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1

POC-Scale Testing of Oil Agglomeration Techniques and Equipment for Fine Coal Processing  

SciTech Connect

The objective of this project is to develop and demonstrate a Proof-of-Concept (POC) scale oil agglomeration technology capable of increasing the recovery and improving the quality of fine coal strearrts. Two distinct agglomeration devices will be tested, namely, a conventional high shear mixer and a jet processor. To meet the overall objective an eleven task work plan has been designed. The work ranges from batch and continuous bench-scale testing through the design, commissioning and field testing of POC-scale agglomeration equipment.

None

1998-11-12

2

POC-scale testing of oil agglomeration techniques and equipment for fine coal processing  

SciTech Connect

This report covers the technical progress achieved from January 1, 1998 to April 31, 1998 on the POC-Scale Testing of Oil Agglomeration Techniques and Equipment for Fine Coal Processing. Experimental work was carried out with two coal fines. One sample originated from pond (Drummond Pond Fines) while the second was pulverized Luscar Mine coal. Both samples were tested at the laboratory batch-scale while only Luscar Mine Coal was processed on the 250 kg/h continuous system. Significant progress was made on optimization of process conditions for Pond Fines. The test results showed that ash could be reduced by about 42% at combustible recovery exiting 94%. It was also found that pond fines required significantly longer conditioning time than freshly pulverized run of mine coal. Continuous bench-scale testing carried out with Luscar Mine coal included rod mill calibration, plant equipment and instrumentation check-up, and parametric studies. Compared with batch-scale tests, the continuous bench-scale process required more bridging oil to achieve similar process performance. During the current reporting period work has been commenced on the final engineering and preparation of design package of 3t/h POC-scale unit.

W. Pawlak; K. Szymocha

1998-04-01

3

Low-rank coal oil agglomeration  

DOEpatents

A low-rank coal oil agglomeration process. High mineral content, a high ash content subbituminous coals are effectively agglomerated with a bridging oil which is partially water soluble and capable of entering the pore structure, and usually coal derived.

Knudson, Curtis L. (Grand Forks, ND); Timpe, Ronald C. (Grand Forks, ND)

1991-01-01

4

Low-rank coal oil agglomeration  

DOEpatents

A low-rank coal oil agglomeration process is described. High mineral content, a high ash content subbituminous coals are effectively agglomerated with a bridging oil which is partially water soluble and capable of entering the pore structure, and is usually coal-derived.

Knudson, C.L.; Timpe, R.C.

1991-07-16

5

Selective oil agglomeration of lignite  

SciTech Connect

In this study, desulfurization and deashing of Adiyaman-Glbai lignite by the agglomeration method were studied. For this purpose, three groups of agglomeration experiments were made. The effects of solid concentration, bridging liquid type and dosage, pH, and screen size on the agglomeration after desliming were investigated in the first group of experiments. The effects of lake water and sea water (the Mediterranean Sea water, the Aegean Sea water, and the Black Sea water) on the agglomeration were investigated in the second group of experiments. The effects of different salts (NaCl, MgCl{sub 2}, and FeCl{sub 3}) on the agglomeration were investigated in the third group of experiments. Agglomeration results showed that the usage of sea waters and soda lake water in the agglomeration medium had a positive effect on the reduction of total sulfur content of agglomerates. In addition, the usage of NaCl, MgCl{sub 2}, and FeCl{sub 3} in the agglomeration medium had a positive effect on the ash content reduction of the agglomerates. 27 refs., 10 figs., 6 tabs.

Halime Abakay Temel; Volkan Bozkurt; Arun Kumar Majumder [Dicle University, Diyarbakir (Turkey). Department of Mining Engineering

2009-01-15

6

POC-scale testing of oil agglomeration techniques and equipment for fine coal processing: technical progress report no. 3--January 1, 1996-March 31, 1996  

SciTech Connect

The objective of this project is to develop and demonstrate a Proof-of-Concept (POC) scale oil agglomeration technology capable of increasing the recovery and improving the quality of fine coal streams. Two distinct agglomeration devices will be tested, namely, a conventional high shear mixer and a tubular (jet) processor. To meet the overall objective an 11 task work plan has been designed. The work will range from batch and continuous bench-scale testing through the design, commissioning and field testing of POC-scale agglomeration equipment. During the reporting period there were activities under the following tasks: project planning and management; host site selection and plan formulation; preliminary engineering and design of POC equipment; coal characterization and laboratory (batch) and bench-scale testing; and process evaluation. The work on the remaining tasks is scheduled for the next months.

NONE

1996-10-01

7

Factors affecting the oil agglomeration of Sivas-Divrigi Ulucayir lignite  

SciTech Connect

In the coal industry, the coal particles need to be decreased to a very fine size because of the need of removing inorganic materials from coal. Oil agglomeration is a kind of coal cleaning technique that is used for separation of organic and inorganic parts of fine sized coal. In this study, the oil agglomeration of Sivas-Divrigi (S-D) Ulucayir lignite was carried out by using kerosene, diesel oil, fuel oil, poppy oil, and sunflower oil. The amount of bridging oil was varied from 5% to 25% of the amount of lignite. The effect of oil amount, oil type, solid content, agitation rate and time, pH on agglomeration performance was investigated. Maximum recovery value of 98.18% was observed by using poppy oil. In order to investigate the effect of pH on agglomeration NaOH and HCl is added to the slurry in various amounts. It is decided that the best agglomeration condition is obtained at low pH values. The effect of nonionic surface active agent (Igepal-CA 630) on agglomeration is investigated by adding to the slurry and it is observed that the grade is increased with the amount of surface active agent.

Unal, I.; Gorgun Ersan, M. [Cumhuriyet University, Sivas (Turkey)

2007-07-01

8

Development of a Gas-Promoted Oil Agglomeration Process  

SciTech Connect

The preliminary laboratory-scale development of a gas-promoted, oil agglomeration process for cleaning coal was carried out with scale model mixing systems in which aqueous suspensions of ultrafine coal particles were treated with a liquid hydrocarbon and a small amount of air. The resulting agglomerates were recovered by screening. During a batch agglomeration test the progress of agglomeration was monitored by observing changes in agitator torque in the case of concentrated suspensions or by observing changes in turbidity in the case of dilute suspensions. Dilute suspensions were employed for investigating the kinetics of agglomeration, whereas concentrated suspensions were used for determining parameters that characterize the process of agglomeration. A key parameter turned out to be the minimum time te required to produce compact spherical agglomerates. Other important parameters included the projected area mean particle diameter of the agglomerates recovered at the end of a test as well as the ash content and yield of agglomerates. Batch agglomeration tests were conducted with geometrically similar mixing tanks which ranged in volume from 0.346 to 11.07 liters. Each tank was enclosed to control the amount of air present. A variable speed agitator fitted with a six blade turbine impeller was used for agitation. Tests were conducted with moderately hydrophobic Pittsburgh No. 8 coal and with more hydrophobic Upper Freeport coal using either n-heptane, i-octane, or hexadecane as an agglomerant.

C. Nelson; F. Zhang; J. Drzymala; M. Shen; R. Abbott; T. D. Wheelock

1997-11-01

9

Low-rank coal oil agglomeration product and process  

DOEpatents

A selectively-sized, raw, low-rank coal is processed to produce a low ash and relative water-free agglomerate with an enhanced heating value and a hardness sufficient to produce a non-decrepitating, shippable fuel. The low-rank coal is treated, under high shear conditions, in the first stage to cause ash reduction and subsequent surface modification which is necessary to facilitate agglomerate formation. In the second stage the treated low-rank coal is contacted with bridging and binding oils under low shear conditions to produce agglomerates of selected size. The bridging and binding oils may be coal or petroleum derived. The process incorporates a thermal deoiling step whereby the bridging oil may be completely or partially recovered from the agglomerate; whereas, partial recovery of the bridging oil functions to leave as an agglomerate binder, the heavy constituents of the bridging oil. The recovered oil is suitable for recycling to the agglomeration step or can serve as a value-added product.

Knudson, Curtis L. (Grand Forks, ND); Timpe, Ronald C. (Grand Forks, ND); Potas, Todd A. (Plymouth, MN); DeWall, Raymond A. (Grand Forks, ND); Musich, Mark A. (Grand Forks, ND)

1992-01-01

10

Low-rank coal oil agglomeration product and process  

DOEpatents

A selectively-sized, raw, low-rank coal is processed to produce a low ash and relative water-free agglomerate with an enhanced heating value and a hardness sufficient to produce a non-degradable, shippable fuel. The low-rank coal is treated, under high shear conditions, in the first stage to cause ash reduction and subsequent surface modification which is necessary to facilitate agglomerate formation. In the second stage the treated low-rank coal is contacted with bridging and binding oils under low shear conditions to produce agglomerates of selected size. The bridging and binding oils may be coal or petroleum derived. The process incorporates a thermal deoiling step whereby the bridging oil may be completely or partially recovered from the agglomerate; whereas, partial recovery of the bridging oil functions to leave as an agglomerate binder, the heavy constituents of the bridging oil. The recovered oil is suitable for recycling to the agglomeration step or can serve as a value-added product.

Knudson, C.L.; Timpe, R.C.; Potas, T.A.; DeWall, R.A.; Musich, M.A.

1992-11-10

11

Basic principles and mechanisms of selective oil agglomeration  

SciTech Connect

Numerous measurements of the heat of immersion of coal were conducting using several different particle size fractions of No. 2 Gas Seam coal from Raleigh County, West Virginia. The heat of immersion was determined in water, methanol, heptane, hexadecane and neohexane (2,2-dimethybutane). A comparison of the results with those determined previously for Illinois No. 6 coal is discussed. A number of potential pyrite depressants for use in oil agglomeration of coal were screened by testing the response of sulfidized mineral pyrite to agglomeration with heptane in the presence of the potential depressant. The following were tested; sodium dithionite, sodium thiosulfate, ferrous sulfate, ferric sulfate, titanous chloride, hydrogen peroxide, Oxone (a form of potassium monopersulfate), pyrogallol, quebracho (colloidal dispersant derived from tree bark), milk whey, and several organic thiols. Ferric chloride was applied to mixtures of Upper Freeport coal and sulfidized mineral pyrite before subjecting the mixtures to agglomeration with heptane. 7 refs., 23 figs., 3 tabs.

Wheelock, T.D.; Drzymala, J.; Allen, R.W.; Hu, Y.-C.; Tyson, D.; Xiaoping, Qiu; Lessa, A.

1990-01-01

12

Relationship between properties of oil\\/water emulsion and agglomeration of carbonate minerals  

Microsoft Academic Search

In this study, a modification of oil agglomeration processes of dolomite and magnesite particles has been proposed. In this method the emulsion of kerosene with dodecylammonium hydrochloride (DDAHCl) was added to the minerals suspension. The experimental results have demonstrated that the agglomeration was governed by the properties of oil\\/water interface such as zeta potential and interfacial tension (?o\\/w). Addition of

Anna Bastrzyk; Izabela Polowczyk; Zygmunt Sadowski; Andrzej Sikora

2011-01-01

13

TEM and HRTEM of Soot-in-oil particles and agglomerates from internal combustion engines  

NASA Astrophysics Data System (ADS)

Over time, the performance of lubricating oil in a diesel engine is affected by the build-up of carbon soot produced by the combustion process. TEM and HRTEM are commonly used to investigate the characteristics of individual and agglomerated particles from diesel exhaust, to understand the structure and distribution of the carbon sheets in the primary particles and the nanostructure morphology. However, high resolution imaging of soot-in-oil is more challenging, as mineral oil is a contaminant for the electron microscope and leads to instability under the electron beam. In this work we compare solvent extraction and centrifugation techniques for removing the mineral oil contaminant, and the effect on particle size distribution.

Fay, M. W.; La Rocca, A.; Shayler, P. J.

2014-06-01

14

APPLICATION OF OIL AGGLOMERATION FOR EFFLUENT CONTROL FROM COAL CLEANING PLANTS  

EPA Science Inventory

The report discusses the potential applicability of oil agglomeration for the control of black water effluents from coal cleaning plants processing four different coals. Removal and recovery of the coal from each of the black waters produced aqueous suspensions of mineral matter ...

15

Development of a gas-promoted oil agglomeration process. Quarterly technical progress report, July 1, 1995--September 30, 1995  

SciTech Connect

The preliminary laboratory-scale development of a gas-promoted, oil agglomeration process for cleaning coal advanced in three major research areas. One area of research resulted in the development of a method for measuring the rate of agglomeration of dilute particle suspensions and using the method to relate the rate of agglomeration of coal particles to various key parameters. A second area of research led to the development of a method for monitoring a batch agglomeration process by measuring changes in agitator torque. With this method it was possible to show that the agglomeration of a concentrated coal particle suspension is triggered by the introduction of a small amount of gas. The method was also used in conjunction with optical microscopy to study the mechanism of agglomeration. A third area of research led to the discovery that highly hydrophobic particles in an aqueous suspension can be agglomerated by air alone.

Wheelock, T.D.

1995-12-31

16

Development of a gas-promoted oil agglomeration process. Technical progress report, April 1, 1995--June 30, 1995  

SciTech Connect

Several scale model mixing systems have been built and are being utilized to study the gas-promoted, oil agglomeration process for cleaning coal. Numerous batch agglomeration tests have been conducted with these systems. During an individual test the progress of agglomeration has been monitored by observing either changes in agitator torque in the case of concentrated particle suspensions or changes in turbidity in the case of dilute suspensions. A mathematical model has been developed for relating the rate of agglomeration of coal particles to the rate of change of turbidity of a dilute particle suspension undergoing agglomeration. The model has been utilized for analyzing and interpreting the results of a number of oil agglomeration tests in which several different system parameters were varied.

Wheelock, T.D.

1995-12-01

17

Oil encapsulation by spray drying and fluidised bed agglomeration  

Microsoft Academic Search

Many active components (anti-oxidants, aromas) are lipophilic substances, available in liquid form and have to be protected from the environment. Encapsulation of oil drops into a solid matrix is regarded as an efficient protection method and a means of formulating liquid compounds in a solid dosed form.The aim of this study is to investigate the feasibility of encapsulation of a

C. Turchiuli; M. Fuchs; M. Bohin; M. E. Cuvelier; C. Ordonnaud; M. N. Peyrat-Maillard; E. Dumoulin

2005-01-01

18

Mechanisms for selective agglomeration of coals  

SciTech Connect

Work continued on the basic mechanisms which underlie various processes for beneficiating aqueous suspensions of coal by selective agglomeration with oil. A new method was demonstrated for characterizing the agglomerability of coal suspensions. This method utilizes a photometric dispersion analyzer to monitor changes in the turbidity of a particle suspension as increasing amounts of oil are added to the suspension in a batch agglomeration test. Agglomeration of the particles leads to a marked decrease in the turbidity of the suspension. Another experimental technique was also demonstrated for characterizing oil agglomeration. This technique involves measuring the rate of growth of agglomerates in a continuous flow system operating under stead-state conditions. The data are analyzed by means of a population balance. The results of a preliminary set of experiments in which Indiana V seam coal was agglomerated with tetralin seemed to fit a particular growth model very well. Equipment was also constructed for studying the kinetics of agglomeration in a batch process. While earlier work showed that quebracho (a commercially available dispersant) is a strong agglomeration depressant for pyrite, recent experiments with mixtures of Upper Freeport coal and mineral pyrite showed that quebracho does not appear to be sufficiently selective. Further consideration was given to the separation of mixtures of coal and pyrite agglomeration with heptane. 2 refs., 17 figs., 1 tab.

Wheelock, T.D.; Drzymala, J.; Allen, R.W.; Hu, Y.-C.; Tyson, D.; Xiaoping, Qiu; Lessa, A.

1989-05-01

19

Assessing mobility and redistribution patterns of sand and oil agglomerates in the surf zone  

USGS Publications Warehouse

Heavier-than-water sand and oil agglomerates that formed in the surf zone following the Deepwater Horizon oil spill continued to cause beach re-oiling 3 years after initial stranding. To understand this phenomena and inform operational response now and for future spills, a numerical method to assess the mobility and alongshore movement of these “surface residual balls” (SRBs) was developed and applied to the Alabama and western Florida coasts. Alongshore flow and SRB mobility and potential flux were used to identify likely patterns of transport and deposition. Results indicate that under typical calm conditions, cm-size SRBs are unlikely to move alongshore, whereas mobility and transport is likely during storms. The greater mobility of sand compared to SRBs makes burial and exhumation of SRBs likely, and inlets were identified as probable SRB traps. Analysis of field data supports these model results.

Dalyander, P. Soupy; Long, Joesph W.; Plant, Nathaniel G.; Thompson, David M.

2014-01-01

20

Assessing mobility and redistribution patterns of sand and oil agglomerates in the surf zone.  

PubMed

Heavier-than-water sand and oil agglomerates that formed in the surf zone following the Deepwater Horizon oil spill continued to cause beach re-oiling 3years after initial stranding. To understand this phenomena and inform operational response now and for future spills, a numerical method to assess the mobility and alongshore movement of these "surface residual balls" (SRBs) was developed and applied to the Alabama and western Florida coasts. Alongshore flow and SRB mobility and potential flux were used to identify likely patterns of transport and deposition. Results indicate that under typical calm conditions, cm-size SRBs are unlikely to move alongshore, whereas mobility and transport is likely during storms. The greater mobility of sand compared to SRBs makes burial and exhumation of SRBs likely, and inlets were identified as probable SRB traps. Analysis of field data supports these model results. PMID:24503377

Dalyander, P Soupy; Long, Joseph W; Plant, Nathaniel G; Thompson, David M

2014-03-15

21

Desulfurization and de-ashing of a mixture of subbituminous coal and gangue minerals by selective oil agglomeration  

SciTech Connect

The aim of this study was to investigate desulfurization and de-ashing of a mixture of subbituminous coal and gangue minerals by the agglomeration method. For this purpose, experimental studies were conducted on a mixture containing subbituminous coal, pyrite, quartz and calcite. The effects of some parameters that markedly influence the effectiveness of selective oil agglomeration, such as solid concentration, pH, bridging liquid type and concentration, and depressant type and amount, were investigated. Agglomeration results showed that the usage of various depressants (Na{sub 2}SiO{sub 3}, FeCl3, corn starch, wheat starch) in the agglomeration medium has a positive effect on the reduction of ash and total sulfur content of agglomerates. It was found that an agglomerate product containing 3.03% total sulfur and 25.01% ash with a total sulfur reduction of 56.71% was obtained from a feed that contained 7% total sulfur and 43.58% ash when FeCl{sub 3} was used in the agglomeration medium.

Ayhan, F.D. [Dicle University, Diyarbakir (Turkey). Dept. of Mining Engineering

2009-11-15

22

Development of a gas-promoted oil agglomeration process. Technical progress report, April 1, 1994--June 30, 1994  

SciTech Connect

The overall purpose of this research project is to carry out the preliminary laboratory-scale development of a gas-promoted, oil agglomeration process for cleaning coal using model mixing systems. The design and construction of a model mixing system for conducting oil agglomeration tests were reported previously as well as the results of a series of calibration and shakedown tests. The system consists of a flat bottom tank which is fitted with four vertical baffles, a cover, and a turbine agitator. The tank has an inside diameter of 15.24 cm (6.0 in.), height of 15.24 cm (6.0 in.), and net volume of 2.87 L. The tank is connected to a photometric dispersion analyzer so that the turbidity of a coal particle suspension undergoing agglomeration can be monitored. Measuring the turbidity of a particle suspension requires application of the Beer-Lambert law. However, since this law applies for dilute suspensions, it is questionable whether or not it applies to the somewhat more concentrated coal suspensions required for the present project. Therefore, to determine the law`s applicability, a series of turbidity measurements was conducted on particle suspensions which varied in particle concentration over a wide range, and the results were analyzed to see how well they agreed with the law. To determine the effect of air in promoting the oil agglomeration of coal particles in an aqueous suspension, a number of agglomeration tests were conducted with the model mixing system. Finely ground Pittsburgh No. 8 coal was used for these tests, and the amount of air present was controlled carefully. The agglomeration process was monitored by observing the change in turbidity of the system.

Wheelock, T.D.; Drzymala, J.; Zhang, F.; Nelson, C.

1994-09-01

23

Gas-hydrate formation, agglomeration and inhibition in oil-based drilling fluids for deep-water drilling  

Microsoft Academic Search

One of the main challenges in deep-water drilling is gas-hydrate plugs, which make the drilling unsafe. Some oil-based drilling fluids (OBDF) that would be used for deep-water drilling in the South China Sea were tested to investigate the characteristics of gas-hydrate formation, agglomeration and inhibition by an experimental system under the temperature of 4 °C and pressure of 20 MPa,

Fulong Ning; Ling Zhang; Yunzhong Tu; Guosheng Jiang; Maoyong Shi

2010-01-01

24

Technique for tertiary oil recovery  

SciTech Connect

The optimal salinity of an emulsifier system comprising an alcohol and a neutralized oxidized solvent extracted oil can be controlled to match the salinity of the brine used in the tertiary oil recovery process by controlling the acid number of the solvent extracted oil during the oxidation procedure, controlling the extent of the neutralization during neutralization of the oxidized solvent extracted oil, or both.

Alford, H.E.; Chan, K.S.

1982-05-11

25

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

SciTech Connect

Three major topics are discussed in this report: (1) Upgrading of Low Rank Coals by the Agflotherm Process. Test data, procedures, equipment, etc., are described for co-upgrading of subbituminous coals and heavy oil; (2) Upgrading of Bituminous Coals by the Agflotherm Process. Experimental procedures and data, bench and pilot scale equipments, etc., for beneficiating bituminous coals are described; (3) Soil Clean-up and Hydrocarbon Waste Treatment Process. Batch and pilot plant tests are described for soil contaminated by tar refuse from manufactured gas plant sites. (VC)

Ignasiak, B.; Ignasiak, T.; Szymocha, K.

1990-01-01

26

Unstructured multigrid through agglomeration  

NASA Technical Reports Server (NTRS)

In this work the compressible Euler equations are solved using finite volume techniques on unstructured grids. The spatial discretization employs a central difference approximation augmented by dissipative terms. Temporal discretization is done using a multistage Runge-Kutta scheme. A multigrid technique is used to accelerate convergence to steady state. The coarse grids are derived directly from the given fine grid through agglomeration of the control volumes. This agglomeration is accomplished by using a greedy-type algorithm and is done in such a way that the load, which is proportional to the number of edges, goes down by nearly a factor of 4 when moving from a fine to a coarse grid. The agglomeration algorithm has been implemented and the grids have been tested in a multigrid code. An area-weighted restriction is applied when moving from fine to coarse grids while a trivial injection is used for prolongation. Across a range of geometries and flows, it is shown that the agglomeration multigrid scheme compares very favorably with an unstructured multigrid algorithm that makes use of independent coarse meshes, both in terms of convergence and elapsed times.

Venkatakrishnan, V.; Mavriplis, D. J.; Berger, M. J.

1993-01-01

27

Fuel agglomerates and method of agglomeration  

SciTech Connect

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. 1 fig., 7 tabs.

Wen, W.W.

1985-08-09

28

POC-scale testing of oil agglomeration techniques and equipment for fine coal processing  

SciTech Connect

The information presented in this manual is solely for the purpose of operating the POC-scale equipment for fine coal processing as described herein. This manual provides a general description of the process technology and guidelines for plant operating procedures. It is intended for use by the operators and maintenance personnel who will be responsible for the operations of the plant. No attempt should be made to operate the plant until the principles of the process and operating instructions contained in this manual are fully understood. Operating personnel should thoroughly familiarize themselves with all processing equipment prior to commencing plant operation. All equipment is skid mounted to provide a self-contained unit. The dimensions of the unit are comply with standard guidelines. A minimum distance of 2 feet is provided between equipment for walkway and maintenance.

W. Pawlak; K. Szymocha

1999-07-01

29

Spatio-temporal variability of surface water quality of fresh water resources in Ranchi Urban Agglomeration, India using geospatial techniques  

NASA Astrophysics Data System (ADS)

Study was conducted in Ranchi Urban Agglomeration (RUA) to assess the surface water quality of major rivers and reservoirs during pre- and post-monsoon periods. Study indicated increase in chemical contaminants and decrease in biological contaminants during monsoon periods and a positive correlation with built-up land within the catchment of surface water sources. The remote sensing-based approach indicated Swarnrekha river and tributaries as more encroached by built-up land (0.73 km2 within 50 m buffer) than Jumar river and its tributaries (0.21 km2). For the proper management of the surface water sources in RUA, government attention and interventions are required to minimize the contamination and safeguard the health of local residents.

Pandey, Arvind Chandra; Kumar, Amit

2014-03-01

30

Multidimensional nature of fluidized nanoparticle agglomerates.  

PubMed

We show that fluidized nanoparticle agglomerates are hierarchical fractal structures with three fractal dimensions: one characterizing sintered aggregates formed during nanoparticle synthesis, one that is also found in stored agglomerates and represents unbroken agglomerates, and one describing the large agglomerates broken during fluidization. This has been possible by using spin-echo small-angle neutron scattering-a relatively novel technique that, for the first time, allowed to characterize in situ the structure of fluidized nanoparticle agglomerates from 21 nm to ?20 ?m. The results show that serial agglomeration mechanisms in the gas phase can generate nanoparticle clusters with different fractal dimensions, contradicting the common approach that considers fluidized nanoparticle agglomerates as single fractals, in analogy to the agglomerates formed by micron-sized particles. This work has important implications for the fluidization field but also has a wider impact. Current studies deal with the formation and properties of clusters where the building blocks are particles and the structure can be characterized by only one fractal dimension. However, fluidized nanoparticle agglomerates are low-dimensional clusters formed by higher-dimensional clusters that are formed by low-dimensional clusters. This multifractality demands a new type of multiscale model able to capture the interplay between different scales. PMID:25313446

de Martín, Lilian; Bouwman, Wim G; van Ommen, J Ruud

2014-10-28

31

Remediation of Sucarnoochee soil by agglomeration with fine coal  

SciTech Connect

Fine-sized Blue Creek coal was used to remove high molecular weight hydrocarbons from Sucarnoochee soil, a fine-sized high-organic soil. Fine coal in slurry form was blended with Sucarnoochee soil contaminated with 15.0% by wt of crude oil, and agglomerates were removed in a standard flotation cell. Crude oil in the remediated soil was reduced from the original 15.0% to less than a tenth of a wt% by a two-step process. Oil removal of approx. 99.3% was obtained. An added benefit was that the low-grade coal used in the process was simultaneously upgraded. The final level of cleaning was not affected by initial oil concentration. The process compared favorably with a hot water wash technique used to recovery oils from contaminated soil.

Narayanan, P.S.; Arnold, D.W.; Rahnama, M.B. (Univ. of Alabama, Tuscaloosa, AL (United States))

1994-01-01

32

Fuel agglomerates and method of agglomeration  

SciTech Connect

A method is described of producing water-resistant carbonaceous agglomerates suitable for use as a fuel comprising: providing a solid, oxidized carbonaceous material including chemically combined oxygen as humic acid or humate salt; extracting humates from the oxidized material into aqueous alkali solution to form a binder solution; providing particulate carbonaceous fuel material having a heating value greater than that of the oxidized carbonaceous material; blending the binder solution in mixture with the particulate fuel to permeate the humate solute into the fuel particles; consolidating the particulate fuel into agglomerates of convenient size for fuel use; and drying the agglomerates to reduce moisture content and convert the humate solute into a solid, water-resistant binder material throughout the agglomerate.

Wen, W.W.

1986-10-07

33

Evaluating oil spill control equipment and techniques  

Microsoft Academic Search

Shell Oil Co. has initiated a program to develop formal oil-spill action plans to handle the increasing spill incidence. Shell constructed a 120 x 50 x 5-ft wave tank equipped with a mechanical wave generator to conduct tests using 3 variables: (1) environmental condition; (2) volume of oil spilled; and (3) type of oil spilled. The environmental conditions imposed were

Milz

1970-01-01

34

Separating oil from oil-water emulsions by electroflotation technique  

Microsoft Academic Search

The separation of finely dispersed oil from oil-water emulsions was carried out in an electroflotation cell which has a set of electrodes, a lead anode and stainless steel screen cathode. The effect of operating parameters on the performance of the batch cell was examined. The parameters investigated are electrical current, oil concentration, flotation time and flocculant agent concentrations. A well-fitted

Ashraf Y. Hosny

1996-01-01

35

Development and Application of Agglomerated Multigrid Methods for Complex Geometries  

NASA Technical Reports Server (NTRS)

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.

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

2010-01-01

36

New technique for oil backstreaming contamination measurements  

NASA Technical Reports Server (NTRS)

Due to the large size and the number of diffusion pumps, space simulation chambers cannot be easily calibrated by the usual test dome method for measuring backstreaming from oil diffusion pumps. In addition, location dependent contamination may be an important parameter of the test. The backstreaming contamination in the Space Power Facility (SPF) near Sandusky, Ohio, the largest space simulation vacuum test chamber in the U.S.A. was measured. Small size clean silicon wafers as contamination sensors placed at all desired measurement sites were used. The facility used diffusion pumps with DC 705 oil. The thickness of the contamination oil film was measured using ellipsometry. Since the oil did not wet uniformly the silicon substrate, two analysis models were developed to measure the oil film: continuous, homogeneous film and islands of oil with the islands varying in coverage fraction and height. In both cases, the contamination film refractive index was assumed to be that of DC 705. The second model improved the ellipsometric analysis quality parameter by up to two orders of magnitude, especially for the low coverage cases. Comparison of the two models for our case shows that the continuous film model overestimates the oil volume by less than 50 percent. Absolute numbers for backstreaming are in good agreement with published results for diffusion pumps. Good agreement was also found between the ellipsometric results and measurements done by x ray photoelectron spectroscopy (XPS) and by scanning electron microscopy (SEM) on samples exposed to the same vacuum runs.

Alterovitz, S. A.; Speier, H. J.; Sieg, R. M.; Drotos, M. N.; Dunning, J. E.

1993-01-01

37

TECHNIQUES FOR MIXING DISPERSANTS WITH SPILLED OIL  

EPA Science Inventory

The effective use of some oil spill dispersants requires the addition of mixing energy to the dispersant-treated slick. Various methods of energy application have included the use of fire hose streams directed to the water surface, outboard motors mounted on work boats, and the f...

38

Micro-agglomerate flotation for deep cleaning of coal  

SciTech Connect

We are investigating the use of a hybrid process - Micro-agglomerate flotation - which is a combination of oil-agglomeration and froth flotation. The basic concept is to use small quantities of oil to promote the formation of dense micro-agglomerates with minimal entrapment of water and mineral particles, and to use froth flotation to extract these micro-agglomerates from the water/dispersed-mineral phase. Since the floating units are agglomerates (about 30--50 [mu]m in size) rather than individual coal particles (1--10 [mu]m) the problems of froth overload and water/mineral carryover should be significantly alleviated. Micro-agglomerate flotation has considerable potential for the practical deep cleaning of coal on a commercial scale. In principle, it should be possible to achieve both high selectivity and high yield at reasonable cost. The process requires only conventional, off-the-shelf equipment and reagent usage (oil, surfactants, etc.) should be small. There are, however, complications. The process involves at least five phases: two or more solids (coal and mineral), two liquids (oil and water) and one gas (air). It is necessary to maintain precise control over the chemistry of the liquid phases in order to promote the interfacial reactions and interactions between phases necessary to ensure selectivity. Kinetics as well as thermodynamic factors may be critical in determining overall system response.

Chander, S.; Hogg, R.

1993-01-01

39

Modelling of agglomeration in suspension: Application to salicylic acid microparticles  

Microsoft Academic Search

The agglomeration in suspension technique consists of adding directly into the suspension a small amount of a second liquid which acts as an interparticle bonding agent. The system (salicylic acid particles, aqueous solution, chloroform) is studied experimentally by in situ image analysis. After a brief period of wetting of the particles by the binding liquid, the agglomerates grow by a

A. F. Blandin; D. Mangin; C. Subero-Couroyer; A. Rivoire; J. P. Klein; J. M. Bossoutrot

2005-01-01

40

Cottonseed oil estimation by pulsed nuclear magnetic resonance technique  

Microsoft Academic Search

Seed asymmetry and moisture associated with the seeds are known to affect seed oil estimation by pulsed nuclear magnetic resonance\\u000a (NMR) technique employing free induction decay or single spin echo (SE) pulse sequence. UsingGossypium (cottonseeds) as experimental material, it is shown that transverse relaxation times (T2) of seed oil, in different varieties of seeds, measured in vivo, are not the

V. T. Srinivasan; B. B. Singh; P. K. Chidambareswaran; V. Sundaram

1985-01-01

41

Proper Oil Sampling Intervals and Sample Collection Techniques Gasoline/Diesel/Natural Gas Engines  

E-print Network

Proper Oil Sampling Intervals and Sample Collection Techniques Gasoline/Diesel/Natural Gas Engines: � Oil samples can be collected during oil changes. Follow manufacturers recommendations on frequency (hours, mileage, etc) of oil changes. � Capture a sample from the draining oil while the oil is still hot

42

Micromechanics of agglomerate damage processes.  

E-print Network

??This thesis reports a detailed investigation of the micromechanics of agglomerate behaviour under free-fall impact, double (punch) impact and diametrical compression tests using the simulation… (more)

Ciomocos, M.T.

1996-01-01

43

Thermal Characterization of Edible Oils by Using Photopyroelectric Technique  

NASA Astrophysics Data System (ADS)

Thermal properties of several edible oils such as olive, sesame, and grape seed oils were obtained by using the photopyroelectric technique. The inverse photopyroelectric configuration was used in order to obtain the thermal effusivity of the oil samples. The theoretical equation for the photopyroelectric signal in this configuration, as a function of the incident light modulation frequency, was fitted to the experimental data in order to obtain the thermal effusivity of these samples. Also, the back photopyroelectric configuration was used to obtain the thermal diffusivity of these oils; this thermal parameter was obtained by fitting the theoretical equation for this configuration, as a function of the sample thickness (called the thermal wave resonator cavity), to the experimental data. All measurements were done at room temperature. A complete thermal characterization of these edible oils was achieved by the relationship between the obtained thermal diffusivities and thermal effusivities with their thermal conductivities and volumetric heat capacities. The obtained results are in agreement with the thermal properties reported for the case of the olive oil.

Lara-Hernández, G.; Suaste-Gómez, E.; Cruz-Orea, A.; Mendoza-Alvarez, J. G.; Sánchez-Sinéncio, F.; Valcárcel, J. P.; García-Quiroz, A.

2013-05-01

44

Geography, Industrial Organization, and Agglomeration  

Microsoft Academic Search

This paper makes two contributions to the empirical literature on agglomeration economies. First, the paper uses a unique and rich database in conjunction with mapping software to measure the geographic extent of agglomerative externalities. Previous papers have been forced to assume that agglomeration economies are club goods that operate at a metropolitan scale. Second, the paper tests for the existence

Stuart S. Rosenthal; William C. Strange

2003-01-01

45

Investigation of melt agglomeration process with a hydrophobic binder in combination with sucrose stearate  

Microsoft Academic Search

The melt agglomeration process of lactose powder with hydrogenated cottonseed oil (HCO) as the hydrophobic meltable binder was investigated by studying the physicochemical properties of molten HCO modified by sucrose stearates S170, S770 and S1570. The size, size distribution, micromeritic and adhesion properties of agglomerates as well as surface tension, contact angle, viscosity and specific volume of molten HCO, with

Paul Wan Sia Heng; Tin Wui Wong; Wai See Cheong

2003-01-01

46

Separation of oil-water-sludge emulsions coming from palm oil mill process through microwave techniques.  

PubMed

The palm oil mills extraction process requires the separation of oil-water-sludge emulsions. For this purpose, the use of sedimentation and/or centrifugation techniques have been required until now. However, significant losses persist in different process flows and new methods are needed to further decrease them, such as methods based on electromagnetic waves application. In the study, emulsions obtained from two flow processes, namely press liquor stream (PL) and recovered stream of the centrifugal step (RC), were exposed to microwave radiation with different exposure times. In the case of the press liquor stream, different oil/water dilution ratios were also studied. The sedimentation speed and efficiency were studied for the irradiated samples and compared to those obtained for the same fluids with no radiation. Also, chromatographic tests were performed on the recovered oil to determine the effect on the oil quality after microwave radiation. The obtained results allow us to conclude that microwave exposure during periods below 1 minute lead to better sedimentation speed and efficiency. It was observed that microwaves facilitate the break of the charges and polarities balances in the emulsions at considerably lower temperatures than the corresponding in the conventional process, without affecting the recovered oil quality. PMID:19227069

Pérez-Páez, Rocío; Catalá-Civera, José Manuel; García-Baños, Beatriz; Castillo, Edgar F; Bastos, Johanna M; Zambrano, Luz S

2008-01-01

47

Hydrophobic Agglomeration of Mineral Fines in Aqueous Suspensions and its Application in Flotation: a Review  

NASA Astrophysics Data System (ADS)

Hydrophobic agglomeration is originated from the hydrophobic attraction between particles, which is essentially different from electrolyte coagulation and polymer flocculation. It is applied to mineral processing in floc-flotation process to improve the recovery of mineral fines. In this paper, the applications of this phenomenon in mineral fines were summarized, including the origin of hydrophobic agglomeration, the main factors affect hydrophobic agglomeration (particle hydrophobicity, shear rate and duration, nonpolar oil and tank geometry), as well as hydrophobic agglomeration based separation processes (carrier flotation and floc-flotation).

Yang, Bingqiao; Song, Shaoxian

2014-05-01

48

Microbial effects on colloidal agglomeration  

SciTech Connect

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 to 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.

Hersman, L.

1995-11-01

49

Similarity considerations for acoustic agglomeration  

NASA Astrophysics Data System (ADS)

Acoustic agglomerators work, not only in reducing the total number concentration but also to effectively shift the size distribution to a larger size range depending on the frequency and intensity applied to the particular particle size distribution. The acoustic agglomerator is like any other conventional particulate abatement device from the viewpoint, that the design, materials and construction are dictated solely for that particular application and given system conditions. In addition, the acoustic agglomerator has to be tuned to that specific application for best results. In spite of the low efficiencies of sound generators, the total energy consumption is small, rapidly increasing at the higher sound intensity levels where turbulence dominates, wherein the amount of useful energy for agglomeration is smaller relative to the input acoustic energy, although it is counter benefitted by the increase in the rate of agglomeration and removal. Thus it is the availability of space and costs which inherently decides the rates of agglomeration and removal which indirectly determines the intensity levels to be used.

Patel, S.; Shaw, D. T.

1980-06-01

50

Development and scale-up of particle agglomeration processes for coal beneficiation  

NASA Astrophysics Data System (ADS)

The development of two modified agglomeration processes for coal beneficiation is presented separately in Parts I and II of this dissertation. Part I is based on research which was conducted to study the mechanism and characteristics of a gas-promoted oil agglomeration process. Part II is based on research which was carried out to develop a newer and more innovative method for agglomerating coal particles with microscopic gas bubbles in aqueous suspensions. In Part I, the development of a gas-promoted oil agglomeration process for cleaning coal was carried out with scale model mixing systems in which aqueous suspensions of ultrafine coal particles were treated with a liquid hydrocarbon and a small amount of air. The resulting agglomerates were recovered by screening. During batch agglomeration tests the progress of agglomeration was monitored by observing changes in agitator torque in the case of concentrated suspension. A key parameter turned out to be the minimum time te required to produce compact spherical agglomerates. Other important parameters included the projected area mean particle diameter of the agglomerates recovered at the end of a test as well as the ash content and yield of agglomerates. Batch agglomeration tests were conducted with geometrically similar mixing tanks which ranged in volume from 0.346 to 11.07 liters. It was shown that gas bubbles trigger the process of agglomeration and participate in a very complex mechanism involving the interaction of particles, oil droplets, and gas bubbles. The process takes place in stages involving dispersion of oil and gas, flocculation, coagulation, and agglomerate building. Numerous agglomeration tests were conducted with two kinds of coal in concentrated suspensions to determine the important characteristics of the process and to study the effects of the following operating parameters: i-octane concentration, air concentration, particle concentration, tank diameter, impeller diameter, and impeller speed. Several excellent correlations between the minimum time required to produce spherical agglomerates or a final agglomerate diameter and the operating parameters were obtained by using the general linear regression method. In addition, the results provided a basis for size scale up of an agglomeration system. In Part II, the technical feasibility of a gas agglomeration method for cleaning coal was demonstrated by means of bench-scale tests conducted with a mixing system which enabled the treatment of ultrafine coal particles with a colloidal suspension of microscopic gas bubbles in water. A suitable suspension of microbubbles was produced by agitation and a small amount of i-octane. When the suspension of microbubbles and coal particles was mixed, agglomeration was rapid and small spherical agglomerates were produced. Since the agglomerates floated, they were separated from the nonfloating tailings in a settling chamber. By employing this method in numerous agglomeration tests of moderately hydrophobic coals with 26 wt. % ash, it was shown that the ash content could be reduced to 6--7 wt. % while achieving a coal recovery of 75 to 85% on a dry, ash-free basis by using a solids concentration of 3 to 5 w/w %, air saturation of 5 to 15 psig, and i-octane concentration of 1.0 v/w % based on the coal weight. It was also shown that the process of agglomeration can be reversed by subjecting an aqueous suspension of agglomerates to a pressure sufficient to redissolve the microbubbles.

Shen, Meiyu

51

Application of thermal analytical techniques to enhanced oil recovery  

Microsoft Academic Search

The thermal process is most suitable for recovery of heavy oils and oil sand bitumens. In this process oil displacement results from: viscosity reduction primarily due to heat and secondly due to carbon dioxide dissolution in oil, thermal expansion of the oil resulting in increased relative permeability, distillation and thermal cracking of oil, a solution gas drive from produced gas

Jha

1983-01-01

52

Remediation of Sucarnoochee soil by agglomeration with fine coal  

Microsoft Academic Search

Fine-sized Blue Creek coal was used to remove high molecular weight hydrocarbons from Sucarnoochee soil, a fine-sized high-organic soil. Fine coal in slurry form was blended with Sucarnoochee soil contaminated with 15.0% by wt of crude oil, and agglomerates were removed in a standard flotation cell. Crude oil in the remediated soil was reduced from the original 15.0% to less

P. S. Narayanan; D. W. Arnold; M. B. Rahnama

1994-01-01

53

Flocculation, hydrophobic agglomeration and filtration of ultrafine coal  

NASA Astrophysics Data System (ADS)

In coal preparation plant circuits, fine coal particles are aggregated either by oil agglomeration or by flocculation. In a new hydrophobic agglomeration process, recently developed hydrophobic latices are utilized. While the selectivity of such aggregation processes determines the beneficiation results, the degree of aggregation has a strong effect on fine coal filtration. The aim of this research was to study the fundamentals and analyze the common grounds for these processes, including the potential effect of the coal surface properties. The selective flocculation tests, in which three types of coal, which differed widely in surface wettability, and three additives (hydrophobic latices, a semi-hydrophobic flocculant and a typical hydrophilic polyelectrolyte) were utilized, showed that coal wettability plays a very important role in selective flocculation. The abstraction of a hydrophobic latex on coal and silica revealed that the latex had a much higher affinity towards hydrophobic coal than to hydrophilic mineral matter. As a result, the UBC-1 hydrophobic latex flocculated only hydrophobic coal particles while the polyelectrolyte (PAM) flocculated all the tested coal samples and minerals, showing no selectivity in the fine coal beneficiation. The oil agglomeration was tested using kerosene emulsified with various surfactants (e.g. cationic, anionic and non-ionic). Surfactants enhance not only oil emulsification, hence reducing oil consumption (down to 0.25--0.5%), but also entirely change the electrokinetic properties of the droplets and affect the interaction energy between oil droplets and coal particles. Consequently, the results found in the course of the experimental work strongly indicate that even oxidized coals can be agglomerated if cationic surfactants are used to emulsify the oil. Oil agglomeration of the Ford-4 ultrafine coal showed that even at extremely low oil consumption (0.25 to 0.5%), a clean coal product with an ash content around 5% at over 99.9% coal recovery could be obtained in a one-stage separation by screening the agglomerated product. If a conventional oil agglomeration process is used instead, oil consumption as high as 30% is needed to obtain comparable results. In the tests on filtration and dewatering of ultrafine and fine coals, the effect of chemical additives and coal surface properties was investigated. The tests revealed very significant differences in the filtration of ultrafine (-45 mum) and fine (-500 mum) coals. The moisture contents in the filter cakes in the tests with ultrafine coal were around 40% (irrespective of the coal surface properties), while for the fine coal the moisture content fluctuated around 18% (Ford-4) and 30% (Ford-13). The results revealed that the hydrophobic latex and the emulsified oils could not only successfully beneficiate the ultrafine coal but also significantly increase filtration rate and/or reduce moisture content of the filter cake. Among the chemicals tested, the emulsified oils were found to be the most promising not only for the beneficiation but also for filtration and dewatering processes. Surfactants were found to only slightly affect the filtration of fine coal. However, they can influence filtration very profoundly if utilized to emulsify the oil which is used to agglomerate coal prior to its filtration.

Yu, Zhimin

54

A new approach to examining scorpion peg sensilla: the mineral oil flood technique  

E-print Network

A new approach to examining scorpion peg sensilla: the mineral oil flood technique Elizabeth D approach to examining scorpion peg sensilla: the mineral oil flood technique Elizabeth D. Knowlton of a polar, liquid substance while recording electrophysiologically under mineral oil. In this study, we

Gaffin, Doug

55

COAL CLEANING BY GAS AGGLOMERATION  

SciTech Connect

The agglomeration of ultrafine-size coal particles in an aqueous suspension by means of microscopic gas bubbles was demonstrated in numerous experiments with a scale model mixing system. Coal samples from both the Pittsburgh No. 8 Seam and the Upper Freeport Seam were used for these experiments. A small amount of i-octane was added to facilitate the process. Microscopic gas bubbles were generated by saturating the water used for suspending coal particles with gas under pressure and then reducing the pressure. Microagglomerates were produced which appeared to consist of gas bubbles encapsulated in coal particles. Since dilute particle suspensions were employed, it was possible to monitor the progress of agglomeration by observing changes in turbidity. By such means it became apparent that the rate of agglomeration depends on the concentration of microscopic gas bubbles and to a lesser extent on the concentration of i-octane. Similar results were obtained with both Pittsburgh No. 8 coal and Upper Freeport coal.

MEIYU SHEN; ROYCE ABBOTT; T.D. WHEELOCK

1998-09-30

56

Fractal Agglomerates in Nuclear Wastes  

NASA Astrophysics Data System (ADS)

Millions of gallons of radioactive wastes stored at Department of Energy sites need to be converted into stable waste forms for long term disposal. Unfortunately, many of the wastes contain colloidal sludges that can interfere with retrieval, transport, separation, and solidification procedures. The ability to predict and control the behavior of sludge suspensions during processing requires understanding what types of particles are present and how particle agglomeration influences slurry properties. Transmission electron microscopy shows that the sludge consists of agglomerates of submicron particles. The TEM images, combined with concepts of fractal geometry and the role of interparticle forces in mediating agglomerate structures, have been used to rationalize the orders of magnitude changes in slurry viscosity and sedimentation observed for both simulants and actual tank wastes.

Bunker, B. C.; Graff, G. L.; Keefer, K. D.; Liu, J.; Rector, D. R.; Smith, P. A.; Tingey, J. M.

1998-03-01

57

Air agglomeration of hydrophobic particles  

SciTech Connect

The agglomeration of hydrophobic particles in an aqueous suspension was accomplished by introducing small amounts of air into the suspension while it was agitated vigorously. The extent of aggregation was proportional both to the air to solids ratio and to the hydrophobicity of the solids. For a given air/solids ratio, the extent of aggregation of different materials increased in the following order: graphite, gilsonite, coal coated with heptane, and Teflon. The structure of agglomerates produced from coarse Teflon particles differed noticeably from the structure of bubble-particle aggregates produced from smaller, less hydrophobic particles.

