WorldWideScience

Sample records for agglomeration

  1. Defining urban agglomerations to detect agglomeration economies

    CERN Document Server

    Cottineau, Clementine; Hatna, Erez; Arcaute, Elsa; Batty, Michael

    2016-01-01

    Agglomeration economies are a persistent subject of debate among economists and urban planners. Their definition turns on whether or not larger cities and regions are more efficient and more productive than smaller ones. We complement existing discussion on agglomeration economies and the urban wage premium here by providing a sensitivity analysis of estimated coefficients to different delineations of urban agglomeration as well as to different definitions of the economic measure that summarises the urban premium. This quantity can consist of total wages measured at the place of work, or of income registered at the place of residence. The chosen option influences the scaling behaviour of city size as well as the spatial distribution of the phenomenon at the city level. Spatial discrepancies between the distribution of jobs and the distribution of households at different economic levels makes city definitions crucial to the estimation of economic relations which vary with city size. We argue this point by regr...

  2. Agglomeration and Market Interaction

    OpenAIRE

    Fujita, Masahisa; Thisse, Jacques-François

    2002-01-01

    The most salient feature of the spatial economy is the presence of a large variety of economic agglomerations. Our purpose is to review some of the main explanations for this universal phenomenon, as they are proposed in urban economics and modern economic geography. We first show why the competitive framework can hardly be the foundation for the economics of agglomeration. We then briefly review the alternative modelling strategies. In the hope of making our Paper accessible to a broad audie...

  3. Agglomeration and Co-Agglomeration of Services Industries

    OpenAIRE

    Kolko, Jed

    2007-01-01

    Economic research on industry location and agglomeration has focused nearly exclusively on manufacturing. This paper shows that services are prominent among the most agglomerated industries, especially at the county level. Because traditional measures of knowledge spillovers, natural resource inputs, and labor pooling explain little of agglomeration in services industries, this paper takes an alternative approach and looks at co-agglomeration to assess why industries cluster together. By cons...

  4. Agglomeration Economies in Classical Music

    DEFF Research Database (Denmark)

    Borowiecki, Karol Jan

    2015-01-01

    This study investigates agglomeration effects for classical music production in a wide range of cities for a global sample of composers born between 1750 and 1899. Theory suggests a trade-off between agglomeration economies (peer effects) and diseconomies (peer crowding). I test this hypothesis...

  5. Optical scattering on ferrofluid agglomerates

    OpenAIRE

    Bacri, J. -C.; Salin, D.

    1982-01-01

    Direct microscopic observation of a thin sample of ionic ferrofluid, in the presence of a magnetic field, shows the existence of a locally hexagonal lattice of agglomerates. We have observed the unusual pattern of the light scattered by this array.

  6. Nucleation of point defect agglomerates

    International Nuclear Information System (INIS)

    A theory of the agglomeration of point defects into dislocation loops and voids is formulated. A critical comparison between theory and experiment is made for nickel and copper irradiated in a high voltage electron microscope

  7. Optimal agglomerations in dynamic economics

    OpenAIRE

    Brock, William A.; Xepapadeas, Anastasios; Athanasios. N. Yannacopoulos

    2012-01-01

    We study rational expectations equilibrium problems and social optimum problems in innite horizon spatial economies in the context of a Ramsey type capital accumulation problem with geographical spillovers. We identify sufficient local and global conditions for the emergence (or not) of optimal agglomeration, using techniques from monotone operator theory and spectral theory in innite dimensional Hilbert spaces. We show that agglomerations may emerge, with any type of returns to scale (increa...

  8. Agglomeration processes in aging societies

    OpenAIRE

    Theresa Grafeneder-Weissteiner; Klaus Prettner

    2010-01-01

    This article investigates agglomeration processes in aging societies by introducing an overlapping generation structure into a New Economic Geography model. Whether higher economic integration leads to spatial concentration of economic activity crucially hinges on the economies' demographic properties. While population aging as represented by declining birth rates strengthens agglomeration processes, declining mortality rates weaken them. This is due to the fact that we allow for nonconstant ...

  9. Microbial effects on colloidal agglomeration

    International Nuclear Information System (INIS)

    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

  10. Microbial effects on colloidal agglomeration

    Energy Technology Data Exchange (ETDEWEB)

    Hersman, L.

    1995-11-01

    Colloidal particles are known to enhance the transport of radioactive metals through soil and rock systems. This study was performed to determine if a soil microorganism, isolated from the surface samples collected at Yucca Mountain, NV, could affect the colloidal properties of day particles. The agglomeration of a Wyoming bentonite clay in a sterile uninoculated microbial growth medium was compared to the agglomeration in the medium inoculated with a Pseudomonas sp. In a second experiment, microorganisms were cultured in the succinate medium for 50 h and removed by centrifugation. The agglomeration of the clay in this spent was compared 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.

  11. The problem of providing food resources in urban agglomerations (the case study of the Kuzbass agglomeration)

    OpenAIRE

    ZOBOVA L.L.; SHABASHEV V.A.

    2016-01-01

    Urban agglomerations are the result of a process of spatial competition for resources. To analyze the functioning of specific urban centers, it is necessary to make a distinction between the process of agglomeration and the state of agglomeration in the spatial structure. This paper shows the interrelation of the process of urban agglomeration and the agglomeration of the production activity as its economic foundation. The study reveals the connection between the urban agglomeration process a...

  12. Metal extraction by solid-liquid agglomerates

    International Nuclear Information System (INIS)

    Dissolved metal values are extracted from a liquid e.g. uranium from phosphoric acid by contacting the liquid with agglomerates for a time to load the agglomerate with the metal value, separating the loaded agglomerates from the liquid phase and stripping the metal value from the loaded agglomerate. The agglomerate may be made by combining finely divided solid particles with a binding liquid to form a paste, adding a suspending liquid to form a mixture, the suspending liquid and binding liquid being immiscible in each other and the solid particles being insoluble in the suspending liquid and shearing the mixture to form the agglomerate. (author)

  13. Agglomeration and networks in spatial economies

    OpenAIRE

    Johansson, Börje; Quigley, John M.

    2004-01-01

    We consider the parallel developments in the economics of agglomeration and the economics of networks. We explore the complementarities between the productivity benefits of agglomeration and those of network linkages, arguing that networks of actors dispersed over space may substitute for agglomerations of actors at a single point.

  14. Agglomeration effects : studying agglomeration e ffects from Norwegian hydroelectricity plants

    OpenAIRE

    Johansen, Marius; Risa, Erling

    2015-01-01

    This thesis aims to answer the research question \\To what extent did the shocks to eco- nomic activity and population following openings of Norwegian hydroelectricity plants in the early 20th century lead to long run agglomeration eff ects?". The question is answered using data on population density and taxable income in 67 Norwegian municipalities in the period between 1876 and 2013. We utilize the fact that hydroelectricity plants opened before transportation of electricity o...

  15. Agglomeration, Integration and Tax Harmonization

    OpenAIRE

    Richard Baldwin; Paul Krugman

    2001-01-01

    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 monopolists toward less advanced 'periphery' countries. Consequently, integration need not ...

  16. Agglomeration of food powder and applications.

    Science.gov (United States)

    Dhanalakshmi, K; Ghosal, S; Bhattacharya, S

    2011-05-01

    Agglomeration has many applications in food processing and major applications include easy flow table salt, dispersible milk powder and soup mix, instant chocolate mix, beverage powder, compacted cubes for nutritional-intervention program, health bars using expanded/puffed cereals, etc. The main purpose of agglomeration is to improve certain physical properties of food powders such as bulk density, flowability, dispersability, and stability. Agglomerated products are easy to use by the consumers and hence are preferred over the traditional non-agglomerated products that are usually non-flowable in nature. The properties of food agglomerates and the process of agglomeration like employing pressure, extrusion, rewetting, spray-bed drying, steam jet, heat/sintering, and binders have been reviewed. The physical and instant properties of agglomerated food products have also been discussed. PMID:21491268

  17. Mechanisms for selective agglomeration of coals

    Energy Technology Data Exchange (ETDEWEB)

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

    1989-05-01

    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.

  18. Agglomeration and the product mix

    OpenAIRE

    Dalvai, Wilfried

    2016-01-01

    Worldwide trade flows are dominated by high-productivity firms, that have a large range of products. Since the product range of firms reflects partly trade flows, it is a source of economic differences in space. In this paper, I analyze the effects of the product mix of firms on agglomeration. I build a theoretical model of multiproduct firms à la Mayer, Melitz, and Ottaviano (2014, AER), expand it with skilled, mobile workers and a spatial equilibrium. I show that a larger product mix of fir...

  19. Human Capital, Talent, Agglomeration and Regional Growth

    OpenAIRE

    Karlsson, Charlie; Johansson, Börje; Stough, Roger R.

    2009-01-01

    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? There are different underlying agglomerative forces creating spatially concentrated increasing re...

  20. Industrial Scope of Agglomeration Economies in Brazil

    OpenAIRE

    Ana Maria Bonomi Barufi; Eduardo A. Haddad, Peter Nijkamp

    2015-01-01

    The tendency towards urbanization in the emerging world accompanied by the constant pursuit for higher productivity prompts an urge for studies aiming at understanding agglomeration economies. In the context of Brazil, a country with extremely high regional disparities, exploring this issue is important not only for private stakeholders, but also for public policy practitioners. In the framework of static agglomeration effects, we investigate the industrial scope of agglomeration economies in...

  1. SPHERICAL AGGLOMERATION – DIRECT TABLETTING TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Patil Pradnya B.

    2011-11-01

    Full Text Available Direct tabletting technique is the modern and the most efficient process used in tablet manufacturing and has been successfully employed for various poorly soluble and poorly compressible drugs. Spherical agglomeration is particle engineering technique which involves the transformation of fine crystals into spherical shape particles which enhances the powder properties such as particle size, shape, flow properties, solubility and bioavailability of pharmaceutical drug substances. This technique can also be applied to sustain the drug release from solid dosage forms. The present article is on the detailed comprehensive review about advantages and disadvantages, mechanism, different manufacturing methods of spherical agglomerates and characterization of spherical agglomerates.

  2. Agglomeration of microparticles in complex plasmas

    CERN Document Server

    Du, Cheng-Ran; Ivlev, Alexei; Konopka, Uwe; Morfill, Gregor

    2010-01-01

    Agglomeration of highly charged microparticles was observed and studied in complex plasma experiments carried out in a capacitively coupled rf discharge. The agglomeration was caused by strong dust density waves triggered in a particle cloud by decreasing neutral gas pressure. Using a high-speed camera during this unstable regime, it was possible to resolve the motion of individual microparticles and to show that the relative velocities of some particles were sufficiently high to overcome the mutual Coulomb repulsion and hence to result in agglomeration. After stabilising the cloud again through the increase of the pressure, we were able to observe the aggregates directly with a long-distance microscope. We show that the agglomeration rate deduced from our experiments is in good agreement with theoretical estimates. In addition, we briefly discuss the mechanisms that can provide binding of highly charged microparticles in a plasma.

