grounded for several days. Concerns also arose about health risks from fallout, because ash can transport acids as well as toxic compounds. Studies on ash are usually made on material collected far from the source, where it could have mixed with other atmospheric particles, or after exposure to water as rain or fog, which would alter surface composition. In this study, a unique set of dry ash samples was collected during the explosive eruption and compared with fresh ash with the same bulk composition from a later more typical magmatic event, when meltwater did not have access to the magma.[1] Up to 70 mass % of the phreato-magmatic ash particles, collected 60 km from the source, was <60 μm in diameter, 22% was <10 μm and 11% was ≤ 4.4 μm. The finest grain size was found in the centre of the "collapsed" plume. The magmatic ash was coarser and its surface area was an order of magnitude smaller than for the explosive ash. The relative concentration of surface salts down to 10 nm depth was significantly lower on the explosive ash than the magmatic ash, because less volatile compounds were available to condense on the surfaces when water and steam were present. Instead, they dissolved in the meltwater and were transported as solutes in the ensuing floodwaters. The surface salts dissolved rapidly when exposed to experimental and natural waters, releasing pollutants and nutrients. Some of the salts further enhanced bulk dissolution of the ash. The particles of phreato-magmatic ash that reached Europe in the jet stream were especially sharp and hard, therefore abrasive, over their entire size range, from submillimeter to tens of nanometers. Edges remained sharp, even after 2 weeks of abrasion in stirred water suspensions. From the composition of the particles, we could predict that they would soften and melt at the temperatures typical of a jet engine (1500 to 2000 °C). [1] Gislason S.R. et al. (2011), PNAS, 108, 7307-7312

High concentration agglomerate dynamics at high temperatures.

PubMed

Heine, M C; Pratsinis, S E

2006-11-21

The dynamics of agglomerate aerosols are investigated at high solids concentrations that are typical in industrial scale manufacture of fine particles (precursor mole fraction larger than 10 mol %). In particular, formation and growth of fumed silica at such concentrations by chemical reaction, coagulation, and sintering is simulated at nonisothermal conditions and compared to limited experimental data and commercial product specifications. Using recent chemical kinetics for silica formation by SiCl4 hydrolysis and neglecting aerosol polydispersity, the evolution of the diameter of primary particles (specific surface area, SSA), hard- and soft-agglomerates, along with agglomerate effective volume fraction (volume occupied by agglomerate) is investigated. Classic Smoluchowski theory is fundamentally limited for description of soft-agglomerate Brownian coagulation at high solids concentrations. In fact, these high concentrations affect little the primary particle diameter (or SSA) but dominate the soft-agglomerate diameter, structure, and volume fraction, leading to gelation consistent with experimental data. This indicates that restructuring and fragmentation should affect product particle characteristics during high-temperature synthesis of nanostructured particles at high concentrations in aerosol flow reactors.

Multifrequency scanning probe microscopy study of nanodiamond agglomerates

NASA Astrophysics Data System (ADS)

Aravind, Vasudeva; Lippold, Stephen; Li, Qian; Strelcov, Evgheny; Okatan, Baris; Legum, Benjamin; Kalinin, Sergei; Clarion University Team; Oak Ridge National Laboratory Team

Due to their rich surface chemistry and excellent mechanical properties and non-toxic nature, nanodiamond particles have found applications such as biomedicine, tribology and lubrication, targeted drug delivery systems, tissue scaffolds and surgical implants. Although single nanodiamond particles have diameters about 4-5nm, they tend to form agglomerates. While these agglomerates can be useful for some purposes, many applications of nanodiamonds require single particle, disaggregated nanodiamonds. This work is oriented towards studying forces and interactions that contribute to agglomeration in nanodiamonds. In this work, using multifrequency scanning probe microscopy techniques, we show that agglomerate sizes can vary between 50-100nm in raw nanodiamonds. Extremeties of particles and Interfaces between agglomerates show dissipative forces with scanning probe microscope tip, indicating agglomerates could act as points of increased adhesion, thus reducing lubricating efficiency when nanodiamonds are used as lubricant additives. This research was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.

Characterising boiler ash from a circulating fluidised bed municipal solid waste incinerator and distribution of PCDD/F and PCB.

PubMed

Zhang, Mengmei; Buekens, Alfons; Li, Xiaodong

2018-05-31

In this study, ash samples were collected from five locations situated in the boiler of a circulating fluidised bed municipal solid waste incinerator (high- and low-temperature superheater, evaporator tubes and upper and lower economiser). These samples represent a huge range of flue gas temperatures and were characterised for their particle size distribution, surface characteristics, elemental composition, chemical forms of carbon and chlorine and distribution of polychlorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF) and biphenyls (PCB). Enrichment of chlorine, one of the main elements of organochlorinated pollutants, and copper, zinc and lead, major catalytic metals for dioxin-like compounds, was observed in lower-temperature ash deposits. The speciation of carbon and chlorine on ash surfaces was established, showing a positive correlation between organic chlorine and oxygen-containing carbon functional groups. The load of PCDD/F and PCB (especially dioxin-like PCB) tends to rise rapidly with falling temperature of flue gas, reaching their highest value in economiser ashes. The formation of PCDD/F congeners through the chlorophenol precursor route apparently was enhanced downstream the boiler. Principal component analysis (PCA) was applied to study the links between the ash characteristics and distribution of chloro-aromatics. The primary purpose of this study is improving the understanding of any links between the characteristics of ash from waste heat systems and its potential to form PCDD/F and PCB. The question is raised whether further characterisation of fly ash may assist to establish a diagnosis of poor plant operation, inclusive the generation, destruction and eventual emission of persistent organic pollutants (POPs).

Thermophysical Properties of Nanoparticle-Enhanced Ionic Liquids (NEILs) Heat-Transfer Fluids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fox, Elise B.; Visser, Ann E.; Bridges, Nicholas J.

2013-06-20

An experimental investigation was completed on nanoparticle enhanced ionic liquid heat transfer fluids as an alternative to conventional organic based heat transfer fluids (HTFs). These nanoparticle-based HTFs have the potential to deliver higher thermal conductivity than the base fluid without a significant increase in viscosity at elevated temperatures. The effect of nanoparticle morphology and chemistry on thermophysical properties was examined. Whisker shaped nanomaterials were found to have the largest thermal conductivity temperature dependence and were also less likely to agglomerate in the base fluid than spherical shaped nanomaterials.

Enhanced mechanical properties of graphene/copper nanocomposites using a molecular-level mixing process.

PubMed

Hwang, Jaewon; Yoon, Taeshik; Jin, Sung Hwan; Lee, Jinsup; Kim, Taek-Soo; Hong, Soon Hyung; Jeon, Seokwoo

2013-12-10

RGO flakes are homogeneously dispersed in a Cu matrix through a molecular-level mixing process. This novel fabrication process prevents the agglomeration of the RGO and enhances adhesion between the RGO and the Cu. The yield strength of the 2.5 vol% RGO/Cu nanocomposite is 1.8 times higher than that of pure Cu. The strengthening mechanism of the RGO is investigated by a double cantilever beam test using the graphene/Cu model structure. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Stimulation of methane oxidation potential and effects on vegetation growth by bottom ash addition in a landfill final evapotranspiration cover.

PubMed

Kim, Gil Won; Ho, Adrian; Kim, Pil Joo; Kim, Sang Yoon

2016-09-01

The landfilling of municipal solid waste is a significant source of atmospheric methane (CH4), contributing up to 20% of total anthropogenic CH4 emissions. The evapotranspiration (ET) cover system, an alternative final cover system in waste landfills, has been considered to be a promising way to mitigate CH4 emissions, as well as to prevent water infiltration using vegetation on landfill cover soils. In our previous studies, bottom ash from coal-fired power plants was selected among several industrial residues (blast furnace slag, bottom ash, construction waste, steel manufacture slag, stone powder sludge, and waste gypsum) as the best additive for ET cover systems, with the highest mechanical performance achieved for a 35% (wtwt(-1)) bottom ash content in soil. In this study, to evaluate the field applicability of bottom ash mixed soil as ET cover, four sets of lysimeters (height 1.2m×width 2m×length 6m) were constructed in 2007, and four different treatments were installed: (i) soil+bottom ash (35% wtwt(-1)) (SB); (ii) soil+compost (2% wtwt(-1), approximately corresponding to 40Mgha(-1) in arable field scale) (SC); (iii) soil+bottom ash+compost (SBC); and (iv) soil only as the control (S). The effects of bottom ash mixing in ET cover soil on CH4 oxidation potential and vegetation growth were evaluated in a pilot ET cover system in the 5th year after installation by pilot experiments using the treatments. Our results showed that soil properties were significantly improved by bottom ash mixing, resulting in higher plant growth. Bottom ash addition significantly increased the CH4 oxidation potential of the ET cover soil, mainly due to improved organic matter and available copper concentration, enhancing methanotrophic abundances in soil amended with bottom ash. Conclusively, bottom ash could be a good alternative as a soil additive in the ET cover system to improve vegetation growth and mitigate CH4 emission impact in the waste landfill system. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pulse combusted acoustic agglomeration apparatus and process

DOEpatents

Mansour, Momtaz N.

1993-01-01

An improved apparatus and process for removal of particulates entrained in a gas stream are provided. The removal process employs a pulse combustor to provide an acoustic pressure wave to acoustically enhance bimodal agglomeration of particulates which may be collected and removed using a conventional separation apparatus. A particulate having a size different from the size of the particulate in the gas stream to be cleaned is introduced into the system to effectuate the bimodal process. The apparatus may be employed as a direct fired system for improved operation of gas-operated equipment such as a gas turbine, or may, alternatively, be employed as an add-on subsystem for combustion exhaust clean-up. Additionally, the added particulate may be a sorbent for effecting sorption of other contaminants such as sulfur. Various other particulates for contaminant removal may also be introduced into the system as exemplified by alkali-gettering agents.

Moving granular-bed filter development program, Option III: Development of moving granular-bed filter technology for multi-contaminant control. Task 14: Test plan; Topical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haas, J.C.; Olivo, C.A.; Wilson, K.B.

1994-04-01

An experimental test plan has been prepared for DOE/METC review and approval to develop a filter media suitable for multi-contaminant control in granular-bed filter (GBF) applications. The plan includes identification, development, and demonstration of methods for enhanced media morphology, chemical reactivity, and mechanical strength. The test plan includes media preparation methods, physical and chemical characterization methods for fresh and reacted media, media evaluation criteria, details of test and analytical equipment, and test matrix of the proposed media testing. A filter media composed of agglomerated limestone and clay was determined to be the best candidate for multi-contaminate control in GBF operation.more » The combined limestone/clay agglomerate has the potential to remove sulfur and alkali species, in addition to particulate, and possibly halogens and trace heavy metals from coal process streams.« less

Multiple seeding for the growth of bulk GdBCO-Ag superconductors with single grain behaviour

NASA Astrophysics Data System (ADS)

Shi, Y.; Durrell, J. H.; Dennis, A. R.; Huang, K.; Namburi, D. K.; Zhou, D.; Cardwell, D. A.

2017-01-01

Rare earth-barium-copper oxide bulk superconductors fabricated in large or complicated geometries are required for a variety of engineering applications. Initiating crystal growth from multiple seeds reduces the time taken to melt-process individual samples and can reduce the problem of poor crystal texture away from the seed. Grain boundaries between regions of independent crystal growth can reduce significantly the flow of current due to crystallographic misalignment and the agglomeration of impurity phases. Enhanced supercurrent flow at such boundaries has been achieved by minimising the depth of the boundary between A growth sectors generated during the melt growth process by reducing second phase agglomerations and by a new technique for initiating crystal growth that minimises the misalignment between different growth regions. The trapped magnetic fields measured for the resulting samples exhibit a single trapped field peak indicating they are equivalent to conventional single grains.

Ash storms: impacts of wind-remobilised volcanic ash on rural communities and agriculture following the 1991 Hudson eruption, southern Patagonia, Chile

NASA Astrophysics Data System (ADS)

Wilson, T. M.; Cole, J. W.; Stewart, C.; Cronin, S. J.; Johnston, D. M.

2011-04-01

Tephra fall from the August 1991 eruption of Volcán Hudson affected some 100,000 km2 of Patagonia and was almost immediately reworked by strong winds, creating billowing clouds of remobilised ash, or `ash storms'. The immediate impacts on agriculture and rural communities were severe, but were then greatly exacerbated by continuing ash storms. This paper describes the findings of a 3-week study tour of the diverse environments of southern Patagonia affected by ash storms, with an emphasis on determining the impacts of repeated ash storms on agriculture and local practices that were developed in an attempt to mitigate these impacts. Ash storms produce similar effects to initial tephra eruptions, prolonged for considerable periods. These have included the burial of farmland under dune deposits, abrasion of vegetation and contamination of feed supplies with fine ash. These impacts can then cause problems for grazing animals such as starvation, severe tooth abrasion, gastrointestinal problems, corneal abrasion and blindness, and exhaustion if sheep fleeces become laden with ash. In addition, ash storms have led to exacerbated soil erosion, human health impacts, increased cleanup requirements, sedimentation in irrigation canals, and disruption of aviation and land transport. Ash deposits were naturally stabilised most rapidly in areas with high rainfall (>1,500 mm/year) through compaction and enhanced vegetation growth. Stabilisation was slowest in windy, semi-arid regions. Destruction of vegetation and suppression of regrowth by heavy tephra fall (>100 mm) hindered the stabilisation of deposits for years, and reduced the surface friction which increased wind erosivity. Stabilisation of tephra deposits was improved by intensive tillage, use of windbreaks and where there was dense and taller vegetative cover. Long-term drought and the impracticality of mixing ash deposits with soil by tillage on large farms was a barrier to stabilising deposits and, in turn, agricultural recovery. The continuing ash storms motivated the partial evacuation of small rural towns such as Chile Chico (Chile) and Los Antiguos (Argentina) in September-December 1991, after the primary tephra fall in August 1991. Greatly increased municipal cleanup efforts had to be sustained beyond the initial tephra fall to cope with the ongoing impacts of ash storms. Throughout the 1990s, ash storms contributed to continued population migration out of the affected area, leaving hundreds of farms abandoned on the Argentine steppe. The major lesson from our study is the importance of stabilisation of ash deposits as soon as possible after the initial eruption, particularly in windy, arid climates. Suggested mitigation measures include deep cultivation of the ash into the soil and erecting windbreaks.

Method for recovering light hydrocarbons from coal agglomerates

DOEpatents

Huettenhain, Horst; Benz, August D.; Getsoian, John

1991-01-01

A method and apparatus for removing light hydrocarbons, such as heptane, from coal agglomerates includes an enclosed chamber having a substantially horizontal perforate surface therein. The coal agglomerates are introduced into a water bath within the chamber. The agglomerates are advanced over the surface while steam is substantially continuously introduced through the surface into the water bath. Steam heats the water and causes volatilization of the light hydrocarbons, which may be collected from the overhead of the chamber. The resulting agglomerates may be collected at the opposite end from the surface and subjected to final draining processes prior to transportation or use.

Agglomerates, smoke oxide particles, and carbon inclusions in condensed combustion products of an aluminized GAP-based propellant

NASA Astrophysics Data System (ADS)

Ao, Wen; Liu, Peijin; Yang, Wenjing

2016-12-01

In solid propellants, aluminum is widely used to improve the performance, however the condensed combustion products especially the large agglomerates generated from aluminum combustion significantly affect the combustion and internal flow inside the solid rocket motor. To clarify the properties of the condensed combustion products of aluminized propellants, a constant-pressure quench vessel was adopted to collect the combustion products. The morphology and chemical compositions of the collected products, were then studied by using scanning electron microscopy coupled with energy dispersive (SEM-EDS) method. Various structures have been observed in the condensed combustion products. Apart from the typical agglomerates or smoke oxide particles observed before, new structures including the smoke oxide clusters, irregular agglomerates and carbon-inclusions are discovered and investigated. Smoke oxide particles have the highest amount in the products. The highly dispersed oxide particle is spherical with very smooth surface and is on the order of 1-2 μm, but due to the high temperature and long residence time, these small particles will aggregate into smoke oxide clusters which are much larger than the initial particles. Three types of spherical agglomerates have been found. As the ambient gas temperature is much higher than the boiling point of Al2O3, the condensation layer inside which the aluminum drop is burning would evaporate quickly, which result in the fact that few "hollow agglomerates" has been found compared to "cap agglomerates" and "solid agglomerates". Irregular agglomerates usually larger than spherical agglomerates. The formation of irregular agglomerates likely happens by three stages: deformation of spherical aluminum drops; combination of particles with various shape; finally production of irregular agglomerates. EDS results show the ratio of O to Al on the surface of agglomerates is lower in comparison to smoke oxide particles. C and O account for most element compositions for all the carbon inclusions. The rough, spherical, strip shape and flake shape carbon-inclusions are believed to be derived from the degradation products of the binder or oxidizer, while the fiber silk is possibly the combustion product of fiber inside the heat insulation layer of the propellants. Images of products at different pressures reveal high pressure reduces the degree of agglomeration. The chemical compositions, size range and content of all the observed structures are given in this paper. Results of our study are expected to provide better insight in the working process of solid rocket motor.

Mechanical characterization of Al-2024 reinforced with fly ash and E-glass by stir casting method

NASA Astrophysics Data System (ADS)

Ramesh, B. T.; Swamy, R. P.; Vinayak, Koppad

2018-04-01

The properties of MMCs enhance their handling in automotive and various applications for the reason that of encouraging properties of high stiffness and high strength, low density, high electrical and thermal conductivity, corrosion resistance, improved wear resistance etc. Metal Matrix Composites are a vital family of materials designed at achieving an improved combination of properties. Our paper deals through to fabricate Hybrid Composite by heating Al 2024 in furnace at a temperature of around 4000 C. E-Glass fiber & Fly ash will be added to the molten metal with changing weight fractions and stirred strongly. Then the ensuing composition will poured into the mould to obtain hybrid composite casting. Aluminium alloy (2024) is the matrix metal used in the present investigation. Fly ash and e-glass are used as the reinforced materials to produce the composite by stir casting. Fly ash is selected because of it is less expensive and low density reinforcement available in great quantities as solid disposal from thermal power plants. The Test specimen is prepared as per ASTM standards size by machining operations to conduct Tensile, Compression, Hardness, and wear test. The test specimens are furnished for tensile, compression strength and wear as per ASTM standard E8, E9 and G99 respectively using Universal Testing Machine and pin on disk machine. It is seen that the fabricated MMC obtained has got enhanced mechanical strength.

Low-reactive circulating fluidized bed combustion (CFBC) fly ashes as source material for geopolymer synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu Hui; Li Qin; Shen Lifeng

2010-01-15

In this contribution, low-reactive circulating fluidized bed combustion (CFBC) fly ashes (CFAs) have firstly been utilized as a source material for geopolymer synthesis. An alkali fusion process was employed to promote the dissolution of Si and Al species from the CFAs, and thus to enhance the reactivity of the ashes. A high-reactive metakaolin (MK) was also used to consume the excess alkali needed for the fusion. Reactivities of the CFAs and MK were examined by a series of dissolution tests in sodium hydroxide solutions. Geopolymer samples were prepared by alkali activation of the source materials using a sodium silicate solutionmore » as the activator. The synthesized products were characterized by mechanical testing, scanning electron microscopy (SEM), X-ray diffractography (XRD), as well as Fourier transform infrared spectroscopy (FTIR). The results of this study indicate that, via enhancing the reactivity by alkali fusion and balancing the Na/Al ratio by additional aluminosilicate source, low-reactive CFAs could also be recycled as an alternative source material for geopolymer production.« less

Novel Binders and Methods for Agglomeration of Ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. K. Kawatra; T. C. Eisele; K. A. Lewandowski

2006-09-30

Heap leaching is one of the methods being used to recover metal from low grade ore deposits. The main problem faced during heap leaching is the migration of fine grained particles through the heap, forming impermeable beds which result in poor solution flow. The poor solution flow leads to less contact between the leach solution and the ore, resulting in low recovery rates. Agglomeration of ore into coarse, porous masses prevents fine particles from migrating and clogging the spaces and channels between the larger ore particles. Currently, there is one facility in the United States which uses agglomeration. This operationmore » agglomerates their ore using leach solution (raffinate), but is still experiencing undesirable metal recovery from the heaps due to agglomerate breakdown. The use of a binder, in addition to the leach solution, during agglomeration would help to produce stronger agglomerates that did not break down during processing. However, there are no known binders that will work satisfactorily in the acidic environment of a heap, at a reasonable cost. As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. Increasing copper recovery in heap leaching by the use of binders and agglomeration would result in a significant decrease in the amount of energy consumed. Assuming that 70% of all the leaching heaps would convert to using agglomeration technology, as much as 1.64*10{sup 12} BTU per year would be able to be saved if a 25% increase in copper recovery was experienced, which is equivalent to saving approximately 18% of the energy currently being used in leaching heaps. For every week a leach cycle was decreased, a savings of as much as 1.23*10{sup 11} BTU per week would result. This project has identified several acid-resistant binders and agglomeration procedures. These binders and experimental procedures will be able to be used for use in improving the energy efficiency of heap leaching.« less

Effective use of fly ash slurry as fill material.

PubMed

Horiuchi, S; Kawaguchi, M; Yasuhara, K

2000-09-15

A lot of effort has been put into increasing coal ash utilization; however, 50% of total amount is disposed of on land and in the sea. Several attempts have been reported recently concerning slurried coal fly ash use for civil engineering materials, such as for structural fill and backfill. The authors have studied this issue for more than 15 years and reported its potential for (1) underwater fills, (2) light weight backfills, and (3) light weight structural fills, through both laboratory tests and construction works. This paper is an overview of the results obtained for slurry, focusing on the following. (1) Coal fly ash reclaimed by slurry placement shows lower compressibility, higher ground density, and higher strength than by the other methods. This higher strength increases stability against liquefaction during earthquake. (2) Higher stability of the fly ash ground formed by slurry placement is caused by higher density and its self-hardening property. (3) Stability of fly ash reclaimed ground can be increased by increasing density and also by strength enhancement by cement addition. (4) Technical data obtained through a man-made island construction project shows the advantages of fly ash slurry in terms of mechanical properties such as higher stability against sliding failure, sufficient ground strength, and also in terms of cost saving. (5) Concentration in leachates from the placed slurry is lower than the Japanese environmental law. (6) In order to enlarge the fly ash slurry application toward a lightweight fill, mixtures of air foam, cement and fly ash were examined. Test results shows sufficient durability of this material against creep failure. This material was then used as lightweight structural fill around a high-rise building, and showed sufficient quality. From the above data, it can be concluded that coal fly ash slurry can be effectively utilized in civil engineering projects.

Fragmentation and bond strength of airborne diesel soot agglomerates

PubMed Central

Rothenbacher, Sonja; Messerer, Armin; Kasper, Gerhard

2008-01-01

Background The potential of diesel soot aerosol particles to break up into smaller units under mechanical stress was investigated by a direct impaction technique which measures the degree of fragmentation of individual agglomerates vs. impact energy. Diesel aerosol was generated by an idling diesel engine used for passenger vehicles. Both the aerosol emitted directly and aerosol that had undergone additional growth by Brownian coagulation ("aging") was investigated. Optionally a thermo-desoption technique at 280°C was used to remove all high-volatility and the majority of low-volatility HC adsorbates from the aerosol before aging. Results It was found that the primary soot agglomerates emitted directly from the engine could not be fragmented at all. Soot agglomerates permitted to grow additionally by Brownian coagulation of the primary emitted particles could be fragmented to a maximum of 75% and 60% respectively, depending on whether adsorbates were removed from their surface prior to aging or not. At most, these aged agglomerates could be broken down to roughly the size of the agglomerates from the primary emission. The energy required for a 50% fragmentation probability of all bonds within an agglomerate was reduced by roughly a factor of 2 when aging "dry" agglomerates. Average bond energies derived from the data were 0.52*10-16 and 1.2*10-16 J, respectively. This is about 2 orders of magnitude higher than estimates for pure van-der-Waals agglomerates, but agrees quite well with other observations. Conclusion Although direct conclusions regarding the behavior of inhaled diesel aerosol in contact with body fluids cannot be drawn from such measurements, the results imply that highly agglomerated soot aerosol particles are unlikely to break up into units smaller than roughly the size distribution emitted as tail pipe soot. PMID:18533015

Physiological and behavioral responses of an arboreal mammal to smoke and charcoal-ash substrate.

PubMed

Nowack, Julia; Stawski, Clare; Körtner, Gerhard; Geiser, Fritz

2018-02-01

The recent observation that torpor plays a key role in post-fire survival has been mainly attributed to the reduced food resources after fires. However, some of these adjustments can be facilitated or amplified by environmental changes associated with fires, such as the presence of a charcoal-ash substrate. In a previous experiment on a small terrestrial mammal the presence of charcoal and ash linked to food restriction intensified torpor use. However, whether fire cues also act as a trigger of torpor use when food is available and whether they affect other species including arboreal mammals remains elusive. To evaluate whether smoke, charcoal and ash can act as proximate triggers for an impending period of food shortage requiring torpor for mammals, we conducted an experiment on captive sugar gliders (Petaurus breviceps), a small, arboreal marsupial, housed in outside aviaries under different food regimes and natural ambient conditions. When food was available, fire simulation via exposure to smoke and charcoal-ash substrate caused a significant earlier start of activity and a significant decrease in resting body temperature. In contrast, only when food was withheld, did smoke and charcoal-ash exposure significantly enhance torpor depth and duration. Thus, our study not only provides evidence that fire simulation does affect arboreal and terrestrial species similarly, but also suggests that smoke and ash were presumably selected as cues for torpor induction because they indicate an impending lack of food. Copyright © 2017 Elsevier Inc. All rights reserved.

Problems of Research, Projects and Mechanisms for Their Implementation in Chelyabinsk City Agglomeration

NASA Astrophysics Data System (ADS)

Bolshakov, V. V.

2017-11-01

The article analyzes the research and design methods of urban agglomerations in the context of the Chelyabinsk agglomeration from the point of view of correctness, objectivity and consistency of the results obtained. The completed and approved project of the Chelyabinsk agglomeration is analysed to provide architectural and planning solutions for sustainable social and economic development according to the theories that have been formed to date. The possibility of effectuation and implementation of the approved project of the Chelyabinsk agglomeration taking in account existing specific natural, historical and socio-economic factors characteristic for the territory under consideration is examined. The authors draw the conclusions the project of the Chelyabinsk agglomeration has been developed in line with the town-planning solutions that do not reflect modern approaches based on the competitive advantages of territories and do not form a space providing transition to a modernized and innovative economy. Specific town-planning decisions have a weak justification and an undeveloped methodology for pre-project analysis and methodology for designing urban agglomerations because of absence of a full study of the phenomenon of urban agglomeration and processes occurring in it today. It is necessary to continue research in the field of development of the Chelyabinsk agglomeration with the use of a logical and objective methodology to analyze the territory and design which can lead to the formation of an urban-planning information model that reflects all the system processes and allows for predicting project solutions.

Growth and form of planetary seedlings: results from a sounding rocket microgravity aggregation experiment.

PubMed

Krause, Maya; Blum, Jürgen

2004-07-09

In a second microgravity experiment on the formation of dust agglomerates by Brownian motion-induced collisions we find that the agglomerates have fractal dimensions as low as 1.4. Because of much better data, we are now able to derive the diffusion constant of the agglomerates as a function of mass, to show that a power law with an exponent of 1.7 describes the temporal evolution of the mean agglomerate mass very well and to prove that the collision cross section is proportional to the geometrical cross section. In addition to that we derived the universal mass-distribution function of the agglomerates.

Development and Application of Agglomerated Multigrid Methods for Complex Geometries

NASA Technical Reports Server (NTRS)

Nishikawa, Hiroaki; Diskin, Boris; Thomas, James L.

2010-01-01

We report progress in the development of agglomerated multigrid techniques for fully un- structured grids in three dimensions, building upon two previous studies focused on efficiently solving a model diffusion equation. We demonstrate a robust fully-coarsened agglomerated multigrid technique for 3D complex geometries, incorporating the following key developments: consistent and stable coarse-grid discretizations, a hierarchical agglomeration scheme, and line-agglomeration/relaxation using prismatic-cell discretizations in the highly-stretched grid regions. A signi cant speed-up in computer time is demonstrated for a model diffusion problem, the Euler equations, and the Reynolds-averaged Navier-Stokes equations for 3D realistic complex geometries.

Communication — Modeling polymer-electrolyte fuel-cell agglomerates with double-trap kinetics

DOE PAGES

Pant, Lalit M.; Weber, Adam Z.

2017-04-14

A new semi-analytical agglomerate model is presented for polymer-electrolyte fuel-cell cathodes. The model uses double-trap kinetics for the oxygen-reduction reaction, which can capture the observed potential-dependent coverage and Tafel-slope changes. An iterative semi-analytical approach is used to obtain reaction rate constants from the double-trap kinetics, oxygen concentration at the agglomerate surface, and overall agglomerate reaction rate. The analytical method can predict reaction rates within 2% of the numerically simulated values for a wide range of oxygen concentrations, overpotentials, and agglomerate sizes, while saving simulation time compared to a fully numerical approach.

Toward an integrated Volcanic Ash Observing System in Europe

NASA Astrophysics Data System (ADS)

Lee, Deborah; Lisk, Ian

2014-05-01

Volcanic ash from the Icelandic eruption of Eyjafjallajökull in April and May of 2010 resulted in the decision by many northern European countries to impose significant restrictions on the use of their airspace. The eruption, extent and persistence of the ash revealed how reliant society now is on a safe and efficient air transport system and the fragility of that system when affected by the impact of complex natural hazards. As part of an EC framework programme, the 2011-2013 WEZARD (WEather HaZARD for aeronautics) consortium conducted a cross-industry volcanic ash capability and gap analyses, with the EUMETNET (network of 29 National Meteorological Services) led Work Package 3 focussing on a review of observational and monitoring capabilities, atmospheric dispersion modelling and data exchange. The review has revealed a patchwork of independent observing capabilities for volcanic ash, with some countries investing and others not at all, and most existing networks focus on space-based products. Existing capabilities do not provide the necessary detail on the geographical and vertical extent of volcanic ash and associated levels of contamination, which decision makers in the aviation industry require in order to decide where it is safe to fly. A resultant high priority was identified by WEZARD Work Package 3 for an enhanced observational network of complementary monitoring systems needed to initialise, validate and verify volcanic ash dispersion model output and forecasts. Thus a key recommendation is to invest in a major pre-operational demonstrator "European volcanic ash observing network", focussing on distal monitoring, and aiming to a) fill R&D gaps identified in instrumentation and algorithms and b) integrate data, where possible in near-real-time, from a range of ground-based, airborne and space-based techniques. Here we present a key WEZARD recommendation toward an integrated volcanic ash observing system in Europe, in context with other related projects and initiatives. We will also look to highlight the work underway by VAACs (Volcanic Ash Advisory Centres) and aviation regulatory authorities within the IAVWOPSG (International Airways Volcano Watch Operations Group) to develop the 'agreed in situ and/or remote sensing techniques' that underpin the newly approved definition of 'Discernible ash'.

The Magnet Cove Rutile Company mine, Hot Spring County, Arkansas

USGS Publications Warehouse

Kinney, Douglas M.

1949-01-01

The Magnet Cove Rutile Company mine was mapped by the U.S. Geological Survey in November 1944. The pits are on the northern edge of Magnet Cove and have been excavated in the oxidized zone of highly weathered and altered volcanic agglomerate. The agglomerate is composed of altered mafic igneous rocks in a matrix of white to gray clay, a highly altered tuff. The agglomerate appears layered and is composed of tuffaceous clay material below and igneous blocks above. The agglomerate is cut by aplite and lamprophyre dikes. Alkalic syenite dikes crop out on the ridge north of the pits. At the present stage of mine development the rutile seems to be concentrated in a narrow zone beneath the igneous blocks of the agglomerate. Rutile, associated with calcite and pyrite, occurs as disseminated acicular crystals and discontinuous vein-like masses in the altered tuff. Thin veins of rutile locally penetrate the mafic igneous blocks of the agglomerate.

Coal fly ash-slag-based geopolymers: microstructure and metal leaching.

PubMed

Izquierdo, Maria; Querol, Xavier; Davidovits, Joseph; Antenucci, Diano; Nugteren, Henk; Fernández-Pereira, Constantino

2009-07-15

This study deals with the use of fly ash as a starting material for geopolymeric matrices. The leachable concentrations of geopolymers were compared with those of the starting fly ash to evaluate the retention of potentially harmful elements within the geopolymer matrix. Geopolymer matrices give rise to a leaching scenario characterised by a highly alkaline environment, which inhibits the leaching of heavy metals but may enhance the mobilization of certain oxyanionic species. Thus, fly ash-based geopolymers were found to immobilize a number of trace pollutants such as Be, Bi, Cd, Co, Cr, Cu, Nb, Ni, Pb, Sn, Th, U, Y, Zr and rare earth elements. However, the leachable levels of elements occurring in their oxyanionic form such as As, B, Mo, Se, V and W were increased after geopolymerization. This suggests that an optimal dosage, synthesis and curing conditions are essential in order to obtain a long-term stable final product that ensures an efficient physical encapsulation.

Pervious concrete using fly ash aggregate as coarse aggregate-an experimental study

NASA Astrophysics Data System (ADS)

Dash, Subhakanta; Kar, Biswabandita; Mukherjee, Partha Sarathi

2018-05-01

The present study deals with the fabrication of pervious concrete from fly ash aggregates. The pervious concrete were obtained by the mixture of three different size fly ash aggregates (4.75 mm,9.5 mm,12.5 mm), Portland cement, water with little amount of sand or without sand. Admixtures like Silica fume(SF) and Super plasticizer are added to the mixture to enhance the strength of concrete. Trial being taken on preparation of Fly ash based pervious concrete (FPC) with different w/c ratio i.e. 0.30, 0.35 and 0.40 respectively. Tests such as porosity, permeability and compressive, strength are studied for this concrete material and the result concluded that the concrete when cured for 28 days its compressive strength falls in between 7.15 - 15.74 MPa and permeability 9.38 - 16.07 mm/s with porosity 27.59 - 34.05% and these are suited to be used as for use as an environment friendly concrete.

Thermal and hydrometallurgical recovery methods of heavy metals from municipal solid waste fly ash

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuboňová, L., E-mail: lenka.kubonova@vsb.cz; Langová, Š.; Nowak, B.

2013-11-15

Highlights: • MSW fly ash was thermally and hydrometallurgically treated to remove heavy metals. • More than 90% of easy volatile heavy metals (Cd and Pb) were removed thermally. • More than 90% of Cd, Cr, Cu an Zn were removed by alkaline – acid leaching. • The best results were obtained for the solution of 3 M NaOH and 2 M H{sub 2}SO{sub 4}. - Abstract: Heavy metals in fly ash from municipal solid waste incinerators are present in high concentrations. Therefore fly ash must be treated as a hazardous material. On the other hand, it may be amore » potential source of heavy metals. Zinc, lead, cadmium, and copper can be relatively easily removed during the thermal treatment of fly ash, e.g. in the form of chlorides. In return, wet extraction methods could provide promising results for these elements including chromium and nickel. The aim of this study was to investigate and compare thermal and hydrometallurgical treatment of municipal solid waste fly ash. Thermal treatment of fly ash was performed in a rotary reactor at temperatures between 950 and 1050 °C and in a muffle oven at temperatures from 500 to 1200 °C. The removal more than 90% was reached by easy volatile heavy metals such as cadmium and lead and also by copper, however at higher temperature in the muffle oven. The alkaline (sodium hydroxide) and acid (sulphuric acid) leaching of the fly ash was carried out while the influence of temperature, time, concentration, and liquid/solid ratio were investigated. The combination of alkaline-acidic leaching enhanced the removal of, namely, zinc, chromium and nickel.« less

Composite propellant combustion with low aluminum agglomeration

NASA Astrophysics Data System (ADS)

Mullen, Jessica Christine

Aluminum behavior---accumulation, agglomeration and ignition---is studied in a unique, wide-distribution, ammonium perchlorate/hydroxyl-terminated polybutadiene (AP/HTPB) propellant formulation that results in low Al agglomeration, even at low pressures (1--30 atm). Variations in formulation---such as fine-AP/binder ratio, Al particle size, Al loading, coarse-AP size---are also examined. A fuel-rich, oxygenated binder matrix highly loaded with fine (2-mum) AP (FAP) at 75/25:FAP/binder (by mass) is found to have premixed flame conditions that produce minimal agglomeration (without ignition) of 15-mum Al. Coarse AP (CAP) is added to the system in the form of either particles (200 or 400 mum) or pressed-AP laminates (simulated CAP). In the 2-D laminate system the CAP/oxyfuel-matrix flame structure is seen to be similar to that previously described for non-aluminized laminates with split (diffusion) and merged (partially-premixed) flame regimes, depending on pressure and fuel-matrix thickness. Both laminate and particulate systems show that with CAP present, Al can agglomerate more extensively on CAP via lateral surface migration from fuel matrix to the CAP region. The particulate CAP system also shows that Al can accumulate/agglomerate via settling on CAP from above (in the direction of burning). Both systems, but more clearly the 2-D laminates, show that with CAP present, Al is ignited by the outer CAP/fuel-matrix canopy flames. Thus, a propellant formulation is proposed for reducing overall Al agglomeration through intrinsically reduced agglomeration in the fuel-matrix and a reduced number of CAP-particle agglomerates via higher FAP/CAP ratio.

Recycling of MSWI fly ash by means of cementitious double step cold bonding pelletization: Technological assessment for the production of lightweight artificial aggregates.

PubMed

Colangelo, Francesco; Messina, Francesco; Cioffi, Raffaele

2015-12-15

In this work, an extensive study on the recycling of municipal solid waste incinerator fly ash by means of cold bonding pelletization is presented. The ash comes from an incineration plant equipped with rotary and stoker furnaces, in which municipal, hospital and industrial wastes are treated. Fly ash from waste incineration is classified as hazardous and cannot be utilized or even landfilled without prior treatment. The pelletization process uses cement, lime and coal fly ash as components of the binding systems. This process has been applied to several mixes in which the ash content has been varied from 50% (wt.%) up to a maximum of 70%. An innovative additional pelletization step with only cementitious binder has been performed in order to achieve satisfactory immobilization levels. The obtained lightweight porous aggregates are mostly suitable for recovery in the field of building materials with enhanced sustainability properties. Density, water absorption and crushing strength ranged from 1000 to 1600 kg/m(3), 7 to 16% and 1.3 to 6.2 MPa, respectively, and the second pelletization step increased stabilization efficiency. The feasibility of the process has been analyzed by testing also concrete specimens containing the artificial aggregates, resulting in lightweight concrete of average performance. Copyright © 2015 Elsevier B.V. All rights reserved.

Oxidation characteristics of gasoline direct-injection (GDI) engine soot: Catalytic effects of ash and modified kinetic correlation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Seungmok; Seong, Heeje

In this paper, experimental analyses are conducted into the GDI soot oxidation characteristics as dependent on engine operating conditions. Soot is sampled at various engine operating conditions of a commercial 2.4 L GDI engine with a naturally aspirated, homogeneous, and stoichiometric operation strategy. The oxidation reactivity, ash composition, and carbon nanostructure of the GDI soot samples are analyzed using thermogravimetric analysis (TGA), scanning electron microscope–energy-dispersive spectroscopy (SEM-EDS), high-resolution transmission electron microscopy (HR-TEM), and Raman spectroscopy. Based on the analyses, a global GDI soot oxidation mechanism is proposed which includes the effects of soluble organic fractions (SOF)/weakly bonded carbon (WBC), andmore » three types of ash on GDI soot oxidation. The results show that GDI soot contains an order of magnitude higher ash fraction than does conventional diesel soot, and oxidation reactivity is significantly enhanced by the catalytic effects of ash, as a function of ash content in soot. A modified empirical kinetic correlation for GDI soot oxidation is suggested on the basis of the results, and the modified kinetic correlation predicts the GDI soot oxidation rate accurately for various engine operation points at wide ranges of soot conversion and temperature without modifying kinetic parameters. The kinetic parameters are determined from isothermal and non-isothermal thremogravimetric analysis (TGA) soot oxidation tests; the methods are elucidated in detail.« less

Oxidation characteristics of gasoline direct-injection (GDI) engine soot: Catalytic effects of ash and modified kinetic correlation

DOE PAGES

Choi, Seungmok; Seong, Heeje

2015-03-02

In this paper, experimental analyses are conducted into the GDI soot oxidation characteristics as dependent on engine operating conditions. Soot is sampled at various engine operating conditions of a commercial 2.4 L GDI engine with a naturally aspirated, homogeneous, and stoichiometric operation strategy. The oxidation reactivity, ash composition, and carbon nanostructure of the GDI soot samples are analyzed using thermogravimetric analysis (TGA), scanning electron microscope–energy-dispersive spectroscopy (SEM-EDS), high-resolution transmission electron microscopy (HR-TEM), and Raman spectroscopy. Based on the analyses, a global GDI soot oxidation mechanism is proposed which includes the effects of soluble organic fractions (SOF)/weakly bonded carbon (WBC), andmore » three types of ash on GDI soot oxidation. The results show that GDI soot contains an order of magnitude higher ash fraction than does conventional diesel soot, and oxidation reactivity is significantly enhanced by the catalytic effects of ash, as a function of ash content in soot. A modified empirical kinetic correlation for GDI soot oxidation is suggested on the basis of the results, and the modified kinetic correlation predicts the GDI soot oxidation rate accurately for various engine operation points at wide ranges of soot conversion and temperature without modifying kinetic parameters. The kinetic parameters are determined from isothermal and non-isothermal thremogravimetric analysis (TGA) soot oxidation tests; the methods are elucidated in detail.« less

Concurrent agglomeration and straining govern the transport of 14C-labeled few-layer graphene in saturated porous media.

PubMed

Su, Yu; Gao, Bin; Mao, Liang

2017-05-15

Deposition of graphene on environmental surfaces will dictate its transport and risks. In this work, the deposition, mobilization, and transport of 14 C-labeled few-layer graphene (FLG) in saturated quartz sand were systematically examined. Increasing solution ionic strength (IS) (1-100 mmol/L NaCl) resulted in greater retention of FLG (33-89%) in the sand and more hyper-exponential distribution of FLG along the sand column. Only a small fraction (≤7.4%) of the retained FLG was remobilized due to perturbation of IS by deionized water. These results indicate that trapping in pore spaces (i.e., physical straining) plays a dominant role in FLG deposition rather than attachment onto the surfaces of the sand. When IS, FLG input concentration, and flow velocity favor particle-particle interaction over particle-collector interaction, concurrent agglomeration within the pores promotes straining. In addition, electrostatic and steric repulsion that derived from the adsorbed organic macromolecules on FLG effectively reduced agglomeration and thereby enhanced transport and release of FLG. Moreover, the recovery of FLG (that deposited at 100 mmol/L NaCl) in the effluent reached 33% after speeding up the deionized water flushing rate. These findings highlight the need for FLG management in view of variations in transport behavior when assessing water quality and associated risks. Copyright © 2017 Elsevier Ltd. All rights reserved.

Modeling of particle agglomeration in nanofluids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krishna, K. Hari; Neti, S.; Oztekin, A.

2015-03-07

Agglomeration strongly influences the stability or shelf life of nanofluid. The present computational and experimental study investigates the rate of agglomeration quantitatively. Agglomeration in nanofluids is attributed to the net effect of various inter-particle interaction forces. For the nanofluid considered here, a net inter-particle force depends on the particle size, volume fraction, pH, and electrolyte concentration. A solution of the discretized and coupled population balance equations can yield particle sizes as a function of time. Nanofluid prepared here consists of alumina nanoparticles with the average particle size of 150 nm dispersed in de-ionized water. As the pH of the colloid wasmore » moved towards the isoelectric point of alumina nanofluids, the rate of increase of average particle size increased with time due to lower net positive charge on particles. The rate at which the average particle size is increased is predicted and measured for different electrolyte concentration and volume fraction. The higher rate of agglomeration is attributed to the decrease in the electrostatic double layer repulsion forces. The rate of agglomeration decreases due to increase in the size of nano-particle clusters thus approaching zero rate of agglomeration when all the clusters are nearly uniform in size. Predicted rates of agglomeration agree adequate enough with the measured values; validating the mathematical model and numerical approach is employed.« less

Spatial Linkage and Urban Expansion: AN Urban Agglomeration View

NASA Astrophysics Data System (ADS)

Jiao, L. M.; Tang, X.; Liu, X. P.

2017-09-01

Urban expansion displays different characteristics in each period. From the perspective of the urban agglomeration, studying the spatial and temporal characteristics of urban expansion plays an important role in understanding the complex relationship between urban expansion and network structure of urban agglomeration. We analyze urban expansion in the Yangtze River Delta Urban Agglomeration (YRD) through accessibility to and spatial interaction intensity from core cities as well as accessibility of road network. Results show that: (1) Correlation between urban expansion intensity and spatial indicators such as location and space syntax variables is remarkable and positive, while it decreases after rapid expansion. (2) Urban expansion velocity displays a positive correlation with spatial indicators mentioned above in the first (1980-1990) and second (1990-2000) period. However, it exhibits a negative relationship in the third period (2000-2010), i.e., cities located in the periphery of urban agglomeration developing more quickly. Consequently, the hypothesis of convergence of urban expansion in rapid expansion stage is put forward. (3) Results of Zipf's law and Gibrat's law show urban expansion in YRD displays a convergent trend in rapid expansion stage, small and medium-sized cities growing faster. This study shows that spatial linkage plays an important but evolving role in urban expansion within the urban agglomeration. In addition, it serves as a reference to the planning of Yangtze River Delta Urban Agglomeration and regulation of urban expansion of other urban agglomerations.

Superheated fuel injection for combustion of liquid-solid slurries

DOEpatents

Robben, Franklin A.

1985-01-01

A method and device for obtaining, upon injection, flash evaporation of a liquid in a slurry fuel to aid in ignition and combustion. The device is particularly beneficial for use of coal-water slurry fuels in internal combustion engines such as diesel engines and gas turbines, and in external combustion devices such as boilers and furnaces. The slurry fuel is heated under pressure to near critical temperature in an injector accumulator, where the pressure is sufficiently high to prevent boiling. After injection into a combustion chamber, the water temperature will be well above boiling point at a reduced pressure in the combustion chamber, and flash boiling will preferentially take place at solid-liquid surfaces, resulting in the shattering of water droplets and the subsequent separation of the water from coal particles. This prevents the agglomeration of the coal particles during the subsequent ignition and combustion process, and reduces the energy required to evaporate the water and to heat the coal particles to ignition temperature. The overall effect will be to accelerate the ignition and combustion rates, and to reduce the size of the ash particles formed from the coal.