Drzymala, J.; Wheelock, T.D.

1995-12-31

58

Agglomeration, Integration and Tax Harmonization  

Microsoft Academic Search

This paper considers tax competition and tax harmonization in the presence of agglomeration forces and falling trade costs. With agglomerative forces operating, industry is not indifferent to location in equilibrium, so perfectly mobile capital becomes a quasi-fixed factor. This suggests that the tax game is something subtler than a race to the bottom. Advanced 'core' nations may act like limit-pricing

2001-01-01

59

Agglomeration, Integration and Tax Harmonization  

Microsoft Academic Search

This Paper considers tax competition and tax harmonization in the presence of agglomeration forces and falling trade costs. With agglomerative forces operating, industry is not indifferent to location in equilibrium, so perfectly mobile capital becomes a quasi-fixed factor. This suggests that the tax game is something subtler than a race to the bottom. Advanced 'core' nations may act like limit-pricing

Richard E. Baldwin; Paul Krugman

2000-01-01

60

Demographic change, growth and agglomeration  

Microsoft Academic Search

This article presents a framework within which the effects of demographic change on both agglomeration and growth of economic activities can be analyzed. I introduce an overlapping generation structure into a New Economic Geography model with endogenous growth due to learning spillovers and focus on the effects of demographic structures on long-run equilibrium outcomes and stability properties. First, life-time uncertainty

Theresa Grafeneder-Weissteiner

2010-01-01

61

A Critical Study of Agglomerated Multigrid Methods for Diffusion  

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

62

A Critical Study of Agglomerated Multigrid Methods for Diffusion  

NASA Technical Reports Server (NTRS)

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.

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

2009-01-01

63

Agglomerate behaviour of fluticasone propionate within dry powder inhaler formulations.  

PubMed

Due to their small size, the respirable drug particles tend to form agglomerates which prevent flowing and aerosolisation. A carrier is used to be mixed with drug in one hand to facilitate the powder flow during manufacturing, in other hand to help the fluidisation upon patient inhalation. Depending on drug concentration, drug agglomerates can be formed in the mixture. The aim of this work was to study the agglomeration behaviour of fluticasone propionate (FP) within interactive mixtures for inhalation. The agglomerate phenomenon of fluticasone propionate after mixing with different fractions of lactose without fine particles of lactose (smaller than 32 ?m) was demonstrated by the optical microscopy observation. A technique measuring the FP size in the mixture was developed, based on laser diffraction method. The FP agglomerate sizes were found to be in a linear correlation with the pore size of the carrier powder bed (R(2)=0.9382). The latter depends on the particle size distribution of carrier. This founding can explain the role of carrier size in de-agglomeration of drug particles in the mixture. Furthermore, it gives more structural information of interactive mixture for inhalation that can be used in the investigation of aerosolisation mechanism of powder. According to the manufacturing history, different batches of FP show different agglomeration intensities which can be detected by Spraytec, a new laser diffraction method for measuring aerodynamic size. After mixing with a carrier, Lactohale LH200, the most cohesive batch of FP, generates a lower fine particle fraction. It can be explained by the fact that agglomerates of fluticasone propionate with very large size was detected in the mixtures. By using silica-gel beads as ball-milling agent during the mixing process, the FP agglomerate size decreases accordingly to the quantity of mixing aid. The homogeneity and the aerodynamic performance of the mixtures are improved. The mixing aid based on ball-milling effect could be used to ameliorate the quality of inhalation mixture of cohesive drug, such as fluticasone propionate. However, there is a threshold where an optimal amount of mixing aids should be used. Not only the drug des-aggregation reaches its peak but the increase in drug-carrier adhesion due to high energy input should balance the de-agglomeration capacity of mixing process. This approach provides a potential alternative in DPI formulation processing. PMID:22198291

Le, V N P; Robins, E; Flament, M P

2012-04-01

64

Application of microbial enhanced oil recovery technique to a Turkish heavy oil  

Microsoft Academic Search

Microbial enhance oil recovery utilizes microorganisms and their metabolic products to improve the recovery of crude oil from reservoir rocks. In this study an anaerobic bacterium, Clostridium acetobutylicum was injected into a one-dimensional model reservoir containing a Turkish heavy oil (Raman oil) at 38° C. This injection was followed by water flooding after a suitable shut-in period. Comparison of oil

Kemal Behlulgil; Tanju Mehmetoglu; Sedat Donmez

1992-01-01

65

Human Capital, Talent, Agglomeration and Regional Growth  

Microsoft Academic Search

This paper is an introductory overview highlighting some of the current knowledge as regards three critical questions related to the emerging knowledge economy: i) Why does human capital and talent tend to agglomerate in large urban regions?, ii) How does this agglomeration affect the location of different types of economic activities?, and iii) How does this agglomeration affect regional growth?

Charlie Karlsson; Börje Johansson; Roger R. Stough

2009-01-01

66

Oblique impact simulations of high strength agglomerates  

Microsoft Academic Search

Different types of particle compounds like concrete particles can be considered as a model material of high strength agglomerates. It is necessary to investigate and understand fracture behaviour of these agglomerates in order to avoid breakage during storage, handling and transportation. The aim of the research is to examine the comminution behaviour of high strength agglomerates during oblique impact loadings.A

Manoj Khanal; Jürgen Tomas

2009-01-01

67

Coal Beneficiation by Gas Agglomeration  

SciTech Connect

Coal beneficiation is achieved by suspending coal fines in a colloidal suspension of microscopic gas bubbles in water under atmospheric conditions to form small agglomerates of the fines adhered by the gas bubbles. The agglomerates are separated, recovered and resuspended in water. Thereafter, the pressure on the suspension is increased above atmospheric to deagglomerate, since the gas bubbles are then re-dissolved in the water. During the deagglomeration step, the mineral matter is dispersed, and when the pressure is released, the coal portion of the deagglomerated gas-saturated water mixture reagglomerates, with the small bubbles now coming out of the solution. The reagglomerate can then be separated to provide purified coal fines without the mineral matter.

Thomas D. Wheelock; Meiyu Shen

2000-03-15

68

Numerical simulations of diametrical compression tests on agglomerates  

Microsoft Academic Search

The paper reports discrete element simulations of the diametrical compression test applied to two spherical agglomerates: one a dense agglomerate and the other a loosely packed agglomerate. The results obtained for the dense agglomerate show that the agglomerate fractures along a slightly inclined, approximately diametrical plane. Outwardly, the agglomerate shows all the characteristics of brittle fracture but half of the

C Thornton; M. T Ciomocos; M. J Adams

2004-01-01

69

Development of Extraction Techniques for the Detection of Signature Lipids from Oil  

SciTech Connect

Pure cultures, including Desulfovibrio vulgaris and Methanococcus maripaludus, were combined with model oil samples and oil/diesel mixtures to optimize extraction techniques of signature lipids from oil in support of investigation of microbial communities in oil deposit samples targets for microbial enhanced hydrocarbon recovery. Several techniques were evaluated, including standard phospholipid extraction, ether linked lipid for Archaeal bacterial detection, and high pressure extractiontechniques. Recovery of lipids ranged from 50-80percent as compared to extraction of the pure culture. Extraction efficiency was evaluated by the use of internal standards. Field samples will also be tested for recovery of signature lipids with optimized extraction techniques.

Borglin, Sharon; Geller, Jil; Chakraborty, Romy; Hazen, Terry; Mason, Olivia

2010-05-17

70

An analysis of oil and gas supply modeling techniques and a survey of offshore supply models  

SciTech Connect

This report surveys the literature on empirical oil and gas supply modeling techniques. These techniques are categorized as either geologic/engineering, econometric, or hybrid - the last being a combination of geologic and econometric techniques. The geologic/ engineering models are further disaggregated into play analysis models and discovery process models. The strengths and weaknesses of each of the models are discussed. The report concludes with a discussion of how these techniques have been applied to offshore oil and gas supply.

Walls, M.A.

1990-01-01

71

Application of petroleum hydrocarbon chemical fingerprinting and allocation techniques after the Exxon Valdez oil spill  

Microsoft Academic Search

Advances in environmental chemistry laboratory and data interpretation techniques (i.e. chemical fingerprinting) contributed to a better understanding of the biological impact of the 1989 Exxon Valdez oil spill and the fate of the spilled oil. A review of the evolution of petroleum chemical fingerprinting techniques is presented followed by a summarization of how new approaches were used to characterize and

Paul D. Boehm; Gregory S. Douglas; William A. Burns; Paul J. Mankiewicz; David S. Page; A. Edward Bence

1997-01-01

72

Application of microbial enhanced oil recovery technique to Daqing Oilfield  

Microsoft Academic Search

Pseudomonas aeruginosa (P-1) and its metabolic products (PIMP) of 10% could enhance the oil recovery in the model reservoir by 11.2% and also decrease injection pressure by 40.1%. Further, PIMP (10%) could reduce the crude oil viscosity by 38.5%. In the pilot tests, about 80% of wells used showed a significant increase in crude oil production after PIMP injection and

Qingxin Li; Congbao Kang; Hao Wang; Chunde Liu; Changkai Zhang

2002-01-01

73

Lubricant properties of Moringa oil using thermal and tribological techniques  

Microsoft Academic Search

The increasing application of biobased lubricants could significantly reduce environmental pollution and contribute to the\\u000a replacement of petroleum base oils. Vegetable oils are recognized as rapidly biodegradable and are thus promising candidates\\u000a for use as base fluids in formulation of environment friendly lubricants. Although many vegetable oils have excellent lubricity,\\u000a they often have poor oxidation and low temperature stability. Here

Brajendra K. Sharma; Umer Rashid; Farooq Anwar; Sevim Z. Erhan

2009-01-01

74

Chemical Influence on the Formation, Agglomeration, and Natural Transportability of Gas Hydrates. A Multivariate Component Analysis  

Microsoft Academic Search

This study has focused on chemical components in two paraffinic oil phases, expected to have an influence on the properties of gas hydrates regarding formation, agglomeration, and natural transportability. Crude oil, toluene, wax, and naphtenic acids were selected for this purpose. Two paraffinic phases were used; n?decane and Exxsol D?80, the latter containing surface active material. The experiments were performed

Linn Bergflødt; Lars Henrik Gjertsen; Johan Sjöblom; Harald Kallevik; Gisle Øye

2004-01-01

75

A new technique for oil backstreaming contamination measurements  

NASA Technical Reports Server (NTRS)

Due to the large size and the number of diffusion pumps, space simulation chambers cannot be easily calibrated by the usual test dome method for measuring backstreaming from oil diffusion pumps. In addition, location dependent contamination may be an important parameter of the test. The backstreaming contamination was measured in the Space Power Facility (SPF) near Sandusky, OH, the largest space simulation vacuum test chamber in the U.S.. Small clean silicon wafers placed at all desired measurement sites were used as contamination sensors. The facility used diffusion pumps with DC 705 oil. The thickness of the contamination oil film was measured using ellipsometry. Since the oil did not wet the silicon substrate uniformly, two analysis models were developed to measure the oil film: (1) continuous, homogeneous film; and (2) islands of oil with the islands varying in coverage fraction and height. In both cases, the contamination film refractive index was assumed to be that of DC 705. The second model improved the ellipsometric analysis quality parameter by up to two orders of magnitude, especially for the low coverage cases. Comparison of the two models shows that the continuous film model overestimates the oil volume by less than 50 percent. Absolute numbers for backstreaming are in good agreement with published results for diffusion pumps. Good agreement was also found between the ellipsometric results and measurements done by x-ray photoelectron spectroscopy (XPS) and by scanning electron microscopy (SEM) on examples exposed to the same vacuum runs.

Alterovitz, S. A.; Speier, H. J.; Sieg, R. M.; Drotos, M. N.; Dunning, J. E.

1991-01-01

76

[Bio-remediation techniques of crude oil contaminated soils].  

PubMed

The bioremediation of soils contaminated by different types of petroleum were carried out with composting process in a prepared bed. By the measures of nutrient- and microbiological agent addition, and moisture- and pH control, an ideal environment for microbes were obtained. When total petroleum hydrocarbons, which consist of thin oil, high condensation oil, special viscous oil, and viscous oil, were in the range of 25.8-77.2 g.kg-1 dry soil, the petroleum removal rate could reach 38.37-56.74% by 2 months operation. The contents of aromatic hydrocarbon, asphaltum and resin were important factors controlling the degradation of petroleum. 6 fungi, 6 bacteria and 1 actinomyces were found to be the dominant strains for petroleum degradation. The results could provide theoretical bases for remediation of soil contaminated by petroleum. PMID:12625007

Li, Peijun; Guo, Shuhai; Sun, Tieheng; Tai, Peidong; Zhang, Chungui; Bai, Yuxing; Sun, Qiang; Sheng, Ping

2002-11-01

77

Screening for antimicrobial activity of some essential oils by the agar overlay technique  

Microsoft Academic Search

Fifty-three essential oils were tested against five micro-organisms (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans) using the agar overlay technique. The essential oils were randomly selected and not on the basis of a supposed activity. It was found that all oils showed an activity against at least one micro-organism, and that substantial activities againstP. aeruginosa were scarce.

A. M. Janssen; N. L. J. Chin; J. J. C. Scheffer; A. Baerheim Svendsen

1986-01-01

78

Oil spill classification from multi-spectral satellite images: exploring different machine learning techniques  

Microsoft Academic Search

This work describes the potential of oil spill classification from optical satellite images, as investigated by applying different machine learning techniques to a dataset of more than 300 oil spill candidates, which have been detected from multi-spectral satellite sensors during the years 2008 and 2009, over the entire area of the Mediterranean Sea. A set of geometrical and grey level

Linda Corucci; Fabio Nardelli; Marco Cococcioni

2010-01-01

79

On the mechanism of agglomeration in suspension  

PubMed Central

Purpose: Agglomeration in suspension is a size enlargement method that facilitates operation of solid processing and preserves the solubilization properties of fine particles. A small quantity of binder liquid is added into a suspension of microparticles, directly in the stirred vessel where the precipitation or crystallization took place. This study deals with the evaluation of the effect of agitation time before and after addition of binder liquid on agglomerates properties in order to give some insights into the mechanism of the formation of the agglomerates. Methods: Carbamazepine is used as a model drug and isopropyl acetate is used as binder liquid. The agglomerates characterization includes the particle size, morphology and density. Results: The results showed that, by increasing the agitation time before addition of binder liquid, smaller agglomerates with less density and irregular forms composed of larger crystals were obtained. However, with increasing agitation time after addition of binder liquid the agglomerates size and density increases and morphology improves. Indeed, by continuing agitation along the course of agglomeration the properties of the particles change gradually but substantially. Conclusion: With optimized agitation time before and after addition of binder liquid, spherical and dense agglomerates can be obtained. PMID:24312767

maghsoodi, maryam; Derakhshandeh, Katayoun; Yari, Zahra

2012-01-01

80

Competition, agglomeration, and performance of Beijing hotels  

Microsoft Academic Search

Agglomeration theory argues that locating close to competitors can be beneficial in terms of gaining from heightened demand – more frequent consumer visits and subsequent purchases through reducing consumer search costs. This paper examines the trade-off between competition and the agglomeration effects of physical proximity in the Beijing hotel industry. It seeks to answer two questions: (1) What types of

Eric W. K. Tsang; Paul S. L. Yip

2009-01-01

81

Toward a Molecular Understanding of Crystal Agglomeration  

Microsoft Academic Search

A predictive model of the effect of crystal agglomeration on particle form and size distribution requires the quantification of various process parameters that depend on the microscopic properties of specific crystal faces and their interaction with the solvent. In this article, we discuss the various stages in the agglomeration process, using the results of recent experiments on breaking the agglomerative

Michael Brunsteiner; Alan G. Jones; Federica Pratola; Sarah L. Price; Stefaan J. R. Simons

2005-01-01

82

A technique for evaluating the oil/heavy-oil viscosity changes under ultrasound in a simulated porous medium.  

PubMed

Theoretically, Ultrasound method is an economical and environmentally friendly or "green" technology, which has been of interest for more than six decades for the purpose of enhancement of oil/heavy-oil production. However, in spite of many studies, questions about the effective mechanisms causing increase in oil recovery still existed. In addition, the majority of the mechanisms mentioned in the previous studies are theoretical or speculative. One of the changes that could be recognized in the fluid properties is viscosity reduction due to radiation of ultrasound waves. In this study, a technique was developed to investigate directly the effect of ultrasonic waves (different frequencies of 25, 40, 68 kHz and powers of 100, 250, 500 W) on viscosity changes of three types of oil (Paraffin oil, Synthetic oil, and Kerosene) and a Brine sample. The viscosity calculations in the smooth capillary tube were based on the mathematical models developed from the Poiseuille's equation. The experiments were carried out for uncontrolled and controlled temperature conditions. It was observed that the viscosity of all the liquids was decreased under ultrasound in all the experiments. This reduction was more significant for uncontrolled temperature condition cases. However, the reduction in viscosity under ultrasound was higher for lighter liquids compare to heavier ones. Pressure difference was diminished by decreasing in the fluid viscosity in all the cases which increases fluid flow ability, which in turn aids to higher oil recovery in enhanced oil recovery (EOR) operations. Higher ultrasound power showed higher liquid viscosity reduction in all the cases. Higher ultrasound frequency revealed higher and lower viscosity reduction for uncontrolled and controlled temperature condition experiments, respectively. In other words, the reduction in viscosity was inversely proportional to increasing the frequency in temperature controlled experiments. It was concluded that cavitation, heat generation, and viscosity reduction are three of the promising mechanisms causing increase in oil recovery under ultrasound. PMID:24075416

Hamidi, Hossein; Mohammadian, Erfan; Junin, Radzuan; Rafati, Roozbeh; Manan, Mohammad; Azdarpour, Amin; Junid, Mundzir

2014-02-01

83

Tests of absorbents and solidification techniques for oil wastes  

SciTech Connect

A representative of each of six classes of commonly used adsorbents was chosen for a series of tests. After reviewing ASTM and other related standard tests, uncomplicated procedures were developed for carrying out specific tests to determine absorbency for simulated oil waste and for water, under static and simulated transportation (repetitive shock) conditions. The tests were then applied to the six representative absorbents. Solidification tests were performed using these absorbents saturated with oil and loaded to 50% of saturation. The binders used were Portland I cement and Delaware Custom Material (DCM) cement shale silicate. Samples were checked for proper set, and the amounts of free liquid were measured. Another series of tests was performed on samples of simulated oil waste without absorbent, using Portland cement and DCM cement shale silicate. Samples were checked for proper set, free liquid was measured, and compressive strengths were determined. The state-of-the-art parameters were identified which satisfy NRC disposal criteria for solidified radioactive waste. The literature was reviewed for alternative methods of managing oil wastes. Conclusions are drawn on the relative utility of the various methods. 17 references, 3 tables.

Lin, M.; MacKenzie, D. R.

1983-11-01

84

Micro-agglomerate flotation for deep cleaning of coal. Quarterly progress report, 1 April--30 June 1994  

SciTech Connect

The authors are investigating the use of a hybrid process--Micro-agglomerate flotation--which is a combination of oil-agglomeration and froth flotation. The basic concepts is to use small quantities of oil to promote the formation of dense micro-agglomerates with minimal entrapment of water and mineral particles, and to use froth flotation to extract these micro-agglomerates from the water/dispersed-mineral phase. Since the floating units are agglomerates (about 30--50 {mu}m in size) rather than individual coal particles (1--10 {mu}m) the problems of froth overload water/mineral carryover should be significantly alleviated. The process involves at least five phases: two or more solids (coal and mineral), two liquids (oil and water) and one gas (air). It is necessary to maintain precise control over the chemistry of the liquid phases in order to promote the interfacial reactions and interactions between phases necessary to ensure selectivity. Kinetics as well as thermodynamic factors may be critical in determining overall system response. The research program has been organized into several specific tasks: Task 1, interfacial studies; Task 2, emulsification; Task 3, agglomerate growth and structure; and Task 4, agglomerate flotation. This report summarizes the status of Tasks 2, 3, and 4.

Chander, S.; Hogg, R.

1994-07-01

85

Engineering development of selective agglomeration. Final report  

SciTech Connect

This report presents the findings of the project entitled ``Engineering Development of Selective Agglomeration.`` The purpose is to develop selective agglomeration technology to a commercially acceptable level by 1993. Engineering development included bench-scale process development, component development adaptation or modification of existing unit operations, proof-of-concept (POC) module design, fabrication, testing, data evaluation, and conceptual design of a commercial facility. The information obtained during POC operation resulted in a technical and economic design base sufficient to support construction and operation of a commercial plant. Throughout this project performance targets for the engineering development of selective agglomeration process were to achieve 85% or greater Btu recovery at 85% or greater pyritic sulfur rejection (PSR). Additional objectives included producing a final clean-coal product with an ash content of 6% or less which is suitable for conventional coal handling systems. The selective agglomeration process, as applied to coal cleaning, is based on differences in the surface chemistry of coal and its associated impurities. Coal particles are hydrophobic (i.e., repel water) while the majority of its impurities are hydrophilic (i.e., stabilized in water). During selective agglomeration, a liquid (the agglomerant) that is immiscible with water is introduced into a coal-water slurry and agitated to disperse it in the slurry, thereby allowing it to come into contact with all particles in the slurry. The coal particles, due to their hydrophobic nature, are attracted to the agglomerant phase. The hydrophilic mineral impurities remain in the water phase. Continued agitation of the agglomerant-coated coal particles causes them to coalesce to form agglomerates. Once the agglomerates are formed, they are separated from the mineral matter-bearing aqueous phase by subsequent processing steps.

Not Available

1993-04-01

86

Micro-agglomerate flotation for deep cleaning of coal. Final report  

SciTech Connect

The development of practical technologies for the deep cleaning of coal has been seriously hampered by the problems of carrying out efficient coal/mineral separations at the very fine sizes (often finer than 10 {micro}m) needed to achieve adequate liberation of the mineral matter from the coal matrix. In this investigation a hybrid process--Micro-agglomerate flotation--which is a combination of oil-agglomeration and froth flotation was studied. The basic concept is to use small quantities of oil to promote the formation of dense micro-agglomerates with minimal entrapment of water and mineral particles and to use froth flotation to separate these micro-agglomerates from the water/dispersed-mineral phase. Since the floating units will be relatively large agglomerates (30--50 {micro}m in size) rather than fine coal particles (1--10 {micro}m) the problems of froth overload and water/mineral carryover should be significantly alleviated. There are, however, complications. The process involves at least five phases: two or more solids (coal and mineral), two liquids (oil and water) and one gas (air). It is demonstrated in this study that the process is very sensitive to fluctuations in operating parameters. It is necessary to maintain precise control over the chemistry of the liquid phases as well as the agitation conditions in order to promote selectivity. Both kinetics as well as thermodynamic factors play a critical role in determining overall system response.

Chander, S.; Hogg, R.

1997-01-15

87

Ignition technique for an in situ oil shale retort  

DOEpatents

A generally flat combustion zone is formed across the entire horizontal cross-section of a fragmented permeable mass of formation particles formed in an in situ oil shale retort. The flat combustion zone is formed by either sequentially igniting regions of the surface of the fragmented permeable mass at successively lower elevations or by igniting the entire surface of the fragmented permeable mass and controlling the rate of advance of various portions of the combustion zone.

Cha, Chang Y. (Golden, CO)

1983-01-01

88

Improved techniques for fluid diversion in oil recovery. Final report  

SciTech Connect

This three-year project had two technical objectives. The first objective was to compare the effectiveness of gels in fluid diversion (water shutoff) with those of other types of processes. Several different types of fluid-diversion processes were compared, including those using gels, foams, emulsions, particulates, and microorganisms. The ultimate goals of these comparisons were to (1) establish which of these processes are most effective in a given application and (2) determine whether aspects of one process can be combined with those of other processes to improve performance. Analyses and experiments were performed to verify which materials are the most effective in entering and blocking high-permeability zones. The second objective of the project was to identify the mechanisms by which materials (particularly gels) selectively reduce permeability to water more than to oil. A capacity to reduce water permeability much more than oil or gas permeability is critical to the success of gel treatments in production wells if zones cannot be isolated during gel placement. Topics covered in this report include (1) determination of gel properties in fractures, (2) investigation of schemes to optimize gel placement in fractured systems, (3) an investigation of why some polymers and gels can reduce water permeability more than oil permeability, (4) consideration of whether microorganisms and particulates can exhibit placement properties that are superior to those of gels, and (5) examination of when foams may show placement properties that are superior to those of gels.

Seright, R.

1996-01-01

89

Economic analysis of secondary and enhanced oil recovery techniques in Wyoming  

NASA Astrophysics Data System (ADS)

This dissertation primarily aims to theoretically analyze a firm's optimization of enhanced oil recovery (EOR) and carbon dioxide sequestration under different social policies and empirically analyze the firm's optimization of enhanced oil recovery. The final part of the dissertation empirically analyzes how geological factors and water injection management influence oil recovery. The first chapter builds a theoretical model to analyze economic optimization of EOR and geological carbon sequestration under different social policies. Specifically, it analyzes how social policies on sequestration influence the extent of oil operations, optimal oil production and CO2 sequestration. The theoretical results show that the socially optimal policy is a subsidy on the net CO2 sequestration, assuming negative net emissions from EOR. Such a policy is expected to increase a firm's total carbon dioxide sequestration. The second chapter statistically estimates the theoretical oil production model and its different versions. Empirical results are not robust over different estimation techniques and not in line with the theoretical production model. The last part of the second chapter utilizes a simplified version of theoretical model and concludes that EOR via CO2 injection improves oil recovery. The final chapter analyzes how a contemporary oil recovery technology (water flooding of oil reservoirs) and various reservoir-specific geological factors influence oil recovery in Wyoming. The results show that there is a positive concave relationship between cumulative water injection and cumulative oil recovery and also show that certain geological factors affect the oil recovery. Moreover, the curvature of the concave functional relationship between cumulative water injection and oil recovery is reservoir-specific due to heterogeneities among different reservoirs.

Kara, Erdal

90

PUBLISHED BY THE AMERICAN ARACHNOLOGICAL SOCIETY A new approach to examining scorpion peg sensilla: the mineral oil flood technique  

E-print Network

: the mineral oil flood technique Elizabeth D. Knowlton and Douglas D. Gaffin: Department of Zoology, University peg sensilla: the mineral oil flood technique Elizabeth D. Knowlton and Douglas D. Gaffin: Department opening. We developed an improved method of chemical stimulant delivery called the mineral oil flood

Gaffin, Doug

91

Micro-agglomerate flotation for deep cleaning of coal. Quarterly progress report, January 1--March 31, 1994  

SciTech Connect

We are investigating the use of a hybrid process -- Micro-agglomerate flotation which is a combination of oil-agglomeration and froth flotation. The basic concept is to use small quantities of oil to promote the formation of dense micro-agglomerates with minimal entrapment of water and mineral particles, and to use froth flotation to extract these micro-agglomerates from the water/dispersed-mineral phase. Since the floating units are agglomerates (about 30--50 {mu}m in size) rather than individual coal particles (1--10 {mu}m) the problems of froth overload and water/mineral carryover should be significantly alleviated. Micro-agglomerate flotation has considerable potential for the practical deep cleaning of coal on a commercial scale. In principle, it should be possible to achieve both high selectivity and high yield at reasonable cost. The process requires only conventional, off-the-shelf equipment and reagent usage (oil, surfactants, etc.) should be small. There are, however, complications. The process involves at least five phases- two or more solids (coal and mineral), two liquids (oil and water) and one gas (air). It is necessary to maintain precise control over the chemistry of the liquid phases in order to promote the interfacial reactions and interactions between phases necessary to ensure selectivity. Kinetics as well as thermodynamic factors may be critical in determining overall system response.

Chander, S.; Hogg, R.

1994-04-01

92

Micro-agglomerate flotation for deep cleaning of coal. Quarterly progress report, September 30--December 31, 1992  

SciTech Connect

We are investigating the use of a hybrid process - Micro-agglomerate flotation - which is a combination of oil-agglomeration and froth flotation. The basic concept is to use small quantities of oil to promote the formation of dense micro-agglomerates with minimal entrapment of water and mineral particles, and to use froth flotation to extract these micro-agglomerates from the water/dispersed-mineral phase. Since the floating units are agglomerates (about 30--50 {mu}m in size) rather than individual coal particles (1--10 {mu}m) the problems of froth overload and water/mineral carryover should be significantly alleviated. Micro-agglomerate flotation has considerable potential for the practical deep cleaning of coal on a commercial scale. In principle, it should be possible to achieve both high selectivity and high yield at reasonable cost. The process requires only conventional, off-the-shelf equipment and reagent usage (oil, surfactants, etc.) should be small. There are, however, complications. The process involves at least five phases: two or more solids (coal and mineral), two liquids (oil and water) and one gas (air). It is necessary to maintain precise control over the chemistry of the liquid phases in order to promote the interfacial reactions and interactions between phases necessary to ensure selectivity. Kinetics as well as thermodynamic factors may be critical in determining overall system response.

Chander, S.; Hogg, R.

1993-01-01

93

Electrostatic formation of liquid marbles and agglomerates  

NASA Astrophysics Data System (ADS)

We report observations of a sudden, explosive release of electrostatically charged 100 ?m 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.

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

2013-07-01

94

Development of methods to predict agglomeration and disposition in FBCs  

SciTech Connect

This 3-year, multiclient program is providing the information needed to determine the behavior of inorganic components in FBC units using advanced methods of analysis coupled with bench-scale combustion experiments. The major objectives of the program are as follows: (1) To develop further our advanced ash and deposit characterization techniques to quantify the effects of the liquid-phase components in terms of agglomerate formation and ash deposits, (2) To determine the mechanisms of inorganic transformations that lead to bed agglomeration and ash deposition in FBC systems, and (3) To develop a better means to predict the behavior of inorganic components as a function of coal composition, bed material characteristics, and combustion conditions.

Mann, M.D.; Henderson, A.K.; Swanson, M.K.; Erickson, T.A.

1995-11-01

95

An empirical study of an agglomeration network  

NASA Astrophysics Data System (ADS)

Recently, researchers have reported many models mimicking real network evolution growth, among which some are based on network aggregation growth. However, until now, relatively few experiments have been reported. Accordingly, in this paper, photomicrographs of real materials (the agglomeration in the filtrate of slurry formed by a GaP-nanoparticle conglomerate dispersed in water) are analyzed within the framework of complex network theory. By data mapping from photomicrographs we generate undirected networks and as a definition of degree we adopt the number of pixel's nearest neighbors while adjacent pixels define a connection or an edge. We study the topological structure of these networks including degree distribution, clustering coefficient and average path length. In addition, we discuss the self-similarity and synchronizability of the networks. We find that the synchronizability of high-concentration agglomeration is better than that of low-concentration agglomeration; we also find that agglomeration networks possess good self-similar features.

Zhang, Yichao; Zhang, Zhaochun; Guan, Jihong

2007-10-01

96

Hydrate plug prevention by anti-agglomeration  

Microsoft Academic Search

Dispersing hydrates into a condensate phase by anti-agglomerants is an alternative to kinetic or thermodynamic inhibitors to prevent hydrate plug formation in a gas production pipeline. In this work, both commercially available surfactants and synthesized anti-agglomerants were tested in high-pressure apparatuses at typical pipeline conditions. Candidates from families of commercially available surfactants, chosen based on their hydrophilic–lipophilic balance (HLB), were

Z Huo; E Freer; M Lamar; B Sannigrahi; D. M Knauss; E. D Sloan

2001-01-01

97

Anti-agglomeration Subsidies with Heterogeneous Firms  

Microsoft Academic Search

This paper studies anti-agglomeration subsidies in a core-periphery setting when firms are heterogeneous in terms of efficiency, focusing on the positive and normative effects of various subsidy forms (specific versus proportional), various tax-financing schemes (local versus global) and various capital-labour endowment ratios (symmetric versus asymmetric). Anti-agglomeration subsidies are shown to have ambiguous welfare effects and the determinants of the sign

Toshihiro Okubo

2006-01-01

98

Transformation of Resources to Reserves: Next Generation Heavy-Oil Recovery Techniques  

SciTech Connect

This final report and technical progress report describes work performed from October 1, 2004 through September 30, 2007 for the project 'Transformation of Resources to Reserves: Next Generation Heavy Oil Recovery Techniques', DE-FC26-04NT15526. Critical year 3 activities of this project were not undertaken because of reduced funding to the DOE Oil Program despite timely submission of a continuation package and progress on year 1 and 2 subtasks. A small amount of carried-over funds were used during June-August 2007 to complete some work in the area of foamed-gas mobility control. Completion of Year 3 activities and tasks would have led to a more thorough completion of the project and attainment of project goals. This progress report serves as a summary of activities and accomplishments for years 1 and 2. Experiments, theory development, and numerical modeling were employed to elucidate heavy-oil production mechanisms that provide the technical foundations for producing efficiently the abundant, discovered heavy-oil resources of the U.S. that are not accessible with current technology and recovery techniques. Work fell into two task areas: cold production of heavy oils and thermal recovery. Despite the emerging critical importance of the waterflooding of viscous oil in cold environments, work in this area was never sanctioned under this project. It is envisioned that heavy oil production is impacted by development of an understanding of the reservoir and reservoir fluid conditions leading to so-called foamy oil behavior, i.e, heavy-oil solution gas drive. This understanding should allow primary, cold production of heavy and viscous oils to be optimized. Accordingly, we evaluated the oil-phase chemistry of crude oil samples from Venezuela that give effective production by the heavy-oil solution gas drive mechanism. Laboratory-scale experiments show that recovery correlates with asphaltene contents as well as the so-called acid number (AN) and base number (BN) of the crude oil. A significant number of laboratory-scale tests were made to evaluate the solution gas drive potential of West Sak (AK) viscous oil. The West Sak sample has a low acid number, low asphaltene content, and does not appear foamy under laboratory conditions. Tests show primary recovery of about 22% of the original oil in place under a variety of conditions. The acid number of other Alaskan North Slope samples tests is greater, indicating a greater potential for recovery by heavy-oil solution gas drive. Effective cold production leads to reservoir pressure depletion that eases the implementation of thermal recovery processes. When viewed from a reservoir perspective, thermal recovery is the enhanced recovery method of choice for viscous and heavy oils because of the significant viscosity reduction that accompanies the heating of oil. One significant issue accompanying thermal recovery in cold environments is wellbore heat losses. Initial work on thermal recovery found that a technology base for delivering steam, other hot fluids, and electrical heat through cold subsurface environments, such as permafrost, was in place. No commercially available technologies are available, however. Nevertheless, the enabling technology of superinsulated wells appears to be realized. Thermal subtasks focused on a suite of enhanced recovery options tailored to various reservoir conditions. Generally, electrothermal, conventional steam-based, and thermal gravity drainage enhanced oil recovery techniques appear to be applicable to 'prime' Ugnu reservoir conditions to the extent that reservoir architecture and fluid conditions are modeled faithfully here. The extent of reservoir layering, vertical communication, and subsurface steam distribution are important factors affecting recovery. Distribution of steam throughout reservoir volume is a significant issue facing thermal recovery. Various activities addressed aspects of steam emplacement. Notably, hydraulic fracturing of horizontal steam injection wells and implementation of steam trap control that limits steam entry into hor

Stanford University; Department of Energy Resources Engineering Green Earth Sciences

2007-09-30

99

Agglomeration of Pt thin films on dielectric substrates  

NASA Astrophysics Data System (ADS)

The agglomeration of metal thin films on dielectric materials is a topic of high technological importance. In this contribution, a coupled morphology-agglomeration approach has been chosen to reveal the basic mechanism of rupture, mass transport, and the substrate dependence of agglomeration. The morphological evolution of Pt thin films has been investigated by means of scanning electron microscopy, atomic force microscopy, and focused ion-beam (FIB) etching techniques. Pt thin films were deposited on amorphous Si3N4 and polycrystalline yttria stabilized ZrO2 substrates and subjected to heat treatments up to 1193 K for 2 h. Three main observations have been made: (i) the early stage of rupture can be described via basic thermodynamics as an order-disorder transition. The dominating mechanism of initial film rupture is a defect associated barrierless nucleation of holes in the spinodal regime of the Pt thin film as shown by means of Minkowski measures. (ii) Up to 1073 K the hole growth is found to be a surface-diffusion limited process, and in first approximation it is in agreement with Brandon and Bradshaw’s theory for the morphological evolution of thin metal films at elevated temperatures. Values for mass transport have been derived. (iii) It is shown that two in general independent physical processes control the morphological evolution and kinetics of thin-film agglomeration: one attributes to the film-ambient interface and the other to the film-substrate interface. Void formation at the film-substrate interface is enhanced by a factor of 9 in the case of the amorphous-crystalline interface due to a lower adhesion energy of the film. The corresponding adhesion energies have been determined experimentally using FIB techniques and the Wulff-Kaishew theorem for equilibrium crystal shapes.

Galinski, H.; Ryll, T.; Elser, P.; Rupp, J. L. M.; Bieberle-Hütter, A.; Gauckler, L. J.

2010-12-01

100

High concentration agglomerate dynamics at high temperatures.  

PubMed

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. PMID:17107027

Heine, M C; Pratsinis, S E

2006-11-21

101

Development of Improved Oil Field Waste Injection Disposal Techniques  

SciTech Connect

The goals of this project have was to: (1) assemble and analyze a comprehensive database of past waste injection operations; (2) develop improved diagnostic techniques for monitoring fracture growth and formation changes; (3) develop operating guidelines to optimize daily operations and ultimate storage capacity of the target formation; and (4) to apply these improved models and guidelines in the field.

Terralog Technologies

2002-11-25

102

Mechanics and charging of nanoparticle agglomerates  

NASA Astrophysics Data System (ADS)

This thesis consists of two parts. The first part concerns studies on mechanics of real agglomerate particles and the second part involves studies on unipolar diffusion charging of agglomerates. Understanding mechanics of real agglomerate particles consisting of multiple primary particles is important for aerosol sizing instrumentation using electrical mobility and nanoparticle manufacturing process where coagulation and sedimentation occur. A key quantity determining transport properties of agglomerates is the friction coefficient. However, quantitative studies for the friction coefficient of agglomerates are very limited. Transmission Electron Microscopy (TEM) image analysis results of silver agglomerates provides a basis for the comparison of experimental data with estimates based on free molecular models. A new quantitative method to determine the dynamic shape factor and the two exponents, eta and Dfm, which characterize the power law dependence of friction coefficient on the number of primary spheres and the mass on the mobility diameter, was developed using Differential Mobility Analyzer (DMA)-Aerosol Particle Mass (APM) analyzer. Model predictions indicate that eta is independent of agglomerate size while Dfm is sensitive to agglomerate size. Experimentally, it appears the opposite is true. Tandem DMA (TDMA) results also show that the mass-mobility diameter scaling exponent is not dependent on mobility size range. Estimates of non-ideal effects on the agglomerate dynamics were computed as perturbations to the Chan-Dahneke agglomerate model. After the corrections, an agreement between experimental data and model predictions becomes significantly improved. Unipolar diffusion charging becomes more attractive because it has higher charging efficiency than bipolar charging as well as important applications in aerosol sizing instrumentation using electrical mobility, powder coating, and the removal of toxic particles from air stream using Electrostatic Precipitator. It has been reported that the particle morphology affects both bipolar and unipolar charging processes. Nevertheless, knowledge about the charging of non-spherical particles such as asbestos fibers and fractal agglomerates is still lacking. From this study it was found that the effect of dielectric constant of materials on unipolar diffusion charging of nanoparticles is very small and the experimental results are in a good agreement with Fuchs (1963)' theory. The effect of agglomerate morphology on unipolar charging characteristic was examined both experimentally and analytically in terms of the mean charge per particle. Both geometric surface area and electrical capacitance are known as two important parameters to determine the mean charge of non-spherical particles. A new model to predict the electrical capacitance of loose agglomerate particles as a function of mobility diameter was developed incorporating electrical mobility and electrostatics theories. This study shows that the electrical capacitance contributes to increase the mean charge per particle of agglomerates more than the geometric surface area, especially in the transition regime. The estimates of geometric surface area and electrical capacitance were used to predict the mean charge from Chang (1981)'s model and the predicted results are reasonably in good agreement with experimental data.

Shin, Weon Gyu

103

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

PubMed

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. PMID:22127372

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

2012-01-23

104

Segmentation Techniques for Identification and Tracking of Oil Spills in Ocean Surface M. Gonzalo-Tasis* a  

E-print Network

Segmentation Techniques for Identification and Tracking of Oil Spills in Ocean Surface M. Gonzalo for self-location, correction of effects arising from skew projections and an evaluation of oil spills in the environment by the oil spill in the ocean. The increase of the marine traffic in zones of straits is a factor

Llanos, Diego R.

105

Time-domain technique for measurement of the dielectric properties of oil shale during processing  

SciTech Connect

A time-domain technique for the measurement of the dielectric properties of oil shale over a broad frequency range is described. The advantages of this technique, which can be used to study chemical changes occurring during the rapid heating of the shale, include simplicity of the procedure, relatively cheap equipment required, and the considerably shorter time to do the measurements as compared with frequency-domain methods. Preliminary results illustrate the feasibility of this method.

Iskander, M.F.; Tyler, A.L.; Elkins, D.F.

1981-06-01

106

Oil spill removal techniques and equipment. (Latest citations from Fluidex). Published Search  

SciTech Connect

The bibliography contains citations concerning equipment and techniques for the control, dispersal, cleanup, and disposal of oil spills. Topics include chemical dispersants, booms, and mechanical skimmers. The citations emphasize spill removal for harbors, estuaries, and shorelines, and examine spill impact on water birds and marine life. (Contains a minimum of 195 citations and includes a subject term index and title list.)

Not Available

1993-12-01

107

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

PubMed

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. PMID:22531845

Wong, Tin Wui; Musa, Nafisah

2012-07-01

108

Oil spill classification from multi-spectral satellite images: exploring different machine learning techniques  

NASA Astrophysics Data System (ADS)

This work describes the potential of oil spill classification from optical satellite images, as investigated by applying different machine learning techniques to a dataset of more than 300 oil spill candidates, which have been detected from multi-spectral satellite sensors during the years 2008 and 2009, over the entire area of the Mediterranean Sea. A set of geometrical and grey level features from Synthetic Aperture Radar (SAR) literature has been extracted from the regions of interest in order to characterize possible oil spills and feed the classification system. Results obtained by applying different machine learning classifiers to the dataset, and the achieved performance are discussed. In particular, as a first approach to oil spill classification, simple statistical classifiers and neural networks were used. Then, a more interpretable fuzzy rule-based classifier was employed, and performance evaluation was refined by exploiting Receiver Operating Characteristic (ROC) analysis. Finally, since oil spill dataset collection happens incrementally, a suitable technique for online classification was proposed, encompassing at the same time cost-oriented classification, in order to allow for a dynamic change of the misclassification costs. This latter goal has been achieved by building an ensemble of cost-oriented, incremental and decremental support vector machines, exploiting the concept of the ROC convex hull.

Corucci, Linda; Nardelli, Fabio; Cococcioni, Marco

2010-10-01

109

Oil-field wastewater purification by magnetic separation technique using a novel magnetic nanoparticle  

NASA Astrophysics Data System (ADS)

In the present work, oil-field wastewater purification through superconducting magnetic separation technique using a novel magnetic nanoparticle was investigated. The magnetic nanoparticle, which has a multi-shell structure with ferroferric oxide as core, dense nonporous silica as inter layer and mesoporous silica as outer layer, was synthesized by co-precipitation method. To functionalize the magnetic nanoparticle, plasma polymerization technique was adopted and poly methyl acrylate (PMA) was formed on the surface of the nanoparticle. The multi-shell structure of the nanoparticle was confirmed by transmission electron microscope (TEM) and the characteristic is measurable by FTIR. It is found that most of the pollutants (85% by turbidity or 84% by COD value) in the oil-field wastewater are removed through the superconducting magnetic separation technique using this novel magnetic nanoparticle.

Liu, Zhuonan; Yang, Huihui; Zhang, Hao; Huang, Chuanjun; Li, Laifeng

2012-12-01

110

Search for Free Fractional Electric Charge Elementary Particles Using an Automated Millikan Oil Drop Technique  

NASA Astrophysics Data System (ADS)

We have carried out a direct search in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied-about 17.4 mg of silicone oil. The search used an improved and highly automated Millikan oil drop technique. No evidence for fractional charge particles was found. The concentration of particles with fractional charge more than 0.16e ( e being the magnitude of the electron charge) from the nearest integer charge is less than 4.71×10-22 particles per nucleon with 95% confidence.

Halyo, V.; Kim, P.; Lee, E. R.; Lee, I. T.; Loomba, D.; Perl, M. L.

2000-03-01

111

DETERMINATION OF STOKES SHAPE FACTOR FOR SINGLE PARTICLES AND AGGLOMERATES  

SciTech Connect

The large octahedral crystals of spinel can precipitate from glass during the high-level waste vitrification process and potentially block the glass discharge riser of electrically heated ceramic melters. To help predict the settling behavior of spinel in the riser, the settling of single particles and agglomerates was studied in stagnant and transparent viscosity oils at room temperature with developed optical particle-dynamics-analyzer. Determined dimensions and terminal settling velocities of particles were used for calculation of their Stokes shape factors. Calculated shape factor for the glass beads was almost identical with the theoretical shape factor of 2/9 for a perfect sphere. The shape factor for single spinel crystal was about 7.6 % higher compare to the theoretically predicted value for octahedron. Stokes shape factor of irregularly shaped multi-particle agglomerates was lower than that of the glass beads and individual spinel crystals because of the higher surface drag caused by the larger surface area to volume ratio.

Matyas, Josef; Schaible, Micah J.; Vienna, John D.

2011-09-01

112

A New Screening Methodology for Improved Oil Recovery Processes Using Soft-Computing Techniques  

NASA Astrophysics Data System (ADS)

The first stage of production of any oil reservoir involves oil displacement by natural drive mechanisms such as solution gas drive, gas cap drive and gravity drainage. Typically, improved oil recovery (IOR) methods are applied to oil reservoirs that have been depleted naturally. In more recent years, IOR techniques are applied to reservoirs even before their natural energy drive is exhausted by primary depletion. Descriptive screening criteria for IOR methods are used to select the appropriate recovery technique according to the fluid and rock properties. This methodology helps in assessing the most suitable recovery process for field deployment of a candidate reservoir. However, the already published screening guidelines neither provide information about the expected reservoir performance nor suggest a set of project design parameters, which can be used towards the optimization of the process. In this study, artificial neural networks (ANN) are used to build a high-performance neuro-simulation tool for screening different improved oil recovery techniques: miscible injection (CO2 and N2), waterflooding and steam injection processes. The simulation tool consists of proxy models that implement a multilayer cascade feedforward back propagation network algorithm. The tool is intended to narrow the ranges of possible scenarios to be modeled using conventional simulation, reducing the extensive time and energy spent in dynamic reservoir modeling. A commercial reservoir simulator is used to generate the data to train and validate the artificial neural networks. The proxy models are built considering four different well patterns with different well operating conditions as the field design parameters. Different expert systems are developed for each well pattern. The screening networks predict oil production rate and cumulative oil production profiles for a given set of rock and fluid properties, and design parameters. The results of this study show that the networks are able to recognize the strong correlation between the displacement mechanism and the reservoir characteristics as they effectively forecast hydrocarbon production for different types of reservoir undergoing diverse recovery processes. The artificial neuron networks are able to capture the similarities between different displacement mechanisms as same network architecture is successfully applied in both CO2 and N2 injection. The neuro-simulation application tool is built within a graphical user interface to facilitate the display of the results. The developed soft-computing tool offers an innovative approach to design a variety of efficient and feasible IOR processes by using artificial intelligence. The tool provides appropriate guidelines to the reservoir engineer, it facilitates the appraisal of diverse field development strategies for oil reservoirs, and it helps to reduce the number of scenarios evaluated with conventional reservoir simulation.