  3. Advances in food powder agglomeration engineering.

    Science.gov (United States)

    Cuq, B; Gaiani, C; Turchiuli, C; Galet, L; Scher, J; Jeantet, R; Mandato, S; Petit, J; Murrieta-Pazos, I; Barkouti, A; Schuck, P; Rondet, E; Delalonde, M; Dumoulin, E; Delaplace, G; Ruiz, T

    2013-01-01

    Food powders are used in everyday life in many ways and offer technological solutions to the problem of food production. The natural origin of food powders, diversity in their chemical composition, variability of the raw materials, heterogeneity of the native structures, and physicochemical reactivity under hydrothermal stresses contribute to the complexity in their behavior. Food powder agglomeration has recently been considered according to a multiscale approach, which is followed in the chapter layout: (i) at the particle scale, by a presentation of particle properties and surface reactivity in connection with the agglomeration mechanisms, (ii) at the mechanisms scale, by describing the structuration dynamics of agglomerates, (iii) at the process scale, by a presentation of agglomeration technologies and sensors and by studying the stress transmission mode in the powder bed, and finally (iv) by an integration of the acquired knowledge, thanks to a dimensional analysis carried out at each scale. PMID:23522795

  4. Agglomeration process engineering approach to evaluate the ability of different technologies to agglomerate food powder.

    OpenAIRE

    Hafsa, Ines; Mandato, Sandra; Lafond, Charleyne; Mejean, Serge; Dolivet, Anne; jin Kim, S.; Chevallier, S.; Le Bail, A.; Ruiz, Thierry; Cuq, Bernard

    2012-01-01

    Agglomeration technologies are considered as a relevant way to improve functionalities of food powders. The agglomeration process makes it possible to limit segregation phenomena, to reduce dust production, to improve wettability and powders hydration during use, etc. Although largely used in the field of dairy or cereal food products, agglomeration processes are still managed with more or less empirical approaches, and tools. The objective of the present study is to investigate the agglomera...

  5. Correcting agglomeration economies: How air pollution matters

    OpenAIRE

    Drut, Marion; Mahieu, Aurélie

    2015-01-01

    This paper aims to correct standard measures of agglomeration economies to account for air pollution generated by commuting. This paper examines the impact of nitrogen oxide (NOX) ? a pollutant mainly released by transportation ? on worker productivity. On one side, literature on agglomeration economies highlights the positive role of employment density on productivity, without accounting for the environmental impact of a better accessibility. On the other side, several studies (Graham, 2007;...

  6. Agglomeration of Charged Nanopowders in Suspensions

    OpenAIRE

    Werth, J. H.; Linsenbuehler, M.; Dammer, S. M.; Farkas, Z.; Hinrichsen, H.; Wirth, K. -E.; Wolf, D. E.

    2002-01-01

    The aim of this work is to understand agglomeration of charged powders suspended in nonpolar fluids. The concerted influence of electromagnetic, hydrodynamic and van der Waals forces as well as Brownian motion leads to a complex agglomeration behaviour which depends on several parameters, e.g., the ratios of electric charges, particle sizes, temperature and concentrations of the particles. Both experimental and theoretical considerations are presented.

  7. The magnitude and causes of agglomeration economies

    OpenAIRE

    Diego Puga

    2009-01-01

    Firms and workers are much more productive in large and dense urban environments. There is substantial evidence of such agglomeration economies based on three aproaches. First, on a clustering of production beyond what can be explained by chance or comparative advantage. Second, on spatial patterns in wages and rents. Third, on systematic variations in productivity with the urban environment. However, more needs to be learned about the causes of agglomeration economies. We have good models of...

  8. Control of optical active borates nanocrystals agglomeration

    OpenAIRE

    I. Cieślik; R. Węgłowski; J. Żmija; K. Kurzydłowski; M. Płocińska; M. Oćwieja

    2013-01-01

    Purpose: The purposes of this study explore the possibility of total control the agglomeration of nanoborates powders. The great potential of PDLCs can be enhanced by using dye-doped or nanoparticles-doped materials, such as borates [1]. It is important to know how to prepare nanoparticles in order to obtain a high level of dispersion in the composites. Otherwise, even small an agglomeration does not give a possibility on the appropriate characteristic of properties and interp...

  9. Industrial Agglomeration and Use of the Internet

    OpenAIRE

    Chang, Chia-Lin; McAleer, Michael; Wu, Yu-Chieh

    2015-01-01

    textabstractTaiwan has been hailed as a world leader in the development of global innovation and industrial clusters for the past decade. This paper investigates the effects of industrial agglomeration on the use of the internet and internet intensity for Taiwan manufacturing firms, and analyses whether the relationships between industrial agglomeration and total expenditure on internet usage for industries are substitutes or complements. The sample observations are based on 153,081 manufactu...

  10. Industrial Agglomeration and Use of the Internet

    OpenAIRE

    Chang, C-L; McAleer, M.J.; Wu, Y-C

    2015-01-01

    Taiwan has been hailed as a world leader in the development of global innovation and industrial clusters for the past decade. This paper investigates the effects of industrial agglomeration on the use of the internet and internet intensity for Taiwan manufacturing firms, and analyses whether the relationships between industrial agglomeration and total expenditure on internet usage for industries are substitutes or complements. The sample observations are based on 153,081 manufacturing plants,...

  11. Theoretical studies on aerosol agglomeration processes

    Energy Technology Data Exchange (ETDEWEB)

    Lehtinen, K.E.J. [VTT Energy, Espoo (Finland). Energy Use

    1997-12-31

    In this thesis, theoretical modeling of certain aerosol systems has been presented. At first, the aerosol general dynamic equation is introduced, along with a discretization routine for its numerical solution. Of the various possible phenomena affecting aerosol behaviour, this work is mostly focused on aerosol agglomeration. The fundamentals of aerosol agglomeration theory are thus briefly reviewed. The two practical applications of agglomeration studied in this thesis are flue gas cleaning using an electrical agglomerator and nanomaterial synthesis with a free jet reactor. In an electrical agglomerator the aerosol particles are charged and brought into an alternating electric field. The aim is to remove submicron particles from flue gases by collisions with larger particles before conventional gas cleaning devices that have a clear penetration window in the problematic 0.1-1{mu}m size range. A mathematical model was constructed to find out the effects of the different system parameters on the agglomerator`s performance. A crucial part of this task was finding out the collision efficiencies of particles of varying size and charge. The original idea was to use unipolar charging of the particles, and a laboratory scale apparatus was constructed for this purpose. Both theory and experiments clearly show that significant removal of submicron particles can not be achieved by such an arrangement. The theoretical analysis further shows that if the submicron particles and the large collector particles were charged with opposite polarity, significant removal of the submicron particles could be obtained. The second application of agglomeration considered in this thesis is predicting/controlling nanoparticle size in the gas-to-particle aerosol route to material synthesis. In a typical material reactor, a precursor vapor reacts to form molecules of the desired material. In a cooling environment, a particulate phase forms, the dynamics of which are determined by the rates of

  12. Compression Behaviour of Porous Dust Agglomerates

    CERN Document Server

    Seizinger, Alexander; Kley, Wilhelm

    2012-01-01

    The early planetesimal growth proceeds through a sequence of sticking collisions of dust agglomerates. Very uncertain is still the relative velocity regime in which growth rather than destruction can take place. The outcome of a collision depends on the bulk properties of the porous dust agglomerates. Continuum models of dust agglomerates require a set of material parameters that are often difficult to obtain from laboratory experiments. Here, we aim at determining those parameters from ab-initio molecular dynamics simulations. Our goal is to improveon the existing model that describe the interaction of individual monomers. We use a molecular dynamics approach featuring a detailed micro-physical model of the interaction of spherical grains. The model includes normal forces, rolling, twisting and sliding between the dust grains. We present a new treatment of wall-particle interaction that allows us to perform customized simulations that directly correspond to laboratory experiments. We find that the existing i...

  13. Measuring Agglomeration Forces in a Financial Center

    OpenAIRE

    Bourgain, Arnaud; Pieretti, Patrice

    2006-01-01

    Basing on Scitovsky's (1954) definition of external economies and applying the method of Caballero and Lyons (1990) to macro data of Luxembourg services industry, we find significant agglomeration forces between financial intermediaries (downstream industry) on the one hand and business services and computer industry (upstream industries) on the other.

  14. Industrial Agglomeration and Use of the Internet

    NARCIS (Netherlands)

    C-L. Chang (Chia-Lin); M.J. McAleer (Michael); Y-C. Wu (Yu-Chieh)

    2015-01-01

    textabstractTaiwan has been hailed as a world leader in the development of global innovation and industrial clusters for the past decade. This paper investigates the effects of industrial agglomeration on the use of the internet and internet intensity for Taiwan manufacturing firms, and analyses whe

  15. Bipolar charged aerosol agglomeration and collection by a two zone agglomerator

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In older to collect fine particles more efficiently, a new-type electrostatic agglomerator with two sones was developed. The distinguishing feature of this electrostatic agglomerator is that the particles are bipolarly charged and coagulated in the same alternating electric field simultaneously. The silica flour with 2 μm mass median diameter and the smoke from burning wood powder were used as test aerosol. The comparison experimental results have shown that when the mean electric field is 4 kV/cm the collection efficiency of the new electrostatic agglomerator was 98.2% for silica flour and 67.4% for wood powder smoke. Under the same experimental condition, the collection efficiency of the electrostatic agglomerator with three zones was 97.4% for collecting silica flour and the collection efficiency of the electrostatic precipitator was 56.3% for wood powder smoke.

  16. Filtration behavior of silver nanoparticle agglomerates and effects of the agglomerate model in data analysis

    International Nuclear Information System (INIS)

    In many data evaluation procedures for particle measuring devices and in filtration models, spherical particles are assumed. However, significant fractions of aerosol particles are agglomerates of small primary spheres. The morphology of particles in filtration processes may not be known a priori and if the filtration data are processed with wrong assumption, errors can be induced. In this work, we have quantified such errors for the case of open-structured agglomerates. Filtration efficiency tests with polydisperse silver nanoparticle agglomerates and their sintered spheres were performed. After the sintering process, particles with a compact structure with the shape close to a sphere are obtained, which are referred to as sintered spheres in the present study. The testing method involved generation of particulate forms, passing the particles through the testing section, and measurement of the particle number concentrations and size distributions before and after the filter. Measurements of the aerosols upstream and downstream of the filter were conducted using scanning mobility particle sizers (SMPS, TSI Inc.), which covered the rage from 10 to 480 nm. Particles were additionally characterized from the electron microscopic images and the average primary particle size was determined to be 16.8 nm. The number-size distribution curves were obtained and used for penetration calculation. The penetration was dependent on the particle size and morphology. Silver-sintered spheres were captured with a lower efficiency than agglomerates with the same mobility diameter because of the stronger interception effect for agglomerates. Data analysis of the number-size distribution for agglomerates was processed based on sphere assumption and using the model for open-structured agglomerates developed by Lall and Friedlander. The efficiencies based on total concentrations of number, surface and volume were affected when the agglomerate model was used. The effect was weakest for the

  17. Filtration behavior of silver nanoparticle agglomerates and effects of the agglomerate model in data analysis

    Energy Technology Data Exchange (ETDEWEB)

    Buha, Jelena, E-mail: jelena.buha@empa.ch [Empa, Analytical Chemistry (Switzerland); Fissan, Heinz [Institute of Energy and Environmental Technology e.V. (IUTA) (Germany); Wang, Jing, E-mail: jing.wang@ifu.baug.ethz.ch [Empa, Analytical Chemistry (Switzerland)