Multi-fuel combustor for gas turbine engines: Phase 1, Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melconian, J.O.; Marden, W.W., III

An innovative can combustor configuration has been developed for gas turbine engines which has the potential of burning fuels ranging from gasoline to coal/water slurries at high efficiencies. The design is based on a Variable Residence Time (VRT) concept which allows large and agglomerated fuel particles adequate time to completely burn. High durability of the combustor is achieved by dual function use of the incoming air. For applications which require the burning of coal/water slurries, the design has the capability of removing the ash particles directly from the primary zone of the combustor. It is anticipated that because of themore » small size requirement of this combustor design, existing gas turbine engines could be retrofitted within the confines of the current engine envelope. In Phase 1, the feasibility of the concept was successfully demonstrated by three-dimensional mathematical modeling and water analogue tests. The Plexiglas model used in the water analogue tests was designed to fit the current production engine of a major manufacturer. 19 figs., 2 tabs.« less

Chemical conversion of sulphur dioxide on Eyjafjallajökull's volcanic ash from the 2010 eruption

NASA Astrophysics Data System (ADS)

Dupart, Yoan; Burel, Laurence; Delichere, Pierre; George, Christian; D'Anna, Barbara

2013-04-01

Volcanic eruptions induce important climatic and weather modifications. When volcanic ashes are emitted into the atmosphere they can travel for several weeks according to their size distribution and altitude of the emission. Eyjafjallajökull eruption, between April 14th and May 23th, is considered as a medium-size eruption. The upper level winds advected ashes over the UK and continental Europe. During volcanic eruptions high amounts of SO2 were injected into the atmosphere (from 50 to 200 ppbv)[1]. Previous works showed that SO2 could be convert into sulfate on mineral dust surfaces under dark conditions[2]. However, no conversion has been studied with real volcanic ashes and under day conditions (light exposure). For this study, real Eyjafjallajökull's ashes samples, collected on the 2010.04.18 at Seljavellir, were used. The ashes were deposited on a horizontal cylindrical coated-wall flow tube reactor surrounded by 5 fluorescent lamps (340-420 nm). The kinetic studies revealed that the presence of UV-A irradiation enhanced the conversion of SO2 on ashes samples. Moreover chemical analyses as XPS, Ion Chromatography and SEM were performed on volcanic ashes before and after exposition to SO2. XPS and ion chromatography analyzes showed that the presence of light increase the SO2 uptake on ashes surfaces and convert it into ions sulphate. Beside SEM analyses disclosed that the conversion takes place systematically on an iron oxide site . By combining kinetics and chemical analysis we are able to propose a new mechanism for the SO2 conversion on mineral surfaces under light conditions. 1. Self, S., et al., Volatile fluxes during flood basalt eruptions and potential effects on the global environment: A Deccan perspective. Earth and Planetary Science Letters, 2006. 248(1-2): p. 518-532. 2. Zhang et al., Heterogeneous Reactions of Sulfur Dioxide on Typical Mineral Particles, J. Phys. Chem. B, 2006

Characterization of Fly and Bottom Ashes Mixtures Treated using Sodium Lauryl Sulphate and Polyvinyl Alcohol

NASA Astrophysics Data System (ADS)

Robert, C. G.; Ayob, A.; Zaki, M. F. Muhammad; Razali, M. E.; Lew, E. V.; Hong, P. Y.

2018-03-01

Malaysia promotes coal as an option for solid fuel in electric power generation. Demanding of electricity needs, therefore, has led to increase the coal consumption and thus producing more coal waste products. The disposal of coal waste ashes has been a main concern to power generation station due to the need of disposal sites and operational costs. This study investigates the composition of fly ash (FA) and bottom ash (BA) mixtures with difference component percentage treated with sodium lauryl sulphate (SLS) and polyvinyl alcohol (PVA) at 1.5 and 2.5 wt% solutions and examined in terms of specific gravity, pH, maximum dry density properties, and its surface morphology. Although the chemical composition of the SLS and PVA treated fly and bottom ashes studied in this current work is not altered extensively, significant changes could be observed in its physicochemical properties. Chemically treated fly and bottom ashes mixtures with SLS and PVA at 1.5 wt% solution exhibited specific gravity of 1.97 to 2.92 and high pH values within range of 9.28 to 10.52. The mixture of BA:FA=0:1 ratio depicting high maximum dry density of 1.35 to 1.56 g/cm3 in both SLS and PVA solutions at 1.5 and 2.5 wt%. Scanning electron microscopy image shows distinct surface morphologies of SLS-treated fly and bottom ashes mixture that the particles are packed closely, strongly bonded similar to popcorn shape due to the effect of active silanol groups acted on coal ashes surface with the presence of Al-O/Si-O/other oxides. These findings suggest that higher level of chemical interaction between the fly and bottom ashes particles, significantly enhances pozzolanic reactions such as shear strength, plasticity, cementing properties, and thus other engineering properties.

Effect of dilution and ash supplement on the bio-methane potential of palm oil mill effluent (POME)

NASA Astrophysics Data System (ADS)

Jijai, Sunwanee; Muleng, Saina; Siripatana, Chairat

2017-08-01

This study aimed to evaluate the bio-methane potential of POME at different dilutions (100, 80, 60, 40, and 20 percent of initial POME) and different pH dues to different levels of ash supplement. Five different amounts of ash were added to digesters (0, 2, 4, 6, and 8 grams of ash were added to 170 ml of POME respectively). The digesters were operated in batch anaerobic digestion systems at room temperature (28-30 °C) and the experiments were performed in duplicate manner. The results showed that POME without dilution gave highest cumulative biogas (950 ml). However, 80% dilution from original POME gave the highest methane yield (45.83 mL CH4/ gCODadded or 103.13 mL CH4/ gCODremoved). Finally, the results of experiment 2, this adding ash into POME increased pH as well as enhanced the biogas production. It was found that adding ash at the ash:POME ratio of 2 g: 170 ml gave the highest both the cumulative biogas and methane yield (1,520 mL and 218.79 mL CH4/ gCODremoved respectively). The addition of ash in the raw waste of POME gave the pH in the range of criteria and highest bio-methane potential. The modified Gompertz equation, Schnute as well as Monod kinetic models were used to compare the data from the experiments. It was found that the factors that affected included, the bio-methane production and the kinetic parameters (the maximum specific methane production rates (Rm ml/day) and the methane production potential (P, mL)), initial COD, nutrients, levels of dilution, and initial pH (by adding different level of ash). However, λ (lag phase period) was not affected by initial COD and other factors. While Monod kinetics provides valuable insight in explaining what could happen behind the systematic trends.

Use of municipal solid waste incineration bottom ashes in alkali-activated materials, ceramics and granular applications: A review.

PubMed

Silva, R V; de Brito, J; Lynn, C J; Dhir, R K

2017-10-01

This paper presents a literature review on the incorporation of municipal solid waste incinerated bottom ash as raw material in several markets, other than those where it is conventionally used, such as geotechnical applications and road pavement construction. The main findings of an ample selection of experimental investigations on the use of the bottom ash as precursor of alkali-activated materials, as an adsorbent material for the removal of hazardous elements from wastewater and landfill gases, as soil replacement in agricultural activities, as partial or complete substitute of raw materials for the manufacture of ceramic-based products, as landfill cover and as biogas production enhancer, were gathered, collated and analysed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comments on an Analytical Thermal Agglomeration for Problems with Surface Growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hodge, N. E.

2017-03-22

Up until Dec 2016, the thermal agglomeration was very heuristic, and as such, difficult to define. The lack of predictability became problematic, and the current notes represent the first real attempt to systematize the specification of the agglomerated process parameters.

Biomass ashes from pyrolytic wood liquefaction as novel soil amendments

NASA Astrophysics Data System (ADS)

Fernández-Delgado Juárez, Marina; Gómez Brandón, María; Mazzier, Thomas; Schönegger, Deborah; Hermanns, Roy; Leijenhorst, Evert; Insam, Heribert

2017-04-01

What happens when an old soil amendment is in fact a new one? Traditionally, ashes from biomass combustion were considered as a valuable resource, and widely used as an agricultural soil amendment. However, in recent decades we have been reluctant to apply them to soils, despite the increase in the production of combustion ashes resulting from the development of new fuels derived from biomass residues. The production of Fast Pyrolysis Bio Oil (FPBO) out of various lignocellulosic biomass streams is one of the newest technologies for gaining a liquid biofuel that can be seen as a future substitute for mineral oils. During the pyrolysis process, the by-products (charcoal and low calorific gases) are combusted to generate energy, resulting in the production of ashes that contain the majority of the minerals and salts originally present in the feedstock. The main objective of the present work is to investigate if the recovered ashes from the pyrolysis process can be used as a soil amendment. A greenhouse trial was set up in order to evaluate the impact of the ashes on an acid grassland soil (eutric Cambisol) from the region of Tyrol (Austria). A two-level experimental design (ash treatment, and plant effect) was set up. The ashes were mixed with the soil columns at a ratio of 1% (w:w, fresh weight). A control treatment that consisted of soil without the addition of ashes was also included. Moreover, to understand the effect that the ashes would have on crop growth, ten seeds of a traditional wheat variety (Tiroler Früher Dinkel; Triticum aestivum subsp. spelta), were placed in half of the columns with and without ashes, so as to determine the seed germination index and plant growth. Moreover, specific microbial groups related to N cycle were quantified by real-time PCR. A total of 24 experimental units (2 ash treatments x 2 incubation times x 2 plant levels x 3 replicates) were analysed. After an equilibration period of 24 h at 4 °C (referred as time zero), the columns were arranged in a completely randomized design and destructively sampled after 60 and 100 days. The amendment with ashes induced a soil pH increase of almost 2 units over time and independent of the crop presence. Moreover, ash addition did also increase soil plant available P and dissolved organic carbon content; however, it also increased nitrogen loss to the soil eluates compared to the control. On the other hand, the presence of ashes enhanced both plant growth and grain yield after 60 and 100 days. Similar effects have been observed when "traditional" biomass ashes have been applied to agricultural soils, leading us to conclude that ashes derived from FPBO process might be used for agricultural purposes. The Residue2Heat project has received funding from the European Union's Horizon 2020 Research and Innovation programme under Grant Agreement No. 654650.

The Bossoroca Complex, São Gabriel Terrane, Dom Feliciano Belt, southernmost Brazil: Usbnd Pb geochronology and tectonic implications for the neoproterozoic São Gabriel Arc

NASA Astrophysics Data System (ADS)

Gubert, Mauricio Lemos; Philipp, Ruy Paulo; Stipp Basei, Miguel Angelo

2016-10-01

Usbnd Pb LA-ICPMS geochronological analyses were carried out on zircon grains from metavolcanic rocks of the Bossoroca Complex and for one ash tuff of the Acampamento Velho Formation of the Camaquã Basin, in order to understand the evolution of the Neoproterozoic São Gabriel magmatic arc. A total of 42 analyses of igneous zircon grains were performed in three samples. The results yielded Usbnd Pb ages of 767.2 ± 2.9 Ma for the metavolcanic agglomerate (BOS-02); 765 ± 10 Ma for the metacrystal tuff (BOS-03) and 565.8 ± 4.8 Ma for the ash tuff (BOS-04). The Orogenic Cycle in Brazil is characterized by a set of orogenic belts consisting of petrotectonic associations juxtaposed by two collisional events that occurred at the end of the Neoproterozoic. In southern Brazil this orogeny formed the Dom Feliciano Belt, a unit composed of associations of rocks developed during two major orogenic events called São Gabriel (900-680 Ma) and Dom Feliciano (650-540 Ma). The main São Gabriel associations are tectonically juxtaposed as elongated strips according to the N20-30°E direction, bounded by ductile shear zones. The Bossoroca Complex comprises predominantly metavolcano-sedimentary rocks, characterized by medium-K calc-alkaline association generated in a cordillera-type magmatic arc. The volcanism occurred in sub-aerial environment, developing deposits generated by flow, resurgence and fall, sporadically interrupted by subaqueous epiclastic deposits, suggesting an arc related basin. The São Gabriel Terrane contains the petrotectonic units that represent the closure of the Charrua Ocean associated to the subduction period of the Brasiliano Orogenic Cycle in the Sul-rio-grandense Shield.

Molecular dynamics simulations of the effect of waviness and agglomeration of CNTs on interface strength of thermoset nanocomposites.

PubMed

Alian, A R; Meguid, S A

2017-02-08

Most existing molecular dynamics simulations in nanoreinforced composites assume carbon nanotubes (CNTs) to be straight and uniformly dispersed within thermoplastics. In reality, however, CNTs are typically curved, agglomerated and aggregated as a result of van der Waal interactions and electrostatic forces. In this paper, we account for both curvature and agglomeration of CNTs in extensive molecular dynamic (MD) simulations. The purpose of these simulations is to evaluate the influence of waviness and agglomeration of these curved and agglomerated CNTs on the interfacial strength of thermoset nanocomposite and upon their load transfer capability. Two aspects of the work were accordingly examined. In the first, realistic carbon nanotubes (CNTs) of the same length but varied curvatures were embedded in thermoset polymer composites and simulations of pull-out tests were conducted to evaluate the corresponding interfacial shear strength (ISS). In the second, the effect of the agglomerate size upon the ISS was determined using bundles of CNTs of different diameters. The results of our MD simulations revealed the following. The pull-out force of the curved CNTs is significantly higher than its straight counterpart and increases further with the increase in the waviness of the CNTs. This is attributed to the added pull-out energy dissipated in straightening the CNTs during the pull-out process. It also reveals that agglomeration of CNTs leads to a reduction in the ISS and poor load transferability, and that this reduction is governed by the size of the agglomerate. The simulation results were also used to develop a generalized relation for the ISS that takes into consideration the effect of waviness and agglomeration of CNTs of CNT-polymer composites.

Tensile Characterization of Injection-Molded Fuzzy Glass Fiber/Nylon Composite Material

DTIC Science & Technology

2016-05-01

enhanced reinforcement ( CER ) in a nylon matrix. A majority of the masterbatch CER material research is focused on electromagnetic shielding applications...however, the CER system, with the CNT network fixed to the host fiber, provides a novel approach of minimizing CNT agglomeration. Tensile specimens are...injection molded with varying weight percentages of CER to evaluate effect of the reinforcement on the mechanical properties. Tension testing showed

Successfully use agglomeration for size enlargement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pietsch, W.

1996-04-01

The processing of fine and ultrafine particles by size enlargement finds an ever increasing application. At the same time, undesirable agglomeration such as buildup, caking, bridging, and uncontrolled aggregation of fine particles can occur during processing and handling of these particulate solids. This article will provide a survey of the phenomena of agglomeration and discuss the unit operation of size enlargement by agglomeration. This article is also an invitation, particularly to young engineers, to become interested in agglomeration. Considering that mechanical process technologies are requiring more energy every year than any other group of consumers and efficiencies are typically inmore » the single digits or teens at best, considerable rewards can be expected from the development of scientifically modified, more energy-efficient methods and equipment.« less

Stacked multilayers of alternating reduced graphene oxide and carbon nanotubes for planar supercapacitors

NASA Astrophysics Data System (ADS)

Moon, Geon Dae; Joo, Ji Bong; Yin, Yadong

2013-11-01

A simple layer-by-layer approach has been developed for constructing 2D planar supercapacitors of multi-stacked reduced graphene oxide and carbon nanotubes. This sandwiched 2D architecture enables the full utilization of the maximum active surface area of rGO nanosheets by using a CNT layer as a porous physical spacer to enhance the permeation of a gel electrolyte inside the structure and reduce the agglomeration of rGO nanosheets along the vertical direction. As a result, the stacked multilayers of rGO and CNTs are capable of offering higher output voltage and current production.A simple layer-by-layer approach has been developed for constructing 2D planar supercapacitors of multi-stacked reduced graphene oxide and carbon nanotubes. This sandwiched 2D architecture enables the full utilization of the maximum active surface area of rGO nanosheets by using a CNT layer as a porous physical spacer to enhance the permeation of a gel electrolyte inside the structure and reduce the agglomeration of rGO nanosheets along the vertical direction. As a result, the stacked multilayers of rGO and CNTs are capable of offering higher output voltage and current production. Electronic supplementary information (ESI) available: Experimental details, SEM and TEM images and additional electrochemical data. See DOI: 10.1039/c3nr04339h

A MODEL FOR FINE PARTICLE AGGLOMERATION IN CIRCULATING FLUIDIZED BED ABSORBERS

EPA Science Inventory

A model for fine particle agglomeration in circulating fluidized bed absorbers (CFBAS) has been developed. It can model the influence of different factors on agglomeration, such as the geometry of CFBAs, superficial gas velocity, initial particle size distribution, and type of ag...

Urban Planning Problems of Agglomerations

NASA Astrophysics Data System (ADS)

Olenkov, V. D.; Tazeev, N. T.

2017-11-01

The article explores the state of the air basin of the Chelyabinsk agglomeration and gives the examples of solutions for the pollution problems from the point of view of city planning. The main features and structure of the modern urban agglomerations are considered, the methods for determining their boundaries are studied and the main problems are identified. The study of the boundaries and territorial structure of the Chelyabinsk urban agglomeration is conducted, and a general description of the territory is given. The data on the change in the volume of pollutant emissions into the atmosphere and the index of atmospheric pollution for the period 2003-2015 are given basing on the annual comprehensive reports regarding the state of the environment. The review of the world experience of city-planning actions on the decision of ecological problems is carried out. The most suitable ways for the ecological problems solving in the Chelyabinsk agglomeration are considered. The authors give recommendations for the ecological situation improving in the territory of the Chelyabinsk agglomeration.

Morphological characterization of diesel soot agglomerates based on the Beer-Lambert law

NASA Astrophysics Data System (ADS)

Lapuerta, Magín; Martos, Francisco J.; José Expósito, Juan

2013-03-01

A new method is proposed for the determination of the number of primary particles composing soot agglomerates emitted from diesel engines as well as their individual fractal dimension. The method is based on the Beer-Lambert law and it is applied to micro-photographs taken in high resolution transmission electron microscopy. Differences in the grey levels of the images lead to a more accurate estimation of the geometry of the agglomerate (in this case radius of gyration) than other methods based exclusively on the planar projections of the agglomerates. The method was validated by applying it to different images of the same agglomerate observed from different angles of incidence, and proving that the effect of the angle of incidence is minor, contrary to other methods. Finally, the comparisons with other methods showed that the size, number of primary particles and fractal dimension (the latter depending on the particle size) are usually underestimated when only planar projections of the agglomerates are considered.

Nanoparticle agglomeration in an evaporating levitated droplet for different acoustic amplitudes

NASA Astrophysics Data System (ADS)

Tijerino, Erick; Basu, Saptarshi; Kumar, Ranganathan

2013-01-01

Radiatively heated levitated functional droplets with nanosilica suspensions exhibit three distinct stages namely pure evaporation, agglomeration, and finally structure formation. The temporal history of the droplet surface temperature shows two inflection points. One inflection point corresponds to a local maximum and demarcates the end of transient heating of the droplet and domination of vaporization. The second inflection point is a local minimum and indicates slowing down of the evaporation rate due to surface accumulation of nanoparticles. Morphology and final precipitation structures of levitated droplets are due to competing mechanisms of particle agglomeration, evaporation, and shape deformation. In this work, we provide a detailed analysis for each process and propose two important timescales for evaporation and agglomeration that determine the final diameter of the structure formed. It is seen that both agglomeration and evaporation timescales are similar functions of acoustic amplitude (sound pressure level), droplet size, viscosity, and density. However, we show that while the agglomeration timescale decreases with initial particle concentration, the evaporation timescale shows the opposite trend. The final normalized diameter can be shown to be dependent solely on the ratio of agglomeration to evaporation timescales for all concentrations and acoustic amplitudes. The structures also exhibit various aspect ratios (bowls, rings, spheroids) which depend on the ratio of the deformation timescale (tdef) and the agglomeration timescale (tg). For tdef

Novel Binders and Methods for Agglomeration of Ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. K. Kawatra; T. C. Eisele; K. A. Lewandowski

2006-03-31

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that willmore » work satisfactorily at a reasonable cost. A primary example of this is copper heap leaching, where there are no binders currently encountered in this acidic environment process. As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching. The active involvement of our industrial partners will help to ensure rapid commercialization of any agglomeration technologies developed by this project.« less

Novel Binders and Methods for Agglomeration of Ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. K. Kawatra; T. C. Eisele; J. A. Gurtler

2005-09-30

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that willmore » work satisfactorily at a reasonable cost. A primary example of this is copper heap leaching, where there are no binders currently encountered in this acidic environment process. As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching. The active involvement of our industrial partners will help to ensure rapid commercialization of any agglomeration technologies developed by this project.« less

Coal combustion products: trash or treasure?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, T.

2006-07-15

Coal combustion by-products can be a valuable resource to various industries. The American Coal Ash Association (ACAA) collects data on production and uses of coal combustion products (CCPs). 122.5 million tons of CCPs were produced in 2004. The article discusses the results of the ACCA's 2004 survey. Fly ash is predominantly used as a substitute for Portland cement; bottom ash for structural fill, embankments and paved road cases. Synthetic gypsum from the FGD process is commonly used in wallboard. Plant owners are only likely to have a buyer for a portion of their CCPs. Although sale of hot water (frommore » Antelope Valley Station) from condensers for use in a fish farm to raise tilapia proved unviable, the Great Plains Synfuels Plant which manufactures natural gas from lignite produces a wide range of products including anhydrous ammonia, phenol, krypton, carbon dioxide (for enhanced oil recovery), tar oils and liquid nitrogen. ACCA's goal is to educate people about CCPs and how to make them into useful products, and market them, in order to reduce waste disposal and enhance revenue. The article lists members of the ACCA. 2 photos., 1 tab.« less

Mutant MMP-9 and HGF gene transfer enhance resolution of CCl4-induced liver fibrosis in rats: role of ASH1 and EZH2 methyltransferases repression.

PubMed

Atta, Hussein; El-Rehany, Mahmoud; Hammam, Olfat; Abdel-Ghany, Hend; Ramzy, Maggie; Roderfeld, Martin; Roeb, Elke; Al-Hendy, Ayman; Raheim, Salama Abdel; Allam, Hatem; Marey, Heba

2014-01-01

Hepatocyte growth factor (HGF) gene transfer inhibits liver fibrosis by regulating aberrant cellular functions, while mutant matrix metalloproteinase-9 (mMMP-9) enhances matrix degradation by neutralizing the elevated tissue inhibitor of metalloproteinase-1 (TIMP-1). It was shown that ASH1 and EZH2 methyltransferases are involved in development of liver fibrosis; however, their role in the resolution phase of liver fibrosis has not been investigated. This study evaluated the role of ASH1 and EZH2 in two mechanistically different therapeutic modalities, HGF and mMMP-9 gene transfer in CCl4 induced rat liver fibrosis. Liver fibrosis was induced in rats with twice a week intraperitoneal injection of CCl4 for 8 weeks. Adenovirus vectors encoding mMMP-9 or HGF genes were injected through tail vein at weeks six and seven and were sacrificed one week after the second injection. A healthy animal group was likewise injected with saline to serve as a negative control. Rats treated with mMMP-9 showed significantly lower fibrosis score, less Sirius red stained collagen area, reduced hydroxyproline and ALT concentration, decreased transforming growth factor beta 1 (TGF-β1) mRNA and lower labeling indices of α smooth muscle actin (α-SMA) and proliferating cell nuclear antigen (PCNA) stained cells compared with HGF- or saline-treated rats. Furthermore, TIMP-1 protein expression in mMMP-9 group was markedly reduced compared with all fibrotic groups. ASH1 and EZH2 protein expression was significantly elevated in fibrotic liver and significantly decreased in mMMP-9- and HGF-treated compared to saline-treated fibrotic livers with further reduction in the mMMP-9 group. Gene transfer of mMMP-9 and HGF reduced liver fibrosis in rats. ASH1 and EZH2 methyltransferases are significantly reduced in mMMP-9 and HGF treated rats which underlines the central role of these enzymes during fibrogenesis. Future studies should evaluate the role of selective pharmacologic inhibitors of ASH1 and EZH2 in resolution of liver fibrosis.

Surfactant protein A (SP-A) inhibits agglomeration and macrophage uptake of toxic amine modified nanoparticles.

PubMed

McKenzie, Zofi; Kendall, Michaela; Mackay, Rose-Marie; Whitwell, Harry; Elgy, Christine; Ding, Ping; Mahajan, Sumeet; Morgan, Cliff; Griffiths, Mark; Clark, Howard; Madsen, Jens

2015-01-01

The lung provides the main route for nanomaterial exposure. Surfactant protein A (SP-A) is an important respiratory innate immune molecule with the ability to bind or opsonise pathogens to enhance phagocytic removal from the airways. We hypothesised that SP-A, like surfactant protein D, may interact with inhaled nanoparticulates, and that this interaction will be affected by nanoparticle (NP) surface characteristics. In this study, we characterise the interaction of SP-A with unmodified (U-PS) and amine-modified (A-PS) polystyrene particles of varying size and zeta potential using dynamic light scatter analysis. SP-A associated with both 100 nm U-PS and A-PS in a calcium-independent manner. SP-A induced significant calcium-dependent agglomeration of 100 nm U-PS NPs but resulted in calcium-independent inhibition of A-PS self agglomeration. SP-A enhanced uptake of 100 nm U-PS into macrophage-like RAW264.7 cells in a dose-dependent manner but in contrast inhibited A-PS uptake. Reduced association of A-PS particles in RAW264.7 cells following pre-incubation of SP-A was also observed with coherent anti-Stokes Raman spectroscopy. Consistent with these findings, alveolar macrophages (AMs) from SP-A(-/-) mice were more efficient at uptake of 100 nm A-PS compared with wild type C57Bl/6 macrophages. No difference in uptake was observed with 500 nm U-PS or A-PS particles. Pre-incubation with SP-A resulted in a significant decrease in uptake of 100 nm A-PS in macrophages isolated from both groups of mice. In contrast, increased uptake by AMs of U-PS was observed after pre-incubation with SP-A. Thus we have demonstrated that SP-A promotes uptake of non-toxic U-PS particles but inhibits the clearance of potentially toxic A-PS particles by blocking uptake into macrophages.

Nanoantioxidant-driven plasmon enhanced proton-coupled electron transfer

NASA Astrophysics Data System (ADS)

Sotiriou, Georgios A.; Blattmann, Christoph O.; Deligiannakis, Yiannis

2015-12-01

Proton-coupled electron transfer (PCET) reactions involve the transfer of a proton and an electron and play an important role in a number of chemical and biological processes. Here, we describe a novel phenomenon, plasmon-enhanced PCET, which is manifested using SiO2-coated Ag nanoparticles functionalized with gallic acid (GA), a natural antioxidant molecule that can perform PCET. These GA-functionalized nanoparticles show enhanced plasmonic response at near-IR wavelengths, due to particle agglomeration caused by the GA molecules. Near-IR laser irradiation induces strong local hot-spots on the SiO2-coated Ag nanoparticles, as evidenced by surface enhanced Raman scattering (SERS). This leads to plasmon energy transfer to the grafted GA molecules that lowers the GA-OH bond dissociation enthalpy by at least 2 kcal mol-1 and therefore facilitates PCET. The nanoparticle-driven plasmon-enhancement of PCET brings together the so far unrelated research domains of nanoplasmonics and electron/proton translocation with significant impact on applications based on interfacial electron/proton transfer.Proton-coupled electron transfer (PCET) reactions involve the transfer of a proton and an electron and play an important role in a number of chemical and biological processes. Here, we describe a novel phenomenon, plasmon-enhanced PCET, which is manifested using SiO2-coated Ag nanoparticles functionalized with gallic acid (GA), a natural antioxidant molecule that can perform PCET. These GA-functionalized nanoparticles show enhanced plasmonic response at near-IR wavelengths, due to particle agglomeration caused by the GA molecules. Near-IR laser irradiation induces strong local hot-spots on the SiO2-coated Ag nanoparticles, as evidenced by surface enhanced Raman scattering (SERS). This leads to plasmon energy transfer to the grafted GA molecules that lowers the GA-OH bond dissociation enthalpy by at least 2 kcal mol-1 and therefore facilitates PCET. The nanoparticle-driven plasmon-enhancement of PCET brings together the so far unrelated research domains of nanoplasmonics and electron/proton translocation with significant impact on applications based on interfacial electron/proton transfer. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04942c

Rock geochemistry in the Mahd adh Dhahab district, Kingdom of Saudi Arabia

USGS Publications Warehouse

Worl, R.G.; Doebrich, J.L.; Allen, M.S.; Afifi, A.M.; Ebens, R.J.

1987-01-01

Anomalous values of gold, silver, lead, and to a lesser extent copper and zinc in surface rock samples clearly delineated the northern mineralized zone in the upper agglomerate, and an east-vein area and west-vein area of the southern mineralized zone in the lower agglomerate. A third geochemically anomalous area occurs farther to the west in the lower agglomerate, suggesting that mineralization may have extended at least to this area along the lower agglomerate-lower tuff contact, and possibly even further to the west.

Search for the contamination source of butyltin compounds in wine: agglomerated cork stoppers.

PubMed

Jiang, Gui-Bin; Liu, Ji-Yan; Zhou, Qun-Fang

2004-08-15

A possible butyltin contamination source in wine was studied in this paper. Agglomerated cork stoppers, which were produced in Portugal, Spain, and Italy, used in wine bottles were examined. The domestic cork products, cork granules, and mucus used for cork products were also analyzed. The levels of mono- and dibutyltin compounds in corks were found in the range from <0.0024 to 3.3 and from <0.0029 to 6.7 microg of Sn/g, respectively. A low level of tributyltin contamination was also found in 2 of 31 tested samples. The presence of butyltin compounds in agglomerated cork stoppers was confirmed by GC-MS. Experimental results indicated that all overseas agglomerated cork stoppers studied contained mono- and/or dibutyltins. Butyltins were not detected in cork granules, mucus, most of the natural cork stoppers, and domestic agglomerated cork products. The concentrations of mono- and dibutyltins increased with the time in a 30-day experiment, showing that butyltin compounds can leach from agglomerated cork to the wine. When the butyltin concentrations in wine samples were compared with their levels in the corresponding agglomerated cork stoppers, a correlation was found. The potential harm of such food contamination was evaluated by the toxic research of butyltin compounds using Daphnia sp. as the experimental model.

Light scattering by low-density agglomerates of micron-sized grains with the PROGRA2 experiment

NASA Astrophysics Data System (ADS)

Hadamcik, E.; Renard, J.-B.; Lasue, J.; Levasseur-Regourd, A. C.; Blum, J.; Schraepler, R.

2007-07-01

This work was carried out with the PROGRA2 experiment, specifically developed to measure the angular dependence of the polarization of light scattered by dust particles. The samples are small agglomerates of micron-sized grains and huge, low number density agglomerates of the same grains. The constituent grains (spherical or irregularly shaped) are made of different non-absorbing and absorbing materials. The small agglomerates, in a size range of a few microns, are lifted by an air draught. The huge centimeter-sized agglomerates, produced by random ballistic deposition of the grains, are deposited on a flat surface. The phase curves obtained for monodisperse, micron-sized spheres in agglomerates are obviously not comparable to the ‘smooth’ phase curves obtained by remote observations of cometary dust or asteroidal regoliths but they are used for comparison with numerical calculations to a better understanding of the light scattering processes. The phase curves obtained for irregular grains in agglomerates are similar to those obtained by remote observations, with a negative branch at phase angles smaller than 20° and a maximum polarization decreasing with increasing albedo. These results, coupled with remote observations in the solar system, should provide a better understanding of the physical properties of solid particles and their variation in cometary comae and asteroidal regoliths.

Characterization of Propylene Glycol-Mitigated Freeze/Thaw Agglomeration of a Frozen Liquid nOMV Vaccine Formulation by Static Light Scattering and Micro-Flow Imaging.

PubMed

Mensch, Christopher D; Davis, Harrison B; Blue, Jeffrey T

2015-01-01

The purpose of this work was to investigate the susceptibility of an aluminum adjuvant and an aluminum-adjuvanted native outer membrane vesicle (nOMV) vaccine formulation to freeze/thaw-induced agglomeration using static light scattering and micro-flow Imaging analysis; and to evaluate the use of propylene glycol as a vaccine formulation excipient by which freeze/thaw-induced agglomeration of a nOMV vaccine formulation could be mitigated. Our results indicate that including 7% v/v propylene glycol in an nOMV containing aluminum adjuvanted vaccine formulation, mitigates freeze/thaw-induced agglomeration. We evaluated the effect of freeze-thawing on an aluminum adjuvant and an aluminum adjuvanted native outer membrane vesicle (nOMV) vaccine formulation. Specifically, we characterized the freeze/thaw-induced agglomeration through the use of static light scattering, micro-flow imaging, and cryo-electron microscopy analysis. Further, we evaluated the use of 0-9% v/v propylene glycol as an excipient which could be included in the formulation for the purpose of mitigating the agglomeration induced by freeze/thaw. The results indicate that using 7% v/v propylene glycol as a formulation excipient is effective at mitigating agglomeration of the nOMV vaccine formulation, otherwise induced by freeze-thawing. © PDA, Inc. 2015.

NOVEL BINDERS AND METHODS FOR AGGLOMERATION OF ORE

DOE Office of Scientific and Technical Information (OSTI.GOV)

S.K. Kawatra; T.C. Eisele; J.A. Gurtler

2005-04-01

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not breakdown during processing. However, for many important metal extraction processes there are no binders known that will workmore » satisfactorily. Primary examples of this are copper heap leaching, where there are no binders that will work in the acidic environment encountered in this process. As a result, operators of many facilities see large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching.« less

Novel Binders and Methods for Agglomeration of Ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. K. Kawatra; T. C. Eisele; J. A. Gurtler

2004-03-31

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that willmore » work satisfactorily. A primary example of this is copper heap leaching, where there are no binders that will work in the acidic environment encountered in this process. As a result, operators of acidic heap-leach facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of other agglomeration applications, particularly advanced primary ironmaking.« less

Experimental Investigation on Pore Structure Characterization of Concrete Exposed to Water and Chlorides

PubMed Central

Liu, Jun; Tang, Kaifeng; Qiu, Qiwen; Pan, Dong; Lei, Zongru; Xing, Feng

2014-01-01

In this paper, the pore structure characterization of concrete exposed to deionised water and 5% NaCl solution was evaluated using mercury intrusion porosity (MIP), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effects of calcium leaching, fly ash incorporation, and chloride ions on the evolution of pore structure characteristics were investigated. The results demonstrate that: (i) in ordinary concrete without any fly ash, the leaching effect of the cement products is more evident than the cement hydration effect. From the experimental data, Ca(OH)2 is leached considerably with the increase in immersion time. The pore structure of concrete can also be affected by the formation of an oriented structure of water in concrete materials; (ii) incorporation of fly ash makes a difference for the performance of concrete submersed in solutions as the total porosity and the pore connectivity can be lower. Especially when the dosage of fly ash is up to 30%, the pores with the diameter of larger than 100 nm show significant decrease. It demonstrates that the pore properties are improved by fly ash, which enhances the resistance against the calcium leaching; (iii) chlorides have a significant impact on microstructure of concrete materials because of the chemical interactions between the chlorides and cement hydrates. PMID:28788204

Assessment of soil contamination by (210)Po and (210)Pb around heavy oil and natural gas fired power plants.

PubMed

Al-Masri, M S; Haddad, Kh; Doubal, A W; Awad, I; Al-Khatib, Y

2014-06-01

Soil contamination by (210)Pb and (210)Po around heavy oil and natural gas power plants has been investigated; fly and bottom ash containing enhanced levels of (210)Pb and (210)Po were found to be the main source of surface soil contamination. The results showed that (210)Pb and (210)Po in fly-ash (economizer, superheater) is highly enriched with (210)Pb and (210)Po, while bottom-ash (boiler) is depleted. The highest (210)Pb and (210)Po activity concentrations were found to be in economizer ash, whereas the lowest activity concentration was in the recirculator ash. On the other hand, (210)Pb and (210)Po activity concentrations in soil samples were found to be higher inside the plant site area than those samples collected from surrounding areas. The highest levels were found in the vicinity of Mhardeh and Tishreen power plants; both plants are operated by heavy oil and natural fuels, while the lowest values were found to be in those samples collected from Nasrieh power plant, which is only operated by one type of fuel, viz. natural gas. In addition, the levels of surface soil contamination have decreased as the distance from the power plant site center increased. Copyright © 2014 Elsevier Ltd. All rights reserved.

Leachability of Heavy Metals from Lightweight Aggregates Made with Sewage Sludge and Municipal Solid Waste Incineration Fly Ash

PubMed Central

Wei, Na

2015-01-01

Lightweight aggregate (LWA) production with sewage sludge and municipal solid waste incineration (MSWI) fly ash is an effective approach for waste disposal. This study investigated the stability of heavy metals in LWA made from sewage sludge and MSWI fly ash. Leaching tests were conducted to find out the effects of MSWI fly ash/sewage sludge (MSWI FA/SS) ratio, sintering temperature and sintering time. It was found that with the increase of MSWI FA/SS ratio, leaching rates of all heavy metals firstly decreased and then increased, indicating the optimal ratio of MSWI fly ash/sewage sludge was 2:8. With the increase of sintering temperature and sintering time, the heavy metal solidifying efficiencies were strongly enhanced by crystallization and chemical incorporations within the aluminosilicate or silicate frameworks during the sintering process. However, taking cost-savings and lower energy consumption into account, 1100 °C and 8 min were selected as the optimal parameters for LWA sample- containing sludge production. Furthermore, heavy metal leaching concentrations under these optimal LWA production parameters were found to be in the range of China’s regulatory requirements. It is concluded that heavy metals can be properly stabilized in LWA samples containing sludge and cannot be easily released into the environment again to cause secondary pollution. PMID:25961800

Leachability of heavy metals from lightweight aggregates made with sewage sludge and municipal solid waste incineration fly ash.

PubMed

Wei, Na

2015-05-07

Lightweight aggregate (LWA) production with sewage sludge and municipal solid waste incineration (MSWI) fly ash is an effective approach for waste disposal. This study investigated the stability of heavy metals in LWA made from sewage sludge and MSWI fly ash. Leaching tests were conducted to find out the effects of MSWI fly ash/sewage sludge (MSWI FA/SS) ratio, sintering temperature and sintering time. It was found that with the increase of MSWI FA/SS ratio, leaching rates of all heavy metals firstly decreased and then increased, indicating the optimal ratio of MSWI fly ash/sewage sludge was 2:8. With the increase of sintering temperature and sintering time, the heavy metal solidifying efficiencies were strongly enhanced by crystallization and chemical incorporations within the aluminosilicate or silicate frameworks during the sintering process. However, taking cost-savings and lower energy consumption into account, 1100 °C and 8 min were selected as the optimal parameters for LWA sample- containing sludge production. Furthermore, heavy metal leaching concentrations under these optimal LWA production parameters were found to be in the range of China's regulatory requirements. It is concluded that heavy metals can be properly stabilized in LWA samples containing sludge and cannot be easily released into the environment again to cause secondary pollution.

Effects of fluoride residue on thermal stability in Cu/porous low-k interconnects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kobayashi, Y.; Ozaki, S.; Nakamura, T.

2014-06-19

We have investigated the effects of fluoride residue on the thermal stability of a Cu/barrier metal (BM)/porous low-k film (k < 2.3) structure. We confirmed that the Cu agglomerated more on a BM/inter layer dielectric (ILD) with a fluoride residue. To consider the effect of fluoride residue on Cu agglomeration, the structural state at the Cu/BM interface was evaluated with a cross-section transmission electron microscope (TEM) and atomic force microscope (AFM). In addition, the chemical bonding state at the Cu/BM interface was evaluated with the interface peeling-off method and X-ray photoelectron spectroscopy (XPS). Moreover, we confirmed the ionization of fluoridemore » residue and oxidation of Cu with fluoride and moisture to clarify the effect of fluoride residue on Cu. Our experimental results indicated that the thermal stability in Cu/porous low-k interconnects was degraded by enhancement of Cu oxidation with fluoride ions diffusion as an oxidizing catalyst.« less

Powder free PECVD epitaxial silicon by plasma pulsing or increasing the growth temperature

NASA Astrophysics Data System (ADS)

Chen, Wanghua; Maurice, Jean-Luc; Vanel, Jean-Charles; Cabarrocas, Pere Roca i.

2018-06-01

Crystalline silicon thin films are promising candidates for low cost and flexible photovoltaics. Among various synthesis techniques, epitaxial growth via low temperature plasma-enhanced chemical vapor deposition is an interesting choice because of two low temperature related benefits: low thermal budget and better doping profile control. However, increasing the growth rate is a tricky issue because the agglomeration of clusters required for epitaxy leads to powder formation in the plasma. In this work, we have measured precisely the time evolution of the self-bias voltage in silane/hydrogen plasmas at millisecond time scale, for different values of the direct-current bias voltage applied to the radio frequency (RF) electrode and growth temperatures. We demonstrate that the decisive factor to increase the epitaxial growth rate, i.e. the inhibition of the agglomeration of plasma-born clusters, can be obtained by decreasing the RF OFF time or increasing the growth temperature. The influence of these two parameters on the growth rate and epitaxial film quality is also presented.

Toxicity of boehmite nanoparticles: impact of the ultrafine fraction and of the agglomerates size on cytotoxicity and pro-inflammatory response.

PubMed

Forest, Valérie; Pailleux, Mélanie; Pourchez, Jérémie; Boudard, Delphine; Tomatis, Maura; Fubini, Bice; Sennour, Mohamed; Hochepied, Jean-François; Grosseau, Philippe; Cottier, Michèle

2014-08-01

Boehmite (γ-AlOOH) nanoparticles (NPs) are used in a wide range of industrial applications. However, little is known about their potential toxicity. This study aimed at a better understanding of the relationship between the physico-chemical properties of these NPs and their in vitro biological activity. After an extensive physico-chemical characterization, the cytotoxicity, pro-inflammatory response and oxidative stress induced by a bulk industrial powder and its ultrafine fraction were assessed using RAW264.7 macrophages. Although the bulk powder did not trigger a significant biological activity, pro-inflammatory response was highly enhanced with the ultrafine fraction. This observation was confirmed with boehmite NPs synthesized at the laboratory scale, with well-defined and tightly controlled physico-chemical features: toxicity was increased when NPs were dispersed. In conclusion, the agglomerates size of boehmite NPs has a major impact on their toxicity, highlighting the need to study not only raw industrial powders containing NPs but also the ultrafine fractions representative of respirable particles.

Combustion characteristics and arsenic retention during co-combustion of agricultural biomass and bituminous coal.

PubMed

Zhou, Chuncai; Liu, Guijian; Wang, Xudong; Qi, Cuicui; Hu, Yunhu

2016-08-01

A combination of thermogravimetric analysis (TG) and laboratory-scale circulated fluidized bed combustion experiment was conducted to investigate the thermochemical, kinetic and arsenic retention behavior during co-combustion bituminous coal with typical agricultural biomass. Results shown that ignition performance and thermal reactivity of coal could be enhanced by adding biomass in suitable proportion. Arsenic was enriched in fly ash and associated with fine particles during combustion of coal/biomass blends. The emission of arsenic decreased with increasing proportion of biomass in blends. The retention of arsenic may be attributed to the interaction between arsenic and fly ash components. The positive correlation between calcium content and arsenic concentration in ash suggesting that the arsenic-calcium interaction may be regarded as the primary mechanism for arsenic retention. Copyright © 2016 Elsevier Ltd. All rights reserved.

Man-made vitreous fiber produced from incinerator ash using the thermal plasma technique and application as reinforcement in concrete.

PubMed

Yang, Sheng-Fu; Wang, To-Mai; Lee, Wen-Cheng; Sun, Kin-Seng; Tzeng, Chin-Ching

2010-10-15

This study proposes using thermal plasma technology to treat municipal solid waste incinerator ashes. A feasible fiberization method was developed and applied to produce man-made vitreous fiber (MMVF) from plasma vitrified slag. MMVF were obtained through directly blending the oxide melt stream with high velocity compressed air. The basic technological characteristics of MMVF, including morphology, diameter, shot content, length and chemical resistance, are described in this work. Laboratory experiments were conducted on the fiber-reinforced concrete. The effects of fibrous content on compressive strength and flexural strength are presented. The experimental results showed the proper additive of MMVF in concrete can enhance its mechanical properties. MMVF products produced from incinerator ashes treated with the thermal plasma technique have great potential for reinforcement in concrete. 2010 Elsevier B.V. All rights reserved.

Mutations with epigenetic effects in myeloproliferative neoplasms and recent progress in treatment: Proceedings from the 5th International Post-ASH Symposium

PubMed Central

Tefferi, A; Abdel-Wahab, O; Cervantes, F; Crispino, J D; Finazzi, G; Girodon, F; Gisslinger, H; Gotlib, J; Kiladjian, J-J; Levine, R L; Licht, J D; Mullally, A; Odenike, O; Pardanani, A; Silver, R T; Solary, E; Mughal, T

2011-01-01

Immediately following the 2010 annual American Society of Hematology (ASH) meeting, the 5th International Post-ASH Symposium on Chronic Myelogenous Leukemia and BCR-ABL1-Negative Myeloproliferative Neoplasms (MPNs) took place on 7–8 December 2010 in Orlando, Florida, USA. During this meeting, the most recent advances in laboratory research and clinical practice, including those that were presented at the 2010 ASH meeting, were discussed among recognized authorities in the field. The current paper summarizes the proceedings of this meeting in BCR-ABL1-negative MPN. We provide a detailed overview of new mutations with putative epigenetic effects (TET oncogene family member 2 (TET2), additional sex comb-like 1 (ASXL1), isocitrate dehydrogenase (IDH) and enhancer of zeste homolog 2 (EZH2)) and an update on treatment with Janus kinase (JAK) inhibitors, pomalidomide, everolimus, interferon-α, midostaurin and cladribine. In addition, the new ‘Dynamic International Prognostic Scoring System (DIPSS)-plus' prognostic model for primary myelofibrosis (PMF) and the clinical relevance of distinguishing essential thrombocythemia from prefibrotic PMF are discussed. PMID:23471017

Compressive strength and interfacial transition zone of sugar cane bagasse ash concrete: A comparison to the established pozzolans

NASA Astrophysics Data System (ADS)

Hussein, Asma Abd Elhameed; Shafiq, Nasir; Nuruddin, Muhd Fadhil

2015-05-01

Agricultural and industrial by-products are commonly used in concrete production as cement replacement materials (CRMs) or as admixtures to enhance both fresh and hardened properties of concrete as well as to save the environment from the negative effects caused by their disposal. Sugar Cane Bagasse Ash (SCBA) is one of the promising CRMs, it is used as a partial replacement of cement for producing concrete; properties of such concrete depend on the chemical composition, fineness, and burning temperature of SCBA. Approximately 1500 Million tons of sugarcane are annually produced over all the world which leave about 40-45% bagasse after juice crushing for sugar industry giving an average annual production of about 600 Million tons of bagasse as a waste material. This paper presents some findings on the effect of SCBA on workability, compressive strength and microstructure of interfacial zone of concrete and its performance is compared to some of the established CRMs namely Densified Silica Fume, Fly Ash and Microwave Incinerated Rice Husk Ash.

The effect of nano-silica fertilizer concentration and rice hull ash doses on soybean (Glycine max (L.) Merrill) growth and yield

NASA Astrophysics Data System (ADS)

Suciaty, T.; Purnomo, D.; Sakya, A. T.; Supriyadi

2018-03-01

Agriculture is facing a number of challenges included limited water supply, low nutrient use efficiency, etc affected by climate change. Nano-silica is a product of nanotechnology, the frontier technologies to enhance crop productivity under climate change threats. The purpose of the research was to investigate the effects of nano silica concentration and rice hull ash on growth and yield of soybean. The experiment was conducted at Gagasari village, Cirebon, West Java from March until June 2017. The treatments were arranged by using factorial completely randomized block design with two factors. The first factor was a concentration of nano silica fertilizer consisted of four levels i.e., 0, 1.75, 2.5, and 3.75 ml.l‑1. The second factor was doses of rice hull ash consisted of four levels i.e., 0, 1, 2, and 3 ton.ha‑1. Each treatment combinations was repeated three times. The result showed that concentration of nano silica individually affected the number of leaves and number of branches, NAR and RGR, productive branches at 21, 30-45, and 35 daps, respectively. It also affected the seed dry weight plant‑1 and plot‑1. Meanwhile, doses of rice hull ash affected LAI, NAR, and RGR, 15-30, and 30-45 dap, respectively. Dry seed weight plot‑1 was also affected by doses of rice hull ash. There was an interaction effect between nano-silica concentration and doses of rice hull ash on number pods.plant‑1. Combinations of 2.5 ml.l‑1 nano-silica and 3 ton.ha‑1 of rice hull ash gave the highest number pods.plant‑1.