Parada, Claudia; Ertekin, Turgay

2010-05-01

113

Gasdynamic agglomeration of aerosols. I. Acoustic waves  

Microsoft Academic Search

In this paper acoustic agglomeration of aerosols is studied in its simplest form, using a time-averaged form of the coalescence equations. An acoustic coagulation kernel is introduced that neglects all nonlinear effects, as well as particle interactions. Based on this model, it is shown that an acoustic frequency exists that optimizes the coalescence process. This optimum frequency does not have

S. Temkin

1994-01-01

114

SPATIAL IMPACTS OF AGGLOMERATION EXTERNALITIES &ast  

Microsoft Academic Search

ABSTRACT.?This article examines the extent to which agglomeration economies in one location affect employment growth and establishment births, using data from the Dutch province of South-Holland. The data are of particular interest because they represent a census, rather than a sample, of all establishments and the location of establishments can be pinpointed to within 416 (postal) zip code areas averaging

Daan P. van Soest; Shelby Gerking; Frank G. van Oort

2006-01-01

115

Soft- and hard-agglomerate aerosols made at high temperatures.  

PubMed

Criteria for aerosol synthesis of soft-agglomerate, hard-agglomerate, or even nonagglomerate particles are developed on the basis of particle sintering and coalescence. Agglomerate (or aggregate) particles are held together by weak, physical van der Waals forces (soft agglomerates) or by stronger chemical or sintering bonds (hard agglomerates). Accounting for simultaneous gas phase chemical reaction, coagulation, and sintering during the formation and growth of silica (SiO2) nanoparticles by silicon tetrachloride (SiCl4) oxidation and neglecting the spread of particle size distribution, the onset of hard-agglomerate formation is identified at the end of full coalescence, while the onset of soft-agglomerate formation is identified at the end of sintering. Process conditions such as the precursor initial volume fraction, maximum temperature, residence time, and cooling rate are explored, identifying regions for the synthesis of particles with a controlled degree of agglomeration (ratio of collision to primary particle diameters). PMID:16459612

Tsantilis, Stavros; Pratsinis, Sotiris E

2004-07-01

116

Comparing Parameter Estimation Techniques for an Electrical Power Transformer Oil Temperature Prediction Model  

NASA Technical Reports Server (NTRS)

This paper examines various sources of error in MIT's improved top oil temperature rise over ambient temperature model and estimation process. The sources of error are the current parameter estimation technique, quantization noise, and post-processing of the transformer data. Results from this paper will show that an output error parameter estimation technique should be selected to replace the current least squares estimation technique. The output error technique obtained accurate predictions of transformer behavior, revealed the best error covariance, obtained consistent parameter estimates, and provided for valid and sensible parameters. This paper will also show that the output error technique should be used to minimize errors attributed to post-processing (decimation) of the transformer data. Models used in this paper are validated using data from a large transformer in service.

Morris, A. Terry

1999-01-01

117

Control of agglomerate attributes in a continuous binder-agglomeration process  

Microsoft Academic Search

The scope of agglomeration processing includes many different materials over wide scales of production, from specialty materials and pharmaceuticals made in kg\\/day batches to continuous processes for detergents and fertilizers measured in tons\\/h. Agglomeration adds value to the product, for example, producing free-flowing, dust-free particles that are optimized for uses such as tableting, dispersion\\/dissolution and compact delivery (i.e., increase the

Paul R Mort; Scott W Capeci; James W Holder

2001-01-01

118

Technical constraints limiting application of enhanced oil recovery techniques to petroleum production in the United States  

SciTech Connect

In the interval since the publication in September 1980 of the technical constraints that inhibit the application of enhanced oil recovery techniques in the United States, there has been a large number of successful field trials of enhanced oil recovery (EOR) techniques. The Department of Energy has shared the costs of 28 field demonstrations of EOR with industry, and the results have been made available to the public through DOE documents, symposiums and the technical literature. This report reexamines the constraints listed in 1980, evaluates the state-of-the-art and outlines the areas where more research is needed. Comparison of the 1980 constraints with the present state-of-the-art indicates that most of the constraints have remained the same; however, the constraints have become more specific. 26 references, 6 tables.

Not Available

1984-01-01

119

Increased Oil Production and Reserves from Improved Completion Techniques in the Bluebell Field, Uinta Basin, Utah  

SciTech Connect

The objective of this project is to increase oil production and reserves in the Uinta Basin by demonstrating improved completion techniques. Low productivity of Uinta Basin wells is caused by gross production intervals of several thousand feet that contain perforated thief zones, water-bearing zones, and unperforated oil-bearing intervals. Geologic and engineering characterization and computer simulation of the Green River and Wasatch Formations in the Bluebell field will determine reservoir heterogeneities related to fractures and depositional trends. This will be followed by drilling and recompletion of several wells to demonstrate improved completion techniques based on the reservoir characterization. Transfer of the project results will be an ongoing component of the project.

Morgan, Craig D.

1999-11-01

120

Oil spill removal techniques and equipment. (Latest citations from fluidex). Published Search  

SciTech Connect

The bibliography contains citations concerning the development and assessment of techniques and equipment used to control and remove oil spills. Chemical dispersants, booms, and mechanical skimmers are reviewed. Topics include recovery operations, emergency response, frogmat systems, bioremediation, and environmental monitoring. The effects of spills on marine life and fishing industries are examined. (Contains 50-250 citations and includes a subject term index and title list.)

NONE

1995-06-01

121

Effect of temperature on wet agglomeration of crystals  

PubMed Central

Objective(s): This study dealt with the wet agglomeration process in which a small quantity of binder liquid was added into a suspension of crystals, directly in the stirring vessel where the crystallization took place. The purpose of this investigation was evaluation of the effect of temperature on the agglomeration process in order to gain insight into the mechanism of the formation of the agglomerates. Materials and Methods: Carbamazepine was used as a model drug and water/ethanol and isopropyl acetate were used as crystallization system and binder liquid, respectively. The agglomeration of crystals was carried out at various temperatures and the agglomerates were characterized in terms of size, morphology, density and mechanical strength. Results: Evaluation of the agglomerates along the course of agglomeration shows that the properties of the particles change gradually but substantially. Higher temperature of the system during agglomeration process favors the formation of more regular agglomerates with mechanically stronger and denser structure; this can be explained by the promotion effect of temperature on the agglomeration process. Conclusion: With optimized wet agglomeration temperature, spherical, dense, and strong agglomerates can be obtained. PMID:24967063

Maghsoodi, Maryam; Yari, Zahra

2014-01-01

122

Migration and dynamic agglomeration economies: Regional income growth in Norway  

Microsoft Academic Search

The existence of agglomeration economies is well established. We study dynamic agglomeration effects and expect regional income divergence when people move from the periphery to cities. We use distribution analysis, Kernel density functions and first order Markov chains, to investigate whether data from Norwegian regions 1972-2008 with strong urbanization are consistent with agglomeration effects. The analysis shows overall income convergence,

2011-01-01

123

Population balance based modelling of nickel laterite agglomeration behaviour  

Microsoft Academic Search

Agglomeration of fine mineral particles as a precursor to heap leaching is an important means of enhancing leaching rates and metal recoveries, particularly in processing low grade ores. In this paper, the modelling of a batch drum agglomeration process applied to nickel laterite using population balance model is explored. The coalescence kernels which are linked to feed material and agglomerator

L. X. Liu; D. J. Robinson; J. Addai-Mensah

124

Modelling of the agglomeration in suspension process with multidimensional kernels  

Microsoft Academic Search

This paper deals with the modelling and the simulation of an agglomeration in suspension process. It is shown how classical kernel models (constant, sum or product kernel) based only on the agglomerate size are inappropriate to represent such a complex process. A methodology for the elaboration of a phenomenological multidimensional kernel considering both liquid binding composition and size agglomerate is

L Madec; L Falk; E Plasari

2003-01-01

125

The discrete agglomeration model with a time-varying kernel  

Microsoft Academic Search

Agglomeration of particles in a fluid environment occurs in industrial processes and is studied experimentally. The fundamental process has been modeled using the agglomeration (coagulation or Smoluchowski) equation. This paper examines the discrete agglomeration model with a time-varying kernel.

James L. Moseley

2007-01-01

126

Managing the attractiveness of evolved and created retail agglomerations formats  

Microsoft Academic Search

Purpose – The purpose of this paper is to identify those attributes of created and evolved retail agglomeration formats that have a substantial impact on overall attractiveness from the consumers' point of view. From an agglomeration management perspective primary areas of concern are identified and suggestions to increase the competitiveness of diverse agglomeration formats are presented. Design\\/methodology\\/approach – Through synthesizing

Christoph Teller; Jonathan Elms

2010-01-01

127

Gas hydrate anti-agglomerant properties of polypropoxylates and some other demulsifiers  

Microsoft Academic Search

Low dosage hydrate inhibitors (LDHIs) have been developed over the last 15 yr as a new gas hydrate control technology for the oil industry, which can be more cost-effective than traditional practices such as the use of thermodynamic inhibitors e.g. methanol and glycols. Two classes of LDHI called kinetic inhibitors (KHIs) and anti-agglomerants (AAs) are already being successfully used in the

Malcolm A. Kelland; Thor Martin Svartås; Lindy Dybvik Andersen

2009-01-01

128

Influence of polymerization on the synthesis of SrTiO 3: Part II. Particle and agglomerate morphologies  

Microsoft Academic Search

Morphologies of SrTiO3 particles and agglomerates synthesized by the traditional Pechini route and by the polymer precipitation route were characterized by the nitrogen adsorption\\/desorption technique and by transmission electron microscopy (TEM). A cluster structure of nanometric particles forming large agglomerates which are broken during pressing followed by cluster rearrangement was observed. The mean particle size is larger for SrTiO3 obtained

E. R. Leite; J. A. Varela; E. Longo; C. A. Paskocimas

1995-01-01

129

Modeling Agglomeration of Dust Particles in Plasma  

SciTech Connect

The charge on an aggregate immersed in a plasma environment distributes itself over the aggregate's surface; this can be approximated theoretically by assuming a multipole distribution. The dipole-dipole (or higher order) charge interactions between fractal aggregates lead to rotations of the grains as they interact. Other properties of the dust grains also influence the agglomeration process, such as the monomer shape (spherical or ellipsoidal) or the presence of magnetic material. Finally, the plasma and grain properties also determine the morphology of the resultant aggregates. Porous and fluffy aggregates are more strongly coupled to the gas, leading to reduced collisional velocities, and greater collisional cross sections. These factors in turn can determine the growth rate of the aggregates and evolution of the dust cloud. This paper gives an overview of the numerical and experimental methods used to study dust agglomeration at CASPER and highlights some recent results.

Matthews, Lorin S.; Land, Victor; Ma Qianyu; Perry, Jonathan D.; Hyde, Truell W. [Center for Astrophysics, Space Physics, and Engineering Research Baylor University, One Bear Place 97310, Waco, Texas 76798-7310 (United States)

2011-11-29

130

Determination of peroxide value of edible oils by FTIR spectroscopy with the use of the spectral reconstitution technique  

Microsoft Academic Search

Spectral reconstitution (SR), a technique that has been developed to facilitate mid-FTIR transmission analysis of inherently viscous samples, was applied to simplify and automate a previously reported FTIR method for the determination of peroxide value (PV) of edible oils. The basis of the PV determination is the rapid reaction of triphenylphosphine (TPP) with the hydroperoxides present in an oil to

Xiuzhu Yu; F. R. van de Voort; J. Sedman

2007-01-01

131

The application of hyperspectral image techniques on MODIS data for the detection of oil spills in the RSA1  

E-print Network

The application of hyperspectral image techniques on MODIS data for the detection of oil spills for the Protection of Marine Environment, Kuwait; b School of Ocean and Earth Science, University of Southampton as look-alike, when the distinct oil pattern was not visible in the standard MODIS algorithm

Quartly, Graham

132

Anti-agglomeration Subsidies with Heterogeneous Firms  

Microsoft Academic Search

This paper studies anti-agglomeration subsidies in a core-periphery setting when firms are heterogeneous in labour productivity, focusing on the effects of relocation subsidy on firm location in various tax-financing schemes (local versus global). We discuss how subsidy can enhance welfare in periphery. As a result we find that subsidy proportional to profits can induce the relocation of high productivity firms

Toshihiro Okubo

2011-01-01

133

Anti-agglomeration Subsidies with Heterogeneous Firms  

Microsoft Academic Search

This paper studies anti-agglomeration subsidies in a core-periphery setting when firms are heterogeneous in labour productivity, focusing on the effects of a relocation subsidy on firm location in various tax-financing schemes (local versus global). We discuss how a subsidy can enhance welfare and average productivity in the periphery. As a result we find that a subsidy proportional to profits can

Toshihiro Okubo

2011-01-01

134

Comparison of soft computing techniques for a three-phase oil field centrifuge.  

SciTech Connect

In this work we compare fuzzy techniques to neural network techniques for building a soft sensor for a three-phase oil field centrifuge. The soft sensor is used in a feed-forward control system that augments a feedback control system. Two approaches were used to develop the soft sensor. The first approach was to use a fuzzy rule based system based upon the experience of an expert operator. The expert operator's experience was supplemented using a computer model of the system. The second approach was to use a neural network to build the inverse of the computer model. The pros and cons of both techniques are discussed. KEYWORDS: fuzzy logic, neural networks, soft sensor, soft computing

Smith, R. E. (Ronald E.); Parkinson, w; Miller, N. (Neal)

2002-01-01

135

The Fluorescent-Oil Film Method and Other Techniques for Boundary-Layer Flow Visualization  

NASA Technical Reports Server (NTRS)

A flow-visualization technique, known as the fluorescent-oil film method, has been developed which appears to be generally simpler and to require less experience and development of technique than previously published methods. The method is especially adapted to use in the large high-powered wind tunnels which require considerable time to reach the desired test conditions. The method consists of smearing a film of fluorescent oil over a surface and observing where the thickness is affected by the shearing action of the boundary layer. These films are detected and identified, and their relative thicknesses are determined by use of ultraviolet light. Examples are given of the use of this technique. Other methods that show promise in the study of boundary-layer conditions are described. These methods include the use of a temperature-sensitive fluorescent paint and the use of a radiometer that is sensitive to the heat radiation from a surface. Some attention is also given to methods that can be used with a spray apparatus in front of the test model.

Loving, Donald L.; Katzoff, S.

1959-01-01

136

Increased Oil Production and Reserves from Improved Completion Techniques in the Bluebell Field, Uinta Basin, Utah  

SciTech Connect

The objective of the project is to increase oil production and reserves by the use of improved reservoir characterization and completion techniques in the Uinta Basin, Utah. To accomplish this objective, a two-year geologic and engineering characterization of the Bluebell field was conducted. The study evaluated surface and subsurface data, currently used completion techniques, and common production problems. It was determined that advanced case- and open-hole logs could be effective in determining productive beds and that stage-interval (about 500 ft [150 m] per stage) and bed-scale isolation completion techniques could result in improved well performance. In the first demonstration well (Michelle Ute well discussed in the previous technical report), dipole shear anisotropy (anisotropy) and dual-burst thermal decay time (TDT) logs were run before and isotope tracer log was run after the treatment. The logs were very helpful in characterizing the remaining hydrocarbon potential in the well. But, mechanical failure resulted in a poor recompletion and did not result in a significant improvement in the oil production from the well.

Deo, M.D.; Morgan, C.D.

1999-04-28

137

Enhanced dissolution rate of felodipine using spherical agglomeration with Inutec SP1 by quasi emulsion solvent diffusion method.  

PubMed

Felodipine is a second generation calcium channel blocker widely used as antihypertensive and antianginal drug which belongs to BCS class II category. Hence, its low water solubility limits the pharmacological effect. The aim of this study was to improve the dissolution rate of felodipine using spherical agglomeration technique with acetone, water and dichloromethane as good solvent, poor solvent and bridging liquid, respectively. The quasi emulsion solvent diffusion technique was used as a method for spherical agglomeration. Inutec SP1 was used as an emulsion stabilizer and as hydrophilic polymer in agglomeration process. The FTIR and DSC results showed no change in the drug after crystallization process. PXRD studies showed sharp peaks in the diffractograms of spherical agglomerates with minor reduction in height of the peaks. The particle size of spherical agglomerates (FI-2) was about 134.33 ± 13.57 µm, n=3 and the dissolution efficiency of felodipine up to 120 min increased to about 4-fold in phosphate buffer containing 1.8% Tween 80 (pH 6.8). Spherical agglomerates showed enhanced solubility compared to untreated powder possibly due to the partial conversion to amorphous form. PMID:21589802

Tapas, A R; Kawtikwar, P S; Sakarkar, D M

2009-07-01

138

Techniques to Improve Cyclic Steam Stimulation of Deep and Extra Heavy Oil Reservoirs in Xiaowa Oil Field  

Microsoft Academic Search

Xiaowa oil field is a fault nose in structure with sandstone res- ervoirs, in which 9.7km 2 oil-bearing area and 3627 × 10 4 t original oil in place is proved. The pay zones that have been developed are Dongying Group and S3 of lower Tertiary. Dongying Group belongs to delta-front regime with good physical properties. S3 belongs to submerged

Cheng Jincai; Yu Hongkun; Yang Xianke; Liu Guiman

1998-01-01

139

Uncertainty Analysis for Oil-Film Interferometry Skin-Friction Measurement Techniques  

NASA Technical Reports Server (NTRS)

Over the past 20 years, the use of oil-film interferometry to measure the skin friction coefficient (C(sub f) = tau/q where tau is the surface shear stress and q is the dynamic pressure) has increased. Different forms of this oil-film technique with various levels of accuracy and ease of use have been successfully applied in a wide range of flows. The method's popularity is growing due to its relative ease of implementation and minimal intrusiveness as well as an increased demand for C(sub f) measurements. Nonetheless, the accuracy of these methods has not been rigorously addressed to date. Most researchers have simply shown that the skin-friction measurements made using these techniques compare favorably with other measurements and theory, most of which are only accurate to within 5-20%. The use of skin-friction data in the design of commercial aircraft, whose drag at cruise is 50% skin-friction drag, and in the validation of computational fluid dynamics programs warrants better uncertainty estimates. Additional information is contained in the original extended abstract.

Naughton, Jonathan W.; Brown, James L.; Merriam, Marshal (Technical Monitor)

1996-01-01

140

Reaction products of densified silica fume agglomerates in concrete  

Microsoft Academic Search

Most silica fume currently used in concrete is in the dry densified form and consists of agglomerates of sizes between 10 ?m and several millimeters. Many of these agglomerates may break down only partially in normal concrete mixing. Examination of various mature silica-fume-bearing concretes using backscatter mode scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis shows that such agglomerates

Sidney Diamond; Sadananda Sahu; Niels Thaulow

2004-01-01

141

Deciphering the effects of agglomeration economies on firms’ productive efficiency  

Microsoft Academic Search

The present work assess the effects of MAR and Jacob’s type agglomeration economies on a sample of firms in the machineries and textiles industries in Greece for the periods 1989-91 and 1999-01. The analysis employs a stochastic production frontier function and allows agglomeration economies to enter as inputs and\\/or as factors reducing inefficiency. Results re-confirm that the effects of agglomeration

Dimitris Skuras; Kostas Tsekouras; Efthalia Dimara

2011-01-01

142

Effect of agglomeration on flowability of baby food powders.  

PubMed

The aim of this study was to investigate the influence of the wet agglomeration in a fluidized bed on flowability of agglomerated products, such as baby food powders. The agglomeration process was performed in the fluidized bed. The wetting liquid used to the process was: water, 2% lecithin solution, and 50% sugar solution. Food powders flowability was expressed as: Hausner Ratio, pouring time, angles of sliding and of repose and flow function. The composition of materials, used to prepare mixtures, has a significant influence on tested properties. The higher milk powder of the mixtures caused decreasing of their flowability. Wet agglomeration of baby food powders caused an increase in the mean diameter of particles, which made it possible to receive agglomerates with good flowability and decreased bulk density. The increase of milk powder content from 0 to 73% in the mixture before the agglomeration contributed to improve its flowability. Wet agglomeration with 2% lecithin solution and 50% sugar solution reduced particle size and bulk density, improved flowability of received agglomerates in relation to agglomerates received with water as a wetting liquid. PMID:20629874

Szulc, Karolina; Lenart, Andrzej

2010-06-01

143

Modeling of crushed ore agglomeration for heap leach operations  

NASA Astrophysics Data System (ADS)

The focus of this dissertation is modeling of the evolution of size distribution in batch agglomeration drum. There has been no successful work on modeling of crushed ore agglomeration although the framework for population balance modeling of pelletization and granulation is readily available. In this study three different batch agglomeration drums were used to study the agglomeration kinetics of copper, gold and nickel ores. The agglomerate size distribution is inherently subject to random fluctuation due the very nature of the process. Yet, with careful experimentation and size analysis the evolution of size distribution can be followed. The population balance model employing the random coalesce model with a constant rate kernel was shown to work well in a micro and lab scale agglomerator experiments. In small drums agglomerates begin to break in a short time, whereas the growth is uniform in the lab scale drum. The experimental agglomerate size distributions exhibit self-preserving size spectra which confirms the applicability of coalescence rate based model. The same spectra became a useful fact for predicting the size distribution with an empirical model. Since moisture is a principal variable, the absolute deviation from optimum moisture was used as the primary variable in the empirical model. Having established a model for the size distribution, the next step was to delve into the internal constituents of each agglomerate size class. To this end, an experimental scheme known as dip test was devised. The outcome of the test was the size distribution of progeny particles which make up a given size class of agglomerate. The progeny size distribution was analyzed with a model that partitions the particles into a host and guest category. The ensuing partition coefficient is a valuable in determining how a particle in a size class participates in larger agglomerates. This dissertation lays out the fundamentals for applying the population balance concept to batch agglomeration, specifically crushed ore agglomeration. The experimental difficulties and how to overcome them are described. An empirical model that is readily useful for plant heap leach operations is shown in detail. The analysis of constituent particles within agglomerate size class is done with a partition model. The guest and host nature of particles, thus delineated, helps one to anticipate the nature of agglomerates that would be formed with a given ore size distribution. Thus, all aspects of batch agglomeration are addressed in this work.

Dhawan, Nikhil

144

Fractal analysis of flocs formed in edible oil-water emulsions by image analysis techniques  

Microsoft Academic Search

Edible oil is an important contaminant in water and wastewater. Oil droplets smaller than 40 ?m may remain in effluent as an emulsion and combine with other contaminants in water. Coagulation\\/flocculation processes are used to remove oil droplets from water and wastewater. By adding a polymer at proper dose, small oil droplets can be flocculated and separated from water. The

Jiranun Hempoonsert

2002-01-01

145

Increased Oil Production and Reserves From Improved Completion Techniques in the Bluebell Field, Uinta Basin, Utah  

SciTech Connect

The Bluebell field is productive from the Tertiary lower Green River and Colton (Wasatch) Formations of the Uinta Basin, Utah. The productive interval consists of thousands of feet of interbedded fractured clastic and carbonate beds deposited in the ancestral Lake Uinta. Wells in the Bluebell field are typically completed by perforating 40 or more beds over 1000 to 3000 vertical ft (300-900 m), then stimulating the entire interval with hydrochloric acid. This technique is often referred to as the shot gun completion. Completion techniques used in the Bluebell field were discussed in detail in the Second Annual Report (Curtice, 1996). The shot-gun technique is believed to leave many potentially productive beds damaged and/or untreated, while allowing water-bearing and low-pressure (thief) zones to communicate with the wellbore. A two-year characterization study involved detailed examination of outcrop, core, well logs, surface and subsurface fractures, produced oil-field waters, engineering parameters of the two demonstration wells, and analysis of past completion techniques and effectiveness. The study was intended to improve the geologic characterization of the producing formations and thereby develop completion techniques specific to the producing beds or facies instead of a shot gun approach to stimulating all the beds. The characterization did not identify predictable-facies or predictable-fracture trends within the vertical stratigraphic column as originally hoped. Advanced logging techniques can identify productive beds in individual wells. A field-demonstration program was developed to use cased-hole advanced logging techniques in two wells and recompletion the wells at two different scales based on the logging. The first well was going to be completed at the interval scale using a multiple stage completion technique (about 500 ft [150 m] per stage). The second well will be recompleted at the bed-scale using bridge plug and packer to isolate three or more beds for stimulation. These recompletion will show which logs are most effective in identifying productive beds and what scale of completion is most cost effective. The third demonstration will be the logging and completion of a new well using the logs and completion scale or technique, most effective in the previous demonstrations.

Morgan, C.D.; Deo, M.D.

1998-04-01

146

Oil  

NSDL National Science Digital Library

The first site, offered by the Institute of Petroleum, is called Fossils into Fuel (1). It describes how oil and gas are formed and processed, as well as offering short quizzes on each section. The second site (2) is maintained by the Department of Energy. Visitors can learn about the history of oil use, how itâÂÂs found and extracted, and more. The next site, called Picture an Oil Well (3), is a one-page illustration and description of the workings of an oil well, offered by the California Department of Conservation. The fourth site, hosted by the Minerals Management Service, is called Stacey Visits an Offshore Oil Rig (4). It tells the story of a girl taking a field trip on an offshore oil rig and what she finds when sheâÂÂs there. The Especially for Kids Web site (5) is presented by NOAA and explores facts about the effects of oil spills. Kids can do experiments, get help writing a report, find further information on the provided additional links, and more. From the Environmental Protection Agency, the sixth site is called Oil Spill Program (6), and it also delves into the topic of oil spills. It provides information about the EPA's program for preventing, preparing for, and responding to oil spills that occur in and around inland waters of the United States. The next site, offered by How Stuff Works.com, is called How Oil Refining Works (7). Descriptions of crude oil, fractional distillation, chemical processing, and more is presented in a succinct but informative way. The last site is from The Center for Subsurface Modeling (CSM) of the Texas Institute for Computational and Applied Mathematics and is called CSMâÂÂs Picture Gallery (8). After clicking the Gallery link, visitors will find animations and images that represent CSMâÂÂs work such as oil spill simulations, discontinuous galerkin, the tyranny of scale, contaminant remediation, etc.

Brieske, Joel A.

2002-01-01

147

Oil whip instability control using ?-synthesis technique on a magnetic actuator  

NASA Astrophysics Data System (ADS)

Rotating machines have a wide application range and since those machines have high trust levels, several rotor vibrations control methods are investigated in order to avoid sudden cracks, improve rotor performance or even to reach higher operation speeds by controlling some instabilities, critical speeds resonances or oil whip effect. Rotor instabilities are associated to the operation speed and can have structural or dynamic sources from the shaft, bearings and foundation or even from an actuator external force. This work focuses on a strategy that uses the ?-synthesis control technique to attenuate the oil whip instability effect of flexible hydrodynamically supported rotors and allows the rotor to operate in higher speeds. For the identified rotor model and the synthesized controller applied on a magnetic actuator, the control system stability and performance specifications are analyzed with regard to the model uncertainties and ?-synthesis controlled vibration levels are compared to PID controller in vertical and horizontal directions. The performance specifications within the ?-synthesis are optimized to suppress unbalance vibration and, in order to contribute to industrial acceptance, the controller design is presented as a strategy which focuses on a design at reduced effort.

Riemann, Bernd; Araujo Perini, Efrain; Lucchesi Cavalca, Katia; Fiori de Castro, Helio; Rinderknecht, Stephan

2013-02-01

148

APPLIED PHYTO-REMEDIATION TECHNIQUES USING HALOPHYTES FOR OIL AND BRINE SPILL SCARS  

SciTech Connect

Produced salt water from historical oil and gas production was often managed with inadequate care and unfortunate consequences. In Kansas, the production practices in the 1930's and 1940's--before statewide anti-pollution laws--were such that fluids were often produced to surface impoundments where the oil would segregate from the salt water. The oil was pumped off the pits and the salt water was able to infiltrate into the subsurface soil zones and underlying bedrock. Over the years, oil producing practices were changed so that segregation of fluids was accomplished in steel tanks and salt water was isolated from the natural environment. But before that could happen, significant areas of the state were scarred by salt water. These areas are now in need of economical remediation. Remediation of salt scarred land can be facilitated with soil amendments, land management, and selection of appropriate salt tolerant plants. Current research on the salt scars around the old Leon Waterflood, in Butler County, Kansas show the relative efficiency of remediation options. Based upon these research findings, it is possible to recommend cost efficient remediation techniques for slight, medium, and heavy salt water damaged soil. Slight salt damage includes soils with Electrical Conductivity (EC) values of 4.0 mS/cm or less. Operators can treat these soils with sufficient amounts of gypsum, install irrigation systems, and till the soil. Appropriate plants can be introduced via transplants or seeded. Medium salt damage includes soils with EC values between 4.0 and 16 mS/cm. Operators will add amendments of gypsum, till the soil, and arrange for irrigation. Some particularly salt tolerant plants can be added but most planting ought to be reserved until the second season of remediation. Severe salt damage includes soil with EC values in excess of 16 mS/cm. Operators will add at least part of the gypsum required, till the soil, and arrange for irrigation. The following seasons more gypsum will be added and as the soil EC is reduced, plants can be introduced. If rapid remediation is required, a sufficient volume of topsoil, or sand, or manure can be added to dilute the local salinity, the bulk amendments tilled into the surface with added gypsum, and appropriate plants added. In this case, irrigation will be particularly important. The expense of the more rapid remediation will be much higher.

M.L. Korphage; Bruce G. Langhus; Scott Campbell

2003-03-01

149

A die pressing test for the estimation of agglomerate strength  

Microsoft Academic Search

A die pressing test was developed for quick and inexpensive estimation of the agglomerate strength of ceramic powders. The critical nominal pressure (p[sub c]) at which contact areas between agglomerates start to increase rapidly was found from the relationship between change in sample height and applied pressure in uniaxial single-ended die pressing. A quantitative microscopic method was used for measuring

Jin-Hua Song; Julian R. G. Evans

1994-01-01

150

Marshallian Agglomeration Economies and Entrepreneurship: The Spanish Case  

Microsoft Academic Search

This paper analyzes to what extent marshallian agglomeration economies affect the creation of new entrepreneurial ventures at the metropolitan level. The measuring of agglomeration economies is based on the construction of indexes using the methodology of Glaeser and Kerr (2009). The indexes attempt to capture the effects of resource sharing, labor matching and knowledge spillovers according to the taxonomy proposed

Roberto Dopeso Fernandez

2011-01-01

151

Spatial Competition and Agglomeration: An Application to Motion Pictures  

Microsoft Academic Search

This paper presents an empirical assessment of movie theatre attendance in two major metropolitan markets and provides strong support for the importance of spatial characteristics in determining attendance. We consider the hypothesis that attendance at a particular movie theatre reflects a tension between two effects: a competition effect and an agglomeration effect. We find evidence that the agglomeration effect dominates.

Darlene C. Chisholm; George Norman

152

Soot agglomeration in isolated, free droplet combustion  

NASA Technical Reports Server (NTRS)

Under the conditions of an isolated, free droplet experiment, hollow, carbonaceous structures, called soot spheres, were observed to form during the atmospheric pressure, low Reynolds number combustion of 1-methylnaphthalene. These structures which are agglomerates composed of smaller spheroidal units result from both thermophoretic effects induced by the envelope flame surrounding each drop and aerodynamic effects caused by changes in the relative gas/drop velocities. A chemically reacting flow model was used to analyze the process of sootshell formation during microgravity droplet combustion. The time-dependent temperature and gas property field surrounding the droplet was determined, and the soot cloud location for microgravity combustion of n-heptane droplets was predicted. Experiments showed that the sooting propensity of n-alkane fuel droplets can be varied through diluent substitution, oxygen-index variations, and ambient pressure reductions.

Choi, M. Y.; Dryer, F. L.; Green, G. J.; Sangiovanni, J. J.

1993-01-01

153

Influence of primary particle density in the morphology of agglomerates  

E-print Network

Agglomeration processes occur in many different realms of science such as colloid and aerosol formation or formation of bacterial colonies. We study the influence of primary particle density in agglomerate structure using diffusion-controlled Monte Carlo simulations with realistic space scales through different regimes (DLA and DLCA). The equivalence of Monte Carlo time steps to real time scales is given by Hirsch's hydrodynamical theory of Brownian motion. Agglomerate behavior at different time stages of the simulations suggests that three indices (fractal exponent, coordination number and eccentricity index) characterize agglomerate geometry. Using these indices, we have found that the initial density of primary particles greatly influences the final structure of the agglomerate as observed in recent experimental works.

M. D. Camejo; D. R. Espeso; L. L. Bonilla

2014-07-03

154

The Structure of Agglomerates consisting of Polydisperse Particles.  

PubMed

Agglomeration is encountered in many natural or industrial processes, like growth of aerosol particles in the atmosphere and during material synthesis or even flocculation of suspensions, granulation, crystallization and with colloidal particle processing. These particles collide by different mechanisms and stick together forming irregular or fractal-like agglomerates. Typically, the structure of these agglomerates is characterized with the fractal dimension, Df , and pre-exponential factor, kn , of simulated agglomerates of monodisperse primary particles (PP) for ballistic or diffusion-limited particle-cluster and cluster-cluster collision mechanisms. Here, the effect of PP polydispersity on Df and kn is investigated with agglomerates consisting of 16 - 1024 PP with closely controlled size distribution (geometric standard deviation, ? g = 1-3). These simulations are in excellent agreement with the classic structure (Df and kn ) of agglomerates consisting of monodisperse PPs made by four different collision mechanisms as well as with agglomerates of bi-, tri-disperse and normally distributed PPs. Broadening the PP size distribution of agglomerates decreases monotonically their Df and for sufficiently broad PP distributions (? g > 2.5) the Df reaches about 1.5 and kn about 1 regardless of collision mechanism. Furthermore with increasing PP polydispersity, the corresponding projected area exponent, D ? , and pre-exponential factor, ka , decrease monotonically from their standard values for agglomerates with monodisperse PPs. So Df as well as D ? and ka can be an indication for PP polydispersity in mass-mobility and light scattering measurements, if the dominant agglomeration mechanism is known, like diffusion-limited and/or ballistic cluster-cluster coagulation in aerosols. PMID:23729953

Eggersdorfer, M L; Pratsinis, S E

2012-03-01

155

Bed material agglomeration during fluidized bed combustion. Final report  

SciTech Connect

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 occur 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).

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

1996-01-01

156

Impact of agglomeration state of nano- and submicron sized gold particles on pulmonary inflammation  

PubMed Central

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

2010-01-01

157

Skin friction measurement in complex flows using thin oil film techniques  

NASA Technical Reports Server (NTRS)

The NASA Grant NAG2-261 was initiated to support a program of research to study complex flows that occur in flight and laboratory experiments by building, testing and optimizing an on-board technique for direct measurement of surface shear stress using thin oil film techniques. The program of research has proceeded under the supervision of the NASA Ames Research Center and with further cooperation from the NASA Ames-Dryden and NASA Langley Research Centers. In accordance with the original statement of work, the following research milestones were accomplished: (1) design and testing of an internally mounted one-directional skin friction meter to demonstrate the feasibility of the concept; (2) design and construction of a compact instrument capable of measuring skin friction in two directions; (3) study of transitional and fully turbulent boundary layers over a flat plate with and without longitudinal pressure gradients utilizing the compact two-directional skin friction meter; (4) study of the interaction between a turbulent boundary layer and a shock wave generated by a compression corner using the two-directional meter; and (5) flight qualification of the compact meter and accompanying electronic and pneumatic systems, preliminary installation into flight test fixture.

1994-01-01

158

Antisolvent induced agglomeration of mineral matter in coal derived liquids. Final report. [83 references  

Microsoft Academic Search

The influence of many of the variables associated with anti-solvent induced agglomeration of mineral matter in coal derived liquids was observed by an indirect x-ray photographic technique. The primary variables were anti-solvent type, dose, combinations of anti-solvent and a gas, temperature, anti-solvent addition rate, and mixing conditions. A correlation is proposed which relates the effectiveness of various anti-solvents, as evidenced

J. D. Jr. Henry; F. H. Verhoff

1979-01-01

159

Novel Binders and Methods for Agglomeration of Ore  

SciTech Connect

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 will 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.

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

2005-09-30

160

Recent improvements in optimizing use of dispersants as a cost-effective oil spill countermeasure technique  

SciTech Connect

Several oil spill incidents during recent years have demonstrated that the physico-chemical properties of spilled oil and the effectiveness of available combat methods are, in addition to the prevailing environmental and weather conditions, key factors that determine the consequences of an oil spill. Pre-spill analyses of the feasibility and effectiveness of different response strategies, such as mechanical recovery and dispersants, for actual oils under various environmental conditions should therefore be an essential part of any oil spill contingency planning to optimize the overall {open_quotes}Net Environmental Benefit{close_quotes} of a combat operation. During the four-year research program ESCOST ({open_quotes}ESSO-SINTEF Coastal Oil Spill Treatment Program{close_quotes}), significant improvements have been made in oil spill combat methods and in tools for use in contingency planning and decision-making during oil spill operations. This paper will present an overview of the main findings obtained with respect to oil weathering and oil spill dispersant treatment.

Daling, P.S.; Indrebo, G.

1996-12-31

161

Investigations into the control of agglomeration and defluidisation during fluidised-bed combustion of low-rank coals  

Microsoft Academic Search

A laboratory scale spouted bed combustor was used to study the effectiveness of various control methodologies in alleviating ash-related problems such as particle agglomeration and bed defluidisation during fluid bed combustion of low-rank coals. The three control techniques investigated are: (i) the use of mineral additives; (ii) alternative bed materials; and (iii) pretreatment of coal. Mineral additives, including dolomite, two

H. B. Vuthaluru; T. M. Linjewile; Dong-ke Zhang; A. R. Manzoori

1999-01-01

162

Increased Oil Production and Reserves from Improved Completion Techniques in the Bluebell Field, Uinta Basin, Utah, Class I  

SciTech Connect

The objective of this project was to increase oil production and reserves by the use of improved reservoir characterization and completion techniques in the Unita Basin Utah. To accomplish this objective, a two-year geologic and engineering characterization of the Bluebell field was conducted. The study evaluated surface and subsurface data, currently used completion techniques, and common production problems. It was determined that advanced case- and open-hole logs could be effective in determining productive beds and that staged-interval (about 500 ft [150 m] per stage) and bed-scale isolation completion techniques could result in improved well performance.

Morgan, Craig D.; Gwynn, Wallace; Deo, Milind D.; Jarrard, Richard; Curtice, Richard; Morris, Thomas H.; Smouse, DeForrest; Tripp, Carol N.

2000-01-20

163

Simulation of particle agglomeration using dissipative particle dynamics  

E-print Network

discharge of aerosol sprays. Aerosol sprays have their application in asthma relievers, coatings, cleaning agents, air fresheners, personal care products and insecticides. There are several factors that cause particle agglomeration and based...

Mokkapati, Srinivas Praveen

2009-05-15

164

What Causes Industry Agglomeration? Evidence from Coagglomeration Patterns  

E-print Network

Why do firms cluster near one another? We test Marshall's theories of industrial agglomeration by examining which industries locate near one another, or coagglomerate. We construct pairwise coagglomeration indices for US ...

Ellison, Glenn

165

In-line method for the beneficiation of coal and the formation of a coal-in-oil combustible fuel therefrom  

Microsoft Academic Search

An in-line method for the beneficiation of coal and the formation of a coal-in-oil combustible fuel wherein the coal is wet pulverized, micro-agglomerated with light oil to dissociate a large amount of inorganic impurities and some water, agglomerated with heavy oil to form relatively larger agglomerates and dissociate mainly water with some inorganic impurities, and then mixed with further heavy

C. Capes; R. D. Coleman; L. Messer; W. L. Thayer

1981-01-01

166

Modelling nano-particle agglomeration using local interactions  

E-print Network

Nano-particle agglomeration plays an important role in processes such as spray drying and particle flame synthesis. These processes have in common that nano-particles collide at low concentrations and get irreversibly linked at the point of contact due to plastic deformation. In this paper, we investigate several models of irreversible connections, which require only local interactions between the colliding nano-particles and thus allow for scalable simulations. The models investigated here connect the particles upon collision by non-bonded strongly attractive interactions, bonded interactions or by binding agents placed at the point of contact. Models using spherically symmetric interactions form compact agglomerates and are therefore unsuitable to study agglomeration. In contrast, models that are either based on both central and angular potentials (type one) or on binding agents (type two) efficiently prevent restructuring of the agglomerates, and are therefore useful for modeling contacts formed by plastic deformation. Moreover, both types of models allow to control the rigidity and by that the degree of restructuring. The first type of model is computationally more efficient at low fractional dimensions of the aggregates, while the second gives easy access to local shear forces, which is important when breaking of agglomerates is to be considered. As example applications, we reproduce the well-known diffusion-limited agglomeration (DLA) and report results on soot aggregation.

Gizem Inci; Axel Arnold; Andreas Kronenburg; Rudolf Weeber

2014-04-29

167

Agglomeration in solid rocket propellants: novel experimental and modeling methods  

NASA Astrophysics Data System (ADS)

Metal agglomeration is a key factor affecting the performance of metalized solid propellant rockets since many of the mechanisms that degrade specific impulse can be ascribed to metal powder aggregation and agglomeration. Condensed combustion products are generated at or near the burning surface of the propellant and then released in the gas phase where they are shaped by the core flow viscous forces and oxidized by the reactive environment. On this basis, detailed information about the size of agglomerates as they are generated from the propellant may improve the knowledge of the core flow and, thus, the prediction of its effects (namely, two-phase flow losses). This topic entails both modeling and experimental activities, and the aim of this work is to present some recent developments achieved at the Space Propulsion Laboratory in cooperation with other international institutions. The experimental part shows the application of high-speed and high-resolution imaging of propellant combustion for automated measurement of particle size exploited by means of an ad-hoc image processing tool. The modeling part demonstrates how heterogeneity can explain the agglomeration by means of a pocket model using spatial statistics and two- (2D) or threedimensional (3D) virtual propellants. A definition of a characteristic time that fits the agglomeration data for tested propellants is suggested, and a method for predicting the agglomerate size is given. Both activities are still a matter of research but the maturity level reached so far permits the application in some practical cases.

Maggi, F.; Bandera, A.; De Luca, L. T.; Thoorens, V.; Trubert, J. F.; Jackson, T. L.

2011-10-01

168

Novel Binders and Methods for Agglomeration of Ore  

SciTech Connect

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 will 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.

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

2004-03-31

169

Agglomeration processes sustained by dust density waves in Ar/C2H2 plasma: From C2H2 injection to the formation of an organized structure  

NASA Astrophysics Data System (ADS)

In this paper, an experimental investigation of dust particle agglomeration in a capacitively coupled RF discharge is reported. Carbonaceous particles are produced in an argon plasma using acetylene. As soon as the particle density becomes sufficient, dust density waves (DDWs) are spontaneously excited within the cathode sheath. Recently, it was proven that DDWs can significantly enhance the agglomeration rate between particles by transferring them a significant kinetic energy. Thus, it helps them to overcome Coulomb repulsion. The influence of this mechanism is studied from acetylene injection to the formation of very large agglomerates forming an organized structure after a few dozens of seconds. For this purpose, three diagnostic tools are used: extinction measurements to probe nanometer-sized particles, fast imaging for large agglomerates and a dust extraction technique developed for ex-situ analysis.

Dap, Simon; Hugon, Robert; Lacroix, David; de Poucques, Ludovic; Briancon, Jean-Luc; Bougdira, Jamal

2013-03-01

170

Colloidal stability of coal-simulated suspensions in selective agglomeration  

SciTech Connect

A coal suspension was simulated by using graphite to simulate the carbonaceous fraction and kaolinite clay to simulate the ash fraction. Separate studies on each material established their response to additions of oxidized pyrite (ferrous sulfate) and a humic acid simulate (salicylic acid) in terms of zeta potentials profiles with pH and Ionic strength. Concentrations of iron and salicylic acid evaluated were 4.5 {times} 10{sup {minus}3} M and 2.0 {times} 10{sup {minus}4} M, respectively. The zeta potentials profiles of graphite, clay and hexadecane were negative throughout the pH ranges studied. The addition of iron lowered the zeta potentials all of the suspensions under all pH and ionic strength conditions. Salicylic acid decreased the graphite and hexadecane zeta potentials but had no effect on the clay zeta potential profiles. Agglomeration of graphite with bridging liquid shows distinct time dependent rate mechanisms, a initial growth of graphite agglomerates followed by consolidation phase. Graphite agglomeration was rapid with the maximum amount of agglomerate volume growth occurring in under 2-4 minutes. Agglomeration in the first two minutes was characterized by a 1st order rate mechanism. The presence of either Iron and salicylic acid generally improved the first order rates. The addition of clay also improved the first order rates except in the presence of salicylic acid. Heteroagglomeration of graphite with clay was found by hydrodynamic arguments to be unfavored. A multicomponent population balance model which had been developed for evaluating collision efficiencies of coal, ash and pyrite selective agglomeration was evaluated to explain these results. The growth and consolidation characteristics of graphite agglomeration for the experimental conditions examined herein revealed the limitations of such as model for this application.

Schurger, M.L.

1989-01-01

171

An improved technique for modeling initial reservoir hydrocarbon saturation distributions: Applications in Illinois (USA) aux vases oil reservoirs  

USGS Publications Warehouse

An improved technique for modeling the initial reservoir hydrocarbon saturation distributions is presented. In contrast to the Leverett J-function approach, this methodology (hereby termed flow-unit-derived initial oil saturation or FUSOI) determines the distributions of the initial oil saturations from a measure of the mean hydraulic radius, referred to as the flow zone indicator (FZI). FZI is derived from porosity and permeability data. In the FUSOI approach, capillary pressure parameters, S(wir), P(d), and ??, derived from the Brooks and Corey (1966) model [Brooks, R.H., Corey, A.T., 1966. Hydraulic properties of porous media, Hydrology Papers, Colorado State Univ., Ft. Collins, No. 3, March.], are correlated to the FZI. Subsequent applications of these parameters then permit the computation of improved hydrocarbon saturations as functions of FZI and height above the free water level (FWL). This technique has been successfully applied in the Mississippian Aux Vases Sandstone reservoirs of the Illinois Basin (USA). The Aux Vases Zeigler field (Franklin County, IL, USA) was selected for a field-wide validation of this FUSOI approach because of the availability of published studies. With the initial oil saturations determined on a depth-by-depth basis in cored wells, it was possible to geostatistically determine the three-dimensional (3-D) distributions of initial oil saturations in the Zeigler field. The original oil-in-place (OOIP), computed from the detailed initialization of the 3-D reservoir simulation model of the Zeigler field, was found to be within 5.6% of the result from a rigorous material balance method.An improved technique for modeling the initial reservoir hydrocarbon saturation distributions is presented. In contrast to the Leverett J-function approach, this methodology (hereby termed flow-unit-derived initial oil saturation or FUSOI) determines the distributions of the initial oil saturations from a measure of the mean hydraulic radius, referred to as the flow zone indicator (FZI). FZI is derived from porosity and permeability data. In the FUSOI approach, capillary pressure parameters, Swir, Pd, and ??, derived from the Brooks and Corey (1966) model, are correlated to the FZI. Subsequent applications of these parameters then permit the computation of improved hydrocarbon saturations as functions of FZI and height above the free water level (FWL). This technique has been successfully applied in the Mississippian Aux Vases Sandstone reservoirs of the Illinois Basin (USA). The Aux Vases Zeigler field (Franklin County, IL, USA) was selected for a field-wide validation of this FUSOI approach because of the availability of published studies. With the initial oil saturations determined on a depth-by-depth basis in cored wells, it was possible to geostatistically determine the three-dimensional (3-D) distributions of initial oil saturations in the Zeigler field. The original oil-in-place (OOIP), computed from the detailed initialization of the 3-D reservoir simulation model of the Zeigler field, was found to be within 5.6% of the result from a rigorous material balance method.