    2013-07-15

    In many data evaluation procedures for particle measuring devices and in filtration models, spherical particles are assumed. However, significant fractions of aerosol particles are agglomerates of small primary spheres. The morphology of particles in filtration processes may not be known a priori and if the filtration data are processed with wrong assumption, errors can be induced. In this work, we have quantified such errors for the case of open-structured agglomerates. Filtration efficiency tests with polydisperse silver nanoparticle agglomerates and their sintered spheres were performed. After the sintering process, particles with a compact structure with the shape close to a sphere are obtained, which are referred to as sintered spheres in the present study. The testing method involved generation of particulate forms, passing the particles through the testing section, and measurement of the particle number concentrations and size distributions before and after the filter. Measurements of the aerosols upstream and downstream of the filter were conducted using scanning mobility particle sizers (SMPS, TSI Inc.), which covered the rage from 10 to 480 nm. Particles were additionally characterized from the electron microscopic images and the average primary particle size was determined to be 16.8 nm. The number-size distribution curves were obtained and used for penetration calculation. The penetration was dependent on the particle size and morphology. Silver-sintered spheres were captured with a lower efficiency than agglomerates with the same mobility diameter because of the stronger interception effect for agglomerates. Data analysis of the number-size distribution for agglomerates was processed based on sphere assumption and using the model for open-structured agglomerates developed by Lall and Friedlander. The efficiencies based on total concentrations of number, surface and volume were affected when the agglomerate model was used. The effect was weakest for the

  18. Fibre agglomerate transport in a horizontal flow

    International Nuclear Information System (INIS)

    Loss of coolant accidents in the primary circuit of pressure and boiling water reactors can cause the damage of adjacent insulation materials. These materials may then find their way to the containment sump where water is drawn into the ECCS (emergency core cooling system). Strainers in the containment sump may become fully or partially blocked by the insulation materials. The consequences of such blockages are an increased pressure drop acting on the operating ECCS pumps. If the strainers are partially blocked smaller particles can also penetrate the strainers. These smaller particles can therefore enter the reactor coolant system and then accumulate in the reactor pressure vessel. An experimental and theoretical study that concentrates on mineral wool fibre transport in the containment sump and the ECCS is being performed. The study entails the generation of fibre agglomerates and the assessment of their transport in single and multi-effect experiments. The experiments include measurement of the terminal settling velocity, the strainer pressure drop, fibre sedimentation and resuspension in a channel flow, jet flow in a rectangular tank and the importance of chemical effects on any filter cake formed on the strainer. An integrated test facility is also operated to assess the compounded effects. Each experimental facility is used to provide data for the validation of equivalent computational fluid dynamic models. The channel flow facility allows the determination of the steady state distribution of the fibres at different flow velocities. The channel has a racetrack configuration with nine straight sections (1 m by 1 m by 0.1 m) and two 90 deg. bends with a radius of 0.5 m to the channel midpoint. The height of the bends is also 1 m and the channel width is 0.1 m. An elliptical section located upstream of one of the bends is used to house the impellers, which drives the flow into the next bend. Laser Doppler anemometry, particle image velocimetry, ultrasound

  19. Industry-specific firm growth and agglomeration

    OpenAIRE

    Duschl, Matthias; Scholl, Tobias; Brenner, Thomas; Luxen, Dennis; Raschke, Falk

    2013-01-01

    This paper studies the industry-specific relationship between industrial clustering and firm growth. The literature usually considers industrial clusters as positive for the general economic development of regions. In particular, their relationship with the formation rate of new firms and the survival rate of existing firms is well documented. However, the impact of agglomeration effects on growth prospects of firms is less clear. Because of the heterogeneity of industries, different agglomer...

  20. Sports Facilities, Agglomeration, and Urban Redevelopment

    OpenAIRE

    Humphreys, Brad; Zhou, Li

    2013-01-01

    We develop a monopolistic competition model of urban service consumption and production that includes spatial structure and property values. The model shows that the introduction of a new professional sports facility and team generates agglomeration effects that change the mix of services and property values, and increases local welfare, part of which is transferred to the team as subsidies for the construction of the facility. The distributional consequences of the new facility and the impli...

  1. Specialization and Agglomeration Patterns in Eastern Europe

    Directory of Open Access Journals (Sweden)

    Chapman, Sheila A.

    2013-04-01

    Full Text Available The paper investigates specialization and agglomeration trends in EU-27 NUTS2 regions over 1991-2011 by means of two versions of the relative Theil indicator that use employment data. The paper’s main focus is on Central and Eastern European Countries (CEECs regions. As a legacy of central planning, in the early ‘Nineties these regions presented significantly above-average specialization and agglomeration. The paper shows that over 1991-2011 these features change very little; moreover, while disproportions fall in the other EU members, they rise in CEECs, implying growing divergence among the two groups in real terms, notwithstanding EU emphasis on real convergence. Indicators disaggregated by sectors show that for CEECs specialization/agglomeration change most in agriculture, market services and manufacturing. The paper focuses on the last two sectors. It argues that performance in the service sector is largely due to capital regions catching up on previous underdevelopment in the sector, therefore getting closer to Western regions. Non-capital regions instead lag behind, moving away from the EU sectoral average. As far as manufacturing is concerned, CEECs regions continue to specialize in the more traditional lines of production, for which also agglomeration remains extremely high. Consideration of the changes over time gives a partially different picture and shows that the higher specialization in overall manufacturing results from the development of a small but dynamic medium-high technology sub-sector that is significantly disseminated across regions, thus appearing to result from successful industrial restructuring and reconversion.

  2. Encapsulation of hazardous wastes into agglomerates

    International Nuclear Information System (INIS)

    The objective of this study was to investigate the feasibility of using the cementitious properties and agglomeration characteristics of coal conversion byproducts to encapsulate and immobilize hazardous waste materials. The intention was to establish an economical way of co-utilization and co-disposal of wastes. In addition, it may aid in the eradication of air pollution problems associated with the fine-powdery nature of fly ash. Encapsulation into agglomerates is a novel approach of treating toxic waste. Although encapsulation itself is not a new concept, existing methods employ high-cost resins that render them economically unfeasible. In this investigation, the toxic waste was contained in a concrete-like matrix whereby fly ash and other cementitious waste materials were utilized. The method incorporates the principles of solidification, stabilization and agglomeration. Another aspect of the study is the evaluation of the agglomeration as possible lightweight aggregates. Since fly ash is commercially used as an aggregate, it would be interesting to study the effect of incorporating toxic wastes in the strength development of the granules. In the investigation, the fly ash self-cementation process was applied to electroplating sludges as the toxic waste. The process hoped to provide a basis for delisting of the waste as hazardous and, thereby greatly minimize the cost of its disposal. Owing to the stringent regulatory requirements for hauling and disposal of hazardous waste, the cost of disposal is significant. The current practice for disposal is solidifying the waste with portland cement and dumping the hardened material in the landfill where the cost varies between $700--950/ton. Partially replacing portland cement with fly ash in concrete has proven beneficial, therefore applying the same principles in the treatment of toxic waste looked very promising

  3. The Power of Hydroelectric Dams: Agglomeration Spillovers

    OpenAIRE

    Severnini, Edson R.

    2014-01-01

    How much of the geographic clustering of economic activity is attributable to agglomeration spillovers as opposed to natural advantages? I present evidence on this question using data on the long-run effects of large scale hydroelectric dams built in the U.S. over the 20th century, obtained through a unique comparison between counties with or without dams but with similar hydropower potential. Until mid-century, the availability of cheap local power from hydroelectric dams conveyed an importa...

  4. Control of optical active borates nanocrystals agglomeration

    Directory of Open Access Journals (Sweden)

    I. Cieślik

    2013-12-01

    Full Text Available Purpose: The purposes of this study explore the possibility of total control the agglomeration of nanoborates powders. The great potential of PDLCs can be enhanced by using dye-doped or nanoparticles-doped materials, such as borates [1]. It is important to know how to prepare nanoparticles in order to obtain a high level of dispersion in the composites. Otherwise, even small an agglomeration does not give a possibility on the appropriate characteristic of properties and interpretation of the results. The deagglomeration methods applied until now give the decrease of agglomeration to a lesser extent than our method. Characteristic size and shape of particles made with sol-gel process is difficult to perform. Design/methodology/approach: Nanopowders samples of YAB and LCBO were prepared with sol-gel method. Deagglomeration process was carried out using acetic acid. The morphology and size of nanopowders were investigated by scanning electron microscopy (SEM. The crystallite sizes were determinated with IPS UA method. Findings: It was confirmed that the acetic acid influence on the decrease of agglomeration. It was also determined of conditions for preparation borates nanopowders samples (concentration acetic acind time and temperature of drying prepared samples. We have proved that a reagent used for deagglomeration process does not affect the structure of the investigated nanoborates used in an experimental. Research limitations/implications: The results can be used to the prepared of nanocompades of borates to observe a morphology and reliable assessment of nanocrystalline size. Originality/value: Our study shows how to prepare a sample of particles to observe morphology and measure the size of nanograins. In our study we found excellent solution, the medium, which not influence the inorganic nanomaterial structure. Result seems to be excellent and very perspective. We have showed as that measurement type influence the results of particles size.

  5. Development of a Gas-Promoted Oil Agglomeration Process

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-11-01

    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.

  6. Agglomeration defects on irradiated carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Steini Moura, Cassio [Faculty of Physics, Pontificia Universidade Catolica do Rio Grande do Sul, 90619-900, Porto Alegre, RS (Brazil); Balzaretti, Naira Maria; Amaral, Livio [Institute of Physics, Universidade Federal do Rio Grande do Sul, C.P.: 15051, 91501-070, Porto Alegre, RS (Brazil); Gribel Lacerda, Rodrigo; Pimenta, Marcos A. [Universidade Federal de Minas Gerais, C.P.: 702, 31270-901, Belo Horizonte, MG (Brazil)

    2012-03-15

    Aligned carbon nanotubes (CNT) were irradiated in the longitudinal and perpendicular directions, with low energy carbon and helium ions in order to observe the formation of defects in the atomic structure. Analysis through Raman spectroscopy and scanning electron microscopy indicated bundle rupture and ion track formation on nanotube bundles. Aligned CNT presented a kind of defect comprising ravine formation and tube agglomeration on top of the substrate. The latter structure is possibly caused by static charge accumulation induced by the incoming ions. Fluence plays a role on the short range order. Higher fluence irradiation transforms CNT into amorphous carbon nanowires.

  7. Agglomeration defects on irradiated carbon nanotubes

    International Nuclear Information System (INIS)

    Aligned carbon nanotubes (CNT) were irradiated in the longitudinal and perpendicular directions, with low energy carbon and helium ions in order to observe the formation of defects in the atomic structure. Analysis through Raman spectroscopy and scanning electron microscopy indicated bundle rupture and ion track formation on nanotube bundles. Aligned CNT presented a kind of defect comprising ravine formation and tube agglomeration on top of the substrate. The latter structure is possibly caused by static charge accumulation induced by the incoming ions. Fluence plays a role on the short range order. Higher fluence irradiation transforms CNT into amorphous carbon nanowires.

  8. Models of agglomeration and glass transition

    CERN Document Server

    Kerner, Richard

    2007-01-01

    This book is for any physicist interested in new vistas in the domain of non-crystalline condensed matter, aperiodic and quasi-crystalline networks and especially glass physics and chemistry. Students with an elementary background in thermodynamics and statistical physics will find the book accessible. The physics of glasses is extensively covered, focusing on their thermal and mechanical properties, as well as various models leading to the formation of the glassy states of matter from overcooled liquids. The models of agglomeration and growth are also applied to describe the formation of quasicrystals, fullerenes and, in biology, to describe virus assembly pathways.