Volcanic ash and aviation–The challenges of real-time, global communication of a natural hazard

USGS Publications Warehouse

Lechner, Peter; Tupper, Andrew C.; Guffanti, Marianne C.; Loughlin, Sue; Casadevall, Thomas

2017-01-01

More than 30 years after the first major aircraft encounters with volcanic ash over Indonesia in 1982, it remains challenging to inform aircraft in flight of the exact location of potentially dangerous ash clouds on their flight path, particularly shortly after the eruption has occurred. The difficulties include reliably forecasting and detecting the onset of significant explosive eruptions on a global basis, observing the dispersal of eruption clouds in real time, capturing their complex structure and constituents in atmospheric transport models, describing these observations and modelling results in a manner suitable for aviation users, delivering timely warning messages to the cockpit, flight planners and air traffic management systems, and the need for scientific development in order to undertake operational enhancements. The framework under which these issues are managed is the International Airways Volcano Watch (IAVW), administered by the International Civil Aviation Organization (ICAO). ICAO outlines in its standards and recommended practices (International Civil Aviation Organization, 2014) the basic volcanic monitoring and communication that is necessary at volcano observatories in Member States (countries). However, not all volcanoes are monitored and not all countries with volcanoes have mandated volcano observatories or equivalents. To add to the efforts of volcano observatories, a system of Meteorological Watch Offices, Air Traffic Management Area Control Centres, and nine specialist Volcanic Ash Advisory Centres (VAACs) are responsible for observing, analysing, forecasting and communicating the aviation hazard (airborne ash), using agreed techniques and messages in defined formats. Continuous improvement of the IAVW framework is overseen by expert groups representing the operators of the system, the user community, and the science community. The IAVW represents a unique marriage of two scientific disciplines - volcanology and meteorology - with the aviation user community. There have been many multifaceted volcanic eruptions in complex meteorological conditions during the history of the IAVW. Each new eruption brings new insights into how the warning system can be improved, and each reinforces the lessons that have gone before. The management of these events has improved greatly since the major ash encounters in the 1980s, but discontinuities in the warning and communications system still occur. A good example is a 2014 ash encounter over Indonesia following the eruption of Kelut where the warnings did not reach the aircraft crew. Other events present enormous management challenges – for example the 2010 Eyjafjallajökull eruption in Iceland was, overall, less hazardous than many less publicised eruptions, but numerous small to moderate explosions over several weeks produced widespread disruption and a large economic impact. At the time of writing, while there has been hundreds of millions of US dollars in damage to aircraft from encounters with ash, there have been no fatalities resulting from aviation incidents in, or proximal to volcanic ash cloud. This reflects, at least in part, the hard work done in putting together a global warning system - although to some extent it also reflects a measure of good statistical fortune. In order to minimise the risk of aircraft encounters with volcanic ash clouds, the global effort continues. The future priorities for the IAVW are strongly focused on enhancing communication before, and at the very onset of a volcanic ash-producing event (typically the more dangerous stage), together with improved downstream information and warning systems to help reduce the economic impact of eruptions on aviation.

A Critical Study of Agglomerated Multigrid Methods for Diffusion

NASA Technical Reports Server (NTRS)

Nishikawa, Hiroaki; Diskin, Boris; Thomas, James L.

2011-01-01

Agglomerated multigrid techniques used in unstructured-grid methods are studied critically for a model problem representative of laminar diffusion in the incompressible limit. The studied target-grid discretizations and discretizations used on agglomerated grids are typical of current node-centered formulations. Agglomerated multigrid convergence rates are presented using a range of two- and three-dimensional randomly perturbed unstructured grids for simple geometries with isotropic and stretched grids. Two agglomeration techniques are used within an overall topology-preserving agglomeration framework. The results show that multigrid with an inconsistent coarse-grid scheme using only the edge terms (also referred to in the literature as a thin-layer formulation) provides considerable speedup over single-grid methods but its convergence deteriorates on finer grids. Multigrid with a Galerkin coarse-grid discretization using piecewise-constant prolongation and a heuristic correction factor is slower and also grid-dependent. In contrast, grid-independent convergence rates are demonstrated for multigrid with consistent coarse-grid discretizations. Convergence rates of multigrid cycles are verified with quantitative analysis methods in which parts of the two-grid cycle are replaced by their idealized counterparts.

A Critical Study of Agglomerated Multigrid Methods for Diffusion

NASA Technical Reports Server (NTRS)

Thomas, James L.; Nishikawa, Hiroaki; Diskin, Boris

2009-01-01

Agglomerated multigrid techniques used in unstructured-grid methods are studied critically for a model problem representative of laminar diffusion in the incompressible limit. The studied target-grid discretizations and discretizations used on agglomerated grids are typical of current node-centered formulations. Agglomerated multigrid convergence rates are presented using a range of two- and three-dimensional randomly perturbed unstructured grids for simple geometries with isotropic and highly stretched grids. Two agglomeration techniques are used within an overall topology-preserving agglomeration framework. The results show that multigrid with an inconsistent coarse-grid scheme using only the edge terms (also referred to in the literature as a thin-layer formulation) provides considerable speedup over single-grid methods but its convergence deteriorates on finer grids. Multigrid with a Galerkin coarse-grid discretization using piecewise-constant prolongation and a heuristic correction factor is slower and also grid-dependent. In contrast, grid-independent convergence rates are demonstrated for multigrid with consistent coarse-grid discretizations. Actual cycle results are verified using quantitative analysis methods in which parts of the cycle are replaced by their idealized counterparts.

Friction Stir Welding of Al Alloy 2219-T8: Part II-Mechanical and Corrosion

NASA Astrophysics Data System (ADS)

Kang, Ju; Feng, Zhi-Cao; Li, Ji-Chao; Frankel, G. S.; Wang, Guo-Qing; Wu, Ai-Ping

2016-09-01

In Part I of this series, abnormal agglomerations of θ particles with size of about 100 to 1000 µm were observed in friction stir welded AA2219-T8 joints. In this work, the effects of these agglomerated θ particles on the mechanical and corrosion properties of the joints are studied. Tensile testing with in situ SEM imaging was utilized to monitor crack initiation and propagation in base metal and weld nugget zone (WNZ) samples. These tests showed that cracks initiated in the θ particles and at the θ/matrix interfaces, but not in the matrix. The WNZ samples containing abnormal agglomerated θ particles had a similar ultimate tensile stress but 3 pct less elongation than other WNZ samples with only normal θ particles. Measurements using the microcell technique indicated that the agglomerated θ particles acted as a cathode causing the dissolution of adjacent matrix. The abnormal θ particle agglomerations led to more severe localized attack due to the large cathode/anode ratio. Al preferential dissolution occurred in the abnormal θ particle agglomerations, which was different from the corrosion behavior of normal size θ particles.

Dynamic forces on agglomerated particles caused by high-intensity ultrasound.

PubMed

Knoop, Claas; Fritsching, Udo

2014-03-01

In this paper the acoustic forces on particles and agglomerates caused by high-intensity ultrasound in gaseous atmosphere are derived by means of computational fluid dynamics (CFD). Sound induced forces cause an oscillating stress scenario where the primary particles of an agglomerate are alternatingly pressed together and torn apart with the frequency of the applied wave. A comparison of the calculated acoustic forces with respect to the inter particle adhesion forces from Van-der-Waals and liquid bridge interactions reveals that the separation forces may reach the same order of magnitude for 80 μm sized SiO2-particles. Hence, with finite probability acoustically agitated gases may de-agglomerate/disperse solid agglomerate structures. This effect is confirmed by dispersion experiments in an acoustic particle levitation setup. Copyright © 2013 Elsevier B.V. All rights reserved.

Attrition-enhanced sulfur capture by limestone particles in fluidized beds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saastamoinen, J.J.; Shimizu, T.

2007-02-14

Sulfur capture by limestone particles in fluidized beds is a well-established technology. The underlying chemical and physical phenomena of the process have been extensively studied and modeled. However, most of the studies have been focused on the relatively brief initial stage of the process, which extends from a few minutes to hours, yet the residence time of the particles in the boiler is much longer. Following the initial stage, a dense product layer will be formed on the particle surface, which decreases the rate of sulfur capture and the degree of utilization of the sorbent. Attrition can enhance sulfur capturemore » by removing this layer. A particle model for sulfur capture has been incorporated with an attrition model. After the initial stage, the rate of sulfur capture stabilizes, so that attrition removes the surface at the same rate as diffusion and chemical reaction produces new product in a thin surface layer of a particle. An analytical solution for the conversion of particles for this regime is presented. The solution includes the effects of the attrition rate, diffusion, chemical kinetics, pressure, and SO{sub 2} concentration, relative to conversion-dependent diffusivity and the rate of chemical reaction. The particle model results in models that describe the conversion of limestone in both fly ash and bottom ash. These are incorporated with the residence time (or reactor) models to calculate the average conversion of the limestone in fly ash and bottom ash, as well as the efficiency of sulfur capture. Data from a large-scale pressurized fluidized bed are compared with the model results.« less

Cost-effectiveness of conservation payment schemes for species with different range sizes.

PubMed

Drechsler, Martin; Smith, Henrik G; Sturm, Astrid; Wätzold, Frank

2016-08-01

Payments to compensate landowners for carrying out costly land-use measures that benefit endangered biodiversity have become an important policy instrument. When designing such payments, it is important to take into account that spatially connected habitats are more valuable for many species than isolated ones. One way to incentivize provision of connected habitats is to offer landowners an agglomeration bonus, that is, a bonus on top of payments they are receiving to conserve land if the land is spatially connected. Researchers have compared the cost-effectiveness of the agglomeration bonus with 2 alternatives: an all-or-nothing, agglomeration payment, where landowners receive a payment only if the conserved land parcels have a certain level of spatial connectivity, and a spatially homogeneous payment, where landowners receive a payment for conserved land parcels irrespective of their location. Their results show the agglomeration bonus is rarely the most cost-effective option, and when it is, it is only slightly better than one of the alternatives. This suggests that the agglomeration bonus should not be given priority as a policy design option. However, this finding is based on consideration of only 1 species. We examined whether the same applied to 2 species, one for which the homogeneous payment is best and the other for which the agglomeration payment is most cost-effective. We modified a published conceptual model so that we were able to assess the cost-effectiveness of payment schemes for 2 species and applied it to a grassland bird and a grassland butterfly in Germany that require the same habitat but have different spatial-connectivity needs. When conserving both species, the agglomeration bonus was more cost-effective than the agglomeration and the homogeneous payment; thus, we showed that as a policy the agglomeration bonus is a useful conservation-payment option. © 2016 Society for Conservation Biology.

High shear mixing granulation of ibuprofen and beta-cyclodextrin: effects of process variables on ibuprofen dissolution.

PubMed

Ghorab, Mohamed K; Adeyeye, Moji Christianah

2007-10-19

The aims of the study were to evaluate the effect of high shear mixer (HSM) granulation process parameters and scale-up on wet mass consistency and granulation characteristics. A mixer torque rheometer (MTR) was employed to evaluate the granulating solvents used (water, isopropanol, and 1:1 vol/vol mixture of both) based on the wet mass consistency. Gral 25 and mini-HSM were used for the granulation. The MTR study showed that the water significantly enhanced the beta-cyclodextrin (beta CD) binding tendency and the strength of liquid bridges formed between the particles, whereas the isopropanol/water mixture yielded more suitable agglomerates. Mini-HSM granulation with the isopropanol/water mixture (1:1 vol/vol) showed a reduction in the extent of torque value rise by increasing the impeller speed as a result of more breakdown of agglomerates than coalescence. In contrast, increasing the impeller speed of the Gral 25 resulted in higher torque readings, larger granule size, and consequently, slower dissolution. This was due to a remarkable rise in temperature during Gral granulation that reduced the isopropanol/water ratio in the granulating solvent as a result of evaporation and consequently increased the beta CD binding strength. In general, the HSM granulation retarded ibuprofen dissolution compared with the physical mixture because of densification and agglomeration. However, a successful HSM granulation scale-up was not achieved due to the difference in the solvent mixture's effect from 1 scale to the other.

The enrichment behavior of natural radionuclides in pulverized oil shale-fired power plants.

PubMed

Vaasma, Taavi; Kiisk, Madis; Meriste, Tõnis; Tkaczyk, Alan Henry

2014-12-01

The oil shale industry is the largest producer of NORM (Naturally Occurring Radioactive Material) waste in Estonia. Approximately 11-12 million tons of oil shale containing various amounts of natural radionuclides is burned annually in the Narva oil shale-fired power plants, which accounts for approximately 90% of Estonian electricity production. The radionuclide behavior characteristics change during the fuel combustion process, which redistributes the radionuclides between different ash fractions. Out of 24 operational boilers in the power plants, four use circulating fluidized bed (CFB) technology and twenty use pulverized fuel (PF) technology. Over the past decade, the PF boilers have been renovated, with the main objective to increase the efficiency of the filter systems. Between 2009 and 2012, electrostatic precipitators (ESP) in four PF energy blocks were replaced with novel integrated desulphurization technology (NID) for the efficient removal of fly ash and SO2 from flue gases. Using gamma spectrometry, activity concentrations and enrichment factors for the (238)U ((238)U, (226)Ra, (210)Pb) and (232)Th ((232)Th, (228)Ra) family radionuclides as well as (40)K were measured and analyzed in different PF boiler ash fractions. The radionuclide activity concentrations in the ash samples increased from the furnace toward the back end of the flue gas duct. The highest values in different PF boiler ash fractions were in the last field of the ESP and in the NID ash, where radionuclide enrichment factors were up to 4.2 and 3.3, respectively. The acquired and analyzed data on radionuclide activity concentrations in different PF boiler ashes (operating with an ESP and a NID system) compared to CFB boiler ashes provides an indication that changes in the fuel (oil shale) composition and boiler working parameters, as well as technological enhancements in Estonian oil shale fired power plants, have had a combined effect on the distribution patterns of natural radionuclides in the oil shale combustion products. Copyright © 2014 Elsevier Ltd. All rights reserved.

Selenium(IV) and (VI) sorption by soils surrounding fly ash management facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hyun, S.; Burns, P.E.; Murarka, I.

2006-11-15

Leachate derived from unlined coal ash disposal facilities is one of the most significant anthropogenic sources of selenium to the environment. To establish a practical framework for predicting transport of selenium in ash leachate, sorption of Se(IV) and Se(VI) from 1 mM CaSO{sub 4} was measured for 18 soils obtained down-gradient from three ash landfill sites and evaluated with respect to several soil properties. Furthermore, soil attenuation from lab-generated ash leachate and the effect of Ca{sup 2+} and SO{sub 4}{sup 2-} concentrations as well as pH on both Se(IV) and Se(VI) was quantified for a subset of soils. For bothmore » Se(IV) and Se(VI), pH combined with either percentage clay or dithionite-citrate-bicarbonate (DCB)-extractable Fe described {gt} 80% of the differences in sorption across all soils, yielding an easy approach for making initial predictions regarding site-specific selenium transport to sensitive water bodies. Se(IV) consistently exhibited an order of magnitude greater sorption than Se(VI). Selenium sorption was highest at lower pH values, with Se(IV) sorption decreasing at pH values above 6, whereas Se(VI) decreased over the entire pH range (2.5-10). Using these pH adsorption envelopes, the likely effect of ash leachate-induced changes in soil pore water pH with time on selenium attenuation by down gradient soils can be predicted. Selenium sorption increased with increasing Ca{sup 2+} concentrations while SO{sub 4}2- suppressed sorption well above enhancements by Ca{sup 2+}. Soil attenuation of selenium from ash leachates agreed well with sorption measured from 1 mM CaSO{sub 4}, indicating that 1 mM CaSO{sub 4} is a reasonable synthetic leachate for assessing selenium behavior at ash landfill sites.« less

Ash after forest fires. Effects on soil hydrology and erosion

NASA Astrophysics Data System (ADS)

Bodí, Merche B.

2013-04-01

Hillslopes were though to be most susceptible to enhanced hydro-geomorphological responses immediately following burning, with susceptibility declining during the first months or years depending on the soil and vegetation recovery. However, Cerdà (1998) found some indices in that immediately after the fire, the thin wettable ash layer that typically covers the ground could absorb rainfall and prevent or delay the onset of overland flow and associated erosion. Therefore the time lag while ash remains on the ground become of crucial importance to protect the soil after a wildfire. The effect of this ash layer was rarely been considered in detail because ash has often been reduced or redistributed by wind or water erosion before the onset of monitoring and thus the data collection typically begun some weeks or month after the fire. The first papers focussed only on ash and its hydrological effects were published by Cerdà and Doerr (2008) and by Woods and Balfour (2008). The results showed that the soil covered with ash indeed reduced and delayed surface runoff, reduced soil splash detachment and produced lower sediment yield compared to bare terrain. However, these findings arose more questions, as for instance: Why in other research there were indices that ash reduces infiltration? what is the mechanism by which why ash reduces overland flow? The research went further with Bodí PhD. First of all, it was crucial the agreement on the fact that the material "ash" is very variable depending on the original vegetation and the type and temperature of combustion. Therefore ash properties are different between wildfires even and within a fire. This is the main reason of its different effects and thus ash not always reduces runoff and sediment yield. In this way, depending on the nature of ash, it can increase overland flow if it is crusted (usually it contains a high content of calcium carbonate), it is water repellent (with high contents of organic carbon and specially from certain Eucaliptus and Pinus), or if clog soil pores (depending also on the soil type). If ash is wettable, it can store even 80% of its volume and then it will delay and reduce overland flow proportionally to the thickness of the ash layer. Once ash gets saturated, the flow tends to adjust to an infiltration rate similar to the soil itself, or sometimes higher due to the protection of ash that can reduce soil water repellency and soil sealing (Bodí et al. 2011, 2012). Still, many other aspects on ash remain unknown and ash present us more questions like, what it is its role on the carbon cycle? what is the extent of the ahs effects at basin scale? what is the fate of ash and how long it remains in the ecosystem? are there specific effects of ash depending on the ecosystem and so the type of ash? Acknowledgements This work was supported financially by a research fellowship (AP2007-04602) from the Spanish Ministry of Science and Innovation (M.B. Bodí) and the projects PT2009-0073 and CGL2010-21670-C02-01. References Bodí, M.B., Mataix-Solera, J., Doerr, S.H., Cerdà, A., 2011, The wettability of ash from burned vegetation and its relationship to Mediterranean plant species type, burn severity and total organic carbon content. Geoderma 160, 599-607. Bodí, M.B., Doerr, S.H., Cerdà, A., Mataix-Solera, J., 2012, Hydrological effects of a layer of vegetation ash on underlying wettable and water repellent soil. Geoderma 191, 14-23 Cerdà, A., 1998, Changes in overland flow and infiltration after a rangeland fire in a Mediterranean scrubland. Hydrological Processes 12, 1031-1042. Cerdà, A., Doerr, S.H., 2008, The effect of ash and needle cover on surface runoff and erosion in the immediate post-fire period. Catena 74, 256-263. Woods, S.W., Balfour, V., 2008, The effect of ash on runoff and erosion after a forest wildfire, Montana, U.S.A. International Journal of Wildland Fire 17, 535-548.

Electrostatic formation of liquid marbles and agglomerates

NASA Astrophysics Data System (ADS)

Liyanaarachchi, K. R.; Ireland, P. M.; Webber, G. B.; Galvin, K. P.

2013-07-01

We report observations of a sudden, explosive release of electrostatically charged 100 μm glass beads from a particle bed. These cross an air gap of several millimeters, are engulfed by an approaching pendant water drop, and form a metastable spherical agglomerate on the bed surface. The stability transition of the particle bed is explained by promotion of internal friction by in-plane electrostatic stresses. The novel agglomerates formed this way resemble the "liquid marbles" formed by coating a drop with hydrophobic particles. Complex multi-layered agglomerates may also be produced by this method, with potential industrial, pharmaceutical, environmental, and biological applications.

Evaluation of an enhanced gravity-based fine-coal circuit for high-sulfur coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohanty, M.K.; Samal, A.R.; Palit, A.

One of the main objectives of this study was to evaluate a fine-coal cleaning circuit using an enhanced gravity separator specifically for a high sulfur coal application. The evaluation not only included testing of individual unit operations used for fine-coal classification, cleaning and dewatering, but also included testing of the complete circuit simultaneously. At a scale of nearly 2 t/h, two alternative circuits were evaluated to clean a minus 0.6-mm coal stream utilizing a 150-mm-diameter classifying cyclone, a linear screen having a projected surface area of 0.5 m{sup 2}, an enhanced gravity separator having a bowl diameter of 250 mmmore » and a screen-bowl centrifuge having a bowl diameter of 500 mm. The cleaning and dewatering components of both circuits were the same; however, one circuit used a classifying cyclone whereas the other used a linear screen as the classification device. An industrial size coal spiral was used to clean the 2- x 0.6-mm coal size fraction for each circuit to estimate the performance of a complete fine-coal circuit cleaning a minus 2-mm particle size coal stream. The 'linear screen + enhanced gravity separator + screen-bowl circuit' provided superior sulfur and ash-cleaning performance to the alternative circuit that used a classifying cyclone in place of the linear screen. Based on these test data, it was estimated that the use of the recommended circuit to treat 50 t/h of minus 2-mm size coal having feed ash and sulfur contents of 33.9% and 3.28%, respectively, may produce nearly 28.3 t/h of clean coal with product ash and sulfur contents of 9.15% and 1.61 %, respectively.« less

Mechanical particle coating using polymethacrylate nanoparticle agglomerates for the preparation of controlled release fine particles: The relationship between coating performance and the characteristics of various polymethacrylates.

PubMed

Kondo, Keita; Kato, Shinsuke; Niwa, Toshiyuki

2017-10-30

We aimed to understand the factors controlling mechanical particle coating using polymethacrylate. The relationship between coating performance and the characteristics of polymethacrylate powders was investigated. First, theophylline crystals were treated using a mechanical powder processor to obtain theophylline spheres (<100μm). Second, five polymethacrylate latexes were powdered by spray freeze drying to produce colloidal agglomerates. Finally, mechanical particle coating was performed by mixing theophylline spheres and polymethacrylate agglomerates using the processor. The agglomerates were broken under mechanical stress to coat the spheres effectively. The coating performance of polymethacrylate agglomerates tended to increase as their pulverization progressed. Differences in the grindability of the agglomerates were attributed to differences in particle structure, resulting from consolidation between colloidal particles. High-grindability agglomerates exhibited higher pulverization as their glass transition temperature (T g ) increased and the further pulverization promoted coating. We therefore conclude that the minimization of polymethacrylate powder by pulverization is an important factor in mechanical particle coating using polymethacrylate with low deformability. Meanwhile, when product temperature during coating approaches T g of polymer, polymethacrylate was soften to show high coating performance by plastic deformation. The effective coating by this mechanism may be accomplished by adjusting the temperature in the processor to the T g . Copyright © 2017 Elsevier B.V. All rights reserved.

Method of separating and de-watering fine particles

DOEpatents

Yoon, Roe-Hoan

2016-12-13

A process for cleaning and dewatering hydrophobic particulate materials is presented. The process is performed in two steps: 1) agglomeration of the hydrophobic particles in a first hydrophobic liquid/aqueous mixture; followed by 2) dispersion of the agglomerates in a second hydrophobic liquid to release the water trapped within the agglomerates along with the entrained hydrophilic particles.

Overpopulated, Underdeveloped Urban Agglomerations: Tomorrow’s Unstable Operating Environment

DTIC Science & Technology

2012-05-08

DATES COVERED (From - To) 4. TITLE AND SUBTITLE Overpopulated , Underdeveloped Urban Agglomerations: Tomorrow’s 5a. CONTRACT NUMBER...ABSTRACT This paper asserts that a unique future operational environment is developing: overpopulated , underdeveloped urban agglomerations. A...proposed definition for this operating environment is (or would be) an overpopulated urban area which is located within a developing or underdeveloped

Dehalogenation potential of municipal waste incineration fly ash. I. General principles.

PubMed

Pekárek, Vladimír; Karban, Jindrich; Fiserová, Eva; Bures, Michal; Pacáková, Vera; Vecerníková, Eva

2003-01-01

It is well known that the fly ash from filters of municipal waste incinerators (MWI-FA) shows dehalogenation properties after heating it to 240-450 degrees C. However, this property is not general, and fly ash samples do not possess dehalogenation ability at all in many cases. Fly ash has a very variable composition, and the state of the fly ash matter therefore plays the decisive role. In the present paper, the function of important components responsible for the dehalogenation activity of MWI-FA is analysed and compared with the model fly ash. With the aim of accounting for the dehalogenation activity of MWI-FA, the following studies of hexachlorobenzene (HCB) dechlorination were performed: The role of copper in dehalogenation experiments was evaluated for five types of metallic copper. The gasification of carbon in MWI-FA was studied in the 250-350 degrees C temperature range. Five different kinds of carbon were used, combined with conventional Cu(o) and activated nanosize copper powder. The dechlorination experiments were also carried out with Cu(II) compounds such as CuO, Cu(OH)2, CuCl2 and CuSO4. The results were discussed from the standpoint of thermodynamics of potential reactions. Based on these results, the model of fly ash was proposed, containing silica gel, metallic copper and carbon. The dechlorination ability of MWI-FA and the model fly ash are compared under oxygen-deficient atmosphere. The results show that, under given experimental conditions, copper acts in the dechlorination as a stoichiometric agent rather than as a catalyst. The increased surface activity of copper enhances its dechlorination activity. It was found further that the presence of copper leads to a decrease in the temperature of carbon gasification. The cyclic valence change from Cu(o) to Cu+ or Cu2+ is a prerequisite for the dehalogenation to take place. Thermodynamic analysis of the dechlorination effect, as well as the comparison of dechlorination pathways on MWI-FA and model fly ash, can provide a deeper understanding of the studied reaction.

Thermal Barrier Coatings Chemically and Mechanically Resistant to High Temperature Attack by Molten Ashes

NASA Astrophysics Data System (ADS)

Gledhill, Andrew

Thermal barrier coatings (TBCs) are ceramic coatings used on component in the hottest sections of gas turbine engines, used for power generation and aviation. These coatings insulate the underlying metal components and allow for much higher engine operating temperatures, improving the engine efficiency. These increase temperatures engender a new set of materials problems for TBCs. Operating temperatures in engines are now high enough for silicate impurities, either present in the fuel or ingested into the engines, to melt and adhere to the surface of the TBCs. The effects of four such impurities, two coal fly ashes, a petroleum coke-fly ash blend, and volcanic ash from the Eyjafjallajokull volcano were tested with conventional yttria-stabilized zirconia (YSZ) coatings, and found to penetrate through the entire thickness of the coating. This penetration reduces the strain tolerance of the coatings, and can result in premature failure. Testing on a newly built thermal gradient burner rig with simultaneous injection of ash impurities has shown a reduction of life up to 99.6% in these coatings when ash is present. Coatings of an alternative ceramic, gadolinium zirconate (Gd2Zr 2O7), were found to form a dense reaction layer with each of these impurities, preventing further penetration of the molten ash. This dense layer also reduces the strain tolerance, but these coatings were found to have a significantly higher life than the YSZ coatings. Testing with a small amount of ash baked onto the samples showed thirteen times the life of YSZ coatings. When the ash is continuously sprayed onto the hot sample, the life of the Gd2Zr2O7 coatings was nearly twice that of the YSZ. Finally, a delamination model was employed to explain the degradation of both types of coatings. This elastic model that takes into account the degree of penetration, differential cooling in thermal gradient testing, and thermal expansion mismatch with the underlying substrate, predicted the failure of YSZ coatings with the observed degree of penetration. The model shows that deposition optimization can be employed to further enhance the life of Gd 2Zr2O7coatings.

Degradation Mechanisms in Solid-Oxide Fuel and Electrolyzer Cells: Analytical Description of Nickel Agglomeration in a Ni /Y S Z Electrode

NASA Astrophysics Data System (ADS)

Kröll, L.; de Haart, L. G. J.; Vinke, I.; Eichel, R.-A.

2017-04-01

The microstructural evolution of a porous electrode consisting of a metal-ceramic matrix, consisting of nickel and yttria-stabilized zirconia (Y S Z ), is one of the main degradation mechanisms in a solid-oxide cell (SOC), in either fuel cell or electrolyzer mode. In that respect, the agglomeration of nickel particles in a SOC electrode leads to a decrease in the electronic conductivity as well as in the active catalytic area for the oxidation-reduction reaction of the fuel-water steam. An analytical model of the agglomeration behavior of a Ni /Y S Z electrode is proposed that allows for a quantitative description of the nickel agglomeration. The accuracy of the model is validated in terms of a comparison with experimental degradation measurements. The model is based on contact probabilities of nickel clusters in a porous network of nickel and Y S Z , derived from an algorithm of the agglomeration process. The iterative algorithm is converted into an analytical function, which involves structural parameters of the electrode, such as the porosity and the nickel content. Furthermore, to describe the agglomeration mechanism, the influence of the steam content and the flux rate are taken into account via reactions on the nickel surface. In the next step, the developed agglomeration model is combined with the mechanism of the Ostwald ripening. The calculated grain-size growth is compared to measurements at different temperatures and under low flux rates and low steam content, as well as under high flux rates and high steam content. The results confirm the necessity of connecting the two mechanisms and clarify the circumstances in which the single processes occur and how they contribute to the total agglomeration of the particles in the electrode.

Explore the influence of agglomeration on electrochemical performance of an amorphous MnO2/C composite by controlling drying process

NASA Astrophysics Data System (ADS)

Cui, Mangwei; Kang, Litao; Shi, Mingjie; Xie, Lingli; Wang, Xiaomin; Zhao, Zhe; Yun, Shan; Liang, Wei

2017-09-01

Amorphous MnO2/C composite is prepared by a facile redox reaction between potassium permanganate (KMnO4) and commercial black pen ink. Afterwards, two different drying processes, air drying or freeze drying, are employed to adjust the agglomeration state of particles in samples and explore its influence on capacitive performance. Experimental results indicate that the air-dried sample demonstrates much better cycling stability than the freeze-dried one (capacity retention at 5000 cycles: 70.9 vs. 60.7%), probably because of the relatively strong agglomeration between particles in this sample. Nevertheless, strong agglomeration seems to deteriorate the specific capacitance (from 492 down to 440.5 F/g at 1 A/g) due to the decrease of porosity and specific surface area. This study suggests that agglomeration of primary particles plays an important role to balance the specific capacitance and cycling stability for electrode materials.

Enhanced Dispersion of TiO2 Nanoparticles in a TiO2/PEDOT:PSS Hybrid Nanocomposite via Plasma-Liquid Interactions

NASA Astrophysics Data System (ADS)

Liu, Yazi; Sun, Dan; Askari, Sadegh; Patel, Jenish; Macias-Montero, Manuel; Mitra, Somak; Zhang, Richao; Lin, Wen-Feng; Mariotti, Davide; Maguire, Paul

2015-10-01

A facile method to synthesize a TiO2/PEDOT:PSS hybrid nanocomposite material in aqueous solution through direct current (DC) plasma processing at atmospheric pressure and room temperature has been demonstrated. The dispersion of the TiO2 nanoparticles is enhanced and TiO2/polymer hybrid nanoparticles with a distinct core shell structure have been obtained. Increased electrical conductivity was observed for the plasma treated TiO2/PEDOT:PSS nanocomposite. The improvement in nanocomposite properties is due to the enhanced dispersion and stability in liquid polymer of microplasma treated TiO2 nanoparticles. Both plasma induced surface charge and nanoparticle surface termination with specific plasma chemical species are proposed to provide an enhanced barrier to nanoparticle agglomeration and promote nanoparticle-polymer binding.

Sewage treatment method and apparatus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Engelmann, J.A.

1982-07-13

A method and apparatus for treating sewage and converting the sewage into organic fertilizer which utilizes equipment for converting the solid material of the sewage into patties and a mixing apparatus for mixing the patties with bulking agents. The mixture of patties and bulking agents is stored in a pile and subjected to a supply of air to enhance the self-combustion or oxidation of the organic material in the patties. The bulking agents provide the patty-bulking agent mixture with air passages and pockets and minimize compaction of the patties. The selfcombustion of the patties continues until the organic material ismore » burned out, leaving a residual ash. A shaker separator having an elongated longitudinal perforated member is reciprocated to separate the ash from the bulking agents. The ash is collected and utilized as organic fertilizer. The bulking agents are recycled back to the mixing apparatus.« less

Properties of concrete containing ground palm oil fuel ash as fine aggregate replacement

NASA Astrophysics Data System (ADS)

Saffuan, W. A.; Muthusamy, K.; Salleh, N. A. Mohd; Nordin, N.

2017-11-01

Environmental degradation resulting from increasing sand mining activities and disposal of palm oil fuel ash (POFA), a solid waste generated from palm oil mill needs to be resolved. Thus, the present research investigates the effect of ground palm oil fuel ash as partial fine aggregate replacement on workability, compressive and flexural strength of concrete. Five mixtures of concrete containing POFA as partial sand replacement designed with 0%, 10%, 20%, 30% and 40% of POFA by the weight of sand were used in this experimental work. The cube and beam specimens were casted and water cured up to 28 days before subjected to compressive strength and flexural strength testing respectively. Finding shows that concrete workability reduces as the amount of POFA added become larger. It is worth to note that 10% of POFA is the best amount to be used as partial fine aggregate replacement to produce concrete with enhanced strength.

Volcanic ash layers illuminate the resilience of Neanderthals and early modern humans to natural hazards.

PubMed

Lowe, John; Barton, Nick; Blockley, Simon; Ramsey, Christopher Bronk; Cullen, Victoria L; Davies, William; Gamble, Clive; Grant, Katharine; Hardiman, Mark; Housley, Rupert; Lane, Christine S; Lee, Sharen; Lewis, Mark; MacLeod, Alison; Menzies, Martin; Müller, Wolfgang; Pollard, Mark; Price, Catherine; Roberts, Andrew P; Rohling, Eelco J; Satow, Chris; Smith, Victoria C; Stringer, Chris B; Tomlinson, Emma L; White, Dustin; Albert, Paul; Arienzo, Ilenia; Barker, Graeme; Boric, Dusan; Carandente, Antonio; Civetta, Lucia; Ferrier, Catherine; Guadelli, Jean-Luc; Karkanas, Panagiotis; Koumouzelis, Margarita; Müller, Ulrich C; Orsi, Giovanni; Pross, Jörg; Rosi, Mauro; Shalamanov-Korobar, Ljiljiana; Sirakov, Nikolay; Tzedakis, Polychronis C

2012-08-21

Marked changes in human dispersal and development during the Middle to Upper Paleolithic transition have been attributed to massive volcanic eruption and/or severe climatic deterioration. We test this concept using records of volcanic ash layers of the Campanian Ignimbrite eruption dated to ca. 40,000 y ago (40 ka B.P.). The distribution of the Campanian Ignimbrite has been enhanced by the discovery of cryptotephra deposits (volcanic ash layers that are not visible to the naked eye) in archaeological cave sequences. They enable us to synchronize archaeological and paleoclimatic records through the period of transition from Neanderthal to the earliest anatomically modern human populations in Europe. Our results confirm that the combined effects of a major volcanic eruption and severe climatic cooling failed to have lasting impacts on Neanderthals or early modern humans in Europe. We infer that modern humans proved a greater competitive threat to indigenous populations than natural disasters.

Automated Selection of Hotspots (ASH): enhanced automated segmentation and adaptive step finding for Ki67 hotspot detection in adrenal cortical cancer.

PubMed

Lu, Hao; Papathomas, Thomas G; van Zessen, David; Palli, Ivo; de Krijger, Ronald R; van der Spek, Peter J; Dinjens, Winand N M; Stubbs, Andrew P

2014-11-25

In prognosis and therapeutics of adrenal cortical carcinoma (ACC), the selection of the most active areas in proliferative rate (hotspots) within a slide and objective quantification of immunohistochemical Ki67 Labelling Index (LI) are of critical importance. In addition to intratumoral heterogeneity in proliferative rate i.e. levels of Ki67 expression within a given ACC, lack of uniformity and reproducibility in the method of quantification of Ki67 LI may confound an accurate assessment of Ki67 LI. We have implemented an open source toolset, Automated Selection of Hotspots (ASH), for automated hotspot detection and quantification of Ki67 LI. ASH utilizes NanoZoomer Digital Pathology Image (NDPI) splitter to convert the specific NDPI format digital slide scanned from the Hamamatsu instrument into a conventional tiff or jpeg format image for automated segmentation and adaptive step finding hotspots detection algorithm. Quantitative hotspot ranking is provided by the functionality from the open source application ImmunoRatio as part of the ASH protocol. The output is a ranked set of hotspots with concomitant quantitative values based on whole slide ranking. We have implemented an open source automated detection quantitative ranking of hotspots to support histopathologists in selecting the 'hottest' hotspot areas in adrenocortical carcinoma. To provide wider community easy access to ASH we implemented a Galaxy virtual machine (VM) of ASH which is available from http://bioinformatics.erasmusmc.nl/wiki/Automated_Selection_of_Hotspots . The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_216.

Process and apparatus for coal hydrogenation

DOEpatents

Ruether, John A.; Simpson, Theodore B.

1991-01-01

In a coal liquefaction process an aqueous slurry of coal is prepared containing a dissolved liquefaction catalyst. A small quantity of oil is added to the slurry and then coal-oil agglomerates are prepared by agitation of the slurry at atmospheric pressure. The resulting mixture is drained of excess water and dried at atmospheric pressure leaving catalyst deposited on the agglomerates. The agglomerates then are fed to an extrusion device where they are formed into a continuous ribbon of extrudate and fed into a hydrogenation reactor at elevated pressure and temperature. The catalytic hydrogenation converts the extrudate primarily to liquid hydrocarbons in the reactor. The liquid drained in recovering the agglomerates is recycled.

In Situ Observations of Agglomeration of Non-metallic Inclusions at Steel/Ar and Steel/Slag Interfaces by High-Temperature Confocal Laser Scanning Microscope: A Review

NASA Astrophysics Data System (ADS)

Mu, Wangzhong; Dogan, Neslihan; Coley, Kenneth S.

2018-05-01

The agglomeration behavior of non-metallic inclusions in the steelmaking process is important for controlling the cleanliness of the steel. In this work, the observation of agglomeration behaviors of inclusions at steel/Ar and steel/slag interfaces using a high-temperature confocal laser scanning microscope (HT-CLSM) is summarized. This HT-CLSM technique has been applied to observe phase transformation during solidification and heat treatment and the engulfment and pushing behavior of inclusions in front of the solidified interface. In the current work, the inclusion agglomeration behavior at steel/Ar and steel/slag interfaces is summarized and discussed. Subsequently, the development of the theoretical work investigating inclusion agglomeration at steel/Ar and steel/slag interfaces including the initial capillary force model and Kralchevsky-Paunov model is described. Finally, the Kralchevsky-Paunov model is applied to investigating nitride inclusion agglomeration at high-manganese steel/Ar interfaces. This work aims to give a critical review of the application of HT-CLSM in secondary refining as well as a better control of inclusion elimination for clean steel production.

Influences of Different Components on Agglomeration Behavior of MoS2 During Oxidation Roasting Process in Air

NASA Astrophysics Data System (ADS)

Wang, Lu; Zhang, Guo-Hua; Wang, Jing-Song; Chou, Kuo-Chih

2016-08-01

An agglomeration of the furnace charge always takes place during the oxidation roasting process of molybdenite concentrate (with the main component of MoS2) in multiple hearth furnaces, which greatly affects the production process and furnace service life. In the present work, a preliminary study about the influence of various components on the agglomeration phenomenon of pure MoS2 have been carried out. The results show that reaction temperature, impurity content, and air flow rate have significant effects on the agglomeration extent. Meanwhile, the impurity type added into the pure MoS2 plays a crucial role. It was found that CaO and MgO have a stronger sulfur-fixing effect and that the desulphurization of the roasted product was uncompleted. It was also concluded that the agglomeration is due to the formation of low-melting-point eutectics, including that between MoO3 and impurities and that between MoO3 and Mo4O11. It is suggested that decreasing the impurities contents, especially K, Cu, Pb, and Fe, is an effective method for reducing the extent of agglomeration.

Effect of binder liquid type on spherical crystallization.

PubMed

Maghsoodi, Maryam; Hajipour, Ali

2014-11-01

Spherical crystallization is a process of formation of agglomerates of crystals held together by binder liquid. This research focused on understanding the effect of type of solvents used as binder liquid on the agglomeration of crystals. Carbamazepine and ethanol/water were used respectively as a model drug and crystallization system. Eight solvents as binder liquid including chloroform, dichloromethane, isopropyl acetate, ethyl acetate, n-hexane, dimethyl aniline, benzene and toluene were examined to better understand the relationship between the physical properties of the binder liquid and its ability to bring about the formation of the agglomerates. Moreover, the agglomerates obtained from effective solvents as binder liquid were evaluated in term of size, apparent particle density and compressive strength. In this study the clear trend was observed experimentally in the agglomerate formation as a function of physical properties of the binder liquid such as miscibility with crystallization system. Furthermore, the properties of obtained agglomerates such as size, apparent particle density and compressive strength were directly related to physical properties of effective binder liquids. RESULTS of this study offer a useful starting point for a conceptual framework to guide the selection of solvent systems for spherical crystallization.

Theranostic potential of gold nanoparticle-protein agglomerates

NASA Astrophysics Data System (ADS)

Sanpui, Pallab; Paul, Anumita; Chattopadhyay, Arun

2015-11-01

Owing to the ever-increasing applications, glittered with astonishing success of gold nanoparticles (Au NPs) in biomedical research as diagnostic and therapeutic agents, the study of Au NP-protein interaction seems critical for maximizing their theranostic efficiency, and thus demands comprehensive understanding. The mutual interaction of Au NPs and proteins at physiological conditions may result in the aggregation of protein, which can ultimately lead to the formation of Au NP-protein agglomerates. In the present article, we try to appreciate the plausible steps involved in the Au NP-induced aggregation of proteins and also the importance of the proteins' three-dimensional structures in the process. The Au NP-protein agglomerates can potentially be exploited for efficient loading and subsequent release of various therapeutically important molecules, including anticancer drugs, with the unique opportunity of incorporating hydrophilic as well as hydrophobic drugs in the same nanocarrier system. Moreover, the Au NP-protein agglomerates can act as `self-diagnostic' systems, allowing investigation of the conformational state of the associated protein(s) as well as the protein-protein or protein-Au NP interaction within the agglomerates. Furthermore, the potential of these Au NP-protein agglomerates as a novel platform for multifunctional theranostic application along with exciting future-possibilities is highlighted here.

Geological and technological evaluation of gold-bearing mineral material after photo-electrochemical activation leaching

NASA Astrophysics Data System (ADS)

Manzyrev, DV

2017-02-01

The paper reports the lab test results on simulation of heap leaching of unoxidized rebellious ore extracted from deep levels of Pogromnoe open pit mine, with different flowsheets and photo-electrochemically activated solutions. It has been found that pre-treatment of rebellious ore particles -10 mm in size by photo-electrochemically activated solutions at the stage preceding agglomeration with the use of rich cyanide solutions enhances gold recovery by 6%.

A comparison between the four Geldart groups on the performance of a gas-phase annular fluidized bed photoreactor for volatile organic compound oxidation.

PubMed

Diniz, Leonardo Almeida; Hewer, Thiago Lewis Reis; Matsumoto, Danielle; Teixeira, Antonio Carlos Silva Costa

2018-05-07

Heterogeneous photocatalytic oxidation (PCO) is a widely studied alternative for the elimination of volatile organic compounds (VOC) in air. In this context, research on novel photoreactor arrangements to enhance PCO rates is desired. Annular fluidized bed photoreactors (AFBPR) have yielded prominent results when compared to conventional thin film reactors. However, very few works aimed at optimizing AFBPR operation. In this study, TiO 2 photocalytic agglomerates were synthesized and segregated in specific size distributions to behave as Geldart groups A, B, C, and D fluidization. The TiO 2 agglomerates were characterized by XRD, FTIR spectra, and N 2 adsorption. Photocatalyst performances were compared in a 10-mm gapped AFBPR for degrading the model pollutant methyl-ethyl-ketone (MEK), using a 254-nm radiation source. Geldart group C showed to be inadequate for AFBPR operation due to the short operation range between fluidization and elutriation. In all the cases, photocatalytic reaction rates were superior to sole UV photolysis. Group A and group B demonstrated the highest reaction rates. Considerations based on mass transfer suggested that the reasons were enhanced UV distribution within the bed at lower flow rates and superior catalyst surface area at higher flow rates. Results also revealed that groups A, B, and D perform equally per catalyst area within an AFBPR if the fluidization numbers (FN) are high enough.

On the visibility of airborne volcanic ash and mineral dust

NASA Astrophysics Data System (ADS)

Weinzierl, B.; Sauer, D. N.; Minikin, A.; Reitebuch, O.; Dahlkötter, F.; Mayer, B. C.; Emde, C.; Tegen, I.; Gasteiger, J.; Petzold, A.; Veira, A.; Kueppers, U.; Schumann, U.

2012-12-01

After the eruption of the Eyjafjalla volcano (Iceland) in April 2010 which caused the most extensive restrictions of the airspace over Europe since the end of World War II, the aviation safety concept of avoiding "visible ash", i.e. volcanic ash that can be seen by the human eye, was recommended. However so far, no clear definition of "visible ash" and no relation between the visibility of an aerosol layer and related aerosol mass concentrations are available. The goal of our study is to assess whether it is possible from the pilot's perspective in flight to detect the presence of volcanic ash and to distinguish between volcanic ash and other aerosol layers just by sight. In our presentation, we focus the comparison with other aerosols on aerosol types impacting aviation: Besides volcanic ash, dust storms are known to be avoided by aircraft. We use in-situ and lidar data as well photographs taken onboard the DLR research aircraft Falcon during the Saharan Mineral Dust Experiments (SAMUM) in 2006 and 2008 and during the Eyjafjalla volcanic eruption in April/May 2010. We complement this analysis with numerical modelling, using idealized radiative transfer simulations with the 3D Monte Carlo radiative transfer code MYSTIC for a variety of selected viewing geometries. Both aerosol types, Saharan mineral dust and volcanic ash, show an enhanced coarse mode (> 1 μm) aerosol concentration, but volcanic ash aerosol additionally contains a significant number of Aitken mode particles (< 150 nm). Volcanic ash is slightly more absorbing than mineral dust, and the spectral behaviour of the refractive index is slightly different. According to our simulations, these differences are not detectable just by human eye. Furthermore, our data show, that it is difficult to define a lower threshold for the visibility of an aerosol layer because the visual detectability depends on many parameters, including the thickness of the aerosol layer, the brightness and color contrast between the airborne aerosol layer and the background, the illumination, the particle size distribution and mass concentration, the wavelength-dependent light scattering and absorption by the aerosol layer, the human perception, etc. In addition, the optical depth along the line of sight through an aerosol layer is more important than just the (vertical) optical depth, which is measured, for example, by sun photometers or satellites. The results of our study are in particular interesting for the question on the visibility of volcanic ash. Our analyses of "visible ash" demonstrate that under clear sky conditions volcanic ash is visible already at concentrations far below what is currently considered as the upper limit for safe operation of an aircraft engine (2 mg m-3). The presence of a grayish-brown layer in the atmosphere does not unambiguously indicate the presence of volcanic ash. An uninformed observer is unlikely to identify an aged volcanic ash layer in his field of view without further information. The presence of clouds would make it even more complicated to visually detect volcanic ash. In regions with high background aerosol loading in the atmosphere from natural or anthropogenic influences, such as seen in large parts of Asia, the visual detection of volcanic ash as an additional contaminant will be substantially more difficult.

Effect of particle volume fraction on the settling velocity of volcanic ash particles: insights from joint experimental and numerical simulations

PubMed Central

Del Bello, Elisabetta; Taddeucci, Jacopo; de’ Michieli Vitturi, Mattia; Scarlato, Piergiorgio; Andronico, Daniele; Scollo, Simona; Kueppers, Ulrich; Ricci, Tullio

2017-01-01

Most of the current ash transport and dispersion models neglect particle-fluid (two-way) and particle-fluid plus particle-particle (four-way) reciprocal interactions during particle fallout from volcanic plumes. These interactions, a function of particle concentration in the plume, could play an important role, explaining, for example, discrepancies between observed and modelled ash deposits. Aiming at a more accurate prediction of volcanic ash dispersal and sedimentation, the settling of ash particles at particle volume fractions (ϕp) ranging 10−7-10−3 was performed in laboratory experiments and reproduced by numerical simulations that take into account first the two-way and then the four-way coupling. Results show that the velocity of particles settling together can exceed the velocity of particles settling individually by up to 4 times for ϕp ~ 10−3. Comparisons between experimental and simulation results reveal that, during the sedimentation process, the settling velocity is largely enhanced by particle-fluid interactions but partly hindered by particle-particle interactions with increasing ϕp. Combining the experimental and numerical results, we provide an empirical model allowing correction of the settling velocity of particles of any size, density, and shape, as a function of ϕp. These corrections will impact volcanic plume modelling results as well as remote sensing retrieval techniques for plume parameters. PMID:28045056

Effect of particle volume fraction on the settling velocity of volcanic ash particles: insights from joint experimental and numerical simulations.