Udegbunam, E.; Amaefule, J. O.

1998-01-01

172

Microbiological techniques for paraffin reduction in producing oil wells: Final report  

SciTech Connect

Alpha Environmental has completed an eighteen month field oriented, cooperative research program with the US Department of Energy to demonstrate a new economically viable process using petroleum degrading microorganisms, a biocatalyst, formation water and inorganic nutrients to recover residual oil from reservoirs. Alpha's mixed community of microorganisms decomposes crude oil to produce detergents, CO/sub 2/, and new cells, thus mechanically and chemically releasing oil from reservoir pores. The naturally-occurring bacteria utilized in this project were previously selected by screening and isolating microorganisms from soils contaminated with crude oil and petroleum products. The activity and level of salt tolerance (to 20% salinity) of the bacteria is enhanced by a biocatalyst, previously developed by Alpha Environmental. Field evidence suggests that the biocatalyst provides catalytic oxygen to the microorganisms in the reservoir, which augments low levels of in-situ molecular oxygen. 25 refs., 10 figs., 6 tabs.

Oppenheimer, C.H.; Hiebert, F.K.

1989-04-01

173

Advanced physical fine coal cleaning spherical agglomeration. Final report  

SciTech Connect

The project included process development, engineering, construction, and operation of a 1/3 tph proof-of-concept (POC) spherical agglomeration test module. The POC tests demonstrated that physical cleaning of ultrafine coal by agglomeration using heptane can achieve: (1) Pyritic sulfur reductions beyond that possible with conventional coal cleaning methods; (2) coal ash contents below those which can be obtained by conventional coal cleaning methods at comparable energy recoveries; (3) energy recoveries of 80 percent or greater measured against the raw coal energy content; (4) complete recovery of the heptane bridging liquid from the agglomerates; and (5) production of agglomerates with 3/8-inch size and less than 30 percent moisture. Test results met or exceeded all of the program objectives. Nominal 3/8-inch size agglomerates with less than 20 percent moisture were produced. The clean coal ash content varied between 1.5 to 5.5 percent by weight (dry basis) depending on feed coal type. Ash reductions of the run-of-mine (ROM) coal were 77 to 83 percent. ROM pyritic sulfur reductions varied from 86 to 90 percent for the three test coals, equating to total sulfur reductions of 47 to 72 percent.

Not Available

1990-09-01

174

Combined analysis of the root bark oil of Cleistopholis glauca by chromatographic and spectroscopic techniques.  

PubMed

The composition of root bark oil from Cleistopholis glauca Pierre ex Engler & Diels growing wild in Ivory Coast was investigated by GC (in combination with retention indices) and "3C NMR spectroscopy after partition o f hydrocarbons a nd oxygenated compounds on silica g el. Thirty-one compounds havebeen identified. C. glauca produces a sesquiterpene-rich oil, patchoulenone (33.5%), cyperene (9.5%) and germacrene D (6.6%) being the main components. Special attention was paid to the identification and quantification ofgermacrene C (a heat-sensitive compound) and &-elemene, which were achieved by a combination of GC(FID) and 13C NMR spectroscopy. The composition of C. glauca root bark and leaf oils differed drastically. PMID:24555297

Ouattar, Zana A; Boti, Jean Brice; Ahibo, Coffy Antoine; Tomi, Félix; Casanova, Joseph; Bighelli, Ange

2013-12-01

175

Use of fly ash agglomerates for removal of arsenic.  

PubMed

The aim of this work is to investigate the application of fly ash adsorbent for removal of arsenite ions from dilute solution (100-1,000 ppm). Experiments were carried out using material from the "Turów" (Poland) brown-coal-burning power plant, which was wetted, then mixed and tumbled in a granulator to form spherical agglomerates. Measurements of arsenic adsorption from aqueous solution were carried out at room temperature and natural pH of fly ash agglomerates, in either a shaken flask or circulating column, to compare two different methods of contacting solution with adsorbent. Adsorption isotherms of arsenic were determined for agglomerated material using the Freundlich equation. Kinetic studies indicated that sorption follows a pseudo-second-order model. Preferable method to carry out the process is continuous circulation of arsenite solution through a column. PMID:20383564

Polowczyk, Izabela; Bastrzyk, Anna; Ko?lecki, Tomasz; Sawi?ski, Wojciech; Rudnicki, Piotr; Soko?owski, Adam; Sadowski, Zygmunt

2010-08-01

176

Increased Oil Production and Reserves Utilizing Secondary/Tertiary Recovery Techniques on Small Reservoirs in the Paradox Basin, Utah  

SciTech Connect

The primary objective of this project is to enhance domestic petroleum production by field demonstration and technology transfer of an advanced- oil-recovery technology in the Paradox basin, southeastern Utah. If this project can demonstrate technical and economic feasibility, the technique can be applied to approximately 100 additional small fields in the Paradox basin alone, and result in increased recovery of 150 to 200 million barrels (23,850,000-31,800,000 m3) of oil. This project is designed to characterize five shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation and choose the best candidate for a pilot demonstration project for either a waterflood or carbon-dioxide-(CO2-) miscible flood project. The field demonstration, monitoring of field performance, and associated validation activities will take place within the Navajo Nation, San Juan County, Utah.

Jr., Chidsey, Thomas C.; Allison, M. Lee

1999-11-02

177

Increased Oil Production and Reserves Utilizing Secondary/Terriary Recovery Techniques on Small Reservoirs in the Paradox Basin, Utah  

SciTech Connect

The primary objective of this project is to enhance domestic petroleum production by demonstration and technology transfer of an advanced oil recovery technology in the Paradox basin, southeastern Utah. If this project can demonstrate technical and economic feasibility, the technique can be applied to about 100 additional small fields in the Paradox basin alone, and result in increased recovery of 150 to 200 million barrels of oil. This project is designed to characterize five shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation and choose the best candidate for a pilot demonstration project for either a waterflood or carbon dioxide-(CO -) 2 flood project. The field demonstration, monitoring of field performance, and associated validation activities will take place in the Paradox basin within the Navajo Nation. Two activities continued this quarter as part of the geological and reservoir characterization of productive carbonate buildups in the Paradox basin: (1) diagenetic characterization of project field reservoirs, and (2) technology transfer.

David E. Eby; Thomas C. Chidsey, Jr.

1998-04-08

178

Increased Oil Production and Reserves Utilizing Secondary/Tertiary Recovery Techniques on Small Reservoirs in the Paradox Basin, Utah  

SciTech Connect

The primary objective of this project was to enhance domestic petroleum production by field demonstration and technology transfer of an advanced-oil-recovery technology in the Paradox Basin, southeastern Utah. If this project can demonstrate technical and economic feasibility, the technique can be applied to approximately 100 additional small fields in the Paradox Basin alone, and result in increased recovery of 150 to 200 million barrels (23,850,000-31,800,000 m3) of oil. This project was designed to characterize five shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation and choose the best candidate for a pilot demonstration project for either a waterflood or carbon-dioxide-(CO2-) miscible flood project. The field demonstration, monitoring of field performance, and associated validation activities will take place within the Navajo Nation, San Juan County, Utah.

Chidsey Jr., Thomas C.

2003-02-06

179

Application of Rosenbrock search technique to reduce the drilling cost of a well in Bai-Hassan oil field  

SciTech Connect

The powerful Rosenbrock search technique, which optimizes both the search directions using the Gram-Schmidt procedure and the step size using the Fibonacci line search method, has been used to optimize the drilling program of an oil well drilled in Bai-Hassan oil field in Kirkuk, Iran, using the twodimensional drilling model of Galle and Woods. This model shows the effect of the two major controllable variables, weight on bit and rotary speed, on the drilling rate, while considering other controllable variables such as the mud properties, hydrostatic pressure, hydraulic design, and bit selection. The effect of tooth dullness on the drilling rate is also considered. Increasing the weight on the drill bit with a small increase or decrease in ratary speed resulted in a significant decrease in the drilling cost for most bit runs. It was found that a 48% reduction in this cost and a 97-hour savings in the total drilling time was possible under certain conditions.

Aswad, Z.A.R.; Al-Hadad, S.M.S.

1983-03-01

180

Continuous air agglomeration method for high carbon fly ash beneficiation  

DOEpatents

The carbon and mineral components of fly ash are effectively separated by a continuous air agglomeration method, resulting in a substantially carboree mineral stream and a highly concentrated carbon product. The method involves mixing the fly ash comprised of carbon and inorganic mineral matter with a liquid hydrocarbon to form a slurry, contacting the slurry with an aqueous solution, dispersing the hydrocarbon slurry into small droplets within the aqueous solution by mechanical mixing and/or aeration, concentrating the inorganic mineral matter in the aqueous solution, agglomerating the carbon and hydrocarbon in the form of droplets, collecting the droplets, separating the hydrocarbon from the concentrated carbon product, and recycling the hydrocarbon.

Gray, McMahon L. (Pittsburgh, PA); Champagne, Kenneth J. (Monongahela, PA); Finseth, Dennis H. (Pittsburgh, PA)

2000-01-01

181

Anesthesia and liver biopsy techniques for pigeon guillemots (Cepphus columba) suspected of exposure to crude oil in marine environments  

USGS Publications Warehouse

This paper reports on the anesthesia and liver biopsy techniques used in adult and nestling pigeon guillemots (Cepphus columba) to test for continued exposure to residual crude oil in the marine environment. Populations of pigeon guillemots have declined significantly in Prince William Sound, Alaska, USA, possibly because of residual effects of crude oil in the environment after the Exxon Valdez oil spill in March 1989. Measurement of hepatic cytochrome P450 1A (CYP1A) is currently the best way to assess crude oil exposure from food sources; however, lethal sampling to obtain adequate liver tissue was not desirable in this declining population of birds. As part of a larger study to identify factors limiting the recovery of pigeon guillemots and other seabird populations, we surgically collected liver samples from adult and nestling guillemots to provide samples for measurement of hepatic CYP1A concentrations. Results from the larger study were reported elsewhere. Liver samples were taken from 26 nestling (1998) and 24 adult (1999) guillemots from a previously oiled site (Naked Island; 12 chicks, 13 adults) and from a nonoiled site (Jackpot Island/Icy Bay; 14 chicks, 11 adults). The birds were anesthetized with isoflurane. No surgical complications occurred with any of the birds and all adult and nestling birds survived after surgery to the point of release or return to the nest. Thirteen out of 14 chicks from the Jackpot Island/Icy Bay and 8 out of 12 chicks from Naked Island fledged. Four chicks at Naked Island were depredated before fledging. All adults abandoned their nests after surgery, so the study sites were revisited the following summer (2000) in an attempt to assess overwinter survival of the adults. All but 1 adult biopsied bird at the nonoiled site (Icy Bay) was found renesting, whereas only 2 birds at the previously oiled site (Naked Island) were similarly observed. The percent of 1999 breeders at Naked Island that returned to their nest sites to breed again in 2000 was low at nests of biopsied birds and nonbiopsied birds alike, suggesting that factors other than the surgical procedure were responsible for the low return rate among this group. These survival results provide strong support lot using experienced veterinarians for nonlethal invasive sample collection from birds to document exposure to crude oil in the marine environment.

Degernes, L.A.; Harms, C.A.; Golet, G.H.; Mulcahy, D.M.

2002-01-01

182

Agglomeration in Green Cities? :Emergence of Recycling Market  

Microsoft Academic Search

This paper examines the impact of garbage (municipal wastes) on the agglomeration econ- omy. Waste is proportionately generated from consumption and is charged disposal cost. This paper shows the conditions for emergence of recycling market, according to the shape of dis- posal cost function respect to the regional population. In reality disposal costs may depend on its region's characteristics. Our

Kenmei Tsubota

183

Alternating electric field induced agglomeration of carbon black filled resins  

Microsoft Academic Search

This letter reports on our observation that an alternating electric field is able to induce the formation of an electrically conducting network in carbon black (CB) filled resins well below the zero-field percolation threshold. Compared with the recently presented dc method, the ac agglomeration is more efficient in two respects: it proceeds significantly faster under equivalent conditions and is still

Matthias-Klaus Schwarz; Wolfgang Bauhofer; Karl Schulte

2002-01-01

184

Preventing ash agglomeration during gasification of high-sodium lignite  

Microsoft Academic Search

Various additives were evaluated to assess their ability to prevent ash agglomeration during the gasification of high-sodium lignite. Additives that showed promise in simple muffle furnace tests included meta-kaolin, vermiculite, two types of silica fume, and one type of bauxite. Additives that were tested and rejected included dolomite, calcite, sand flour, kaolinite, fine kaolin, and calcined bauxite. Based on the

Robert S. Dahlin; Johnny R. Dorminey; WanWang Peng; Roxann F. Leonard; Pannalal Vimalchand

2009-01-01

185

Experimental study and modeling of fluidized bed coating and agglomeration  

Microsoft Academic Search

This work deals with the fluidized bed coating and agglomeration of solid particles. The effect of particle size on coating criteria was investigated using sand particles as the coating support and aqueous solutions containing NaCl as coating liquid. The results showed that both growth rate and efficiency increase with decreasing the particle size. The growth was mainly governed by layering

K. Saleh; D. Steinmetz; M. Hemati

2003-01-01

186

MULTIPLICITY AND STABILITY ANALYSIS OF AGGLOMERATION CONTROLLED PRECIPITATION  

Microsoft Academic Search

The possibility of multiplicity in continuous isothermal MSMPR precipitators has been explored for agglomeration controlled conditions and general criteria, independent of nucleation kinetics, are developed for stability and multiplicity of the steady states. For the Volmer model of primary nucleation and the magma dependent power law model of secondary nucleation, parameter regions are determined in which multiple steady states exist,

B. K. PADIA; S. K. BHATIA

1991-01-01

187

Sonic agglomeration of ammonium chloride aerosols in intense sound fields  

NASA Astrophysics Data System (ADS)

Acoustic coagulations were studied under traveling-wave conditions with the sonic intensity levels ranging from 145 to 1556 dB and frequencies from 600 to 3000 Hz. The aerosols used ammonium chloride with mass concentrations of 2-20 gm/cm/and sizes from 0.06 to 35 micrometers. Experimental results show a bimodal mass distribution for the acoustically agglomerated particles. The agglomeration increases with the sonic frequency, the intensity, the particle size and the mass loading. The acoustic kernels were numerically evaluated scheme was developed, tested, and used to calculate the mass distribution of the acoustically agglomerated particles. A comparison of the experiment with theory shows that the orthokinetic interaction is the dominant mechanism under all the experimental conditions in this study. When the total number of coarse particles (collectors) is small, the measured mass distributions of the agglomerated particles are in good agreement with the numerical calculation. Once the number of collectors becomes large, the experimental data is lower than that as calculated by the theory.

Cheng, M. T.

188

Regional Disparities in the European Union: Convergence and Agglomeration  

Microsoft Academic Search

Economic disparities between the regions of the European Union are of constant concern both for policy and economic research. In this paper we examine whether there are overlapping trends of regional development in the EU: overall convergence on the one hand and persistent or even increasing spatial concentration (agglomeration) on the other. Kernel density estimation, Markov chain analysis and cross-sectional

Kurt Geppert; Michael Happich; Andreas Stephan

2005-01-01

189

Langevin agglomeration of nanoparticles interacting via a central potential  

Microsoft Academic Search

Nanoparticle agglomeration in a quiescent fluid is simulated by solving the Langevin equations of motion of a set of interacting monomers in the continuum regime. Monomers interact via a radial rapidly decaying intermonomer potential. The morphology of generated clusters is analyzed through their fractal dimension df and the cluster coordination number. The time evolution of the cluster fractal dimension is

Lorenzo Isella; Yannis Drossinos

2010-01-01

190

Regional disparities in the European Union: Convergence and agglomeration  

Microsoft Academic Search

Economic disparities between the regions of the European Union are of constant concern both for policy and economic research. In this paper, we examine whether there are overlapping trends of regional development in the EU: overall convergence, on the one hand, and persistent or even increasing spatial concentration (agglomeration), on the other. Kernel density estimation, Markov chain analysis and cross-sectional

Kurt Geppert; Andreas Stephan

2008-01-01

191

The isolation of hydroxy acids from lesquerella oil lipolysate by a saponification\\/extraction technique  

Microsoft Academic Search

The lipolysate from immobilizedRhizomucor miehei lipase (Lipozyme\\u000a tm\\u000a )-catalyzed hydrolysis of lesquerella oil contains typically 35% free fatty acid (FFA), 2% monoglyceride, 25% diglyceride\\u000a (DG), and 38% triglyceride (TG). Of the FFA, 75–80% are hydroxy acids (HFA). Various methods for isolating HFA from the lipolysate\\u000a were examined, and a novel saponification\\/extraction method was developed. Lipolysate was mixed with 4 vol

Douglas G. Hayes; Kenneth D. Carlson; Robert Kleiman

1996-01-01

192

Combustion characteristics of lignite and oil shale samples by thermal analysis techniques  

Microsoft Academic Search

In this research thermal analysis and kinetics of ten lignite's and two oil shale samples of different origin were performed\\u000a using a TA 2960 thermal analysis system with thermogravimetry (TG\\/DTG) and differential al analysis (DTA) modules. Experiments\\u000a were performed with a sample size of ~10 mg, heating rate of 10C min-1. Flow rate was kept constant (10 L h-1) in

M. V. Kök; G. Pokol; C. Keskin; J. Madarász; S. Bagci

2004-01-01

193

Continuous subcritical water extraction of medicinal plant essential oil: comparison with conventional techniques  

Microsoft Academic Search

A subcritical extractor equipped with a three-way inlet valve and an on\\/off outlet valve has been used for performing subcritical water extractions (SWE) in a continuous manner for the isolation of the essential oil of fennel, a medicinal plant. The target compounds were removed from the aqueous extract by a single extraction with 5 ml hexane, determined by gas-chromatography-flame ionization

L Gámiz-Gracia; M. D Luque de Castro

2000-01-01

194

A Landfarming Application Technique Used as Environmental Remediation for Coal Oil Pollution  

Microsoft Academic Search

Since the massive exploitation of the Val d'Agri (Basilicata-Italy) oilfield has started, a lot of environmental pollution accidents have occurred in the same region. This research takes as starting point the heavy accident occurred in the year 2000, when 15,150 kg of coal oil were spilt all over the Agri river bed and the surrounding fields. In that particular case, the

Concetta I. Giasi; Annalisa Morelli

2003-01-01

195

Monitoring of olive oil mills' wastes using electrical resistivity tomography techniques  

NASA Astrophysics Data System (ADS)

Olive oil mills' wastes (OOMW) are one of the byproducts of the oil production that can lead to serious environmental pollution when they are deposited in ponds dug on the ground surface. Electrical Resistivity Tomography (ERT) method can provide a valuable tool in order to monitor through time the physical flow of the wastes into the subsurface. ERT could potentially locate the electrical signature due to lower resistivity values resulting from the leakage of OOMW to the subsurface. For this purpose, two vertical boreholes were installed (12m depth, 9 m apart) in the vicinity of an existing pond which is filled with OOMW during the oil production period. The test site is situated in Saint Andreas village about 15km south of the city of Rethymno (Crete, Greece). Surface ERT measurements were collected along multiple lines in order to reconstruct the subsurface resistivity models. Data acquisition was performed with standard and optimized electrode configuration protocols. The monitoring survey includes the ERT data collection for a period of time. The study was initiated before the OOMW were deposited in the pond, so resistivity fluctuations are expected due to the flow of OOMW in the porous subsurface media through time. Preliminary results show the good correlation of the ERT images with the drilled geological formations and the identification of low resistivity subsurface zone that could be attributed to the flow of the wastes within the porous layers.

Simyrdanis, Kleanthis; Papadopoulos, Nikos; Kirkou, Stella; Sarris, Apostolos; Tsourlos, Panagiotis

2014-08-01

196

Experimental study on static and impact strength of sintered agglomerates  

NASA Astrophysics Data System (ADS)

Porous internal structure is common among small bodies in the planetary systems and possible range of porosity, strength, and scale of in-homogeneity is wide. Icy agglomerates, such as icy dust aggregates in the proto-planetary disks or icy re-accumulated bodies of fragments from impact disruption beyond snow-line would have stronger bulk strength once the component particles physically connect each other due to sintering. In this study, in order to get better understanding of impact disruption process of such bodies, we first investigated the critical tensile (normal) and bending (tangential) forces to break a single neck, the connected part of the sintered particles, using sintered dimer of macro glass particles of ˜5 mm in diameter. We found that the critical tensile force is proportional to the cross-section of the neck when the neck grows sufficiently larger than the surface roughness of the original particles. We also found that smaller force is required to break a neck when the force is applied tangentially to the neck than normally applied. Then we measured the bulk tensile strength of sintered glass agglomerates consisting of 90 particles and showed that the average tensile stress to break a neck of agglomerates in static loading is consistent with the measured value for dimers. Impact experiments with velocity from 40 to 280 m/s were performed for the sintered agglomerates with ˜40% porosity, of two different bulk tensile strengths. The size ratio of the beads to the target was 0.19. The energy density required to catastrophically break the agglomerate was shown to be much less than those required for previously investigated sintered glass beads targets with ˜40% porosity, of which the size of component bead is 10 -2 times smaller and the size ratio of the bead to target is also ˜10 -2 times smaller than the agglomerates in this study. This is probably due to much smaller number of necks for the stress wave to travel through the agglomerates and therefore the energy dissipation at the necks is minimal. Also, the much larger fraction of the surface particles enables the particles to move more freely and thus be broken more easily. The catastrophic disruption of the agglomerates is shown to occur when the projectile kinetic energy is a few times of the total energy to break all of the necks of the agglomerates. The result implies that finer fragments from sintered agglomerates may have smaller catastrophic disruption energy threshold for shattering (QS?) than other larger fragments with similar porosity and bulk tensile strength but much larger number of constituent particles. If this is the case, size-dependence of QS? (smaller is weaker) is opposite to those usually considered for the bodies in the strength regime.

Machii, Nagisa; Nakamura, Akiko M.

2011-01-01

197

A model for transport and agglomeration of particles in reactive ion etching plasma reactors  

E-print Network

importance on understanding particle growth and agglomeration mechanisms. Since individual particles is that primary particles grow to a terminal size, and then agglomerate to form larger structures. The agglom

Kushner, Mark

198

Effect of coal particle size distribution on agglomerate formation in a fluidized bed combustor (FBC)  

Microsoft Academic Search

An investigation was conducted to find out the reasons for agglomeration in a fluidized bed combustion (FBC) power plant. Two typical coal samples were collected for investigation. The first sample was collected when the plant was operating smoothly, and the second was collected immediately after agglomeration. These two samples were subjected to analysis. It was observed that agglomeration of the

G. Venkat Reddy; S. K. Mahapatra

1999-01-01

199

Simulation of agglomeration reactors via a coupled CFD\\/direct Monte-Carlo method  

Microsoft Academic Search

The present study deals with simulation of agglomeration reactors, based on a CFD calculation method for describing the turbulent flow field, coupled with a direct Monte-Carlo method for the agglomeration process. The potentiality of stochastic methods, well suited for simulation of spherical agglomeration where complex kernels have to take into account the effects of the particles size and of the

L. Madec; L. Falk; E. Plasari

2001-01-01

200

A macroscopic agglomeration kernel model for gibbsite precipitation in turbulent and laminar flows  

Microsoft Academic Search

A macroscopic agglomeration kernel model has been developed that is capable of describing gibbsite agglomeration over a broad range of process conditions, including both the laminar and turbulent flow regimes. The agglomeration kernel model was derived using chemical reaction engineering principles and data from an extensive experimental program covering a wide range of temperatures, supersaturations, seed sizes, shear rates and

I. Livk; D. Ilievski

2007-01-01

201

Applying monitoring, verification, and accounting techniques to a real-world, enhanced oil recovery operational CO2 leak  

USGS Publications Warehouse

The use of carbon dioxide (CO2) for enhanced oil recovery (EOR) is being tested for oil fields in the Illinois Basin, USA. While this technology has shown promise for improving oil production, it has raised some issues about the safety of CO2 injection and storage. The Midwest Geological Sequestration Consortium (MGSC) organized a Monitoring, Verification, and Accounting (MVA) team to develop and deploy monitoring programs at three EOR sites in Illinois, Indiana, and Kentucky, USA. MVA goals include establishing baseline conditions to evaluate potential impacts from CO2 injection, demonstrating that project activities are protective of human health and the environment, and providing an accurate accounting of stored CO2. This paper focuses on the use of MVA techniques in monitoring a small CO2 leak from a supply line at an EOR facility under real-world conditions. The ability of shallow monitoring techniques to detect and quantify a CO2 leak under real-world conditions has been largely unproven. In July of 2009, a leak in the pipe supplying pressurized CO2 to an injection well was observed at an MGSC EOR site located in west-central Kentucky. Carbon dioxide was escaping from the supply pipe located approximately 1 m underground. The leak was discovered visually by site personnel and injection was halted immediately. At its largest extent, the hole created by the leak was approximately 1.9 m long by 1.7 m wide and 0.7 m deep in the land surface. This circumstance provided an excellent opportunity to evaluate the performance of several monitoring techniques including soil CO2 flux measurements, portable infrared gas analysis, thermal infrared imagery, and aerial hyperspectral imagery. Valuable experience was gained during this effort. Lessons learned included determining 1) hyperspectral imagery was not effective in detecting this relatively small, short-term CO2 leak, 2) even though injection was halted, the leak remained dynamic and presented a safety risk concern during monitoring activities and, 3) the atmospheric and soil monitoring techniques used were relatively cost-effective, easily and rapidly deployable, and required minimal manpower to set up and maintain for short-term assessments. However, characterization of CO2 distribution near the land surface resulting from a dynamic leak with widely variable concentrations and fluxes was challenging. ?? 2011 Published by Elsevier Ltd.

Wimmer, B.T.; Krapac, I.G.; Locke, R.; Iranmanesh, A.

2011-01-01

202

A numerical/empirical technique for history matching and predicting cyclic steam performance in Canadian oil sands reservoirs  

NASA Astrophysics Data System (ADS)

The oil sands of Alberta contain some one trillion barrels of bitumen-in-place, most contained in the McMurray, Wabiskaw, Clearwater, and Grand Rapids formations. Depth of burial is 0--550 m, 10% of which is surface mineable, the rest recoverable by in-situ technology-driven enhanced oil recovery schemes. To date, significant commercial recovery has been attributed to Cyclic Steam Stimulation (CSS) using vertical wellbores. Other techniques, such as Steam Assisted Gravity Drainage (SAGD) are proving superior to other recovery methods for increasing early oil production but at initial higher development and/or operating costs. Successful optimization of bitumen production rates from the entire reservoir is ultimately decided by the operator's understanding of the reservoir in its original state and/or the positive and negative changes which occur in oil sands and heavy oil deposits upon heat stimulation. Reservoir description is the single most important factor in attaining satisfactory history matches and forecasts for optimized production of the commercially-operated processes. Reservoir characterization which lacks understanding can destroy a project. For example, incorrect assumptions in the geological model for the Wolf Lake Project in northeast Alberta resulted in only about one-half of the predicted recovery by the original field process. It will be shown here why the presence of thin calcite streaks within oil sands can determine the success or failure of a commercial cyclic steam project. A vast amount of field data, mostly from the Primrose Heavy Oil Project (PHOP) near Cold Lake, Alberta, enabled the development a simple set of correlation curves for predicting bitumen production using CSS. A previously calibtrated thermal numerical simulation model was used in its simplist form, that is, a single layer, radial grid blocks, "fingering" or " dilation" adjusted permeability curves, and no simulated fracture, to generate the first cycle production correlation curves. The key reservoir property used to develop a specific curve was to vary the initial mobile water saturation. Individual pilot wells were then history-matched using these correlation curves, adjusting for thermal net pay using perforation height and a fundamentally derived "net pay factor". Operating days (injection plus production) were required to complete the history matching calculations. Subsequent cycles were then history-matched by applying an Efficiency Multiplication Factor (EMF) to the original first cycle prediction method as well as selecting the proper correlation curve for the specific cycle under analysis by using the appropriate steam injection rates and slug sizes. History matches were performed on eight PHOP wells (two back-to-back, five-spot patterns) completed in the Wabiskaw and, three single-well tests completed just below in the McMurray Formation. Predictions for the PHOP Wabiskaw Formation first cycle bitumen production averaged within 1% of the actual pilot total. Bitumen recovery from individual wells for second cycle onwards, was within 20% of actual values. For testing the correlations, matching was also performed on cyclic steam data from British Petroleum's Wolf Lake Project, the Esso Cold Lake Project, and the PCEJ Fort McMurray Pilot, a joint venture of Petro-Canada, Cities Services (Canadian Occidental), Esso, and Japan-Canada Oil Sands with reasonable results.

Leshchyshyn, Theodore Henry

203

Continuous subcritical water extraction of medicinal plant essential oil: comparison with conventional techniques.  

PubMed

A subcritical extractor equipped with a three-way inlet valve and an on/off outlet valve has been used for performing subcritical water extractions (SWE) in a continuous manner for the isolation of the essential oil of fennel, a medicinal plant. The target compounds were removed from the aqueous extract by a single extraction with 5 ml hexane, determined by gas-chromatography-flame ionization (GC-FID) and identified by mass spectrometry (MS). The proposed extraction method has been compared with both hydrodistillation and dichloromethane manual extraction. Better results have been obtained with the proposed method in terms of rapidity, efficiency, cleanliness and possibility of manipulating the composition of the extract. PMID:18967949

Gámiz-Gracia, L; Luque de Castro, M D

2000-05-01

204

Bioremediation of Crude Oil-Contaminated Soil Using Slurry-Phase Biological Treatment and Land Farming Techniques  

Microsoft Academic Search

Field-scale experiments on bioremediation of soil heavily contaminated with crude oil were undertaken on the territory of the Kokuyskoye oil field (Perm region, West Urals, Russia) owned by the LUKOIL Company. The pollution consisted of the contents of a oil waste storage pit, which mostly received soils contaminated after accidental oil spills and also the solid n-alkane (paraffin) wastes removed

Maria S. Kuyukina; Irena B. Ivshina; Marina I. Ritchkova; James C. Philp; Colin J. Cunningham; Nick Christofi

2003-01-01

205

Preventing ash agglomeration during gasification of high-sodium lignite  

SciTech Connect

Various additives were evaluated to assess their ability to prevent ash agglomeration during the gasification of high-sodium lignite. Additives that showed promise in simple muffle furnace tests included meta-kaolin, vermiculite, two types of silica fume, and one type of bauxite. Additives that were tested and rejected included dolomite, calcite, sand flour, kaolinite, fine kaolin, and calcined bauxite. Based on the muffle furnace test results, the meta-kaolin was selected for a follow-on demonstration in a pilot-scale coal gasifier. Pilot-scale testing showed that the addition of coarse (minus 14-mesh, 920-{mu}m mean size) meta-kaolin at a feed rate roughly equivalent to the ash content of the lignite (10 wt %) successfully prevented agglomeration and deposition problems during gasification of high-sodium lignite at a maximum operating temperature of 927{sup o}C (1700{sup o}F). 13 refs., 24 figs., 1 tab.

Robert S. Dahlin; Johnny R. Dorminey; WanWang Peng; Roxann F. Leonard; Pannalal Vimalchand [Southern Research Institute and Southern Company Services, Wilsonville, AL (USA). Power Systems Development Facility

2009-01-15

206

Studies on some zwitterionic surfactant gas hydrate anti-agglomerants  

Microsoft Academic Search

Low dosage hydrate inhibitors (LDHIs) are a recently developed hydrate control technology, which can be more cost-effective than traditional practices such as the use of thermodynamic inhibitors e.g. methanol and glycols. Two classes of LDHI called kinetic inhibitors (KHIs) and anti-agglomerants (AAs) are already being successfully used in the field. This paper describes efforts to develop new classes of AAs

Malcolm A. Kelland; Thor M. Svartaas; Jorunn Øvsthus; Takashi Tomita; Jun-ichi Chosa

2006-01-01

207

Studies on some alkylamide surfactant gas hydrate anti-agglomerants  

Microsoft Academic Search

Low dosage hydrate inhibitors (LDHIs) are a recently developed hydrate control technology, which can be more cost-effective than traditional practices such as the use of thermodynamic inhibitors e.g., methanol and glycols. Two classes of LDHI called kinetic inhibitors (KHIs) and anti-agglomerants (AAs) are already being successfully used in the field. This paper describes efforts to develop new classes of AA

Malcolm A. Kelland; Thor M. Svartaas; Jorunn Øvsthus; Takashi Tomita; Keiichiro Mizuta

2006-01-01

208

Langevin agglomeration of nanoparticles interacting via a central potential.  

PubMed

Nanoparticle agglomeration in a quiescent fluid is simulated by solving the Langevin equations of motion of a set of interacting monomers in the continuum regime. Monomers interact via a radial rapidly decaying intermonomer potential. The morphology of generated clusters is analyzed through their fractal dimension df and the cluster coordination number. The time evolution of the cluster fractal dimension is linked to the dynamics of two populations: small (k? 15) and large (k>15) clusters. At early times monomer-cluster agglomeration is the dominant agglomeration mechanism (d(f)=2.25) , whereas at late times cluster-cluster agglomeration dominates (d(f)=1.56). Clusters are found to be compact (mean coordination number of ?5), tubular, and elongated. The local compact structure of the aggregates is attributed to the isotropy of the interaction potential, which allows rearrangement of bonded monomers, whereas the large-scale tubular structure is attributed to its relatively short attractive range. The cluster translational diffusion coefficient is determined to be inversely proportional to the cluster mass and the (per-unit-mass) friction coefficient of an isolated monomer, a consequence of the neglect of monomer shielding in a cluster. Clusters generated by unshielded Langevin equations are referred to as ideal clusters because the surface area accessible to the underlying fluid is found to be the sum of the accessible surface areas of the isolated monomers. Similarly, ideal clusters do not have, on average, a preferential orientation. The decrease in the numbers of clusters with time and a few collision kernel elements are evaluated and compared to analytical expressions. PMID:20866617

Isella, Lorenzo; Drossinos, Yannis

2010-07-01

209

Langevin agglomeration of nanoparticles interacting via a central potential  

E-print Network

Nanoparticle agglomeration in a quiescent fluid is simulated by solving the Langevin equations of motion of a set of interacting monomers in the continuum regime. Monomers interact via a radial, rapidly decaying intermonomer potential. The morphology of generated clusters is analyzed through their fractal dimension $d_f$ and the cluster coordination number. The time evolution of the cluster fractal dimension is linked to the dynamics of two populations, small ($k \\le 15$) and large ($k>15$) clusters. At early times monomer-cluster agglomeration is the dominant agglomeration mechanism ($d_f = 2.25$), whereas at late times cluster-cluster agglomeration dominates ($d_f = 1.56$). Clusters are found to be compact (mean coordination number $\\sim 5$), tubular, and elongated. The local, compact structure of the aggregates is attributed to the isotropy of the interaction potential, which allows rearrangement of bonded monomers, whereas the large-scale tubular structure is attributed to its relatively short attractive range. The cluster translational diffusion coefficient is determined to be inversely proportional to the cluster mass and the (per-unit-mass) friction coefficient of an isolated monomer, a consequence of the neglect of monomer shielding in a cluster. Clusters generated by unshielded Langevin equations are referred to as \\textit{ideal clusters} because the surface area accessible to the underlying fluid is found to be the sum of the accessible surface areas of the isolated monomers. Similarly, ideal clusters do not have, on average, a preferential orientation. The decrease of the numbers of clusters with time and a few collision kernel elements are evaluated and compared to analytical expressions.

Lorenzo Isella; Yannis Drossinos

2010-04-26

210

The Emergence of Optimal Agglomeration in Dynamic Economics  

Microsoft Academic Search

We analyze endogenous pattern formation resulting from forward-looking optimizing behavior of economic agents in the presence of spatial spillovers modelled by continuous kernels. We use Fourier methods to identify nec- essary and su�¢ cient conditions for the emergence of optimal agglomeration through an optimal spillover induced instability of a spatially homogeneous steady state. We apply our methods to study the

William Brock; Anastasios Xepapadeas

211

Langevin agglomeration of nanoparticles interacting via a central potential  

NASA Astrophysics Data System (ADS)

Nanoparticle agglomeration in a quiescent fluid is simulated by solving the Langevin equations of motion of a set of interacting monomers in the continuum regime. Monomers interact via a radial rapidly decaying intermonomer potential. The morphology of generated clusters is analyzed through their fractal dimension df and the cluster coordination number. The time evolution of the cluster fractal dimension is linked to the dynamics of two populations: small (k?15) and large (k>15) clusters. At early times monomer-cluster agglomeration is the dominant agglomeration mechanism (df=2.25) , whereas at late times cluster-cluster agglomeration dominates (df=1.56) . Clusters are found to be compact (mean coordination number of ˜5 ), tubular, and elongated. The local compact structure of the aggregates is attributed to the isotropy of the interaction potential, which allows rearrangement of bonded monomers, whereas the large-scale tubular structure is attributed to its relatively short attractive range. The cluster translational diffusion coefficient is determined to be inversely proportional to the cluster mass and the (per-unit-mass) friction coefficient of an isolated monomer, a consequence of the neglect of monomer shielding in a cluster. Clusters generated by unshielded Langevin equations are referred to as ideal clusters because the surface area accessible to the underlying fluid is found to be the sum of the accessible surface areas of the isolated monomers. Similarly, ideal clusters do not have, on average, a preferential orientation. The decrease in the numbers of clusters with time and a few collision kernel elements are evaluated and compared to analytical expressions.

Isella, Lorenzo; Drossinos, Yannis

2010-07-01

212

Langevin agglomeration of nanoparticles interacting via a central potential  

Microsoft Academic Search

Nanoparticle agglomeration in a quiescent fluid is simulated by solving the\\u000aLangevin equations of motion of a set of interacting monomers in the continuum\\u000aregime. Monomers interact via a radial, rapidly decaying intermonomer\\u000apotential. The morphology of generated clusters is analyzed through their\\u000afractal dimension $d_f$ and the cluster coordination number. The time evolution\\u000aof the cluster fractal dimension is

Lorenzo Isella; Yannis Drossinos

2010-01-01

213

Modeling agglomeration processes in fluid-bed granulation  

Microsoft Academic Search

Many agrochemicals are formulated as water dispersive granules through agglomeration, beginning with a fine powder (â¼1 μm) and ending with granules on the order of 500 μm. Powders are charged into a granulation system with a liquid binding agent, and granules are subsequently grown to an appropriate size. Granulation in fluid beds is presented using a mass conserving discretized population

Steven A. Cryer

1999-01-01

214

A Simple, Analytically Solvable, Dual-Space Economic Agglomerations Model  

Microsoft Academic Search

This paper presents a simple, analytically solvable, dual-space economic agglomerations model which, like Krugmann’s model,\\u000a contains two agglomerative forces. However, in contrast to that model, two agglomerative forces are technological externalities\\u000a and transaction costs rather than labor division and transaction costs. Moreover, the present model exhibits ‘learning by\\u000a transacting’ of the technological externalities rather than ‘learning by doing’. This may

Zheng Shi; Zheng Wen; Jin Xia

2010-01-01

215

Effects of Temperature, Time, and Solution on Nanoparticle Agglomeration  

Microsoft Academic Search

Previous studies from our laboratory have shown that the environment nanomaterials are in can alter nanoproperties. Therefore, prior to nanotoxicity studies, we need to address how different solvents and temperatures can impact nanoparticle behavior. This study examines the effect of increased temperature and time on nanoparticle agglomeration. The nanoparticles used in this study were: SiO2 35nm, 51nm, 110nm, and 420nm,

Michael Moulton; Kyung Yu; Laura Braydich-Stolle; John Schlager; Amanda Schrand; Saber Hussain

2008-01-01

216

Crystal agglomeration of europium oxalate in reaction crystallization using double-jet semi-batch reactor  

SciTech Connect

The particle agglomeration of europium oxalate was investigated in a double-jet semi-batch reactor over a wide range of operating variables, including the agitation speed, reactant feed rate, and reactant concentration. The size of the agglomerates was directly dictated by the particle collision and supersaturation promoting agglomeration and the fluid shear force inhibiting agglomeration. Thus, with a longer feeding time and higher feed concentration for the reaction crystallization, the mean particle size increased, while the corresponding total particle population decreased due to the enhanced chance of particle agglomeration, resulting from a longer residence time and higher supersaturation in the reactor. Agitation was found to exhibit a rather complicated influence on particle agglomeration. Although both particle collision and turbulent fluid shear were promoted by an increase in the mixing intensity, the crystal agglomeration of europium oxalate was maximized at around 500 rpm of agitation speed due to an optimized balance between particle aggregation and breakage.

Kim, Woo-Sik; Kim, Woon-Soo; Kim, Kwang-Seok; Kim, Joon-Soo; Ward, Michael D

2004-02-02

217

Increased Oil Production and Reserves Utilizing Secondary/Tertiary Recovery Techniques on Small Reservoirs in the Paradox Basin, Utah.  

SciTech Connect

The primary objective of this project is to enhance domestic petroleum production by demonstration and technology transfer of an advanced oil recovery technology in the Paradox basin, southeastern Utah. If this project can demonstrate technical and economic feasibility, the technique can be applied to approximately 100 additional small fields in the Paradox basin alone, and result in increased recovery of 150 to 200 million barrels of oil. This project is designed to characterize five shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation and choose the best candidate for a pilot demonstration project for either a waterflood or carbon dioxide- (CO{sub 2}-) flood project. The field demonstration, monitoring of field performance, and associated validation activities will take place in the Paradox basin within the Navajo Nation. The results of this project will be transferred to industry and other researchers through a petroleum extension service, creation of digital databases for distribution, technical workshops and seminars, field trips, technical presentations at national and regional professional meetings, and publication in newsletters and various technical or trade journals.

Chidsey, T.C. Jr.; Lorenz, D.M.; Culham, W.E.

1997-10-15

218

Increased Oil Production and Reserves Utilizing Secondary/Tertiary Recovery Techniques on Small Reservoirs in the Paradox Basin, Utah  

SciTech Connect

The primary objective of this project is to enhance domestic petroleum production by demonstration and technology transfer of an advanced oil recovery technology in the Paradox basin, southeastern Utah. If this project can demonstrate technical and economic feasibility, the technique can be applied to about 100 additional small fields in the Paradox basin alone, and result in increased recovery of 150 to 200 million bbl of oil. This project is designed to characterize five shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation and choose the best candidate for a pilot demonstration project for either a waterflood or carbon dioxide-(CO-) flood 2 project. The field demonstration, monitoring of field performance, and associated validation activities will take place in the Paradox basin within the Navajo Nation. The results of this project will be transferred to industry and other researchers through a petroleum extension service, creation of digital databases for distribution, technical workshops and seminars, field trips, technical presentations at national and regional professional meetings, and publication in newsletters and various technical or trade journals.

Allison, M. Lee; Chidsey, Jr., Thomas

1999-11-03

219

Turbulent hydrodynamic stress induced dispersion and fragmentation of nanoscale agglomerates.  

PubMed

High pressure dispersion nozzles of 2.5-10 mm length and 125 microm diameter have been characterized in terms of fluid dynamics and dispersion experiments at 100-1400 bar. Elongational stresses at the nozzle entry (5 x 10(5) Pa) and turbulent stresses up to 10(5) Pa at a Reynolds number of 25,000 in turbulent channel flow are identified crucial for desagglomeration and aggregate fragmentation. Maximum stresses are calculated on representative particle tracks and related to agglomerate breakage. Agglomerates in the experimental study are in the range of the Kolmogorov micro scale (100-400 nm) and therefore break due to turbulent energy dissipation in viscous flow. Bond strength distributions could be determined experimentally from particle size distributions and fluid dynamics simulations, with primary particle erosion determined as dispersion mechanism for diffusion flame silica particles. Nanoscale agglomerates show a power law scaling for breakage with scaling exponents diverging from theory of floc dispersion. This is attributed to their strong bonding by sinter necks. PMID:17109876

Wengeler, R; Nirschl, H

2007-02-15

220

Nifedipine Nanoparticle Agglomeration as a Dry Powder Aerosol Formulation Strategy  

PubMed Central

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

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

2009-01-01

221

Recovering Bioactive Compounds from Olive Oil Filter Cake by Advanced Extraction Techniques  

PubMed Central

The potential of by-products generated during extra-virgin olive oil (EVOO) filtration as a natural source of phenolic compounds (with demonstrated bioactivity) has been evaluated using pressurized liquid extraction (PLE) and considering mixtures of two GRAS (generally recognized as safe) solvents (ethanol and water) at temperatures ranging from 40 to 175 °C. The extracts were characterized by high-performance liquid chromatography (HPLC) coupled to diode array detection (DAD) and electrospray time-of-flight mass spectrometry (HPLC-DAD-ESI-TOF/MS) to determine the phenolic-composition of the filter cake. The best isolation procedure to extract the phenolic fraction from the filter cake was accomplished using ethanol and water (50:50, v/v) at 120 °C. The main phenolic compounds identified in the samples were characterized as phenolic alcohols or derivatives (hydroxytyrosol and its oxidation product), secoiridoids (decarboxymethylated and hydroxylated forms of oleuropein and ligstroside aglycones), flavones (luteolin and apigenin) and elenolic acid derivatives. The PLE extraction process can be applied to produce enriched extracts with applications as bioactive food ingredients, as well as nutraceuticals. PMID:25226536

Lozano-Sanchez, Jesus; Castro-Puyana, Maria; Mendiola, Jose A.; Segura-Carretero, Antonio; Cifuentes, Alejandro; Ibanez, Elena

2014-01-01

222

Agglomeration processes sustained by dust density waves in Ar/C{sub 2}H{sub 2} plasma: From C{sub 2}H{sub 2} injection to the formation of an organized structure  

SciTech Connect

In this paper, an experimental investigation of dust particle agglomeration in a capacitively coupled RF discharge is reported. Carbonaceous particles are produced in an argon plasma using acetylene. As soon as the particle density becomes sufficient, dust density waves (DDWs) are spontaneously excited within the cathode sheath. Recently, it was proven that DDWs can significantly enhance the agglomeration rate between particles by transferring them a significant kinetic energy. Thus, it helps them to overcome Coulomb repulsion. The influence of this mechanism is studied from acetylene injection to the formation of very large agglomerates forming an organized structure after a few dozens of seconds. For this purpose, three diagnostic tools are used: extinction measurements to probe nanometer-sized particles, fast imaging for large agglomerates and a dust extraction technique developed for ex-situ analysis.