  9. The soundscape dynamics of human agglomeration

    CERN Document Server

    Ribeiro, H V; Lenzi, E K; Mendes, R S; Evangelista, L R

    2011-01-01

    We report a statistical analysis about people agglomeration soundscape. Specifically, we investigate the normalized sound amplitudes and intensities that emerge from people collective meetings. Our findings support the existence of nontrivial dynamics characterized by heavy tail distributions in the sound amplitudes, long-range correlations in the sound intensity and non-exponential distributions in the return interval distributions. Additionally, motivated by the time-dependent behavior present in the volatility/variance series, we compare the observational data with those obtained from a minimalist autoregressive stochastic model, a GARCH process, finding a good agreement.

  10. Analysis and synthesis of solutions for the agglomeration process modeling

    Science.gov (United States)

    Babuk, V. A.; Dolotkazin, I. N.; Nizyaev, A. A.

    2013-03-01

    The present work is devoted development of model of agglomerating process for propellants based on ammonium perchlorate (AP), ammonium dinitramide (ADN), HMX, inactive binder, and nanoaluminum. Generalization of experimental data, development of physical picture of agglomeration for listed propellants, development and analysis of mathematical models are carried out. Synthesis of models of various phenomena taking place at agglomeration implementation allows predicting of size and quantity, chemical composition, structure of forming agglomerates and its fraction in set of condensed combustion products. It became possible in many respects due to development of new model of agglomerating particle evolution on the surface of burning propellant. Obtained results correspond to available experimental data. It is supposed that analogical method based on analysis of mathematical models of particular phenomena and their synthesis will allow implementing of the agglomerating process modeling for other types of metalized solid propellants.

  11. Contributions to assessing the relative dimension of agglomeration theories

    Directory of Open Access Journals (Sweden)

    Ion POHOAŢĂ

    2013-04-01

    Full Text Available The aim of this paper is to structure, from a historical and spatial point of view, the existing specialists' concerns in developing theories about agglomeration. The complete and complex evaluation of agglomeration economies allows us to make important contributions to assessing the relative dimension of agglomeration theories, placing them within the research area of spatial economy and identifying them with the science of location and currently with the new economic geography (NEG.

  12. Agglomeration Economies in Semi-industrialized Countries: Evidence from Argentina

    OpenAIRE

    José A. Borello; Hernán Morhorlang; Diego Silva Failde

    2011-01-01

    This paper identifies and problematizes three gaps in the existing literature on agglomeration economies. First, it argues that the ontology of agglomeration economies, the way in which these economies are conceptualized, needs to be revised. Far from being something “in the air” for all firms to profit from them, tapping these economies requires a conscious and sustained effort from firms. Second, it takes issue with the idea that the functioning of agglomeration economies in semi-industrial...

  13. Trade and Agglomeration: the Strategic use of Protection Revisited

    OpenAIRE

    Thede, Susanna

    2007-01-01

    The purpose of this paper is to examine whether the strategic motive for protection present in trade and agglomeration models, in the so-called new economic geography framework, is sensitive to the standard assumption that there is a sole agglomeration industry. We first investigate unilateral trade policy effects on the international production and trade pattern and the resulting national welfare levels in a new economic geography model including several agglomeration industries. The strateg...

  14. The Structure of Agglomerates consisting of Polydisperse Particles

    OpenAIRE

    Eggersdorfer, M. L.; Pratsinis, S.E.

    2012-01-01

    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, k...

  15. Mechanisms for selective agglomeration of coals

    Energy Technology Data Exchange (ETDEWEB)

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

    1989-05-01

    The investigation of basic mechanisms which underlie various processes for cleaning coal by selective agglomeration with oil was continued. Further measurements were made of the heat of wetting or immersion of various types of coal and graphite. The heat of immersion is an indicator of hydrophobicity which appears to correlate with other indicators such as induction time. The heat of immersion of Upper Freeport coal was increased greatly by heating the material in air at 150{degree}C for 7 days. The increase appeared due to a combination of surface oxidation and other factors such as an increase in the heats of rehydration and swelling. Leaching Upper Freeport coal with boiling hydrochloric acid increased the heat of immersion at low pH. Further consideration was given to potential pyrite depressants and quebracho was selected for evaluation. The degree of suppression was observed to depend on the nature of the solids and the amount of agglomerant (heptane) as well as the concentration of quebracho. 12 figs.

  16. Effect of agglomeration on flowability of baby food powders.

    Science.gov (United States)

    Szulc, Karolina; Lenart, Andrzej

    2010-06-01

    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

  17. Agglomerates processing on in-flight images of granular products

    Science.gov (United States)

    Ros, Frederic; Guillaume, S.; Sevila, Francis

    1993-11-01

    Image analysis can be used to characterize granular populations in many processes in food industry or in agricultural engineering. Either global or individual parameters can be extracted from the image. However, granular products may appear agglomerate on the image, bringing biasing on individual parameters. Combining statistical and neural network technics enables the build of a system which can recognize if products are agglomerate or not. To process images after agglomerates detection, two approaches have been studied: the first is based on erosion, followed by conditional dilation with the original image; the second takes advantage of the graph's properties of the agglomerate's skeleton.

  18. Agglomeration of coal fines for premium fuel application

    International Nuclear Information System (INIS)

    This paper reports on fine coal in liquid suspension, which can be agglomerated in a number of ways. One of the oldest procedures involves the addition of electrolyte to the suspension to cause a reduction in the zeta potential and allow colliding particles to agglomerate. A second method involves the use of polymeric flocculants to bridge between particles. Both of these technologies are being used in the wastewater treatment plants for removal of fine waste particles from contaminated water. A third method involves the addition of a second immiscible liquid preferentially to wet the particles and cause adhesion by capillary interfacial forces. While the bonding forces in the first two methods are small and result in rather weak and voluminous agglomerates, the third method is postulated to produce more dense and much stronger agglomerates. In the case of fine coals, the carbonaceous constituents can be agglomerated and recovered from the aqueous suspension with many different coagulants. Inorganic or ash-forming constituents are also agglomerated along with the fine coal particles. As the froth floatation, agglomeration using coal and colloidal dust to effect a separation. Froth floatation, however, becomes less effective where extremely fine particles of cal must be treated or if there is considerable clay-size particle present. In contrast, there appears to be virtually no lower limit on the particle size suitable for agglomeration uses

  19. Fluid bed agglomeration with a narrow droplet size distribution

    NARCIS (Netherlands)

    Schaafsma, SH; Vonk, P; Kossen, NWF

    2000-01-01

    In the fluid bed agglomeration processes liquid distribution influences the agglomerate growth. We developed a new nozzle that produces uniform droplets, which allows droplets to be easily controlled in size independently of liquid- and airflow of the nozzle. It was found that the spray rate and the

  20. Agglomeration effects on countries' competitiveness and entrepreneurial performance

    OpenAIRE

    Páger, Balázs; Komlósi, Éva

    2015-01-01

    This paper aims to elaborate the role of agglomeration effects on countries' competitiveness and entrepreneurial performance. Our research contributes to the understanding of the relationship that exists between a country's urban system characterized by spatial agglomeration (concentration) or deglomeration (deconcentration) processes, and its competitiveness and entrepreneurial performance, respectively. Urbanization economies refer to considerable cost savings generated through the locating...

  1. Novel Binders and Methods for Agglomeration of Ore

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-09-30

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

  2. Effect of drug content and agglomerate size on tabletability and drug release characteristics of bromhexine hydrochloridetalc agglomerates prepared by crystallo-co-agglomeration.

    Science.gov (United States)

    Jadhav, Namdeo; Pawar, Atmaram; Paradkar, Anant

    2010-03-01

    The objective of the investigation was to study the effect of bromhexine hydrochloride (BXH) content and agglomerate size on mechanical, compressional and drug release properties of agglomerates prepared by crystallo-co-agglomeration (CCA). Studies on optimized batches of agglomerates (BXT1 and BXT2) prepared by CCA have showed adequate sphericity and strength required for efficient tabletting. Trend of strength reduction with a decrease in the size of agglomerates was noted for both batches, irrespective of drug loading. However, an increase in mean yield pressure (14.189 to 19.481) with an increase in size was observed for BXT2 having BXH-talc (1:15.7). Surprisingly, improvement in tensile strength was demonstrated by compacts prepared from BXT2, due to high BXH load, whereas BXT1, having a low amount of BXH (BXH-talc, 1:24), showed low tensile strength. Consequently, increased tensile strength was reflected in extended drug release from BXT2 compacts (Higuchi model, R(2) = 0.9506 to 0.9981). Thus, it can be concluded that interparticulate bridges formed by BXH and agglomerate size affect their mechanical, compressional and drug release properties. PMID:20228039

  3. Operational source receptor calculations for large agglomerations

    Science.gov (United States)

    Gauss, Michael; Shamsudheen, Semeena V.; Valdebenito, Alvaro; Pommier, Matthieu; Schulz, Michael

    2016-04-01

    For Air quality policy an important question is how much of the air pollution within an urbanized region can be attributed to local sources and how much of it is imported through long-range transport. This is critical information for a correct assessment of the effectiveness of potential emission measures. The ratio between indigenous and long-range transported air pollution for a given region depends on its geographic location, the size of its area, the strength and spatial distribution of emission sources, the time of the year, but also - very strongly - on the current meteorological conditions, which change from day to day and thus make it important to provide such calculations in near-real-time to support short-term legislation. Similarly, long-term analysis over longer periods (e.g. one year), or of specific air quality episodes in the past, can help to scientifically underpin multi-regional agreements and long-term legislation. Within the European MACC projects (Monitoring Atmospheric Composition and Climate) and the transition to the operational CAMS service (Copernicus Atmosphere Monitoring Service) the computationally efficient EMEP MSC-W air quality model has been applied with detailed emission data, comprehensive calculations of chemistry and microphysics, driven by high quality meteorological forecast data (up to 96-hour forecasts), to provide source-receptor calculations on a regular basis in forecast mode. In its current state, the product allows the user to choose among different regions and regulatory pollutants (e.g. ozone and PM) to assess the effectiveness of fictive emission reductions in air pollutant emissions that are implemented immediately, either within the agglomeration or outside. The effects are visualized as bar charts, showing resulting changes in air pollution levels within the agglomeration as a function of time (hourly resolution, 0 to 4 days into the future). The bar charts not only allow assessing the effects of emission

  4. Novel Binders and Methods for Agglomeration of Ore

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-03-31

    Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that 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.

  5. Novel Binders and Methods for Agglomeration of Ore

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-09-30

    Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that 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.