PubMed

Del Bello, Elisabetta; Taddeucci, Jacopo; De' Michieli Vitturi, Mattia; Scarlato, Piergiorgio; Andronico, Daniele; Scollo, Simona; Kueppers, Ulrich; Ricci, Tullio

2017-01-03

Most of the current ash transport and dispersion models neglect particle-fluid (two-way) and particle-fluid plus particle-particle (four-way) reciprocal interactions during particle fallout from volcanic plumes. These interactions, a function of particle concentration in the plume, could play an important role, explaining, for example, discrepancies between observed and modelled ash deposits. Aiming at a more accurate prediction of volcanic ash dispersal and sedimentation, the settling of ash particles at particle volume fractions (ϕ p ) ranging 10 -7 -10 -3 was performed in laboratory experiments and reproduced by numerical simulations that take into account first the two-way and then the four-way coupling. Results show that the velocity of particles settling together can exceed the velocity of particles settling individually by up to 4 times for ϕ p  ~ 10 -3 . Comparisons between experimental and simulation results reveal that, during the sedimentation process, the settling velocity is largely enhanced by particle-fluid interactions but partly hindered by particle-particle interactions with increasing ϕ p . Combining the experimental and numerical results, we provide an empirical model allowing correction of the settling velocity of particles of any size, density, and shape, as a function of ϕ p . These corrections will impact volcanic plume modelling results as well as remote sensing retrieval techniques for plume parameters.

NOVEL BINDERS AND METHODS FOR AGGLOMERATION OF ORE

DOE Office of Scientific and Technical Information (OSTI.GOV)

S.K. Kawatra; T.C. Eisele; J.A. Gurtler

2004-04-01

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that willmore » work satisfactorily. Primary examples of this are copper heap leaching, where there are no binders that will work in the acidic environment encountered in this process, and advanced ironmaking processes, where binders must function satisfactorily over an extraordinarily large range of temperatures (from room temperature up to over 1200 C). As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching and advanced primary ironmaking.« less

The agglomeration state of nanoparticles can influence the mechanism of their cellular internalisation.

PubMed

Halamoda-Kenzaoui, Blanka; Ceridono, Mara; Urbán, Patricia; Bogni, Alessia; Ponti, Jessica; Gioria, Sabrina; Kinsner-Ovaskainen, Agnieszka

2017-06-26

Significant progress of nanotechnology, including in particular biomedical and pharmaceutical applications, has resulted in a high number of studies describing the biological effects of nanomaterials. Moreover, a determination of so-called "critical quality attributes", that is specific physicochemical properties of nanomaterials triggering the observed biological response, has been recognised as crucial for the evaluation and design of novel safe and efficacious therapeutics. In the context of in vitro studies, a thorough physicochemical characterisation of nanoparticles (NPs), also in the biological medium, is necessary to allow a correlation with a cellular response. Following this concept, we examined whether the main and frequently reported characteristics of NPs such as size and the agglomeration state can influence the level and the mechanism of NP cellular internalization. We employed fluorescently-labelled 30 and 80 nm silicon dioxide NPs, both in agglomerated and non-agglomerated form. Using flow cytometry, transmission electron microscopy, the inhibitors of endocytosis and gene silencing we determined the most probable routes of cellular uptake for each form of tested silica NPs. We observed differences in cellular uptake depending on the size and the agglomeration state of NPs. Caveolae-mediated endocytosis was implicated particularly in the internalisation of well dispersed silica NPs but with an increase of the agglomeration state of NPs a combination of endocytic pathways with a predominant role of macropinocytosis was noted. We demonstrated that the agglomeration state of NPs is an important factor influencing the level of cell uptake and the mechanism of endocytosis of silica NPs.

Sustained Hypoxia Elicits Competing Spinal Mechanisms of Phrenic Motor Facilitation

PubMed Central

Devinney, Michael J.; Nichols, Nicole L.

2016-01-01

Acute intermittent hypoxia (AIH) induces phrenic long-term facilitation (pLTF), a form of spinal motor plasticity. Competing mechanisms give rise to phrenic motor facilitation (pMF; a general term including pLTF) depending on the severity of hypoxia within episodes. In contrast, moderate acute sustained hypoxia (mASH) does not elicit pMF. By varying the severity of ASH and targeting competing mechanisms of pMF, we sought to illustrate why moderate AIH (mAIH) elicits pMF but mASH does not. Although mAIH elicits serotonin-dependent pLTF, mASH does not; thus, mAIH-induced pLTF is pattern sensitive. In contrast, severe AIH (sAIH) elicits pLTF through adenosine-dependent mechanisms, likely from greater extracellular adenosine accumulation. Because serotonin- and adenosine-dependent pMF interact via cross talk inhibition, we hypothesized that pMF is obscured because the competing mechanisms of pMF are balanced and offsetting during mASH. Here, we demonstrate the following: (1) blocking spinal A2A receptors with MSX-3 reveals mASH-induced pMF; and (2) sASH elicits A2A-dependent pMF. In anesthetized rats pretreated with intrathecal A2A receptor antagonist injections before mASH (PaO2 = 40–54 mmHg) or sASH (PaO2 = 25–36 mmHg), (1) mASH induced a serotonin-dependent pMF and (2) sASH induced an adenosine-dependent pMF, which was enhanced by spinal serotonin receptor inhibition. Thus, competing adenosine- and serotonin-dependent mechanisms contribute differentially to pMF depending on the pattern/severity of hypoxia. Understanding interactions between these mechanisms has clinical relevance as we develop therapies to treat severe neuromuscular disorders that compromise somatic motor behaviors, including breathing. Moreover, these results demonstrate how competing mechanisms of plasticity can give rise to pattern sensitivity in pLTF. SIGNIFICANCE STATEMENT Intermittent hypoxia elicits pattern-sensitive spinal plasticity and improves motor function after spinal injury or during neuromuscular disease. Specific mechanisms of pattern sensitivity in this form of plasticity are unknown. We provide evidence that competing mechanisms of phrenic motor facilitation mediated by adenosine 2A and serotonin 2 receptors are differentially expressed, depending on the pattern/severity of hypoxia. Understanding how these distinct mechanisms interact during hypoxic exposures differing in severity and duration will help explain interesting properties of plasticity, such as pattern sensitivity, and may help optimize therapies to restore motor function in patients with neuromuscular disorders that compromise movement. PMID:27466333

Comprehensive Examination of Bottom Ash, Soil Dust, and Direct Emissions and Aging of Laboratory Biomass Burning as Potential Sources of Ice Nucleating Particles

NASA Astrophysics Data System (ADS)

Polen, M.; Jahl, L.; Jahn, L.; Somers, J.; Sullivan, R. C.

2017-12-01

Recent laboratory and field studies have found that biomass burning can produce ice nucleating particles (INP) with varying efficiencies depending on fuel and burn conditions. Few studies have examined the ice nucleating potential of bottom ash, which has the potential to be lofted during intense burning events. To date, no publications have examined the impact of atmospheric aging or lofted soil particles on INP emitted from biomass burning. This study investigated each of these aspects through laboratory biomass fuel combustion studies. We burned a number of grasses from different locations, and collected filter samples of fresh and photochemically aged biomass burning aerosol, as well as bottom ash collected after the burn. Some burns included soil that the grasses grew in to test for the importance of soil dust to INP emissions lofting during intense fires. The composition and mixing state of the aerosol was determined using a suite of online and offline single-particle techniques. Our findings suggest that bottom ash is a relatively weak INP, but all samples froze consistently at -20 °C < T < -25 °C. We also found that oxidation of the biomass burning aerosol typically enhances ice nucleating activity over fresh, unaged particles, increasing the ice active site surface density by up to a factor of 3 at T = -25 °C. Lastly, the presence of soil dust can greatly enhance INP concentrations for biomass burning events with an increase in the freezing temperature spectrum by > 3 °C. Detailed analysis of these samples aims to provide a clearer understanding of what components of biomass burning increase the ambient concentrations of ice nucleation active particles, and how their ice nucleation properties evolve during atmospheric aging.

Heterogeneous photochemistry of oxalic acid on Mauritanian sand and Icelandic volcanic ash.

PubMed

Styler, Sarah A; Donaldson, D J

2012-08-21

Teragram quantities of crustal and volcanic aerosol are released into the atmosphere on an annual basis. Although these substrates contain photoactive metal oxides, little is known about the role that they may play in catalyzing the heterogeneous phototransformation of semivolatile organic species. In the present study, we have investigated oxalic acid photochemistry at the surface of Fe(2)O(3), TiO(2), Mauritanian sand, and Icelandic volcanic ash in the presence and absence of oxygen using a photochemical Knudsen cell reactor. Illumination of all sample types resulted in the production of gas-phase CO(2). In the case of Mauritanian sand, the production of gas-phase CO(2) scaled with the loss of surface oxalic acid. In the absence of oxygen, the production of CO(2) by the sand and ash films scaled with the absorption spectrum of iron oxalate, which suggests that the reaction is at least in part iron-mediated. The presence of oxygen suppressed CO(2) production at the Fe(2)O(3) surface, enhanced CO(2) production at the Mauritanian sand surface, and did not have a net effect upon CO(2) production at the Icelandic ash surface. These different oxygen dependencies imply that oxalic acid photochemistry at the authentic surfaces under study was not solely iron-mediated. Experiments at the TiO(2) surface, which showed enhanced CO(2) production from oxalic acid in the presence of oxygen, suggest that Ti-mediated photochemistry played an important role. In summary, these results provide evidence that solid-phase aerosol photochemistry may influence the atmospheric lifetime of oxalic acid in arid regions, where its removal via wet deposition is insignificant.

Spatial trends in S and Cl in ash leachates of the May 18th, 1980 eruption of Mt. St Helens

NASA Astrophysics Data System (ADS)

Ayris, Paul M.; Delmelle, Pierre; Durant, Adam J.; Damby, David E.; Maters, Elena C.

2014-05-01

It has long been known that surficial deposits of salts and acids on volcanic ash particles derive from interactions of ash with sulphur and halide species within the eruption plume and volcanic cloud. These compounds are mobilised as ash particles are wetted, and beneficial or detrimental environmental and health impacts may be induced where the most concentrated solutions are produced. However, limited mechanistic understanding of gas-ash interactions currently precludes prediction of the spatial distribution or variation in leachate chemistry and concentration following an eruption. Sampling and leachate analysis of freshly-fallen ash therefore offers the sole method by which such variations can be observed. Previous ash leachate studies often involve a limited number of ash samples, and utilise a 'one-dimensional' analysis that considers variation in terms of absolute distance from the source volcano. Here, we demonstrate that extensive sampling and a 'two-dimensional' analysis can uncover more complex spatial trends. We compiled over 358 leachate compositions from the May 18th 1980 eruption of Mt. St. Helens. Of the water-extracted leachates, only 95 compositions from ash sampled at 45 localities between 35 and 1129 km from the volcano are sufficiently documented to be retrospectively comparable. To consider the effects of intra-deposit variability, we calculated average concentrations of leachate data within 11×22 km grid cells across the region, and defined a data quality parameter to reflect confidence in the derived values. To investigate any dependence of leachate composition on the grain size distribution, we generated an interpolated map of geometric specific surface area variation across the deposit, normalising ash leachate data to the calculated specific surface area at the corresponding sampling location. The data treatment identifies S and Cl enrichments in proximal blast deposits; relatively constant Cl concentrations across the ashfall deposits; and a core region of depleted S concentrations in ashfall deposits between 240 and 400 km from the volcano, coinciding with the distal thickening of the deposit attributed to particle aggregation and enhanced fallout. Blast deposit enrichments can be attributed to pre-eruptive uptake of SO2 and HCl gases within the cryptodome, while ashfall deposit trends could reflect differences in the rates of HCl and SO2 uptake by ash, modified by in-plume aggregation processes. However, to validate and interpret such trends with greater confidence would have required a greater spatial density and temporal resolution of sampling, with comprehensive characterisation of the recovered ash and the surrounding deposit. In the future, rigorous study and sampling of equivalent extent to that in the aftermath of the historic Mt. St. Helens eruption is likely required to extend insight into processes affecting the spatial distribution of leachate chemistry.

Coal fly ash and lime addition enhances the rate and efficiency of decomposition of food waste during composting.

PubMed

Wong, Jonathan W-C; Fung, Shun On; Selvam, Ammaiyappan

2009-07-01

To evaluate the use of coal fly ash (CFA) on the decomposition efficiency of food waste, synthetic food waste was mixed with lime at 1.5% and 3% (equivalent to 0.94% and 1.88% CaCO(3), respectively), CFA at 5%, 10% and 15% with lime so as to achieve CaCO(3) equivalent of 1.88% and composted for 42 days in a thermophilic 20 l composter with two replicates each. Alkaline materials at 1.88% CaCO(3) equivalent successfully buffered the pH during the composting and enhanced the decomposition efficiency. When these buffering was achieved with CFA+lime, the composting period could be shortened to approximately 28 days compared with approximately 42 days in 3% lime. Organic decomposition in terms of CO(2) loss, carbon turnover and nitrogen transformation were significantly higher for treatments with 1.88% CaCO(3) equivalent. Nutrient transformations and compost maturity parameters indicated that addition of CFA (5-10%) with lime at 1.88% CaCO(3) equivalent enhances the decomposition efficiency and shortens the composting period by 35%.

Research approach and first results on agglomerate compaction in protoplanetary dust simulation in the Cloud Manipulation System

NASA Astrophysics Data System (ADS)

Vedernikov, Andrei; Blum, Jurgen; Ingo Von Borstel, Olaf; Schraepler, Rainer; Balapanov, Daniyar; Cecere, Anselmo

2016-07-01

Nanometre and micrometre-sized solid particles are ubiquitous in space and on Earth - from galaxies, interstellar space, protoplanetary and debris disks to planetary rings and atmospheres, planetary surfaces, comets, interplanetary space, Earth's atmosphere. Apparently, the most intriguing problem in the picture of the formation of planets is the transition from individual microscopic dust grains to kilometre-sized planetesimals. Revealing the mechanisms of this transition is one of the main tasks of the European Space Agency's project Interaction in Cosmic and Atmospheric Particle Systems (ICAPS). It was found that Brownian motion driven agglomeration could not provide the transition within reasonable time scale. As a result, at this stage top scientific goals shifted towards forced agglomeration and concentration of particles, targeting revealing the onset of compaction, experimental study of the evolution of fractal dimensions, size and mass distribution, occurrence of bouncing. The main tasks comprise 1) development of the rapid agglomeration model 2) development of the experimental facilities creating big fractal-type agglomerates from 10 to 1000 μm from a cloud of micrometre-size grains; 3) experimental realization of the rapid agglomeration in microgravity and ground conditions; and 4) in situ investigation of the morphology, mobility, mechanical and optical properties of the free-floating agglomerates, including investigation of thermophoresis, photophoresis of the agglomerates and of the two-phase flow phenomena. To solve the experimental part of the tasks we developed a Cloud Manipulation System, realized as a breadboard (CMS BB) for long duration microgravity platforms and a simplified laboratory version (CMS LV) mostly oriented on short duration microgravity and ground tests. The new system is based on the use of thermophoresis, most favourable for cloud manipulation without creating additional particle-particle forces in the cloud with a possibility of growing single agglomerate out of the whole cloud. The cloud manipulation system additionally provides temperature stabilization or, on the contrary, high temperature variation in the observation volume; formation of controlled temperature gradients, intensive three-dimensional periodic shear flow or three-dimensional gas density pulsations of the contraction-expansion type; application of electrostatic gradients including electro dynamic balancing; imposing of photophoretic force, etc. Their choice and/or combination depend upon particular experimental task. Experiments on forced agglomeration in short duration microgravity conditions of the Bremen drop tower succeeded in rapid growth of extended agglomerates, formation of complex three-dimensional cloud patterns, allowed observing controlled cloud displacement, cloud trapping, particle separation with respect to their electrical charge. The breadboard (CMS BB) and the laboratory version of the Cloud Manipulation System (CMS LV) are new types of scientific instrument with high scientific potential. ESA PRODEX program, the Belgian Federal Science Policy Office, DLR project 50WM1223, ZARM Drop Tower Operation and Service Company Ltd. are greatly acknowledged.

Superheated fuel injection for combustion of liquid-solid slurries

DOEpatents

Robben, F.A.

1984-10-19

A method and device are claimed for obtaining, upon injection, flash evaporation of a liquid in a slurry fuel to aid in ignition and combustion. The device is particularly beneficial for use of coal-water slurry fuels in internal combustion engines such as diesel engines and gas turbines, and in external combustion devices such as boilers and furnaces. The slurry fuel is heated under pressure to near critical temperature in an injector accumulator, where the pressure is sufficiently high to prevent boiling. After injection into a combustion chamber, the water temperature will be well above boiling point at a reduced pressure in the combustion chamber, and flash boiling will preferentially take place at solid-liquid surfaces, resulting in the shattering of water droplets and the subsequent separation of the water from coal particles. This prevents the agglomeration of the coal particles during the subsequent ignition and combustion process, and reduces the energy required to evaporate the water and to heat the coal particles to ignition temperature. The overall effect will be to accelerate the ignition and combustion rates, and to reduce the size of the ash particles formed from the coal. 2 figs., 2 tabs.

Analysis of hard coal quality for narrow size fraction under 20 mm

NASA Astrophysics Data System (ADS)

Niedoba, Tomasz; Pięta, Paulina

2018-01-01

The paper presents the results of an analysis of hard coal quality diversion in narrow size fraction by using taxonomic methods. Raw material samples were collected in selected mines of Upper Silesian Industrial Region and they were classified according to the Polish classification as types 31, 34.2 and 35. Then, each size fraction was characterized in terms of the following properties: density, ash content, calorific content, volatile content, total sulfur content and analytical moisture. As a result of the analysis it can be stated that the best quality in the entire range of the tested size fractions was the 34.2 coking coal type. At the same time, in terms of price parameters, high quality of raw material characterised the following size fractions: 0-6.3 mm of 31 energetic coal type and 0-3.15 mm of 35 coking coal type. The methods of grouping (Ward's method) and agglomeration (k-means method) have shown that the size fraction below 10 mm was characterized by higher quality in all the analyzed hard coal types. However, the selected taxonomic methods do not make it possible to identify individual size fraction or hard coal types based on chosen parameters.

Adsorption characteristics of arsenic from micro-polluted water by an innovative coal-based mesoporous activated carbon.

PubMed

Li, Wei-Guang; Gong, Xu-Jin; Wang, Ke; Zhang, Xin-Ran; Fan, Wen-Biao

2014-08-01

An innovative coal-based mesoporous activated carbon (NCPAC) was prepared by re-agglomeration, oxidation and two-step activation using coal-blending as precursor. Adsorption capacities of As(III) and As(V) ions (<0.5mg/L) onto NCPAC as a function of pH, adsorbent dose, initial arsenic concentrations, contact time, and adsorption isotherms at 7°C was investigated. The innovative methods promoted total pore volume (1.087cm(3)/g), mesoporosity (64.31%), iodine numbers (1104mg/g), methylene blue (251.8mg/g) and ash contents (15.26%). The adsorption capacities of NCPAC for As(III) and As(V) were found to be strongly dependent on pH and contact time. The optimal pH value was 6. The equilibrium time was 60min for adsorption of As(III) and As(V) by NCPAC. The Langmuir model fitted the experimental data well for both As(III) (R(2)=0.9980) and As(V) (R(2)=0.9988). Maximum adsorption capacities of As(III) and As(V) (C0=0.50mg/L) by NCPAC were 1.491 and 1.760mg/g, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

Magnetic agglomeration method for size control in the synthesis of magnetic nanoparticles

DOEpatents

Huber, Dale L [Albuquerque, NM

2011-07-05

A method for controlling the size of chemically synthesized magnetic nanoparticles that employs magnetic interaction between particles to control particle size and does not rely on conventional kinetic control of the reaction to control particle size. The particles are caused to reversibly agglomerate and precipitate from solution; the size at which this occurs can be well controlled to provide a very narrow particle size distribution. The size of particles is controllable by the size of the surfactant employed in the process; controlling the size of the surfactant allows magnetic control of the agglomeration and precipitation processes. Agglomeration is used to effectively stop particle growth to provide a very narrow range of particle sizes.

Alternative materials for the modification and stabilization of unstable subgrade soils

DOT National Transportation Integrated Search

1997-05-01

This study examines two lime by-products and two fly ashes for treatment of unstable (CBR<6) subgrade soils. The treatment methods include both modification and stabilization. Modification is temporily enhancing subgrade stability to improve construc...

Agglomeration of nano- and microplastic particles in seawater by autochthonous and de novo-produced sources of exopolymeric substances.

PubMed

Summers, Stephen; Henry, Theodore; Gutierrez, Tony

2018-05-01

Microplastics (<5 mm) have often been studied under in-vitro conditions where plastics have been investigated in isolation. However, in the natural environment microplastics readily form agglomerates conferring the particles with properties different to their pristine counterparts. Here, we examined the interaction of exopolymers with polystyrene nanoplastics and microplastics. Formation of plastic agglomerates was examined using simulated sea surface conditions. Flow cytometry coupled with microscopy revealed that nano- and microplastic particle spheres form agglomerates in seawater with a mucilagenous material and an associated microbial community. To characterise this material, differential staining methods revealed it to be glycoprotein in composition. Exposing increasing concentrations of a marine bacterial glycoprotein EPS to nano- or microplastics revealed that these types of polymers contribute to the formation and abundance of plastic agglomerates. This work highlights the importance of EPS on the fate of plastic and future research should take this into account when evaluating the impact of plastics. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

Agglomeration of dust in convective clouds initialized by nuclear bursts

NASA Astrophysics Data System (ADS)

Bacon, D. P.; Sarma, R. A.

Convective clouds initialized by nuclear bursts are modeled using a two-dimensional axisymmetric cloud model. Dust transport through the atmosphere is studied using five different sizes ranging from 1 to 10,000 μm in diameter. Dust is transported in the model domain by advection and sedimentation. Water is allowed to condense onto dust particles in regions of supersaturation in the cloud. The agglomeration of dust particles resulting from the collision of different size dust particles is modeled. The evolution of the dust mass spectrum due to agglomeration is modeled using a numerical scheme which is mass conserving and has low implicit diffusion. Agglomeration moves mass from the small particles with very small fall velocity to the larger sizes which fall to the ground more readily. Results indicate that the dust fallout can be increased significantly due to this process. In preliminary runs using stable and unstable environmental soundings, at 30 min after detonation the total dust in the domain was 11 and 30%, respectively, less than a control case without agglomeration.

Nanoparticle agglomerates of fluticasone propionate in combination with albuterol sulfate as dry powder aerosols

PubMed Central

El-Gendy, Nashwa; Pornputtapitak, Warangkana; Berkland, Cory

2015-01-01

Particle engineering strategies remain at the forefront of aerosol research for localized treatment of lung diseases and represent an alternative for systemic drug therapy. With the hastily growing popularity and complexity of inhalation therapy, there is a rising demand for tailor-made inhalable drug particles capable of affording the most proficient delivery to the lungs and the most advantageous therapeutic outcomes. To address this formulation demand, nanoparticle agglomeration was used to develop aerosols of the asthma therapeutics, fluticasone or albuterol. In addition, a combination aerosol was formed by drying agglomerates of fluticasone nanoparticles in the presence of albuterol in solution. Powders of the single drug nanoparticle agglomerates or of the combined therapeutics possessed desirable aerodynamic properties for inhalation. Powders were efficiently aerosolized (~75% deposition determined by cascade impaction) with high fine particle fraction and rapid dissolution. Nanoparticle agglomeration offers a unique approach to obtain high performance aerosols from combinations of asthma therapeutics. PMID:21964203

Predicting the Agglomeration of Cohesive Particles in a Gas-Solid Flow and its Effect on the Solids Flow

NASA Astrophysics Data System (ADS)

Kellogg, Kevin; Liu, Peiyuan; Lamarche, Casey; Hrenya, Christine

2017-11-01

In flows of cohesive particles, agglomerates will readily form and break. These agglomerates are expected to complicate how particles interact with the surrounding fluid in multiphase flows, and consequently how the solids flow. In this work, a dilute flow of particles driven by gas against gravity is studied. A continuum framework, composed of a population balance to predict the formation of agglomerates, and kinetic-theory-based balances, is used to predict the flow of particles. The closures utilized for the birth and death rates due to aggregation and breakage in the population balance take into account how the impact velocity (the granular temperature) affects the outcome of a collision as aggregation, rebound, or breakage. The agglomerate size distribution and solids velocity predicted by the continuum framework are compared to discrete element method (DEM) simulations, as well to experimental results of particles being entrained from the riser of a fluidized bed. Dow Corning Corporation.

Investigation of a 2-step agglomeration process performed in a rotary processor using polyethylene glycol solutions as the primary binder liquid.

PubMed

Kristensen, Jakob

2006-10-27

The purpose of this research was to investigate the use of polyethylene glycol (PEG) solutions as the primary binder liquid in a 2-step agglomeration process performed in a rotary processor and characterize the resulting granules and their tableting characteristics. This was done by granulation of binary mixtures of microcrystalline cellulose (MCC) and either lactose, calcium phosphate, acetaminophen, or theophylline, in a 1:3 ratio, using a 50% (wt/wt) aqueous solution of PEG and water as the binder liquid. Formulations containing lactose were agglomerated using 5 different amounts of the PEG binder solution, giving rise to a PEG content in the range of 6% to 43% (wt/wt). The process outcome was characterized according to adhesion, yield, and water requirement, and the prepared granules were characterized according to size, size distribution, and flow properties as well as tableting properties. The agglomeration of all mixtures resulted in high yields of free-flowing agglomerates and gave rise to good reproducibility of the investigated agglomerate characteristics. The process allowed for the incorporation of 42.5% (wt/wt) PEG, which is higher than the percentage of PEG reported for other equipment. Tablets of sufficient strength could be prepared with all investigated excipients using 20% wt/wt PEG; higher PEG contents gave rise to adhesion and prolonged disintegration. In conclusion, agglomeration in a torque-controlled rotary processor using solutions of PEG as the primary binder liquid was found to be a robust process, suitable for the incorporation of high contents of PEG and/or drug compounds.

The Physics of Protoplanetesimal Dust Agglomerates. VIII. Microgravity Collisions between Porous SiO{sub 2} Aggregates and Loosely Bound Agglomerates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whizin, Akbar D.; Colwell, Joshua E.; Blum, Jürgen, E-mail: Akbar.Whizin@ucf.edu

2017-02-10

We performed laboratory experiments colliding 0.8–1.0 mm and 1.0–1.6 mm SiO{sub 2} dust aggregates with loosely bound centimeter-sized agglomerates of those aggregates in microgravity. This work builds on previous microgravity laboratory experiments examining the collisional properties of porous loosely bound dust aggregates. In centimeter-sized aggregates, surface forces dominate self-gravity and may play a large role in aggregate growth beyond this size range. We characterize the properties of protoplanetary aggregate analogs to help place constraints on initial formation mechanisms and environments. We determined several important physical characteristics of these aggregates in a large number of low-velocity collisions. We observed low coefficientsmore » of restitution and fragmentation thresholds near 1 m s{sup −1} for 1–2 cm agglomerates, which are in good agreement with previous findings in the literature. We find the accretion efficiency for agglomerates of loosely bound aggregates to be higher than that for just aggregates themselves. We find sticking thresholds of 6.6 ± 2 cm s{sup −1}, somewhat higher than those in similar studies, which have observed few aggregates stick at speeds of under 3 cm s{sup −1}. Even with highly dissipative collisions, loosely bound agglomerates have difficulty accreting beyond centimeter-sized bodies at typical collision speeds in the disk. Our results indicate agglomerates of porous aggregates have slightly higher sticking thresholds than previously thought, allowing possible growth to decimeter-sized bodies if velocities are low enough.« less

Novel Binders and Methods for Agglomeration of Ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. K. Kawatra; T. C. Eisele; K. A. Lewandowski

2006-12-31

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that willmore » work satisfactorily. Primary examples of this are copper heap leaching, where there are no binders that will work in the acidic environment encountered in this process, and advanced ironmaking processes, where binders must function satisfactorily over an extraordinarily large range of temperatures (from room temperature up to over 1200 C). As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching and advanced primary ironmaking. This project has identified several acid-resistant binders and agglomeration procedures that can be used for improving the energy efficiency of heap leaching, by preventing the ''ponding'' and ''channeling'' effects that currently cause reduced recovery and extended leaching cycle times. Methods have also been developed for iron ore processing which are intended to improve the performance of pellet binders, and have directly saved energy by increasing filtration rates of the pelletization feed by as much as 23%.« less

Optical Absorbance Enhancement in PbS QD/Cinnamate Ligand Complexes.

PubMed

Kroupa, Daniel M; Vörös, Márton; Brawand, Nicholas P; Bronstein, Noah; McNichols, Brett W; Castaneda, Chloe V; Nozik, Arthur J; Sellinger, Alan; Galli, Giulia; Beard, Matthew C

2018-06-08

We studied the optical absorption enhancement in colloidal suspensions of PbS quantum dots (QD) upon ligand exchange from oleate to a series of cinnamate ligands. By combining experiments and ab initio simulations, we elucidate physical parameters that govern the optical absorption enhancement. We find that, within the cinnamate/PbS QD system, the optical absorption enhancement scales linearly with the electronic gap of the ligand, indicating that the ligand/QD coupling occurs equally efficient between the QD and ligand HOMO and their respective LUMO levels. Disruption of the conjugation that connects the aromatic ring and its substituents to the QD core causes a reduction of the electronic coupling. Our results further support the notion that the ligand/QD complex should be considered as a distinct chemical system with emergent behavior rather than a QD core with ligands whose sole purpose is to passivate surface dangling bonds and prevent agglomeration.

Enhanced damage resistance and novel defect structure of CrFeCoNi under in situ electron irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, Mo -Rigen; Wang, Shuai; Jin, Ke

Defect production and growth in CrFeCoNi, a single-phase concentrated solid solution alloy, is characterized using in situ electron irradiation inside a transmission electron microscope operated at 400–1250 kV and 400 °C. All observed defects are interstitial-type, either elliptical Frank loops or polygonal (mostly rhombus) perfect loops. Both forms of loops in CrFeCoNi exhibit a sublinear power law of growth that is > 40 times slower than the linear defect growth in pure Ni. Lastly, this result shows how compositional complexity impacts the production of Frenkel pairs and the agglomeration of interstitials into loops, and, thus, enhances the radiation tolerance.

Monodispersed ZIF-8 particles with enhanced performance for CO2 adsorption and heterogeneous catalysis

NASA Astrophysics Data System (ADS)

Guan, Yebin; Shi, Juanjuan; Xia, Ming; Zhang, Jun; Pang, Zhenfeng; Marchetti, Alessandro; Wang, Xiaohong; Cai, Jingsong; Kong, Xueqian

2017-11-01

Monodispersed zeolitic imidazolate frameworks (ZIFs) were prepared with a simple method using dimethylsulfoxide (DMSO) as solvent. This method yields ZIF-8 nanoparticles with a narrow particle size distribution of 90-110 nm and the dispersion is highly stable against agglomeration. These particles have larger nanosized porosity and enhanced CO2 adsorption capability compared to ZIF-8 prepared with different solvents such as methanol or N, N-dimethyl formamide. Their uniform size and surface chemistry also lead to superior performance in the Knoevenagel condensation reactions. The ZIF-8 nanoparticles possess high thermal stability up to 550 °C and the preparation steps are easy for scaling up which are favorable for industrial applications.

Enhanced damage resistance and novel defect structure of CrFeCoNi under in situ electron irradiation

DOE PAGES

He, Mo -Rigen; Wang, Shuai; Jin, Ke; ...

2016-07-25

Defect production and growth in CrFeCoNi, a single-phase concentrated solid solution alloy, is characterized using in situ electron irradiation inside a transmission electron microscope operated at 400–1250 kV and 400 °C. All observed defects are interstitial-type, either elliptical Frank loops or polygonal (mostly rhombus) perfect loops. Both forms of loops in CrFeCoNi exhibit a sublinear power law of growth that is > 40 times slower than the linear defect growth in pure Ni. Lastly, this result shows how compositional complexity impacts the production of Frenkel pairs and the agglomeration of interstitials into loops, and, thus, enhances the radiation tolerance.

Mechanism of magnetoresistance ratio enhancement in MgO/NiFe/MgO heterostructure by rapid thermal annealing

NASA Astrophysics Data System (ADS)

Zhao, Chong-Jun; Liu, Yang; Zhang, Jing-Yan; Sun, Li; Ding, Lei; Zhang, Peng; Wang, Bao-Yi; Cao, Xing-Zhong; Yu, Guang-Hua

2012-08-01

To reveal thermal effects on the film quality/microstructure evolution and the resulted magnetoresistance (MR) ratio in MgO/NiFe/MgO heterostructures, positron annihilation spectroscopy studies have been performed. It is found that the ionic interstitials in the MgO layers recombine with the nearby vacancies at lower annealing temperatures (200-300 °C) and lead to a slow increase in sample MR. Meanwhile, vacancy defects agglomeration/removal and ordering acceleration in MgO will occur at higher annealing temperatures (450-550 °C) and the improved MgO and MgO/NiFe interfaces microstructure are responsible for the observed significant MR enhancement.

Ethanol at levels produced by Saccharomyces cerevisiae during wheat dough fermentation has a strong impact on dough properties.

PubMed

Jayaram, Vinay B; Rezaei, Mohammad N; Cuyvers, Sven; Verstrepen, Kevin J; Delcour, Jan A; Courtin, Christophe M

2014-09-24

Yeast's role in bread making is primarily the fermentative production of carbon dioxide to leaven the dough. Fermentation also impacts dough matrix rheology, thereby affecting the quality of the end product. Surprisingly, the role of ethanol, the other yeast primary metabolite, has been ill studied in this context. Therefore, this study aims to assess the potential impact of ethanol on yeastless dough extensibility and spread and gluten agglomeration at concentrations at which it is produced in fermenting dough, i.e., up to 60 mmol per 100 g of flour. Reduced dough extensibility and dough spread were observed upon incorporation of ethanol in the dough formula, and were more pronounced for a weak than for a strong flour. Uniaxial and biaxial extension tests showed up to 50% decrease in dough extensibility and a dough strength increase of up to 18% for 60 mmol of ethanol/100 g of flour. Ethanol enhanced gluten agglomeration of a weak flour. Sequential extraction of flour in increasing ethanol concentrations showed that better gluten-solvent interaction is a possible explanation for the changed dough behavior.

Agglomeration Multigrid for an Unstructured-Grid Flow Solver

NASA Technical Reports Server (NTRS)

Frink, Neal; Pandya, Mohagna J.

2004-01-01

An agglomeration multigrid scheme has been implemented into the sequential version of the NASA code USM3Dns, tetrahedral cell-centered finite volume Euler/Navier-Stokes flow solver. Efficiency and robustness of the multigrid-enhanced flow solver have been assessed for three configurations assuming an inviscid flow and one configuration assuming a viscous fully turbulent flow. The inviscid studies include a transonic flow over the ONERA M6 wing and a generic business jet with flow-through nacelles and a low subsonic flow over a high-lift trapezoidal wing. The viscous case includes a fully turbulent flow over the RAE 2822 rectangular wing. The multigrid solutions converged with 12%-33% of the Central Processing Unit (CPU) time required by the solutions obtained without multigrid. For all of the inviscid cases, multigrid in conjunction with an explicit time-stepping scheme performed the best with regard to the run time memory and CPU time requirements. However, for the viscous case multigrid had to be used with an implicit backward Euler time-stepping scheme that increased the run time memory requirement by 22% as compared to the run made without multigrid.

Method for directly recovering fluorine from gas streams

DOEpatents

Orlett, Michael J.; Saraceno, Anthony J.

1981-01-01

This invention is a process for the direct recovery of gaseous fluorine from waste-gas streams or the like. The process comprises passing the gas stream through a bed of anhydrous K.sub.3 NiF.sub.6 pellets to fluorinate the same to K.sub.3 NiF.sub.7 and subsequently desorbing the fluorine by heating the K.sub.3 NiF.sub.7 pellets to a temperature re-converting them to K.sub.3 NiF.sub.6. The efficiency of the fluorine-absorption step is maximized by operating in a selected and conveniently low temperature. The desorbed fluorine is highly pure and is at a pressure of several atmospheres. Preferably, the K.sub.3 NiF.sub.6 pellets are prepared by a method including the steps of forming agglomerates of hydrated K.sub.3 NiF.sub.5, sintering the agglomerates to form K.sub.3 NiF.sub.5 pellets of enhanced reactivity with respect to fluorine, and fluorinating the sintered pellets to K.sub.3 NiF.sub.6.

The ash in forest fire affected soils control the soil losses. Part 1. The pioneer research

NASA Astrophysics Data System (ADS)

Cerdà, Artemi; Pereira, Paulo

2013-04-01

After forest fires, the ash and the remaining vegetation cover on the soil surface are the main protection against erosion agents. The control ash exert on runoff generation mechanism was researched during the 90's (Cerdà, 1998a; 1998b). This pioneer research demonstrated that after forest fires there is a short period of time that runoff and surface wash by water is controlled by the high infiltration rates achieved by the soil, which were high due to the effect of ash acting as a mulch. The research of Cerdà (1998a; 1998b) also contributed to demonstrate that runoff was enhanced four month later upon the wash of the ash by the runoff, but also due to the removal of ash due to dissolution and water infiltration. As a consequence of the ephemeral ash cover the runoff and erosion reached the peak after the removal of the ash (usually four month), and for two years the soil erosion reached the peak (Cerdà, 1998a). Research developed during the last decade shown that the ash and the litter cover together contribute to reduce the soil losses after the forest fire (Cerdà and Doerr, 2008). The fate of the ash is related to the climatic conditions of the post-fire season, as intense thunderstorms erode the ash layer and low intensity rainfall contribute to a higher infiltration rate and the recovery of the vegetation. Another, key factor found during the last two decades that determine the fate of the ash and the soil and water losses is the impact of the fauna (Cerdà and Doerr, 2010). During the last decade new techniques were developed to study the impact of ash in the soil system, such as the one to monitor the ash changes by means of high spatial resolution photography (Pérez Cabello et al., 2012), and laboratory approaches that show the impact of ash as a key factor in the soil hydrology throughout the control they exert on the soil water repellency (Bodí et al., 2012). Laboratory approaches also shown that the fire severity is a key factor on the ash chemical composition (Pereira and Úbeda, 2010) and Pereira et al., 2012). Some of the new research challenges related to ash impact in the fire affected soils are related to the ash redistribution after the fire, the impact of ash in soil and water chemistry, the temporal changes of soil erosion, the control ash exert on vegetation recovery and the role to be played by ash in the best management of fire affected land. Those topics needs new ideas and new scientists such as Paulo Pereira show in the Part II of this abstract. Acknowledgements, Lithuanian Research Council. Project LITFIRE, Fire effects on Lithuanian soils and ecosystems (MIP-48/2011) and the research projects GL2008-02879/BTE and LEDDRA 243857. References Bodí, M., Mataix-Solera, J., Doerr, S., and Cerdà, A. 2011b. The wettability of ash from burned vegetation and its relationship to Mediterranean plant species type, burn severity and total organic carbon content. Geoderma, 160, 599-607. Cerdà, A. 1998a. Postfire dynamics of erosional processes under mediterranean climatic conditions. Z. Geomorphol., 42 (3) 373-398. Cerdà, A. 1998b. Changes in overland flow and infiltration after a rangeland fire in a Mediterranean scrubland. Hydrological Processes, 12, 1031-1042. Cerdà, A., and Doerr, S. H.2010. The effect of ant mounds on overland flow and soil erodibility following a wildfire in eastern Spain. Ecohydrology, 3, 392-401. Cerdà, A., and Doerr, S.H. 2008. The effect of ash and needle cover on surface runoff and erosion in the immediate post-fire period. Catena, 74, 256-263. Pereira, P., and Úbeda, X. 2010. Spatial distribution of heavy metals released from ashes after a wildfire, Journal of Environment Engineering and Landscape Management, 18, 13-22. Pereira, P., Ubeda, X., Martin, D.A. 2012. Fire severity effects on ash chemical composition and extractable elements. Geoderma, 191, 105 - 114. Pérez-Cabello, F., Cerdà, A., de la Riva, J., Echeverría, M.T., García-Martín, A., Ibarra, P., Lasanta, T., Montorio, R., Palacios, V. 2012. Micro-scale post-fire surface cover changes monitored using high spatial resolution photography in a semiarid environment: A useful tool in the study of post-fire soil erosion processes. Journal of Arid Environments, 76, 88-96.

SEVIRI 4D-var assimilation analysing the April 2010 Eyjafjallajökull ash dispersion

NASA Astrophysics Data System (ADS)

Lange, Anne Caroline; Elbern, Hendrik

2016-04-01

We present first results of four dimensional variational (4D-var) data assimilation analysis applying SEVIRI observations to the Eulerian regional chemistry and aerosol transport model EURAD-IM (European Air Pollution Dispersion - Inverse Model). Optimising atmospheric dispersion models in terms of volcanic ash transport predictions by observations is especially essential for the aviation industry and associated interests. Remote sensing satellite observations are instrumental for ash detection and monitoring. We choose volcanic ash column retrievals of the Spinning Enhanced Visible and Infrared Imager (SEVIRI) because as infrared instrument on the geostationary satellite Meteosat Second Generation it delivers measurements with high temporal resolution during day and night. The retrieval method relies on the reverse absorption effect. In the framework of the national initiative ESKP (Earth System Knowledge Platform) and the European ACTRIS-2 (Aerosol, Clouds, and Trace gases Research InfraStructure) project, we developed new modules (forward and adjoint) within the EURAD-IM, which are able to process SEVIRI ash column data as observational input to the 4D-var system. The focus of the 4D-var analysis is on initial value optimisation of the volcanic ash clouds that were emitted during the explosive Eyjafjallajökull eruption in April 2010. This eruption caused high public interest because of air traffic closures and it was particularly well observed from many different observation systems all over Europe. Considering multiple observation periods simultaneously in one assimilation window generates a continuous trajectory in the phase space and ensures that past observations are considered within their uncertainties. Results are validated mainly by lidar (LIght Detection And Ranging) observations, both ground and satellite based.

Near Real Time Detection and Tracking of the EYJAFJÖLL (iceland) Ash Cloud by the RST (robust Satellite Technique) Approach

NASA Astrophysics Data System (ADS)

Tramutoli, V.; Filizzola, C.; Marchese, F.; Paciello, R.; Pergola, N.; Sannazzaro, F.

2010-12-01

Volcanic ash clouds, besides to be an environmental issue, represent a serious problem for air traffic and an important economic threat for aviation companies. During the recent volcanic crisis due to the April-May 2010 eruption of Eyjafjöll (Iceland), ash clouds became a real problem for common citizens as well: during the first days of the eruption thousands of flights were cancelled disrupting hundred of thousands of passengers. Satellite remote sensing confirmed to be a crucial tool for monitoring this kind of events, spreading for thousands of kilometres with a very rapid space-time dynamics. Especially weather satellites, thanks to their high temporal resolution, may furnish a fundamental contribution, providing frequently updated information. However, in this particular case ash cloud was accompanied by a sudden and significant emission of water vapour, due to the ice melting of Eyjafjallajökull glacier, making satellite ash detection and discrimination very hard, especially in the first few days of the eruption, exactly when accurate information were mostly required in order to support emergency management. Among the satellite-based techniques for near real-time detection and tracking of ash clouds, the RST (Robust Satellite Technique) approach, formerly named RAT - Robust AVHRR Technique, has been long since proposed, demonstrating high performances both in terms of reliability and sensitivity. In this paper, results achieved by using RST-based detection schemes, applied during the Eyjafjöll eruption were presented. MSG-SEVIRI (Meteosat Second Generation - Spinning Enhanced and Visible Infrared Imager) records, with a temporal sampling of 15 minutes, were used applying a standard as well as an advanced RST configuration, which includes the use of SO2 absorption band together with TIR and MIR channels. Main outcomes, limits and possible future improvements were also discussed.

Properties of volcanic soils in cold climate conditions

NASA Astrophysics Data System (ADS)

Kuznetsova, Elena

2017-04-01

Layers of volcanic ash and the Andosol soils derived from them may play an important role in preserving snow and ice as well as developing permafrost conditions in the immediate vicinity of volcanoes of high elevation or those situated at high latitudes, and land areas, often distant from volcanic activity that are either prone to permafrost or covered by snow and ice, but are affected by the deposition of subaerial ash. The special properties of volcanic ash that are responsible are critically reviewed particularly in relation to recent research in Kamchatka in the Far East of Russia. Of particular importance are the thermal properties and the unfrozen water contents of ash layers and the rate at which the weathering of volcanic glass takes place. Volcanic glass is the most easily weathered component of volcanic ejecta (Shoji et al., 1993; Kimble et al., 2000). There are many specific environmental conditions, including paleoclimate and present-day climate, the composition of volcanic tephra and glaciation history, which cause the differences in weathering and development of volcanic ash soils (Zehetner et al., 2003). The preservation of in situ, unweathered, and unaltered surficial ash-fall deposits in the cold regions has important implications for paleoclimate and glacial history. Ash-fall deposits, which trap and preserve the soils, sediments, and landforms on which they fall, can be used to resolve local climate conditions (temperature and moisture) at the ash site during ash-fall deposition. The preservation of detailed sedimentary features (e.g. bedding in the ash, sharpness of stratigraphic contacts) can tell us about their post-depositional history, whether they have been redeposited by wind or water, or overridden by glaciers (Marchant et al., 1996). Weathering of volcanic glass results in the development of amorphous clay minerals (e.g. allophane, opal, palagonite) but this takes place much slower in cold than under warmer climate conditions. Only few studies on weathering of volcanic ash and developing volcanic soils under cold climatic conditions were carried out, especially in areas with permafrost (Bäumler, 2003). Most of research on volcanic permafrost soils was done in Yukon (Canada), Kamchatka (Russia), and Antarctica, or on seasonal frost in mountain area in Iceland, Japan, New Zealand, and Ecuador. Soils of Iceland and Antarctica are used as terrestrial analogs to Martian soils (Gooding & Keil, 1978; Allen et al., 1981). The review of existing data demonstrates that there is a strong correlation between the thermal conductivity, the water-ice content, and the mineralogy of the weathered part of the volcanic ash, enhanced amount of amorphous clay minerals (allophane, palagonite) increase the proportion of unfrozen water and decrease thermal conductivity (Kuznetsova et al., 2012, 2013; Kuznetsova & Motenko, 2014), and amorphous silica does not alter to halloysite or other clay minerals even in ashes of Early Pleistocene age (Kamchatka) or Miocene and Pliocene deposits (Antarctica) due to cold temperatures. The significance of these findings is discussed in relation to the reconstruction of past climates and the influence of volcanic ash on permafrost aggradation and degradation, snow and ice ablation, and the development of glaciers.

Assessment of compost application to coal ash disposal sites to promote the rapid vegetation establishment

NASA Astrophysics Data System (ADS)

Repmann, F.; Slazak, A.; Babic, M.; Schneider, B. U.; Schaaf, W.; Hüttl, R. F.