Dap, Simon; Hugon, Robert; Poucques, Ludovic de; Briancon, Jean-Luc; Bougdira, Jamal [Universite de Lorraine-Institut Jean Lamour, Dpt CP2S UMR 7198 CNRS, Faculte des Sciences et Technologies, BP 70239, 54506 Vandoeuvre-les-Nancy Cedex (France); Lacroix, David [Universite de Lorraine-LEMTA, UMR 7563 CNRS, Faculte des Sciences et Technologies, BP 70239, 54506 Vandoeuvre-les-Nancy Cedex (France)

2013-03-15

223

Evaluation of optical and electronic properties of silicon nano-agglomerates embedded in SRO: applying density functional theory  

NASA Astrophysics Data System (ADS)

In systems in atomic scale and nanoscale such as clusters or agglomerates constituted by particles from a few to less than 100 atoms, quantum confinement effects are very important. Their optical and electronic properties are often dependent on the size of the systems and the way in which the atoms in these clusters are bonded. Generally, these nanostructures display optical and electronic properties significantly different to those found in corresponding bulk materials. Silicon agglomerates embedded in silicon rich oxide (SRO) films have optical properties, which have been reported to be directly dependent on silicon nanocrystal size. Furthermore, the room temperature photoluminescence (PL) of SRO has repeatedly generated a huge interest due to its possible applications in optoelectronic devices. However, a plausible emission mechanism has not been widely accepted in the scientific community. In this work, we present a short review about the experimental results on silicon nanoclusters in SRO considering different techniques of growth. We focus mainly on their size, Raman spectra, and photoluminescence spectra. With this as background, we employed the density functional theory with a functional B3LYP and a basis set 6-31G* to calculate the optical and electronic properties of clusters of silicon (constituted by 15 to 20 silicon atoms). With the theoretical calculation of the structural and optical properties of silicon clusters, it is possible to evaluate the contribution of silicon agglomerates in the luminescent emission mechanism, experimentally found in thin SRO films.

Espinosa-Torres, Néstor D.; la Luz, David Hernández-de; Flores-Gracia, José Francisco J.; Luna-López, José A.; Martínez-Juárez, Javier; Vázquez-Valerdi, Diana E.

2014-09-01

224

Evaluation of optical and electronic properties of silicon nano-agglomerates embedded in SRO: applying density functional theory  

PubMed Central

In systems in atomic scale and nanoscale such as clusters or agglomerates constituted by particles from a few to less than 100 atoms, quantum confinement effects are very important. Their optical and electronic properties are often dependent on the size of the systems and the way in which the atoms in these clusters are bonded. Generally, these nanostructures display optical and electronic properties significantly different to those found in corresponding bulk materials. Silicon agglomerates embedded in silicon rich oxide (SRO) films have optical properties, which have been reported to be directly dependent on silicon nanocrystal size. Furthermore, the room temperature photoluminescence (PL) of SRO has repeatedly generated a huge interest due to its possible applications in optoelectronic devices. However, a plausible emission mechanism has not been widely accepted in the scientific community. In this work, we present a short review about the experimental results on silicon nanoclusters in SRO considering different techniques of growth. We focus mainly on their size, Raman spectra, and photoluminescence spectra. With this as background, we employed the density functional theory with a functional B3LYP and a basis set 6-31G* to calculate the optical and electronic properties of clusters of silicon (constituted by 15 to 20 silicon atoms). With the theoretical calculation of the structural and optical properties of silicon clusters, it is possible to evaluate the contribution of silicon agglomerates in the luminescent emission mechanism, experimentally found in thin SRO films.

2014-01-01

225

A Navier-Stokes equation solver using agglomerated multigrid featuring directional coarsening and line-implicit smoothing  

NASA Astrophysics Data System (ADS)

An explicit agglomeration multigrid method is presented for the Navier-Stokes equations with the Spalart-Allmaras turbulence model and applied to turbulent aerodynamic flows. The use of agglomeration provides an automated method for producing a sequence of coarse grids for use with multigrid. The solver employs a finite-volume formulation with a multistage relaxation scheme to produce steady-state solutions. Artificial dissipation is provided through a blend of an undivided Laplacian and biharmonic operator. Block-Jacobi preconditioning with matrix dissipation has been implemented. This solver is capable of using structured and unstructured grids, including mixed-element grids, with the primary focus being the use of unstructured grids. Competitive convergence rates approaching the theoretical limit of 0.75 for a second-order method are demonstrated for inviscid flow problems. Validation of inviscid and viscous results relative to two reference solvers and experimental results are presented. The main focus of this research is the improvement of convergence rates for turbulent flow problems. The performance of explicit multigrid methods applied to turbulent flow problems has typically been shown to be far slower than that for inviscid flow problems. Two techniques to improve the performance of explicit agglomeration multigrid for turbulent flow problems are presented. Directional-coarsening alters the agglomeration algorithm to directly alleviate numerical stiffness arising from grids containing high-aspect-ratio cells. Line-implicit smoothing alters the block-Jacobi preconditioner to introduce implicit terms along non-crossing lines constructed in the grid. Both methods are investigated separately and in combination to determine the best set of parameters and the limits of these methods. Substantial reductions in the cost of obtaining a solution are demonstrated for laminar and turbulent flow problems, with solutions converged over 10 orders of residual reduction being obtained in 25--33% of the time required for the base multigrid solver using isotropic coarsening.

Lassaline, Jason Vern

226

POROSITIES OF PROTOPLANETARY DUST AGGLOMERATES FROM COLLISION EXPERIMENTS  

SciTech Connect

The aggregation of dust through sticking collisions is the first step of planet formation. The basic physical properties of the evolving dust aggregates strongly depend on the porosity of the aggregates; e.g., mechanical strength, thermal conductivity, and the gas-grain coupling time. Also, the outcome of further collisions depends on the porosity of the colliding aggregates. In laboratory experiments we study the growth of large aggregates of {approx}3 mm to 3 cm through continuous impacts of small dust agglomerates of 100 {mu}m in size, consisting of {mu}m grains at different impact velocities. The experiments show that agglomerates grow by direct sticking as well as through gravitational reaccretion. The latter can be regarded as a suitable analog to the reaccretion of fragments by gas drag in protoplanetary disks. Experiments were carried out in the velocity range between 1.5 m s{sup -1} and 7 m s{sup -1}. With increasing impact velocities the volume filling factor of the resulting agglomerates increases from {phi} = 0.2 for 1.5 m s{sup -1} to {phi} = 0.32 for 7 m s{sup -1}. These values are independent of the target size. Extrapolation of the measured velocity dependence of the volume filling factor implies that higher collision velocities will not lead to more compact aggregates. Therefore, {phi} = 0.32 marks a degree of compaction suitable for describing structures forming at v > 6 m s{sup -1}. At small collision velocities below 1 m s{sup -1}, highly porous structures with {phi} Almost-Equal-To 0.10 will form. For intermediate collision velocities porosities vary. Depending on the disk model and resulting relative velocities, objects in protoplanetary disks up to decimeters in size might evolve from highly porous ({phi} Almost-Equal-To 0.10) to compact ({phi} = 0.32) with a more complex intermediate size range of varying porosity.

Teiser, J.; Engelhardt, I.; Wurm, G., E-mail: jens.teiser@uni-due.de [Faculty of Physics, University Duisburg-Essen, Duisburg (Germany)

2011-11-20

227

Sensitivity Analysis and Experimental Investigation of Microstrip Resonator Technique for the in-process Moisture\\/Permittivity Measurement of Petrochemicals and Emulsions of Crude Oil and Water  

Microsoft Academic Search

An accurate, instantaneous, non-destructive, microstrip resonator technique has been applied to the measurement of permittivity and moisture in emulsions of crude oil and water. A single parameter, the resonant frequency of the microstrip resonator, is necessary for measurement of the real part of permittivity of the material. This is an advantage for on-line measurement. Assisted by dedicated software, the measurements

K. K. Joshi; R. D. Pollard

2006-01-01

228

Productivity and quality of volatile oil extracted from Mentha spicata and M. arvensis var. piperascens grown by a hydroponic system using the deep flow technique  

Microsoft Academic Search

The purpose of this study was to determine the differences between spearmint (Mentha spicata L.) and Japanese mint (M. arvensis L. var. piperascens Malinv.) cultivated in either soil or nutrient solution using the deep flow technique (DFT). The differences were measured\\u000a in terms of harvest period (full bloom period) and quantity and chemical components of volatile oils. The spearmint and

Sornkanok Vimolmangkang; Worapan Sitthithaworn; Danai Vannavanich; Sunisa Keattikunpairoj; Chuda Chittasupho

2010-01-01

229

Compaction of fine powders: from fluidized agglomerates to primary particles  

Microsoft Academic Search

In previous works it has been shown that fine powders (particle size 7 ?m \\u000a$$\\\\lesssim d_{p}$ $\\\\lesssim 20 \\\\mu$$m) exhibit two well differentiated behaviors in the compaction regime at low consolidation stresses ?\\u000a c\\u000a . At very low stresses\\u000a$$(\\\\sigma_{c} \\\\lesssim10 Pa)$$ the compaction process is governed by a critical-like dynamics of fractal agglomerates previously formed in the fluid-like regime, undergoing

Jose Manuel Valverde; Antonio Castellanos

2007-01-01

230

9286 Stars: An Agglomeration of Stellar Polarization Catalogs  

E-print Network

This is a revision. The revisions are minor. The new version of the catalog should be used in preference to the old. The most serious error in the older version was that $\\theta_diff$ was incorrect, being sometimes far too large, for Reiz and Franco entries; the correct values are all zero for that reference. We present an agglomeration of stellar polarization catalogs with results for 9286 stars. We have endeavored to eliminate errors, provide accurate (arcsecond) positions, sensibly weight multiple observations of the same star, and provide reasonable distances. This catalog is included as an ASCII file (catalog.txt) in the source of this submission.

Carl Heiles

1999-10-16

231

Agglomeration economies and location choice of Korean manufacturers within the United States  

Microsoft Academic Search

Employing the micro data for 1997–2004, we investigate the location decision of Korean-affiliated manufacturing investments in the United States. The conditional logit estimates confirm that although industry-specific Korean agglomeration and domestic agglomeration play an important role, the Foreign Direct Investment (FDI) location is more sensitively affected by the interstate difference in endowment conditions than by the same nationality agglomeration. Both

Ki-Dong Lee; Seok-Joon Hwang; Min-hwan Lee

2012-01-01

232

Agglomeration economies and location choice of Korean manufacturers within the United States  

Microsoft Academic Search

Employing the micro data for 1997–2004, we investigate the location decision of Korean-affiliated manufacturing investments in the United States. The conditional logit estimates confirm that although industry-specific Korean agglomeration and domestic agglomeration play an important role, the Foreign Direct Investment (FDI) location is more sensitively affected by the interstate difference in endowment conditions than by the same nationality agglomeration. Both

Ki-Dong Lee; Seok-Joon Hwang; Min-hwan Lee

2011-01-01

233

Agglomeration Economies among High Technology Firms in Advanced Production Areas: The Case of Denver\\/Boulder  

Microsoft Academic Search

LYONS D. (1995) Agglomeration economies among high technology firms in advanced production areas: the case of Denver\\/Boulder, Reg. Studies29, 265–278. Research on the agglomeration economies generated by high technology industry has tended to focus on either core high technology areas or fabrication clusters. This paper directs attention to intermediate or advanced production areas through an investigation of the agglomeration advantages

Donald Lyons

1995-01-01

234

Effects of operating conditions on agglomeration and habit of paracetamol crystals in anti-solvent crystallization  

Microsoft Academic Search

Effects of agitation speed and feeding rate on agglomeration and habit of paracetamol crystals in anti-solvent crystallization from water–acetone mixture are reported. Water is used as anti-solvent and is added in a semi-batch manner to a baffled 1-l crystallizer equipped with a marine-type impeller. A simple new method to characterize agglomeration degree has been proposed. Results show that agglomeration degree

Z. Q. Yu; R. B. H. Tan; P. S. Chow

2005-01-01

235

Effects of operating conditions on agglomeration and habit of paracetamol crystals in anti-solvent crystallization  

Microsoft Academic Search

Effects of agitation speed and feeding rate on agglomeration and habit of paracetamol crystals in anti-solvent crystallization from water acetone mixture are reported. Water is used as anti-solvent and is added in a semi-batch manner to a baffled 1-l crystallizer equipped with a marine-type impeller. A simple new method to characterize agglomeration degree has been proposed. Results show that agglomeration

Z. Q. Yu; R. B. H. Tan; P. S. Chow

2005-01-01

236

Melt agglomeration with polyethylene glycol beads at a low impeller speed in a high shear mixer.  

PubMed

This study was performed in order to evaluate the possibility of obtaining spherical agglomerates with a high content of meltable binder by a melt agglomeration process in a high shear mixer. Lactose monohydrate was melt agglomerated with polyethylene glycol (PEG) 1500 or 6000 in a 10-l high shear mixer at an impeller speed of 400 rpm. The PEG 1500 was used as a size fraction of beads, and the PEG 6000 as a fine powder, a powder, unfractionated beads, and size fractions of beads. It was found to be possible to incorporate a high amount of PEG (28% m/m of the amount of lactose), because the rather low impeller speed applied in the present experiments caused less densification of the agglomerates. The fine powder of the PEG 6000 caused a complete adhesion of the mass to the bowl shortly after melting. A rapid agglomerate growth by coalescence was found to be the dominant growth mechanism when agglomeration was performed with the PEG 6000 powder. The PEG beads resulted in a slow and more controllable agglomerate growth, because the growth occurred primarily by an immersion of the lactose particles in the surface of the molten binder droplets. The initial shape of the agglomerates produced with the PEG beads was similar to the spherical shape of the beads. This shape could not be maintained during the process due to a breakage of the agglomerates caused by a hollow structure of the PEG beads. PMID:11677074

Seo, A; Schaefer, T

2001-11-01

237

Transport, mixing and agglomeration of particles in turbulent flows  

NASA Astrophysics Data System (ADS)

This paper describes methods and approaches that have been used to simulate and model the transport, mixing and agglomeration of small particles in a flowing turbulent gas. The transported particles because of their inertia are assumed not to follow the motion of the large scales of the turbulence and or the motion of the small dissipating scales of the turbulence. We show how both these behaviours can be represented by a PDF approach analogous to that used in Classical Kinetic Theory. For large scale dispersion the focus is on transport in simple generic flows like statistically stationary homogeneous and isotropic turbulence and simple shear flows. Special consideration is given to the transport and deposition of particles in turbulent boundary layers. For small scale transport the focus is on how the the small scales of turbulence together with the particle inertial response enhances collision processes like particle agglomeration. In this case the importance of segregation and the formation of caustics, singularities and random uncorrelated motion is highlighted and discussed.

Reeks, Michael W.

2014-08-01

238

Synthesis and agglomeration of gold nanoparticles in reverse micelles  

NASA Astrophysics Data System (ADS)

Reverse micelles prepared in the system water, sodium bis-(2-ethylhexyl) sulfoccinate (AOT), and isooctane were investigated as a templating system for the production of gold nanoparticles from Au(III) and the reducing agent sulfite. A core-shell Mie model was used to describe the optical properties of gold nanoparticles in the reverse micelles. Dynamic light scattering of gold colloids in aqueous media and in reverse micelle solution indicated agglomeration of micelles containing particles. This was verified theoretically with an analysis of the total interaction energy between pairs of particles as a function of particle size. The analysis indicated that particles larger than about 8 nm in diameter should reversibly flocculate. Transmission electron microscopy measurements of gold nanoparticles produced in our reverse micelles showed diameters of 8-10 nm. Evidence of cluster formation was also observed. Time-correlated UV-vis absorption measurements showed a red shift for the peak wavelength. This was interpreted as the result of multiple scattering and plasmon interaction between particles due to agglomeration of micelles with particles larger than 8 nm.

Herrera, Adriana P.; Resto, Oscar; Briano, Julio G.; Rinaldi, Carlos

2005-07-01

239

Synthesis and agglomeration of gold nanoparticles in reverse micelles.  

PubMed

Reverse micelles prepared in the system water, sodium bis-(2-ethylhexyl) sulfoccinate (AOT), and isooctane were investigated as a templating system for the production of gold nanoparticles from Au(III) and the reducing agent sulfite. A core-shell Mie model was used to describe the optical properties of gold nanoparticles in the reverse micelles. Dynamic light scattering of gold colloids in aqueous media and in reverse micelle solution indicated agglomeration of micelles containing particles. This was verified theoretically with an analysis of the total interaction energy between pairs of particles as a function of particle size. The analysis indicated that particles larger than about 8 nm in diameter should reversibly flocculate. Transmission electron microscopy measurements of gold nanoparticles produced in our reverse micelles showed diameters of 8-10 nm. Evidence of cluster formation was also observed. Time-correlated UV-vis absorption measurements showed a red shift for the peak wavelength. This was interpreted as the result of multiple scattering and plasmon interaction between particles due to agglomeration of micelles with particles larger than 8 nm. PMID:21727484

Herrera, Adriana P; Resto, Oscar; Briano, Julio G; Rinaldi, Carlos

2005-07-01

240

Modeling agglomeration processes in fluid-bed granulation  

SciTech Connect

Many agrochemicals are formulated as water dispersive granules through agglomeration, beginning with a fine powder ({approximately}1 {micro}m) and ending with granules on the order of 500 {micro}m. Powders are charged into a granulation system with a liquid binding agent, and granules are subsequently grown to an appropriate size. Granulation in fluid beds is presented using a mass conserving discretized population balance equation. Coalesce kernels governing the rate and extent of granulation are assumed dependent on the Stokes number, which is indirectly liked to important process variables (air and under flow rate, bed charge, bed geometry) such that the physical processes governing particle coalescence and rebound are correlated to process variables. A new coalescence kernel is proposed based on physical insight, simplicity, and deterministic equivalent modeling to account for uncertainty. This kernel is based on a Stokes number method where uncertainty in the Stokes number is characterized by polynomial chaos expansions. The magnitude of the coalescence kernel is proportional to the probability of the distribution of Stokes number exceeding a critical value. This mechanistic/semiempirical approach to fluid-bed agglomeration fosters an environment for process scaleup by eliminating specific equipment and process variable constraints to focus on the underlying mechanisms for proper scale-up procedures. Model predictions using this new kernel are then compared to experimental pilot-plant observations.

Cryer, S.A.

1999-10-01

241

Extraction of oil slicks on the sea surface from optical satellite images by using an anomaly detection technique  

NASA Astrophysics Data System (ADS)

Many methods for the detection of oil pollution on the sea surface from remotely sensed images have been developed in recent years. However, because of the diverse physical properties of oil on the sea surface in the visible wavelengths, such images are easily affected by the surrounding environment. This is a common difficulty encountered when optical satellite images are used as data sources for observing oil slicks on the sea surface. However, provided the spectral interference generated by the surrounding environment can be regarded as noise and properly modeled, the spectral anomalies caused by an oil slick on normal sea water may be observed after the suppression of this noise. In this study, sea surface oil slicks are extracted by detecting spectral anomalies in multispectral optical satellite images. First, assuming that the sea water and oil slick comprise the dominant background and target anomaly, respectively, an RX algorithm is used to enhance the oil slick anomaly. The oil slick can be distinguished from the sea water background after modeling and suppression of inherent noise. Next, a Gaussian mixture model is used to characterize the statistical distributions of the background and anomaly, respectively. The expectation maximization (EM) algorithm is used to obtain the parameters needed for the Gaussian mixture model. Finally, according to the Bayesian decision rule of minimum error, an optimized threshold can be obtained to extract the oil slick areas from the source image. Furthermore, with the obtained Gaussian distributions and optimized threshold, a theoretical false alarm level can be established to evaluate the quality of the extracted oil slicks. Experimental results show that the proposed method can not only successfully detect oil slicks from multispectral optical satellite images, but also provide a quantitative accuracy evaluation of the detected image.

Chen, Chi-Farn; Chang, Li-Yu

2010-12-01

242

The role of nitrogen and sulphur bearing compounds in the wettability of oil reservoir rocks: an approach with nuclear microanalysis and other related surface techniques  

NASA Astrophysics Data System (ADS)

Oil recovery is strongly influenced by the wettability of the reservoir rock. Some constituents of the crude oil (polar compounds and heavy fractions such as asphaltenes with heteroatoms) are believed to react with the reservoir rock and to condition the local wettability. Therefore, it is important to obtain as much knowledge as possible about the characteristics of the organic matter/mineral interactions. This study is devoted to the description at the microscopic scale of the distribution of some heavy fractions of crude oil (asphaltenes) and nitrogen molecules (pyridine and pyrrole) on model minerals of sandstone reservoir rocks such as silica and clays. Nuclear microanalysis, X-Ray Photoelectron Spectroscopy and other related microscopic imaging techniques allow to study the distribution and thickness of the organic films. The respective influences of the nature of the mineral substrate and the organic matter are studied. The important role played by the nitrogen compounds in the adsorption of organic matter is emphasized.

Mercier, F.; Toulhoat, N.; Potocek, V.; Trocellier, P.

1999-04-01

243

A 3D agglomeration multigrid solver for the Reynolds-averaged Navier-Stokes equations on unstructured meshes  

NASA Technical Reports Server (NTRS)

An agglomeration multigrid strategy is developed and implemented for the solution of three-dimensional steady viscous flows. The method enables convergence acceleration with minimal additional memory overheads, and is completely automated, in that it can deal with grids of arbitrary construction. The multigrid technique is validated by comparing the delivered convergence rates with those obtained by a previously developed overset-mesh multigrid approach, and by demonstrating grid independent convergence rates for aerodynamic problems on very large grids. Prospects for further increases in multigrid efficiency for high-Reynolds number viscous flows on highly stretched meshes are discussed.

Marvriplis, D. J.; Venkatakrishnan, V.

1995-01-01

244

Extraction of oil slicks on the sea surface from optical satellite images by using an anomaly detection technique  

Microsoft Academic Search

Many methods for the detection of oil pollution on the sea surface from remotely sensed images have been developed in recent years. However, because of the diverse physical properties of oil on the sea surface in the visible wavelengths, such images are easily affected by the surrounding environment. This is a common difficulty encountered when optical satellite images are used

Chi-Farn Chen; Li-Yu Chang

2010-01-01

245

Flow cytometry: A promising technique for the study of silicone oil-induced particulate formation in protein formulations  

Microsoft Academic Search

Subvisible particles in formulations intended for parenteral administration are of concern in the biopharmaceutical industry. However, monitoring and control of subvisible particulates can be complicated by formulation components, such as the silicone oil used for the lubrication of prefilled syringes, and it is difficult to differentiate microdroplets of silicone oil from particles formed by aggregated protein. In this study, we

D. Brett Ludwig; Joseph T. Trotter; John P. Gabrielson; John F. Carpenter; Theodore W. Randolph

2011-01-01

246

Productivity and quality of volatile oil extracted from Mentha spicata and M. arvensis var. piperascens grown by a hydroponic system using the deep flow technique.  

PubMed

The purpose of this study was to determine the differences between spearmint (Mentha spicata L.) and Japanese mint (M. arvensis L. var. piperascens Malinv.) cultivated in either soil or nutrient solution using the deep flow technique (DFT). The differences were measured in terms of harvest period (full bloom period) and quantity and chemical components of volatile oils. The spearmint and Japanese mint were cultivated in four different nutrient formulas: plant standard nutrient, plant standard nutrient with an amino acid mixture, plant standard nutrient with a sulphur compound, and a combination of plant standard nutrient with an amino acid mixture and a sulphur compound. We observed that cultivation of spearmint and Japanese mint in nutrient solution using DFT is an effective method to provide high production of volatile oil, since it results in an earlier harvest period and higher quantity of volatile oil. We determined that for spearmint an amino acid mixture is an appropriate nutrient supplement to enhance production of volatile oil with optimum carvone content. Finally, we observed high menthol content in Japanese mint grown in all four nutrient formulas; however, supplementation with a combination of sulphur fertilisation and amino acid mixture yields the highest quantity of volatile oil. PMID:19763744

Vimolmangkang, Sornkanok; Sitthithaworn, Worapan; Vannavanich, Danai; Keattikunpairoj, Sunisa; Chittasupho, Chuda

2010-01-01

247

DEFORESTATION, GROWTH AND AGGLOMERATION EFFECTS: EVIDENCE FROM AGRICULTURE IN THE BRAZILIAN AMAZON  

Microsoft Academic Search

The role of population growth and migration has been emphasized as a key variable to explain deforestation and land conversion in developing countries. The spatial distribution of human population and economic activities is remarkably uneven. At any geographical scale we find that different forms of agglomerations are pervasive. On the one hand, in central countries or regions, agglomeration is reflected

Danilo Camargo Igliori

2006-01-01

248

Do Public Transport Improvements Increase Agglomeration Economies? A Review of Literature and an Agenda for Research  

Microsoft Academic Search

Public transport improvements may increase economic productivity if they enable the growth and densification of cities, downtowns, or industrial clusters and thereby increase external agglomeration economies. It has been argued that the potential agglomeration benefits are large; if so, understanding them better would be useful in making funding decisions about public transport improvements. We reviewed theoretical and empirical literature on

Daniel G. Chatman; Robert B. Noland

2011-01-01

249

On temperature- and space-dimension dependent matter agglomerations in a mature growing stage  

Microsoft Academic Search

Model matter agglomerations, with temperature as leading control parameter, have been considered, and some of their characteristics have been studied. The primary interest has been focused on the grain volume fluctuations, the magnitude of which readily differentiates between two commonly encountered types of matter agglomeration\\/aggregation processes, observed roughly for high- and low-density matter organizations. The two distinguished types of matter

A. Gadomski; J. M. Rub ´ i; J. ?uczka; M. Ausloos

2005-01-01

250

Technical Change and Productive Inefficiency Change in Norwegian Salmon Farming: The Influence of Regional Agglomeration Externalities  

Microsoft Academic Search

This paper analyses the factors explaining productivity and efficiency differences across salmon aquaculture farms, with an emphasis on agglomeration externalities. We specify a stochastic frontier production model with agglomeration indexes included in both the frontier production function and the technical inefficiency model. The frontier model is estimated on a rich panel data set with 2,738 observations on 577 farms. Our

Ragnar Tveterås; George E. Battese

251

Preventing agglomeration and growth of ice particles in water with suitable additives  

Microsoft Academic Search

The present paper reviews the technologies on preventing the agglomeration and the growth of ice particles in water with a very small amount of suitable additives. This summarizes studies on the effects of anti-agglomeration of ice particles and suppression of ice growth by using anti-freeze protein and its substitutes or some kinds of surfactants, and on their applications to ice

Hideo Inaba; Takaaki Inada; Akihiko Horibe; Hiroshi Suzuki; Hiromoto Usui

2005-01-01

252

Crystal agglomeration is a major element in calcium oxalate urinary stone formation  

Microsoft Academic Search

Crystal agglomeration is a major element in calcium oxalate urinary stone formation. The effects of urines from 36 healthy subjects and 86 calcium oxalate renal stone formers on calcium oxalate monohydrate crystallization kinetics were studied using a seeded crystal growth method in which the solubility, the growth and the agglomeration of the crystals are measured as three separate and system-independent

Dik J Kok; Socrates E Papapoulos; Olav L M Bijvoet

1990-01-01

253

The Effect of Padding Foam on the Compression Characteristics of Some Agglomerated Food Powders  

Microsoft Academic Search

Selected padding foam was used to reduce attrition in agglomerated food powders. This is a widely used strategy in fruits and vegetables during harvesting and processing to minimize impact damage. The objective of this research was to determine the padding effect on some agglomerated food powders when plastic foams of different thicknesses were added in the powder bed at different

H. Yan; G. V. Barbosa-Cánovas

2001-01-01

254

AN ISOTHERMAL MODEL OF AGGLOMERATION IN A FLASH SMELTING REACTION SHAFT  

Microsoft Academic Search

A steady-state, isothermal model of agglomeration in turbulent, gas-particle flow through a flash smelting reaction shaft is developed. Collisions between pairs of particles are simulated using the turbulent shear kernel of Saffman and Turner (1956). The influence of inlet velocity and turbulence intensity from the burner on collisions and subsequent agglomeration were considered. Increasing the inlet velocity and particle residence

David R. HIGGINS; Malcolm R. DAVIDSON

255

Dynamic modeling of a batch crystallization process: A stochastic approach for agglomeration and attrition process  

Microsoft Academic Search

This paper deals with the dynamic modeling of a batch crystallizer. A complete model taking into account primary and secondary nucleations, crystal growth, agglomeration and attrition mechanisms is established. The proposed model is not restricted to binary agglomeration and breakage phenomena. From markovian considerations, continuous kernel functions are built and the basic balance equations are then presented. The complete model

N. Laloue; F. Couenne; Y. Le Gorrec; M. Kohl; D. Tanguy; M. Tayakout-Fayolle

2007-01-01

256

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...

257

Bed material agglomeration during fluidized bed combustion. Technical progress report, January 1, 1993March 31, 1993  

Microsoft Academic Search

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 and to relate these reactions to specific causes. A survey of agglomeration and deposit formation in industrial fluidized bed boilers is in progress. Preliminary results indicate that at least five boilers were experiencing some

R. C. Brown; M. R. Dawson; S. D. Noble

1993-01-01

258

Identification of micro parameters for discrete element simulation of agglomerates  

NASA Astrophysics Data System (ADS)

The mechanical behaviour of solid particles like agglomerates, granules or crystals strongly depends on their micro structure, e.g. structural defects and porosity. In order to model the mechanical behaviour of these inhomogeneous media the discrete element method has been proven to be an appropriate tool. The model parameters used are typically micro parameters like bond stiffness, particle-particle contact stiffness, strength of the bonds. Due to the lack of general methods for a direct micro parameter determination, normally laborious parameter adaptation has to be done in order to fit experiment and simulation. In this contribution a systematic and automatic way for parameter adaptation using real experiments is proposed. Due to the fact, that discrete element models are typically systems of differential equations of very high order, gradient based methods are not suitable. Hence, the focus will be on derivative free methods.

Palis, Stefan; Antonyuk, Sergiy; Dosta, Maksym; Heinrich, Stefan

2013-06-01

259

Dynamic Breakage of Agglomerates under Normal Impact and Tangential Friction  

NASA Astrophysics Data System (ADS)

Numerical simulations with Discrete Element Method are used to study agglomerate breakage under two different kinds of dynamic solicitations: normal impact and tangential friction. Simple mechanistic models based on energy balance are developed for each case, and show good agreement with the results of the simulations. As far as impact is concerned, damage ratio, defined as the ratio of the number of broken bonds to the initial number of bonds, is found to depend on a dimensionless number I = kv2/c2, where v is the impacting velocity, and k and c are microscopic parameters describing material stiffness and cohesiveness. In the case of tangential friction, damage ratio is shown to depend on J = kv/c2. This model appears to be consistent with some available experimental data on impact and abrasion wear tests.

Le Bouteiller, Caroline; Naaïm, Mohamed

2009-06-01

260

Gravitational agglomeration of post-HCDA LMFBR aerosols: nonspherical particles  

SciTech Connect

Aerosol behavior analysis computer programs have shown that temporal aerosol size distributions in nuclear reactor containments are sensitive to shape factors. This research investigates shape factors by a detailed theoretical analysis of hydrodynamic interactions between a nonspherical particle and a spherical particle undergoing gravitational collisions in an LMFBR environment. First, basic definitions and expressions for settling speeds and collisional efficiencies of nonspherical particles are developed. These are then related to corresponding quantities for spherical particles through shape factors. Using volume equivalent diameter as the defining length in the gravitational collision kernel, the aerodynamic shape factor, the density correction factor, and the gravitational collision shape factor, are introduced to describe the collision kernel for collisions between aerosol agglomerates. The Navier-Stokes equation in oblate spheroidal coordinates is solved to model a nonspherical particle and then the dynamic equations for two particle motions are developed. A computer program (NGCEFF) is constructed, and the dynamical equations are solved by Gear's method.

Tuttle, R.F.; Loyalka, S.K.

1982-12-01

261

In Situ Formation and Evolution of Gas Hydrates in Water-in-Oil Emulsions Using Pressure Rheometry  

NASA Astrophysics Data System (ADS)

In oil and gas production and transportation a major concern is the formation of gas hydrates (crystalline gas-water inclusion compounds that are stable at high pressures and low temperatures). Gas hydrates have a tenacious ability to plug pipelines, and may lead to unscheduled shut downs. The successful operation of pipeline transport with gas hydrates particles will depend on the ability to control gas hydrate agglomerations and depositions. Gas hydrates can be thermodynamically inhibited but this is proving cost ineffective and environmentally unfriendly. For this reason the oil/gas industry is moving to hydrate management rather than traditional methods of thermodynamic inhibition. One intriguing possibility would be to convert the water in the pipelines to non-agglomerating gas hydrates and then flow the slurry. However, this cannot be reliably achieved until basic understanding of hydrate slurry rheology is gained. To develop this fundamental understanding, in situ pressurized gas hydrate formation and rheological measurements from a water-in-oil emulsion have been conducted. In this work, small amplitude oscillatory and steady shear techniques have been used to characterize the rheological properties of these systems. The results demonstrate that hydrate formation can be detected in steady shear and oscillatory measurements, where a large viscosity (and elastic modulus) increase coincides with hydrate formation. Since temperature and pressure affect the thermodynamic stability of hydrates these are particular key variables that need to be tuned for this system.

Rensing, P. J.; Liberatore, M. W.; Tonmukayakul, N.; Koh, C. A.; Sloan, E. D.

2008-07-01

262

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

NASA Astrophysics Data System (ADS)

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.

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

2013-03-01

263

Influence of primary-particle density in the morphology of agglomerates  

NASA Astrophysics Data System (ADS)

Agglomeration processes occur in many different realms of science, such as colloid and aerosol formation or formation of bacterial colonies. We study the influence of primary-particle density in agglomerate structures using diffusion-controlled Monte Carlo simulations with realistic space scales through different regimes (diffusion-limited aggregation and diffusion-limited colloid aggregation). The equivalence of Monte Carlo time steps to real time scales is given by Hirsch's hydrodynamical theory of Brownian motion. Agglomerate behavior at different time stages of the simulations suggests that three indices (the fractal exponent, the coordination number, and the eccentricity index) characterize agglomerate geometry. Using these indices, we have found that the initial density of primary particles greatly influences the final structure of the agglomerate, as observed in recent experimental works.

Camejo, M. D.; Espeso, D. R.; Bonilla, L. L.

2014-07-01

264

Investigations on a novel inductive concept frequency technique for the grading of oil palm fresh fruit bunches.  

PubMed

From the Malaysian harvester's perspective, the determination of the ripeness of the oil palm (FFB) is a critical factor to maximize palm oil production. A preliminary study of a novel oil palm fruit sensor to detect the maturity of oil palm fruit bunches is presented. To optimize the functionality of the sensor, the frequency characteristics of air coils of various diameters are investigated to determine their inductance and resonant characteristics. Sixteen samples from two categories, namely ripe oil palm fruitlets and unripe oil palm fruitlets, are tested from 100 Hz up to 100 MHz frequency. The results showed the inductance and resonant characteristics of the air coil sensors display significant changes among the samples of each category. The investigations on the frequency characteristics of the sensor air coils are studied to observe the effect of variations in the coil diameter. The effect of coil diameter yields a significant 0.02643 MHz difference between unripe samples to air and 0.01084 MHz for ripe samples to air. The designed sensor exhibits significant potential in determining the maturity of oil palm fruits. PMID:23435051

Harun, Noor Hasmiza; Misron, Norhisam; Sidek, Roslina Mohd; Aris, Ishak; Ahmad, Desa; Wakiwaka, Hiroyuki; Tashiro, Kunihisa

2013-01-01

265

Investigations on a Novel Inductive Concept Frequency Technique for the Grading of Oil Palm Fresh Fruit Bunches  

PubMed Central

From the Malaysian harvester's perspective, the determination of the ripeness of the oil palm (FFB) is a critical factor to maximize palm oil production. A preliminary study of a novel oil palm fruit sensor to detect the maturity of oil palm fruit bunches is presented. To optimize the functionality of the sensor, the frequency characteristics of air coils of various diameters are investigated to determine their inductance and resonant characteristics. Sixteen samples from two categories, namely ripe oil palm fruitlets and unripe oil palm fruitlets, are tested from 100 Hz up to 100 MHz frequency. The results showed the inductance and resonant characteristics of the air coil sensors display significant changes among the samples of each category. The investigations on the frequency characteristics of the sensor air coils are studied to observe the effect of variations in the coil diameter. The effect of coil diameter yields a significant 0.02643 MHz difference between unripe samples to air and 0.01084 MHz for ripe samples to air. The designed sensor exhibits significant potential in determining the maturity of oil palm fruits. PMID:23435051

Harun, Noor Hasmiza; Misron, Norhisam; Sidek, Roslina Mohd; Aris, Ishak; Ahmad, Desa; Wakiwaka, Hiroyuki; Tashiro, Kunihisa

2013-01-01

266

SIMPLE TECHNIQUES FOR ASSESSING IMPACTS OF OIL AND GAS OPERATIONS ON PUBLIC LANDS- USE OF A PHOTOIONIZATION DETECTOR TO EVALUATE HYDROCARBONS IN THE SUBSURFACE  

Microsoft Academic Search

Simple, cost-effective techniques are needed for land managers to assess the environmental impacts of oil and gas production activities on public lands, so that sites may be prioritized for remediation or for further, more formal assessment. Field-portable instruments provide real-time data and allow the field investigator to extend an assessment beyond simply locating and mapping obvious impacts. Field investigators can

James K. Otton; Robert A. Zielinski

267

Ligand-dominated temperature dependence of agglomeration kinetics and morphology in alkyl-thiol-coated gold nanoparticles  

NASA Astrophysics Data System (ADS)

The stability of nanoparticle suspensions and the details of their agglomeration depend on the interactions between particles. We study this relationship in gold nanoparticles stabilized with different alkyl thiols in heptane. Temperature-dependent interactions were inferred from small-angle x-ray scattering, agglomeration kinetics from dynamic light scattering, and agglomerate morphologies from transmission electron microscopy. We find that the particles precipitate at temperatures below the melting temperatures of the dry ligands. Agglomerates grow with rates that depend on the temperature: Around precipitation temperature, globular agglomerates form slowly, while at lower temperatures, fibrilar agglomerates form rapidly. All agglomerates contain random dense packings rather than crystalline superlattices. We conclude that ligand-ligand and ligand-solvent interactions of the individual particles dominate suspension stability and agglomeration kinetics. The microscopic packing is dominated by interactions between the ligands of different nanoparticles.

Born, Philip; Kraus, Tobias

2013-06-01

268

A numerical\\/empirical technique for history matching and predicting cyclic steam performance in Canadian oil sands reservoirs  

Microsoft Academic Search

The oil sands of Alberta contain some one trillion barrels of bitumen-in-place, most contained in the McMurray, Wabiskaw, Clearwater, and Grand Rapids formations. Depth of burial is 0--550 m, 10% of which is surface mineable, the rest recoverable by in-situ technology-driven enhanced oil recovery schemes. To date, significant commercial recovery has been attributed to Cyclic Steam Stimulation (CSS) using vertical

Theodore Henry Leshchyshyn

1999-01-01

269

Prediction technique for transformer oil breakdown voltage via multi-parameter correlation based on grey theory and BP neural network  

Microsoft Academic Search

Prediction of breakdown voltage of transformer oil has a great significance to the fault diagnosis and daily maintenance of transformer. Based on the correlation of performance parameters of transformer oil and the prominent fault-tolerance, non-linear approximation, and self-learning capabilities of BP neural network, this paper constructed a prediction method of breakdown voltage via multi-parameter correlation under the development environment of

Zhi Li; Jia-yuan Hu; Shun-an Cao; Jian-li Xie

2010-01-01

270

Influence of decomposition parameters on agglomeration process and total soda content in precipitated Al(OH) 3  

Microsoft Academic Search

Grain size composition of precipitated Al(OH)3 is dependent on the mechanism of decomposition process of the caustic solution which determines crystal growth process, agglomeration process and secondary nucleation. Because the literature data shows that the growth rate is very low, the agglomeration process plays an important role in increasing the initial particle size. On the other hand, the agglomeration process

I. Blagojevi?; D. Ble?i?; R. Vasiljevi?

1999-01-01

271

Pipeline Agglomerator Design Problem: Applications of Population Balances R. B. Diemer, Jr. and S. H. Ehrman, 2003  

E-print Network

agglomeration via the sum of the continuum Brownian and Saffman- Turner turbulent kernels: ( ) ( ) 1/3 1/3 2/3 1Pipeline Agglomerator Design Problem: Applications of Population Balances © R. B. Diemer, Jr. and S successfully quenched by cooling the gas without forming heavily sintered agglomerates. You now need to collect

Ehrman, Sheryl H.

272

Nanosized rods agglomerates as a new approach for formulation of a dry powder inhaler  

PubMed Central

Background: Nanosized dry powder inhalers provide higher stability for poorly water-soluble drugs as compared with liquid formulations. However, the respirable particles must have a diameter of 1–5 ?m in order to deposit in the lungs. Controlled agglomeration of the nanoparticles increases their geometric particle size so they can deposit easily in the lungs. In the lungs, they fall apart to reform nanoparticles, thus enhancing the dissolution rate of the drugs. Theophylline is a bronchodilator with poor solubility in water. Methods: Nanosized theophylline colloids were formed using an amphiphilic surfactant and destabilized using dilute sodium chloride solutions to form the agglomerates. Results: The theophylline nanoparticles thus obtained had an average particle size of 290 nm and a zeta potential of ?39.5 mV, whereas the agglomerates were 2.47 ?m in size with a zeta potential of ?28.9 mV. The release profile was found to follow first-order kinetics (r2 > 0.96). The aerodynamic characteristics of the agglomerated nanoparticles were determined using a cascade impactor. The behavior of the agglomerate was significantly better than unprocessed raw theophylline powder. In addition, the nanoparticles and agglomerates resulted in a significant improvement in the dissolution of theophylline. Conclusion: The results obtained lend support to the hypothesis that controlled agglomeration strategies provide an efficient approach for the delivery of poorly water-soluble drugs into the lungs. PMID:21383856

Salem, HF; Abdelrahim, ME; Eid, K Abo; Sharaf, MA

2011-01-01

273

Impact milling of pharmaceutical agglomerates in the wet and dry states.  

PubMed

This study focused on the milling of wet granulated agglomerates at points before and after drying in a typical high-shear pharmaceutical process train. These steps, referred to here as wet and dry milling, utilized a conical screen mill. Milling of granulation in the wet state eliminated 1-10mm size agglomerates without affecting granule porosity or inducing further agglomeration. These millimeter-size agglomerates broke down during wet milling into moderately sized fragments larger than 125microm. In contrast, when milled after drying, these same 1-10mm-size agglomerates broke down predominantly into fine particles less than 125microm. Data from screen-less milling trials suggest that the mill screen served only as a classifier and did not significantly contribute to the route of breakage for either wet or dry milling. However, in the case of dry milling, mill screens with grated surface textures did result in fewer fines than non-grated screens. This may be a result of reduced residence time in the mill. Experiments varying the size fraction of feed material and the rotational speed of the mill's impeller identified impact attrition as the primary mechanism governing dry granule breakage. The findings in this study shed light into the fundamental breakdown behavior of pharmaceutical agglomerates and demonstrate how breakdown of wet agglomerates via a de-lumping step prior to drying can lead to a reduced level of fine particle generation during dry milling. PMID:17804181

Schenck, Luke R; Plank, Russell V

2008-02-01

274

Agglomeration kinetics of calcium sulphate hemihydrate crystals in sulpho-phosphoric solutions  

NASA Astrophysics Data System (ADS)

In the present study we aim at describing the agglomeration kinetics of calcium sulphate hemihydrate crystals, growing in concentrated sulpho-phosphoric solutions simulating an industrial process of phosphoric acid production. The experiments were carried out at 90°C, with 40 wt% P 2O 5 and different excesses in H 2SO 4. Population densities and supersaturation were determined by periodically removing suspension samples. Agglomeration kinetics were deduced from the volume growth rates and agglomeration kernel calculated from the population density moments of order 0, 1 and 2. Agglomeration rates are linear functions of supersaturation if the excess in H 2SO 4 is less than 2%. At 2% and 4%, agglomeration is maximum for relative supersaturations of 10% and 25%, respectively. Beyond an excess of 4% in H 2SO 4, agglomeration is low. At very high supersaturations, the aggregates are brittle due to crystal habit elongation. At last, it is shown that P 2O 5 loss is due rather to agglomeration than to incorporation of phosphate in the calcium sulphate hemihydrate crystal lattice.

El Moussaouiti, M.; Boistelle, R.; Bouhaouss, A.; Klein, J. P.

1996-11-01

275

Crude oil price forecasting based on hybridizing wavelet multiple linear regression model, particle swarm optimization techniques, and principal component analysis.  

PubMed

Crude oil prices do play significant role in the global economy and are a key input into option pricing formulas, portfolio allocation, and risk measurement. In this paper, a hybrid model integrating wavelet and multiple linear regressions (MLR) is proposed for crude oil price forecasting. In this model, Mallat wavelet transform is first selected to decompose an original time series into several subseries with different scale. Then, the principal component analysis (PCA) is used in processing subseries data in MLR for crude oil price forecasting. The particle swarm optimization (PSO) is used to adopt the optimal parameters of the MLR model. To assess the effectiveness of this model, daily crude oil market, West Texas Intermediate (WTI), has been used as the case study. Time series prediction capability performance of the WMLR model is compared with the MLR, ARIMA, and GARCH models using various statistics measures. The experimental results show that the proposed model outperforms the individual models in forecasting of the crude oil prices series. PMID:24895666

Shabri, Ani; Samsudin, Ruhaidah

2014-01-01

276

Analysis of river pollution data from low-flow period by means of multivariate techniques: a case study from the oil-shale industry region, northeastern Estonia.  

PubMed

The oil-shale industry has created serious pollution problems in northeastern Estonia. Untreated, phenol-rich leachate from semi-coke mounds formed as a by-product of oil-shale processing is discharged into the Baltic Sea via channels and rivers. An exploratory analysis of water chemical and microbiological data sets from the low-flow period was carried out using different multivariate analysis techniques. Principal component analysis allowed us to distinguish different locations in the river system. The riverine microbial community response to water chemical parameters was assessed by co-inertia analysis. Water pH, COD and total nitrogen were negatively related to the number of biodegradative bacteria, while oxygen concentration promoted the abundance of these bacteria. The results demonstrate the utility of multivariate statistical techniques as tools for estimating the magnitude and extent of pollution based on river water chemical and microbiological parameters. An evaluation of river chemical and microbiological data suggests that the ambient natural attenuation mechanisms only partly eliminate pollutants from river water, and that a sufficient reduction of more recalcitrant compounds could be achieved through the reduction of wastewater discharge from the oil-shale chemical industry into the rivers. PMID:12638742

Truu, Jaak; Heinaru, Eeva; Talpsep, Ene; Heinaru, Ain

2002-01-01

277

Magnetic agglomeration method for size control in the synthesis of magnetic nanoparticles  

DOEpatents

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.

Huber, Dale L. (Albuquerque, NM)

2011-07-05

278

Engineering development of selective agglomeration: Task 5, Bench- scale process testing  

SciTech Connect

Under the overall objectives of DOE Contract Engineering Development of Selective Agglomeration,'' there were a number of specific objectives in the Task 5 program. The prime objectives of Task 5 are highlighted below: (1) Maximize process performance in pyritic sulfur rejection and BTU recovery, (2) Produce a low ash product, (3) Compare the performance of the heavy agglomerant process based on diesel and the light agglomerant process using heptane, (4) Define optimum processing conditions for engineering design, (5) Provide first-level evaluation of product handleability, and (6) Explore and investigate process options/ideas which may enhance process performance and/or product handleability.

Not Available

1991-09-01

279

Engineering development of selective agglomeration: Task 5, Bench- scale process testing  

SciTech Connect

Under the overall objectives of DOE Contract ``Engineering Development of Selective Agglomeration,`` there were a number of specific objectives in the Task 5 program. The prime objectives of Task 5 are highlighted below: (1) Maximize process performance in pyritic sulfur rejection and BTU recovery, (2) Produce a low ash product, (3) Compare the performance of the heavy agglomerant process based on diesel and the light agglomerant process using heptane, (4) Define optimum processing conditions for engineering design, (5) Provide first-level evaluation of product handleability, and (6) Explore and investigate process options/ideas which may enhance process performance and/or product handleability.