  6. Fragmentation and bond strength of airborne diesel soot agglomerates

    Directory of Open Access Journals (Sweden)

    Messerer Armin

    2008-06-01

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

  7. Colloidal agglomerates in tank sludge: Impact on waste processing

    International Nuclear Information System (INIS)

    'Insoluble colloidal sludges in hazardous waste streams such as tank wastes can pose serious problems for waste processing, interfering with retrieval, transport, separation, and solidification procedures. Properties of sediment layers and sludge suspensions such as slurry viscosities, sedimentation rates, and final sediment densities can vary by orders of magnitude depending on the particle types present, the degree to which the particles agglomerate or stick to each other, and on a wide range of processing parameters such as solution shear rates, pH, salt content, and temperature. The objectives of this work are to: (1) understand the factors controlling the nature and extent of colloidal agglomeration under expected waste processing conditions; (2) determine how agglomeration phenomena influence physical properties relevant to waste processing including rheology, sedimentation, and filtration; and (3) develop strategies for optimizing processing conditions via control of agglomeration phenomena. Insoluble colloidal sludges in hazardous waste streams such as tank wastes can pose serious problems for waste processing, interfering with retrieval, transport, separation, and solidification procedures. Properties of sediment layers and sludge suspensions such as slurry viscosities, sedimentation rates, and final sediment densities can vary by orders of magnitude depending on the particle types present, the degree to which the particles agglomerate or stick to each other, and on a wide range of processing parameters such as solution shear rates, pH, salt content, and temperature. The objectives of this work are to: (1) understand the factors controlling the nature and extent of colloidal agglomeration under expected waste processing conditions; (2) determine how agglomeration phenomena influence physical properties relevant to waste processing including rheology, sedimentation, and filtration; and (3) develop strategies for optimizing processing conditions via control

  8. Public Action and Innovationsupport Institutions in New Technological Agglomerations

    DEFF Research Database (Denmark)

    Borras, Susana; Bacaria, Jordi; Fernandez-Ribas, Andrea

    2002-01-01

    engaged in enhancing the technological capabilities and knowledge flow of the territory. Taking this consideration as a starting point, the article presents the dynamics of the technological agglomeration of the Vallès Occidental County, located within Catalonia, Spain. It has supplied information on the......In all industrial and technological agglomerations several types of public and semi-public actors coexist. The same happens with the levels of government. Consequently, the daily reality of agglomerations is characterized by a wide diversity of innovation-support institutions more or less actively...

  9. WP/084 Measuring Industry Agglomeration and Identifying the Driving Forces

    DEFF Research Database (Denmark)

    Howard, Emma; Tarp, Finn; Newman, Carol

    Understanding industry agglomeration and its driving forces is critical for the formulation of industrial policy in developing countries. Crucial to this process is the definition and measurement of agglomeration. We propose a new measure and examine what it reveals about the importance of...... transport costs, labour market pooling, and technology transfer for agglomeration processes. We contrast this analysis with insights from existing measures in the literature and find very different underlying stories at work. An exceptionally rich set of data from Vietnam makes us confident that our measure...

  10. Externalities, Floating Population and Spatial Agglomeration

    Institute of Scientific and Technical Information of China (English)

    Du Yu; Wang Chuansheng; Fan Jie

    2007-01-01

    With the further development of socialist market economy,the mobility of factor markets in China,especially the labor market.is strengthened.Extemalities interacts with the agglomeration of productive factors.Under the framework of new economic geographg this article presents a theoretical model involving the endogenous population density affected by urban externalities.Results show that the population density is more concentrated around the center because the degree and extent of interaction between individuals intensifies when the distance from the center decreases.When there are several extemalifies resonurces,the aggregation of externalities changes the configuration of spatial factor allocation.These results fit well with the empirical facts about the decreasing density of floating population along the cities of Guangzhou,Dongguan and Shenzhen in Guangdong Province which is situat d in the eastern coast of the Pearl River Delta.We find that under the impacts of externalities released from Hong Kong into the coast,floating population Was more concentrated around Shenzhen and Dongguan,which are more adjacent to Hong Kong compared with Guangzhou City.

  11. Evolution of Zipf's Law for Indian Urban Agglomerations vis-\\`{a}-vis Chinese Urban Agglomerations

    CERN Document Server

    Gangopadhyay, Kausik

    2012-01-01

    We investigate into the rank-size distributions of urban agglomerations for India between 1981 to 2011. The incidence of a power law tail is prominent. A relevant question persists regarding the evolution of the power tail coefficient. We have developed a methodology to meaningfully track the power law coefficient over time, when a country experience population growth. A relevant dynamic law, Gibrat's law, is empirically tested in this connection. We argue that these empirical findings for India goes in contrast with the findings in case of China, another country with population growth but monolithic political system.

  12. Amenability of Muzret bituminous coal to oil agglomeration

    Energy Technology Data Exchange (ETDEWEB)

    Sahinoglu, E.; Uslu, T. [Karadeniz Technical University, Department of Mining Engineering, 61080 Trabzon (Turkey)

    2008-12-15

    Laboratory scale agglomeration tests were undertaken to investigate the amenability of Muzret (Yusufeli-Artvin) bituminous coal to oil agglomeration. Kerosene was extensively used as oil in the tests. In addition, fuel oil, diesel oil, and hazelnut oil were also used in order to determine the effect of oil type. The effects of the parameters including coal content, kerosene content, agglomeration time, coal particle size, pH, oil type, and agitation rate, on the combustible matter recovery, ash reduction and pyritic sulphur reduction, were investigated. It was found that Muzret bituminous coal could be readily cleaned by oil agglomeration with substantial reductions in ash and pyritic sulphur content. Maximum combustible matter recovery, ash reduction and pyritic sulphur reduction were achieved to be 85.54%, 59.98%, and 85.17%, respectively. (author)

  13. Does firm agglomeration drive product innovation and renewal?.

    OpenAIRE

    De Beule, Filip; Van Beveren, Ilke

    2010-01-01

    This paper uses data from the Community Innovation Survey for Belgium to evaluate to what extent regional concentration (clusters) of firms, also known as agglomeration economies, may be enhancing for innovation. These agglomeration economies are positive externalities that benefit firms in various ways. For innovative performance, especially externalities related to knowledge spillovers matter. Knowledge spillovers or learning externalities typically emerge between firms that belong to the s...

  14. Differential labor mobility, agglomeration, and skill-biased migration policies

    OpenAIRE

    Russek, Stephan

    2009-01-01

    The paper analyzes the impact of skill-biased migration policies under the economics of agglomeration. It therefore develops an agglomeration model with two types of mobile worker who are heterogeneous and differ both within and between skill groups with respect to their migration propensity. On the one hand, the model reveals that the effectiveness of migration policies depends on the level on trade costs. On the other hand, it shows that increasing (reducing) political barriers to migration...

  15. Wet agglomeration of particles in a fluidized bed

    OpenAIRE

    Jimenez-Munguia, Maria-Teresa

    2007-01-01

    Particles agglomeration allows to modify their initial physical properties (size, shape, density, porosity) and to improve powder end-use properties like flowability, mechanical resistance and dispersibility, very important for pharmaceutics and food products. Fluidized bed agglomeration is obtained by spraying a liquid (solvent, binder solution) on fluidized particles to allow liquid bridges formation when wet particles collide. These bridges consolidate due to drying by the hot fluidizing a...

  16. Characterization of the geometrical properties of agglomerated aerosol particles

    International Nuclear Information System (INIS)

    A method for the absolute mass determination of agglomerated aerosol particles is presented. Based on this method it is possible to determine simultaneously and in situ mass, exposed surface and mobility diameter. From these measurements the fractal dimension of aerosol particles can be derived. For silver agglomerates produced by spark discharge it was found that they are bifractal. The fractal dimension was 3 in the free molecular regime and 1.9 in the transition regime. By variation of the gas mean free path it was shown that the region where the agglomerate structure changes from close-packed particle to low density agglomerates depends on the Knudsen number. In the free molecular regime the fractal dimension was not at all affected by any change of the generation conditions. Only sintering caused an increase in the density which was attributed to mass transport within the agglomerate. In the transition regime the fractal dimension remained constant with increasing monomer concentration and with increasing flow rate, but it increased with increasing pressure, increasing Ar:He ratio and with increasing sintering temperature. For sintering this effect was explained by the minimization of the surface free energy. It was found that the structure changing rate is proportional to the product of sintering temperature and residence time in the sintering oven. By carefully adjusting the temperature it is possible to produce agglomerates of a well defined structure. In desorption experiments of 136I from silver and carbon agglomerates it could be shown that the desorption behavior is different. It was found that the desorption enthalpy of iodine from graphite and silver particles were -142 kJ/mol and -184 kJ/mol, respectively. Moreover, it was demonstrated that the 136I attachment to particles is different for silver agglomerates with the same mobility, but different structures. (author) 41 figs., refs

  17. Defect agglomeration in ferroelectric ceramics under cyclic electric field

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The agglomeration of point defects in ferroelectric ceramics could be driven by repeated domain switching under cyclic electric field. The evolution equation of pore concentration under cyclic electric field is derived, with the help of a relation between the pore concentration and the extent of pore agglomeration. The results of the simulation agree quantitatively with the experimental data. An integrated framework about the mechanisms of electrically induced fatigue is proposed, which links the mechanisms at different scales.

  18. Marshallian Agglomeration Economies and Entrepreneurship: The Spanish Case

    OpenAIRE

    Fernandez, Roberto Dopeso

    2011-01-01

    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 by Marshall (1920). Also an index to measure the influence of small suppliers...

  19. Viewpoint: Agglomeration research in the age of disaggregation

    OpenAIRE

    William C. Strange

    2009-01-01

    This paper selectively reviews recent research on the economics of agglomeration. Theory offers a long list of forces that might explain the spatial concentration of economic activity. The increased availability of disaggregated data - by firm, by worker, and by geographical unit - presents opportunities to substantially advance the understanding of urban growth and industrial clustering. At present, however, there remains great uncertainty about the forces that produce agglomeration. This su...

  20. Industrial Performance, Agglomeration, and Foreign Manufacturing Investment in the UK

    OpenAIRE

    Nigel Driffield; Max Munday

    2000-01-01

    This paper examines the relationship between the comparative advantage of UK industries, and new inward investment into these industries. The paper demonstrates that the extent of foreign manufacturing investment in an industry, and the spatial agglomeration of that industry, are significant determinants of industry comparative advantage, thus providing evidence of agglomeration benefits to both domestic and foreign firms. The paper then shows that industry comparative advantage itself, toget...

  1. Using Raster Based Solutions to Identify Spatial Economic Agglomerations

    Directory of Open Access Journals (Sweden)

    Marian DARDALA

    2013-01-01

    Full Text Available The efficient economic activities incline to be concentrated in space, and therefore there is an increased attention over the forces of spatial economic agglomerations and the role of location in economic development. This paper proposes some solutions to automate the identification of spatial agglomerations and their intensities, function on the spatial distribution of items in the geographical areas. The software components developed to accomplish this task are Geographic Information Systems specific tools.

  2. Study on the Flow of Particle Agglomerates in Desulfurization Tower

    OpenAIRE

    Zheng Jian-Xiang; Xu Chun-Xing; Zhang Wei-Ling

    2014-01-01

    In order to study the flow feature of particle agglomerates in a desulfurization tower, a three-dimensional numerical simulation of the gas-solid two phase flow in the tower is carried out by use of the LES model and the cohesive particles kinetics theory. Based on the experimental model of the internal circulation multistage spray desulfurization tower, the simulation successfully captures the key flow features in a desulfurization tower, find that: agglomerates forming a stable fluidization...

  3. NOVEL BINDERS AND METHODS FOR AGGLOMERATION OF ORE

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-04-01

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

  4. Kinetic modelling of methane hydrate formation and agglomeration with and without anti-agglomerants from emulsion in pipelines

    OpenAIRE

    Pham, Trung-Kien; Melchuna, Aline; Cameirao, Ana; Herri, Jean-Michel; Duchet-Suchaux, Pierre; Glenat, Philippe

    2015-01-01

    Offshore systems mainly containing crude oil, natural gas and water operate at low temperature and high pressure which favour conditions for gas hydrate formation and agglomeration. Gas hydrate is a serious issue in flow assurance; it may cause many troubles, especially, plugging in oil and gas pipeline. This work is to intend to develop a kinetic model to predict gas hydrate formation, agglomeration and plugging in flowlines based on the experimental data obtained from Archimede Flowloop fro...

  5. A revisit to agglomerates of early-type Hipparcos stars

    Science.gov (United States)

    Caballero, J. A.; Dinis, L.