2009-04-01

In the city of Tuzla, located in Bosnia and Herzegovina, a coal fired thermo electric power plant is operated by the company JP ELEKTROPRIVERDA BIH TERMOELEKTRANA "TUZLA". High amounts of ash are produced by the power plant, which are currently disposed into settlement ponds bordered by dams in natural valleys. A total of four ash disposal sites covering an area of approx. 170 ha have been established during the last decades. Due to the fact that residual ash from coal combustion was found to contain a variety of trace elements (Ni, Cr, As, B), it must be assumed that ash disposal of that magnitude constitutes an environmental problem which is investigated within the EU-FP6 / STREP project "Reintegration of Coal Ash Disposal Sites and Mitigation of Pollution in the West Balkan Area" RECOAL. The main hazards relate to soil and groundwater contamination due to leaching toxins, dust dispersion, and toxins entering the food chain as these disposal sites are used for agricultural purposes. In order to rapidly establish a vegetation cover on barren ash dumps that particularly would prevent dust erosion we assessed the applicability of compost, produced from locally available municipal and industrial organic residues as an amendment to ash to improve substrate fertility. The envisaged remediation technology was considered to be a low cost, easy applicable and rapid method capable of substantially enhancing living conditions of residents in the vicinity of the abandoned disposal sites. Various compost application rates were evaluated in the field on experimental site Divkovici I in Tuzla and additionally in the greenhouse environment at Brandenburg Technical University Cottbus. Field and laboratory tests revealed that plant growth and cover rate can substantially be improved by mixing compost into the upper ash layer to a maximum depth of approx. 20 cm. Besides direct growth observations in the field analysis of soil parameters gave evidence that the fertility of ashy substrates amended with compost produced from locally available sewage sludge and saw dust can be improved. The metal content of grass grown in the various treatments was considered to be elevated compared to normal contents. However, metal uptake in compost treatments was lower than in untreated plots. A preliminary cost assessment, comparing the remediation technology tested on site Divkovici with a standard soil covering technique revealed financial benefits for the compost method due to significant lower application rates.

Removal of boron from ceramic industry wastewater by adsorption-flocculation mechanism using palm oil mill boiler (POMB) bottom ash and polymer.

PubMed

Chong, Mei Fong; Lee, Kah Peng; Chieng, Hui Jiun; Syazwani Binti Ramli, Ili Izyan

2009-07-01

Boron is extensively used in the ceramic industry for enhancing mechanical strength of the tiles. The discharge of boron containing wastewater to the environment causes severe pollution problems. Boron is also dangerous for human consumption and causes organisms' reproductive impediments if the safe intake level is exceeded. Current methods to remove boron include ion-exchange, membrane filtration, precipitation-coagulation, biological and chemical treatment. These methods are costly to remove boron from the wastewater and hence infeasible for industrial wastewater treatment. In the present research, adsorption-flocculation mechanism is proposed for boron removal from ceramic wastewater by using Palm Oil Mill Boiler (POMB) bottom ash and long chain polymer or flocculant. Ceramic wastewater is turbid and milky in color which contains 15 mg/L of boron and 2000 mg/L of suspended solids. The optimum operating conditions for boron adsorption on POMB bottom ash and flocculation using polymer were investigated in the present research. Adsorption isotherm of boron on bottom ash was also investigated to evaluate the adsorption capacity. Adsorption isotherm modeling was conducted based on Langmuir and Freundlich isotherms. The results show that coarse POMB bottom ash with particle size larger than 2 mm is a suitable adsorbent where boron is removed up to 80% under the optimum conditions (pH=8.0, dosage=40 g bottom ash/300 ml wastewater, residence time=1h). The results also show that KP 1200 B cationic polymer is effective in flocculating the suspended solids while AP 120 C anionic polymer is effective in flocculating the bottom ash. The combined cationic and anionic polymers are able to clarify the ceramic wastewater under the optimum conditions (dosage of KP 1200 B cationic polymer=100 mg/L, dosage of AP 120 C anionic polymer=50 mg/L, mixing speed=200 rpm). Under the optimum operating conditions, the boron and suspended solids concentration of the treated wastewater were reduced to 3 mg/L and 5 mg/L respectively, satisfying the discharge requirement by Malaysia Department of Environment (DOE). The modeling study shows that the adsorption isotherm of boron onto POMB bottom ash conformed to the Freundlich Isotherm. The proposed method is suitable for boron removal in ceramic wastewater especially in regions where POMB bottom ash is abundant.

Recent Advances in Agglomerated Multigrid

NASA Technical Reports Server (NTRS)

Nishikawa, Hiroaki; Diskin, Boris; Thomas, James L.; Hammond, Dana P.

2013-01-01

We report recent advancements of the agglomerated multigrid methodology for complex flow simulations on fully unstructured grids. An agglomerated multigrid solver is applied to a wide range of test problems from simple two-dimensional geometries to realistic three- dimensional configurations. The solver is evaluated against a single-grid solver and, in some cases, against a structured-grid multigrid solver. Grid and solver issues are identified and overcome, leading to significant improvements over single-grid solvers.

Effect of composition on physical properties of food powders

NASA Astrophysics Data System (ADS)

Szulc, Karolina; Lenart, Andrzej

2016-04-01

The paper presents an influence of raw material composition and technological process applied on selected physical properties of food powders. Powdered multi-component nutrients were subjected to the process of mixing, agglomeration, coating, and drying. Wetting liquids ie water and a 15% water lactose solution, were used in agglomeration and coating. The analyzed food powders were characterized by differentiated physical properties, including especially: particle size, bulk density, wettability, and dispersibility. The raw material composition of the studied nutrients exerted a statistically significant influence on their physical properties. Agglomeration as well as coating of food powders caused a significant increase in particle size, decreased bulk density, increased apparent density and porosity, and deterioration in flowability in comparison with non-agglomerated nutrients.

Study on spatial-temporal change of Changsha-Zhuzhou-Xiangtan urban agglomeration based on DMSP / OLS night light data

NASA Astrophysics Data System (ADS)

Li, Mao; Li, Lel-in

2018-03-01

For the sake of curbing the spreading of Changsha-Zhuzhou-Xiangtan urban agglomeration and spatial disorder in the process of urbanization development on the regional bearing capacity of land resources and ecological environment and assisting to plan the integration process of ChangZhuTan,this paper uses the DMSP/OLS night light data of Chang ZhuTan in 1992 to 2013 to invert the urbanization process index of ChangZhuTan urban agglomeration. Based on the two scales of time and space, this paper analyzes the average index of lights, the speed of urban expansion and urban compactness index et al and studies the temporal and spatial characteristics of ChangZhuTan urban agglomeration in this period.

Development of the fine-particle agglomerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feldman, P.; Balasic, P.

1999-07-01

This paper presents the current status of the commercial development of a new technology to more efficiently control fine particulate emissions. The technology is based on an invention by Environmental Elements Corporation (EEC) which utilizes laminar flow to promote contact of fine submicron particles with larger particles to form agglomerates prior to their removal in a conventional particulate control device, such as an ESP. As agglomerates the particles are easily captured in the control device, whereas a substantial amount would pass through if allowed to remain as fine particles. EEC has developed the laminar-flow agglomerator technology through the laboratory proof-of-conceptmore » stage, which was funded by a DOE SBIR grant, to pilot-scale and full-scale demonstrations.« less

Residual oil fly ash induces cytotoxicity and mucin secretion by guinea pig tracheal epithelial cells via an oxidant-mediated mechanism.

PubMed

Jiang, N; Dreher, K L; Dye, J A; Li, Y; Richards, J H; Martin, L D; Adler, K B

2000-03-15

Inhalation of ambient air particulate matter (PM) is associated with pulmonary injury and inflammation. Using primary cultures of guinea pig tracheal epithelial (GPTE) cells as an in vitro model of airway epithelium, we examined effects of exposure to suspensions of six different emission and ambient air PM samples: residual oil fly ash (ROFA) from an electrical power plant; fly ash from a domestic oil burning furnace (DOFA); ambient air dust from St. Louis (STL), Ottawa (OT), and Washington, DC (WDC); and volcanic ash from the eruption of Mount Saint Helens (MSH) in 1980. Effects of these particulates on cell viability (assessed via LDH assay), secretion of mucin (measured by a monoclonal antibody-based ELISA), and steady-state mRNA levels of the mucin gene MUC2 were determined. ROFA was the most toxic of the dusts tested, as it significantly increased LDH release following a 24-h incubation with 50 microg/cm(2) ROFA. ROFA also enhanced MUC2 mRNA after 4-h exposure, and mucin secretion after 8 h. ROFA-induced mucin secretion and cytotoxicity were attenuated by the oxidant scavenger, dimethylthiourea (DMTU). ROFA exposure also depleted cells of glutathione (GSH). Relatedly, depletion of intracellular GSH by treatment of the cells with buthionine sulfoxamine (BSO) also provoked mucin secretion, as well as enhancing the secretory effect of ROFA when the two agents were added together. L-NMA, the nitric oxide synthase (NOS) inhibitor, did not affect ROFA-induced mucin secretion. Of the soluble transition metals in ROFA (nickel, iron, vanadium), only vanadium individually, or combinations of the metals containing vanadium, provoked secretion. The results suggest ROFA enhances mucin secretion and generates toxicity in vitro to airway epithelium via a mechanism(s) involving generation of oxidant stress, perhaps related to depletion of cellular antioxidant capacity. Deleterious effects of inhalation of ROFA in the respiratory tract in vivo may relate to these cellular responses. Vanadium, a component of ROFA, may be important in generating these reactions. Copyright 2000 Academic Press.

Advancing the Renewable Industry in Minnesota

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sparby, Michael; Doering, Alan; Timmerman, Denny

This report deals with seven topics: 1. "Utilizing Ash Wastes as a Nutrient Source for Corn": As forms of gasification and combustion grow in the area of renewable energy in Minnesota the question arises regarding the utilization/application of the ash co product produced from these processes. Currently there are four facilities in Minnesota producing an ash co product (three ethanol facilities and one combusting biomass to produce energy). These ash wastes are generated from using ethanol by-products as a fuel or heating source for fermentation. Other ash wastes from agricultural sources include turkey litter ash. When applied to agricultural fields,more » ash wastes can be a source of nutrients for agricultural crops. Chemical analyses of ash wastes vary, but 200 to 300 lb of P 2O 5 and K 2O per ton of ash is typical. The value of ash wastes as a fertilizer has increased because commercial fertilizer prices have increased significantly over the last few years. Specifically: Compaction/Agglomeration research- Research included development of an appropriate product for use in current delivery systems by densifying the ash into the form of pellets or briquettes which may reduce fertilizer input cost to farmers. The initiative addresses the use of phosphorus and potassium from co-firing or gasification processes as a fertilizer source. 2. "Use of Glycerol as a Corn Replacement in Calf Starter Diets": Glycerol is a sugar alcohol by-product of bio-diesel production. About 1 gallon of glycerin is produced for every 10 gallons of bio-diesel of which the glycerol content may vary between 63 and almost 100%. There is some uncertainty of the exact energy value of glycerol as an ingredient for animal feed but it has been successfully used as a replacement for corn up to 10% of the diet dry matter for lactating dairy cows. There is a lack of information on incorporating glycerol into diets for pre- and post weaned dairy heifer calves which has the potential to expand the market for this by product. Preliminary work at SROC indicates that there are no palatability problems using glycerol up to 6% of the mix in post weaning pellets for group fed dairy heifers. 3. "Intervention Strategies for Reduction of Food-borne Pathogens in Cattle Fed Ethanol Byproducts": Ethanol plants and cattle producers create a symbiotic relationship: The use of wet and dry distiller’s grains in beef cattle rations provides significant improvement in overall feedlot performance for many producers in Minnesota and the Upper Midwest. Distiller’s grain is the coproduct that remains following the distillation of ethanol. It may be dehydrated to produce dried distiller’s grain (DDG) which is then commonly used as livestock feed. The use of distiller’s grains in livestock rations has been the subject of numerous research projects over the past ten years. Recently published research data conducted at Kansas State University (K-State) has created controversy over the feeding of distiller’s grains in beef cattle rations. The research indicates that cattle fed distiller’s grain may have an increased probability of Escherichia coli O157 in their hindgut. Specifically: This research assessment was a two part project consisting of feeding trials conducted at the University of Minnesota and an intervention study conducted at Kansas State University. This report is the Kansas State University portion. This report is a task-level final technical report. 4. "Impact of Distillers' Grains and Glycerin on Cattle Fecal Shedding of Escherichia coli O157:H7" 5. "Study Assessing the Opportunities and Potential of Soybean Based Products and Technologies": Based on demand/market potential, economic feasibility, stage of development and strength of institutional support, Informa Economics, Inc. ("Informa") narrowed down a list of more than 100 emerging soybean products and to 8 of the most promising for soybean, considered to have the greatest potential to add significant value to Minnesota's soybean commodity production. However, as with the potential of any biobased product or technology, the development of these emerging soybean products and technologies will be heavily reliant on future market price environments (especially for petroleum) and government policies. This report identifies what the contractor believes are the top 8 products and technologies for soybeans at the time of publishing. 6. "Study Assessing the Opportunities and Potential of Corn-Based Products and Technologies": Based on demand/market potential, economic feasibility, stage of development and strength of institutional support, Informa Economics, Inc. ("Informa") narrowed down a list of more than 100 emerging corn products and technologies to 8 of the most promising for corn, considered to have the greatest potential to add significant value to Minnesota's corn commodity production. However, as with the potential of any biobased product or technology, the development of these emerging corn products and technologies will be heavily reliant on future market price environments (especially for petroleum) and government policies. This report identifies what the contractor believes are the top 8 products and technologies for corn at the time of publishing. 7. "Distributed Power Generation Technology (Roseau Gasification)."« less

²²⁶Ra, ²³²Th and ⁴⁰K radionuclides enhancement rate and dose assessment for residues of lignite-fired thermal power plants in Turkey.

PubMed

Parmaksiz, A; Arikan, P; Vural, M; Yeltepe, E; Tükenmez, I

2011-11-01

A total of 77 coal, slag and fly ash samples collected from six thermal power plants were measured by gamma-ray spectrometry. The average (226)Ra activity concentrations in coal, slag and fly ash were measured as 199.8±16.7, 380.3±21.8 and 431.5±29.0 Bq kg(-1), respectively. The average (232)Th activity concentrations in coal, slag and fly ash were measured as 32.0±2.4, 74.0±9.0 and 87.3±9.8 Bq kg(-1), respectively. The average (40)K activity concentrations in coal, slag and fly ash were found to be 152.8±12.1, 401.3±25.0 and 439.0±30.2 Bq kg(-1), respectively. The radium equivalent activities of samples varied from 147.6±8.5 to 1077.4±53.3 Bq kg(-1). The gamma and alpha index of one thermal power plant's fly ash were calculated to be 3.5 and 5 times higher than that of the reference values. The gamma absorbed dose rates were found to be higher than that of the average Earth's crust. The annual effective dose of residues measured in four thermal power plants were calculated higher than that of the permitted dose rate for public, i.e. 1 mSv y(-1).

Particle agglomerated 3-d nanostructures for photon absorption

NASA Astrophysics Data System (ADS)

Sivayoganathan, Mugunthan

The main objective of this thesis is to investigate the photon absorption properties of particle agglomerated 3-D structures that are synthesized through femtosecond laser ablation of solids. The size and morphology of these particle agglomerated 3-D structures, which can be tailored through adjusting laser parameters, determine the photon absorption property. A systematic theoretical and experimental study was performed to identify the effect of lasers on the size of the formed particles. The literature survey showed that the amount of supersaturation influences the growth rate as well as the nucleation rate of vapour condensed nanoparticles. Based on this theory, a mechanism was formed to explain the control of laser parameters over the size of formed particles. Further, a theoretical explanation was proposed from the experimental results for the transition of particle size distribution modals. These proposed mechanisms and explanations show the variation in particle size in the particle agglomerated 3-D nanostructures with laser parameters. The effect of laser parameters on the formed ring size was studied. Based on the previous studies, a mechanism was proposed for the formation of ring nanoclusters. The laser pulse intensity dependent ponderomotive force was the key force to define the formation of ring nanoclusters. Then the effect of laser parameters on ring size was studied. Structures fabricated on several materials such as graphite, aluminosilicate ceramic, zinc ingot, gold, and titanium were analyzed to show the influence of material properties, laser parameters, and the environmental conditions on the size of ring formed. The studies performed on the structures showed a minimum absorption of 0.75 A.U. in the bandwidth from UV to IR. The absorption spectrum is much wider compared to existing nanomaterials, such as silicon nanostructures and titanium dioxide nanostructures. To the best of the author's knowledge, it is a very competitive absorption rate when compared with the previous nanostructures used in photovoltaic conversion. Several features of nanostructures contribute to the enhancement of this light absorption. The special feature of the structure is that ease to fabricate and modify the properties by varying the laser parameters could make it competitive among other nanostructures available for solar cells.

Self-degradable Slag/Class F Fly Ash-Blend Cements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sugama, T.; Warren, J.; Butcher, T.

2011-03-01

Self-degradable slag/Class F fly ash blend pozzolana cements were formulated, assuming that they might serve well as alternative temporary fracture sealers in Enhanced Geothermal System (EGS) wells operating at temperatures of {ge} 200 C. Two candidate formulas were screened based upon material criteria including an initial setting time {ge} 60 min at 85 C, compressive strength {ge} 2000 psi for a 200 C autoclaved specimen, and the extent of self-degradation of cement heated at {ge} 200 C for it was contacted with water. The first screened dry mix formula consisted of 76.5 wt% slag-19.0 wt% Class F fly ash-3.8 wt%more » sodium silicate as alkali activator, and 0.7 wt% carboxymethyl cellulose (CMC) as the self-degradation promoting additive, and second formula comprised of 57.3 wt% slag, 38.2 wt% Class F fly ash, 3.8 wt% sodium silicate, and 0.7 wt% CMC. After mixing with water and autoclaving it at 200 C, the aluminum-substituted 1.1 nm tobermorite crystal phase was identified as hydrothermal reaction product responsible for the development of a compressive strength of 5983 psi. The 200 C-autoclaved cement made with the latter formula had the combined phases of tobermorite as its major reaction product and amorphous geopolymer as its minor one providing a compressive strength of 5271 psi. Sodium hydroxide derived from the hydrolysis of sodium silicate activator not only initiated the pozzolanic reaction of slag and fly ash, but also played an important role in generating in-situ exothermic heat that significantly contributed to promoting self-degradation of cementitious sealers. The source of this exothermic heat was the interactions between sodium hydroxide, and gaseous CO{sub 2} and CH{sub 3}COOH by-products generated from thermal decomposition of CMC at {ge} 200 C in an aqueous medium. Thus, the magnitude of this self-degradation depended on the exothermic temperature evolved in the sealer; a higher temperature led to a sever disintegration of sealer. The exothermic temperature was controlled by the extent of thermal decomposition of CMC, demonstrating that CMC decomposed at higher temperature emitted more gaseous reactants. Hence, such large emission enhanced the evolution of in-situ exothermic heat. In contrast, the excessive formation of geopolymer phase due to more incorporation of Class F fly ash into this cementitious system affected its ability to self-degrade, reflecting that there was no self-degradation. The geopolymer was formed by hydrothermal reactions between sodium hydroxide from sodium silicate and mullite in Class F fly ash. Thus, the major reason why geopolymer-based cementitiuos sealers did not degrade after heated sealers came in contact with water was their lack of free sodium hydroxide.« less

Mount St. Helens Flyover

NASA Technical Reports Server (NTRS)

2002-01-01

This Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image of Mt. St. Helens volcano in Washington State was acquired on August 8, 2000 and covers an area of 37 by 51 km. Mount Saint Helens, a volcano in the Cascade Range of southwestern Washington that had been dormant since 1857, began to show signs of renewed activity in early 1980. On 18 May 1980, it erupted with such violence that the top of the mountain was blown off, spewing a cloud of ash and gases that rose to an altitude of 19 kilometers. The blast killed about 60 people and destroyed all life in an area of some 180 square kilometers (some 70 square miles), while a much larger area was covered with ash and debris. It continues to spit forth ash and steam intermittently. As a result of the eruption, the mountain's elevation decreased from 2,950 meters to 2,549 meters. The simulated fly-over was produced by draping ASTER visible and near infrared image data over a digital topography model, created from ASTER's 3-D stereo bands. The color was computer enhanced to create a 'natural' color image, where the vegetation appears green. The topography has been exaggerated 2 times to enhance the appearance of the relief. Landsat7 aquired an image of Mt. St. Helens on August 22, 1999. Image and animation courtesy NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

Investigation of nanoparticle agglomeration on the effective thermal conductivity of a composite material

NASA Astrophysics Data System (ADS)

Webb, Anthony J.

Phase Change Materials (PCMs), like paraffin wax, can be used for passive thermal management of portable electronics if their overall bulk thermal conductivity is increased through the addition of highly conducting nanoparticles. Finite Element Analysis (FEA) is used to investigate the influence of nanoparticle agglomeration on the overall conductive thermal transport in a nanoenhanced composite by dictating the thermal conductivity of individual elements according to their local inclusion volume fraction and characteristics inside a low conducting PCM matrix. The inclusion density distribution is dictated by an agglomeration factor, and the effective thermal conductivity of each element is calculated from the nanoparticle volume fraction using a method similar to the Representative Volume Element (RVE) methodology. FEA studies are performed for 2-D and 3-D models. In the 2-D model, the grain boundary is fixed at x = 0 for simplicity. For the 3-D model, the grain boundary geometry is randomly varied. A negligible 2-D effect on thermal transport in the 2-D model is seen, so a 1-D thermal resistance network is created for comparison, and the results agree within 4%.The influence of the agglomeration factor and contact Biot number on the overall bulk thermal conductivity is determined by applying Fourier's Law on the entire simulated composite. For the 2-D and 3-D models with a contact Biot number above 1, the overall bulk thermal conductivity decreases prior to the percolation threshold being met and then increases with increasing agglomeration. Finally, a MatlabRTM based image processing tool is created to estimate the agglomeration factor based on an experimental image of a nanoparticle distribution, with a calculated approximate agglomeration value of Beta*L = 5 which results in a bulk thermal conductivity of 0.278 W/(m-K).

PM2.5, Population Exposure and Economic Effects in Urban Agglomerations of China Using Ground-Based Monitoring Data

PubMed Central

Shen, Yonglin

2017-01-01

This paper adopts the PM2.5 concentration data obtained from 1497 station-based monitoring sites, population and gross domestic product (GDP) census data, revealing population exposure and economic effects of PM2.5 in four typical urban agglomerations of China, i.e., Beijing-Tianjin-Hebei (BTH), the Yangtze River delta (YRD), the Pearl River delta (PRD), and Chengdu-Chongqing (CC). The Cokriging interpolation method was used to estimate the PM2.5 concentration from station-level to grid-level. Next, an evaluation was conducted mainly at the grid-level with a cell size of 1 × 1 km, assisted by the urban agglomeration scale. Criteria including the population-weighted mean, the cumulative percent distribution and the correlation coefficient were applied in our evaluation. The results showed that the spatial pattern of population exposure in BTH was consistent with that of PM2.5 concentration, as well as changes in elevation. The topography was also an important factor in the accumulation of PM2.5 in CC. Moreover, the most polluted urban agglomeration based on the population-weighted mean was BTH, while the least was PRD. In terms of the cumulative percent distribution, only 0.51% of the population who lived in the four urban agglomerations, and 2.33% of the GDP that was produced in the four urban agglomerations, were associated with an annual PM2.5 concentration smaller than the Chinese National Ambient Air Quality Standard of 35 µg/m3. This indicates that the majority of people live in the high air polluted areas, and economic development contributes to air pollution. Our results are supported by the high correlation between population exposure and the corresponding GDP in each urban agglomeration. PMID:28671643

Volcanic ash layers illuminate the resilience of Neanderthals and early modern humans to natural hazards

PubMed Central

Lowe, John; Barton, Nick; Blockley, Simon; Ramsey, Christopher Bronk; Cullen, Victoria L.; Davies, William; Gamble, Clive; Grant, Katharine; Hardiman, Mark; Housley, Rupert; Lane, Christine S.; Lee, Sharen; Lewis, Mark; MacLeod, Alison; Menzies, Martin; Müller, Wolfgang; Pollard, Mark; Price, Catherine; Roberts, Andrew P.; Rohling, Eelco J.; Satow, Chris; Smith, Victoria C.; Stringer, Chris B.; Tomlinson, Emma L.; White, Dustin; Albert, Paul; Arienzo, Ilenia; Barker, Graeme; Borić, Dušan; Carandente, Antonio; Civetta, Lucia; Ferrier, Catherine; Guadelli, Jean-Luc; Karkanas, Panagiotis; Koumouzelis, Margarita; Müller, Ulrich C.; Orsi, Giovanni; Pross, Jörg; Rosi, Mauro; Shalamanov-Korobar, Ljiljiana; Sirakov, Nikolay; Tzedakis, Polychronis C.

2012-01-01

Marked changes in human dispersal and development during the Middle to Upper Paleolithic transition have been attributed to massive volcanic eruption and/or severe climatic deterioration. We test this concept using records of volcanic ash layers of the Campanian Ignimbrite eruption dated to ca. 40,000 y ago (40 ka B.P.). The distribution of the Campanian Ignimbrite has been enhanced by the discovery of cryptotephra deposits (volcanic ash layers that are not visible to the naked eye) in archaeological cave sequences. They enable us to synchronize archaeological and paleoclimatic records through the period of transition from Neanderthal to the earliest anatomically modern human populations in Europe. Our results confirm that the combined effects of a major volcanic eruption and severe climatic cooling failed to have lasting impacts on Neanderthals or early modern humans in Europe. We infer that modern humans proved a greater competitive threat to indigenous populations than natural disasters. PMID:22826222

Phenol-photodegradation on ZrO2. Enhancement by semiconductors.

PubMed

Karunakaran, C; Dhanalakshmi, R; Gomathisankar, P

2012-06-15

On illumination with light of wavelength 365 nm phenol undergoes degradation on the surface of ZrO(2). The rate of degradation enhances linearly with the concentration of phenol and also the light intensity but decreases with increase of pH. The photonic efficiency of degradation is higher with illumination at 254 nm than with 365 nm. The diffuse reflectance spectral study suggests phenol-sensitized activation of ZrO(2) with 365 nm light. TiO(2), Fe(2)O(3), CuO, ZnO, ZnS, Nb(2)O(5) and CdO particles enhance the photodegradation on ZrO(2), indicating inter-particle charge-transfer. Determination of size of the particles under suspension, by light scattering technique, shows agglomeration of particles supporting the proposition of charge-transfer between particles. Copyright © 2012 Elsevier B.V. All rights reserved.

Nested high-resolution modeling of the impact of urbanization on regional climate in three vast urban agglomerations in China

NASA Astrophysics Data System (ADS)

Wang, Jun; Feng, Jinming; Yan, Zhongwei; Hu, Yonghong; Jia, Gensuo

2012-11-01

In this paper, the Weather Research and Forecasting Model, coupled to the Urban Canopy Model, is employed to simulate the impact of urbanization on the regional climate over three vast city agglomerations in China. Based on high-resolution land use and land cover data, two scenarios are designed to represent the nonurban and current urban land use distributions. By comparing the results of two nested, high-resolution numerical experiments, the spatial and temporal changes on surface air temperature, heat stress index, surface energy budget, and precipitation due to urbanization are analyzed and quantified. Urban expansion increases the surface air temperature in urban areas by about 1°C, and this climatic forcing of urbanization on temperature is more pronounced in summer and nighttime than other seasons and daytime. The heat stress intensity, which reflects the combined effects of temperature and humidity, is enhanced by about 0.5 units in urban areas. The regional incoming solar radiation increases after urban expansion, which may be caused by the reduction of cloud fraction. The increased temperature and roughness of the urban surface lead to enhanced convergence. Meanwhile, the planetary boundary layer is deepened, and water vapor is mixed more evenly in the lower atmosphere. The deficit of water vapor leads to less convective available potential energy and more convective inhibition energy. Finally, these combined effects may reduce the rainfall amount over urban areas, mainly in summer, and change the regional precipitation pattern to a certain extent.

Nested High Resolution Modeling of the Impact of Urbanization on Regional Climate in Three Vast Urban Agglomerations in China

NASA Astrophysics Data System (ADS)

Wang, Jun; Feng, Jinming; Yan, Zhongwei; Hu, Yonghong; Jia, Gensuo

2013-04-01

In this paper, the Weather Research and Forecasting (WRF) model coupled to the Urban Canopy Model (UCM) is employed to simulate the impact of urbanization on the regional climate over three vast city agglomerations in China. Based on high resolution land use and land cover data, two scenarios are designed to represent the non-urban and current urban land use distributions. By comparing the results of two nested, high resolution numerical experiments, the spatial and temporal changes on surface air temperature, heat stress index, surface energy budget and precipitation due to urbanization are analyzed and quantified. Urban expansion increases the surface air temperature in urban areas by about 1? and this climatic forcing of urbanization on temperature is more pronounced in summer and nighttime than other seasons and daytime. The heat stress intensity, which reflects the combined effects of temperature and humidity, is enhanced by about 0.5 units in urban areas. The regional incoming solar radiation increases after urban expansion, which may be caused by the reduction of cloud fraction. The increased temperature and roughness of the urban surface lead to enhanced convergence. Meanwhile, the planetary boundary layer is deepened and water vapor is mixed more evenly in the lower atmosphere. The deficit of water vapor leads to less convective available potential energy and more convective inhibition energy. Finally, these combined effects may reduce the rainfall amount over urban area mainly in summer and change the regional precipitation pattern to a certain extent.

Directional Agglomeration Multigrid Techniques for High Reynolds Number Viscous Flow Solvers

NASA Technical Reports Server (NTRS)

1998-01-01

A preconditioned directional-implicit agglomeration algorithm is developed for solving two- and three-dimensional viscous flows on highly anisotropic unstructured meshes of mixed-element types. The multigrid smoother consists of a pre-conditioned point- or line-implicit solver which operates on lines constructed in the unstructured mesh using a weighted graph algorithm. Directional coarsening or agglomeration is achieved using a similar weighted graph algorithm. A tight coupling of the line construction and directional agglomeration algorithms enables the use of aggressive coarsening ratios in the multigrid algorithm, which in turn reduces the cost of a multigrid cycle. Convergence rates which are independent of the degree of grid stretching are demonstrated in both two and three dimensions. Further improvement of the three-dimensional convergence rates through a GMRES technique is also demonstrated.

Directional Agglomeration Multigrid Techniques for High-Reynolds Number Viscous Flows

NASA Technical Reports Server (NTRS)

Mavriplis, Dimitri J.

1998-01-01

A preconditioned directional-implicit agglomeration algorithm is developed for solving two- and three-dimensional viscous flows on highly anisotropic unstructured meshes of mixed-element types. The multigrid smoother consists of a pre-conditioned point- or line-implicit solver which operates on lines constructed in the unstructured mesh using a weighted graph algorithm. Directional coarsening or agglomeration is achieved using a similar weighted graph algorithm. A tight coupling of the line construction and directional agglomeration algorithms enables the use of aggressive coarsening ratios in the multigrid algorithm, which in turn reduces the cost of a multigrid cycle. Convergence rates which are independent of the degree of grid stretching are demonstrated in both two and three dimensions. Further improvement of the three-dimensional convergence rates through a GMRES technique is also demonstrated.

Standardization and quality control parameters for Muktā Bhasma (calcined pearl)

PubMed Central

Joshi, Namrata; Sharma, Khemchand; Peter, Hema; Dash, Manoj Kumar

2015-01-01

Background: Muktā Bhasma (MB) is a traditional Ayurvedic preparation for cough, breathlessness, and eye disorders and is a powerful cardiac tonic, mood elevator, and known to promote strength, intellect, and semen production. Objectives: The present research work was conducted to generate fingerprint for raw and processed MB for quality assessment and standardization using classical and other techniques. Setting and Design: Three samples of MB were prepared by purification (śodhana) of Muktā (pearl) followed by repeated calcinations (Māraṇa). Resultant product was subjected to organoleptic tests and Ayurvedic tests for quality control such as rekhāpūrṇatā, vāritaratva, and nirdhūmatva. Materials and Methods: For quality control, physicochemical parameters such as loss on drying, total ash value, acid insoluble ash, specific gravity, pH value, and other tests using techniques such as elemental analysis with energy dispersive X-ray analysis (EDAX), Structural study with powder X-ray diffraction, particle size with scanning electron microscopy (SEM) were carried out on raw Muktā, Śodhita Muktā, and triplicate batches of MB. Results: The study showed that the raw material Muktā was calcium carbonate in aragonite form, which on repeated calcinations was converted into a more stable calcite form. SEM studies revealed that in raw and purified materials the particles were found scattered and unevenly arranged in the range of 718.7–214.7 nm while in final product, uniformly arranged, stable, rod-shaped, and rounded particles with more agglomerates were observed in the range of 279.2–79.93 nm. EDAX analysis revealed calcium as a major ingredient in MB (average 46.32%) which increased gradually in the stages of processing (raw 34.11%, Śodhita 37.5%). Conclusion: Quality control parameters have been quantified for fingerprinting of MB prepared using a particular method. PMID:26600667

Structural study of graphite materials prepared by HTT of unburned carbon concentrates from coal combustion fly ashes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miguel Cabielles; Miguel A. Montes-Moran; Ana B. Garcia

2008-03-15

Unburned carbon concentrates with different mineral matter contents were obtained from coal combustion fly ashes by an oil agglomeration procedure. The concentrates were then heated in the temperature interval 1800-2700{sup o}C for the purpose of exploring their ability to graphitize. The influence of the treatment temperature and mineral matter of the unburned carbon on the structural characteristics of the materials prepared was studied. The interlayer spacing, d{sub 002}, and crystallite sizes along the c-axis, L{sub c}, and the {alpha}-axis, L{sub a}, calculated from X-ray diffractometry (XRD) as well as the relative intensity of the Raman D-band, I{sub D}/I{sub t}, weremore » used to assess the degree of structural order of the materials. Graphite materials with structural characteristics comparable to those of other oil-derived synthetic graphites were prepared from the unburned carbon concentrates at temperatures {>=}2400{sup o}C. It was also observed that more-ordered materials were obtained from the unburned carbon concentrates with higher mineral matter content. The influence of the mineral matter on the graphitization of the unburned carbon concentrates is the result of two countereffects, thus limiting its extent. On the one hand, the lateral coalescence of the crystallites is preferentially promoted. Reasonably good linear correlations were attained between the mineral matter of the unburned carbon concentrate and the XRD parameter L{sub a} of the materials. However, on the other, this coalescence also facilitates the flattening of the pores, thus decreasing the temperature at which their breakage occurs. As a consequence, from this point on, the structural evolution of the materials with increasing mineral matter is only noticeable by the slow vegetative growth of the crystallites along the a-axis. 40 refs., 2 figs., 3 tabs.« less

Treatability of stabilize landfill leachate by using pressmud ash as an adsorbent

NASA Astrophysics Data System (ADS)

Azme, N. N. Mohd; Murshed, M. F.

2018-04-01

Leachate is a liquid produced from the landfill that contains high concentration of heavy metals, chemicals and nutrient loading. The treatability of these contaminants are complicated since the current treatment technology are costly and site specific. Therefore, this study was conducted to evaluate the treatability of stabilized landfill leachate by using waste (pressmud ash) as an absorbent. Pressmud ash was prepared by burning at different temperature from 100 to 700 degree Celsius and test at 24 hours shaking time, pH 8, and 4000 rpm. Leachate samples were collected from municipal solid waste (MSW) Pulau Burung Sanitary Landfill (PBSL) and were analyzed for heavy metal, COD, ammonia and colour. This study was performed in two phases i) leachate characteristic, ii) treatability assessment by using pressmud ash. Pressmud was sampled from the sugar mill, Malaysian Sugar Manufacturing (MSM) Sdn Bhd, Seberang Perai, Pulau Pinang. The pressmud with 400°C are highly potential material with a low cost which can be a good adsorbent was capable reducing efficiencies of COD (60.76%), ammonia (64.37%) and colour (35.78%) from real wastewater leachate. Pressmud showed good sorption capability. Surface modification with burning greatly enhanced the reducing efficiency of sugar waste based adsorbent with adsorption efficiency.

Investigation of the interaction of ferromagnetic fluids with proteins by dynamic light scattering

NASA Astrophysics Data System (ADS)

Velichko, Elena; Nepomnyashchaya, Elina; Dudina, Alina; Pleshakov, Ivan; Aksenov, Evgenii

2018-04-01

In this article the interaction between ionically stabilized magnetic nanoparticles and blood serum albumin proteins in liquid medium are discussed. Some distributions of nanoparticles' agglomerate sizes in solutions of albumin molecules, magnetic nanoparticles and their mixtures both under the influence of magnetic field and free from it are presented. It is shown that magnetic nanoparticles interact with albumin molecules, forming agglomerates. It is also shown that at the influence of magnetic field sizes of agglomerates increase proportionally to the magnetic field density.

Transport and Deposition of Welding Fume Agglomerates in a Realistic Human Nasal Airway.

PubMed

Tian, Lin; Inthavong, Kiao; Lidén, Göran; Shang, Yidan; Tu, Jiyuan

2016-07-01

Welding fume is a complex mixture containing ultra-fine particles in the nanometer range. Rather than being in the form of a singular sphere, due to the high particle concentration, welding fume particles agglomerate into long straight chains, branches, or other forms of compact shapes. Understanding the transport and deposition of these nano-agglomerates in human respiratory systems is of great interest as welding fumes are a known health hazard. The neurotoxin manganese (Mn) is a common element in welding fumes. Particulate Mn, either as soluble salts or oxides, that has deposited on the olfactory mucosa in human nasal airway is transported along the olfactory nerve to the olfactory bulb within the brain. If this Mn is further transported to the basal ganglia of the brain, it could accumulate at the part of the brain that is the focal point of its neurotoxicity. Accounting for various dynamic shape factors due to particle agglomeration, the current computational study is focused on the exposure route, the deposition pattern, and the deposition efficiency of the inhaled welding fume particles in a realistic human nasal cavity. Particular attention is given to the deposition pattern and deposition efficiency of inhaled welding fume agglomerates in the nasal olfactory region. For particles in the nanoscale, molecular diffusion is the dominant transport mechanism. Therefore, Brownian diffusion, hydrodynamic drag, Saffman lift force, and gravitational force are included in the model study. The deposition efficiencies for single spherical particles, two kinds of agglomerates of primary particles, two-dimensional planar and straight chains, are investigated for a range of primary particle sizes and a range of number of primary particles per agglomerate. A small fraction of the inhaled welding fume agglomerates is deposited on the olfactory mucosa, approximately in the range 0.1-1%, and depends on particle size and morphology. The strong size dependence of the deposition in olfactory mucosa on particle size implies that the occupation deposition of welding fume manganese can be expected to vary with welding method. © The Author 2016. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Strength and fracture energy of foamed concrete incorporating rice husk ash and polypropylene mega-mesh 55

NASA Astrophysics Data System (ADS)

Jaini, Z. M.; Rum, R. H. M.; Boon, K. H.

2017-10-01

This paper presents the utilization of rice husk ash (RHA) as sand replacement and polypropylene mega-mesh 55 (PMM) as fiber reinforcement in foamed concrete. High pozzolanic reaction and the ability to become filler make RHA as a strategic material to enhance the strength and durability of foamed concrete. Furthermore, the presence of PMM optimizes the toughness of foamed concrete in resisting shrinkage and cracking. In this experimental study, cube and cylinder specimens were prepared for the compression and splitting-tensile tests. Meanwhile, notched beam specimens were cast for the three-point bending test. It was found that 40% RHA and 9kg/m3 PMM contribute to the highest strength and fracture energy. The compressive, tensile and flexural strengths are 32MPa, 2.88MPa and 6.68MPa respectively, while the fracture energy achieves 42.19N/m. The results indicate high potential of RHA and PMM in enhancing the mechanical properties of foamed concrete.

A Comprehensive Study of the Polypropylene Fiber Reinforced Fly Ash Based Geopolymer

PubMed Central

Ranjbar, Navid; Mehrali, Mehdi; Behnia, Arash; Javadi Pordsari, Alireza; Mehrali, Mohammad; Alengaram, U. Johnson; Jumaat, Mohd Zamin

2016-01-01

As a cementitious material, geopolymers show a high quasi-brittle behavior and a relatively low fracture energy. To overcome such a weakness, incorporation of fibers to a brittle matrix is a well-known technique to enhance the flexural properties. This study comprehensively evaluates the short and long term impacts of different volume percentages of polypropylene fiber (PPF) reinforcement on fly ash based geopolymer composites. Different characteristics of the composite were compared at fresh state by flow measurement and hardened state by variation of shrinkage over time to assess the response of composites under flexural and compressive load conditions. The fiber-matrix interface, fiber surface and toughening mechanisms were assessed using field emission scan electron microscopy (FESEM) and atomic force microscopy (AFM). The results show that incorporation of PPF up to 3 wt % into the geopolymer paste reduces the shrinkage and enhances the energy absorption of the composites. While, it might reduce the ultimate flexural and compressive strength of the material depending on fiber content. PMID:26807825

A Comprehensive Study of the Polypropylene Fiber Reinforced Fly Ash Based Geopolymer.

PubMed

Ranjbar, Navid; Mehrali, Mehdi; Behnia, Arash; Javadi Pordsari, Alireza; Mehrali, Mohammad; Alengaram, U Johnson; Jumaat, Mohd Zamin

2016-01-01

As a cementitious material, geopolymers show a high quasi-brittle behavior and a relatively low fracture energy. To overcome such a weakness, incorporation of fibers to a brittle matrix is a well-known technique to enhance the flexural properties. This study comprehensively evaluates the short and long term impacts of different volume percentages of polypropylene fiber (PPF) reinforcement on fly ash based geopolymer composites. Different characteristics of the composite were compared at fresh state by flow measurement and hardened state by variation of shrinkage over time to assess the response of composites under flexural and compressive load conditions. The fiber-matrix interface, fiber surface and toughening mechanisms were assessed using field emission scan electron microscopy (FESEM) and atomic force microscopy (AFM). The results show that incorporation of PPF up to 3 wt % into the geopolymer paste reduces the shrinkage and enhances the energy absorption of the composites. While, it might reduce the ultimate flexural and compressive strength of the material depending on fiber content.

Floating cultivation of marine cyanobacteria using coal fly ash.

PubMed

Matsumoto, M; Yoshida, E; Takeyama, H; Matsunaga, T

2000-01-01

The aim of this study was to develop improved methodologies for bulk culturing of biotechnologically useful marine cyanobacteria in the open ocean. We have investigated the viability of using coal fly ash (CFA) blocks as the support medium in a novel floating culture system for marine micro-algae. The marine cyanobacterium Synechococcus sp. NKBG 040607 was found to adhere to floating CFA blocks in liquid culture medium. Maximum density of attached cells of 2.0 x 10(8) cells/cm2 was achieved using seawater. The marine cyanobacterium Synechococcus sp. NKBG 042902 weakly adhered to floating CFA blocks in BG-11 medium. Increasing the concentration of calcium ion in the culture medium enhanced adherence to CFA blocks.

Satellite-Based Tropospheric NO2 Column Trends in the Last 10 Years Over Mexican Urban Areas Measured by the Ozone Monitoring Instrument

NASA Astrophysics Data System (ADS)

Rivera, C. I.; Stremme, W.; Grutter, M.

2015-12-01

Population density and economic activities in urban agglomerations have drastically increased in many cities in Mexico during the last decade. Several factors are responsible for increased urbanization such as a shift of people from rural to urban areas while looking for better education, services and job opportunities as well as the natural growth of the urban areas themselves. Urbanization can create great social, economic and environmental pressures and changes which can easily be observed in most urban agglomerations in the world. In this study, we have focused on analyzing tropospheric NO2 (nitrogen dioxide) column trends over Mexican urban areas that have a population of at least one million inhabitants according to the latest 2010 population census. Differential Optical Absorption Spectroscopy (DOAS) measurements of NO2 conducted by the space-borne Ozone Monitoring Instrument (OMI) on board the Aura satellite between 2005 and 2014 have been used for this analysis. This dataset has allowed us to obtain a satellite-based 10-year tropospheric NO2 column trend over the most populated Mexican cities which include the dominating metropolitan area of Mexico City with more than twenty million inhabitants as well as ten other Mexican cities with a population ranging between one to five million inhabitants with a wide range of activities (commercial, agricultural or heavily industrialized) as well as two important border crossings. Distribution maps of tropospheric NO2 columns above the studied urban agglomerations were reconstructed from the analyzed OMI dataset, allowing to identify areas of interest due to clear NO2 enhancements inside these urban regions.

Durability Improvement of Pt/RGO Catalysts for PEMFC by Low-Temperature Self-Catalyzed Reduction.

PubMed

Sun, Kang Gyu; Chung, Jin Suk; Hur, Seung Hyun

2015-12-01

Pt/C catalyst used for polymer electrolyte membrane fuel cells (PEMFCs) displays excellent initial performance, but it does not last long because of the lack of durability. In this study, a Pt/reduced graphene oxide (RGO) catalyst was synthesized by the polyol method using ethylene glycol (EG) as the reducing agent, and then low-temperature hydrogen bubbling (LTHB) treatment was introduced to enhance the durability of the Pt/RGO catalyst. The cyclic voltammetry (CV), oxygen reduction reaction (ORR) analysis, and transmittance electron microscopy (TEM) results suggested that the loss of the oxygen functional groups, because of the hydrogen spillover and self-catalyzed dehydration reaction during LTHB, reduced the carbon corrosion and Pt agglomeration and thus enhanced the durability of the electrocatalyst.

Acoustic agglomeration methods and apparatus

NASA Technical Reports Server (NTRS)

Barmatz, M. B. (Inventor)

1984-01-01

Methods are described for using acoustic energy to agglomerate fine particles on the order of one micron diameter that are suspended in gas, to provide agglomerates large enough for efficient removal by other techniques. The gas with suspended particles, is passed through the length of a chamber while acoustic energy at a resonant chamber mode is applied to set up one or more acoustic standing wave patterns that vibrate the suspended particles to bring them together so they agglomerate. Several widely different frequencies can be applied to efficiently vibrate particles of widely differing sizes. The standing wave pattern can be applied along directions transversed to the flow of the gas. The particles can be made to move in circles by applying acoustic energy in perpendicular directions with the energy in both directions being of the same wavelength but 90 deg out of phase.

A comparison of dispersing media for various engineered carbon nanoparticles.

PubMed

Buford, Mary C; Hamilton, Raymond F; Holian, Andrij

2007-07-27

With the increased manufacture and use of carbon nanoparticles (CNP) there has been increasing concern about the potential toxicity of fugitive CNP in the workplace and ambient environment. To address this matter a number of investigators have conducted in vitro and in vivo toxicity assessments. However, a variety of different approaches for suspension of these particles (culture media, Tween 80, dimethyl sulfoxide, phosphate-buffered saline, fetal calf serum, and others), and different sources of materials have generated potentially conflicting outcomes. The quality of the dispersion of nanoparticles is very dependent on the medium used to suspend them, and this then will most likely affect the biological outcomes. In this work, the distributions of different CNP (sources and types) have been characterized in various media. Furthermore, the outcome of instilling the different agglomerates, or size distributions, was examined in mouse lungs after one and seven days. Our results demonstrated that CNP suspended in serum produced particle suspensions with the fewest large agglomerates, and the most uniform distribution in mouse lungs. In addition, no apparent clearance of instilled CNP took place from lungs even after seven days. This work demonstrates that CNP agglomerates are present in all dispersing vehicles to some degree. The vehicle that contains some protein, lipid or protein/lipid component disperses the CNP best, producing fewer large CNP agglomerates. In contrast, vehicles absent of lipid and protein produce the largest CNP agglomerates. The source of the CNP is also a factor in the degree of particle agglomeration within the same vehicle.

A discrete element and ray framework for rapid simulation of acoustical dispersion of microscale particulate agglomerations

NASA Astrophysics Data System (ADS)

Zohdi, T. I.

2016-03-01

In industry, particle-laden fluids, such as particle-functionalized inks, are constructed by adding fine-scale particles to a liquid solution, in order to achieve desired overall properties in both liquid and (cured) solid states. However, oftentimes undesirable particulate agglomerations arise due to some form of mutual-attraction stemming from near-field forces, stray electrostatic charges, process ionization and mechanical adhesion. For proper operation of industrial processes involving particle-laden fluids, it is important to carefully breakup and disperse these agglomerations. One approach is to target high-frequency acoustical pressure-pulses to breakup such agglomerations. The objective of this paper is to develop a computational model and corresponding solution algorithm to enable rapid simulation of the effect of acoustical pulses on an agglomeration composed of a collection of discrete particles. Because of the complex agglomeration microstructure, containing gaps and interfaces, this type of system is extremely difficult to mesh and simulate using continuum-based methods, such as the finite difference time domain or the finite element method. Accordingly, a computationally-amenable discrete element/discrete ray model is developed which captures the primary physical events in this process, such as the reflection and absorption of acoustical energy, and the induced forces on the particulate microstructure. The approach utilizes a staggered, iterative solution scheme to calculate the power transfer from the acoustical pulse to the particles and the subsequent changes (breakup) of the pulse due to the particles. Three-dimensional examples are provided to illustrate the approach.