Not Available

1991-09-01

280

Noise action plan of agglomerations: sustainable hypothesis or utopy?  

PubMed

European and Italian laws establish that agglomerations of more than 100 000 inhabitants must adopt an action plan in order to manage noise issues and effects. The plan aim is to reduce population exposure to environmental noise, which is defined as the outdoor sound created by human activities, including noise emitted by road traffic, rail traffic and air traffic, and noise from sites of industrial activity. Although acoustic pollution represents one of the main causes of annoyance for inhabitants of urban areas, the political agenda does not acknowledge it among the main environmental issues. Thus, acoustic reclamation is often considered a duty to be accomplished rather than a way to improve quality of life for citizens. Furthermore, financial resources are generally very poor while the acoustic critical situations are numerous and serious in terms of exceeding the limit. In this situation, what is the meaning of an urban area noise action plan? What are the concrete actions that municipalities can realise to reduce urban noise pollution? This study tries to answer these questions, starting from the analysis carried out for the action plan of the city of Turin. PMID:19841018

Magri, S L; Masera, S; Fogola, J

2009-12-01

281

Branched-linear and agglomerate protein polymers as vaccine platforms.  

PubMed

Many viral structural proteins and their truncated domains share a common feature of homotypic interaction forming dimers, trimers, and/or oligomers with various valences. We reported previously a simple strategy for construction of linear and network polymers through the dimerization feature of viral proteins for vaccine development. In this study, technologies were developed to produce more sophisticated polyvalent complexes through both the dimerization and oligomerization natures of viral antigens. As proof of concept, branched-linear and agglomerate polymers were made via fusions of the dimeric glutathione-s-transferase (GST) with either a tetrameric hepatitis E virus (HEV) protruding protein or a 24-meric norovirus (NoV) protruding protein. Furthermore, a monomeric antigen, either the M2e epitope of influenza A virus or the VP8* antigen of rotavirus, was inserted and displayed by the polymer platform. All resulting polymers were easily produced in Escherichia coli at high yields. Immunization of mice showed that the polymer vaccines induced significantly higher specific humoral and T cell responses than those induced by the dimeric antigens. Additional evidence in supporting use of polymer vaccines included the significantly higher neutralization activity and protective immunity of the polymer vaccines against the corresponding viruses than those of the dimer vaccines. Thus, our technology for production of polymers containing different viral antigens offers a strategy for vaccine development against infectious pathogens and their associated diseases. PMID:24985736

Wang, Leyi; Xia, Ming; Huang, Pengwei; Fang, Hao; Cao, Dianjun; Meng, Xiang-Jin; McNeal, Monica; Jiang, Xi; Tan, Ming

2014-09-01

282

Gravitational agglomeration of post-HCDA LMFBR nonspherical aerosols  

NASA Astrophysics Data System (ADS)

A theoretical investigation of collisional dynamics of two particle interactions in a gravitational field is reported. This research is unique in that it is the first attempt at modeling the hydrodynamic interactions between a nonspherical particle and a spherical particle undergoing gravitational collisions in an LMFBR environment. Basic definitions and expressions are developed for nonspherical particles and related to spherical particles by means of shape factors. Using volume equivalent diameter as the defining length in the gravitational collision kernel, the aerodynamic shape factor, k, the density correction factor, alpha, and the gravitational collision shape factor, beta, are used to correct the collision kernel for the case of collisions between aerosol agglomerates. The Navier-Stokes equation in oblate spheroidal coordinates is solved to model a nonspherical particle and then the dynamic equations for two particle motions are developed. A computer program NGCEFF is constructed, the Navier-Stokes equation is solved by the finite difference method, and the dynamical equations are solved by Gear's method. It is concluded that the aerosol gravitational collision shape factor can be determined by further theoretical work based on the concepts and methods developed in this dissertation.

Tuttle, R. F.

1980-12-01

283

COMPRESSION TECHNIQUES FOR BOUNDARY INTEGRAL EQUATIONS --OPTIMAL COMPLEXITY ESTIMATES \\Lambda  

E-print Network

and exploit perhaps in the best way the (typical) smoothness of the integral kernel away from the boundary) on the other hand, is that the former are essentially agglomeration techniques, while (WC) is more apt

284

Increased oil production and reserves utilizing secondary/tertiary recovery techniques on small reservoirs in the Paradox Basin, Utah, Class II  

SciTech Connect

The primary objective of this project is to enhance domestic petroleum production by field demonstration and technology transfer of an advanced-oil-recovery technology in the Paradox basin, southeastern Utah. If this project can demonstrate technical and economic feasibility, the technique can be applied to approximately 100 additional small fields in the Paradox basin alone, and result in increased recovery of 150 to 200 million barrels (23,850,000-31,800,000 m{sup 3}) of oil. This project is designed to characterize five shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation and choose the best candidate for a pilot demonstration project for either a waterflood or carbon-dioxide-miscible flood project. The field demonstration, monitoring of field performance, and associated validation activities will take place within the Navajo Nation, San Juan County, Utah.

Chidsey, Thomas C.

2000-07-28

285

THE PHYSICS OF PROTOPLANETESIMAL DUST AGGLOMERATES. V. MULTIPLE IMPACTS OF DUSTY AGGLOMERATES AT VELOCITIES ABOVE THE FRAGMENTATION THRESHOLD  

SciTech Connect

In recent years, a number of new experiments have advanced our knowledge on the early growth phases of protoplanetary dust aggregates. Some of these experiments have shown that collisions between porous and compacted agglomerates at velocities above the fragmentation threshold velocity can lead to growth of the compact body, when the porous collision partner fragments upon impact and transfers mass to the compact agglomerate. To obtain a deeper understanding of this potentially important growth process, we performed laboratory and drop tower experiments to study multiple impacts of small, highly porous dust-aggregate projectiles onto sintered dust targets. The projectile and target consisted of 1.5 {mu}m monodisperse, spherical SiO{sub 2} monomers with volume filling factors of 0.15 {+-} 0.01 and 0.45 {+-} 0.05, respectively. The fragile projectiles were accelerated by a solenoid magnet and combined with a projectile magazine with which 25 impacts onto the same spot on the target could be performed in vacuum. We measured the mass-accretion efficiency and the volume filling factor for different impact velocities between 1.5 and 6.0 m s{sup -1}. The experiments at the lowest impact speeds were performed in the Bremen drop tower under microgravity conditions to allow partial mass transfer also for the lowest adhesion case. Within this velocity range, we found a linear increase of the accretion efficiency with increasing velocity. In the laboratory experiments, the accretion efficiency increases from 0.12 to 0.21 in units of the projectile mass. The recorded images of the impacts showed that the mass transfer from the projectile to the target leads to the growth of a conical structure on the target after less than 100 impacts. From the images, we also measured the volume filling factors of the grown structures, which ranged from 0.15 (uncompacted) to 0.40 (significantly compacted) with increasing impact speed. The velocity dependency of the mass-transfer efficiency and the packing density of the resulting aggregates augment our knowledge of the aggregate growth in protoplanetary disks and should be taken into account for future models of protoplanetary dust growth.

Kothe, Stefan; Guettler, Carsten; Blum, Juergen, E-mail: s.kothe@tu-bs.d [Institut fuer Geophysik und extraterrestrische Physik, Technische Universitaet zu Braunschweig, Mendelssohnstr. 3, D-38106 Braunschweig (Germany)

2010-12-10

286

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

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

2012-01-01

287

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)

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.

Sivayoganathan, Mugunthan; Tan, Bo; Venkatakrishnan, Krishnan

2012-11-01

288

Discrete element modeling of the microstructure of fine particle agglomerates in sheared dilute suspension  

NASA Astrophysics Data System (ADS)

The fragmentation and restructuring under shear of agglomerates of fine mineral particles are studied with the Distinct Element Method. The model used takes into account contact forces, van der Waals forces, and hydrodynamic forces computed with the free-draining approximation. A loose initial agglomerate is submitted to a constant shear rate until reaching a quasi-stationary state, where the number, size and structure of fragment of agglomerates can be considered as constant. The influence of shear stress and size of particles on the characteristics of agglomerates at equilibrium is studied. Fragmentation is controlled by a non-dimensional number, depending on the radius of the particles, shear rate and maximal adhesion force.

Kimbonguila Manounou, A.; Rémond, S.

2014-10-01

289

An improvement in physicochemical properties of carvedilol through spherically agglomerated solid dispersions with PVP K30.  

PubMed

Spherically agglomerated solid dispersions of carvedilol (CAR) were prepared with polyvinyl-pyrrolidone (PVP) using acetone, water and dichloromethane as solvent, non-solvent and bridging liquid, respectively. The prepared agglomerates were evaluated for its percentage yield, drug content, morphology, thermal behavior, micromeritic properties, aqueous solubility and in vitro drug release. Differential scanning calorimetric and powder X-ray diffraction studies confirm that formulation process altered the crystalline nature of carvedilol. The recrystallized agglomerates exhibited significant increase (p < 0.05) in micromeritic properties than untreated carvedilol. Solubility and in vitro drug release studies indicated that the spherical agglomerates showed significant increase (p < 0.05) in solubility and dissolution rate than pure carvedilol alone. PMID:22568045

Tapas, Amit; Kawtikwar, Pravin; Sakarkar, Dinesh

2012-01-01

290

Identifying Agglomeration Spillovers: Evidence from Winners and Losers of Large Plant Openings  

E-print Network

We quantify agglomeration spillovers by comparing changes in total factor productivity (TFP) among incumbent plants in “winning” counties that attracted a large manufacturing plant and “losing” counties that were the new ...

Greenstone, Michael

291

A new derivation of the agglomerate size distribution for a constant coagulation kernel  

Microsoft Academic Search

The agglomerate size distribution for an assembly of primary particles coagulating with constant kernel K is usually derived from the solution of the relevant deterministic equations. We present an alternative stochastic approach to the problem.

S. Simons

1997-01-01

292

The surface properties of nanoparticles determine the agglomeration state and the size of the particles under physiological conditions  

PubMed Central

Summary Due to the recent widespread application of nanomaterials to biological systems, a careful consideration of their physiological impact is required. This demands an understanding of the complex processes at the bio–nano interface. Therefore, a comprehensive and accurate characterization of the material under physiological conditions is crucial to correlate the observed biological impact with defined colloidal properties. As promising candidates for biomedical applications, two SiO2-based nanomaterial systems were chosen for extensive size characterization to investigate the agglomeration behavior under physiological conditions. To combine the benefits of different characterization techniques and to compensate for their respective drawbacks, transmission electron microscopy, dynamic light scattering and asymmetric flow field-flow fractionation were applied. The investigated particle systems were (i) negatively charged silica particles and (ii) poly(organosiloxane) particles offering variable surface modification opportunities (positively charged, polymer coated). It is shown that the surface properties primarily determine the agglomeration state of the particles and therefore their effective size, especially under physiological conditions. Thus, the biological identity of a nanomaterial is clearly influenced by differentiating surface properties. PMID:25383289

Galla, Hans-Joachim; Kirkpatrick, C James; Stauber, Roland H

2014-01-01

293

INCREASED OIL PRODUCTION AND RESERVES UTILIZING SECONDARY/TERTIARY RECOVERY TECHNIQUES ON SMALL RESERVOIRS IN THE PARADOX BASIN, UTAH  

SciTech Connect

The Paradox Basin of Utah, Colorado, and Arizona contains nearly 100 small oil fields producing from shallow-shelf carbonate buildups or mounds within the Desert Creek zone of the Pennsylvanian (Desmoinesian) Paradox Formation. These fields typically have one to four wells with primary production ranging from 700,000 to 2,000,000 barrels (111,300-318,000 m{sup 3}) of oil per field at a 15 to 20 percent recovery rate. Five fields in southeastern Utah were evaluated for waterflood or carbon-dioxide (CO{sub 2})-miscible flood projects based upon geological characterization and reservoir modeling. Geological characterization on a local scale focused on reservoir heterogeneity, quality, and lateral continuity as well as possible compartmentalization within each of the five project fields. The Desert Creek zone includes three generalized facies belts: (1) open-marine, (2) shallow-shelf and shelf-margin, and (3) intra-shelf, salinity-restricted facies. These deposits have modern analogs near the coasts of the Bahamas, Florida, and Australia, respectively, and outcrop analogs along the San Juan River of southeastern Utah. The analogs display reservoir heterogeneity, flow barriers and baffles, and lithofacies geometry observed in the fields; thus, these properties were incorporated in the reservoir simulation models. Productive carbonate buildups consist of three types: (1) phylloid algal, (2) coralline algal, and (3) bryozoan. Phylloid-algal buildups have a mound-core interval and a supra-mound interval. Hydrocarbons are stratigraphically trapped in porous and permeable lithotypes within the mound-core intervals of the lower part of the buildups and the more heterogeneous supramound intervals. To adequately represent the observed spatial heterogeneities in reservoir properties, the phylloid-algal bafflestones of the mound-core interval and the dolomites of the overlying supra-mound interval were subdivided into ten architecturally distinct lithotypes, each of which exhibits a characteristic set of reservoir properties obtained from outcrop analogs, cores, and geophysical logs. The Anasazi and Runway fields were selected for geostatistical modeling and reservoir compositional simulations. Models and simulations incorporated variations in carbonate lithotypes, porosity, and permeability to accurately predict reservoir responses. History matches tied previous production and reservoir pressure histories so that future reservoir performances could be confidently predicted. The simulation studies showed that despite most of the production being from the mound-core intervals, there were no corresponding decreases in the oil in place in these intervals. This behavior indicates gravity drainage of oil from the supra-mound intervals into the lower mound-core intervals from which the producing wells' major share of production arises. The key to increasing ultimate recovery from these fields (and similar fields in the basin) is to design either waterflood or CO{sub 2}-miscible flood projects capable of forcing oil from high-storage-capacity but low-recovery supra-mound units into the high-recovery mound-core units. Simulation of Anasazi field shows that a CO{sub 2} flood is technically superior to a waterflood and economically feasible. For Anasazi field, an optimized CO{sub 2} flood is predicted to recover a total 4.21 million barrels (0.67 million m3) of oil representing in excess of 89 percent of the original oil in place. For Runway field, the best CO{sub 2} flood is predicted to recover a total of 2.4 million barrels (0.38 million m3) of oil representing 71 percent of the original oil in place. If the CO{sub 2} flood performed as predicted, it is a financially robust process for increasing the reserves in the many small fields in the Paradox Basin. The results can be applied to other fields in the Rocky Mountain region, the Michigan and Illinois Basins, and the Midcontinent.

Thomas C. Chidsey, Jr.

2002-11-01

294

Pilot plant testing of IGT`s two-stage fluidized-bed\\/cyclonic agglomerating combustor  

Microsoft Academic Search

The Institute of Gas Technology (IGT) is conducting a multi-year experimental program to develop and test, through pilot-scale operation, IGT`s two-stage fluidized-bed\\/cyclonic agglomerating combustor (AGGCOM). The AGGCOM process is based on combining the fluidized-bed agglomeration and gasification technology with the cyclonic combustion technology, both of which have been developed at IGT over many years. AGGCOM is a unique and extremely

A. Rehmat; M. C. Mensinger; T. L. Richardson

1993-01-01

295

Nanostructured cerium oxide: preparation and properties of weakly-agglomerated powders  

Microsoft Academic Search

Nanocrystalline powders of cerium oxide were prepared from cerium(III) nitrate solution by a two-stage precipitation process which yielded weakly-agglomerated powders with a crystallite size smaller than 5nm. Hydrogen peroxide was added to cerium nitrate at 5°C to slowly oxidise Ce3+ to Ce4+ and thereby initiate homogeneous precipitation with the formation of dense spherical agglomerates. The precipitation process was completed by

Boro Djuri?i?; Stephen Pickering

1999-01-01

296

Dispersion of TiO2 Nanoparticle Agglomerates by Pseudomonas aeruginosa? †  

PubMed Central

Engineered nanoparticles are increasingly incorporated into consumer products and are emerging as potential environmental contaminants. Upon environmental release, nanoparticles could inhibit bacterial processes, as evidenced by laboratory studies. Less is known regarding bacterial alteration of nanoparticles, including whether bacteria affect physical agglomeration states controlling nanoparticle settling and bioavailability. Here, the effects of an environmental strain of Pseudomonas aeruginosa on TiO2 nanoparticle agglomerates formed in aqueous media are described. Environmental scanning electron microscopy and cryogenic scanning electron microscopy visually demonstrated bacterial dispersion of large agglomerates formed in cell culture medium and in marsh water. For experiments in cell culture medium, quantitative image analysis verified that the degrees of conversion of large agglomerates into small nanoparticle-cell combinations were similar for 12-h-growth and short-term cell contact experiments. Dispersion in cell growth medium was further characterized by size fractionation: for agglomerated TiO2 suspensions in the absence of cells, 81% by mass was retained on a 5-?m-pore-size filter, compared to only 24% retained for biotic treatments. Filtrate cell and agglomerate sizes were characterized by dynamic light scattering, revealing that the average bacterial cell size increased from 1.4 ?m to 1.9 ?m because of nano-TiO2 biosorption. High-magnification scanning electron micrographs showed that P. aeruginosa dispersed TiO2 agglomerates by preferential biosorption of nanoparticles onto cell surfaces. These results suggest a novel role for bacteria in the environmental transport of engineered nanoparticles, i.e., growth-independent, bacterially mediated size and mass alterations of TiO2 nanoparticle agglomerates. PMID:20851981

Horst, Allison M.; Neal, Andrea C.; Mielke, Randall E.; Sislian, Patrick R.; Suh, Won Hyuk; Madler, Lutz; Stucky, Galen D.; Holden, Patricia A.

2010-01-01

297

Interpretation of gas–liquid reactive crystallization data using a size-independent agglomeration model  

Microsoft Academic Search

A CO2–BaCl2–H2O gas–liquid reactive crystallization system, depicted by a size-independent agglomeration model, was successfully used to explore the crystallization kinetics of barium carbonate crystals. The growth kinetics shows that growth rate is proportional to a 1.85 order of relative supersaturation and decreases with an increase in pH value. The agglomeration kernel is nearly proportional to the growth rate of barium

Pao-Chi Chen; S. M. Liu; C. J. Jang; R. C. Hwang; Y. L. Yang; J. S. Lee; J. S. Jang

2003-01-01

298

Agglomeration kinetics of calcium sulphate hemihydrate crystals in sulpho-phosphoric solutions  

Microsoft Academic Search

In the present study we aim at describing the agglomeration kinetics of calcium sulphate hemihydrate crystals, growing in concentrated sulpho-phosphoric solutions simulating an industrial process of phosphoric acid production. The experiments were carried out at 90°C, with 40 wt% P2O5 and different excesses in H2SO4. Population densities and supersaturation were determined by periodically removing suspension samples. Agglomeration kinetics were deduced

M. El Moussaouiti; R. Boistelle; A. Bouhaouss; J. P. Klein

1996-01-01

299

Effects of operating conditions on agglomeration and habit of paracetamol crystals in anti-solvent crystallization  

NASA Astrophysics Data System (ADS)

Effects of agitation speed and feeding rate on agglomeration and habit of paracetamol crystals in anti-solvent crystallization from water-acetone mixture are reported. Water is used as anti-solvent and is added in a semi-batch manner to a baffled 1-l crystallizer equipped with a marine-type impeller. A simple new method to characterize agglomeration degree has been proposed. Results show that agglomeration degree of crystals depends on particle size and elevated agitation reduces agglomeration degree of big particles. Particle mean size exhibits a maximum with increasing agitation intensity in the range of 200-600 rpm, which is explained from the perspective of anti-solvent dispersion and crystal agglomeration/disruption. Agglomeration degree of products deteriorates with increasing feeding rate ranging from 1 to 20 g/min due to enhanced nucleation. Crystal habit changes when feeding rate is altered, mainly in the faces of [0 0 1] and [1 1 0]. Focused beam reflectance measurement (FBRM) was used to monitor indirectly the particle size distribution in situ. The data demonstrated that FBRM may potentially be used as a tool to control crystallization process.

Yu, Z. Q.; Tan, R. B. H.; Chow, P. S.

2005-06-01

300

Effect of extraction technique on the content and antioxidant activity of crude extract of Anacyclus clavatus flowers and their essential oil composition.  

PubMed

Anacyclus clavatus is a plant used as food and remedy. The objective of this work was to study the effect of extraction technique on the antioxidant property, total phenol and flavonoid contents of crude extracts from A. clavatus flowers and their essential oil composition. 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, ferric-reducing power, ?-carotene and total antioxidant capacity assays have demonstrated the significant antioxidant ability of different crude extracts obtained by using the following extraction methods: Soxhlet, microwave heating, heat reflux (HRE) and maceration. The activity of the extract obtained by HRE was the highest (112.06 ± 2.89 ?g/mL) evaluated by the DPPH assay. Extraction of essential oil was performed by microwave-assisted hydro-distillation (MAHD) and by hydro-distillation (HD). A significant difference was observed in both essential oils, despite the common main family and major constituents, such as artemisia ketone (10.0 ± 0.8% for MAHD vs. 6.5 ± 0.5 for HD) and pinocarvone (4.1 ± 0.4% for MAHD vs. 1.1 ± 0.1% for HD). PMID:25115624

Aliboudhar, Hamza; Tigrine-Kordjani, Nacéra

2014-12-01

301

Development of a fast analytical tool to identify oil spillages employing infrared spectral indexes and pattern recognition techniques.  

PubMed

A fast analytical tool based on attenuated total reflectance mid-IR spectrometry is presented to evaluate the origin of spilled hydrocarbons and to monitor their fate on the environment. Ten spectral band ratios are employed in univariate and multivariate studies (principal components analysis, cluster analysis, density functions - potential curves - and Kohonen self organizing maps). Two indexes monitor typical photooxidation processes, five are related to aromatic characteristics and three study aliphatic and branched chains. The case study considered here comprises 45 samples taken on beaches (from 2002 to 2005) after the Prestige carrier accident off the Galician coast and 104 samples corresponding to weathering studies deployed for the Prestige's fuel, four typical crude oils and a fuel oil. The univariate studies yield insightful views on the gross chemical evolution whereas the multivariate studies allow for simple and straightforward elucidations on whether the unknown samples match the Prestige's fuel. Besides, a good differentiation on the weathering patterns of light and heavy products is obtained. PMID:18371626

Fresco-Rivera, P; Fernández-Varela, R; Gómez-Carracedo, M P; Ramírez-Villalobos, F; Prada, D; Muniategui, S; Andrade, J M

2007-11-30

302

Decision-Making for the Optimal Strategy of Population Agglomeration in Urban Planning with Path-Converged Design  

Microsoft Academic Search

\\u000a The chapter aims first to identify existing population agglomeration and its efficiency, and second to simulate decision-making\\u000a for the optimal migration strategy in urban planning to eliminate inefficiency among cities in China. First, identification\\u000a based on path-converged design reveals inefficiency in existing population agglomeration in China because the population mostly\\u000a agglomerates to cities with urbanization levels lower than 0.35 and

Bing Xu; Junzo Watada

303

Increased oil production and reserves utilizing secondary/tertiary recovery techniques on small reservoirs in the Paradox basin, Utah. Technical progress report, July 1--September 30, 1995  

SciTech Connect

The primary objective of this project is to enhance domestic petroleum production by demonstration and technology transfer of an advanced oil recovery technology in the Paradox basin, southeastern Utah. If this project can demonstrate technical and economic feasibility, the technique can be applied to approximately 100 additional small fields in the Paradox basin alone, and result in increased recovery of 150 to 200 million barrels of oil. This project is designed to characterize five shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation and choose the best candidate for a pilot demonstration project for either a waterflood or carbon dioxide-(CO{sub 2}-) flood project. The field demonstration, monitoring of field performance, and associated validation activities will take place in the Paradox basin within the Navajo Nation. The results of this project will be transferred to industry and other researchers through a petroleum extension service, creation of digital databases for distribution, technical workshops and seminars, field trips, technical presentations at national and regional professional meetings, and publication in newsletters and various technical or trade journals. Four activities continued this quarter as part of the geological and reservoir characterization of carbonate mound buildups in the Paradox basin: (1) field studies, (2) development well completion operations, (3) reservoir analysis and modeling, and (4) technology transfer. This paper reviews the status.

Allison, M.L.

1995-12-01

304

Increased oil production and reserves utilizing secondary/tertiary recovery techniques on small reservoirs in the Paradox Basin, Utah. Technical progress report, January 1--March 31, 1996  

SciTech Connect

The primary objective of this project is to enhance domestic petroleum production by demonstration and technology transfer of an advanced oil recovery technology in the Paradox basin, southeastern Utah. If this project can demonstrate technical and economic feasibility, the technique can be applied to approximately 100 additional small fields in the Paradox basin alone, and result in increased recovery of 150 to 200 million barrels of oil. This project is designed to characterize five shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation and choose the best candidate for a pilot demonstration project for either a waterflood or carbon dioxide-(CO{sub 2}-)flood project. The field demonstration, monitoring of field performance, and associated validation activities will take place in the Paradox basin within the Navajo Nation. The results of this project will be transferred to industry and other researchers through a petroleum extension service, creation of digital databases for distribution, technical workshops and seminars, field trips, technical presentations at national and regional professional meetings, and publication in newsletters and various technical or trade journals.

Allison, M.L.

1996-04-30

305

Increased oil production and reserves utilizing secondary/tertiary recovery techniques on small reservoirs in the Paradox basin, Utah. Final technical progress report, October 1--December 31, 1995  

SciTech Connect

The primary objective of this project is to enhance domestic petroleum production by demonstration and technology transfer of an advanced oil recovery technology in the Paradox basin, southeastern Utah. If this project can demonstrate technical and economic feasibility, the technique can be applied to approximately 100 additional small fields in the Paradox basin alone, and result in increased recovery of 150 to 200 million barrels of oil. This project is designed to characterize five shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation and choose the best candidate for a pilot demonstration project for either a waterflood or carbon dioxide-(CO{sub 2}) flood project. The field demonstration, monitoring of field performance, and associated validation activities will take place in the Paradox basin within the Navajo Nation. The results of this project will be transferred to industry and other researchers through a petroleum extension service, creation of digital databases for distribution, technical workshops and seminars, field trips, technical presentations at national and regional professional meeting, and publication in newsletters and various technical or trade journals. Five activities continued this quarter as part of the geological and reservoir characterization of carbonate mound buildups in the Paradox basin: (1) regional facies evaluation, (2) evaluation of outcrop analogues, (3) field-scale geologic analysis, (4) reservoir analysis, and (5) technology transfer.

Allison, M.L.

1996-01-15

306

Increased oil production and reserves utilizing secondary/teritiary recovery techniques on small reservoirs in the Paradox Basin, Utah. Quarterly report, July 1 - September 30, 1996  

SciTech Connect

The primary objective of this project is to enhance domestic petroleum production by demonstration and technology transfer of an advanced oil recovery technology in the Paradox basin, southeastern Utah. If this project can demonstrate technical and economic feasibility, the technique can be applied to approximately 100 additional small fields in the Paradox basin alone, and result in increased recovery of 150 to 200 million barrels of oil. This project is designed to characterize five shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation and choose the best candidate for a pilot demonstration project for either a waterflood or carbon dioxide flood project. The field demonstration, monitoring of field performance, and associated validation activities will take place in the Paradox basin within the Navajo Nation. The results of this project will be transferred to industry and other researchers through a petroleum extension service, creation of digital databases for distribution, technical workshops and seminars, field trips, technical presentations at national and regional professional meeting, and publication in newsletters and various technical or trade journals. Four activities continued this quarter as part of the geological and reservoir characterization: (1) interpretation of outcrop analogues; (2) reservoir mapping, (3) reservoir engineering analysis of the five project fields; and (4) technology transfer.

Allison, M.L.

1996-10-01

307

Increased oil production and reserves utilizing secondary/tertiary recovery techniques on small reservoirs in the Paradox basin, Utah. Technical progress report, April 1, 1995--June 30, 1995  

SciTech Connect

The primary objective of this project is to enhance domestic petroleum production by demonstration and technology transfer of an advanced oil recovery technology in the Paradox basin, southeastern Utah. If this project can demonstrate technical and economic feasibility, the technique can be applied to approximately 100 additional small fields in the Paradox basin alone, and result in increased recovery of 150 to 200 million barrels of oil. This project is designed to characterize five shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation and choose the best candidate for a pilot demonstration project for either a waterflood or carbon dioxide-flood project. The field demonstration, monitoring of field performance, and associated validation activities will take place in the Paradox basin within the Navajo Nation. The results of this project will be transferred to industry and other researchers through a petroleum extension service, creation of digital databases for distribution, technical workshops and seminars, field trips, technical presentations at national and regional professional meetings, and publication in newsletters and various technical or trade journals.

Allison, M.L.

1995-07-14

308

OIL SLICK DISPERSAL MECHANICS  

EPA Science Inventory

This study investigates the spreading and dissolution behavior of small oil slicks formed from spills of 12 oils. The increases in area covered by the oils during spreading experiments were determined using photographic techniques. Spreading equations were derived and used to cor...

309

Microbial enhanced oil recovery  

Microsoft Academic Search

This book focuses on a variety of enhanced oil recovery (EOR) processes in various stages of development. Perhaps the youngest of these techniques is microbial enhanced oil recovery (MEOR), which has only recently been accepted as a viable alternative to other EOR processes. Because a large percentage of original oil in place (â¼ 70%) is left in a reservoir at

Yen

1990-01-01

310

SELF-POTENTIAL PROFILING - A NEW TECHNIQUE FOR DETERMINATION OF HEAT MOVEMENT IN A THERMAL OIL RECOVERY FLOOD  

Microsoft Academic Search

Self-potential profiling, a technique long used to locate mineral deposits, has recently been found by various investigators to be an excellent tool for locating and delineating buried geothermal reservoirs in clastic and pyroclastic environments. Laboratory experiments indicate that application of heat to the surface of various core samples results in an instantaneous generation of electric current, due to thermoelectric coupling

M. H. Dorfman; M. M. Oskay; M. P. Gaddis

1977-01-01

311

Changes in agglomeration of fullerenes during ingestion and excretion in Thamnocephalus platyurus.  

PubMed

The crustacean Thamnocephalus platyurus was exposed to aqueous suspensions of fullerenes C(60) and C(70) . Aqueous fullerene suspensions were formed by stirring C(60) and C(70) as received from a commercial vendor in deionized water (termed aqu/C(60) and aqu/C(70) ) for approximately 100 d. The Z-average (mean hydrodynamic) diameters of aqu/C(60) and aqu/C(70) aggregates as measured by dynamic light scattering were 517?±?21?nm and 656?±?39?nm (mean?±?95% confidence limit), respectively. Exposure of T. platyurus to fullerene suspensions resulted in the formation of dark masses in the digestive track visible under a stereo microscope (×40 magnification). Fullerene ingestion over 1?h of exposure was quantitatively determined after extraction and analysis by high-performance liquid chromatography-mass spectrometry (HPLC-MS). One-hour exposures (at 3?mg/L and 6?mg/L) resulted in aqu/C(60) burdens of 2.7?±?0.4?µg/mg and 6.8?±?1.5?µg/mg wet weight, respectively. Thin-section transmission electron microscopy (TEM) images of aqu/C(60) -exposed T. platyurus showed the formation in the gut of fullerene agglomerates (5-10?µm) that were an order of magnitude larger than the suspended fullerene agglomerates. Upon excretion, the observed fullerene agglomerates were in the 10- to 70-µm size range and settled to the bottom of the incubation wells. In contrast to the control polystyrene microspheres, which dispersed after depuration, the aqu/C(60) agglomerates (greater than two orders of magnitude larger than the suspended fullerenes) remained agglomerated for up to six months. When exposed to fullerenes, T. platyurus shows the potential to influence agglomerate size and may facilitate movement of these nanoparticles from the water column into sediment. PMID:21309021

Patra, Manomita; Ma, Xin; Isaacson, Carl; Bouchard, Dermont; Poynton, Helen; Lazorchak, James M; Rogers, Kim R

2011-04-01

312

Increased oil production and reserves from improved completion techniques in the Bluebell field, Uinta Basin, Utah. Annual report, October 1, 1995--September 30, 1996  

SciTech Connect

The Bluebell field is productive from the Tertiary lower Green River and Wasatch Formations of the Uinta Basin, Utah. The productive interval consists of thousands of feet of interbedded fractured clastic and carbonate beds deposited in a fluvial-dominated lacustrine environment. Wells in the Bluebell field are typically completed by perforating 40 or more beds over 1,000 to 3,000 vertical feet (300-900 m), then stimulating the entire interval. This completion technique is believed to leave many potentially productive beds damaged and/or untreated, while allowing water-bearing and low-pressure (thief) zones to communicate with the wellbore. Geologic and engineering characterization has been used to define improved completion techniques. A two-year characterization study involved detailed examination of outcrop, core, well logs, surface and subsurface fractures, produced oil-field waters, engineering parameters of the two demonstration wells, and analysis of past completion techniques and effectiveness. The characterization study resulted in recommendations for improved completion techniques and a field-demonstration program to test those techniques. The results of the characterization study and the proposed demonstration program are discussed in the second annual technical progress report. The operator of the wells was unable to begin the field demonstration this project year (October 1, 1995 to September 20, 1996). Correlation and thickness mapping of individual beds in the Wasatch Formation was completed and resulted in a. series of maps of each of the individual beds. These data were used in constructing the reservoir models. Non-fractured and fractured geostatistical models and reservoir simulations were generated for a 20-square-mile (51.8-km{sup 2}) portion of the Bluebell field. The modeling provides insights into the effects of fracture porosity and permeability in the Green River and Wasatch reservoirs.

Morgan, C.D.; Allison, M.L.

1997-08-01

313

Heterogeneous Shallow-Shelf Carbonate Buildups in the Paradox Basin, Utah and Colorado: Targets for Increased Oil Production and Reserves Using Horizontal Drilling Techniques  

SciTech Connect

The project's primary objective was to enhance domestic petroleum production by demonstration and transfer of horizontal drilling technology in the Paradox Basin, Utah, Colorado, Arizona, and New Mexico. If this project can demonstrate technical and economic feasibility, then the technique can be applied to approximately 100 additional small fields in the Paradox Basin alone, and result in increased recovery of 25 to 50 million barrels (4-8 million m3) of oil. This project was designed to characterize several shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation, choose the best candidate(s) for a pilot demonstration project to drill horizontally from existing vertical wells, monitor well performance(s), and report associated validation activities.

Chidsey, Jr., Thomas C.; Eby, David E.; Wray, Laural L.

2001-11-26

314

Heterogeneous Shallow-Shelf Carbonate Buildups in the Paradox Basin, Utah and Colorado: Targets for Increased Oil Production and Reserves Using Horizontal Drilling Techniques  

SciTech Connect

The primary objective of this project was to enhance domestic petroleum production by demonstration and transfer of horizontal drilling technology in the Paradox basin, Utah, Colorado, Arizona, and New Mexico. If this project can demonstrate technical and economic feasibility, then the technique can be applied to approximately 100 additional small fields in the Paradox basin alone, and result in increased recovery of 25 to 50 million barrels (40-80 million m3) of oil. This project was designed to characterize several shallow-shelf carbonate reservoirs in the Pennsylvania (Desmoinesian) Paradox Formation, choose the best candidate(s) for a pilot demonstration project to drill horizontally from existing vertical wells, monitor well performances, and report associated validation activities.

Chidsey, Thomas C. Jr.; Eby, David E.; Wray, Laura L.

2001-04-19

315

Cu-Doping Effects in CdI2Nanocrystals: The Role of Cu-Agglomerates  

PubMed Central

Cu-doping effects in CdI2nanocrystals are studied experimentally. We use the photostimulated second harmonic generation (PSSHG) as a tool to investigate the effects. It is found that the PSSHG increases with increasing Cu content up to 0.6% and then decreases due to the formation of the Cu-agglomerates. The PSSHG for the crystal with Cu content higher than 1% reduces to that for the undoped CdI2crystal. The results suggest that a crucial role of the Cu-metallic agglomerates is involved in the processes as responsible for the observed effects. PMID:20596399

2009-01-01

316

Advanced analytical mass spectrometric techniques and bioassays to characterize untreated and ozonated oil sands process-affected water.  

PubMed

Oil sands process-affected water (OSPW) is a toxic and poorly biodegradable mixture of sand, silt, heavy metals, and organics. In this study, qualitative and quantitative comparisons of naphthenic acids (NAs) were done using ultraperformance liquid chromatography time-of-flight mass spectrometry (UPLC TOF-MS), Fourier transform ion cyclotron resonance (FT-ICR) MS, and ion mobility spectrometry (IMS). The unique combination of these analyses allowed for the determination and correlation of NAs, oxidized NAs, and heteroatom (sulfur or nitrogen) NAs. Despite its lower resolution, UPLC-TOF MS was shown to offer a comparable level of reliability and precision as the high resolution FT-ICR MS. Additionally, the impacts of ozonation (35 mg/L utilized ozone dose) and subsequent NAs degradation on OSPW toxicity were assessed via a collection of organisms and toxicity end points using Vibrio fischeri (nonspecific), specific fish macrophage antimicrobial responses, and fish olfactory responses. Fish macrophages exposed to ozonated OSPW for 1 week showed higher production of reactive oxygen and nitrogen intermediates; however, after 12 weeks the responses were reduced significantly. Fish olfactory tests suggested that OSPW interfered with their perception of odorants. Current results indicate that the quantification of NAs species, using novel analytical methods, can be combined with various toxicity methods to assess the efficiency of OSPW treatment processes. PMID:25211339

Sun, Nian; Chelme-Ayala, Pamela; Klamerth, Nikolaus; McPhedran, Kerry N; Islam, Md Shahinoor; Perez-Estrada, Leonidas; Drzewicz, Przemys?aw; Blunt, Brian J; Reichert, Megan; Hagen, Mariel; Tierney, Keith B; Belosevic, Miodrag; Gamal El-Din, Mohamed

2014-10-01

317

In-Situ Agglomeration and De-agglomeration by Milling of Nano-Engineered Lubricant Particulate Composites for Cold Spray Deposition  

NASA Astrophysics Data System (ADS)

Nano-engineered self-lubricating particles comprised of hexagonal-boron-nitride powder (hBN) encapsulated in nickel have been developed for cold spray coating of aluminum components. The nickel encapsulant consists of several nano-sized layers, which are deposited on the hBN particles by electroless plating. In the cold spray deposition, the nickel becomes the matrix in which hBN acts as the lubricant. The coating demonstrated a very promising performance by reducing the coefficient of friction by almost 50% and increasing the wear resistance more than tenfold. The coatings also exhibited higher bond strength, which was directly related to the hardenability of the particles. During the encapsulation process, the hBN particles agglomerate and form large clusters. De-agglomeration has been studied through low- and high-energy ball milling to create more uniform and consistent particle sizes and to improve the cold spray deposition efficiency. The unmilled and milled particles were characterized with Scanning Electron Microscopy, Energy-Dispersive X-Ray Spectroscopy, BET, and hardness tests. It was found that in low-energy ball milling, the clusters were compacted to a noticeable extent. However, the high-energy ball milling resulted in breakup of agglomerations and destroyed the nickel encapsulant.

Neshastehriz, M.; Smid, I.; Segall, A. E.

2014-10-01

318

Emission characteristics of organic and heavy metal pollutants in fluidized bed incineration during the agglomeration/defluidization process  

SciTech Connect

The accumulation of adhesive materials may generate agglomerates during incineration. These agglomerates affect fluidization behavior and cause the formation of secondary pollutants. However, the impact of agglomeration on the emission of organics and heavy metals has seldom been investigated. Accordingly, this work focuses on the preparation of different synthetic wastes to simulate the generation of agglomerates, as well as the effects of various alkali metals, alkaline earth metals, and operating temperatures on the formation of pollutants. The experimental results indicate that defluidization time declines as the concentration of sodium increases, and that alkaline earth metals (Mg and Ca) inhibit agglomeration. Concentrations of organic pollutants gradually increase with operating time, indicating that the size of the agglomerate gradually increases, reducing the quality of fluidization and the efficiency of combustion. After defluidization, the temperature on the surface of the sand bed increases, thereby reducing the concentrations of organics, but it remains higher than that of blank operation (without Na addition). Furthermore, concentrations of three volatile metals (Cd, Pb, Cr) follow similar trends with operating time. Independent of whether the agglomerate is formed, the concentrations of emitted heavy metals are similar. After defluidization, the emitted concentration increases, because the system is transformed to the phase of the fixed bed. The abundant silica sand does not capture the heavy metals released from waste combustion. The increasing temperature of the surface of the sand bed significantly enhances the emission of heavy metals. Accordingly, the emitted organic and heavy metal pollutants behave differently during agglomeration and defluidization.

Lin, Chiou-Liang; Wey, Ming-Yen; Yu, Wu-Jung [Department of Environmental Engineering, National Chung-Hsing University, Taichung 402, Taiwan (ROC)

2005-11-01

319

Population balance modelling for a flow induced phase inversion based granulation in a two-dimensional rotating agglomerator  

Microsoft Academic Search

A novel two-dimensional rotating agglomerator was developed to carry out the flow induced phase inversion (FIPI) based granulation. The process in this agglomerator shows that a continuous paste flow (mixed with liquid binder and primary particles) is extruded into the interstice of two relatively rotating disks, as the paste becomes solidified due to the loss of heat to the disks,

L. Liu; G. Akay; L. Tong

2011-01-01

320

Improved models for fractal colloidal agglomeration: computationally efficient algorithms  

Microsoft Academic Search

A variety of modeling techniques for the population balances resulting from particle coagulation were examined. The simplified models using the non-uniform discretization scheme were compared to uniform discrete models. Further, new algorithms that incorporate a non-uniform discretization were developed. The uniform discrete population balance was used as the basis of comparison as it considers a continuous distribution of size classes

Jin-Wook Kim; Timothy A. Kramer

2005-01-01

321

Influence of decomposition parameters on agglomeration process and total soda content in precipitated Al(OH) 3  

NASA Astrophysics Data System (ADS)

Grain size composition of precipitated Al(OH) 3 is dependent on the mechanism of decomposition process of the caustic solution which determines crystal growth process, agglomeration process and secondary nucleation. Because the literature data shows that the growth rate is very low, the agglomeration process plays an important role in increasing the initial particle size. On the other hand, the agglomeration process enables the inclusion of impurities by the grain boundary of sticking Al(OH) 3 particles, above all, the inclusion of soda Na 2O. In this paper we investigate the influence of caustic soda concentration Na 2O (c), that is the supersaturation of the solution, seed charge and seed grain size on the agglomeration and secondary nucleation processes and total soda content in precipitated Al(OH) 3. The results have shown that the factor which causes the increase of the agglomeration process also causes the increase of total soda content in precipitated Al(OH) 3.

Blagojevi?, I.; Ble?i?, D.; Vasiljevi?, R.

1999-04-01

322

Microbial Enhanced Oil Recovery (MEOR)  

Microsoft Academic Search

Microbial enhanced oil recovery (MEOR) represents the use of microorganisms to extract the remaining oil from reservoirs. This technique has the potential to be cost-efficient in the extraction of oil remained trapped in capillary pores of the formation rock or in areas not swept by the classical or modern enhanced oil recovery (EOR) methods, such as combustion, steams, miscible displacement,

I. Lazar; I. G. Petrisor; T. F. Yen

2007-01-01

323

Simple modeling of the thermal history of d.c plasma sprayed agglomerated nanosized zirconia particles  

E-print Network

Simple modeling of the thermal history of d.c plasma sprayed agglomerated nanosized zirconia, Russia Abstract: In this work, are presented the results of a model coupling both dynamic and thermal histories of a single zirconia particle injected into a d.c plasma jet. The model developed calculates

Paris-Sud XI, Université de

324

Colloidal agglomerates in tank sludge: Impact on waste processing. 1997 annual progress report  

SciTech Connect

'Disposal of millions of gallons of existing radioactive wastes is a major remediation problem for the Department of Energy (DOE). Although radionuclides are the most hazardous waste con- stituents. the components of greatest concern from a waste processing standpoint are insoluble sludges consisting of submicron colloidal particles. Depending on processing conditions, these colloidal particles can form agglomerate networks that could clog transfer lines or interfere with solid-liquid separations such as settle-decant operations. Under different conditions, the particles can be dispersed to form very fine suspended particles that will not create sediment in settle- decant steps and that can foul and contaminate downstream treatment components including ion exchangers or filtrations systems. Given the wide range of tank chemistries present at Hanford and other DOE sites, it is impractical to measure the properties of all potential processing conditions to design effective treatment procedures. Instead. a framework needs to be established to allow sludge property trends to be predicted on a sound scientific basis. The scientific principles of greatest utility in characterizing, understanding, and controlling the physical properties of sludge fall in the realm of colloid chemistry. The objectives of this work are to accomplish the following: understand the factors controlling the nature and extent of colloidal agglomeration under expected waste processing conditions determine how agglomeration phenomena influence physical properties relevant to waste processing including rheology, sedimentation. and filtration develop strategies for optimizing processing conditions via control of agglomeration phenomena.'

Virden, J.W.

1997-06-01

325

Do Universities Generate Agglomeration Spillovers? Evidence from Endowment Value Shocks. NBER Working Paper No. 15299  

ERIC Educational Resources Information Center

In this paper we quantify the extent and magnitude of agglomeration spillovers from a formal institution whose sole mission is the creation and dissemination of knowledge--the research university. We use the fact that universities follow a fixed endowment spending policy based on the market value of their endowments to identify the causal effect…

Kantor, Shawn; Whalley, Alexander

2009-01-01

326

On the solution of the PBE with agglomeration and random growth rate dispersion  

Microsoft Academic Search

Solutions to the population balance equation, with the diffusivity term added, for a steady-state MSMPR crystallizer with agglomeration are presented. These solutions are obtained using two different sets of boundary conditions, and are examined in detail to obtain information on the initial conditions. Furthermore, we suggest conditions that may be helpful in discriminating and\\/or choosing suitable models.

Elias G. Saleeby; Hyun W. Lee

1995-01-01

327

Agglomeration due to Brownian motion of fractal-structured combustion aerosols  

SciTech Connect

A dynamic Monte-Carlo type lattice model has been developed to simulate the agglomeration of non-spherical chain-line aggregate combustion aerosols due to Brownian motion. Simulations are carried out in the free molecular and continuum regimes, for both initial monodisperse and initial log-normally distributed aerosols, with and without source mechanisms. Preservation of the chain-like structure of the aggregate is accomplished throughout the simulation by describing the agglomerate as fractal, that is, scale-invariant, self-similar with a noninteger dimensionality. Simulation results indicate that cluster growth is more rapid in the free molecular regime than in the continuum. Aerosols and log-normal distributions retain their log-normal characteristics even after long coagulation times. The effect of the clusters' fractal dimension on the cluster growth rate is determined; the rate of agglomeration increases when the structure of the agglomerate is more fragmented (lower fractal dimension). An analytical solution to the coagulation equation is obtained for log-normal aerosols by calculating moments of the distribution and solving sets of moment equations to determine the size distribution parameters. Condition numbers are employed to determine which moments should be calculated to most accurately determine these parameters. Excellent agreement is obtained between the simulations and the solution to the moment equations. Experimental measurements of soot particle velocity in a premixed methane/air flame are made using laser Doppler velocimetry.

Kaplan, C.H.

1987-01-01

328

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

NASA Astrophysics Data System (ADS)

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.

Bariš?, Vesna; Zabetta, Edgardo Coda; Sarkki, Juha

329

Quasiparticle agglomerates and environmental effects in the fractional quantum Hall edge states at ? = 5/2  

SciTech Connect

We discuss how the presence of environmental effects and quasiparticle agglomerates could better reconcile the edge states theories with the experimental observations for the case of ? = 5/2. The Pfaffian and the anti-Pfaffian models will be compared in connection with experimental results identifying the latter as the best candidate.