    2008-10-01

    % We study the spatial structure and sub-structure of regions rich in {Hipparcos} stars with blue B_T-V_T colours. These regions, which comprise large stellar complexes, OB associations, and young open clusters, are tracers of on-going star formation in the Galaxy. The DBSCAN (Density-Based Spatial Clustering of Applications with Noise) data clustering algorithm is used to look for spatial overdensities of early-type stars. Once an overdensity, ``agglomerate'', is identified, we carry out a data and bibliographic compilation of their star member candidates. The actual membership in agglomerate of each early-type star is studied based on its heliocentric distance, proper motion, and previous spectro-photometric information. We identify 35 agglomerates of early-type {Hipparcos} stars. Most of them are associated to previously known clusters and OB associations. The previously unknown P Puppis agglomerate is subject of a dedicated study with Virtual Observatory tools. It is actually a new, nearby, young open cluster (d ˜ 470 pc, age ˜ 20 Ma) with a clear radial density gradient. We list P Puppis and other six agglomerates (including NGC 2451 A, vdBH 23, and Trumpler 10) as new sites for substellar searches because of their youth, closeness, and spatial density. We investigate in detail the sub-structure in the Orion, CMa-Pup and Pup-Vel OB complexes (``super-agglomerates''). We confirm or discover some stellar overdensities in the Orion complex, like the 25 Ori group, the Horsehead region (including the σ Orionis cluster), and the η Orionis agglomerate. Finally, we derive accurate parallactic distances to the Pleiades, NGC 2451 A, and IC 2391, describe several field early-type stars at d < 200 pc, and discuss the incompleteness of our search.

  6. Novel Binders and Methods for Agglomeration of Ore

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-12-31

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

  7. Crystallo-co-agglomeration: A novel particle engineering technique

    Directory of Open Access Journals (Sweden)

    Paradkar Anant

    2010-01-01

    Full Text Available Crystallo-co-agglomeration (CCA is a novel particle engineering/design technique developed by Kadam et al, to overcome the limitations of spherical crystallization (SC. Basically, it′s single step process used for size enlargement of single, two or more, small dose or large dose drugs, in combination with or without diluent. The process of CCA involves simultaneous crystallization and agglomeration of drug/s with/without excipients/s from good solvent and/or bridging liquid by addition of a non-solvent. Till date CCA has been applied for spherical agglomeration of talc, bromhexine hydrochloride-talc, ibuprofen-talc, ibuprofen-paracetamol, and naproxen-starch. The spherical agglomerates obtained by CCA can be used as intact beads (encapsulated spansules or directly compressible tablet intermediates having satisfactory micromeritic (flowability, mechanical (friability, crushing, compressional (compressibility, compactibility, and drug release properties. Modified drug release from agglomerates and compacts thereof can be achieved using suitable polymer composition in the process design. Thus, it can be concluded that, CCA is a simple and cost effective process, which can be tailor-made for particle design of all majority of drugs and combinations thereof.

  8. Theranostic potential of gold nanoparticle-protein agglomerates

    Science.gov (United States)

    Sanpui, Pallab; Paul, Anumita; Chattopadhyay, Arun

    2015-11-01

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

  9. Advanced physical fine coal cleaning spherical agglomeration. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1990-09-01

    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.

  10. A Critical Study of Agglomerated Multigrid Methods for Diffusion

    Science.gov (United States)

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

    2011-01-01

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

  11. Reconstruction of Industrial Location in View of Industrial Agglomeration

    Institute of Scientific and Technical Information of China (English)

    ZHU Huayou; DING Sibao

    2006-01-01

    The Industrial Agglomeration Theory has been evolving all the time. The study on the industrial location has become the focus of the massive theoretical location problems about agglomeration since the 1970s. The authors here analyze the evolution and the characteristics of the Industrial Agglomeration Theory and study its effect on the reconstruction of industrial location. The study suggests that the new idea of reconstruction of industrial location is to cultivate regional innovative system. On this basis, the authors analyze two cases of old industrial bases on their construction-Tiexi Industrial District in Shenyang City and Changchun Industrial Economic Development Zone. Finally, the authors put forward some suggestions that should be regarded, which include: 1) to combine industrial location reconstruction and enterprises' inner reform; 2) to speed up adjustment of resources and opening to the world; 3) to combine government mechanism with the market mechanism properly.

  12. Ultrasonic de-agglomeration of barium titanate powder.

    Science.gov (United States)

    Marković, S; Mitrić, M; Starcević, G; Uskoković, D

    2008-01-01

    BaTiO3 (BT) powder, with average particle size of 1.4 microm, was synthesized by solid-state reaction. A high-intensity ultrasound irradiation (ultrasonication) was used to de-agglomerate micro-sized powder to nano-sized one. The crystal structure, crystallite size, morphology, particle size, particle size distribution, and specific surface area of the BT powder de-agglomerated for different ultrasonication times (0, 10, 60, and 180 min) were determined. It was found that the particles size of the BT powder was influenced by ultrasonic treatment, while its tetragonal structure was maintained. Therefore, ultrasonic irradiation can be proposed as an environmental-friendly, economical, and effective tool for the de-agglomeration of barium titanate powders. PMID:17845864

  13. Basic principles and mechanisms of selective oil agglomeration

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-01-01

    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.

  14. Spray drying engineering: particle stickiness in relation with agglomeration

    OpenAIRE

    Gianfrancesco, Alessandro

    2009-01-01

    Food instant powders like milk, soups, juices, coffee, are usually produced by spray drying followed by a further step of agglomeration to get larger particles (from 50-100 μm to 250-500 μm) with a narrow size distribution and modified structure (porosity) to obtain good handling and instant properties (wettability, dispersability, solubility). Agglomeration of spray dried powders is performed either outside or inside the drying chamber in a fluid bed, or by return of dry fines into the chamb...

  15. Basic principles and mechanisms of selective oil agglomeration

    Energy Technology Data Exchange (ETDEWEB)

    Wheelock, T.D.

    1994-07-01

    The overall objective of this work is to determine the important principles and basic mechanisms which underlie various selective oil agglomeration processes for beneficiating fine-size coal in order to facilitate the technical development and application of such processes to various types of coal. The recent work described herein has involved a more detailed study of the effects of mild oxidation on the surface properties of different types of coal and the relationship between the agglomerability of oxidized coals and their surface properties. In addition, the work has involved developing more effective means for separating coal and pyrite by finding and applying selective depressants for pyrite.

  16. A revisit to agglomerates of early-type Hipparcos stars

    CERN Document Server

    Caballero, J A

    2008-01-01

    We study the spatial structure and sub-structure of regions rich in Hipparcos stars with blue B_T-V_T colours. These regions, which comprise large stellar complexes, OB associations, and young open clusters, are tracers of on-going star formation in the Galaxy. The DBSCAN (Density-Based Spatial Clustering of Applications with Noise) data clustering algorithm is used to look for spatial overdensities of early-type stars. Once an overdensity, "agglomerate", is identified, we carry out a data and bibliographic compilation of their star member candidates. The actual membership in agglomerate of each early-type star is studied based on its heliocentric distance, proper motion, and previous spectro-photometric information. We identify 35 agglomerates of early-type Hipparcos stars. Most of them are associated to previously known clusters and OB associations. The previously unknown P Puppis agglomerate is subject of a dedicated study with Virtual Observatory tools. It is actually a new, nearby, young open cluster (d ...

  17. Experimental studies of the gravitational agglomeration of aerosols. Pt. 2

    International Nuclear Information System (INIS)

    Experiments have been performed to investigate the influence of gravitational agglomeration as an aerosol depletion process in a small containment vessel. The resulting data will aid in the development of computer codes that describe aerosol transport processes following severe reactor accidents. (author)

  18. Basic principles and mechanisms of selective oil agglomeration

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-04-01

    The overall objective is to determine the basic principles and mechanisms which underlie a number of selective oil agglomeration processes that have been proposed for beneficiating fine-size coal. An understanding of the basic principles and mechanisms will greatly facilitate technical development and application of such processes to various types of coal. 5 refs., 16 figs., 2 tabs.

  19. Quantitative characterization of nanoparticle agglomeration within biological media

    Energy Technology Data Exchange (ETDEWEB)

    Hondow, Nicole, E-mail: n.hondow@leeds.ac.uk; Brydson, Rik [University of Leeds, Institute for Materials Research (United Kingdom); Wang, Peiyi [University of Leeds, Institute of Molecular and Cellular Biology (United Kingdom); Holton, Mark D.; Brown, M. Rowan; Rees, Paul; Summers, Huw D. [Swansea University, Centre for Nanohealth, College of Engineering (United Kingdom); Brown, Andy [University of Leeds, Institute for Materials Research (United Kingdom)

    2012-07-15

    Quantitative analysis of nanoparticle dispersion state within biological media is essential to understanding cellular uptake and the roles of diffusion, sedimentation, and endocytosis in determining nanoparticle dose. The dispersion of polymer-coated CdTe/ZnS quantum dots in water and cell growth medium with and without fetal bovine serum was analyzed by transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. Characterization by TEM of samples prepared by plunge freezing the blotted solutions into liquid ethane was sensitive to the dispersion state of the quantum dots and enabled measurement of agglomerate size distributions even in the presence of serum proteins where DLS failed. In addition, TEM showed a reduced packing fraction of quantum dots per agglomerate when dispersed in biological media and serum compared to just water, highlighting the effect of interactions between the media, serum proteins, and the quantum dots. The identification of a heterogeneous distribution of quantum dots and quantum dot agglomerates in cell growth medium and serum by TEM will enable correlation with the previously reported optical metrology of in vitro cellular uptake of this quantum dot dispersion. In this paper, we present a comparative study of TEM and DLS and show that plunge-freeze TEM provides a robust assessment of nanoparticle agglomeration state.

  20. Effect of polymers on crystallo-co-agglomeration of ibuprofen-paracetamol: Factorial design

    Directory of Open Access Journals (Sweden)

    Pawar A

    2007-01-01

    Full Text Available The purpose of this research was to study the effect of concentration of polyethylene glycol and ethyl cellulose on the properties of agglomerates of ibuprofen-paracetamol obtained by crystallo-co-agglomeration technique. The process of crystallo-co-agglomeration involved recrystallization of ibuprofen and its simultaneous agglomeration with paracetamol in presence polymers. The effect of combination of polyethylene glycol and ethylcellulose was studied by 2 2 factorial design. Ibuprofen content of the agglomerate increased with increase in ethyl cellulose while paracetamol content was decreased with increase in polyethylene glycol. Differential scanning calorimetry thermograms of agglomerates showed the unchanged endotherm for ibuprofen melting, whereas paracetamol endotherm was diffused with low enthalpy. The agglomerates were spherical but increase in polyethylene glycol caused its deformation. Agglomerates containing ethylcellulose with polyethylene glycol have higher resistance for fragmentation, modulus of elasticity but impart high tensile strength.

  1. Formation of the economic efficiency of industrial Dnipropetrovsk and Dniprodzerzhynsk agglomeration. O. V. Gladkyj

    OpenAIRE

    Gladkyj O.V.

    2009-01-01

    The features are opened of the formation of polycentric economic efficiency of industrial agglomerations. An assessment of the effectiveness of industrial Dnipropetrovsk Dneprodzerzhinskoy agglomeration and recommendations on optimization of its functional structure.

  2. Formation of the economic efficiency of industrial Dnipropetrovsk and Dniprodzerzhynsk agglomeration. O. V. Gladkyj

    Directory of Open Access Journals (Sweden)

    Gladkyj O.V.