Particle agglomeration and fuel decomposition in burning slurry droplets

NASA Astrophysics Data System (ADS)

Choudhury, P. Roy; Gerstein, Melvin

In a burning slurry droplet the particles tend to agglomerate and produce large clusters which are difficult to burn. As a consequence, the combustion efficiency is drastically reduced. For such a droplet the nonlinear D2- t behavior associated with the formation of hard to burn agglomerates can be explained if the fuel decomposes on the surface of the particles. This paper deals with analysis and experiments with JP-10 and Diesel #2 slurries prepared with inert SiC and Al 2O 3 particles. It provides direct evidence of decomposed fuel residue on the surface of the particles heated by flame radiation. These decomposed fuel residues act as bonding agents and appear to be responsible for the observed agglomeration of particles in a slurry. Chemical analysis, scanning electron microscope photographs and finally micro-analysis by electron scattering clearly show the presence of decomposed fuel residue on the surface of the particles. Diesel #2 is decomposed relatively easily and therefore leaves a thicker deposit on SiC and forms larger agglomerates than the more stable JP-10. A surface reaction model with particles heated by flame radiation is able to describe the observed trend of the diameter history of the slurry fuel. Additional experiments with particles of lower emissivity (Al 2O 3) and radiation absorbing dye validate the theoretical model of the role of flame radiation in fuel decomposition and the formation of agglomerates in burning slurry droplets.

Water-extractable and water-unextractable arabinoxylans affect gluten agglomeration behavior during wheat flour gluten-starch separation.

PubMed

Frederix, Sofie A; Van Hoeymissen, Klaartje E; Courtin, Christophe M; Delcour, Jan A

2004-12-29

Water-extractable arabinoxylan (WE-AX) of variable molecular weight (MW) and water-unextractable arabinoxylan (WU-AX) were added to wheat flour to study their effect on gluten agglomeration in a dough and batter gluten-starch separation process with recovery of gluten from the batter with a set of vibrating sieves (400, 250, and 125 microm). Low MW WE-AX had almost no impact on the distribution of the gluten on the different sieves. High MW WE-AX decreased yields of the largest (400 microm sieve) gluten aggregates, more than their medium MW counterparts, indicating the importance of AX MW for their effect on gluten interactions. Correlations between the total level of gluten protein recovered on the three sieves and the batter extract viscosity as well as between the proportion of gluten protein recovered on the 400 microm sieve to that on the three sieves and the batter extract viscosity pointed to the importance of viscosity as an indicator for gluten agglomeration, as did the fact that another viscosity increasing plant polysaccharide (guar gum) also negatively influenced gluten agglomeration. However, the obtained data cannot rule out that AX and guar gum also exert steric effects on gluten agglomeration. WU-AX, present as discrete cell wall fragments, had a negative impact on the level of large gluten aggregates. Taken together, the results show that both native WE-AX and WU-AX detrimentally impact gluten agglomeration.

Perspective usage estimation of Volga region combustible shale as a power generating fuel alternative

NASA Astrophysics Data System (ADS)

Korolev, E.; Barieva, E.; Eskin, A.

2018-05-01

A comprehensive study of combustible shale, common within Tatarstan and Ulyanovsk region, is carried out. The rocks physicochemical parameters are found to meet the power generating fuels requirements. The predictive estimate of ash products properties of combustible shale burning is held. Minding furnace process technology it is necessary to know mineral and organic components behavior when combustible shale is burnt. Since the first will determine slagging properties of energy raw materials, the second – its calorific value. In consideration of this the main research methods were X-ray, thermal and X-ray fluorescence analyses. Summing up the obtained results, we can draw to the following conclusions: 1. The combustible shale in Tatarstan and the Ulyanovsk region has predominantly low calorific value (Qb d = 5-9 MJ/kg). In order to enhance its efficiency and to reduce cost it is possible to conduct rocks burning together with some other organic or organic mineral power generating fuels. 2. High ash content (Ad = 60-80%) that causes a high external ballast content in shale implies the appropriateness of using this fuel resource next to its exploitation site. The acceptable distance to a consumer will reduce unproductive transportation charges for large ash and moisture masses. 3. The performed fuel ash components characteristics, as well as the yield and volatiles composition allow us to specify the basic parameters for boiler units, designed for the Volga combustible shale burning. 4. The noncombustible residual components composition shows that shale ash can be used in manufacture of materials of construction.

Water conservation features of ova of Agrilus planipennis (Coleoptera: Buprestidae).

PubMed

Rigsby, Chad M; Cipollini, Don; Amstutz, Evan M; Smith, Terrance J; Yoder, Jay A

2013-04-01

The emerald ash borer, Agrilus planipennis Fairmaire, has destroyed millions of ash trees (Fraxinus spp.) in North America since first identified in Detroit in 2002. With species of ash distributed throughout North America, it is easy to speculate the extinction of all susceptible species of ash on the continent given a lack of physical, environmental, or climactic barrier for dispersal of the insect. We investigated water balance characteristics of emerald ash borer ova by using gravimetric methods in an effort to measure their response to heat- and water-stress and explore possible influences this stress may have on the ecology and physiology of the ovum. We also explored the possible water balance benefit of a peculiar, "clustering," oviposition behavior, as well as the difference in responses to stress between ova from a laboratory colony and ova from two wild populations. We found no evidence of water vapor absorption as a water balance strategy; rather enhanced water retention, resistance to desiccation, and viability with low water content were important survival strategies for these ova. Surface lipids resist thermal breakdown as indicated by ova having no detectable critical transition temperature, maintaining their water-proofing function as temperature rises. The observed "clustering" behavior had no desiccation-avoidance benefit and ova from the wild populations behaved almost identically to the ova from the lab colony, although the lab ova were slightly larger and more sensitive to dehydration. Given this new information, there appears to be no heat- or water-stress barriers for the dispersal of this devastating pest at the ovum stage.

Improving lithium-ion battery performances by adding fly ash from coal combustion on cathode film

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dyartanti, Endah Retno; Jumari, Arif, E-mail: arifjumari@yahoo.com; Nur, Adrian

A lithium battery is composed of anode, cathode and a separator. The performance of lithium battery is also influenced by the conductive material of cathode film. In this research, the use of fly ash from coal combustion as conductive enhancer for increasing the performances of lithium battery was investigated. Lithium iron phosphate (LiFePO{sub 4}) was used as the active material of cathode. The dry fly ash passed through 200 mesh screen, LiFePO{sub 4} and acethylene black (AB), polyvinylidene fluoride (PVDF) as a binder and N-methyl-2-pyrrolidone (NMP) as a solvent were mixed to form slurry. The slurry was then coated, driedmore » and hot pressed to obtain the cathode film. The ratio of fly ash and AB were varied at the values of 1%, 2%, 3%, 4% and 5% while the other components were at constant. The anode film was casted with certain thickness and composition. The performance of battery lithium was examined by Eight Channel Battery Analyzer, the composition of the cathode film was examined by XRD (X-Ray Diffraction), and the structure and morphology of the anode film was analyzed by SEM (Scanning Electron Microscope). The composition, structure and morphology of cathode film was only different when fly ash added was 4% of AB or more. The addition of 2% of AB on cathode film gave the best performance of 81.712 mAh/g on charging and 79.412 mAh/g on discharging.« less

Enhancing the compressive strength of landfill soil using cement and bagasse ash

NASA Astrophysics Data System (ADS)

Azim, M. A. M.; Azhar, A. T. S.; Tarmizi, A. K. A.; Shahidan, S.; Nabila, A. T. A.

2017-11-01

The stabilisation of contaminated soil with cement and agricultural waste is a widely applied method which contributes to the sustainability of the environment. Soil may be stabilised to increase strength and durability or to prevent erosion and other geotechnical failure. This study was carried out to evaluate the compressive strength of ex-landfill soil when cement and bagasse ash (BA) are added to it. Different proportions of cement (5%, 10%, 15% and 20%) was added to sample weights without BA. On the other hand, the cement in a different batch of sample weights was replaced by 2.5%, 5%, 7.5% and 10% of BA. All samples were allowed to harden and were cured at room temperature for 7, 14 and 28 days respectively. The strength of the contaminated soil was assessed using an unconfined compressive strength test (UCS). The laboratory tests also included the index properties of soil, cement and bagasse ash in raw form. The results indicated that the samples with cement achieved the highest compressive strength measuring 4.39 MPa. However, this study revealed that the use of bagasse ash produced low quality products with a reduction in strength. For example, when 5% of cement was replaced with 5% ash, the compressive strength decreased by about 54% from 0.72 MPa to 0.33 MPa. Similarly, the compressive strength of each sample after a curing period of 28 days was higher compared to samples cured for 7 and 14 days respectively. This is proved that a longer curing period is needed to increase the compressive strength of the samples.

Unsaturated flow processes in structurally-variable pathways in wildfire-affected soils and ash

NASA Astrophysics Data System (ADS)

Ebel, B. A.

2016-12-01

Prediction of flash flood and debris flow generation in wildfire-affected soils and ash hinges on understanding unsaturated flow processes. Water resources issues, such as groundwater recharge, also rely on our ability to quantify subsurface flow. Soil-hydraulic property data provide insight into unsaturated flow processes and timescales. A literature review and synthesis of existing data from the literature for wildfire-affected soils, including ash and unburned soils, facilitated calculating metrics and timescales of hydrologic response related to infiltration and surface runoff generation. Sorptivity (S) and the Green-Ampt wetting front parameter (Ψf) were significantly lower in burned soils compared to unburned soils, while field-saturated hydraulic conductivity (Kfs) was not significantly different. The magnitude and duration of the influence of capillarity was substantially reduced in burned soils, leading to faster ponding times in response to rainfall. Ash had large values of S and Kfs compared to unburned and burned soils but intermediate values of Ψf, suggesting that ash has long ponding times in response to rainfall. The ratio of S2/Kfs was nearly constant ( 100 mm) for unburned soils, but was more variable in burned soils. Post-wildfire changes in this ratio suggested that unburned soils had a balance between gravity and capillarity contributions to infiltration, which may depend on soil organic matter, while burning shifted infiltration more towards gravity contributions by reducing S. Taken together, the changes in post-wildfire soil-hydraulic properties increased the propensity for surface runoff generation and may have enhanced subsurface preferential flow through pathways altered by wildfire.

Carbon Nanotube Purification and Functionalization

NASA Technical Reports Server (NTRS)

Lebron, Marisabel; Mintz, Eric; Smalley, Richard E.; Meador, Michael A.

2003-01-01

Carbon nanotubes have the potential to significantly enhance the mechanical, thermal, and electrical properties of polymers. However, dispersion of carbon nanotubes in a polymer matrix is hindered by the electrostatic forces that cause them to agglomerate. Chemical modification of the nanotubes is necessary to minimize these electrostatic forces and promote adhesion between the nanotubes and the polymer matrix. In a collaborative research program between Clark Atlanta University, Rice University, and NASA Glenn Research Center several approaches are being explored to chemically modify carbon nanotubes. The results of this research will be presented.

Two-stage agglomeration of fine-grained herbal nettle waste

NASA Astrophysics Data System (ADS)

Obidziński, Sławomir; Joka, Magdalena; Fijoł, Olga

2017-10-01

This paper compares the densification work necessary for the pressure agglomeration of fine-grained dusty nettle waste, with the densification work involved in two-stage agglomeration of the same material. In the first stage, the material was pre-densified through coating with a binder material in the form of a 5% potato starch solution, and then subjected to pressure agglomeration. A number of tests were conducted to determine the effect of the moisture content in the nettle waste (15, 18 and 21%), as well as the process temperature (50, 70, 90°C) on the values of densification work and the density of the obtained pellets. For pre-densified pellets from a mixture of nettle waste and a starch solution, the conducted tests determined the effect of pellet particle size (1, 2, and 3 mm) and the process temperature (50, 70, 90°C) on the same values. On the basis of the tests, we concluded that the introduction of a binder material and the use of two-stage agglomeration in nettle waste densification resulted in increased densification work (as compared to the densification of nettle waste alone) and increased pellet density.

Uniformly Dispersed and Re-Agglomerated Graphene Oxide-Based Cement Pastes: A Comparison of Rheological Properties, Mechanical Properties and Microstructure.

PubMed

Long, Wu-Jian; Li, Hao-Dao; Fang, Chang-Le; Xing, Feng

2018-01-09

The properties of graphene oxide (GO)-based cement paste can be significantly affected by the state of GO dispersion. In this study, the effects of uniformly dispersed and re-agglomerated GO on the rheological, mechanical properties and microstructure of cement paste were systematically investigated. Two distinct dispersion states can be achieved by altering the mixing sequence: Polycarboxylate-ether (PCE) mixed with GO-cement or cement mixed with GO-PCE. The experimental results showed that the yield stress and plastic viscosity increased with the uniformly dispersed GO when compared to those of re-agglomerated GO cement paste. Moreover, the 3-day compressive and flexural strengths of uniformly dispersed GO paste were 8% and 27%, respectively, higher than those of re-agglomerated GO pastes. The results of X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy analyses demonstrated that uniformly dispersed GO more effectively promotes the formation of hydration products in hardened cement paste. Furthermore, a porosity analysis using mercury intrusion porosimetry revealed that the homogeneous dispersion of GO can better inhibit the formation of large-size pores and optimize the pore size distribution at 3 and 7 days than the re-agglomerated GO.

Leukocyte Agglomeration Reaction in Diagnosis of Allergy Reactions from Antibiotics,

DTIC Science & Technology

tested in a clinic on 80 patients with serious allergic anamnesis . The results of the studies indicate that the leukocyte agglomeration reaction is a highly sensitive immunological indicator of hypersensitivity to antibiotics.

A pocket model for aluminum agglomeration in composite propellants

NASA Technical Reports Server (NTRS)

Cohen, N. S.

1981-01-01

This paper presents a model for the purpose of estimating the fraction of aluminum powder that will form agglomerates at the surface of deflagrating composite propellants. The basic idea is that the fraction agglomerated depends upon the amount of aluminum that melts within effective binder pocket volumes framed by oxidizer particles. The effective pocket depends upon the ability of ammonium perchlorate modals to encapsulate the aluminum and provide a local temperature sufficient to ignite the aluminum. Model results are discussed in the light of data showing effects of propellant formulation variables and pressure.

Use of Biomass Ash as a stabilization agent for expansive marly soils (SE Spain)

NASA Astrophysics Data System (ADS)

Ureña, C.; Azañón, J. M.; Caro, J. M.; Irigaray, C.; Corpas, F.; Ramirez, A.; Rivas, F.; Salazar, L. M.; Mochón, I.

2012-04-01

In recent years, several biomass power plants have been installed in Southeastern Spain to reuse olive oil industry residues. This energy production tries to reduce the high costs associated with fossil fuels, but without entering into direct competition to traditional food crops. The waste management in these biomass energy plants is still an issue since there are non-flammable materials which remains after incineration in the form of ashes. In Southeastern Spain there is also a great amount of clayey and marly soils whose volume is very sensitive to changes in climate conditions, making them unsuitable for civil engineering. We propose the use of biomass ash (both fly ash and bottom ash) as a stabilization agent for expansive soils in order to improve the efficiency of construction processes by using locally available materials. In this work biomass ashes from a biomass power plant in Southeastern Spain have been used to stabilize 6 samples of local marly soil. Those 6 samples of expansive soil were mixed with different dosages of biomass ash (2%, 4% and 7%) to create 18 specimens of treated soil, which were submitted to Proctor, Atterberg Limits, pH and Free Swell Index tests, following Spanish Standards UNE by AENOR. X-Ray Diffraction (XRD) tests by powder method were also carried out, using a diffractometer Philips X'Pert-MPD. The results obtained for the original untreated marly soil were: PI = 34.6; Free Swell = 12.5; pH = 8. By adding biomass ash the value of the plasticity index (PI) became slightly lower although it was not low enough as to obtain a non-plastic soil (PI under 25). However, there were dramatical decreases of free swell index (FSI) after the stabilization treatment: FSI < 8.18 (2% biomass); FSI < 6.15 (4% biomass); FSI < 4.18 (7% biomass); These results suggest that treated soil is quite less susceptible than the original soil to moisture changes. The pH of the mixes after adding biomass ash rose from 8 to 11±1 leading to an alkaline environment which, as reviewed literature points out, helps to the development of pozzolanic reactions and stabilization process. Finally, XRD tests indicated a sharp decrease in the intensity of reflection of the Smectite peak, suggesting a reduction in the amount of this expansive mineral in treated soils. This positive and durable effect may be related to cation exchange from Na+ to smaller cations or even the formation of mixed-layered clay minerals. A further research must be conducted to determine the pozzolanic properties of biomass ash (i.e., its suitability for concrete composites), the optimum dosages, etc. The further research is also necessary to better understand the mineralogy changes occurred within the crystalline structure. Nevertheless, these first results let us infer that biomass ash from power plants has a high capacity to enhance mechanical properties of expansive soils. Given the widespread use of biomass in industry today, the secondary use of biomass ash might improve the sustainability and efficiency of the biomass generation, incineration and waste management process.

Formation of Fe nanoparticles on water-washed coal fly ash for enhanced reduction of p-nitrophenol.

PubMed

Park, Jaehyeong; Bae, Sungjun

2018-07-01

The catalytic reduction of p-nitrophenol (p-NP) by coal fly ash (FA) washed with water was investigated in this study. A significant increase in pH (from 7.0 to 10.1) was observed in the suspension of raw fly ash (RFA), while water-washed fly ash (WFA) showed a relatively lower increase in pH (7.2), which was caused by the dissolution of Ca species during the water-washing process. Almost 33.4% of p-NP reduction was observed in the RFA suspension with NaBH 4 in 1 h, while the enhanced reduction of p-NP (87.2%) was observed in the WFA suspension. The catalytic reduction of p-NP was inhibited by addition of CaO and Ca(OH) 2 , indicating that higher amount of CaO dissolved from RFA resulted in the inhibition effect. Similar experiments using different oxides (i.e., Al 2 O 3 , SiO 2 , CaO and MgO) revealed no significant reduction of p-NP, which was comparable with Fe 2 O 3 (75.8%). Results from various surface analyses revealed that iron oxides on the surface of WFA can be reduced to elemental Fe nanoparticles, which can effectively reduce p-NP with NaBH 4 . No significant leaching of heavy metals such as Cr, Pb, and As was observed during the catalytic reduction of p-NP and in the suspension of WFA after reaction at pH 3, 5, 7, and 9 for 24 h, which can solve the toxic effect when the FA is used for environmental applications. We also observed a good reusability of WFA during the recycling test, indicating the potential use of WFA for the treatment of wastewater containing reductively degradable pollutants. Copyright © 2018 Elsevier Ltd. All rights reserved.

Enhancing heat capacity of colloidal suspension using nanoscale encapsulated phase-change materials for heat transfer.

PubMed

Hong, Yan; Ding, Shujiang; Wu, Wei; Hu, Jianjun; Voevodin, Andrey A; Gschwender, Lois; Snyder, Ed; Chow, Louis; Su, Ming

2010-06-01

This paper describes a new method to enhance the heat-transfer property of a single-phase liquid by adding encapsulated phase-change nanoparticles (nano-PCMs), which absorb thermal energy during solid-liquid phase changes. Silica-encapsulated indium nanoparticles and polymer-encapsulated paraffin (wax) nanoparticles have been made using colloid method, and suspended into poly-alpha-olefin (PAO) and water for potential high- and low-temperature applications, respectively. The shells prevent leakage and agglomeration of molten phase-change materials, and enhance the dielectric properties of indium nanoparticles. The heat-transfer coefficients of PAO containing indium nanoparticles (30% by mass) and water containing paraffin nanoparticles (10% by mass) are 1.6 and 1.75 times higher than those of corresponding single-phase fluids. The structural integrity of encapsulation allows repeated use of such nanoparticles for many cycles in high heat generating devices.

A model-based 'varimax' sampling strategy for a heterogeneous population.

PubMed

Akram, Nuzhat A; Farooqi, Shakeel R

2014-01-01

Sampling strategies are planned to enhance the homogeneity of a sample, hence to minimize confounding errors. A sampling strategy was developed to minimize the variation within population groups. Karachi, the largest urban agglomeration in Pakistan, was used as a model population. Blood groups ABO and Rh factor were determined for 3000 unrelated individuals selected through simple random sampling. Among them five population groups, namely Balochi, Muhajir, Pathan, Punjabi and Sindhi, based on paternal ethnicity were identified. An index was designed to measure the proportion of admixture at parental and grandparental levels. Population models based on index score were proposed. For validation, 175 individuals selected through stratified random sampling were genotyped for the three STR loci CSF1PO, TPOX and TH01. ANOVA showed significant differences across the population groups for blood groups and STR loci distribution. Gene diversity was higher across the sub-population model than in the agglomerated population. At parental level gene diversities are significantly higher across No admixture models than Admixture models. At grandparental level the difference was not significant. A sub-population model with no admixture at parental level was justified for sampling the heterogeneous population of Karachi.

Performance Improvement of V-Fe-Cr-Ti Solid State Hydrogen Storage Materials in Impure Hydrogen Gas.

PubMed

Ulmer, Ulrich; Oertel, Daria; Diemant, Thomas; Bonatto Minella, Christian; Bergfeldt, Thomas; Dittmeyer, Roland; Behm, R Jürgen; Fichtner, Maximilian

2018-01-17

Two approaches of engineering surface structures of V-Ti-based solid solution hydrogen storage alloys are presented, which enable improved tolerance toward gaseous oxygen (O 2 ) impurities in hydrogen (H 2 ) gas. Surface modification is achieved through engineering lanthanum (La)- or nickel (Ni)-rich surface layers with enhanced cyclic stability in an H 2 /O 2 mixture. The formation of a Ni-rich surface layer does not improve the cycling stability in H 2 /O 2 mixtures. Mischmetal (Mm, a mixture of La and Ce) agglomerates are observed within the bulk and surface of the alloy when small amounts of this material are added during arc melting synthesis. These agglomerates provide hydrogen-transparent diffusion pathways into the bulk of the V-Ti-Cr-Fe hydrogen storage alloy when the remaining oxidized surface is already nontransparent for hydrogen. Thus, the cycling stability of the alloy is improved in an O 2 -containing hydrogen environment as compared to the same alloy without addition of Mm. The obtained surface-engineered storage material still absorbs hydrogen after 20 cycles in a hydrogen-oxygen mixture, while the original material is already deactivated after 4 cycles.

EFFECTS OF SIZE FRACTIONATED AMBIENT PM SAMPLES ON INDUCTION OF PULMONARY ALLERGY IN MICE

EPA Science Inventory

There is increasing evidence that exposure to certain air pollutants including ozone and diesel exhaust can enhance allergic sensitization to allergens. Previous work from our laboratory has shown that exposure to residual oil fly ash or its associated transition metals can ...

Defense.gov Special Report: Travels With Carter

Science.gov Websites

. Story Carter Visits Silicon Valley Companies to Enhance DoD Technology Innovation Defense Secretary Ash innovation found in that part of the nation. Story Carter Seeks Tech-sector Partnerships During Two-day the highest-tech companies in one of the nation's innovation hotspots. Story Secretary's Silicon

The 2010 Eyja eruption evolution by using IR satellite sensors measurements: retrieval comparison and insights into explosive volcanic processes

NASA Astrophysics Data System (ADS)

Piscini, A.; Corradini, S.; Merucci, L.; Scollo, S.

2010-12-01

The 2010 April-May Eyja eruption caused an unprecedented disruption to economic, political and cultural activities in Europe and across the world. Because of the harming effects of fine ash particles on aircrafts, many European airports were in fact closed causing millions of passengers to be stranded, and with a worldwide airline industry loss estimated of about 2.5 billion Euros. Both security and economical issues require robust and affordable volcanic cloud retrievals that may be really improved through the intercomparison among different remote sensing instruments. In this work the Thermal InfraRed (TIR) measurements of different polar and geostationary satellites instruments as the Moderate Resolution Imaging Spectroradiometer (MODIS), the Advanced Very High Resolution Radiometer (AVHRR) and the Spin Enhanced Visible and Infrared Imager (SEVIRI), have been used to retrieve the volcanic ash and SO2 in the entire eruption period over Iceland. The ash retrievals (mass, AOD and effective radius) have been carried out by means of the split window BTD technique using the channels centered around 11 and 12 micron. The least square fit procedure is used for the SO2 retrieval by using the 7.3 and 8.7 micron channels. The simulated TOA radiance Look-Up Table (LUT) needed for both the ash and SO2 column abundance retrievals have been computed using the MODTRAN 4 Radiative Transfer Model. Further, the volcanic plume column altitude and ash density have been computed and compared, when available, with ground observations. The results coming from the retrieval of different IR sensors show a good agreement over the entire eruption period. The column height, the volcanic ash and the SO2 emission trend confirm the indentified different phases occurred during the Eyja eruption. We remark that the retrieved volcanic plume evolution can give important insights into eruptive dynamics during long-lived explosive activity.

Comparing grey water versus tap water and coal ash versus perlite on growth of two plant species on green roofs.

PubMed

Agra, Har'el; Solodar, Ariel; Bawab, Omar; Levy, Shay; Kadas, Gyongyver J; Blaustein, Leon; Greenbaum, Noam

2018-08-15

Green roofs provide important ecosystem services in urban areas. In Mediterranean and other semi-arid climate regions, most perennial plants on green roofs need to be irrigated during the dry season. However, the use of freshwater in such regions is scarce. Therefore, the possibility of using grey water should be examined. Coal ash, produced primarily from the burning of coal in power plants, constitutes an environmental contaminant that should be disposed. One option is to use ash as a growing substrate for plants. Here, we compare the effects of irrigating with grey- versus tap-water and using ash versus perlite as growing substrates in green roofs. The study was conducted in northern Israel in a Mediterranean climate. The design was full factorial with three factors: water-type (grey or tap-water)×substrate-type (coal ash vs perlite)×plant species (Phyla nodiflora, Convolvulus mauritanicus or no-plant). The development of plants and the quality of drainage water along the season, as well as quality of the used substrates were monitored. Both plant species developed well under all the experimental conditions with no effect of water type or substrate type. Under all treatments, both plant species enhanced electrical conductivity (EC) and chemical oxygen demand (COD) of the drainage water. In the summer, EC and COD reached levels that are unacceptable in water and are intended to be reused for irrigation. We conclude that irrigating with grey water and using coal ash as a growth substrate can both be implemented in green roofs. The drainage from tap water as well as from grey water can be further used for irrigating the roof, but for that, COD and EC levels must be lowered by adding a sufficient amount of tap water before reusing. Copyright © 2018 Elsevier B.V. All rights reserved.

The determination of optimum condition in water hyacinth drying process by mixed adsorption drying method and modified fly ash as an adsorbent

NASA Astrophysics Data System (ADS)

Saputra, Asep Handaya; Putri, Rizky Anggreini

2017-05-01

Water hyacinth is an aquatic weed that has a very fast growth which makes it becomes a problem to the ecosystem. On the other hand, water hyacinth has a high fiber content (up to 20% by weight) which makes it potential to become raw material for composites and textile industries. As an aquatic plant, water hyacinth has a high initial moisture content that reaches more than 90%. Meanwhile the moisture content of fiber as a raw material for composite and textile industry should not be more than 10% to maintain the good quality of the products. Mixed adsorption drying method is one of the innovative method that can replace conventional drying process. Fluidization method which has been commonly used in agricultural and pharmaceutical products drying, can be enhanced by combining it with the adsorption method as performed in this study. In mixed fluidization-adsorption drying method, fly ash as adsorbent and water hyacinth fiber were put together into the fluidization column where the drying air evaporate the moisture content in water hyacinth fiber. In addition, the adsorbent adsorb the moisture content in the drying air to make the moisture content of the drying air remain low. The drying process is performed in various temperature and composition of water hyacinth and adsorbent in order to obtain the optimum drying condition. In addition, the effect of fly ash pellet and fly ash powder to the drying process was also performed. The result shows that the higher temperature and the more amount of adsorbent results in the faster drying rate. Fly ash pellet shows a better adsorption since it has a smaller pore diameter and wider surface area. The optimum temperature obtained from this study is 60°C and the optimum ratio of water hyacinth and fly ash is 50:50.

Development and characterization of couscous-like product using bulgur flour as by-product.

PubMed

Yuksel, Ayse Nur; Öner, Mehmet Durdu; Bayram, Mustafa

2017-12-01

Couscous is produced traditionally by agglomeration of Triticum durum semolina with water. The aims of this study were: to produce couscous-like product by substitution of semolina with bulgur by-product (undersize bulgur); to find optimum quantity of bulgur flour and processing conditions. In order to determine the optimum processing parameters and recipes; 0, 25 and 50% of bulgur containing couscous-like samples were prepared. The color, yield, sensory properties, total phenol and flavonoid contents, bulk density, protein and ash content, texture properties were determined. Two different types of dryer e.g. packed bed and microwave were used. Optimum parameters were predicted as 50% of bulgur flour for packed bed (60 °C) and microwave (180 W) drying with 50% (w/w) of water according to yields, color (L*, a*, b*) values and sensory properties (color, odor, general appearance). For packed bed drying at 60 °C yields were 54.28 ± 3.78, 47.70 ± 1.73 and 52.57 ± 7.04% for 0, 25 and 50% bulgur flour containing samples, respectively. Lightness (L*) values of couscous-like samples were decreased with increasing the quantity of bulgur flour after both drying processes. Results of sensory analysis revealed that couscous-like bulgur were more preferable for consumers.

A comparison of dispersing media for various engineered carbon nanoparticles

PubMed Central

Buford, Mary C; Hamilton, Raymond F; Holian, Andrij

2007-01-01

Background With the increased manufacture and use of carbon nanoparticles (CNP) there has been increasing concern about the potential toxicity of fugitive CNP in the workplace and ambient environment. To address this matter a number of investigators have conducted in vitro and in vivo toxicity assessments. However, a variety of different approaches for suspension of these particles (culture media, Tween 80, dimethyl sulfoxide, phosphate-buffered saline, fetal calf serum, and others), and different sources of materials have generated potentially conflicting outcomes. The quality of the dispersion of nanoparticles is very dependent on the medium used to suspend them, and this then will most likely affect the biological outcomes. Results In this work, the distributions of different CNP (sources and types) have been characterized in various media. Furthermore, the outcome of instilling the different agglomerates, or size distributions, was examined in mouse lungs after one and seven days. Our results demonstrated that CNP suspended in serum produced particle suspensions with the fewest large agglomerates, and the most uniform distribution in mouse lungs. In addition, no apparent clearance of instilled CNP took place from lungs even after seven days. Conclusion This work demonstrates that CNP agglomerates are present in all dispersing vehicles to some degree. The vehicle that contains some protein, lipid or protein/lipid component disperses the CNP best, producing fewer large CNP agglomerates. In contrast, vehicles absent of lipid and protein produce the largest CNP agglomerates. The source of the CNP is also a factor in the degree of particle agglomeration within the same vehicle. PMID:17655771

Ion Pairing and Diffusion in Magnesium Electrolytes Based on Magnesium Borohydride.

PubMed

Samuel, Devon; Steinhauser, Carl; Smith, Jeffrey G; Kaufman, Aaron; Radin, Maxwell D; Naruse, Junichi; Hiramatsu, Hidehiko; Siegel, Donald J

2017-12-20

One obstacle to realizing a practical, rechargeable magnesium-ion battery is the development of efficient Mg electrolytes. Electrolytes based on simple Mg(BH 4 ) 2 salts suffer from poor salt solubility and/or low conductivity, presumably due to strong ion pairing. Understanding the molecular-scale processes occurring in these electrolytes would aid in overcoming these performance limitations. Toward this goal, the present study examines the solvation, agglomeration, and transport properties of a family of Mg electrolytes based on the Mg(BH 4 ) 2 salt using classical molecular dynamics. These properties were examined across five different solvents (tetrahydrofuran and the glymes G1-G4) and at four salt concentrations ranging from the dilute limit up to 0.4 M. Significant and irreversible salt agglomeration was observed in all solvents at all nondilute Mg(BH 4 ) 2 concentrations. The degree of clustering observed in these divalent Mg systems is much larger than that reported for electrolytes containing monovalent cations, such as Li. The salt agglomeration rate and diffusivity of Mg 2+ were both observed to correlate with solvent self-diffusivity: electrolytes using longer- (shorter-) chain solvents had the lowest (highest) Mg 2+ diffusivity and agglomeration rates. Incorporation of Mg 2+ into Mg 2+ -BH 4 - clusters significantly reduces the diffusivity of Mg 2+ by restricting displacements to localized motion within largely immobile agglomerates. Consequently, diffusion is increasingly impeded with increasing Mg(BH 4 ) 2 concentration. These data are consistent with the solubility limitations observed experimentally for Mg(BH 4 ) 2 -based electrolytes and highlight the need for strategies that minimize salt agglomeration in electrolytes containing divalent cations.

Comparing effectiveness of rhamnolipid biosurfactant with a quaternary ammonium salt surfactant for hydrate anti-agglomeration.

PubMed

York, J Dalton; Firoozabadi, Abbas

2008-01-24

Natural gas is projected to be the premium fuel of the 21st century because of availability, as well as economical and environmental considerations. Natural gas is coproduced with water from the subsurface forming gas hydrates. Hydrate formation may result in shutdown of onshore and offshore operations. Industry practice has been usage of alcohols--which have undesirable environmental impacts--to affect bulk-phase properties and inhibit hydrate formation. An alternative to alcohols is changing the surface properties through usage of polymers and surfactants, effective at 0.5-3 wt % of coproduced water. One group of low-dosage hydrate inhibitors (LDHI) are kinetic inhibitors, which affect nucleation rate and growth. A second group of LDHI are anti-agglomerants, which prevent agglomeration of small hydrate crystallites. Despite great potential, reported work on hydrate anti-agglomeration is very limited. In this paper, our focus is on the use of two vastly different surfactants as anti-agglomerants. We use a model oil, water, and tetrahydrofuran as a hydrate-forming species. We examine the effectiveness of a quaternary ammonium salt (i.e., quat). Visual observation measurements show that a small concentration of the quat (0.01%) can prevent agglomeration. However, a quat is not a green chemical and therefore may be undesirable. We show that a rhamnolipid biosurfactant can be effective to a concentration of 0.05 wt %. One difference between the two surfactants is the stability of the water-in-oil emulsions created. The biosurfactant forms a less stable emulsion, which makes it very desirable for hydrate application.

Impact of agglomeration state of nano- and submicron sized gold particles on pulmonary inflammation

PubMed Central

2010-01-01

Background Nanoparticle (NP) toxicity testing comes with many challenges. Characterization of the test substance is of crucial importance and in the case of NPs, agglomeration/aggregation state in physiological media needs to be considered. In this study, we have addressed the effect of agglomerated versus single particle suspensions of nano- and submicron sized gold on the inflammatory response in the lung. Rats were exposed to a single dose of 1.6 mg/kg body weight (bw) of spherical gold particles with geometric diameters of 50 nm or 250 nm diluted either by ultrapure water or by adding phosphate buffered saline (PBS). A single dose of 1.6 mg/kg bw DQ12 quartz was used as a positive control for pulmonary inflammation. Extensive characterization of the particle suspensions has been performed by determining the zetapotential, pH, gold concentration and particle size distribution. Primary particle size and particle purity has been verified using transmission electron microscopy (TEM) techniques. Pulmonary inflammation (total cell number, differential cell count and pro-inflammatory cytokines), cell damage (total protein and albumin) and cytotoxicity (alkaline phosphatase and lactate dehydrogenase) were determined in bronchoalveolar lavage fluid (BALF) and acute systemic effects in blood (total cell number, differential cell counts, fibrinogen and C-reactive protein) 3 and 24 hours post exposure. Uptake of gold particles in alveolar macrophages has been determined by TEM. Results Particles diluted in ultrapure water are well dispersed, while agglomerates are formed when diluting in PBS. The particle size of the 50 nm particles was confirmed, while the 250 nm particles appear to be 200 nm using tracking analysis and 210 nm using TEM. No major differences in pulmonary and systemic toxicity markers were observed after instillation of agglomerated versus single gold particles of different sizes. Both agglomerated as well as single nanoparticles were taken up by macrophages. Conclusion Primary particle size, gold concentration and particle purity are important features to check, since these characteristics may deviate from the manufacturer's description. Suspensions of well dispersed 50 nm and 250 nm particles as well as their agglomerates produced very mild pulmonary inflammation at the same mass based dose. We conclude that single 50 nm gold particles do not pose a greater acute hazard than their agglomerates or slightly larger gold particles when using pulmonary inflammation as a marker for toxicity. PMID:21126342

Comparative Physicochemical Evaluation of Kharekhasak (Tribulus terrestris Linn.) Before and After Mudabbar Process

PubMed Central

Tauheed, Abdullah; Hamiduddin; Khanam, Salma; Ali, Mohd Akhtar; Zaigham, Mohammad

2017-01-01

Background and Objectives: Mudabbar/Tadbeere advia is referred to the processes performed on the drugs to detoxify, purify, and enhance therapeutic action and to reduce its doses before making the formulations in Unani medicine. It improves quality of drugs either by optimizing its desirable characteristics or minimizing the undesirable ones; it makes drug effective, safe, and specific. There is a need of comparative evaluation to understand its significance. Tadbeer of Kharekhasak (KK) khurd (Tribulus terrestris Linn. fruit) is described by Rabban Al-Tabari in Firdausul Hikmat, Akbar Arzani in Qarabadeene Qadri, etc., during the compounding of aphrodisiac formulations. Mudabbar Kharekhasak (MKK) used in Safoofe Kharekhasak mentioned in Al-Qarabadeene was evaluated in this work. Methods: Mudabbar/Tadbeer process was carried out by blending fresh KK. Juice with powdered dry KK and drying it under the sun. Juice used for process is thrice the weight of dry KK powder. The KK before and after the process was evaluated using physicochemical tests: powder characterization, extractive value, alcohol and water soluble matter, ash value, loss on drying (LOD) at 105°C, pH, high-performance thin layer chromatography (HPTLC) fingerprinting, and diosgenin content. Results: Powder characterizations were set in. Increase in successive and nonsuccessive extractive values in various solvents, water/alcohol-soluble content, total ash, acid-insoluble ash, water-soluble ash, and sulfated ash of MKK was noted in comparison with KK. Decrease in LOD at 105°C and pH of MKK powder was observed. HPTLC fingerprinting data were developed for the identification and evaluation. Quantification of diosgenin content increased to 432.1 g/g in MKK as compared to 144.5 g/g in KK, suggesting significant increase in saponin content. Conclusion: Data obtained clearly indicated changes in MKK validating the classical Mudabbar process, probably to enhance/modify the action of drug. Standards for crude and MKK were established for future reference. SUMMARY Mudabbar process on Tribulus terrestris Linn (KK) havebeen validated.Physicochemical data for Mudabbar and non mudabbar Kharekhasak (KK) powder have been set in.Diosgenin content was increased significantly in mudabbar KK. Abbreviations Used: KK: Kharekhasak, TT: Tribulus terrestris, MKK: mudabbar Kharekhasak, SK: Safoofe Kharekhasak, LOD: loss of weight on drying, HPTLC: High performance thin layer chromatography, BSS: British standard sieve, μl: microliter, SEM: Standard error of mean, nm: nanometer, g: gram. PMID:29263633

Comparative Physicochemical Evaluation of Kharekhasak (Tribulus terrestris Linn.) Before and After Mudabbar Process.

PubMed

Tauheed, Abdullah; Hamiduddin; Khanam, Salma; Ali, Mohd Akhtar; Zaigham, Mohammad

2017-01-01

Mudabbar/ Tadbeere advia is referred to the processes performed on the drugs to detoxify, purify, and enhance therapeutic action and to reduce its doses before making the formulations in Unani medicine. It improves quality of drugs either by optimizing its desirable characteristics or minimizing the undesirable ones; it makes drug effective, safe, and specific. There is a need of comparative evaluation to understand its significance. Tadbeer of Kharekhasak (KK) khurd ( Tribulus terrestris Linn. fruit) is described by Rabban Al-Tabari in Firdausul Hikmat, Akbar Arzani in Qarabadeene Qadri, etc., during the compounding of aphrodisiac formulations. Mudabbar Kharekhasak (MKK) used in Safoofe Kharekhasak mentioned in Al-Qarabadeene was evaluated in this work. Mudabbar/Tadbeer process was carried out by blending fresh KK. Juice with powdered dry KK and drying it under the sun. Juice used for process is thrice the weight of dry KK powder. The KK before and after the process was evaluated using physicochemical tests: powder characterization, extractive value, alcohol and water soluble matter, ash value, loss on drying (LOD) at 105°C, pH, high-performance thin layer chromatography (HPTLC) fingerprinting, and diosgenin content. Powder characterizations were set in. Increase in successive and nonsuccessive extractive values in various solvents, water/alcohol-soluble content, total ash, acid-insoluble ash, water-soluble ash, and sulfated ash of MKK was noted in comparison with KK. Decrease in LOD at 105°C and pH of MKK powder was observed. HPTLC fingerprinting data were developed for the identification and evaluation. Quantification of diosgenin content increased to 432.1 g/g in MKK as compared to 144.5 g/g in KK, suggesting significant increase in saponin content. Data obtained clearly indicated changes in MKK validating the classical Mudabbar process, probably to enhance/modify the action of drug. Standards for crude and MKK were established for future reference. Mudabbar process on Tribulus terrestris Linn (KK) havebeen validated.Physicochemical data for Mudabbar and non mudabbar Kharekhasak (KK) powder have been set in.Diosgenin content was increased significantly in mudabbar KK. Abbreviations Used: KK: Kharekhasak, TT: Tribulus terrestris , MKK: mudabbar Kharekhasak, SK: Safoofe Kharekhasak , LOD: loss of weight on drying, HPTLC: High performance thin layer chromatography, BSS: British standard sieve, μl: microliter, SEM: Standard error of mean, nm: nanometer, g: gram.

Investigation of effects of prolonged inhalation of nickel-enriched fly ash in Syrian Golden hamsters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wehner, A.P.

1981-01-01

Groups of 102 Male Syrian Golden hamsters were chronically exposed to approx. 70 micrograms/l respirable Nickel Enriched Fly Ash aerosol (high NEFA group), approx. 17 micrograms/l (low NEFA group), or approx. 70 micrograms/l FA 6 hrs/day, 5 days/week for 4, 8, 12, 16, and 20 months. Identical control groups received sham exposures. The NEFA particles of respirable size contained approximately 6% nickel, compared to about 0.3% for FA. Exposure to NEFA had no significant effect on the apparent well being, body weight and life span of the animals although heavy deposits of NEFA in the lungs were found. The lungmore » weights and mean lung volumes of the high NEFA and FA exposed animals were significantly higher and larger, respectively, than for the low NEFA and control groups. There was a 100% incidence of dust deposition (anthracosis) and significantly higher incidence plus severity of interstitial reaction and bronchiolization in the dust-exposed groups than the controls. The severity of lung reactions was significantly lower in the low NEFA group than the high NEFA and FA groups. The results of this study conclude that the addition of nickel to fly ash under these conditions did not significantly (P< 0.05) enhance the pathogenicity (including carcinogenicity) of fly ash in this animal model.« less

Surface-coated fly ash used as filler in biodegradable poly(vinyl alcohol) composite films: Part 1—The modification process

NASA Astrophysics Data System (ADS)

Nath, D. C. D.; Bandyopadhyay, S.; Gupta, S.; Yu, A.; Blackburn, D.; White, C.

2010-02-01

The surfaces of fly ash (FA) particles were modified by surfactant, sodium lauryl sulphate (SLS) and used in fabrication of composite films with polyvinyl alcohol (PVA). Both unmodified fly ash (FA) and modified fly ash (SLS-FA) samples were examined using a range of analytical tools including X-ray fluorescence spectroscopy (XRF), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The distribution patterns of SLS-FA particles were shifted to the higher regions compared to FA by adding 1.2-4.2 μm in the ranges between 2 and 25 μm, whereas the modification process reduced the size of the particles over 25 μm due to grinding during the activation process. The increased 1.2-4.2 μm in average can be considered the thickness of the surfactant on the SLS-FA surface. On the oxides based chemical analysis by XRF, the compositions were almost unchanged. SEM and TEM were visualised the irregular sizes morphology mostly spherical of the particles, although it is impossible to capture the images of exactly same particles in modified and unmodified forms. The composite films reinforced with SLS-FA showed 33% higher strength than those of FA filled films. The enhancement of tensile strength attributed from the level of physical bonding between SLS-FA and PVA surfaces.

Novel dry-desulfurization process using Ca(OH)2/fly ash sorbent in a circulating fluidized bed.

PubMed

Matsushima, Norihiko; Li, Yan; Nishioka, Masateru; Sadakata, Masayoshi; Qi, Haiying; Xu, Xuchang

2004-12-15

A dry-desulfurization process using Ca(OH)2/fly ash sorbent and a circulating fluidized bed (CFB) was developed. Its aim was to achieve high SO2 removal efficiency without humidification and production of CaSO4 as the main byproduct. The CaSO4 produced could be used to treat alkalized soil. An 83% SO2 removal rate was demonstrated, and a byproduct with a high CaSO4 content was produced through baghouse ash. These results indicated that this process could remove SO2 in flue gas with a high efficiency under dry conditions and simultaneously produce soil amendment. It was shown that NO and NO2 enhanced the SO2 removal rate markedly and that NO2 increased the amount of CaSO4 in the final product more than NO. These results confirmed that the significant effects of NO and NO2 on the SO2 removal rate were due to chain reactions that occurred under favorable conditions. The amount of baghouse ash produced increased as the reaction progressed, indicating that discharge of unreacted Ca(OH)2 from the reactor was suppressed. Hence, unreacted Ca(OH)2 had a long residence time in the CFB, resulting in a high SO2 removal rate. It was also found that 350 degrees C is the optimum reaction temperature for dry desulfurization in the range tested (320-380 degrees C).

Valorization of lignite combustion residues and ferroalumina in the production of aggregates.

PubMed

Anagnostopoulos, I M; Stivanakis, V E; Angelopoulos, G N; Papamantellos, D C

2010-02-15

The present research study investigates the synergy of industrial solid by-products from lignite combustion (fly ash and bottom ash) and aluminum production (ferroalumina) in the production of lightweight aggregates (LWA). The process consists of two stages, pelletization and sintering. Bottom ash (BA) is used as the principal raw material in mixtures while ferroalumina (FAL) is added in lower percentages (5-30 wt%). BA carbon content is used as the fuel of sintering process in high temperatures, around 1250 degrees C, and gas generation is responsible for porous structure formation. Physical properties such as porosity, water absorption and bulk density, of sintering products are measured. Increase of FAL percentage in sintering mixtures results in decrease of porosity from 61% to 35% and of water absorption from 61% to 21% and in increase of bulk density from 1.02 g/cm(3) to 1.80 g/cm(3) of the produced aggregates. Aggregates produced by FAL addition up to 20 wt% are characterized as LWA. Aggregates formed are used in the production of concrete specimens. Compressive strength of concrete increases by increasing FAL addition in aggregates from 5 wt% to 15 wt% (highest strength value), while decrease by increasing FAL addition from 20 wt% to 30 wt%. FAL addition in lignite ashes sintering mixtures (up to 15 wt%) is considered as an important parameter for enhancing aggregates strength.

Mixing of nanosize particles by magnetically assisted impaction techniques

NASA Astrophysics Data System (ADS)

Scicolone, James V.