Braggio, A. [SPIN-CNR, Via Dodecaneso 33, 16146 Genova (Italy); Carrega, M. [NEST, Istituto Nanoscienze-CNR, and Scuola Normale Superiore, I-56126, Pisa (Italy); Ferraro, D.; Magnoli, N. [Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy and INFN, Via Dodecaneso 33, 16146, Genova (Italy); Sassetti, M. [Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy and SPIN-CNR, Via Dodecaneso 33, 16146 Genova (Italy)

2013-12-04

330

A scanning electron microscope study on agglomeration in petroleum coke-fired FBC boilers  

Microsoft Academic Search

Ten samples originating from different boiler FBC systems burning petroleum coke and one laboratory sample were chosen to perform a study on the development, structure, and composition of deposits formed by agglomeration in various locations. The work focused on examination by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. The possibility of a contribution of liquid phases in

J. V Iribarne; E. J Anthony; A Iribarne

2003-01-01

331

TECHNOLOGICAL AGGLOMERATION AND THE EMERGENCE OF CLUSTERS AND NETWORKS IN NANOTECHNOLOGY  

E-print Network

- 1 - TECHNOLOGICAL AGGLOMERATION AND THE EMERGENCE OF CLUSTERS AND NETWORKS IN NANOTECHNOLOGY clusters in nanotechnologies (MESA+ (Twente) and other centres in the Netherlands and Minatec in Grenoble nanotechnology-linked developments. We will use our ongoing studies of regions with a high concentration

Paris-Sud XI, Université de

332

Cluster or Capture? Manufacturing Foreign Direct Investment, External Economies and Agglomeration  

Microsoft Academic Search

Phelps N. A. Cluster or capture? Manufacturing foreign direct investment, external economies and agglomeration, Regional Studies.?This paper reviews the nature and significance of external economies associated with multinational enterprise (MNE) participation in the manufacturing industries of host economies. It argues that the balance of forces of internalization and externalization is currently skewed towards the former and the interests of MNEs

N. A. Phelps

2008-01-01

333

Development of Systematic Models for Aerosol Agglomeration and Spray Removal under Severe Accident Conditions  

Microsoft Academic Search

Radionuclide behavior during various severe accident conditions has been addressed as one of the important issues to discuss environmental safety in nuclear power plants. The present paper deals with the development of analytical models and their validations for the agglomeration of multiple-component aerosol and spray removal that controls source terms to the environment of both aerosols and gaseous radionuclides during

Mitsuhiro KAJIMOTO

2008-01-01

334

Development and application of a constant supersaturation, semi-batch crystalliser for investigating gibbsite agglomeration  

NASA Astrophysics Data System (ADS)

The development is described of a constant supersaturation crystalliser (CSC) designed primarily to investigate the size dependency of the agglomeration kernel for the commercially important, but difficult to study, gibbsite-caustic aluminate system. The capabilities of the CSC were illustrated by a series of experiments conducted at supersaturation ratios of 1.67 and 1.86, at 80°C. The results supported findings reported in the literature that the gibbsite agglomeration rate kernel is size independent at shear rates above 480 s -1 and has a strong inverse dependency on the mean shear rate. The results indicate that under these conditions the crystal collision processes are not rate determining for gibbsite agglomeration in turbulent stirred tanks. The agglomeration kernel was shown to be independent of the crystalliser's solids content. Other CSC results showed that gibbsite linear growth rates are: (1) independent of the average shear rates, which is consistent with the surface reaction controlled growth mechanism proposed in the literature, and (2) independent of crystal size (i.e. McCabe ? L law).

Ilievski, Dean

2001-12-01

335

Agglomeration of inertial particles in a random rotating symmetric straining flow  

Microsoft Academic Search

This paper is concerned with the development and validation of a simple Lagrangian model for particle agglomeration in a turbulent flow involving the collision of particles in a sequence of correlated straining and vortical structures which simulate the Kolmogorov small scales of motion of the turbulence responsible for particle pair dispersion and collision. In this particular study we consider the

Yasmine Ammar; Michael Reeks

2009-01-01

336

Iron Oxide Nanoparticle Agglomeration Influences Dose-Rates and Modulates Oxidative Stress Mediated Dose-Response Profiles In Vitro  

SciTech Connect

Spontaneous agglomeration of engineered nanoparticles (ENPs) is a common problem in cell culture media which can confound interpretation of in vitro nanotoxicity studies. The authors created stable agglomerates of iron oxide nanoparticles (IONPs) in conventional culture medium, which varied in hydrodynamic size (276 nm-1.5 ?m) but were composed of identical primary particles with similar surface potentials and protein coatings. Studies using C10 lung epithelial cells show that the dose rate effects of agglomeration can be substantial, varying by over an order of magnitude difference in cellular dose in some cases. Quantification by magnetic particle detection showed that small agglomerates of carboxylated IONPs induced greater cytotoxicity and redox-regulated gene expression when compared with large agglomerates on an equivalent total cellular IONP mass dose basis, whereas agglomerates of amine-modified IONPs failed to induce cytotoxicity or redox-regulated gene expression despite delivery of similar cellular doses. Dosimetry modelling and experimental measurements reveal that on a delivered surface area basis, large and small agglomerates of carboxylated IONPs have similar inherent potency for the generation of ROS, induction of stress-related genes and eventual cytotoxicity. The results suggest that reactive moieties on the agglomerate surface are more efficient in catalysing cellular ROS production than molecules buried within the agglomerate core. Because of the dynamic, size and density-dependent nature of ENP delivery to cells in vitro, the biological consequences of agglomeration are not discernible from static measures of exposure concentration (?g/ml) alone, highlighting the central importance of integrated physical characterisation and quantitative dosimetry for in vitro studies. The combined experimental and computational approach provides a quantitative framework for evaluating relationships between the biocompatibility of nanoparticles and their physical and chemical characteristics.

Sharma, Gaurav; Kodali, Vamsi K.; Gaffrey, Matthew J.; Wang, Wei; Minard, Kevin R.; Karin, Norman J.; Teeguarden, Justin G.; Thrall, Brian D.

2013-07-31

337

Agglomeration characteristics of silica sand-rice husk ash mixtures at elevated temperatures  

SciTech Connect

Rice husk, a major by-product of the rice milling process, can be a significant energy resource in rice producing countries because of its high energy content. Fluidized bed gasifiers have been proposed for the recovery of energy from rice husk. The major advantage of fluidized bed gasifiers over fixed bed gasifiers is the high mass and heat transfer capability due to very high percentage of inert bed material such as silica sand. In addition, the vigorous mixing and agitation of solid particles in fluidized beds promote a uniform temperature distribution and a high conversion efficiency. However, attempts to utilize rice husk as a feed in fluidized bed gasifiers have been unsuccessful because of the high ash content of rice husk that may result in the agglomeration of inert bed materials at high temperatures. In this work, the effect of rice husk ash content on the agglomeration characteristics of silica sand was investigated at various temperatures using a muffle furnace. A light microscope, an environmental scanning electron microscope, and an energy dispersive X-ray analyzer were used to characterize the structural changes and elemental makeup of the samples. There was no indication of agglomeration below 850 C, but at temperatures of 850--1,000 C the silica sand loosely agglomerated in the presence of rice husk ash at all levels of ash content. The effect was more pronounced at 1,000 C. The chemical interaction of the SiO{sub 2} and the low melting temperature mineral oxides present in notably low concentrations in rice husk ash, appeared to be the mechanism resulting in the formation of the loose agglomerates.

Mansaray, K.G.; Ghaly, A.E. [Technical Univ. of Nova Scotia, Halifax (Canada). Agricultural Engineering Dept.

1998-08-01

338

Pilot plant testing of IGT`s two-stage fluidized-bed/cyclonic agglomerating combustor  

SciTech Connect

The Institute of Gas Technology (IGT) is conducting a multi-year experimental program to develop and test, through pilot-scale operation, IGT`s two-stage fluidized-bed/cyclonic agglomerating combustor (AGGCOM). The AGGCOM process is based on combining the fluidized-bed agglomeration and gasification technology with the cyclonic combustion technology, both of which have been developed at IGT over many years. AGGCOM is a unique and extremely flexible combustor that can operate over a wide range of conditions in the fluidized-bed first stage from low temperature (desorption) to high temperature (agglomeration), including gasification of high-energy-content wastes. The ACCCOM combustor can easily and efficiently destroy solid, liquid, and gaseous organic wastes, while isolating solid inorganic contaminants within an essentially non-leachable glassy matrix, suitable for disposal in ordinary landfills. Fines elutriated from the first stage are captured by a high-efficiency cyclone and returned to the fluidized bed for ultimate incorporation into the agglomerates. Intense mixing in the second-stage cyclonic combustor ensures high destruction and removal efficiencies (DRE) for organic compounds that may be present in the feed material. This paper presents an overview of the experimental development of the AGGCOM process and progress made to date in designing, constructing, and operating the 6-ton/day AGGCOM pilot plant. Results of the bench-scale tests conducted to determine the operating conditions necessary to agglomerate a soil were presented at the 1991 Incineration Conference. On-site construction of the AGGCOM pilot plant was initiated in August 1992 and completed at the end of March 1993, with shakedown testing following immediately thereafter. The initial tests in the AGGCOM pilot plant will focus on the integrated operation of both stages of the combustor and will be conducted with ``clean`` topsoil.

Rehmat, A.; Mensinger, M.C. [Institute of Gas Technology, Chicago, IL (United States); Richardson, T.L. [Environmental Protection Agency, Cincinnati, OH (United States)

1993-12-31

339

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

PubMed

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. PMID:19775871

Tantra, Ratna; Tompkins, Jordan; Quincey, Paul

2010-01-01

340

Bed material agglomeration during fluidized bed combustion. Technical progress report, January 1, 1993--March 31, 1993  

SciTech Connect

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 and to relate these reactions to specific causes. A survey of agglomeration and deposit formation in industrial fluidized bed boilers is in progress. Preliminary results indicate that at least five boilers were experiencing some form of bed material agglomeration. In these instances it was observed that large particles were forming within the bed which were larger that the feed. Four operators could confirm that the larger bed particles had formed due to bed particles sticking together or agglomerating. Deposit formation was reported at nine sites with these deposits being found most commonly at coal feed locations and in cyclones. Other deposit locations included side walls and return loops. Examples of these agglomerates and deposits have been received from five of the surveyed facilities. Also during this quarter, a bulk sample of Illinois No. 6 coal was obtained from the Fossil Energy Program at Ames Laboratory here at Iowa State University and prepared for combustion tests. This sample was first ground to a top-size of 3/8`` using a jaw crusher then a size fraction of 3/8`` {times} 8 (US mesh) was then obtained by sieving using a Gilson Test-Master. This size fraction was selected for the preliminary laboratory-scale experiments designed to simulate the dense bed conditions that exist in the bottom of CFB combustors. To ensure uniformity of fuel composition among combustion runs, the sized coal was riffled using, a cone and long row method and stored in bags for each experiment. During this quarter additional modifications were made to achieve better control of fluidization regimes and to aid in monitoring the hydrodynamic and chemical conditions within the reactor.

Brown, R.C.; Dawson, M.R.; Noble, S.D.

1993-04-01

341

Development and Assessment of Oil-in-Water Emulsions for Encapsulation of Reactive Iron Particles for Subsurface Delivery  

NASA Astrophysics Data System (ADS)

Reactive iron particles hold promise for use in the destruction of contaminants in the subsurface environment. Application of these nano- to submicron-scale particles, however, may be limited by poor subsurface transport and non-uniform distribution of the reactive material. Delivery issues are particularly important when evaluating the efficacy of iron-based technologies for treatment of dense non-aqueous phase liquid (DNAPL) source zones. Current approaches for the delivery of reactive iron particles within DNAPL source zones are hindered by particle agglomeration, flow bypassing, and presence of non-target reactions. Encapsulation of the reactive particles within an oil-in-water emulsion is a novel approach that may overcome these limitations. Development of kinetically-stable, iron-laden, oil-in-water emulsions commenced by identifying surfactant-based coatings to increase the stability of commercially-available iron particles within non-polar organic phases (e.g., soy oil). A phase inversion technique was employed to disperse approximately 10% wt of the iron-laden, organic phase within a continuous aqueous phase containing nonionic emulsifiers. Emulsions were designed to ensure emulsifier proportions yielded hydrophilic-lipophilic balances affiliated with oil-in-water emulsions. Micrographs of the oil-in-water emulsions suggest that the average diameter of the oil droplets is approximately one micrometer. The presence of iron within oil droplets was confirmed in the micrographs and supported by an absence of iron agglomeration within the continuous phase. Bulk characteristics of each emulsion (density and viscosity) were used in conjunction with interfacial tension measurements in total trapping number analyses to assess the propensity of these emulsions to mobilize an entrapped trichloroethene (TCE)-DNAPL. Results suggest that the emulsions described herein should not cause significant mobilization of entrapped TCE-DNAPL in fine-to-medium grain sandy media. Column experiments are being conducted to evaluate the transport of these emulsions through sandy media. Preliminary results from experiments with iron-free emulsions suggest conductivity reductions occurring during emulsion flushing are not the result of extensive pore-clogging but rather are due to viscosity changes (emulsion viscosities range from 2 to 10 cP). Current efforts are focused on assessing and comparing both transport and reaction of commercially available iron particles and iron-laden emulsions within sandy porous media.

Berge, N. D.; Taghavy, A.; Ramsburg, A.

2007-12-01

342

Shale oil cracking. 2. Effect on oil composition  

Microsoft Academic Search

Results from spectroscopic investigations are presented that demonstrate the effect of oil cracking on shale oil composition. Techniques used include infrared spectroscopy, capillary column gas chromatography\\/mass spectroscopy and ¹³C nuclear magnetic resonance. We show that cracking causes an increase in aromatic and alkene content of the oil. We compare our results for oils prepared in the laboratory with oils prepared

A. K. Burnham; R. H. Sanborn; R. W. Crawford; J. C. Newton; J. A. Happe

1980-01-01

343

The measurement of mixture homogeneity and dissolution to predict the degree of drug agglomerate breakdown achieved through powder mixing.  

PubMed

Interactive mixing of agglomerates of small, cohesive particles with coarse carrier particles facilitate the deaggregation of agglomerates. In this study dispersion of agglomerates of microfine furosemide particles by such a mixing process was followed by measuring changes in the content uniformity and area under the dissolution curve. Interactive mixtures between agglomerates of different sized furosemide particles and coarse sodium chloride particles were prepared using different mixers, mixing times and mixer speeds. The dissolution rate of the drug from and content uniformity of the mixtures were measured, and degrees of dispersion were calculated. These degrees of dispersion were compared to the dispersion values obtained from the decrease in agglomerate size after mixing. An increase in mixing time led to an increase in dispersion. An initial fast deagglomeration, indicated by an increase in dissolution, increase in content uniformity and a decrease in particle size, was followed by substantially slower deaggregation of remaining agglomerates and smaller aggregates. For all mixtures studied the degree of dispersion estimated from dissolution measurements, when compared to equivalent content uniformity measurements, agreed closely with the degree of dispersion as indicated by the decrease in particle size. The use of the area under the dissolution curve to predict agglomerate breakdown proved useful and may find application in situations where it is impossible to follow directly deagglomeration through particle size measurements. PMID:7870671

de Villiers, M M; Van der Watt, J G

1994-11-01

344

A study of the evolution of the physicochemical and structural characteristics of olive and sunflower oils after heating at frying temperatures  

Microsoft Academic Search

The evolution of the density, viscosity, oil\\/water interfacial tension and structure of vegetable oils after heating at frying temperatures was studied to explore the possibility of reusing waste vegetable oils as solid agglomerants for different purposes. Commercial olive and sunflower oils were heated at 150 and 225°C in the time interval of 1–15 days to achieve a wide range of

Adolfo F. Valdés; Ana B. Garcia

2006-01-01

345

Studies of the morphology and dynamics of flame-generated agglomerates using dynamic light scattering  

NASA Astrophysics Data System (ADS)

Accurate determination of the morphology and dynamics of aerosols consisting of agglomerated sub-micron sized particulates is needed for soot formation studies, process monitoring in flame-based materials synthesis applications, and pollution control studies. The objective of the current study is to investigate the application of dynamic light scattering (DLS) to flames as an extension of current measurement technologies. Unlike previous DLS flame studies, conventional polarized DLS is supplemented with depolarized DLS measurements to account for the agglomerates' anisotropy. Because unavailable relationships between the agglomerates' morphological parameters and the Brownian translational and rotational diffusion coefficients under non-continuum conditions are required for accurately determining agglomerate morphology from DLS flame measurements, the potential of combining DLS-determined diffusion coefficients with independently-determined morphology measurements to provide the necessary experimental relationships is investigated. For this study DLS measurements and thermophoretic agglomerate sampling were performed on chainlike iron oxide agglomerates occurring within a 1/2/prime' diameter Fe(CO)5-seeded CO/O2 diffusion flame. Systematic detection system errors in the DLS measurements, caused by dead time and afterpulsing, were virtually eliminated by cross- correlating the outputs of two separate photomultiplier tubes. The accompanying decrease in the signal-to-noise ratio was compensated by increasing the incident laser power and experiment duration time. This duration time increase was accomplished by combining the data from multiple five-minute experiments because of severe iron oxide deposition on the burner and flame stabilizer occurring with longtime, continuous flame operation. Accurate depolarized DLS data was thus generated from a flame environment for the first time. Inverse Laplace transform analyses of the DLS data using CONTIN produced unacceptable fits of the data. Cumulants fits were more accurate but systematically produced negative second cumulant coefficients, which prevent a complete linewidth distribution analysis and indicate the presence of invalid assumptions used in the conventional theoretical DLS interpretations. Additional experiments implicated incident beam nonuniformities as a partial cause of this effect. Average diffusion coefficients extracted from the first cumulants exhibited an order-of- magnitude agreement with theoretical estimates based on ex situ morphology and flame temperature measurements.

Waguespack, Glenn Michael

1997-12-01

346

Survey and evaluation of instream habitat and stock restoration techniques for wild pink and chum salmon. Restoration study number 105-1 (restoration project 93063). Exxon Valdez oil spill state/federal natural resource damage assessment final report  

SciTech Connect

This project is the result of a three-year survey of the Exxon Valdez oil spill impact area to identify appropriate and cost-effective instream habitat restoration techniques for salmon, including spawning channels and improvement of fish passage through fish ladders or step-pool structures to overcome physical or hydrological barriers. Additional wild salmon stock rehabilitation measures include stream-side incubation boxes, remote egg-taking, incubation at existing hatcheries for fry stocking in oil-impacted streams, and fry rearing. Study results include the identification of the most promising instream habitat restoration projects in each of the spill-impacted areas.

Willette, T.M.; Dudiak, N.C.; Honnold, S.G.; Carpenter, G.; Dickson, M.

1995-08-01

347

Oil Oil Everywhere  

NSDL National Science Digital Library

This math meets ecology lesson provides hands-on experiences with mixing oil and water, provides surface area information about the 2010 oil spill in the Gulf of Mexico, and gives learners opportunities to estimate small oil spills of their own making. This lesson guide includes questions for learners, assessment options, extensions, and reflection questions.

Cartwright, Lisa

2010-01-01

348

BP Oil Spill November 10, 2011  

E-print Network

BP Oil Spill Qiyam Tung November 10, 2011 1 Introduction Figure 1: BP Oil spill (source: http://thefoxisblack.com/2010/05/02/the-bp-oil-spill-in-the-gulf-of-mexico/) Last year, there was a major oil spill caused major techniques to minimize the threat once it happened. What kind of damage would an oil spill like this cause

Lega, Joceline

349

Formulation techniques for nanofluids.  

PubMed

Fluids with suspended nanoparticles, commonly known as nanofluids, may be formulated to improve the thermal performance of industrial heat transfer systems and applications. Nanofluids may show enhanced thermal and electrical properties such as thermal conductivity, viscosity, heat transfer coefficient, dielectric strength, etc. However, stability problems may arise as nanoparticles usually have the tendency to agglomerate and sediment producing deterioration in the increment of these properties. In this review, we discuss patents that report advances in the formulation of nanofluids including: production methods, selection of components (nanoparticles, base fluid and surfactants), their chemical compositions and morphologies, and characterization techniques. Finally, current and future directions in the development of nanofluid formulation are discussed. PMID:24330043

Rivera-Solorio, Carlos I; Payán-Rodríguez, Luis A; García-Cuéllar, Alejandro J; Ramón-Raygoza, E D; L Cadena-de-la-Peña, Natalia; Medina-Carreón, David

2013-11-01

350

Green surfactant for enhanced oil recovery  

Microsoft Academic Search

Chemical enhanced oil recovery methods are field proven techniques that improve efficiency and effectiveness of oil recovery. High oil prices and dropping reserves alternative has inspired interest in chemical flooding technologies, particularly for application in mature water flooding. The more concern about this technique is surfactant development. A new sulfonate surfactant from non-edible vegetable oils is developed as an alternative

Saeed Majidaie; Mushtaq Muhammad; Isa M. Tan; Birol Demiral

2011-01-01

351

Transfer-free graphene synthesis on insulating substrates via agglomeration phenomena of catalytic nickel films  

NASA Astrophysics Data System (ADS)

Graphene layers were synthesized by annealing amorphous carbon (a-C) thin films on Ni/SiO2/Si(111) substrates grown using pulse arc plasma deposition. Although the graphene layers were formed by catalytic reaction between a-C films and Ni metals, they were observed to be directly on the insulating SiO2/Si substrates with island-shaped metallic particles. These particles presumably resulted from agglomeration phenomena of thin Ni films at a high temperature. We speculated that the agglomeration phenomena allowed the graphene formation on SiO2/Si substrates. It was also confirmed that the particle size and graphene layer thickness depend on the starting Ni thickness.

Banno, Kazuya; Mizuno, Masaya; Fujita, Kazuhisa; Kubo, Toshiharu; Miyoshi, Makoto; Egawa, Takashi; Soga, Tetsuo

2013-08-01

352

Recent satellite-based trends of tropospheric nitrogen dioxide over large urban agglomerations worldwide  

NASA Astrophysics Data System (ADS)

Trends in tropospheric nitrogen dioxide (NO2) concentrations over 66 large urban agglomerations worldwide have been computed using data from the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) instrument onboard the Envisat platform for the period August 2002 to March 2012. A seasonal model including a linear trend was fitted to the satellite-based time series over each site. The results indicate distinct spatial patterns in trends. While agglomerations in Europe, North America, and some locations in East Asia/Oceania show decreasing tropospheric NO2 levels on the order of -5 % yr-1, rapidly increasing levels of tropospheric NO2 are found for agglomerations in large parts of Asia, Africa, and South America. The site with the most rapidly increasing absolute levels of tropospheric NO2 was found to be Tianjin in China with a trend value of 3.04 (±0.47) × 1015 molecules cm-2 yr-1, whereas the site with the most rapidly increasing relative trend was Kabul in Afghanistan with 14.3 (±2.2) % yr-1. In total, 34 sites exhibited increasing trends of tropospheric NO2 throughout the study period, 24 of which were found to be statistically significant. A total of 32 sites showed decreasing levels of tropospheric NO2 during the study period, of which 20 sites did so at statistically significant magnitudes. Overall, going beyond the relatively small set of megacities investigated previously, this study provides the first consistent analysis of recent changes in tropospheric NO2 levels over most large urban agglomerations worldwide.

Schneider, P.; Lahoz, W. A.; van der A, R.

2014-09-01

353

Three-dimensional simulation of thermal plasma spraying of partially molten ceramic agglomerates  

Microsoft Academic Search

Thermal plasma spraying of agglomerated nanostructured ceramic particles has been studied using computational fluid dynamics.\\u000a The plasma jet is modeled as a mixture of Ar-H2 plasmas issuing into a quiescent atmosphere. The particles, modeled as micron-sized spheres, are introduced into the jet\\u000a outside the plasma gun exit with radial injection. The existence of a simple target in front of the

I. Ahmed; T. L. Bergman

2000-01-01

354

Size control and characterization of Au nanoparticle agglomeration during encapsulation in sol–gel matrices  

Microsoft Academic Search

Gold nanoparticles were encapsulated in sol–gel matrices with different amine cross-linker molecules in order to determine the cross-linker influence on nanoparticle agglomeration behaviour during encapsulation. The role of a stabilizing surfactant (SDS) was also investigated. The NP aggregate sizes were tracked using the UV surface plasmon resonance band (SPR), which red-shifts with increased particle size. It was found that use

Adam C. Malcolm; J. Mark Parnis; Andrew J. Vreugdenhil

2011-01-01

355

Aerosol influence domain of Beijing and peripheral city agglomeration and its climatic effect  

Microsoft Academic Search

The aerosol distribution in Beijing and peripheral cities agglomeration (BPCA) and its regional climatic effect are investigated\\u000a on the basis of the statistical analyses of satellite Total Ozone Mapping Spectrometer (TOMS) retrieval aerosol optical depth\\u000a (AOD) and the meteorological data of sunshine duration, fog days, and low cloud cover, observed at Beijing and its peripheral\\u000a meteorological stations. The analysis on

Xiangde Xu; Xiaohui Shi; Shengjun Zhang; Guoan Ding; Qiuju Miao; Li Zhou

2006-01-01

356

Antisolvent-induced agglomeration of mineral matter in coal-derived liquids. Final report  

Microsoft Academic Search

The influence of many of the variables associated with anti-solvent induced agglomeration of mineral matter in coal derived liquids was observed by an indirect x-ray photographic measurement of sedimentation. The primary variables were anti-solvent type, dose, combinations of anti-solvent and gas, anti-solvent addition rate, and mixing properties. Also, the properties of the coal derived liquids have a great influence on

J. D. Jr. Henry; F. H. Verhoff

1981-01-01

357

Development and application of a constant supersaturation, semi-batch crystalliser for investigating gibbsite agglomeration  

Microsoft Academic Search

The development is described of a constant supersaturation crystalliser (CSC) designed primarily to investigate the size dependency of the agglomeration kernel for the commercially important, but difficult to study, gibbsite–caustic aluminate system. The capabilities of the CSC were illustrated by a series of experiments conducted at supersaturation ratios of 1.67 and 1.86, at 80°C. The results supported findings reported in

Dean Ilievski

2001-01-01

358

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

SciTech Connect

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)

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

1990-04-01

359

The effect of wetting liquid droplet size on the growth of agglomerates during wet drum granulation  

Microsoft Academic Search

Results of investigation of the effect of wetting liquid droplet size on the growth of agglomerates during wet drum granulation of dolomite flour of selected grain-size composition which guaranteed geometrical similarity were discussed.The process of granulation was carried out batch-wise in a drum granulator 0.5 m in diameter and 0.4 m long at rotational speed 0.33 s?1 and constant volumetric

Tadeusz Gluba

2003-01-01

360

Sonic Enhanced Ash Agglomeration and Sulfur Capture. Technical progress report, April--June 1993  

SciTech Connect

The shakedown testing of the system proceeded on schedule. Some of the preliminary results were ambiguous in that they indicated a higher carbon concentration in the baghouse than in the cyclone. Apparently this was due to the use of the baghouse for tests on an integrated coal-fired boiler. This was remedied by installing a separate baghouse for the bimodal agglomeration testing. The testing with coal/dolomite mixture indicated that the sulfur is captured effectively with the present system configuration and that combustion efficiencies were greater than 99 percent. The coal/dolomite test was on-line for approximately 7 hours during which it achieved steady-state operation at 3 atmospheres for about 5 1/2 hours. The agglomeration chamber catch contained agglomerates ranging in size from 1/4 to 3/4 inches. West Virginia University developed some new aerovalve designs including a vortex design for the vitiated air pulse combustor. A set of modifications resulting from the initial shakedown tests were also completed.

Not Available

1993-12-31

361

Benign reduction of carbon nanotube agglomerates using a supercritical carbon dioxide process  

NASA Astrophysics Data System (ADS)

A method was developed to deagglomerate commercially available multi-walled carbon nanotube (MWCNT) bundles while maintaining the carbon nanotube aspect ratio. The process utilizes the rapid expansion of a supercritical carbon dioxide/MWCNT mixture to separate large primary carbon nanotube agglomerates. High levels of deagglomeration of Baytubes® C 150 P and Nanocyl™ NC-7000 MWCNT bundles were observed on the macroscale and nanoscale, resulting in 30-fold and 50-fold decreases in bulk density, respectively, with median agglomerate sizes <8 ?m in diameter. These results were obtained while retaining the aspect ratio of the as-received nanomaterial, irrespective of the MWCNT agglomerate morphology. It was found that a temperature and pressure of 40 °C and 7.86 MP resulted in maximum deagglomeration without damage to the MWCNTs. Thermodynamic principles were applied to describe the effect of processing variables on the efficiency of the deagglomeration. These results suggest that combining this process with a composite processing step, such as melt compounding, will result in nanocomposites with enhanced electrical properties.

Quigley, John P.; Herrington, Kevin; Bortner, Michael; Baird, Donald G.

2014-09-01

362

The impact of solution agglomeration on the deposition of self-assembled monolayers  

SciTech Connect

Self-assembled monolayers (SAMS) are commonly produced by immersing substrates in organic solutions containing trichlorosilane coupling agents. Unfortunately, such deposition solutions can also form alternate structures including inverse micelles and lamellar phases. The formation of alternate phases is one reason for the sensitivity of SAM depositions to factors such as the water content of the deposition solvent. If such phases are present, the performance of thin films used for applications such as minimization of friction and stiction in micromachines can be seriously compromised. Inverse micelle formation has been studied in detail for depositions involve 1H-, 1H-, 2H-, 2H-perfluorodecyltrichlorosilane (FDTS) in isooctane. Nuclear magnetic resonance experiments have been used to monitor the kinetics of hydrolysis and condensation reactions between water and FDTS. Light scattering experiments show that when hydrolyzed FDTS concentrations reach a critical concentration, there is a burst of nucleation to form high concentrations of spherical agglomerates. Atomic force microscopy results show that the agglomerates then deposit on substrate surfaces. Deposition conditions leading to monolayer formation involve using deposition times that are short relative to the induction time for agglomeration. After deposition, inverse micelles can be converted into lamellar or monolayer structures with appropriate heat treatments if surface concentrations are relatively low.

BUNKER,BRUCE C.; CARPICK,ROBERT W.; ASSINK,ROGER A.; THOMAS,MICHAEL L.; HANKINS,MATTHEW G.; VOIGT,JAMES A.; SIPOLA,DIANA L.; DE BOER,MAARTEN P.; GULLEY,GERALD L.

2000-04-17

363

Investigations on Agglomeration and Haemocompatibility of Vitamin E TPGS Surface Modified Berberine Chloride Nanoparticles  

PubMed Central

The objective of the present study is to investigate the influence of surface modification on systemic stability of NPs. Vitamin E TPGS (1% w/v) was used for surface modification of berberine chloride nanoparticles. Naked and surface modified NPs were incubated in different SBFs (pH 6.8 and 7.4) with or without bile salts and human plasma. NPs were observed for particle agglomeration and morphology by particle size analyzer and TEM, respectively. The haemocompatibility studies were conducted on developed NPs to evaluate their safety profile. The surface modified NPs were stable compared to naked NPs in different SBFs due to the steric stabilization property of vitamin E TPGS. Particle agglomeration was not seen when NPs were incubated in SBF (pH 6.8) with bile salts. No agglomeration was observed in NPs after their incubation in plasma but particle size of the naked NPs increased due to adhesion of plasma proteins. The TEM images confirmed the particle size results. DSC and FT-IR studies confirmed the coexistence of TPGS in surface modified NPs. The permissible haemolysis, LDH release, and platelet aggregation revealed that NPs were compatible for systemic administration. Thus, the study illustrated that the surface modification is helpful in the maintenance of stability of NPs in systemic conditions. PMID:25162037

Vuddanda, Parameswara Rao; Rajamanickam, Vijayakumar Mahalingam; Yaspal, Madhu; Singh, Sanjay

2014-01-01

364

Interpretation of gas liquid reactive crystallization data using a size-independent agglomeration model  

NASA Astrophysics Data System (ADS)

A CO 2-BaCl 2-H 2O gas-liquid reactive crystallization system, depicted by a size-independent agglomeration model, was successfully used to explore the crystallization kinetics of barium carbonate crystals. The growth kinetics shows that growth rate is proportional to a 1.85 order of relative supersaturation and decreases with an increase in pH value. The agglomeration kernel is nearly proportional to the growth rate of barium carbonate crystals and decreases with an increase in pH value. The nucleation rate of barium carbonate crystals is proportional to a 2.15 order of relative supersaturation revealing a heterogeneous nucleation mechanism. The size-independent agglomeration model is useful in the prediction of the elapsed time vs. the number of particles. The model shows that the precipitation occurs in showers within a period of a few minutes. Using the kinetic expressions obtained in this study, a comparison between calculated and measured numbers of particles is also discussed.

Chen, Pao-Chi; Liu, S. M.; Jang, C. J.; Hwang, R. C.; Yang, Y. L.; Lee, J. S.; Jang, J. S.

2003-10-01

365

Integrated low emission cleanup system for direct coal-fueled turbines (electrostatic agglomeration)  

SciTech Connect

The objective of this contract was to investigate the removal of SO[sub x] and particulate matter from direct coal fired combustion gas streams at high temperature and high pressure conditions. This investigation was to be accomplished through a bench scale testing and evaluation program for SO[sub x] removal and the innovative particulate collection concept of particulate growth through electrostatic agglomeration followed by high efficiency mechanical collection. The process goal was to achieve control better than that required by 1979 New Source Performance Standards. During Phase I, the designs of the combustor and gas cleanup apparatus were successfully completed. Hot gas cleanup was designed to be accomplished at temperature levels between 1800[degrees] and 2500[degrees]F at pressures up to 15 atmospheres. The combustor gas flow rate could be varied between 0.2--0.5 pounds per second. The electrostatic agglomerator residence time could be varied between 0.25 to 3 seconds. In Phase II, all components were fabricated, and erected successfully. Test data from shakedown testing was obtained. Unpredictable difficulties in pilot plant erection and shakedown consumed more budget resources than was estimated and as a consequence DOE, METC, decided ft was best to complete the contract at the end of Phase II. Parameters studied in shakedown testing revealed that high-temperature high pressure electrostatics offers an alternative to barrier filtration in hot gas cleanup but more research is needed in successful system integration between the combustor and electrostatic agglomerator.

Quimby, J.M.; Kumar, K.S.

1992-01-01

366

Solvent free microwave extraction of Elletaria cardamomum L.: A multivariate study of a new technique for the extraction of essential oil  

Microsoft Academic Search

The solvent-free microwave extraction (SFME) of cardamom essential oil (Elletaria cardamomum L.) was studied. A multivariate study based on a central composite design (CCD) was used to evaluate the influence of three major variables affecting the performance of the solvent-free microwave extraction of cardamom seed. The yield and the composition of the essential oils from the dry cardamom seeds obtained

Marie E. Lucchesi; Jacqueline Smadja; Steven Bradshaw; Willem Louw; Farid Chemat

2007-01-01

367

Oil-spill removal techniques and equipment. January 1980-October 1991 (Citations from the NTIS Data-Base). Rept. for Jan 80-Oct 91  

SciTech Connect

The bibliography contains citations concerning methods and equipment used for the containment and removal of oil as a result of oil spill mishaps. Dispersants, separators, skimmers and absorbents are discussed. Related studies regarding film spreading and dispersion are presented. (Contains 107 citations with title list and subject index).

Not Available

1991-09-01

368

Use of remote sensing techniques and aeromagnetic data to study episodic oil seep discharges along the Gulf of Suez in Egypt.  

PubMed

Four successive oil discharges were observed during the last 2 years following the recording of the earthquake events. Oil slicks were clearly observed in the thermal band of the Enhanced Thematic Mapper images acquired during the discharge events. Lineaments were extracted from the ETM+ image data and SRTM (DEM). The seismic activity is conformable in time and spatially related to active major faults and structural lineaments. The concerned site was subjected to a numerous earthquakes with magnitudes ranging from 3 to 5.4 Mb. Aeromagnetic field data analyses indicated the existence of deep major faults crossing the Gebel El-Zeit and the Mellaha basins (oil reservoirs). The magnetic field survey showed major distinctive fault striking NE-SW at 7000 m depth. Occurrence of these faults at great depth enables the crude oil to migrate upward and appear at the surfaces as oil seeps onshore and as offshore slicks in the Gemsa-Hurghada coastal zone. PMID:23688834

Kaiser, M F; Aziz, A M; Ghieth, B M

2013-07-15

369

Oil pollution signatures by remote sensing.  

NASA Technical Reports Server (NTRS)

Study of the possibility of developing an effective remote sensing system for oil pollution monitoring which would be capable of detecting oil films on water, mapping the areal extent of oil slicks, measuring slick thickness, and identifying the oil types. In the spectral regions considered (ultraviolet, visible, infrared, microwave, and radar), the signatures were sufficiently unique when compared to the background so that it was possible to detect and map oil slicks. Both microwave and radar techniques are capable of operating in adverse weather. Fluorescence techniques show promise in identifying oil types. A multispectral system will be required to detect oil, map its distribution, estimate film thickness, and characterize the oil pollutant.

Catoe, C. E.; Mclean, J. T.

1972-01-01

370

Agglomerated oral dosage forms of artemisinin/?-cyclodextrin spray-dried primary microparticles showing increased dissolution rate and bioavailability.  

PubMed

Artemisinin, a poorly water-soluble antimalarial drug, presents a low and erratic bioavailability upon oral administration. The aim of this work was to study an agglomerated powder dosage form for oral administration of artemisinin based on the artemisinin/?-cyclodextrin primary microparticles. These primary microparticles were prepared by spray-drying a water-methanol solution of artemisinin/?-cyclodextrin. ?-Cyclodextrin in spray-dried microparticles increased artemisinin water apparent solubility approximately sixfold. The thermal analysis evidenced a reduction in the enthalpy value associated with drug melting, due to the decrease in drug crystallinity. The latter was also evidenced by powder X-ray diffraction analysis, while (13)C-NMR analysis indicated the partial complexation with ?-cyclodextrin. Agglomerates obtained by sieve vibration of spray-dried artemisinin/?-cyclodextrin primary microparticles exhibited free flowing and close packing properties compared with the non-flowing microparticulate powder. The in vitro dissolution rate determination of artemisinin from the agglomerates showed that in 10 min about 70% of drug was released from the agglomerates, whereas less than 10% of artemisinin was dissolved from raw material powder. Oral administration of agglomerates in rats yielded higher artemisinin plasma levels compared to those of pure drug. In the case of the agglomerated powder, a 3.2-fold increase in drug fraction absorbed was obtained. PMID:23703233

Balducci, Anna Giulia; Magosso, Enrico; Colombo, Gaia; Sonvico, Fabio; Khan, Nurzalina Abdul Karim; Yuen, Kah Hay; Bettini, Ruggero; Colombo, Paolo; Rossi, Alessandra

2013-09-01

371

Oil Oil Everywhere  

NSDL National Science Digital Library

This lesson plan makes real world connections as students explore the ability to estimate the surface area of an oil spill. The lesson provides surface area information about the 2010 oil spill in the Gulf of Mexico, and gives students opportunities to estimate small oil spills of their own making. This lesson includes two students activity sheets, one fractional amount overhead sheet, assessment and extension suggestions, and questions for reflection.

Cartwright, Lisa

2010-01-01

372

Oil spill identification  

Microsoft Academic Search

To unambiguously identify spilled oils and petroleum products and to link them to the known sources are extremely important in settling questions of environmental impact and legal liability. This article briefly reviews the most recent development and advances of chemical fingerprinting and data interpretation techniques which are most frequently used in oil spill identification studies, including recognition of relative distribution

Zhendi Wang; Merv Fingas; David S Page

1999-01-01

373

The Preparation and Characterization of Poly(lactide-co-glycolide) Microparticles. II. The Entrapment of a Model Protein Using a (Water-in-Oil)inWater Emulsion Solvent Evaporation Technique  

Microsoft Academic Search

Poly(lactide-co-glycolide) (PLG) microparticles with entrapped antigens have recently been investigated as controlled-release vaccines. This paper describes the preparation of PLG microparticles with an entrapped model antigen, ovalbumin (OVA), using a (water-in-oil)-in-water emulsion solvent evaporation technique. In a series of experiments, the effects of process parameters on particle size and OVA entrapment were investigated. It was found that smooth, spherical microparticles

Hayley Jeffery; Stanley S. Davis; Derek T. O'Hagan

1993-01-01

374

Techniques for mapping the types, volumes, and distribution of clays in petroleum reservoirs and for determining their effects on oil production  

SciTech Connect

This report presents the results of correlation of log signatures with information on distribution of the types and volumes of clays in sandstone pore spaces determined from detailed CT-scan, XRD, SEM, and thin section analyses of core samples from three sandstone reservoirs. The log signatures are then analyzed to determine if suitable mathematical/statistical parameter(s) could be calculated from the logs to determine their effects on permeability and oil production. The variability measures obtained from power spectral analysis of permeability and wireline log data in clayey formations have been correlated with oil production from two oil fields. Compared with the conventional measures of permeability variations like the Dykstra-Parsons coefficients, the new measure appears to correlate better with oil production.

Sharma, B.

1993-05-01

375

Techniques for mapping the types, volumes, and distribution of clays in petroleum reservoirs and for determining their effects on oil production. Final report  

SciTech Connect

This report presents the results of correlation of log signatures with information on distribution of the types and volumes of clays in sandstone pore spaces determined from detailed CT-scan, XRD, SEM, and thin section analyses of core samples from three sandstone reservoirs. The log signatures are then analyzed to determine if suitable mathematical/statistical parameter(s) could be calculated from the logs to determine their effects on permeability and oil production. The variability measures obtained from power spectral analysis of permeability and wireline log data in clayey formations have been correlated with oil production from two oil fields. Compared with the conventional measures of permeability variations like the Dykstra-Parsons coefficients, the new measure appears to correlate better with oil production.

Sharma, B.

1993-05-01

376

HETEROGENEOUS SHALLOW-SHELF CARBONATE BUILDUPS IN THE PARADOX BASIN, UTAH AND COLORADO: TARGETS FOR INCREASED OIL PRODUCTION AND RESERVES USING HORIZONTAL DRILLING TECHNIQUES  

Microsoft Academic Search

The Paradox Basin of Utah, Colorado, Arizona, and New Mexico contains nearly 100 small oil fields producing from carbonate buildups within the Pennsylvanian (Desmoinesian) Paradox Formation. These fields typically have one to 10 wells with primary production ranging from 700,000 to 2,000,000 barrels (111,300-318,000 m³) of oil per field and a 15 to 20 percent recovery rate. At least 200

David E. Eby; Jr. Thomas C. Chidsey; Kevin McClure; Craig D. Morgan

2003-01-01

377

Dust agglomeration  

NASA Technical Reports Server (NTRS)

John Marshall, an investigator at Ames Research Center and a principal investigator in the microgravity fluid physics program, is studying the adhesion and cohesion of particles in order to shed light on how granular systems behave. These systems include everything from giant dust clouds that form planets to tiny compressed pellets, such as the ones you swallow as tablets. This knowledge should help us control the grains, dust, and powders that we encounter or use on a daily basis. Marshall investigated electrostatic charge in microgravity on the first and second U.S. Microgravity Laboratory shuttle missions to see how grains aggregate, or stick together. With gravity's effects eliminated on orbit, Marshall found that the grains of sand that behaved ever so freely on Earth now behaved like flour. They would just glom together in clumps and were quite difficult to disperse. That led to an understanding of the prevalence of the electrostatic forces. The granules wanted to aggregate as little chains, like little hairs, and stack end to end. Some of the chains had 20 or 30 grains. This phenomenon indicated that another force, what Marshall believes to be an electrostatic dipole, was at work.(The diagram on the right emphasizes the aggregating particles in the photo on the left, taken during the USML-2 mission in 1995.)

2000-01-01

378

Chromatographic techniques for the determination of alkyl-phenols, tocopherols and other minor polar compounds in raw and roasted cold pressed cashew nut oils.  

PubMed

Anacardium occidentale belongs to the family Anacardiaceae and is principally grown in tropical America (Mexico, Peru, Brazil, etc.) and India. Cashew nuts contain low amounts of hydroxy alkyl phenols that come from an oily liquid present in their shell and that is known as cashew-nut shell liquid. This paper reports the alkyl phenols composition of cold pressed raw and roasted cashew nut oil. First of all, cashew nut shell liquid was used for a basic fractionation of the alkyl phenol classes by preparative TLC and definitively identified by GC-MS and GC-FID. Anacardic acids were the major alkylphenols contained in both oils followed by cardol, cardanol and 2-methylcardol compounds, respectively. Raw and roasted oils did not show different compositions except for cardanols. The oil produced from roasted cashew nut reported a higher concentration of cardanols. Furthermore, tocopherols and other minor polar compounds were determined by HPLC-FLD and HPLC-DAD-MS, respectively. Tocopherol content varied in a range of 171.48-29.56mg/100g from raw to roasted cashew nut oil, being ?-tocopherol the one which presented a higher decrease (93.68%). Also minor polar compounds in cashew oil decreased after roasting from 346.52 to 262.83mg/kg. PMID:20961547

Gómez-Caravaca, Ana María; Verardo, Vito; Caboni, Maria Fiorenza

2010-11-19

379

Wear Metal Analysis of Oils  

Microsoft Academic Search

This article concentrates on reviewing the literature related with wear metal analysis of oils. An overview on the existence of metals in oils and typical wearing situations is discussed briefly. Different pre-treatment methods of oil samples before wear metal analysis are presented with application remarks. Common measurement techniques of wear metal analysis, both qualitative and quantitative, are handled and compared

Pekka Vähäoja; Ilkka Välimäki; Katri Roppola; Toivo Kuokkanen; Sulo Lahdelma

2008-01-01

380

Population amalgamation and genetic variation: observations on artificially agglomerated tribal populations of Central and South America.  

PubMed

The interpretation of data on genetic variation with regard to the relative roles of different evolutionary factors that produce and maintain genetic variation depends critically on our assumptions concerning effective population size and the level of migration between neighboring populations. In humans, recent population growth and movements of specific ethnic groups across wide geographic areas mean that any theory based on assumptions of constant population size and absence of substructure is generally untenable. We examine the effects of population subdivision on the pattern of protein genetic variation in a total sample drawn from an artificial agglomerate of 12 tribal populations of Central and South America, analyzing the pooled sample as though it were a single population. Several striking findings emerge. (1) Mean heterozygosity is not sensitive to agglomeration, but the number of different alleles (allele count) is inflated, relative to neutral mutation/drift/equilibrium expectation. (2) The inflation is most serious for rare alleles, especially those which originally occurred as tribally restricted "private" polymorphisms. (3) The degree of inflation is an increasing function of both the number of populations encompassed by the sample and of the genetic divergence among them. (4) Treating an agglomerated population as though it were a panmictic unit of long standing can lead to serious biases in estimates of mutation rates, selection pressures, and effective population sizes. Current DNA studies indicate the presence of numerous genetic variants in human populations. The findings and conclusions of this paper are all fully applicable to the study of genetic variation at the DNA level as well. PMID:3189334

Chakraborty, R; Smouse, P E; Neel, J V

1988-11-01

381

Reverse micelle synthesis of oxide nanopowders: mechanisms of precipitate formation and agglomeration effects.  