    2009-08-01

    Full Text Available The features are opened of the formation of polycentric economic efficiency of industrial agglomerations. An assessment of the effectiveness of industrial Dnipropetrovsk Dneprodzerzhinskoy agglomeration and recommendations on optimization of its functional structure.

  3. Effect of polymers on crystallo-co-agglomeration of ibuprofen-paracetamol: Factorial design

    OpenAIRE

    Pawar A; Paradkar A; Kadam S; Mahadik K

    2007-01-01

    The purpose of this research was to study the effect of concentration of polyethylene glycol and ethyl cellulose on the properties of agglomerates of ibuprofen-paracetamol obtained by crystallo-co-agglomeration technique. The process of crystallo-co-agglomeration involved recrystallization of ibuprofen and its simultaneous agglomeration with paracetamol in presence polymers. The effect of combination of polyethylene glycol and ethylcellulose was studied by 2 2 factorial design. Ibuprofen con...

  4. AGGLOMERATION AND RADIATION EFFECT OF THE PULL OF URBANIZATION

    Institute of Scientific and Technical Information of China (English)

    QI Jin-li

    2003-01-01

    In order to explore the train of thought for China's urbanizing development and coordinated rural eco-nomic development, and to find good ways of solving rural problems through urbanization, this paper absorbs the push-and-pull forces theory and the systematic dynamic theory in the traditional population migration theories, views urbanization as a dynamic system, makes research on the push-and-pull mechanism of urbanization. The pull ingpower of urbanization is analyzed according to two aspects, the agglomeration effect and the radiation effect of cities. The agglomeration effect provides continuous propelling force for urbanization, and the radiation effect furtheraccelerates the urbanization process by pushing forward the development of rural economy. Of course, the slow de-velopment of urbanization can result in the hindrance to rural economic development.

  5. Bifurcation theory for hexagonal agglomeration in economic geography

    CERN Document Server

    Ikeda, Kiyohiro

    2014-01-01

    This book contributes to an understanding of how bifurcation theory adapts to the analysis of economic geography. It is easily accessible not only to mathematicians and economists, but also to upper-level undergraduate and graduate students who are interested in nonlinear mathematics. The self-organization of hexagonal agglomeration patterns of industrial regions was first predicted by the central place theory in economic geography based on investigations of southern Germany. The emergence of hexagonal agglomeration in economic geography models was envisaged by Krugman. In this book, after a brief introduction of central place theory and new economic geography, the missing link between them is discovered by elucidating the mechanism of the evolution of bifurcating hexagonal patterns. Pattern formation by such bifurcation is a well-studied topic in nonlinear mathematics, and group-theoretic bifurcation analysis is a well-developed theoretical tool. A finite hexagonal lattice is used to express uniformly distri...

  6. Experimental study of fluidized bed agglomeration of acerola powder

    Directory of Open Access Journals (Sweden)

    G. C. Dacanal

    2008-03-01

    Full Text Available The aim of this work was to study the main effects of acerola powder on fluidized bed agglomeration. A 2(4-1 fractional factoring design was used to evaluate the main operating conditions (fluidizing air temperature, fluidizing air velocity, atomizing air flow and height of nozzle in the bed. The mechanical and physicochemical product changes were determined by analysis of particle diameter, moisture content, wetting time and bed porosity. The particle enlargement by agglomeration occurred when the relative humidity in the bed increased and, thus, the moisture of the product increased. However, the excessive increase in relative humidity resulted in a decrease in yield, caused by caking and product incrustation. The consolidation of small granules resulted in an increase in the instant properties, decreasing the wetting time and increasing the solubility in a short period of agitation.

  7. Study on the Flow of Particle Agglomerates in Desulfurization Tower

    Directory of Open Access Journals (Sweden)

    Zheng Jian-Xiang

    2014-01-01

    Full Text Available In order to study the flow feature of particle agglomerates in a desulfurization tower, a three-dimensional numerical simulation of the gas-solid two phase flow in the tower is carried out by use of the LES model and the cohesive particles kinetics theory. Based on the experimental model of the internal circulation multistage spray desulfurization tower, the simulation successfully captures the key flow features in a desulfurization tower, find that: agglomerates forming a stable fluidization and stable internal circulation in the tower, present a typical ring-nuclear flow distribution trend. And the effects of the inlet gas velocity and inlet mass flux to the internal circulation are also analyzed.

  8. Flocculation, hydrophobic agglomeration and filtration of ultrafine coal

    Science.gov (United States)

    Yu, Zhimin

    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

  9. Engineering development of selective agglomeration: Trace element removal study

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-01

    Southern Company Services, Inc., (SCS) was contracted in 1989 by the US Department of Energy (DOE) to develop a commercially acceptable selective agglomeration technology to enhance the use of high-sulfur coals by 1993. The project scope involved development of a bench-scale process and components, as well as the design, testing, and evaluation of a proof-of-concept (POC) facility. To that end, a two-ton-per-hour facility was constructed and tested near Wilsonville, Alabama. Although it was not the primary focus of the test program, SCS also measured the ability of selective agglomeration to remove trace elements from coal. This document describes the results of that program.

  10. Potential pyrite depressants for use in oil agglomeration of fine-size coal

    Energy Technology Data Exchange (ETDEWEB)

    Drzymala, J.; Wheelock, T.D. (Iowa State University, Ames, IA (USA). Ames Laboratory and Chemical Engineering Dept.)

    1992-01-01

    Potential pyrite depressants for use in coal beneficiation involving oil agglomeration were identified. Particles of sulphurized pyrite, chosen because it was readily agglomerated, were treated with the potential depressants prior to agglomeration with heptane. The following suppressed the agglomeration of sulphurized pyrite, ferric chloride; potassium monopersulphate; hydrogen peroxide; ferrous sulphate; sodium dithionite; sodium thiosulphate; sodium sulphide; titanous chloride; pyrogallol; quebracho; and milk whey. The separation of Upper Freeport coal and sulphurized pyrite by agglomeration with heptane was greatly improved by treatment with ferric chloride. 20 refs., 8 figs., 1 tab.

  11. Computer simulation of aerosol dynamics with a unified agglomeration kernel

    International Nuclear Information System (INIS)

    Aerosol dynamics have been simulated with the computer code CONTAIN using a modified agglomeration kernel. The time (t) evolution of the size distribution (nk(t)) and the suspended mass concentration of particles of size index k was calculated for both the new kernel and the standard superposition kernel. In addition, the fractal nature of the particle geometry has been accounted for and the implications on the distributions are discussed. (author)

  12. Rural-to-urban migration, human capital, and agglomeration

    OpenAIRE

    Stark, Oded; Fan, C. Simon

    2007-01-01

    A new general-equilibrium model that links together rural-to-urban migration, the externality effect of the average level of human capital, and agglomeration economies shows that in developing countries, unrestricted rural-to-urban migration reduces the average income of both rural and urban dwellers in equilibrium. Various measures aimed at curtailing rural-to-urban migration by unskilled workers can lead to a Pareto improvement for both the urban and rural dwellers. In addition, the governm...

  13. Heterogenous skills and homogeneous land: segmentation and agglomeration

    OpenAIRE

    Wrede, Matthias

    2009-01-01

    This paper analyzes the impact of skill heterogeneity on regional patterns of production and housing in the presence of pecuniary externalities within a general equilibrium framework assuming monopolistic competition at intermediate good markets. It shows that the interplay of heterogenous skills and relatively homogeneous land demand triggers skill segmentation and agglomeration. The core region, being more attractive to high skilled workers, has a disproportionately large share of productio...

  14. Heterogeneous Skills and Homogeneous Land: Segmentation and Agglomeration

    OpenAIRE

    Wrede, Matthias

    2010-01-01

    This paper analyzes the impact of skill heterogeneity on regional patterns of production and housing in the presence of pecuniary externalities within a general-equilibrium framework assuming monopolistic competition at intermediate good markets. It shows that the interplay of heterogeneous skills and relatively homogeneous land demand triggers skill segmentation and agglomeration. The core region, being more attractive to high skilled workers, has a disproportionately large share of producti...

  15. Industry Relatedness, Agglomeration Externalities and Firm Survival in China

    OpenAIRE

    Canfei He; Qi Guo; David Rigby

    2015-01-01

    The importance of agglomeration externalities for economic activities is widely recognized. Recent developments highlight the importance of industry relatedness to the performance of firms, industries and regions. This study explores the determinants of firm survival in China and tests the significance of industry relatedness using firm-level data over the period 1999-2007. Industry relatedness is developed from the co-occurrence analysis of paired industries. Results based on Cox regression ...

  16. Acquisition of skills, education subsidies, and agglomeration of firms

    OpenAIRE

    Toulemonde, Eric

    2003-01-01

    An analytically solvable model of new economic geography is developed. Acquisition of skills is costly for workers but it allows them to earn wages that are larger than those of the unskilled. Moreover, skills acquisition can be subsidized by a regional government. For large transport costs, firms spread more or less evenly between regions, their precise location being determined by the level of education subsidies. For low transport costs, firms agglomerate in one region. We also identify eq...

  17. Do Agglomeration Economies Exist in the Hospital Services Industry

    OpenAIRE

    Laurie J. Bates; Rexford E. Santerre

    2005-01-01

    Given the importance of knowledge flows and the continued emphasis on face-to-face encounters especially for medical care, close proximity of hospitals may be essential for the efficient delivery of medical care. That is, hospital productivity might be greater where hospitals cluster and allow knowledge to more easily and quickly disperse among personnel in the various organizations. To add to the understanding about agglomeration economies in the hospital services sector, this study analyzes...

  18. Spatial costs in a monocentric city (and implications for agglomeration)

    OpenAIRE

    Hugh B. Wenban-Smith

    2009-01-01

    Using water supply as a model for a wider range of infrastructure services, the effect of a negative exponential density gradient on distribution costs is investigated for four monocentric urban development scenarios: (a) Densification; (b) Dispersion; (c) Suburbanisation; and (d) Constant density. It is shown that economies of scale in production can be outweighed by diseconomies in distribution in cases (b) and (c), suggesting that the agglomeration benefits of infrastructure cannot be take...

  19. Reynolds number effects on particle agglomeration in turbulent channel flow

    OpenAIRE

    M Afkhami; A. Hassanpour; Fairweather, M.; Njobuenwu, DO

    2014-01-01

    The work described in this paper employs large eddy simulation and a discrete element method to study particle-laden flows, including particle dispersion and agglomeration, in a horizontal channel. The particle-particle interaction model is based on the Hertz- Mindlin approach with Johnson-Kendall-Roberts cohesion to allow the simulation of Van der Waals forces in a dry air flow. The influence of different flow Reynolds numbers, and therefore the impact of turbulence, on particle agglomeratio...

  20. Estimating agglomeration economies in Spain: evidence from geographically disaggregated data

    OpenAIRE

    Dapena, Alberto Díaz; Vázquez, Esteban Fernández; Morollón, Fernando Rubiera

    2015-01-01

    In this paper we estimate agglomeration economies in Spain in 2009 basing on Ciccone?s (2002) model, which explains average labor productivity in one spatial unit on employment density and other controls. The novelty of our analysis is that the empirical model is estimated at a highly disaggregated spatial scale, oppositely to the convention of taking as unit of analysis NUTS-2 or NUTS-3 regions. Recent contributions to New Economic Geography (NEG) base their theoretical analysis on geographi...