Nanoparticles and nanocomposites offer unique properties that arise from their small size, large surface area, and the interactions of phases at their interfaces, and are attractive for their potential to improve performance of drugs, biomaterials, catalysts and other high-value-added materials. However, a major problem in utilizing nanoparticles is that they often lose their high surface area due to grain growth. Creating nanostructured composites where two or more nanosized constituents are intimately mixed can prevent this loss in surface area, but in order to obtain homogeneous mixing, de-agglomeration of the individual nanoparticle constituents is necessary. Due to high surface area, nano-particles form very large, fractal agglomerates. The structure of these agglomerates can have a large agglomerate composed of sub-agglomerates (SA), which itself consists of primary agglomerates (PA), that contain chain or net like nano-particle structures; typically sub-micron size. Thus the final agglomerate has a hierarchical, fractal structure, and depending upon the forces applied, it could break down to a certain size scale. The agglomerates can be fairly porous and fragile or they could be quite dense, based on primary particle size and its surface energy. Thus depending upon the agglomerate strength at different length scales, one could achieve deagglomeration and subsequent mixing at varying length scale. A better understanding of this can have a major impact on the field of nano-structured materials; thus the long term objective of this project is to gain fundamental understanding of deagglomeration and mixing of nano-agglomerates. Dry mixing is in general not effective in achieving desired mixing at nanoscale, whereas wet mixing suffers from different disadvantages like nanomaterial of interest should be insoluble, has to wet the liquid, and involves additional steps of filtration and drying. This research examines the use of environmentally friendly a novel approach based on use of small magnetic particles as mixing media is introduced that achieves a high-degree of mixing at scales of about a micron. The method is tested for binary mixture of alumina/silica and silica/titania. Various parameters such as processing time, size of the magnets, and magnetic particle to powder mixed ratio are considered. Experiments are carried out in batch containers in liquid and dry mediums, as well as a fluidized bed set-up. Homogeneity of Mixing (HoM), defined as the compliment of the Intensity of Segregation, was evaluated at the micron scale through field-emission scanning electron microscopy (FESEM) and the energy dispersive x-ray spectroscopy (EDS). Secondary electron images, along with elemental mappings, were used to visualize the change in agglomerate sizes. Compositional percent data of each element were obtained through an EDS spatial distribution point analysis and used to obtain quantitative analysis on the homogeneity of the mixture. The effect of magnet impaction on mixing quality was examined on the HoM of binary mixtures. The research shows that HoM improved with magnetically assisted impaction mixing techniques indicating that the HoM depends on the product of processing time with the number of magnets. In a fluidized bed set-up, MAIM not only improved dispersion, but it was also found that the magnetic particles served to break down the larger agglomerates, to reduce the minimum fluidization velocity, to delay the onset of bubbling, and to convert the fluidization behavior of ABF powder to APF. Thus MAIM techniques may be used to achieve mixing of nanopowders at a desired HoM through adjusting the number of magnets and processing time; and its inherent advantages are its simplicity, an environmentally benign operation, and reduced cost as compared with wet mixing techniques.

Enhancement of Ce/Cr Codopant Solubility and Chemical Homogeneity in TiO2 Nanoparticles through Sol-Gel versus Pechini Syntheses.

PubMed

Chen, Wen-Fan; Mofarah, Sajjad S; Hanaor, Dorian Amir Henry; Koshy, Pramod; Chen, Hsin-Kai; Jiang, Yue; Sorrell, Charles Christopher

2018-06-18

Ce/Cr codoped TiO 2 nanoparticles were synthesized using sol-gel and Pechini methods with heat treatment at 400 °C for 4 h. A conventional sol-gel process produced well-crystallized anatase, while Pechini synthesis yielded less-ordered mixed-phase anatase + rutile; this suggests that the latter method enhances Ce solubility and increases chemical homogeneity but destabilizes the TiO 2 lattice. Greater structural disruption from the decomposition of the Pechini precursor formed more open agglomerated morphologies, while the lower levels of structural disruption from pyrolysis of the dried sol-gel precursor resulted in denser agglomerates of lower surface areas. Codoping and associated destabilization of the lattice reduced the binding energies in both powders. Cr 4+ formation in sol-gel powders and Cr 6+ formation in Pechini powders suggest that these valence changes derive from synergistic electron exchange from intervalence and/or multivalence charge transfer. Since Ce is too large to allow either substitutional or interstitial solid solubility, the concept of integrated solubility is introduced, in which the Ti site and an adjacent interstice are occupied by the large Ce ion. The photocatalytic performance data show that codoping was detrimental owing to the effects of reduced crystallinity from lattice destabilization and surface area. Two regimes of mechanistic behavior are seen, which are attributed to the unsaturated solid solutions at lower codopant levels and supersaturated solid solutions at higher levels. The present work demonstrates that the Pechini method offers a processing technique that is superior to sol-gel because the former facilitates solid solubility and consequent chemical homogeneity.

Maximization of organic acids production by Aspergillus niger in a bubble column bioreactor for V and Ni recovery enhancement from power plant residual ash in spent-medium bioleaching experiments.

PubMed

Rasoulnia, P; Mousavi, S M

2016-09-01

Spent-medium bioleaching of V and Ni from a power plant residual ash (PPR ash) was conducted using organic acids produced by Aspergillus niger. The production of organic acids in a bubble column bioreactor was optimized through selecting three most influencing factors. Under optimum condition of aeration rate of 762.5(ml/min), sucrose concentration of 101.9(g/l) and inoculum size of 40(ml/l), respectively 17,185, 4539, 1042 and 502(ppm) of oxalic, gluconic, citric and malic acids were produced. Leaching experiments were carried out using biogenic produced organic acids under leaching environment temperature of 60°C and rotary shaking speed of 135rpm, with various pulp densities of 1, 2, 3, 5, 7 and 9(%w/v). The results showed that biogenic produced organic acids leached V much more efficiently than Ni so that even at high pulp density of 9(%w/v), 83% of V was recovered while Ni recovery yield was 30%. Copyright © 2016 Elsevier Ltd. All rights reserved.

A pilot and field investigation on mobility of PCDDs/PCDFs in landfill site with municipal solid waste incineration residue.

PubMed

Osako, Masahiro; Kim, Yong-Jin; Lee, Dong-Hoon

2002-09-01

A field investigation by boring was carried out in a landfill site primarily with municipal solid waste incineration residue. From the collected core samples, vertical profiles of homologous content of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs) in the landfill layer were traced and the behavior of PCDDs/PCDFs was examined. In addition, a pilot-scale study was conducted on the PCDDs/PCDFs leached from incineration fly ash and the treated one using large landfill simulation columns (lysimeters) and the leaching behavior of PCDDs/PCDFs was examined. As a result, it was found that the coexistence of dissolved coloring constituents (DCCs), which might be composed of constituents like dissolved humic matters having strong affinity for hydrophobic organic pollutants, could enhance the leachability of PCDDs/PCDFs, thus contributing to the vertical movement and leaching behavior of PCDDs/PCDFs in the landfill layers of the incineration residue. Moreover, it is highly probable that DCCs derive from the unburned carbon in the bottom ash mixed and buried with the fly ash containing a high content of PCDDs/PCDFs.

Conversion of coal-fired bottom ash to fuel and construction materials.

PubMed

Koca, Huseyin; Aksoy, Derya Oz; Ucar, Reyhan; Koca, Sabiha

2017-07-01

In this study, solid wastes taken from Seyitomer coal-fired power plant bottom ashes were subjected to experimental research to obtain a carbon-rich fraction. The possible recycling opportunities of remaining inorganic fraction in the cement and concrete industry was also investigated. Flotation technique was used to separate unburned carbon from inorganic bottom ashes. Collector type, collector, dispersant and frother amounts, and pulp density are the most important variables in the flotation technique. A number of flotation collectors were tested in the experiments including new era flotation reactives. Optimum collector, dispersant and frother dosages as well as optimum pulp density were also determined. After experimental work, an inorganic fraction was obtained, which included 5.41% unburned carbon with 81.56% weight yield. These properties meets the industrial specifications for the cement and concrete industry. The carbon content of the concentrate fraction, obtained in the same experiment, was enhanced to 49.82%. This fraction accounts for 18.44% of the total amount and can be mixed to the power plant fuel. Therefore total amount of the solid waste can possibly be recycled according to experimental results.

Enhancing the use of waste activated sludge as bio-fuel through selectively reducing its heavy metal content.

PubMed

Dewil, Raf; Baeyens, Jan; Appels, Lise

2007-06-18

Power plant or cement kiln co-incineration are important disposal routes for the large amounts of waste activated sludge (WAS) which are generated annually. The presence of significant amounts of heavy metals in the sludge however poses serious problems since they are partly emitted with the flue gases (and collected in the flue gas dedusting) and partly incorporated in the ashes of the incinerator: in both cases, the disposal or reuse of the fly ash and bottom ashes can be jeopardized since subsequent leaching in landfill disposal can occur, or their "pozzolanic" incorporation in cement cannot be applied. The present paper studies some physicochemical methods for reducing the heavy metal content of WAS. The used techniques include acid and alkaline thermal hydrolysis and Fenton's peroxidation. By degrading the extracellular polymeric substances, binding sites for a large amount of heavy metals, the latter are released into the sludge water. The behaviour of several heavy metals (Cd, Cr, Cu, Hg, Pb, Ni, Zn) was assessed in laboratory tests. Results of these show a significant reduction of most heavy metals.

Strength characteristics of light weight concrete blocks using mineral admixtures

NASA Astrophysics Data System (ADS)

Bhuvaneshwari, P.; Priyadharshini, U.; Gurucharan, S.; Mithunram, B.

2017-07-01

This paper presents an experimental study to investigate the characteristics of light weight concrete blocks. Cement was partially replaced with mineral admixtures like Fly ash (FA), limestone powder waste (LPW), Rice husk ash (RHA), sugarcane fiber waste (SCW) and Chrysopogonzizanioides (CZ). The maximum replacement level achieved was 25% by weight of cement and sand. Total of 56 cubes (150 mm x 150 mm x150 mm) and 18 cylinders (100mmφ and 50mm depth) were cast. The specimens being (FA, RHA, SCW, LPW, CZ, (FA-RHA), (FA-LPW), (FA-CZ), (LPW-CZ), (FA-SCW), (RHA-SCW)).Among the different combination, FA,FA-SCW,CZ,FA-CZ showed enhanced strength and durability, apart from achieving less density.

The structure of hydrophobic gas diffusion electrodes.

NASA Technical Reports Server (NTRS)

Giner, J.

1972-01-01

The 'flooded agglomerate' model of the Teflon-bonded gas diffusion electrode is discussed. A mathematical treatment of the 'flooded agglomerate' model is given; it can be used to predict the performance of the electrode as a function of measurable physical parameters.

Growth and form of planetary seedlings: results from a microgravity aggregation experiment.

PubMed

Blum, J; Wurm, G; Kempf, S; Poppe, T; Klahr, H; Kozasa, T; Rott, M; Henning, T; Dorschner, J; Schräpler, R; Keller, H U; Markiewicz, W J; Mann, I; Gustafson, B A; Giovane, F; Neuhaus, D; Fechtig, H; Grün, E; Feuerbacher, B; Kochan, H; Ratke, L; El Goresy, A; Morfill, G; Weidenschilling, S J; Schwehm, G; Metzler, K; Ip, W H

2000-09-18

The outcome of the first stage of planetary formation, which is characterized by ballistic agglomeration of preplanetary dust grains due to Brownian motion in the free molecular flow regime of the solar nebula, is still somewhat speculative. We performed a microgravity experiment flown onboard the space shuttle in which we simulated, for the first time, the onset of free preplanetary dust accumulation and revealed the structures and growth rates of the first dust agglomerates in the young solar system. We find that a thermally aggregating swarm of dust particles evolves very rapidly and forms unexpected open-structured agglomerates.

Quantitative characterization of nanoparticle agglomeration within biological media

NASA Astrophysics Data System (ADS)

Hondow, Nicole; Brydson, Rik; Wang, Peiyi; Holton, Mark D.; Brown, M. Rowan; Rees, Paul; Summers, Huw D.; Brown, Andy

2012-07-01

Quantitative analysis of nanoparticle dispersion state within biological media is essential to understanding cellular uptake and the roles of diffusion, sedimentation, and endocytosis in determining nanoparticle dose. The dispersion of polymer-coated CdTe/ZnS quantum dots in water and cell growth medium with and without fetal bovine serum was analyzed by transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. Characterization by TEM of samples prepared by plunge freezing the blotted solutions into liquid ethane was sensitive to the dispersion state of the quantum dots and enabled measurement of agglomerate size distributions even in the presence of serum proteins where DLS failed. In addition, TEM showed a reduced packing fraction of quantum dots per agglomerate when dispersed in biological media and serum compared to just water, highlighting the effect of interactions between the media, serum proteins, and the quantum dots. The identification of a heterogeneous distribution of quantum dots and quantum dot agglomerates in cell growth medium and serum by TEM will enable correlation with the previously reported optical metrology of in vitro cellular uptake of this quantum dot dispersion. In this paper, we present a comparative study of TEM and DLS and show that plunge-freeze TEM provides a robust assessment of nanoparticle agglomeration state.

Examining the effects of urban agglomeration polders on flood events in Qinhuai River basin, China with HEC-HMS model.

PubMed

Gao, Yuqin; Yuan, Yu; Wang, Huaizhi; Schmidt, Arthur R; Wang, Kexuan; Ye, Liu

2017-05-01

The urban agglomeration polders type of flood control pattern is a general flood control pattern in the eastern plain area and some of the secondary river basins in China. A HEC-HMS model of Qinhuai River basin based on the flood control pattern was established for simulating basin runoff, examining the impact of urban agglomeration polders on flood events, and estimating the effects of urbanization on hydrological processes of the urban agglomeration polders in Qinhuai River basin. The results indicate that the urban agglomeration polders could increase the peak flow and flood volume. The smaller the scale of the flood, the more significant the influence of the polder was to the flood volume. The distribution of the city circle polder has no obvious impact on the flood volume, but has effect on the peak flow. The closer the polder is to basin output, the smaller the influence it has on peak flows. As the level of urbanization gradually improving of city circle polder, flood volumes and peak flows gradually increase compared to those with the current level of urbanization (the impervious rate was 20%). The potential change in flood volume and peak flow with increasing impervious rate shows a linear relationship.

Comparison of the agglomeration behavior of thin metallic films on SiO2

NASA Astrophysics Data System (ADS)

Gadkari, P. R.; Warren, A. P.; Todi, R. M.; Petrova, R. V.; Coffey, K. R.

2005-07-01

The stability of continuous metallic thin films on insulating oxide surfaces is of interest to applications such as semiconductor interconnections and gate engineering. In this work, we report the study of the formation of voids and agglomeration of initially continuous Cu, Au, Ru and Pt thin films deposited on amorphous thermally grown SiO2 surfaces. Polycrystalline thin films having thicknesses in the range of 10-100 nm were ultrahigh vacuum sputter deposited on thermally grown SiO2 surfaces. The films were annealed at temperatures in the range of 150-800 °C in argon and argon+3% hydrogen gases. Scanning electron microscopy was used to investigate the agglomeration behavior, and transmission electron microscopy was used to characterize the microstructure of the as-deposited and annealed films. The agglomeration sequence in all of the films is found to follow a two step process of void nucleation and void growth. However, void growth in Au and Pt thin films is different from Cu and Ru thin films. Residual stress and adhesion were observed to play an important part in deciding the mode of void growth in Au and Pt thin films. Last, it is also observed that the tendency for agglomeration can be reduced by encapsulating the metal film with an oxide overlayer.

A complex network approach for nanoparticle agglomeration analysis in nanoscale images

NASA Astrophysics Data System (ADS)

Machado, Bruno Brandoli; Scabini, Leonardo Felipe; Margarido Orue, Jonatan Patrick; de Arruda, Mauro Santos; Goncalves, Diogo Nunes; Goncalves, Wesley Nunes; Moreira, Raphaell; Rodrigues-Jr, Jose F.

2017-02-01

Complex networks have been widely used in science and technology because of their ability to represent several systems. One of these systems is found in Biochemistry, in which the synthesis of new nanoparticles is a hot topic. However, the interpretation of experimental results in the search of new nanoparticles poses several challenges. This is due to the characteristics of nanoparticle images and due to their multiple intricate properties; one property of recurrent interest is the agglomeration of particles. Addressing this issue, this paper introduces an approach that uses complex networks to detect and describe nanoparticle agglomerates so to foster easier and more insightful analyses. In this approach, each detected particle in an image corresponds to a vertice and the distances between the particles define a criterion for creating edges. Edges are created if the distance is smaller than a radius of interest. Once this network is set, we calculate several discrete measures able to reveal the most outstanding agglomerates in a nanoparticle image. Experimental results using images of scanning tunneling microscopy (STM) of gold nanoparticles demonstrated the effectiveness of the proposed approach over several samples, as reflected by the separability between particles in three usual settings. The results also demonstrated efficacy for both convex and non-convex agglomerates.

Direct numerical simulations of agglomeration of circular colloidal particles in two-dimensional shear flow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Young Joon, E-mail: yjchoi@uvic.ca; Djilali, Ned, E-mail: ndjilali@uvic.ca

2016-01-15

Colloidal agglomeration of nanoparticles in shear flow is investigated by solving the fluid-particle and particle-particle interactions in a 2D system. We use an extended finite element method in which the dynamics of the particles is solved in a fully coupled manner with the flow, allowing an accurate description of the fluid-particle interfaces without the need of boundary-fitted meshes or of empirical correlations to account for the hydrodynamic interactions between the particles. Adaptive local mesh refinement using a grid deformation method is incorporated with the fluid-structure interaction algorithm, and the particle-particle interaction at the microscopic level is modeled using the Lennard-Jonesmore » potential. Motivated by the process used in fabricating fuel cell catalysts from a colloidal ink, the model is applied to investigate agglomeration of colloidal particles under external shear flow in a sliding bi-periodic Lees-Edwards frame with varying shear rates and particle fraction ratios. Both external shear and particle fraction are found to have a crucial impact on the structure formation of colloidal particles in a suspension. Segregation intensity and graph theory are used to analyze the underlying agglomeration patterns and structures, and three agglomeration regimes are identified.« less

In-plant testing of a novel coal cleaning circuit using advanced technologies. Final technical report, September 1, 1995--August 31, 1996

DOE Office of Scientific and Technical Information (OSTI.GOV)

Honaker, R.Q.; Reed, S.; Mohanty, M.K.

1997-05-01

A circuit comprised of advanced fine coal cleaning technologies was evaluated in an operating preparation plant to determine circuit performance and to compare the performance with current technologies used to treat -16 mesh fine coal. The circuit integrated a Floatex hydrosizer, a Falcon enhanced gravity concentrator and a Jameson flotation cell. A Packed-Column was used to provide additional reductions in the pyritic sulfur and ash contents by treatment of the Floatex-Falcon-Jameson circuit product. For a low sulfur Illinois No. 5 coal, the pyritic sulfur content was reduced from 0.67% to 0.34% at a combustible recovery of 93.2%. The ash contentmore » was decreased from 27.6% to 5.84%, which equates to an organic efficiency of 95% according to gravity-based washability data. The separation performance achieved on a high sulfur Illinois No. 5 coal resulted in the rejection of 72.7% of the pyritic sulfur and 82.3% of the ash-forming material at a recovery of 8 1 %. Subsequent pulverization of the cleaned product and retreatment in a Falcon concentrator and Packed-Column resulted in overall circuit ash and pyritic sulfur rejections of 89% and 93%, respectively, which yielded a pyritic sulfur content reduction from 2.43% to 0.30%. This separation reduced the sulfur dioxide emission rating of an Illinois No. 5 coal from 6.21 to 1.75 lbs SO{sub 2}/MBTU, which is Phase I compliance coal. A comparison of the results obtained from the Floatex-Falcon-Jameson circuit with those of the existing circuit revealed that the novel fine coal circuit provides 10% to 20% improvement in mass yield to the concentrate while rejecting greater amounts of ash and pyritic sulfur.« less

Multi-sensor satellite monitoring of ash and SO2 volcanic plume in support to aviation control

NASA Astrophysics Data System (ADS)

Brenot, Hugues; Theys, Nicolas; Clarisse, Lieven; van Geffen, Jos; van Gent, Jeroen; Van Roozendael, Michel; van der A, Ronald; Hurtmans, Daniel; Coheur, Pierre-Francois; Clerbaux, Cathy; Valks, Pieter; Hedelt, Pascal; Prata, Fred; Rasson, Olivier; Sievers, Klaus; Zehner, Claus

2014-05-01

The 'Support to Aviation Control Service' (SACS; http://sacs.aeronomie.be) is an ESA-funded project hosted by the Belgian Institute for Space Aeronomy since 2007. The service provides near real-time (NRT) global volcanic ash and SO2 observations, as well as notifications in case of volcanic eruptions (success rate >95% for ash and SO2). SACS is based on the combined use of UV-visible (OMI, GOME-2 MetOp-A, GOME-2 MetOp-B) and infrared (AIRS, IASI MetOp-A, IASI MetOp-B) satellite instruments. The SACS service is primarily designed to support the Volcanic Ash Advisory Centers (VAACs) in their mandate to gather information on volcanic clouds and give advice to airline and air traffic control organisations. SACS also serves other users that subscribe to the service, in particular local volcano observatories, research scientists and airliner pilots. When a volcanic eruption is detected, SACS issues a warning that takes the form of a notification sent by e-mail to users. The SACS notification points to a dedicated web page where all relevant information is available and can be visualised with user-friendly tools. Information about the volcanic plume height from GOME-2 (MetOp-A and MetOp-B) are also available. The strength of a multi-sensor approach relies in the use of satellite data with different overpasses times, minimising the time-lag for detection and enhancing the reliability of such alerts. This presentation will give an overview of the SACS service, and of the different techniques used to detect volcanic plumes (ash, SO2 and plume height). It will also highlight the strengths and limitations of the service and measurements, and some perspectives.

Studies on mycorrhizal inoculation on dry matter yield and root colonization of some medicinal plants grown in stress and forest soils.

PubMed

Chandra, K K; Kumar, Neeraj; Chand, Gireesh

2010-11-01

Five medicinal plants viz. Abelmoschatus moschatus Linn., Clitoria tematea L., Plumbagozeylanica L., Psorolea corylifolia L. and Withania sominifera L. were grown in a polypot experiment in five soils representing coal mine soil, coppermine soil, fly ash, skeletal soil and forest soil with and without mycorrhizal inoculations in a completely randomized block design. Dry matter yield and mycorrhizal root colonization of plants varied both in uninoculated and inoculated conditions. The forest soil rendered highest dry matter due to higher yield of A. moschatus, P. zeylanica and P corylifolia while fly ash showed lowest dry matter without any inoculants. P. cematea were best in coalmine soil and W. sominifera in copper mine soil without mycorrhizal inoculation. The mycorrhiza was found to enhance the dry matter yield. This contributed minimum 0.19% to maximum up to 422.0% in different soils as compared to uninoculated plants. The mycorrhizal dependency was noticed maximum in plants grown in fly ash followed by coal mine soil, copper mine soil, skeletal soil and forest soil. The mycorrhizal response was increased maximum in W. sominifera due to survival in fly ash after inoculation followed by P corylifolia and P cematea. Percent root colonization in inoculated plant was increased minimum of 1.10 fold to maximum of 12.0 folds in comparison to un-inoculated plants . The native mycorrhiza fungi were also observed to colonize 4.0 to 32.0% roots in plants understudy. This study suggests that mycorrhizal inoculation increased the dry matter yield of medicinal plants in all soils under study. It also helps in survival of W. sominifera in fly ash.

Effects of solution chemistry on arsenic(V) removal by low-cost adsorbents.

PubMed

Wang, Yuru; Tsang, Daniel C W

2013-11-01

Natural and anthropogenic arsenic (As) contamination of water sources pose serious health concerns, especially for small communities in rural areas. This study assessed the applicability of three industrial byproducts (coal fly ash, lignite, and green waste compost) as the low-cost adsorbents for As(V) removal under various field-relevant conditions (dissolved oxygen, As(V)/Fe ratio, solution pH, and presence of competing species). The physico-chemical properties of the adsorbents were characterized by XRD, XRF, FT-IR, and NMR analysis. Batch experiments demonstrated that coal fly ash could provide effective As(V) removal (82.1%-95%) because it contained high content of amorphous iron/aluminium hydroxides for As(V) adsorption and dissolvable calcium minerals for calcium arsenate precipitation. However, the addition of lignite and green waste compost was found unfavourable since they hindered the As(V) removal by 10%-42% possibly due to dissolution of organic matter and ternary arsenate-iron-organic matter complexes. On the other hand, higher concentrations of dissolved iron (comparing As(V)/Fe ratios of 1:1 and 1:10) and dissolved oxygen (comparing 0.2 and 6 mg/L) only marginally enhanced the As(V) removal at pH 6 and 8. Thus, addition of dissolved iron, water aeration, or pH adjustment became unnecessary because coal fly ash was able to provide effective As(V) removal under the natural range of geochemical conditions. Moreover, the presence of low levels of background competing (0.8 or 8 mg/L of humic acid, phosphate, and silicate) imposed little influence on As(V) removal, possibly because the high adsorption capacity of coal fly ash was far from exhaustion. These results suggested that coal fly ash was a potentially promising adsorbent that warranted further investigation.

Behavior of TiO₂ nanoparticles during incineration of solid paint waste: a lab-scale test.

PubMed

Massari, Andrea; Beggio, Marta; Hreglich, Sandro; Marin, Riccardo; Zuin, Stefano

2014-10-01

In order to assess the potential impacts posed by products containing engineered nanoparticles, it is essential to generate more data about the release of these particles from products' life cycle. Although first studies were performed to investigate the release of nanoparticles from use phase, very few data are available on the potential release from recycling or disposal of nano-enhanced products. In this work, we investigated the behavior of TiO2 nanoparticles from incineration of solid paint waste containing these particles. Solid paint debris with and without TiO2 nanoparticles were treated in a lab scale incineration plant at 950°C (combustion temperature) and in oxidizing atmosphere. The obtained ashes were also vitrified with additives and the release of Ti was finally evaluated by leaching test. From our incineration lab-scale experiment, we did not observe a release of TiO2 nanoparticles into the atmosphere, and Ti was attached to the surface of obtained solid residues (i.e. ashes). The characterization of ashes showed that TiO2 nanoparticles reacted during the incineration to give calcium titanate. Finally, a very low release of Ti was measured, less 1 mg/kg, during the leaching test of ashes vitrified with glass cullet and feldspathic inert. Our work suggests that TiO2 nanoparticles added in paints may undergo to physicochemical transformation during the incineration, and that Ti found in ashes may be strongly immobilized in glass matrix. Since this conclusion is based on lab-scale experiment, further research is required to identify which nanoparticles will be emitted to the environment from a real-word-incineration system of household hazardous waste. Copyright © 2014 Elsevier Ltd. All rights reserved.

Application of fly ash on the growth performance and translocation of toxic heavy metals within Cajanus cajan L.: implication for safe utilization of fly ash for agricultural production.

PubMed

Pandey, Vimal Chandra; Abhilash, P C; Upadhyay, Raj Narayan; Tewari, D D

2009-07-15

The present study was undertaken to examine the influence of the application of fly ash (FA) into garden soil for Cajanus cajan L. cultivation and on accumulation and translocation of hazardous metals from FA to edible part. Numerous studies have been reported on the growth and yield of agricultural crops under FA stress; however, there is a dearth of studies recommending the safe utilization of fly ash for crop production. Pot experiments were conducted on C. cajan L., a widely cultivating legume in India for its highly nutritious seeds. C. cajan L. were grown in garden soil and amended with varying concentrations of FA in a weight/weight ratio (0%, 25%, 50% and 100%; w/w). Incorporation of fly ash from 25% to 100% in garden soil increases the levels of pH, particle density, porosity and water holding capacity from 3.47% to 26.39%, 3.98% to 26.14%, 37.50% to 147.92% and 163.16% to 318.42%, respectively, than the control while bulk density decrease respectively from 8.94% to 48.89%. Pot experiment found that accumulation and translocation of heavy metals in tested plant depends on the concentration of FA. Addition of FA at lower concentration (25%) had shown positive results in most of the studied parameters of growth and yield (14.23% than control). The experimental results confirmed that lower concentration of FA (25%) is safe for C. cajan cultivation, which not only enhanced the yield of C. cajan L. significantly but also ensured the translocation of heavy metals to edible parts within the critical limits.

Lack of enhanced photocatalytic formation of iodine on particulate semiconductor mixtures.

PubMed

Karunakaran, C; Anilkumar, P; Vinayagamoorthy, P

2012-12-01

Under UV-A light illumination, formation of iodine from iodide ion on the surfaces of anatase TiO(2), ZnO, Fe(2)O(3), CeO(2), MoO(3), Bi(2)O(3), and Nb(2)O(5) increases with the concentration of iodide ion, airflow rate and light intensity and conform to the Langmuir-Hinshelwood kinetic model. Measurement of the particle size of the semiconductor oxides by light scattering method and deduction of the same from the determined specific surface area show that the oxide particles agglomerate in suspension. However, mixtures of any two listed particulate semiconductors do not show enhanced photocatalytic formation of iodine indicating absence of interparticle charge transfer. The results are rationalized. Copyright © 2012 Elsevier B.V. All rights reserved.

Effects of a layer of vegetative ash layer on wettable and water repellent soil hydrology

NASA Astrophysics Data System (ADS)

Bodí, Merche B.; Doerr, Stefan H.; Cerdà, Artemi; Mataix-Solera, Jorge

2010-05-01

Following a wildfire, a layer of vegetative ash often covers the ground until it is dissolved or redistributed by wind and water erosion. Much of the existing literature suggests that the ash layer temporally reduces infiltration by clogging soil pores or by forming a surface crust (Mallik et al., 1984; Onda et al., 2008). However, an increasing number of field-based studies have found that, at least in the short term, ash increases infiltration by storing rainfall and protecting the underlying soil from sealing (Cerdà and Doerr, 2008; Woods and Balfour, 2008). On the other hand, after a fire the soil may have produced, enhanced or reduced its water repellency (Doerr et al., 2000). Very few studies have been taken into account the interaction of the ash and the repellent soil. The layer of ash may have similar role as a litter layer in delaying runoff and reducing erosion by storing water. In order to examine this interaction, it was been made a series of experiments using a laboratory rainfall simulation. It has been assessed the effects of an ash layer i) on a wettable and water repellent soil (WDPT > 7200s), ii) with different ash thicknesses (bare soil and 5 mm, 15 mm and 30 mm of ash), iii) preceding and following the first rain after a fire when the ground is still wetted and after being partially dried. Three replicates were done, being a total of 40 simulations. The ash used was collected from a Wildfire in Teruel (Spain) during summer of 2009. The simulations were conducted in metal boxes of 30x30 cm and filled with 3 cm of soil. The slope of the box was set at 10° (17%) and the intensity applied was 78-84 mm h-1during 40 minutes. The splash detachment was determined also using four splash cups. Overland flow and subsurface drainage was collected at 1-minute intervals and the former stored every 5 min to allow determination of sediment concentrations, yield and erosion rates. Each sample was examined at the end in terms of water repellency, infiltration pattern and ash incorporation into the soil. The results show that when ash covers the wettable soil, runoff occur for a short period of time in the middle of the event. It occurred latter on time but larger in quantity as the ash thickness increases (from 0% to 2% of runoff coefficient) and at the same time drainage is reduced (from 57 to 24%). This suggests that the ash layer became saturated and produce runoff until the water is able to drain into the soil. Oppositely, in water repellent soil as ash thickness increases both runoff is reduced (from 78% to 26%) and drainage is increased (from 0 to 16%). That fact indicates a modification in the hydraulic conductivity of the repellent soil due to the pressure of the ash layer. Splash and erosion rates are bigger in water repellent soils yet erosion rates never exceed 2.5 g m-2 h-1. The fact of wetting increases the runoff and drainage rates in wettable but reduce them in the water repellent soil. An irregular infiltration pattern is observed afterwards. After drying the soil, the increase in runoff indicates a crust formation. Moreover, in water repellent soils part of the repellency is reestablished. These findings demonstrate that the interaction of the soil-ash layer should be considered and better studied in the immediate hydrological response after wildfire due to its particular behavior. References Cerdà, A. and Doerr, S.H., 2008. The effect of ash and needle cover on surface runoff and erosion in the immediate post-fire period. Catena, 74: 256-263. Doerr, S.H., Shakesby, R.A. and Walsh, R.P.D., 2000. Soil Water repellency: Its causes, characteristics and hydro-geomorphological significance. Earth Science Reviews, 51: 33-65. Mallik, A.U., Gimingham, C.H. and Rahman, A.A., 1984. Ecological effects of heater burning. I. Water infiltration, moisture retention and porosity of surface soil. Journal of Ecology, 72: 767-776. Onda, Y., Dietrich, W.E. and Booker, F., 2008. Evolution of overland flow after a severe forest fire, Point Reyes, California. Catena, 72: 13-20. Woods, S.W. and Balfour, V., 2008. The effect of ash on runoff and erosion after a forest wildfire, Montana, U.S.A. International Journal of Wildland Fire, 17(5): 535-548.

Engineered yeast for enhanced CO2 mineralization†

PubMed Central

Barbero, Roberto; Carnelli, Lino; Simon, Anna; Kao, Albert; Monforte, Alessandra d’Arminio; Riccò, Moreno; Bianchi, Daniele; Belcher, Angela

2014-01-01

In this work, a biologically catalyzed CO2 mineralization process for the capture of CO2 from point sources was designed, constructed at a laboratory scale, and, using standard chemical process scale-up protocols, was modeled and evaluated at an industrial scale. A yeast display system in Saccharomyces cerevisae was used to screen several carbonic anhydrase isoforms and mineralization peptides for their impact on CO2 hydration, CaCO3 mineralization, and particle settling rate. Enhanced rates for each of these steps in the CaCO3 mineralization process were confirmed using quantitative techniques in lab-scale measurements. The effect of these enhanced rates on the CO2 capture cost in an industrial scale CO2 mineralization process using coal fly ash as the CaO source was evaluated. The model predicts a process using bCA2- yeast and fly ash is ~10% more cost effective per ton of CO2 captured than a process with no biological molecules, a savings not realized by wild-type yeast and high-temperature stable recombinant CA2 alone or in combination. The levelized cost of electricity for a power plant using this process was calculated and scenarios in which this process compares favorably to CO2 capture by MEA absorption process are presented. PMID:25289021

Friction-Stir Welding - Heavy Inclusions in Bi-metallic welds of Al 2219/2195

NASA Technical Reports Server (NTRS)

Rietz, Ward W., Jr.

2008-01-01

Heavy Inclusions (HI) were detected for the first time by radiographic examination in aluminum alloy 2219forging/2195plate (advancing/retreating side) Friction Sir Welds (FSW) for the Space Shuttle External Tank (ET) Program. Radiographic HI indications appear as either small (approx.0.005"-0.025") individual particles or clusters of small particles. Initial work was performed to verify that the HI was not foreign material or caused by FSW pin tool debris. That and subsequent elemental analysis determined that the HI were large agglomerations of Al2Cu (theta phase), which is the strengthening precipitate in Al2219. A literature search on that subject determined that the agglomeration of phase has also been found in Al2219 bead on plate FSW [Ref. 1]. Since this was detected in ET space flight hardware, an investigative study of the effect of agglomerated theta phase particles in FSW Al2219f/2195p was performed. Numerous panels of various lengths were welded per ET weld procedures and radiographically inspected to determine if any HI was detected. Areas that had HI were sampled for room temperature and cyclic cryogenic (-423F) tensile testing and determined no significant adverse affect on mechanical properties when compared to test specimens without HI and historical data. Fracture surface examination using the Scanning Electron Microscope (SEM) revealed smaller phase agglomerations undetectable by radiographic inspection dispersed throughout the Al2219f/2195p FSW. This indicates that phase agglomeration is inherent to the Al2219f/2195p FSW process and only rarely creates agglomerations large enough to be detected by radiography. HI has not been observed in FSW of plate to plate material for either Al2219 or AL2195.

Bed material agglomeration during fluidized bed combustion. Technical progress report, 1 July, 1993--30 September, 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, R.C.; Dawson, M.R.; Noble, S.D.

Agglomerates formed in laboratory coal combustion tests were analyzed to determine the chemical and mineral reactions which lead to the cohesion of bed particles. Combustion tests were conducted at 75, 90, 100, and 120% theoretical air values. The test at 75% theoretical air resulted in the formation of bed agglomerates within 30 minutes. Agglomerates which formed at the lower theoretical air values were compared to unagglomerated bed samples by X-ray diffraction analyses. Polished thin sections of the agglomerates were made for optical and scanning electron microscopy. The results of these analyses indicate there were, in a broad sense, two typesmore » of mineralogic reactions which lead to the cohesion of bed particles in the agglomerates. One mechanism of cohesion resulted from the melting of bed particles to form a viscous material which bridged other bed particles. Based on the chemical composition of the glass (which resulted from the melt), this material was probably derived from aluminosilicate minerals in the sand bed or from clays within the coal. Because of the high iron content in these glasses (4 to 5 wt%), it is likely that iron pyrites in the coal were involved in fluxing reactions. In addition, MgO appears to be relatively high in the glasses. It is suspected that Ca-Mg carbonates (dolomite) from the bed sand are also involved in mineralogic reactions with the aluminosilicate melt. The second type of mineralogic reaction appears to be a reaction involving calcium and magnesium with other bed particles and with the aluminosilicate melt to form new mineral phases. Although the composition of these phases is somewhat variable, some resemble single-chain silicates or pyroxenes.« less

About the relevance of waviness, agglomeration, and strain on the electrical behavior of polymer composites filled with carbon nanotubes evaluated by a Monte-Carlo simulation

NASA Astrophysics Data System (ADS)

Román, Sebastián; Lund, Fernando; Bustos, Javier; Palza, Humberto

2018-01-01

In several technological applications, carbon nanotubes (CNT) are added to a polymer matrix in order to develop electrically conductive composite materials upon percolation of the CNT network. This percolation state depends on several parameters such as particle characteristics, degree of dispersion, and filler orientation. For instance, CNT aggregation is currently avoided because it is thought that it will have a negative effect on the electrical behavior despite some experimental evidence showing the contrary. In this study, the effect of CNT waviness, degree of agglomeration, and external strain, on the electrical percolation of polymer composites is studied by a three dimensional Monte-Carlo simulation. The simulation shows that the percolation threshold of CNT depends on the particle waviness, with rigid particles displaying the lowest values. Regarding the effect of CNT dispersion, our numerical results confirm that low levels of agglomeration reduce the percolation threshold of the composite. However, the threshold is shifted to larger values at high agglomeration states because of the appearance of isolated areas of high CNT concentrations. These results imply, therefore, an optimum of agglomeration that further depends on the waviness and concentration of CNT. Significantly, CNT agglomeration can further explain the broad percolation transition found in these systems. When an external strain is applied to the composites, the percolation concentration shifts to higher values because CNT alignment increases the inter-particle distances. The strain sensitivity of the composites is affected by the percolation state of CNT showing a maximum value at certain filler concentration. These results open up the discussion about the relevance in polymer composites of the dispersion state of CNT and filler flexibility towards electrically conductive composites.

Size-segregated urban aerosol characterization by electron microscopy and dynamic light scattering and influence of sample preparation

NASA Astrophysics Data System (ADS)

Marvanová, Soňa; Kulich, Pavel; Skoupý, Radim; Hubatka, František; Ciganek, Miroslav; Bendl, Jan; Hovorka, Jan; Machala, Miroslav

2018-04-01

Size-segregated particulate matter (PM) is frequently used in chemical and toxicological studies. Nevertheless, toxicological in vitro studies working with the whole particles often lack a proper evaluation of PM real size distribution and characterization of agglomeration under the experimental conditions. In this study, changes in particle size distributions during the PM sample manipulation and also semiquantitative elemental composition of single particles were evaluated. Coarse (1-10 μm), upper accumulation (0.5-1 μm), lower accumulation (0.17-0.5 μm), and ultrafine (<0.17 μm) PM fractions were collected by high volume cascade impactor in Prague city center. Particles were examined using electron microscopy and their elemental composition was determined by energy dispersive X-ray spectroscopy. Larger or smaller particles, not corresponding to the impaction cut points, were found in all fractions, as they occur in agglomerates and are impacted according to their aerodynamic diameter. Elemental composition of particles in size-segregated fractions varied significantly. Ns-soot occurred in all size fractions. Metallic nanospheres were found in accumulation fractions, but not in ultrafine fraction where ns-soot, carbonaceous particles, and inorganic salts were identified. Dynamic light scattering was used to measure particle size distribution in water and in cell culture media. PM suspension of lower accumulation fraction in water agglomerated after freezing/thawing the sample, and the agglomerates were disrupted by subsequent sonication. Ultrafine fraction did not agglomerate after freezing/thawing the sample. Both lower accumulation and ultrafine fractions were stable in cell culture media with fetal bovine serum, while high agglomeration occurred in media without fetal bovine serum as measured during 24 h.

De-agglomeration Effect of the US Pharmacopeia and Alberta Throats on Carrier-Based Powders in Commercial Inhalation Products.

PubMed

Leung, Sharon Shui Yee; Tang, Patricia; Zhou, Qi Tony; Tong, Zhenbo; Leung, Cassandra; Decharaksa, Janwit; Yang, Runyu; Chan, Hak-Kim

2015-11-01

The US pharmacopeia (USP) and Alberta throats were recently reported to cause further de-agglomeration of carrier-free powders emitted from some dry powder inhalers (DPIs). This study assessed if they have similar influences on commercially available carrier-based DPIs. A straight tube, a USP throat, and an Alberta throat (non-coated and coated) were used for cascade impaction testing. Aerosol fine particle fraction (FPF ≤ 5 μm) was computed to evaluate throat-induced de-agglomeration. Computational fluid dynamics are employed to simulate airflow patterns and particle trajectories inside the USP and Alberta throats. For all tested products, no significant differences in the in vitro aerosol performance were observed between the USP throat and the straight tube. Using fine lactose carriers (<10 μm), Symbicort(®) and Oxis(™) showed minimal impaction inside the Alberta throat and resulted in similar FPF among all induction ports. For products using coarse lactose carriers (>10 μm), impaction frequency and energy inside the Alberta throat were significant. Further de-agglomeration was noted inside the non-coated Alberta throat for Seretide(®) and Spiriva(®), but agglomerates emitted from Relenza(®), Ventolin(®), and Foradil(®) did not further break up into smaller fractions. The coated Alberta throat considerably reduced the FPF values of these products due to the high throat retention, but they generally agreed better with the in vivo data. In conclusion, depending on the powder formulation (including carrier particle size), the inhaler, and the induction port, further de-agglomeration could happen ex-inhaler and create differences in the in vitro measurements.

Fossil and active fumaroles in the 1912 eruptive deposits, Valley of ten thousand smokes, Alaska

USGS Publications Warehouse

Keith, T.E.C.

1991-01-01

Fumaroles in the ash-flow sheet emplaced during the 1912 eruption of Novarupta were intensely active throughout the Valley of Ten Thousand Smokes (VTTS) when first studied in 1917. Fumarole temperatures recorded in 1919 were as hot as 645??C. Influx of surface waters into the hot ash-flow sheet provided the fluid flow to sustain the fumaroles but also enhanced cooling so that by the mid-1930's vigorous activity survived only in the vent region. Configuration and distribution of high-temperature fissure fumaroles tens of meters long, that are prevalent in the middle and upper VTTS, were controlled largely by sintering and degree of welding, which in turn controlled fracturing and permeability of the ash-flow tuff. One fracture type developed parallel to the enclosing valley walls during compaction of the ash-flow sheet. Another type extends across the VTTS nearly perpendicular to the flow direction. A third type of randomly oriented fractures developed as cooling contraction cracks during vapor-phase devitrification. In distal parts of the ash-flow sheet where the tuff is nonwelded, prominent fumaroles have irregular funnel-shaped morphologies. Fumarole distribution in the nonwelded part of the ash-flow sheet is concentrated above pre-emplacement river channels. The hottest, longest-lived fumaroles occurred in the upper VTTS near the 1912 vent where the ash-flow sheet is thicker, more indurated, and on average more mafic (richer in dacite and andesite) in contrast to the thinner, nonwelded rhyolitic tuff in the distal part of the sheet. Fumarolic activity was less intense in the distal part of the tuff because of lower emplacement temperatures, more diffuse fumarole conduits in the nonwelded tuff, and the thinness of the ash-flow sheet. Chemical leaching of ash-flow tuff by hot rising fluids took place adjacent to fumarolic conduits in deep parts of the fumaroles. Deposition of incrustation minerals, the components of which were carried upward by fumarolic gases, took place in the upper part of the ejecta, mostly in the fallout layers. The permeability difference between the ash-flow tuff and the overlying coarse dacite fallout was a critical factor in promoting the abrupt gradients in temperature, pressure, and fO2 that resulted in deposition of minerals from the fumarolic gases. The permeability difference between nonwelded ash-flow tuff and overlying fine-grained fall layers in the lower VTTS is less pronounced. The total mass of fumarolically deposited minerals appears large at first glance owing to the conspicuous coloration by Fe minerals; the mass is appreciably less than is apparent, however, because most incrustations are composed largely of ejecta coated or cemented by fine-grained fumarolic minerals. A large mass of unstable incrustation minerals, mainly chlorides and sulfates, reported during the 1917-1919 studies have since been removed by dissolution and weathering. In the vent region, argillic alteration that followed high-temperature degassing is localized along arcuate subsidence fractures in fallback ejecta. At widely scattered residual orifices, fumarolic gases presently are near-neutral steam, and temperatures are as hot as 90??C. ?? 1991.

Transitioning from High School to College: Surviving a Clash of Educational Cultures. ASHE Annual Meeting Paper.

ERIC Educational Resources Information Center

Lee, Wynetta Y.

This study examined the role of the North Carolina State University Transition Program (UTP) in enhancing transition of disadvantaged students from high school and increasing their persistence to degree. The UTP, which targets academically underprepared African American and Native American students, provides special courses and counseling…

Strategic Planning and Fiscal Benefits: Is There a Link? ASHE Annual Meeting Paper.

ERIC Educational Resources Information Center

Swenk, Jean M.

This study attempted to determine whether strategic planning would enhance a higher education institution's fiscal condition. It also systematically evaluated the extent of institution-wide strategic planning among private four-year postsecondary institutions in the United States. A definition of strategic planning and a conceptual framework based…

Ash characteristics and plant nutrients in some aquatic biomasses

NASA Astrophysics Data System (ADS)

Masto, Reginald; Pandit, Ankita; George, Joshy; Mukhopadhyay, Sangeeta; Selvi, Vetrivel; Ram, Lal

2016-04-01

Aquatic biomasses are explored as potential fuel source for direct combustion because of their faster growth and no land requirement. The energy density and the ash characteristics of the aquatic biomasses are to be evaluated for their suitability for energy extraction. In the study, four aquatic plant samples namely Eichornia crassipes, Hydrilla verticilleta, Lemna minor, Spirogyra spp were collected from a pond in Digwadih Campus of Central Institute of Mining and Fuel Research, Dhanbad. The biomasses were air dried, powdered and ashed at different temperatures. Volatile C was relatively lower in Spirogyra and Hydrilla (53 %) than Eichornia (62.6 %) or Lemna (59.7 %), whereas fixed C was higher for Eichornia and Lemna (about 10 %) and lower for Hydrilla (1 %). Ultimate analysis showed that the carbon content was in the order Eichornia > Lemna > Spirogyra > Hydrilla. The IR spectra of each raw biomass is compared to their respective ashes obtained at different temperatures (500-900°C). With increase in ashing temperature from 500-900°C there is gradual breakdown of the cellulosic structure hence, peaks around 2900-2800cm-1 caused by aliphatic C-H vibration tends to disappear slowly in ash. More number of peaks appears at lower wavenumbers in ashes of all the biomass samples indicating towards increased percentage of inorganic ion species. Considerable enrichment of SiO2 is validated with prominent peaks at 1100-900 cm-1 in all the ashes. Lemna and Spirogyra has a similar ash composition (Si > Al > Ca > K), whereas, Ca was higher in Hydrilla (Si > Ca > K > Al). Eichornia (Si > K > Ca > Al) has higher K and Ca than Al. SiO2 and Al2O3 were higher in Spirogyra, while SiO2 and CaO in Eichornia and Hydrilla. K first increased from 500-700/800⁰C, and then decreased from 800-900⁰C. Cl is lost slowly in ash from 500-700/800⁰C and then by a drastic reduction from 800-900⁰C. S is enhanced in ash at all temperatures although the change is quite small. Most of the Cl is released at 800 °C. The salgging tendencies based on both base: acid ratio and slagging factor, fouling probabilities based on fouling factors is in the order Hydrilla > Eichornia > Lemna > Spirogyra. Among the different heavy metals Zn, Pb, Cu, and Ni have concentration > 100 mg/kg; Cr and V content was > 50 mg/kg; Co, > 10 mg/kg. In general the heavy metal contents were higher in Spirogyra. Due to the volatile nature Cd and Pb decreases in ash with temperature and is lost continuously in flue gas. Plant nutrient content was relatively higher for Eichornia: K (8 - 12.8 %), P (5.7 - 7.3 %), Ca (9.2 - 10.8 %), Mg (2.8 - 3.6 %), S (1.9 - 2.9 %), Zn (0.033 - 0.045 %), Fe (3.3 - 4.7 %), Cu (0.009 - 0.013 %), Mn (0.8 -1.3%). Among the four biomasses we have studied, Eichornia could be a potential candidate for energy extraction in view of its C content and widespread availability in many parts of the globe, and fast multiplication associated with the eutrophication of water bodies.