PubMed

We present an analysis of reverse micelle stability in four model systems. The first two systems, composed of unstable microemulsions of isooctane, water, and Na-AOT with additions of either iron sulfate or yttrium nitrate, were used for the synthesis of iron oxide or yttrium oxide powders. These oxide powders were of nanocrystalline character, but with some level of agglomeration that was dependent on calcination temperature and cleaning procedures. Results show that even though the reverse micellar solutions were unstable, nanocrystalline powders with very low levels of agglomeration could be obtained. This effect can be attributed to the protective action of the surfactant on the surfaces of the powders that prevents neck formation until after all the surfactant has volatilized. A striking feature of the IR spectra collected on the iron oxide powders is the absence of peaks in the ~1715 cm(-1) to 1750 cm(-1) region, where absorption due to the symmetric C=O (carbonyl) stretching occurs. The lack of such peaks strongly suggests the carbonyl group is no longer free, but is actively participating in the surfactant-precipitate interaction. The final two microemulsion systems, containing CTAB as the surfactant, showed that loss of control of the reverse micelle synthesis process can easily occur when the amount of salt in the water domains exceeds a critical concentration. Both model systems eventually resulted in agglomerated powders of broad size distributions or particles that were large compared to the sizes of the reverse micelles, consistent with the notion that the microemulsions were not stable and the powders were precipitated in an uncontrolled fashion. This has implications for the synthesis of nanopowders by reverse micelle synthesis and provides a benchmark for process control if powders of the highest quality are desired. PMID:23906861

Graeve, Olivia A; Fathi, Hoorshad; Kelly, James P; Saterlie, Michael S; Sinha, Kaustav; Rojas-George, Gabriel; Kanakala, Raghunath; Brown, David R; Lopez, Enrique A

2013-10-01

382

Saltation threshold reduction due to the electrostatic agglomeration of fine particles  

NASA Technical Reports Server (NTRS)

Particles between 80 and 110 microns in diameter are the most easily moved by the wind. As the particle size decreases below 60 microns, they are increasingly more difficult to move by surface winds, and a number of experiments were performed in an attempt to reduce the required wind velocity. These include: (1) the bombardment of a bed of fine particles by particles near the optimum size, the larger particles kicking the fine particles into the windstream where they are entrained; and (2) the electrostatic agglomeration of fine particles into sizes more easily saltated. The results of these experiments are discussed.

Leach, Rodman N.; Greeley, Ronald

1991-01-01

383

Role of Additives in Controlling Agglomeration and Defluidization During Fluidized Bed Combustion of High-Sodium, High-Sulphur Low-Rank Coal  

NASA Astrophysics Data System (ADS)

Four additives have been tested to determine their effectiveness in controlling ash deposition, agglomeration and defluidization under circulating fluidized bed combustor conditions. Gibbsite was found to be most effective. The evidence obtained from the various analytical techniques suggests that depending on the type of additive used, interference in the process of ash deposition may be due to either a chemical reaction or physical dilution. These interactions apparently occur at the surface of burning char particles. Although previous investigations have identified clays to be effective in sodium capture, care must be taken in selection of clay additives since the mineralogical composition of the clays appears to play a major role in the extent of deposit formation control. Gibbsite and the clays have demonstrated potential for in-situ sodium capture which may facilitate use of low-rank coals in advanced FBC-based power generation plants.

Linjewile, Temi M.; Manzoori, Alan R.

384

Influence of oxalic acid on the agglomeration process and total soda content in precipitated Al(OH) 3  

NASA Astrophysics Data System (ADS)

Decomposition of caustic soda solutions is an important part of Bayer process for alumina production. The physico-chemical properties of precipitated Al(OH) 3 are dependent on several processes that take place simultaneously during the decomposition process and they are: nucleation, agglomeration and Al(OH) 3 crystals. An important industrial requirement is increase of Al(OH) 3 crystal grain size, and hence agglomeration and growth of Al(OH) 3 crystals become important processes and they enable increase of particle size. The influence of oxalic acid concentration on the agglomeration process and total soda content in precipitated Al(OH) 3 at different temperatures and caustic soda concentrations has been investigated. The results have shown that the agglomeration process is increased with increase of temperature and decrease of caustic soda concentration. Total soda content in precipitated Al(OH) 3 is changed in the same way. Besides, agglomeration process of Al(OH) 3 particles is favored in the presence of oxalic acid.

Nikoli?, I.; Blec?i?, D.; Blagojevi?, N.; Radmilovi?, V.; Kovac?evi?, K.

2003-05-01

385

Physical simulation of precipitation of radioactive element oxalates by using the harmless neodymium oxalate for studying the agglomeration phenomena  

NASA Astrophysics Data System (ADS)

Oxalic precipitation is usually applied in nuclear industry to process radioactive wastes or to recover actinides from a multicomponent solution. This paper deals with the development of methods adapted to a nuclear environment in order to study the agglomeration phenomena during actinide oxalic precipitation. These methods are previously setup with harmless elements that simulate the actinide behaviour: the lanthanides. A parametric study is carried out to quantify the influence of operating parameters on the agglomeration kernel and to determine a kinetic law for this mechanism. The experimental study is performed in a continuous-MSMPR precipitator at steady-state. The method is based on the resolution of two population balances using the moment approach, one for elementary crystals and the other for agglomerates. Provided that the kinetic rates of nucleation and growth are known, the agglomeration kernel can be obtained from a mathematical treatment of the experimental particle size distributions. Results point out that experimental crystal sizes are consistent with an independent kernel. It appears that the agglomeration kernel is directly proportional to supersaturation, increases with temperature but is limited by ionic strength and shear rate.

Lalleman, Sophie; Bertrand, Murielle; Plasari, Edouard

2012-03-01

386

A micromanipulation particle tester for agglomeration contact mechanism studies in a controlled environment  

NASA Astrophysics Data System (ADS)

Pressure agglomeration of powders is widely applied in various industries and an increasing interest lies in the identification and description of contact mechanisms between particles, which are responsible for the compaction product properties. In this paper, the design and development of a novel micromanipulation particle tester (MPT) is presented. This device makes it possible to measure the deformation kinetics and resulting adhesion of two individual particles in contact under load, which are strongly influenced by the applied process conditions. The MPT set-up is, therefore, designed to offer a unique control over the process conditions most relevant to the compaction of powders: external stress, dwell or holding time at constant deformation, compression velocity as well as relative humidity and temperature determining the physical state and mechanical characteristics of hygrosensitive amorphous particles. The latter are often part of powder formulations, e.g. in the food industry, and have been used for force and contact-zone development studies with the MPT. The experimental results on the microscale level will deliver valuable quantitative information for an improved tailoring of pressure agglomeration process conditions of bulk solids.

Haider, C. I.; Althaus, T.; Niederreiter, G.; Hounslow, M. J.; Palzer, S.; Salman, A. D.

2012-10-01

387

Study of thermal environment in Jingjintang urban agglomeration based on WRF model and Landsat data  

NASA Astrophysics Data System (ADS)

In recent decades, unprecedented urban expansion has taken place in developing countries resulting in the emergence of megacities or urban agglomeration. It has been highly concerned by many countries about a variety of urban environmental issues such as greenhouse gas emissions and urban heat island phenomenon associated with urbanization. Generally, thermal environment is monitored by remote sensing satellite data. This method is usually limited by weather and repeated cycle. Another approach is relied on numerical simulation based on models. In the study, these two means are combined to study the thermal environment of Jingjintang urban agglomeration. The high temperature processes of the study area in 2009 and 1990s are simulated by using WRF (the Weather Research and Forecasting Model) coupled with UCM (Urban Canopy Model) and the urban impervious surface estimated from Landsat-5 TM data using support vector machine. Results show that the trend of simulated air temperature (2 meter) is in accord with observed air temperature. Moreover, it indicates the differences of air temperature and Land Surface Temperature caused by the urbanization efficiently. The UHI effect at night is stronger than that in the day. The maximum difference of LST reaches to 8-10°C for new build-up area at night. The method provided in this research can be used to analyze impacts on urban thermal environment caused by urbanization and it also provides means on thermal environment monitoring and prediction which will benefit the coping capacity of extreme event.

Huang, Q. N.; Cao, Z. Q.; Guo, H. D.; Xi, X. H.; Li, X. W.

2014-03-01

388

Nano crystalline ceria-neodymia solid solutions by combustion route: effect of agglomeration on powder properties.  

PubMed

About 8 compositions in the system Ce(1-x)Nd(x)O(2-x/2) (0.0 < or = x < or = 0.50) were prepared by the combustion process using glycine as a fuel and corresponding metal nitrates as the oxidants. The oxidant-to-fuel ratio was taken as 1:1.0. The products were characterized by X-ray diffraction (XRD), surface area, scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering, sinterability etc. The crystallite size of powders, as obtained by the line broadening method, was typically in the range of 7 to 16 nm. The deagglomeration studies carried out showed that the average agglomerate size of these powders increases with increasing content of Nd in CeO2. The powders were sintered at 1200 degrees C to yield densities in the range of 80-95% of theoretical densities. This wide variation in the sintered density was explained based on the powder properties. An interesting observation was that the nature and size of the agglomerates plays an important role in governing properties such as sintered density and in turn ionic conductivity of nano ceramics. PMID:18019152

Bedekar, Vinila; Tyagi, A K

2007-09-01

389

Evaluation of water security: an integrated approach applied in Wuhan urban agglomeration, China.  

PubMed

To evaluate water security, the Water Resources Sustainability Evaluation Model has been developed. The model employs four criteria (economic development, flood control security, water supply security, and water environment security) and has 22 indicators, integrating them using their relative weights. The model is applied to evaluate the water security of Wuhan urban agglomeration, China. The values of the indicators are normalized using the exponential efficacy functions based on the law of diminishing marginal utility. The evaluation results show that, overall, the state of water security in Wuhan urban agglomeration is good, which is in good agreement with the true situation. The comparison between the results of the model and other three evaluation methods by the Spearman coefficient of rank correlation verifies the science and reliability of the developed model. Consequently, it is concluded that the model can be an effective tool for evaluating the states of water security and provide a basis on which to create policies for improving inadequacies in water security. PMID:22678203

Shao, Dongguo; Yang, Fengshun; Xiao, Chun; Tan, Xuezhi

2012-01-01

390

Agglomeration multigrid methods with implicit Runge-Kutta smoothers applied to aerodynamic simulations on unstructured grids  

NASA Astrophysics Data System (ADS)

For unstructured finite volume methods an agglomeration multigrid with an implicit multistage Runge-Kutta method as a smoother is developed for solving the compressible Reynolds averaged Navier-Stokes (RANS) equations. The implicit Runge-Kutta method is interpreted as a preconditioned explicit Runge-Kutta method. The construction of the preconditioner is based on an approximate derivative. The linear systems are solved approximately with a symmetric Gauss-Seidel method. To significantly improve this solution method grid anisotropy is treated within the Gauss-Seidel iteration in such a way that the strong couplings in the linear system are resolved by tridiagonal systems constructed along these directions of strong coupling. The agglomeration strategy is adapted to this procedure by taking into account exactly these anisotropies in such a way that a directional coarsening is applied along these directions of strong coupling. Turbulence effects are included by a Spalart-Allmaras model, and the additional transport-type equation is approximately solved in a loosely coupled manner with the same method. For two-dimensional and three-dimensional numerical examples and a variety of differently generated meshes we show the wide range of applicability of the solution method. Finally, we exploit the GMRES method to determine approximate spectral information of the linearized RANS equations. This approximate spectral information is used to discuss and compare characteristics of multistage Runge-Kutta methods.

Langer, Stefan

2014-11-01

391

The potential use of sequences of fibonacci series to simulate breakage and agglomeration  

NASA Astrophysics Data System (ADS)

Simulations were conducted to investigate the use of discrete size classes defined by sequences of interlaced Fibonacci series to describe particle breakage and agglomeration. The method was used to examine the evolution of various mean diameters for repeated ternary breakage events that yielded two equal-sized daughters and a smaller satellite. An inverse algorithm was also developed to extract size-dependent breakage frequencies from sequential size distribution measurements. Simulated mean diameters were found to depend weakly upon the assumed progeny distribution. Similarly, retrieved breakage frequencies were found to be insensitive to the assumed breakage rule. When agglomeration is considered, it is not possible to limit the resulting products to the discrete sizes which define each of the size classes. It was therefore necessary to develop an algorithm for adjusting particle numbers between bins so that mass was conserved. Simulations were carried out for constant and Brownian kernels and the results were compared with exact solutions of the Smoluchowski equation for constant kernels.

Zhang, N.; Chang, Y. C.; Calabrese, R. V.; Gentry, J. W.

392

Integrated low emission cleanup system for direct coal-fueled turbines (electrostatic agglomeration)  

SciTech Connect

The objective of this contract is to investigate the removal of So{sub x} and particulate matter from direct coal-fired combustion gas streams at high temperature and high pressure conditions. This investigation will be accomplished through a bench-scale testing and evaluation program employing sorbent mixed with a coal-water slurry for So{sub x} removal, and an innovative particulate control concept. The particulate control device utilizes electrostatic agglomeration followed by a high efficiency mechanical collector (cyclone). The process goal is to achieve particulate collection efficiency better than that required by the 1979 new source performance standards. An additional goal is to demonstrate 70% So{sub x} removal efficiency. This research project is now in the second of a 3 phase (Phase II) project. Phase II is to fabricate the combustor and particulate control devices and install the system at a test facility located at Research-Cottrell's, KVB Western Laboratory, Santa Ana, CA. There are three functional categories, or tasks which are to be completed in sequence. These tasks are itemized as follows: Design, procurement, and installation; Shakedown and startup; Reporting. Attempts to validate the concept of electrostatic agglomeration were not possible in the shakedown program before budget constraints halted the program. What was learned was that electrostatic precipitation is feasible in the temperature range of 1600--1800{degrees}F and at pressures above 10 atmospheres.

Quimby, J.M.

1992-02-01

393

Peppermint Oil  

MedlinePLUS

... and bowel conditions such as irritable bowel syndrome. Essential oil of peppermint may be found in very small doses in capsule or liquid forms. The essential oil can also be diluted with another oil and ...

394

BIOREMEDIATION TECHNIQUES ON CRUDE OIL CONTAMINATED SOILS IN OHIO. Final report includes the quarterly report that ended 12\\/31\\/1996  

Microsoft Academic Search

The purpose of this study is to define the optimum limits of chemical and physical conditions that reduce soil salinity and maximize indigenous aerobic microbiological populations in the bioremediation of oil field waste solids. Specifically, the study centers around treatment of surface contained oily waste having low density and limited solubility in water. Successful remediation is defined by total petroleum

David A. Hodges; Richard J. Simmers

1997-01-01

395

Inoculation of Bacillus sphaericus UPMB-10 to Young Oil Palm and Measurement of Its Uptake of Fixed Nitrogen Using the 15N Isotope Dilution Technique  

PubMed Central

There are increasing applications of diazotrophic rhizobacteria in the sustainable agriculture system. A field experiment on young immature oil palm was conducted to quantify the uptake of N derived from N2 fixation by the diazotroph Bacillus sphaericus strain UPMB-10, using the 15N isotope dilution method. Eight months after 15N application, young immature oil palms that received 67% of standard N fertilizer application together with B. sphaericus inoculation had significantly lower 15N enrichment than uninoculated palms that received similar N fertilizers. The dilution of labeled N served as a marker for the occurrence of biological N2 fixation. The proportion of N uptake that was derived from the atmosphere was estimated as 63% on the whole plant basis. The inoculation process increased the N and dry matter yields of the palm leaflets and rachis significantly. Field planting of young, immature oil palm in soil inoculated with B. sphaericus UPMB-10 might mitigate inorganic fertilizer-N application through supplementation by biological nitrogen fixation. This could be a new and important source of nitrogen biofertilizer in the early phase of oil palm cultivation in the field. PMID:22446306

Zakry, Fitri Abdul Aziz; Shamsuddin, Zulkifli H.; Rahim, Khairuddin Abdul; Zakaria, Zin Zawawi; Rahim, Anuar Abdul

2012-01-01

396

High efficiency shale oil recovery  

SciTech Connect

The overall project objective is to demonstrate the high efficiency of the Adams Counter-Current shale oil recovery process. The efficiency will first be demonstrated on a small scale, in the current phase, after which the demonstration will be extended to the operation of a small pilot plant. Thus the immediate project objective is to obtain data on oil shale retorting operations in a small batch rotary kiln that will be representative of operations in the proposed continuous process pilot plant. Although an oil shale batch sample is sealed in the batch kiln from the start until the end of the run, the process conditions for the batch are the same as the conditions that an element of oil shale would encounter in a continuous process kiln. Similar chemical and physical (heating, mixing) conditions exist in both systems. The two most important data objectives in this phase of the project are to demonstrate (1) that the heat recovery projected for this project is reasonable and (2) that an oil shale kiln will run well and not plug up due to sticking and agglomeration. The following was completed and is reported on this quarter: (1) A software routine was written to eliminate intermittently inaccurate temperature readings. (2) We completed the quartz sand calibration runs, resolving calibration questions from the 3rd quarter. (3) We also made low temperature retorting runs to identify the need for certain kiln modifications and kiln modifications were completed. (4) Heat Conductance data on two Pyrolysis runs were completed on two samples of Occidental oil shale.

Adams, D.C.

1992-01-01

397

Comparative study of different clean-up techniques for the determination of ?-cyhalothrin and cypermethrin in palm oil matrices by gas chromatography with electron capture detection.  

PubMed

Solid phase extraction (SPE) and dispersive solid-phase extraction (d-SPE) were compared and evaluated for the determination of ?-cyhalothrin and cypermethrin in palm oil matrices by gas chromatography with an electron capture detector (GC-ECD). Several SPE sorbents such as graphitised carbon black (GCB), primary secondary amine (PSA), C(18), silica, and florisil were tested in order to minimise fat residues. The results show that mixed sorbents using GCB and PSA obtained cleaner extracts than a single GCB and PSA sorbents. The average recoveries obtained for each pesticide ranged between 81% and 114% at five fortification levels with the relative standard deviation of less than 7% in all cases. The limits of detection for these pesticides were ranged between 0.025 and 0.05 ?g/g. The proposed method was applied successfully for the residue determination of both ?-cyhalothrin and cypermethrin in crude palm oil samples obtained from local mills throughout Malaysia. PMID:23442715

Muhamad, Halimah; Zainudin, Badrul Hisyam; Abu Bakar, Nor Kartini

2012-10-15

398

Application of solid phase-microextraction (SPME) and electronic nose techniques to differentiate volatiles of sesame oils prepared with diverse roasting conditions.  

PubMed

Headspace volatiles of sesame oil (SO) from sesame seeds roasted at 9 different conditions were analyzed by a combination of solid phase microextraction (SPME)-gas chromatography/mass spectrometry (GC/MS), electronic nose/metal oxide sensors (MOS), and electronic nose/MS. As roasting temperature increased from 213 to 247 °C, total headspace volatiles and pyrazines increased significantly (P < 0.05). Pyrazines were major volatiles in SO and furans, thiazoles, aldehydes, and alcohols were also detected. Roasting temperature was more discrimination factor than roasting time for the volatiles in SO through the principal component analysis (PCA) of SPME-GC/MS, electronic nose/MOS, and electronic nose/MS. Electronic nose/MS showed that ion fragment 52, 76, 53, and 51 amu played important roles in discriminating volatiles in SO from roasted sesame seeds, which are the major ion fragments from pyrazines, furans, and furfurals. SO roasted at 213, 230, and 247 °C were clearly differentiated from each other on the base of volatile distribution by SPME-GC/MS, electronic nose/MOS, and electronic nose/MS analyses. Practical Application: The results of this study are ready to apply for the discriminating samples using a combinational analysis of volatiles. Not only vegetable oils prepared from roasting process but also any food sample possessing volatiles could be targets for the SPME-GC/MS and electronic nose assays. Contents and types of pyrazines in sesame seed oil could be used as markers to track down the degree of roasting and oxidation during oil preparation. PMID:21535659

Park, Min Hee; Jeong, Min Kyu; Yeo, JuDong; Son, Hee-Jin; Lim, Chae-Lan; Hong, Eun Jeung; Noh, Bong-Soo; Lee, JaeHwan

2011-01-01

399

Water quality studied in areas of unconventional oil and gas development, including areas where hydraulic fracturing techniques are used, in the United States  

USGS Publications Warehouse

The U.S. Geological Survey (USGS) John Wesley Powell Center for Analysis and Synthesis is hosting an interdisciplinary working group of USGS scientists to conduct a temporal and spatial analysis of surface-water and groundwater quality in areas of unconventional oil and gas development. The analysis uses existing national and regional datasets to describe water quality, evaluate water-quality changes over time where there are sufficient data, and evaluate spatial and temporal data gaps.

Susong, David D.; Gallegos, Tanya J.; Oelsner, Gretchen P.

2012-01-01

400

Mixing of nanosize particles by magnetically assisted impaction techniques  

NASA Astrophysics Data System (ADS)

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.

Scicolone, James V.

401

Increased oil production and reserves utilizing secondary/tertiary recovery techniques on small reservoirs in the Paradox basin, Utah. Annual report  

SciTech Connect

The Paradox basin of Utah, Colorado, and Arizona contains nearly 100 small oil fields producing from carbonate buildups or mounds within the Pennsylvanian (Desmoinesian) Paradox Formation. These fields typically have one to four wells with primary production ranging from 700,000 to 2,000,000 barrels of oil per field at a 15 to 20% recovery rate. At least 200 million barrels of oil is at risk of being unrecovered in these small fields because of inefficient recovery practices and undrained heterogeneous reservoirs. Five fields (Anasazi, mule, Blue Hogan, heron North, and Runway) within the Navajo Nation of southeastern utah are being evaluated for waterflood or carbon-dioxide-miscible flood projects based upon geological characterization and reservoir modeling. The results can be applied to other fields in the Paradox basin and the Rocky Mountain region, the Michigan and Illinois basins, and the Midcontinent. The reservoir engineering component of the work completed to date included analysis of production data and well tests, comprehensive laboratory programs, and preliminary mechanistic reservoir simulation studies. A comprehensive fluid property characterization program was completed. Mechanistic reservoir production performance simulation studies were also completed.

Chidsey, T.C. Jr.

1997-02-01

402

Calorimetry for Fast Authentication of Edible Oils  

NASA Astrophysics Data System (ADS)

There are little data in the literature on how to authenticate edible oils through calorimetry techniques. However, oil melting curves can be used to represent correlations between calorimetric results and oil quality. A calorimetric method has been developed for studying the solid-liquid phase transitions of olive oil and seed oils, in which melting peak behavior is correlated to the type, quality, and composition of the oil. Good reproducible thermograms were obtained by defining precise protocols for use in testing, which take into account the specific characteristics of a particular oil. This approach does not replace classical analytical methods; nevertheless, it is believed that calorimetric tests could be a useful preliminary stage for quality testing. The calorimetric technique allows the detection of the adulterant (seed oils or refined olive oil), oil origin, and possible photo-oxidation degradation processes, before more complex and expensive procedures and analyses are applied.

Angiuli, Marco; Bussolino, Gian Carlo; Ferrari, Carlo; Matteoli, Enrico; Righetti, Maria Cristina; Salvetti, Giuseppe; Tombari, Elpidio

2009-06-01

403

Aerobic enhanced oil recovery: analysis of the mechanisms and a pilot study  

E-print Network

The technique that uses microorganisms to improve oil production in petroleum reservoirs is known as microbial enhanced oil recovery (MEOR). Aerobic microbial enhanced oil recovery is a method which is based on stimulating indigenous oil degrading...

Eide, Karen

2012-06-07

404

Differences between satellite- and ground-based urban heat island effect - Case study for the Budapest agglomeration area  

NASA Astrophysics Data System (ADS)

Urban heat island (UHI) is defined as the positive temperature anomaly occurring between built-in areas and their surroundings. For detailed analysis of UHI in a particular area, different approaches can be used. Here, two different techniques (ground-based and satellite-based) are applied to the Budapest agglomeration area and the results are compared. (1) Hourly recorded air temperature observations are available from six automatically operating climatological stations of the Hungarian Meteorological Service. Two stations are located in the downtown of Budapest (Kitaibel Pál street and Lágymányos); two stations can be found in the suburbs (Újpest and Pestszentl?rinc); and two stations are in the rural region (Penc - located to the northeast from the capital, and Kakucs - to the southeast from Budapest). These ground-based observations at the Budapest weather stations provide air temperature data at standard 2 m height above surface. However, due to the limited station number, this approach is not suitable for detailed evaluation of spatial UHI distribution. (2) Remotely sensed surface temperature values are available from seven thermal infrared channel measurements of the multi-spectral radiometer sensor called MODIS (Moderate Resolution Imaging Spectroradiometer), which is one of the sensors on-board satellites Terra and Aqua. They were launched to polar orbit as part of the NASA's Earth Observing System in December 1999, and in May 2002, respectively. Satellite Terra (Aqua) provides surface temperature fields around 09-10 UTC (12-13 UTC) and 20-21 UTC (02-03 UTC) with 1 km spatial resolution. The whole agglomeration has been divided into urban and rural pixels using the MODIS Land Cover Product categories, distance from the city centre, satellite images of the Google Earth, and GTOPO-30 global digital elevation model. However, the main disadvantage of this method is that for UHI analysis, data can be used only in case of clear sky conditions, which occurs less frequently in the Carpathian basin during winter than summer. The purpose of the present research is to analyze similarities and differences between temperature values observed in the 2001-2010 period by ground-based and satellite-based instruments. Thus, monthly and seasonal mean temperature values for day-time (morning and afternoon) and night-time (late evening and before dawn) are evaluated and compared for Budapest and its vicinity. Furthermore, distribution of temperature values is analyzed on a seasonal scale. On the basis of the results, the following main conclusions can be summarized. (i) The mean temperature is generally higher in the downtown and lower in the rural region than in the suburbs, especially, at night-time. During day-time it is not so clear, the suburbs may be warmer than the downtown stations. (ii) Day-time/night-time satellite-based surface temperature is higher/lower than ground-based air temperature (especially, in summer/winter). This can be explained by the faster warming and faster cooling of the surface than those of the atmosphere. (iii) The satellite-based average temperature of Kakucs and Penc is highly correlated to the rural mean surface temperature. Thus, the mean temperature of the rural region can be estimated by the average temperature of these two weather stations. Moreover, the UHI intensity can be defined as the difference between the actual temperature value and the average temperature of Kakucs and Penc. This time series are calculated from both ground-based and satellite-based temperature values. (iv) The UHI intensity shows a large temporal variability. During day-time intensity values are larger when the satellite-based method is used than the ground-based measurements. During night-time the difference between the two approaches is very small.

Pongracz, R.; Bartholy, J.; Lelovics, E.; Dezso, Z. S.; Dobi, I.

2012-04-01

405

Oil Spill!  

ERIC Educational Resources Information Center

An oil spill occurs somewhere in the world almost every day of the year, and the consequences can be devastating. In this month's column, students explore the effects of oil spills on plants, animals, and the environment and investigate oil spill clean-up methods through a simulated oil spill. The activities described in this article give students…

Ansberry, Karen Rohrich; Morgan, Emily

2005-01-01

406

Motor oil  

NSDL National Science Digital Library

Motor oil can be recycled and reused, cutting down on our foreign oil dependence. It can also contaminate drinking water and harm beach shore sand, as well as birds. Birds covered in oil cannot fly again until all the oil is washed off.

N/A N/A (None;)

2007-02-11

407

HETEROGENEOUS SHALLOW-SHELF CARBONATE BUILDUPS IN THE PARADOX BASIN, UTAH AND COLORADO: TARGETS FOR INCREASED OIL PRODUCTION AND RESERVES USING HORIZONTAL DRILLING TECHNIQUES  

SciTech Connect

The Paradox Basin of Utah, Colorado, Arizona, and New Mexico contains nearly 100 small oil fields producing from carbonate buildups within the Pennsylvanian (Desmoinesian) Paradox Formation. These fields typically have one to 10 wells with primary production ranging from 700,000 to 2,000,000 barrels (111,300-318,000 m{sup 3}) of oil per field and a 15 to 20 percent recovery rate. At least 200 million barrels (31.8 million m{sup 3}) of oil will not be recovered from these small fields because of inefficient recovery practices and undrained heterogeneous reservoirs. Several fields in southeastern Utah and southwestern Colorado are being evaluated as candidates for horizontal drilling and enhanced oil recovery from existing, vertical, field wells based upon geological characterization and reservoir modeling case studies. Geological characterization on a local scale is focused on reservoir heterogeneity, quality, and lateral continuity, as well as possible reservoir compartmentalization, within these fields. This study utilizes representative cores, geophysical logs, and thin sections to characterize and grade each field's potential for drilling horizontal laterals from existing development wells. The results of these studies can be applied to similar fields elsewhere in the Paradox Basin and the Rocky Mountain region, the Michigan and Illinois Basins, and the Midcontinent region. This report covers research activities for the first half of the third project year (April 6 through October 5, 2002). This work included capillary pressure/mercury injection analysis, scanning electron microscopy, and pore casting on selected samples from Cherokee and Bug fields, Utah. The diagenetic fabrics and porosity types found at these fields are indicators of reservoir flow capacity, storage capacity, and potential for enhanced oil recovery via horizontal drilling. The reservoir quality of Cherokee and Bug fields has been affected by multiple generations of dissolution, anhydrite plugging, and various types of cementation which act as barriers or baffles to fluid flow. The most significant diagenetic characteristics are microporosity (Cherokee field) and micro-boxwork porosity (Bug field), as shown from porethroat radii histograms, and saturation profiles generated from the capillary pressure/mercury injection analysis, and identified by scanning electron microscopy and pore casting. These porosity types represent important sites for untapped hydrocarbons and primary targets for horizontal drilling. Technology transfer activities consisted of exhibiting a booth display of project materials at the Rocky Mountain Section meeting of the American Association of Petroleum Geologists, a technical presentation, and publications. The project home page was updated for the Utah Geological Survey Internet web site.

Thomas C. Chidsey, Jr.

2002-12-01

408

Megacities and large urban agglomerations in the coastal zone: interactions between atmosphere, land, and marine ecosystems.  

PubMed

Megacities are not only important drivers for socio-economic development but also sources of environmental challenges. Many megacities and large urban agglomerations are located in the coastal zone where land, atmosphere, and ocean meet, posing multiple environmental challenges which we consider here. The atmospheric flow around megacities is complicated by urban heat island effects and topographic flows and sea breezes and influences air pollution and human health. The outflow of polluted air over the ocean perturbs biogeochemical processes. Contaminant inputs can damage downstream coastal zone ecosystem function and resources including fisheries, induce harmful algal blooms and feedback to the atmosphere via marine emissions. The scale of influence of megacities in the coastal zone is hundreds to thousands of kilometers in the atmosphere and tens to hundreds of kilometers in the ocean. We list research needs to further our understanding of coastal megacities with the ultimate aim to improve their environmental management. PMID:23076973

von Glasow, Roland; Jickells, Tim D; Baklanov, Alexander; Carmichael, Gregory R; Church, Tom M; Gallardo, Laura; Hughes, Claire; Kanakidou, Maria; Liss, Peter S; Mee, Laurence; Raine, Robin; Ramachandran, Purvaja; Ramesh, R; Sundseth, Kyrre; Tsunogai, Urumu; Uematsu, Mitsuo; Zhu, Tong

2013-02-01

409

Mechanisms for agglomeration and deagglomeration following oblique collisions of wet particles  

NASA Astrophysics Data System (ADS)

Previous studies on wetted, particle-particle collisions have been limited to head-on collisions, but in many-particle flows, collisions are inherently oblique. In this work, we explore such oblique collisions experimentally and theoretically. Whereas in normal collisions particles rebound only due to solid deformation, we observe in oblique collisions a new outcome where the particles initially form a rotating doublet and then deagglomerate at a later time due to so-called centrifugal forces. Surprisingly, we discover the essential role of capillary forces in oblique collisions even when the capillary number (viscous over capillary forces) is high. This recognition leads to the introduction of a dimensionless number, the centrifugal number (centrifugal over capillary forces), which together with the previously established Stokes number characterizes the regime map of outcomes. Unexpectedly, we observe a normal restitution coefficient greater than unity at large impact angles, the mechanism for which may also be observed in other agglomerating systems.

Donahue, Carly M.; Davis, Robert H.; Kantak, Advait A.; Hrenya, Christine M.

2012-08-01

410

Time-dependent analysis of agglomerating Pt thin films on YSZ single crystals  

NASA Astrophysics Data System (ADS)

The controlled assembly of nanostructures via shape instability mechanisms is a potential alternative to traditional top-down processes like e-beam lithography for nanostructuring surfaces. In this contribution, the dynamics of the nanostructures' assembly via thin film agglomeration have been analyzed. Pt thin films with a thickness of 50 nm were deposited via magnetron sputtering on yttria-stabilized zirconia (YSZ) single crystals and subjected to heat treatments at 1023 K for times ranging from 10 to 130 min. The morphological evolution of Pt thin films has been investigated by means of scanning electron microscopy (SEM) and atomic force microscopy (AFM), obtaining the hole growth dynamics and morphological parameters like the lateral correlation length and the nanostructures' Minkowski functionals. The experimentally obtained morphology evolution is compared to the simulated evolution of thin film structures resulting from a cell dynamical system (CDS) model. Three main observations have been made. (i) The hole radius is found to scale as function of time t with a rate proportional to t[log3t]. This is in agreement with Srolovitz's instability theory describing hole growth predominated by surface diffusion. (ii) The morphological evolution of the Pt thin films has been analyzed as function of time t by means of Minkowski measures and the lateral correlation length. A discontinuity in the lateral correlation length and a significant deviation of the Minkowski functionals from the expected Gaussian behavior was found to be coupled with the coalescence of holes. (iii) By using the Ginzburg-Landau equation for the description of the fundamental diffusion process, the CDS model allows a computational reproduction of the experimentally obtained film morphologies in the early stages of agglomeration.

Galinski, Henning; Ryll, Thomas; Schlagenhauf, Lukas; Schenker, Iwan; Spolenak, Ralph; Gauckler, Ludwig J.

2013-08-01

411

Simple Techniques For Assessing Impacts Of Oil And Gas Operations On Public Lands: A Field Evaluation Of A Photoionization Detector (PID) At A Condensate Release Site, Padre Island National Seashore, Texas  

USGS Publications Warehouse

Simple, cost-effective techniques are needed for land managers to assess the environmental impacts of oil and gas production activities on public lands, so that sites may be prioritized for remediation or for further, more formal assessment. Field-portable instruments provide real-time data and allow the field investigator to extend an assessment beyond simply locating and mapping obvious disturbances. Field investigators can examine sites for the presence of hydrocarbons in the subsurface using a soil auger and a photoionization detector (PID). The PID measures volatile organic compounds (VOC) in soil gases. This allows detection of hydrocarbons in the shallow subsurface near areas of obvious oil-stained soils, oil in pits, or dead vegetation. Remnants of a condensate release occur in sandy soils at a production site on the Padre Island National Seashore in south Texas. Dead vegetation had been observed by National Park Service personnel in the release area several years prior to our visit. The site is located several miles south of the Malaquite Beach Campground. In early 2001, we sampled soil gases for VOCs in the area believed to have received the condensate. Our purpose in this investigation was: 1) to establish what sampling techniques might be effective in sandy soils with a shallow water and contrast them with techniques used in an earlier study; and 2) delineate the probable area of condensate release. Our field results show that sealing the auger hole with a clear, rigid plastic tube capped at the top end and sampling the soil gas through a small hole in the cap increases the soil VOC gas signature, compared to sampling soil gases in the bottom of an open hole. This sealed-tube sampling method increases the contrast between the VOC levels within a contaminated area and adjacent background areas. The tube allows the PID air pump to draw soil gas from the volume of soil surrounding the open hole below the tube in a zone less influenced by atmospheric air. In an open hole, the VOC readings seem to be strongly dependent on the degree of diffusion and advection of soil gas VOCs into the open hole from the surrounding soil, a process that may vary with soil and wind conditions. Making measurements with the sealed hole does take some additional time (4-7 minutes after the hole is augered) compared to the open-hole technique (1-2 minutes). We used the rigid-plastic tube technique to survey for soil gas VOCs across the entire site, less than ? acre. Condensate has impacted at least 0.28 acres. The impacted area may extend northwest of the surveyed area.

Otton, James K.; Zielinski, Robert A.

2001-01-01

412

Effects of caustic sodium concentration and molecular ratio of Na2O to Al2O3 on agglomeration in the precipitation process  

NASA Astrophysics Data System (ADS)

The supersaturation of sodium aluminate solution (liquor) is a prerequisite for agglomeration and the key factors that determine supersaturation of liquor are caustic sodium concentration (Nk) and molecular ratio of Na2O to Al2O3 (?k). In this paper, the effects of Nk and ?k on the agglomeration process of seeded precipitation were studied. The results show that the Nk plays an important role in the agglomeration process. The supersaturation of liquor decreases with the increasing of Nk and so not only does the precipitation ratio of liquor decrease but also the particle size of agglomerate decreases. The supersaturation of liquor decreases with the increasing of ?k and so the precipitation rate and depth of liquor decrease and thus the agglomeration of fine particles is weakened.

Liu, Zhanwei; Chen, Wenmi; Li, Wangxing

2010-11-01

413

THE PHYSICS OF PROTOPLANETESIMAL DUST AGGLOMERATES. VI. EROSION OF LARGE AGGREGATES AS A SOURCE OF MICROMETER-SIZED PARTICLES  

SciTech Connect

Observed protoplanetary disks consist of a large amount of micrometer-sized particles. Dullemond and Dominik pointed out for the first time the difficulty in explaining the strong mid-infrared excess of classical T Tauri stars without any dust-retention mechanisms. Because high relative velocities in between micrometer-sized and macroscopic particles exist in protoplanetary disks, we present experimental results on the erosion of macroscopic agglomerates consisting of micrometer-sized spherical particles via the impact of micrometer-sized particles. We find that after an initial phase, in which an impacting particle erodes up to 10 particles of an agglomerate, the impacting particles compress the agglomerate's surface, which partly passivates the agglomerates against erosion. Due to this effect, the erosion halts for impact velocities up to {approx}30 m s{sup -1} within our error bars. For higher velocities, the erosion is reduced by an order of magnitude. This outcome is explained and confirmed by a numerical model. In a next step, we build an analytical disk model and implement the experimentally found erosive effect. The model shows that erosion is a strong source of micrometer-sized particles in a protoplanetary disk. Finally, we use the stationary solution of this model to explain the amount of micrometer-sized particles in the observational infrared data of Furlan et al.

Schraepler, Rainer; Blum, Juergen, E-mail: r.schraepler@tu-bs.de [Institut fuer Geophysik und extraterrestrische Physik, University of Braunschweig, Mendelssohnstr. 3, D-38106 Braunschweig (Germany)

2011-06-20

414

Physical simulation of precipitation of radioactive element oxalates by using the harmless neodymium oxalate for studying the agglomeration phenomena  

Microsoft Academic Search

Oxalic precipitation is usually applied in nuclear industry to process radioactive wastes or to recover actinides from a multicomponent solution. This paper deals with the development of methods adapted to a nuclear environment in order to study the agglomeration phenomena during actinide oxalic precipitation. These methods are previously setup with harmless elements that simulate the actinide behaviour: the lanthanides. A

Sophie Lalleman; Murielle Bertrand; Edouard Plasari

415

World Urbanization Prospects: The 1994 Revision. Estimates and Projections of Urban and Rural Populations and of Urban Agglomerations.  

ERIC Educational Resources Information Center

This publication presents data from the current revision of estimates and projections of the size and growth of urban and rural populations for all countries of the world. The publication also contains revised estimates and projections for all urban agglomerations of at least 750,000 inhabitants in 1994. The revisions are part of a series of…

United Nations New York, NY. Dept. of Economic and Social Information and Policy Analysis.

416

On the conceptualization of agglomeration economies: The case of new firm formation in the Dutch ICT sector  

Microsoft Academic Search

In this research we look at the factors that determine new firm formation in the information and communications technology (ICT) sector among 580 municipalities in the Netherlands. In particular, we examine the role of agglomeration economies and other locational attributes in determining where new firms locate. Both proximity (contiguous) and heterogeneous (non-contiguous) structures at the local, regional and national level

Frank G. van Oort; Oedzge A. L. C. Atzema

2004-01-01

417

Increased oil production and reserves utilizing secondary/tertiary recovery techniques on small reservoirs in the Paradox basin, Utah. Annual report, February 9, 1996--February 8, 1997  

SciTech Connect

The Paradox basin of Utah, Colorado, and Arizona contains nearly 100 small oil fields producing from carbonate buildups or mounds within the Pennsylvanian (Desmoinesian) Paradox Formation. These fields typically have one to four wells with primary production ranging from 700,000 to 2,000,000 barrels of oil per field at a 15 to 20% recovery rate. At least 200 million barrels of oil is at risk of being unrecovered in these small fields because of inefficient recovery practices and undrained heterogeneous reservoirs. Five fields (Anasazi, Mule, Blue Hogan, Heron North, and Runway) within the Navajo Nation of southeastern Utah are being evaluated for waterflood or carbon-dioxide-miscible flood projects based upon geological characterization and reservoir modeling. The results can be applied to other fields in the Paradox basin and the Rocky Mountain region, the Michigan and Illinois basins, and the Midcontinent. The Anasazi field was selected for the initial geostatistical modeling and reservoir simulation. A compositional simulation approach is being used to model primary depletion, waterflood, and CO{sub 2}-flood processes. During this second year of the project, team members performed the following reservoir-engineering analysis of Anasazi field: (1) relative permeability measurements of the supra-mound and mound-core intervals, (2) completion of geologic model development of the Anasazi reservoir units for use in reservoir simulation studies including completion of a series of one-dimensional, carbon dioxide-displacement simulations to analyze the carbon dioxide-displacement mechanism that could operate in the Paradox basin system of reservoirs, and (3) completion of the first phase of the full-field, three-dimensional Anasazi reservoir simulation model, and the start of the history matching and reservoir performance prediction phase of the simulation study.

Chidsey, T.C. Jr.

1997-08-01

418

Effect of Agglomeration on the Toxicity of Nano-sized Carbon Black in Sprague-Dawley Rats  

PubMed Central

Objectives Recent studies have shown that nano-sized carbon black is more toxic than large respirable carbon black because of its higher surface area. However, it is not clear if carbon black made larger by agglomeration demonstrates decreased toxicity. The purpose of this study was to verify if agglomeration affects the toxicity of carbon black using three differently prepared nano-sized carbon black aerosols in nose-only inhalation chambers for 13 weeks. Methods Printex 90 was selected as a representative nano-sized carbon black. To generate aerosols of three different types of agglomerates, Printex 90 was dispersed in distilled water by three different methods: vortex, vortex+sonication, and vortex+sonication with dispersion in a stabilizer. Then, the three differently prepared solutions were aerosolized through venturi nozzles. Male Sprague-Dawley rats were exposed to Printex 90 aerosols in a nose-only exposure chamber for 6 h/d, 5 d/wk for 13 weeks at a concentration of approximately 9 mg/m3. Results Numbers of total cells in the bronchoalveolar lavage (BAL) fluid, macrophages, and polymorphonuclear leukocytes were increased and carbon black masses were clearly seen in BAL cells and lung tissues of rats exposed to Printex 90. However, few differences were found between the three differently agglomerated aerosols. In addition, there were no significant differences in other parameters, such as body weight, lung function or cytokine levels in BAL fluid following carbon black exposure. Conclusions Only mild to moderate respiratory effects were found in rats exposed to nano-sized carbon black at 9 mg/m3 for 13 weeks. Agglomeration did not affect the toxicity of nano-sized carbon particles. PMID:23106037

Kang, Mingu; Han, Jeong-Hee; Yang, Jeong-Sun

2012-01-01

419

Application of multivariate chemometric techniques for simultaneous determination of five parameters of cottonseed oil by single bounce attenuated total reflectance Fourier transform infrared spectroscopy.  

PubMed

Single bounce attenuated total reflectance (SB-ATR) Fourier transform infrared (FTIR) spectroscopy in conjunction with chemometrics was used for accurate determination of free fatty acid (FFA), peroxide value (PV), iodine value (IV), conjugated diene (CD) and conjugated triene (CT) of cottonseed oil (CSO) during potato chips frying. Partial least square (PLS), stepwise multiple linear regression (SMLR), principal component regression (PCR) and simple Beer?s law (SBL) were applied to develop the calibrations for simultaneous evaluation of five stated parameters of cottonseed oil (CSO) during frying of French frozen potato chips at 170°C. Good regression coefficients (R(2)) were achieved for FFA, PV, IV, CD and CT with value of >0.992 by PLS, SMLR, PCR, and SBL. Root mean square error of prediction (RMSEP) was found to be less than 1.95% for all determinations. Result of the study indicated that SB-ATR FTIR in combination with multivariate chemometrics could be used for accurate and simultaneous determination of different parameters during the frying process without using any toxic organic solvent. PMID:25127621

Talpur, M Younis; Kara, Huseyin; Sherazi, S T H; Ayyildiz, H Filiz; Topkafa, Mustafa; Arslan, Fatma Nur; Naz, Saba; Durmaz, Fatih; Sirajuddin

2014-11-01

420

Application of /sup 13/C NMR, fluorescence, and light-scattering techniques for structural studies of oil-in-water microemulsions  

SciTech Connect

The nature of the microdroplets present in oil-in-water microemulsions was examined by using the 4-component model system water-hexadecane-sodium hexadecyl sulfate-pentanol. Three compositions were selected corresponding to regions in the pahse diagram where the content of water, cosurfactant, and oil, respectively, approached the tolerable limit to yield clear isotropic solutions. In the water-side microemulsion, the radius of the droplets is 127A as determined from quasi-elastic light-scattering measurements. Fluorescence experiments showed that the core of the microspheres has a microviscosity similar to hexadecane at room temperature. /sup 13/C NMR shift analysis was applied to test the partitioning of cosurfactant between the surface and the interior of the droplet. For all three compositions significant fractions of the cosurfactant are present in the interior. This is corroborated by results obtained from T/sub 1/ relaxation-time analysis at different field strengths. The influence of the field strength on T/sub 1/ is explained in terms of a model based on a distribution of correlation times. In particular, the importance of taking into account slower rotational modes such as the tumbling of the whole microsphere is illustrated.

Tricot, Y.; Kiwi, J.; Niederberger, W.; Graetzel, M.

1981-04-02

421

Mode-switching: A new technique for electronically varying the agglomeration position in an acoustic particle manipulator  

Microsoft Academic Search

Acoustic radiation forces offer a means of manipulating particles within a fluid. Much interest in recent years has focussed on the use of radiation forces in microfluidic (or “lab on a chip”) devices. Such devices are well matched to the use of ultrasonic standing waves in which the resonant dimensions of the chamber are smaller than the ultrasonic wavelength in

Peter Glynne-Jones; Rosemary J. Boltryk; Nicholas R. Harris; Andy W. J. Cranny; Martyn Hill

2010-01-01

422

Fluorescence characteristics of oil during the Deepwater Horizon oil spill  

Microsoft Academic Search

Emergency responders, agencies and researchers have tracked oil spilled during the Deepwater Horizon event using a number of techniques, including fluorescence, particle size and chemical analyses. Even though current protocols call for the use of in situ fluorometers to detect the presence of oil throughout the water column, these fluorometers have not been designed to yield information on changes in

P. G. Coble; R. N. Conmy; M. Wood; K. Lee; P. Kepkay; Z. Li

2010-01-01

423

Mineral oils  

NASA Technical Reports Server (NTRS)

The characteristics of lubricants made from mineral oils are discussed. Types and compositions of base stocks are reviewed and the product demands and compositions of typical products are outlined. Processes for commercial production of mineral oils are examined. Tables of data are included to show examples of product types and requirements. A chemical analysis of three types of mineral oils is reported.

Furby, N. W.

1973-01-01

424