Microwave enhanced oxidation treatment of organic fertilizers.

PubMed

More, Abhilasha; Srinivasan, Asha; Liao, Ping Huang; Lo, Kwang Victor

2017-08-01

Liquid organic fertilizers (LOFs) are relatively easier to degrade than those of solid organic fertilizers, and the nutrients are readily available for plant uptake. Microwave enhanced advanced oxidation treatment (MW/H 2 O 2 -AOP) was used to convert solid organic fertilizers (insoluble blood meal, bone meal, feather meal, sunflower ash and a mixture) into LOF. After the MW/H 2 O 2 -AOP treatment, high soluble nitrogen (11-29%), soluble phosphorus (64%) and potassium (92%), as well as low total suspended solids content could be obtained. The resulting LOF would make the nutrients more bioavailable, and would provide some of them for the plant uptake immediately. Temperature and hydrogen peroxide dosage were found to be significant factors affecting nitrogen release from blood meal and feather meal, while temperature and pH were found to be significant factors for solubilizing phosphorus and potassium from bone meal and ash, respectively. The MW/H 2 O 2 -AOP reduced suspended solids, and released nutrients into solution; therefore, it was an effective treatment method to make LOFs. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Effect of metal tolerant plant growth promoting bacteria on growth and metal accumulation in Zea mays plants grown in fly ash amended soil.

PubMed

Kumar, Kalpna V; Patra, D D

2013-01-01

The present study was undertaken to examine the effect of the application of fly ash (FA) into Garden soil (GS), with and without inoculation of plant growth promoting bacteria (PGPB), on the growth and metal uptake by Zea mays plants. Three FA tolerant PGPB strains, Pseudomonas sp. PS5, PS14, and Bacillus sp. BC29 were isolated from FA contaminated soils and assessed for their plant growth promoting features on the Z. mays plants. All three strains were also examined for their ability to solubilize phosphate and to produce Indole Acetic Acid (IAA), siderophores, and hydrogencynide acid (HCN) production. Although inoculation of all strains significantly enhanced the growth of plants at both the concentration of FA but maximum growth was observed in plants inoculated with BC29 and PS14 at low level (25%) of FA concentration. The experimental results explored the plant growth promoting features of selected strains which not only enhanced growth and biomass of plants but also protected them from toxicity of FA.

An experimental investigation on mechanical behaviour of eco - friendly concrete

NASA Astrophysics Data System (ADS)

Narender Reddy, A.; Meena, T.

2017-11-01

Fly ash (FA) and Alccofine are the eco-friendly materials that can be used in the production of concrete composites. Initially, concrete mixes of M30 grade with replacement of cement by 0%, 5%, 10%, 15%, 20% and 25% by weight of Fly ash were prepared. They were subjected to compression test so as to select the optimum replacement percentage of FA. Keeping this optimum percentage of FA as constant, additional replacement of cement with Alccofine was done varying its replacement in the range of 8%, 10%, 12% and 14%. The mechanical properties such as compressive, split tensile and flexural strengths of these mixes were computed for 7, 14 and 28 days. The results of Eco-Friendly Concrete (EFC) are compared with those of control concrete. It was observed that EFC mixes exhibited superior qualities like quick setting and enhanced workability, their mechanical properties were found to be higher than that of the conventional concrete. This goes to prove that the combination of FA and Alccofine together as replacement for cement would enhance the properties of EFC.

Recovery of Rare Earth Elements from Coal and Coal Byproducts via a Closed Loop Leaching Process: Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peterson, Richard; Heinrichs, Michael; Argumedo, Darwin

Objectives: Through this grant, Battelle proposes to address Area of Interest (AOI) 1 to develop a bench-scale technology to economically separate, extract, and concentrate mixed REEs from coal ash. U.S. coal and coal byproducts provide the opportunity for a domestic source of REEs. The DOE’s National Energy Technology Laboratory (NETL) has characterized various coal and coal byproducts samples and has found varying concentrations of REE ranging up to 1,000 parts per million by weight. The primary project objective is to validate the economic viability of recovering REEs from the coal byproduct coal ash using Battelle’s patented closed-loop Acid Digestion Processmore » (ADP). This will be accomplished by selecting coal sources with the potential to provide REE concentrations above 300 parts per million by weight, collecting characterization data for coal ash samples generated via three different methods, and performing a Techno-Economic Analysis (TEA) for the proposed process. The regional availability of REE-laden coal ash, the regional market for rare earth concentrates, and the system capital and operating costs for rare earth recovery using the ADP technology will be accounted for in the TEA. Limited laboratory testing will be conducted to generate the parameters needed for the design of a bench scale system for REE recovery. The ultimate project outcome will be the design for an optimized, closed loop process to economically recovery REEs such that the process may be demonstrated at the bench scale in a Phase 2 project. Project Description: The project will encompass evaluation of the ADP technology for the economic recovery of REEs from coal and coal ash. The ADP was originally designed and demonstrated for the U.S. Army to facilitate demilitarization of cast-cured munitions via acid digestion in a closed-loop process. Proof of concept testing has been conducted on a sample of Ohio-based Middle Kittanning coal and has demonstrated the feasibility of recovering REEs using the ADP technology. In AOI 1, Ohio coal sources with the potential to provide a consistent source of rare earth element concentrations above 300 parts per million will be identified. Coal sample inventories from West Virginia and Pennsylvania will also be assessed for purposes of comparison. Three methods of preparing the coal ash will be evaluated for their potential to enhance the technical feasibility and economics of REE recovery. Three sources of coal ash are targeted for evaluation of the economics of REE recovery in this project: (1) coal ash from power generation stations, to include fly ash and/or bottom ash, (2) ash generated in a lower temperature ashing process, and (3) ash residual from Battelle’s coal liquefaction process. Making use of residual ash from coal liquefaction processes directly leverages work currently being conducted by Battelle for DOE NETL in response to DE-FOA-0000981 entitled “Greenhouse Gas Emissions Reductions Research and Development Leading to Cost-Competitive Coal-to-Liquids Based Jet Fuel Production.” Using the sample characterization results and regional information regarding REE concentration, availability and cost, a TEA will be developed. The previously generated laboratory testing results for leaching and REE recovery via the ADP will be used to perform the TEA, along with common engineering assumptions for scale up of equipment and labor costs. Finally, upon validation of the economic feasibility of the process by the TEA, limited laboratory testing will be performed to support the design of a bench scale system. In a future project phase, it is envisioned that the bench scale system will be constructed and operated to prove the process on a continuous basis.« less

Growth of Larval Agrilus planipennis (Coleoptera: Buprestidae) and Fitness of Tetrastichus planipennisi (Hymenoptera: Eulophidae) in Blue Ash (Fraxinus quadrangulata) and Green Ash (F. pennsylvanica).

PubMed

Peterson, Donnie L; Duan, Jian J; Yaninek, J S; Ginzel, Matthew D; Sadof, Clifford S

2015-12-01

Emerald ash borer (Agrilus planipennis Fairmaire) is an invasive primary pest of North American ash (Fraxinus spp.) trees. Blue ash (F. quadrangulata) is less susceptible to emerald ash borer infestations in the forest than other species of North American ash. Whereas other studies have examined adult host preferences, we compared the capacity of emerald ash borer larvae reared from emerald ash borer eggs in the field and in the laboratory to survive and grow in blue ash and the more susceptible green ash (F. pennsylvanica). Emerald ash borer larval survivorship was the same on both ash species. Mortality due to wound periderm formation was only observed in living field grown trees, but was low (<4%) in both green and blue ash. No difference in larval mortality in the absence of natural enemies suggests that both green and blue ash can support the development of emerald ash borer. Larvae reared from eggs on blue ash were smaller than on green ash growing in the field and also in bolts that were infested under laboratory conditions. In a laboratory study, parasitism rates of confined Tetrastichus planipennisi were similar on emerald ash borer larvae reared in blue and green ash bolts, as were fitness measures of the parasitoid including brood size, sex ratio, and adult female size. Thus, we postulate that emerald ash borer larvae infesting blue ash could support populations of T. planipennisi and serve as a potential reservoir for this introduced natural enemy after most of the other native ash trees have been killed. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Science in Support of Aviation-Risk Management since the April 2010 Eruption of Eyjafjallajökull, Iceland

NASA Astrophysics Data System (ADS)

Guffanti, M.; Mastin, L. G.; Schneider, D. J.; Tupper, A.

2010-12-01

The nearly week-long airspace closure over large parts of Europe and the North Atlantic in April 2010 that resulted from dispersion of ash from the eruption of Eyjafjallajökull prompted a shift from the accepted global policy of strict avoidance by aircraft of ash-contaminated airspace to one of allowing flight through zones of dilute ash under some circumstances. This shift was made in a crisis environment of rapidly mounting economic losses and social disruptions extending well beyond the European region. To get the global air transportation system moving again, European aviation authorities and associated meteorological offices created a new type of advisory product depicting forecasted zones of low ash concentrations in Eyjafjallajökull’s clouds that could be transited with expectation of no or minimal risk of aircraft damage, under the condition of more frequent aircraft inspections and enhanced risk management by airlines. Preliminary data of the European Aviation Safety Agency indicate that transit through Eyjafjallajökull’s dilute ash clouds caused some wear (primarily abrasion) to a few aircraft, but not to the severity of degraded engine performance in flight; after inspections the aircraft were returned to service and continued to operate without problems. Following the crisis, recognizing that such a fundamental shift in risk management requires sound scientific and engineering bases, the International Civil Aviation Organization (ICAO) formed an International Volcanic Ash Task Force that, in conjunction with the World Meteorological Organization (WMO), will incorporate advice and recommendations from scientific, aviation, and engineering experts worldwide about ways to improve (1) situational awareness to aviation users of impending volcanic eruptions, (2) characterization of critical eruption source parameters for incorporation in forecast modeling, (3) detection and characterization of volcanic clouds, (4) accuracy of volcanic ash transport and dispersion models, and (5) airworthiness of engine, avionics, and airframes by manufacturers and airlines. Ground-based, airborne, and space-based methods are being evaluated in terms of the above items, and results of pertinent scientific investigations of the eruption and volcanic cloud are being compiled. Key topical issues being addressed include the need to depict uncertainty in quantitative modeling of ash concentration and capabilities to visualize and compare geospatial data from different sources. The timeline for this work extends over the next 3 years. More information about the ICAO and WMO scientific advisory process for volcanic ash hazards is at http://www2.icao.int/en/anb/met-aim/met/ivatf/Lists/Meetings/AllItems.aspx/. This process is still being refined, but participation from the broader scientific community within the IVATF framework is crucial to its success.

OXIDATIVE STRESS AND LIPID MEDIATORS INDUCED IN ALVEOLAR MACHROPHAGES BY ULTRAFINE PARTICLES

EPA Science Inventory

In ambient aerosols, ultrafine particles (UFP) and their agglomerates are considered to be major factors contributing to adverse health effects. Reactivity of agglomerated UFP of elemental carbon (EC), Printex 90, Printex G, and diesel exhaust particles (DEP) was evaluated by the...

Assessment of morphological and functional changes in organs of rats after intramuscular introduction of iron nanoparticles and their agglomerates.

PubMed

Sizova, Elena; Miroshnikov, Sergey; Yausheva, Elena; Polyakova, Valentina

2015-01-01

The research was performed on male Wistar rats based on assumptions that new microelement preparations containing metal nanoparticles and their agglomerates had potential. Morphological and functional changes in tissues in the injection site and dynamics of chemical element metabolism (25 indicators) in body were assessed after repeated intramuscular injections (total, 7) with preparation containing agglomerate of iron nanoparticles. As a result, iron depot was formed in myosymplasts of injection sites. The quantity of muscle fibers having positive Perls' stain increased with increasing number of injections. However, the concentration of the most chemical elements and iron significantly decreased in the whole skeletal muscle system (injection sites are not included). Consequently, it increased up to the control level after the sixth and the seventh injections. Among the studied organs (liver, kidneys, and spleen), Caspase-3 expression was revealed only in spleen. The expression had a direct dependence on the number of injections. Processes of iron elimination from preparation containing nanoparticles and their agglomerates had different intensity.

Effect of whey protein agglomeration on spray dried microcapsules containing Saccharomyces boulardii.

PubMed

Duongthingoc, Diep; George, Paul; Katopo, Lita; Gorczyca, Elizabeth; Kasapis, Stefan

2013-12-01

This work investigates the effect of whey protein agglomeration on the survivability of Saccharomyces boulardii within spray dried microcapsules. It attempts to go beyond phenomenological observations by establishing a relationship between physicochemical characteristics of the polymeric matrix and its effect on probiotic endurance upon spray drying. It is well known that this type of thermal shock has lethal consequences on the yeast cells. To avoid such undesirable outcome, we take advantage of the early agglomeration phenomenon observed for whey protein by adjusting the pH value of preparations close to isoelectric point (pH 4-5). During the subsequent process of spray drying, development of whey protein agglomerates induces formation of an early crust, and the protein in this molten globular state creates a cohesive network encapsulating the yeast cells. It appears that the early crust formation at a given sample pH and temperature regime during spray drying benefits the survivability of S. boulardii within microcapsules. Copyright © 2013. Published by Elsevier Ltd.

Diamond-like-carbon nanoparticle production and agglomeration following UV multi-photon excitation of static naphthalene/helium gas mixtures

NASA Astrophysics Data System (ADS)

Walsh, A. J.; Tielens, A. G. G. M.; Ruth, A. A.

2016-07-01

We report the formation of nanoparticles with significant diamond character after UV multi-photon laser excitation of gaseous naphthalene, buffered in static helium gas, at room temperature. The nanoparticles are identified in situ by their absorption and scattering spectra between 400 and 850 nm, which are modeled using Mie theory. Comparisons of the particles' spectroscopic and optical properties with those of carbonaceous materials indicate a sp3/sp2 hybridization ratio of 8:1 of the particles formed. The particle extinction in the closed static (unstirred) gas-phase system exhibits a complex and quasi-oscillatory time dependence for the duration of up to several hours with periods ranging from seconds to many minutes. The extinction dynamics of the system is based on a combination of transport features and particle interaction, predominantly agglomeration. The relatively long period of agglomeration allows for a unique analysis of the agglomeration process of diamond-like carbon nanoparticles in situ.

Stacked multilayers of alternating reduced graphene oxide and carbon nanotubes for planar supercapacitors.

PubMed

Moon, Geon Dae; Joo, Ji Bong; Yin, Yadong

2013-12-07

A simple layer-by-layer approach has been developed for constructing 2D planar supercapacitors of multi-stacked reduced graphene oxide and carbon nanotubes. This sandwiched 2D architecture enables the full utilization of the maximum active surface area of rGO nanosheets by using a CNT layer as a porous physical spacer to enhance the permeation of a gel electrolyte inside the structure and reduce the agglomeration of rGO nanosheets along the vertical direction. As a result, the stacked multilayers of rGO and CNTs are capable of offering higher output voltage and current production.

Occurrence of emerald ash borer (Coleoptera: Buprestidae) and biotic factors affecting its immature stages in the Russian Far East.

PubMed

Duan, Jian J; Yurchenko, Galina; Fuester, Roger

2012-04-01

Field surveys were conducted from 2008 to 2011 in the Khabarovsk and Vladivostok regions of Russia to investigate the occurrence of emerald ash borer, Agrilus planipennis Fairmaire, and mortality factors affecting its immature stages. We found emerald ash borer infesting both introduced North American green ash (Fraxinus pennsylvanica Marshall) and native oriental ashes (F. mandshurica Rupr. and F. rhynchophylla Hance) in both regions. Emerald ash borer densities (larvae/m(2) of phloem area) were markedly higher on green ash (11.3-76.7 in the Khabarovsk area and 77-245 in the Vladivostok area) than on artificially stressed Manchurian ash (2.2) or Oriental ash (10-59). Mortality of emerald ash borer larvae caused by different biotic factors (woodpecker predation, host plant resistance and/or undetermined diseases, and parasitism) varied with date, site, and ash species. In general, predation of emerald ash borer larvae by woodpeckers was low. While low rates (3-27%) of emerald ash borer larval mortality were caused by undetermined biotic factors on green ash between 2009 and 2011, higher rates (26-95%) of emerald ash borer larval mortality were caused by putative plant resistance in Oriental ash species in both regions. Little (<1%) parasitism of emerald ash borer larvae was observed in Khabarovsk; however, three hymenopteran parasitoids (Spathius sp., Atanycolus nigriventris Vojnovskaja-Krieger, and Tetrastichus planipennisi Yang) were observed attacking third - fourth instars of emerald ash borer in the Vladivostok area, parasitizing 0-8.3% of emerald ash borer larvae infesting Oriental ash trees and 7.3-62.7% of those on green ash trees (primarily by Spathius sp.) in two of the three study sites. Relevance of these findings to the classical biological control of emerald ash borer in newly invaded regions is discussed.

High volume production of nanostructured materials

DOEpatents

Ripley, Edward B [Knoxville, TN; Morrell, Jonathan S [Knoxville, TN; Seals, Roland D [Oak Ridge, TN; Ludtka, Gerard M [Oak Ridge, TN

2009-10-13

A system and method for high volume production of nanoparticles, nanotubes, and items incorporating nanoparticles and nanotubes. Microwave, radio frequency, or infrared energy vaporizes a metal catalyst which, as it condenses, is contacted by carbon or other elements such as silicon, germanium, or boron to form agglomerates. The agglomerates may be annealed to accelerate the production of nanotubes. Magnetic or electric fields may be used to align the nanotubes during their production. The nanotubes may be separated from the production byproducts in aligned or non-aligned configurations. The agglomerates may be formed directly into tools, optionally in compositions that incorporate other materials such as abrasives, binders, carbon-carbon composites, and cermets.

Methods for high volume production of nanostructured materials

DOEpatents

Ripley, Edward B [Knoxville, TN; Morrell, Jonathan S [Knoxville, TN; Seals, Roland D [Oak Ridge, TN; Ludtka, Gerald M [Oak Ridge, TN

2011-03-22

A system and method for high volume production of nanoparticles, nanotubes, and items incorporating nanoparticles and nanotubes. Microwave, radio frequency, or infrared energy vaporizes a metal catalyst which, as it condenses, is contacted by carbon or other elements such as silicon, germanium, or boron to form agglomerates. The agglomerates may be annealed to accelerate the production of nanotubes. Magnetic or electric fields may be used to align the nanotubes during their production. The nanotubes may be separated from the production byproducts in aligned or non-aligned configurations. The agglomerates may be formed directly into tools, optionally in compositions that incorporate other materials such as abrasives, binders, carbon-carbon composites, and cermets.

Universities' Entrepreneurial Performance: The Role of Agglomeration Economies

ERIC Educational Resources Information Center

Chen, Ping Penny

2011-01-01

In spite of the extensive research on universities' entrepreneurship, whether research strength fosters or dampens their entrepreneurial performance remains controversial. Much research claims an influential role of research universities in regional economy, however, little has been said about what a part that the agglomeration economies may play…

How Does the Concentration of Determinants Affect Industrial Innovation Performance? - An Empirical Analysis of 23 Chinese Industrial Sectors.

PubMed

Huang, Shansong; Bai, Yang; Tan, Qingmei

2017-01-01

The agglomeration of innovation determinants has a significant influence on the innovation performance of industries and enterprises. Such an effect has received less attention in empirical research studies. This study involves a survey of the agglomeration effect of two important innovation determinants, R&D investment and R&D personnel, and its influence on innovation performance from the perspective of the industrial level. We analysed the agglomeration features based on the panel data of 23 Chinese industrial sectors from 2001~2013. An interpretation model is proposed to examine the agglomeration effect on innovation performance for 4 industrial groups: state-owned enterprises, individual enterprises, foreign-owned enterprises and enterprises as a whole. We found two main results. First, the agglomeration of determinants has a clear positive effect on the innovation performance of all 4 groups but affects individual enterprises more significantly, followed by state-owned and foreign-owned enterprises. Second, the state-owned enterprises show a much higher concentration of R&D investment and R&D personnel than other groups. However, the induced innovation efficiency in the state-owned enterprises is worse than in the individual enterprises. The advantage of resources and capital does not translate into corresponding innovation output. The privately owned small and medium-sized enterprises (SMEs) show a high capability of technological innovation and mercerization but have limited innovation resources.

How Does the Concentration of Determinants Affect Industrial Innovation Performance? – An Empirical Analysis of 23 Chinese Industrial Sectors

PubMed Central

Huang, Shansong; Bai, Yang; Tan, Qingmei

2017-01-01

The agglomeration of innovation determinants has a significant influence on the innovation performance of industries and enterprises. Such an effect has received less attention in empirical research studies. This study involves a survey of the agglomeration effect of two important innovation determinants, R&D investment and R&D personnel, and its influence on innovation performance from the perspective of the industrial level. We analysed the agglomeration features based on the panel data of 23 Chinese industrial sectors from 2001~2013. An interpretation model is proposed to examine the agglomeration effect on innovation performance for 4 industrial groups: state-owned enterprises, individual enterprises, foreign-owned enterprises and enterprises as a whole. We found two main results. First, the agglomeration of determinants has a clear positive effect on the innovation performance of all 4 groups but affects individual enterprises more significantly, followed by state-owned and foreign-owned enterprises. Second, the state-owned enterprises show a much higher concentration of R&D investment and R&D personnel than other groups. However, the induced innovation efficiency in the state-owned enterprises is worse than in the individual enterprises. The advantage of resources and capital does not translate into corresponding innovation output. The privately owned small and medium-sized enterprises (SMEs) show a high capability of technological innovation and mercerization but have limited innovation resources. PMID:28099452

Nanoparticle growth and surface chemistry changes in cell-conditioned culture medium.

PubMed

Kendall, Michaela; Hodges, Nikolas J; Whitwell, Harry; Tyrrell, Jess; Cangul, Hakan

2015-02-05

When biomolecules attach to engineered nanoparticle (ENP) surfaces, they confer the particles with a new biological identity. Physical format may also radically alter, changing ENP stability and agglomeration state within seconds. In order to measure which biomolecules are associated with early ENP growth, we studied ENPs in conditioned medium from A549 cell culture, using dynamic light scattering (DLS) and linear trap quadrupole electron transfer dissociation mass spectrometry. Two types of 100 nm polystyrene particles (one uncoated and one with an amine functionalized surface) were used to measure the influence of surface type. In identically prepared conditioned medium, agglomeration was visible in all samples after 1 h, but was variable, indicating inter-sample variability in secretion rates and extracellular medium conditions. In samples conditioned for 1 h or more, ENP agglomeration rates varied significantly. Agglomerate size measured by DLS was well correlated with surface sequestered peptide number for uncoated but not for amine coated polystyrene ENPs. Amine-coated ENPs grew much faster and into larger agglomerates associated with fewer sequestered peptides, but including significant sequestered lactose dehydrogenase. We conclude that interference with extracellular peptide balance and oxidoreductase activity via sequestration is worthy of further study, as increased oxidative stress via this new mechanism may be important for cell toxicity. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Colloidal properties and stability of aqueous suspensions of few-layer graphene: Importance of graphene concentration

PubMed Central

Su, Yu; Yang, Guoqing; Lu, Kun; Petersen, Elijah J.; Mao, Liang

2017-01-01

Understanding the colloidal stability of graphene is essential for predicting its transport and ecological risks in aquatic environments. We investigated the agglomeration of 14C-labeled few-layer graphene (FLG) at concentrations spanning nearly four orders of magnitude (2 μg/L to 10 mg/L) using dynamic light scattering and sedimentation measurements. FLG agglomerates formed rapidly in deionized water at concentrations > 3 mg/L. From 1 mg/L to 3 mg/L, salt-induced agglomeration was decreased with dilution of FLG suspensions; the critical coagulation concentration of the more concentrated suspension (3 mg/L) was significantly lower than the dilute suspension (1 mg/L) in the presence of NaCl (1.6 mmol/L and 10 mmol/L, respectively). In contrast, FLG underwent slow agglomeration and settling at concentrations ≤ 0.1 mg/L in NaCl solutions and ambient waters with low ionic strength (< 10 mmol/L). Although salt-induced agglomeration led to 67 % reduction in number of small FLG (25 nm to 50 nm) according to atomic force microscopy characterization, transition from concentrated to dilute suspension retarded the removal of the small FLG. Additionally, the small FLG exhibited greater bioaccumulation in zebrafish embryo and stronger chorion penetration ability than larger ones. These findings suggest that FLG at more environmentally relevant concentration is relatively stable and may have implications for exposure of small FLG to ecological receptors. PMID:27720543

Agglomeration of Celecoxib by Quasi Emulsion Solvent Diffusion Method: Effect of Stabilizer.

PubMed

Maghsoodi, Maryam; Nokhodchi, Ali

2016-12-01

Purpose: The quasi-emulsion solvent diffusion (QESD) has evolved into an effective technique to manufacture agglomerates of API crystals. Although, the proposed technique showed benefits, such as cost effectiveness, that is considerably sensitive to the choice of a stabilizer, which agonizes from a absence of systemic understanding in this field. In the present study, the combination of different solvents and stabilizers were compared to investigate any connections between the solvents and stabilizers. Methods: Agglomerates of celecoxib were prepared by QESD method using four different stabilizers (Tween 80, HPMC, PVP and SLS) and three different solvents (methyl acetate, ethyl acetate and isopropyl acetate). The solid state of obtained particles was investigated by differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) spectroscopy. The agglomerated were also evaluated in term of production yield, distribution of particles and dissolution behavior. Results: The results showed that the effectiveness of stabilizer in terms of particle size and particle size distribution is specific to each solvent candidate. A stabilizer with a lower HLB value is preferred which actually increased its effectiveness with the solvent candidates with higher lipophilicity. HPMC appeared to be the most versatile stabilizer because it showed a better stabilizing effect compared to other stabilizers in all solvents used. Conclusion: This study demonstrated that the efficiency of stabilizers in forming the celecoxib agglomerates by QESD was influenced by the HLB of the stabilizer and lipophilicity of the solvents.

Use of plant residues for improving soil fertility, pod nutrients, root growth and pod weight of okra (Abelmoschus esculentum L).

PubMed

Moyin-Jesu, Emmanuel Ibukunoluwa

2007-08-01

The effect of wood ash, sawdust, ground cocoa husk, spent grain and rice bran upon root development, ash content, pod yield and nutrient status and soil fertility for okra (Abelmoschus esculentum L NHAe 47 variety) was studied. The five organic fertilizer treatments were compared to chemical fertilizer (400kg/ha/crop NPK 15-15-15) and unfertilized controls in four field experiments replicated four times in a randomized complete block design. The results showed that the application of 6tha(-1) of plant residues increased (P<0.05) the soil N, P, K, Ca, Mg, pH, and SOM; pod N, P, K, Ca, Mg and ash; root length; and pod yield of okra in all four experiments relative to the control treatment. For instance, spent grain treatment increased the okra pod yield by 99%, 33%, 50%, 49%, 65% and 67% compared to control, NPK, wood ash, cocoa husk, rice bran and sawdust treatments respectively. In the stepwise regression, out of the total R(2) value of 0.83 for the soil nutrients to the pod yield of okra; soil N accounted for 50% of the soil fertility improvement and yield of okra. Spent grain, wood ash and cocoa husk were the most effective in improving okra pod weight, pod nutrients, ash content, root length and soil fertility whereas the rice bran and sawdust were the least effective. This was because the spent grain, wood ash and cocoa husk had lower C/N ratio and higher nutrient composition than rice bran and sawdust, thus, the former enhanced an increase in pod nutrients, composition for better human dietary intake, increased the root length, pod weight of okra and improved soil fertility and plant nutrition crop. The significance of the increases in okra mineral nutrition concentration by plant residues is that consumers will consume more of these minerals in their meals and monetarily spend less for purchasing vitamins and mineral supplement drugs to meet health requirements. In addition, the increase in plant nutrition and soil fertility would help to reduce the high cost of buying synthetic inorganic fertilizers and maintain the long term productivity of soils for sustainable cultivation of okra.

Interspecific Proteomic Comparisons Reveal Ash Phloem Genes Potentially Involved in Constitutive Resistance to the Emerald Ash Borer

PubMed Central

Whitehill, Justin G. A.; Popova-Butler, Alexandra; Green-Church, Kari B.; Koch, Jennifer L.; Herms, Daniel A.; Bonello, Pierluigi

2011-01-01

The emerald ash borer (Agrilus planipennis) is an invasive wood-boring beetle that has killed millions of ash trees since its accidental introduction to North America. All North American ash species (Fraxinus spp.) that emerald ash borer has encountered so far are susceptible, while an Asian species, Manchurian ash (F. mandshurica), which shares an evolutionary history with emerald ash borer, is resistant. Phylogenetic evidence places North American black ash (F. nigra) and Manchurian ash in the same clade and section, yet black ash is highly susceptible to the emerald ash borer. This contrast provides an opportunity to compare the genetic traits of the two species and identify those with a potential role in defense/resistance. We used Difference Gel Electrophoresis (DIGE) to compare the phloem proteomes of resistant Manchurian to susceptible black, green, and white ash. Differentially expressed proteins associated with the resistant Manchurian ash when compared to the susceptible ash species were identified using nano-LC-MS/MS and putative identities assigned. Proteomic differences were strongly associated with the phylogenetic relationships among the four species. Proteins identified in Manchurian ash potentially associated with its resistance to emerald ash borer include a PR-10 protein, an aspartic protease, a phenylcoumaran benzylic ether reductase (PCBER), and a thylakoid-bound ascorbate peroxidase. Discovery of resistance-related proteins in Asian species will inform approaches in which resistance genes can be introgressed into North American ash species. The generation of resistant North American ash genotypes can be used in forest ecosystem restoration and urban plantings following the wake of the emerald ash borer invasion. PMID:21949771

Interspecific proteomic comparisons reveal ash phloem genes potentially involved in constitutive resistance to the emerald ash borer.

PubMed

Whitehill, Justin G A; Popova-Butler, Alexandra; Green-Church, Kari B; Koch, Jennifer L; Herms, Daniel A; Bonello, Pierluigi

2011-01-01

The emerald ash borer (Agrilus planipennis) is an invasive wood-boring beetle that has killed millions of ash trees since its accidental introduction to North America. All North American ash species (Fraxinus spp.) that emerald ash borer has encountered so far are susceptible, while an Asian species, Manchurian ash (F. mandshurica), which shares an evolutionary history with emerald ash borer, is resistant. Phylogenetic evidence places North American black ash (F. nigra) and Manchurian ash in the same clade and section, yet black ash is highly susceptible to the emerald ash borer. This contrast provides an opportunity to compare the genetic traits of the two species and identify those with a potential role in defense/resistance. We used Difference Gel Electrophoresis (DIGE) to compare the phloem proteomes of resistant Manchurian to susceptible black, green, and white ash. Differentially expressed proteins associated with the resistant Manchurian ash when compared to the susceptible ash species were identified using nano-LC-MS/MS and putative identities assigned. Proteomic differences were strongly associated with the phylogenetic relationships among the four species. Proteins identified in Manchurian ash potentially associated with its resistance to emerald ash borer include a PR-10 protein, an aspartic protease, a phenylcoumaran benzylic ether reductase (PCBER), and a thylakoid-bound ascorbate peroxidase. Discovery of resistance-related proteins in Asian species will inform approaches in which resistance genes can be introgressed into North American ash species. The generation of resistant North American ash genotypes can be used in forest ecosystem restoration and urban plantings following the wake of the emerald ash borer invasion.

Do Aloe vera and Ageratum conyzoides enhance the anti-microbial activity of traditional medicinal soft soaps (Osedudu)?

PubMed

Moody, J O; Adebiyi, O A; Adeniyi, B A

2004-05-01

The Nigerian traditional soft soaps prepared using varied locally sourced raw materials such as cocoa pod ash (Theobroma cacao) palm kernel shaft ash (Elaies guineensis) have been evaluated for their physico-chemical properties and anti-microbial activities using standard pharmacopoeia protocols and an in-vitro agar diffusion bioassay method. The anti-microbial evaluation was done with and without incorporation of Aloe vera and Ageratum conyzoides extractives into the soap samples. Results showed that the physico-chemical properties of the soaps are dependent on the raw materials utilised. The incorporated medicinal plants used in this study, however, did not show any significant effect on the anti-microbial activities exhibited by the various soaps against the bacterial and fungal test organisms. Copyright 2004 Elsevier Ireland Ltd.

Treatment of fly ash for use in concrete

DOEpatents

Boxley, Chett [Park City, UT

2012-05-15

A process for treating fly ash to render it highly usable as a concrete additive. A quantity of fly ash is obtained that contains carbon and which is considered unusable fly ash for concrete based upon foam index testing. The fly ash is mixed with a quantity of spray dryer ash (SDA) and water to initiate a geopolymerization reaction and form a geopolymerized fly ash. The geopolymerized fly ash is granulated. The geopolymerized fly ash is considered usable fly ash for concrete according to foam index testing. The geopolymerized fly ash may have a foam index less than 40%, and in some cases less than 20%, of the foam index of the untreated fly ash. An optional alkaline activator may be mixed with the fly ash and SDA to facilitate the geopolymerization reaction. The alkaline activator may contain an alkali metal hydroxide, carbonate, silicate, aluminate, or mixtures thereof.

Treatment of fly ash for use in concrete

DOEpatents

Boxley, Chett [Park City, UT; Akash, Akash [Salt lake City, UT; Zhao, Qiang [Natick, MA

2012-05-08

A process for treating fly ash to render it highly usable as a concrete additive. A quantity of fly ash is obtained that contains carbon and which is considered unusable fly ash for concrete based upon foam index testing. The fly ash is mixed with an activator solution sufficient to initiate a geopolymerization reaction and for a geopolymerized fly ash. The geopolymerized fly ash is granulated. The geopolymerized fly ash is considered usable fly ash for concrete according to foam index testing. The geopolymerized fly ash may have a foam index less than 35% of the foam index of the untreated fly ash, and in some cases less than 10% of the foam index of the untreated fly ash. The activator solution may contain an alkali metal hydroxide, carbonate, silicate, aluminate, or mixtures thereof.

Treatment of fly ash for use in concrete

DOEpatents

Boxley, Chett; Akash, Akash; Zhao, Qiang

2013-01-08

A process for treating fly ash to render it highly usable as a concrete additive. A quantity of fly ash is obtained that contains carbon and which is considered unusable fly ash for concrete based upon foam index testing. The fly ash is mixed with an activator solution sufficient to initiate a geopolymerization reaction and for a geopolymerized fly ash. The geopolymerized fly ash is granulated. The geopolymerized fly ash is considered usable fly ash for concrete according to foam index testing. The geopolymerized fly ash may have a foam index less than 35% of the foam index of the untreated fly ash, and in some cases less than 10% of the foam index of the untreated fly ash. The activator solution may contain an alkali metal hydroxide, carbonate, silicate, aluminate, or mixtures thereof.

Synergistic effect of biogenic Fe3+ coupled to S° oxidation on simultaneous bioleaching of Cu, Co, Zn and As from hazardous Pyrite Ash Waste.

PubMed

Panda, Sandeep; Akcil, Ata; Mishra, Srabani; Erust, Ceren

2017-03-05

Pyrite ash, a waste by-product formed during roasting of pyrite ores, is a good source of valuable metals. The waste is associated with several environmental issues due to its dumping in sea and/or land filling. Although several other management practices are available for its utilization, the waste still awaits and calls for an eco-friendly biotechnological application for metal recovery. In the present study, chemolithotrophic meso-acidophilic iron and sulphur oxidisers were evaluated for the first time towards simultaneous mutli-metal recovery from pyrite ash. XRD and XRF analysis indicated higher amount of Hematite (Fe 2 O 3 ) in the sample. ICP-OES analysis indicated concentrations of Cu>Zn>Co>As that were considered for bioleaching. Optimization studies indicated Cu - 95%, Co - 97%, Zn - 78% and As - 60% recovery within 8days at 10% pulp density, pH - 1.75, 10% (v/v) inoculum and 9g/L Fe 2+ . The productivity of the bioleaching system was found to be Cu - 1696ppm/d (12% dissolution/d), Co - 338ppm/d (12.2% dissolution/d), Zn k 576ppm/d (9.8% dissolution/d) and As - 75ppm/d (7.5% dissolution/d). Synergistic actions for Fe 2+ - S° oxidation by iron and sulphur oxidisers were identified as the key drivers for enhanced metal dissolution from pyrite ash sample. Copyright © 2016 Elsevier B.V. All rights reserved.

Higher Education Leadership: Enhancing Skills through Professional Development Programs. ASHE/ERIC Higher Education Report No. 5, 1987.

ERIC Educational Resources Information Center

McDade, Sharon A.

The responsibilities and skills of college administrators and training needs and programs are discussed. After tracing typical career paths of administrators, skills and knowledge that they need are identified, based in part on similar positions from government, service organizations, and the military. The list of administrators' responsibilities…

The High Teperature Influence on Geopolymer Fly Ash Mixture’s Compressisive Strength with Insudtrial Waste Material Substitution

NASA Astrophysics Data System (ADS)

Bayuaji, R.; Wibowo, B.; Subekti, S.; Santoso, S. E.; Hardiyanto, E.; Kaelani, Y.; Mallu, L. L.

2017-11-01

This research aimed to figure out the influence of fly ash mixture from the industrial waste at the temperatures of 150°C, 450°C, 750°C viewed from the strength and resistance of geopolymer paste. As a result, cement will be substituted by industrial waste like fly ash. This experimental research was conducted on the mix design of geopolymer concrete which was made by dimension with 2.5 cm in diameter and 5 cm in height from four mixture composition of fly ash and industrial waste i.e. 100% fly ash, 50% fly ash+50% bottom ash, 50% fly ash+50% sandblast, and 50% fly ash+50% carbide waste. Each mixture was tested in terms of porosity and compressive strength. In conclusion, in the mixture of 50% fly ash+50% Sandblast and 50% fly ash+50% bottom ash in 12 molars, 1.5 activator comparison can be used to substitute fly ash at high temperature. Meanwhile, the mixture of 50% fly ash+50% carbide waste in 8 molars, 0.5 activator comparison has very small strength remaining if it is compared to the mixture of fly ash and other industrial waste (Bottom ash and Sandblast). The performance of mixture paste of 50% fly ash+50% carbide waste was very vulnerable after being burnt. Consequently, it cannot be used as the main structure at high temperature.

Synthesis and characterization of gold/water nanofluids suitable for thermal applications produced by femtosecond laser radiation

NASA Astrophysics Data System (ADS)

Mondragón, Rosa; Torres-Mendieta, Rafael; Meucci, Marco; Mínguez-Vega, Gladys; Enrique Juliá, J.; Sani, Elisa

2016-07-01

A laser-based "green" synthesis of nanoparticles (NPs) was used to manufacture gold NPs in water. The light source is a Ti:Sapphire laser with 30 fs FWHM pulses, 800 nm mean wavelength, and 1 kHz repetition rate. The method involves two stages: (1) pulsed laser ablation in liquids and (2) photo-fragmentation (PF). Highly pure and well-dispersed NPs with a diameter of 18.5 nm that can be stored at room temperature without showing any agglomeration over a period of at least 3 months were produced without the need to use any stabilizer. Transmittance spectra, extinction coefficient, NPs agglomeration dynamics, and thermal conductivity of the nanofluids obtained were analyzed before and after being submitted to thermal cycling and compared to those obtained for commercial gold/water suspensions. Optical properties have also been investigated, showing no substantial differences for thermal applications between NPs produced by the laser ablation and PF technique and commercial NPs. Therefore, nanofluids produced by this technique can be used in thermal applications, which are foreseen for conventional nanofluids, e.g., heat transfer enhancement and solar radiation direct absorption, but offering the opportunity to produce them in situ in almost any kind of fluid without the production of any chemical waste.

The effect of carbon black loading and structure on tensile property of natural rubber composite

NASA Astrophysics Data System (ADS)

Savetlana, S.; Zulhendri; Sukmana, I.; Saputra, F. A.

2017-07-01

Natural rubber composite has been continuously developed due to its advantages such as a good combination of strength and damping property. Most of carbon black (CB)/Natural Rubber (NR) composite were used as material in tyre industry. The addition of CB in natural rubber is very important to enhance the strength of natural rubber. The particle loading and different structure of CB can affect the composite strength. The effects of CB particle loading of 20, 25 and 30 wt% and the effects of CB structures of N220, N330, N550 and N660 series on tensile property of composite were investigated. The result shows that the tensile strength and elastic modulus of natural rubber/CB composite was higher than pure natural rubber. From SEM observation the agglomeration of CB aggregate increases with particle loading. It leads to decrease of tensile strength of composite as more particle was added. High structure of CB particle i.e. N220 resulted in highest tensile stress. In fact, composite reinforced by N660 CB particle shown a comparable tensile strength and elastic modulus with N220 CB particle. SEM observation shows that agglomeration of CB aggregates of N330 and N550 results in lower stress of associate NR/CB composite.

Insights into the role of wettability in cathode catalyst layer of proton exchange membrane fuel cell; pore scale immiscible flow and transport processes

NASA Astrophysics Data System (ADS)

Fathi, H.; Raoof, A.; Mansouri, S. H.

2017-05-01

The production of liquid water in cathode catalyst layer, CCL, is a significant barrier to increase the efficiency of proton exchange membrane fuel cell. Here we present, for the first time, a direct three-dimensional pore-scale modelling to look at the complex immiscible two-phase flow in CCL. After production of the liquid water at the surface of CCL agglomerates due to the electrochemical reactions, water spatial distribution affects transport of oxygen through the CCL as well as the rate of reaction at the agglomerate surfaces. To explore the wettability effects, we apply hydrophilic and hydrophobic properties using different surface contact angles. Effective diffusivity is calculated under several water saturation levels. Results indicate larger diffusive transport values for hydrophilic domain compared to the hydrophobic media where the liquid water preferentially floods the larger pores. However, hydrophobic domain showed more available surface area and higher oxygen consumption rate at the reaction sites under various saturation levels, which is explained by the effect of wettability on pore-scale distribution of water. Hydrophobic domain, with a contact angle of 150, reveals efficient water removal where only 28% of the pore space stays saturated. This condition contributes to the enhanced available reaction surface area and oxygen diffusivity.

Nutritional and defensive chemistry of three North American ash species: possible roles in host performance and preference by emerald ash borer

Treesearch

Yigen Chen; Therese M. Poland

2010-01-01

Black ash (Fraxinus nigra), green ash (F. pennsylvanica), and white ash (F. americana) are the three most abundant ash species in the northeastern USA. We compared emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), adult performance and preference among seedlings...

Effects of nano-SiO(2) and different ash particle sizes on sludge ash-cement mortar.

PubMed

Lin, K L; Chang, W C; Lin, D F; Luo, H L; Tsai, M C

2008-09-01

The effects of nano-SiO(2) on three ash particle sizes in mortar were studied by replacing a portion of the cement with incinerated sewage sludge ash. Results indicate that the amount of water needed at standard consistency increased as more nano-SiO(2) was added. Moreover, a reduction in setting time became noticeable for smaller ash particle sizes. The compressive strength of the ash-cement mortar increased as more nano-SiO(2) was added. Additionally, with 2% nano-SiO(2) added and a cure length of 7 days, the compressive strength of the ash-cement mortar with 1 microm ash particle size was about 1.5 times better that of 75microm particle size. Further, nano-SiO(2) functioned to fill pores for ash-cement mortar with different ash particle sizes. However, the effects of this pore-filling varied with ash particle size. Higher amounts of nano-SiO(2) better influenced the ash-cement mortar with larger ash particle sizes.

Combined Effect of Ultrasound Stimulations and Autoclaving on the Enhancement of Antibacterial Activity of ZnO and SiO₂/ZnO Nanoparticles.

PubMed

Rokbani, Hajer; Daigle, France; Ajji, Abdellah

2018-02-25

This study investigates the antibacterial activity (ABA) of suspensions of pure ZnO nanoparticles (ZnO-NPs) and mesoporous silica doped with ZnO (ZnO-UVM7), as well as electrospun nanofibers containing those nanoparticles. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of these two materials were also determined under the same conditions. The results showed a concentration-dependent effect of antibacterial nanoparticles on the viability of Escherichia coli ( E. coli ). Moreover, the combination of the stimulations and sterilization considerably enhanced the antimicrobial activity (AMA) of the ZnO suspensions. Poly (lactic acid) (PLA) solutions in 2,2,2-trifluoroethanol (TFE) were mixed with different contents of nanoparticles and spun into nonwoven mats by the electrospinning process. The morphology of the mats was analyzed by scanning electron microscopy (SEM). The amount of nanoparticles contained in the mats was determined by thermogravimetric analysis (TGA). The obtained PLA-based mats showed a fibrous morphology, with an average diameter ranging from 350 to 450 nm, a porosity above 85%, but with the nanoparticles agglomeration on their surface. TGA analysis showed that the loss of ZnO-NPs increased with the increase of ZnO-NPs content in the PLA solutions and reached 79% for 1 wt % of ZnO-NPs, which was mainly due to the aggregation of nanoparticles in solution. The ABA of the obtained PLA mats was evaluated by the dynamic method according to the ASTM standard E2149. The results showed that, above an optimal concentration, the nanoparticle agglomeration reduced the antimicrobial efficiency of PLA mats. These mats have potential features for use as antimicrobial food packaging material.

Role of Cu During Sintering of Fe0.96Cu0.04 Nanoparticles

NASA Astrophysics Data System (ADS)

Sivaprahasam, D.; Sriramamurthy, A. M.; Bysakh, S.; Sundararajan, G.; Chattopadhyay, K.

2018-04-01

Nanoparticle agglomerates of passivated Fe ( n-Fe) and Fe0.96Cu0.04 ( n-Fe0.96Cu0.04), synthesized through the levitational gas condensation (LGC) process, were compacted and sintered using the conventional powder metallurgy method. The n-Fe0.96Cu0.04 agglomerates produced lower green density than n-Fe, and when compacted under pressure beyond 200 MPa, they underwent lateral cracking during ejection attributed to the presence of a passive oxide layer. Sintering under dynamic hydrogen atmosphere can produce a higher density of compact in n-Fe0.96Cu0.04 in comparison to n-Fe. Both the results of dilatometry and thermogravimetric (TG) measurements of the samples under flowing hydrogen revealed enhancement of the sintering process as soon as the reduction of oxide layers could be accomplished. The shrinkage rate of n-Fe0.96Cu0.04 reached a value three times higher than n-Fe at a low temperature of 723 K (450 °C) during heating. This enhanced shrinkage rate was the manifestation of accumulation of Cu at the surface of the particles. The formation of a thin-surface melted layer enriched with copper during heating to isothermal holding facilitated as a medium of transport for diffusion of the elements. The compacts produced by sintering at 773 K (500 °C), with relative density 82 pct, were found to be unstable and oxidized instantly when exposed to ambient atmosphere. The stable compacts of density more than 92 pct with 300- to 450-nm grain size could only be produced when sintering was carried out at 973 K (700 °C) and beyond. The 0.22 wt pct residual oxygen obtained in the sintered compact is similar to what is used for conventional ferrous powder metallurgy products.