  1. Informality and agglomeration economies: in search of the missing links

    OpenAIRE

    Ana Isabel Moreno Monroy; Michiel Gerritse

    2011-01-01

    The informal sector absorbs on average 50% of employment in developing countries. However, it has not been considered in New Economic Geography (NEG) models that try to explain urbanization and agglomeration in developing countries. In a first attempt to bridge this gap, we develop a NEG model that incorporates the informal sector. Empirical evidence shows that the informal sector is mainly composed of relatively small firms that are unskilled labor intensive, face capital restrictions and th...

  2. Reversible or not? Distinguishing agglomeration and aggregation at the nanoscale.

    Science.gov (United States)

    Sokolov, Stanislav V; Tschulik, Kristina; Batchelor-McAuley, Christopher; Jurkschat, Kerstin; Compton, Richard G

    2015-10-01

    Nanoparticles are prone to clustering either via aggregation (irreversible) or agglomeration (reversible) processes. It is exceedingly difficult to distinguish the two via conventional techniques such as dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), or electron microscopy imaging (scanning electron microscopy (SEM), transmission electron microscopy (TEM)) as such techniques only generally confirm the presence of large particle clusters. Herein we develop a joint approach to tackle the issue of distinguishing between nanoparticle aggregation vs agglomeration by characterizing a colloidal system of Ag NPs using DLS, NTA, SEM imaging and the electrochemical nanoimpacts technique. In contrast to the conventional techniques which all reveal the presence of large clusters of particles, electrochemical nanoimpacts provide information regarding individual nanoparticles in the solution phase and reveal the presence of small nanoparticles (detection of small nanoparticles in high ionic strength media evidence the clustering to be a reversible process. As a result it is concluded that agglomeration rather than irreversible aggregation takes place. This observation is of general importance for all colloids as it provides a feasible analysis technique for a wide range of systems with an ability to distinguish subtly different processes. PMID:26352558

  3. One-step aerosol synthesis of nanoparticle agglomerate films: simulation of film porosity and thickness

    International Nuclear Information System (INIS)

    A method is described for designing nanoparticle agglomerate films with desired film porosity and film thickness. Nanoparticle agglomerates generated in aerosol reactors can be directly deposited on substrates to form uniform porous films in one step, a significant advance over existing technologies. The effect of agglomerate morphology and deposition mechanism on film porosity and thickness are discussed. Film porosity was calculated for a given number and size of primary particles that compose the agglomerates, and fractal dimension. Agglomerate transport was described by the Langevin equation of motion. Deposition enhancing forces such as thermophoresis are incorporated in the model. The method was validated for single spherical particles using previous theoretical studies. An S-shape film porosity dependence on the particle Peclet number typical for spherical particles was also observed for agglomerates, but films formed from agglomerates had much higher porosities than films from spherical particles. Predicted film porosities compared well with measurements reported in the literature. Film porosities increased with the number of primary particles that compose an agglomerate and higher fractal dimension agglomerates resulted in denser films. Film thickness as a function of agglomerate deposition time was calculated from the agglomerate deposition flux in the presence of thermophoresis. The calculated film thickness was in good agreement with measured literature values. Thermophoresis can be used to reduce deposition time without affecting the film porosity

  4. One-step aerosol synthesis of nanoparticle agglomerate films: simulation of film porosity and thickness

    Energy Technology Data Exchange (ETDEWEB)

    Maedler, Lutz; Lall, Anshuman A; Friedlander, Sheldon K [Nanoparticle Technology and Air Quality Laboratory, Department of Chemical and Biomolecular Engineering, University of California, Los Angeles (UCLA), 5531-G Boelter Hall, Los Angeles, CA 90095 (United States)

    2006-10-14

    A method is described for designing nanoparticle agglomerate films with desired film porosity and film thickness. Nanoparticle agglomerates generated in aerosol reactors can be directly deposited on substrates to form uniform porous films in one step, a significant advance over existing technologies. The effect of agglomerate morphology and deposition mechanism on film porosity and thickness are discussed. Film porosity was calculated for a given number and size of primary particles that compose the agglomerates, and fractal dimension. Agglomerate transport was described by the Langevin equation of motion. Deposition enhancing forces such as thermophoresis are incorporated in the model. The method was validated for single spherical particles using previous theoretical studies. An S-shape film porosity dependence on the particle Peclet number typical for spherical particles was also observed for agglomerates, but films formed from agglomerates had much higher porosities than films from spherical particles. Predicted film porosities compared well with measurements reported in the literature. Film porosities increased with the number of primary particles that compose an agglomerate and higher fractal dimension agglomerates resulted in denser films. Film thickness as a function of agglomerate deposition time was calculated from the agglomerate deposition flux in the presence of thermophoresis. The calculated film thickness was in good agreement with measured literature values. Thermophoresis can be used to reduce deposition time without affecting the film porosity.

  5. Analysis on the Spatial-Temporal Dynamics of Financial Agglomeration with Markov Chain Approach in China

    Directory of Open Access Journals (Sweden)

    Weimin Chen

    2014-01-01

    Full Text Available The standard approach to studying financial industrial agglomeration is to construct measures of the degree of agglomeration within financial industry. But such measures often fail to exploit the convergence or divergence of financial agglomeration. In this paper, we apply Markov chain approach to diagnose the convergence of financial agglomeration in China based on the location quotient coefficients across the provincial regions over 1993–2011. The estimation of Markov transition probability matrix offers more detailed insights into the mechanics of financial agglomeration evolution process in China during the research period. The results show that the spatial evolution of financial agglomeration changes faster in the period of 2003–2011 than that in the period of 1993–2002. Furthermore, there exists a very uneven financial development patterns, but there is regional convergence for financial agglomeration in China.

  6. Insights into methane hydrate formation, agglomeration, and dissociation in water + diesel oil dispersed system

    International Nuclear Information System (INIS)

    Highlights: • Hydrate agglomeration occurs at initial hydrate formation or under shutting down stages. • The agglomeration of hydrate is inhibited and dispersed with the action of anti-agglomerants. • The appearance of surface water may cause the agglomeration of hydrate during hydrate dissociation. • A mechanism was proposed to describe hydrate dissociation from water in oil dispersed system. - Abstract: Methane hydrate formation and dissociation in (5 vol% water + 95 vol% diesel oil) dispersed system containing a combined anti-agglomerant were experimentally studied using a high pressure autoclave installed with particle video microscope and focused beam reflectance measurement probes. The agglomeration of hydrate was found to occur at the initial hydrate formation stage. With the continuous formation of hydrate, the agglomeration of hydrate will be inhibited and hydrate was dispersed with the action of the anti-agglomerant. The agglomeration of hydrate also occurs when the hydrate containing fluid is under static state for a certain time. Larger hydrate particles attached by gas bubble with grape-like shape were found during hydrate dissociation. The dissociated surface water would contact with un-dissociated hydrate and accumulate to larger water/hydrate particles may be the reason that causes the agglomeration during initial hydrate dissociation process. A mechanism was proposed to describe hydrate dissociation from water in oil dispersed system

  7. Intra-metropolitan migration in the Warsaw agglomeration.

    Science.gov (United States)

    Rykiel, Z

    1984-01-01

    "Two questions of intra-metropolitan migration are analyzed in the paper, intra-metropolitan hierarchy and intra-metropolitan spatial barriers. The former embraces four detailed questions: ranking of centers; spatial pattern of hierarchical subordination; degree of unequivocalness of the subordinations, or degree of dominance; and degree of hierarchicality of interrelationships. Two specialties of the Warsaw [Poland] agglomeration are discussed, the influence of the present crisis, and the administrative restrictions to migration to the city, or the spatial barriers. Social connotations of the latter are also presented." PMID:12312885

  8. Agglomeration techniques for the production of spheres for packed beds

    International Nuclear Information System (INIS)

    One attractive fusion-breeder-blanket design features a lithium bearing ceramic in the form of spheres packed into a random array. The spheres have diameters of 3 mm and 0.3 mm. This report surveys techniques used to produce ceramic spheres on an industrial scale. The methods examined include tumbling and mixing granulation, extrusion, briquetting and pelletizing. It is concluded that the required quantities of 0.3 mm diameter spheres can be produced by the tumbling agglomeration of a feed powder. The 3 mm diameter spheres will be made using a process of extrusion, chopping and rolling

  9. Agglomeration and Deposition Behaviour of Solid Recovered Fuel

    DEFF Research Database (Denmark)

    Pedersen, Morten Nedergaard; Jensen, Peter Arendt; Hjuler, Klaus;

    2016-01-01

    formation, or accumulation of impurities. The combustion of polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), wood, and SRF were studied in a rotary drum furnace. The combustion was recorded on a camera (60 frames per second), so that any agglomeration or deposition of fuel or ash...... a careful combustion control. The ash from SRF or wood does not pose a significant risk of melting and deposits at temperatures up to 1000 °C, but the presence of glass impurities in some SRF may limit operation temperatures to 900 °C as a result of ash melting....

  10. Influences of seed size and number on agglomeration in synthetic Bayer liquors

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bin; ZHOU Ke-chao; CHEN Qi-yuan

    2006-01-01

    By means of Malvern laser particle size analyzer and scanning electron microscopy, the influences of seed size and number on agglomeration in Bayer process were investigated. Agglomeration is almost finished in 8 h,seeds, below 5 μm, especially below 2 μm, gather together rapidly and almost disappear in 8 h. In the same supersaturation of aluminate solution and seed size, the smaller the number of seed is, the bigger the degree of agglomeration is. With the same primary number of seed, the agglomeration of larger seed is superior to that of small seed,and the agglomeration does not happen among the coarse seeds. The agglomeration mainly happens among fine particles, and the combinations among the fine particles are unconsolidated.

  11. Large Agglomerations and Economic Growth in Urban India: An Application of Panel Data Model

    OpenAIRE

    Tripathi, Sabyasachi

    2012-01-01

    This paper investigates the impact of urban agglomeration on urban economic growth, using static and dynamic panel data approach, based on data of 52 large cities in India for the period 2000 to 2009. The results shows that agglomeration has a strong positive effect on urban economic growth and support the “Williamson hypothesis” that agglomeration increases economic growth only up to certain level of economic development. The critical level per-capita city income is estimated about Rs. 37049...

  12. HYDROPHOBIC AGGLOMERATION OF MINERAL FINES IN AQUEOUS SUSPENSIONS AND ITS APPLICATION IN FLOTATION: A REVIEW

    OpenAIRE

    BINGQIAO YANG; SHAOXIAN SONG

    2014-01-01

    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, shea...

  13. Study on the Policy Factors of Innovative Talents Agglomeration in Jiangsu Province based on Data Analysis

    OpenAIRE

    Li Wenfei; Li Min

    2016-01-01

    Innovative talent is the key factor to promote the development of innovative economy and realize innovative drive in Jiangsu Province. Innovative talent agglomeration can fully play the effect of innovative talents through the agglomeration efficiency. Among many factors that affect the agglomeration of innovative talents, the guiding role of government policy factors is becoming more and more important. Based on the survey of domestic and foreign literature, through questionnaire survey, thi...

  14. Impact of agglomeration on the regional growth of Latin American countries

    OpenAIRE

    Rosero, Grace Carolina Guevara

    2015-01-01

    Theoretical approaches have been developed to examine the effect of agglomeration on growth. However, the understanding of the mechanisms of agglomeration in developing countries remains unaddressed. This paper aims to give empirical evidence of the role of agglomeration on the growth of Latin American regions. The study of the subcontinent is crucial because of the evidence of a rapid pace of urbanization process. Using a database with information of 162 regions of 8 Latin American countries...

  15. Do urban social enterprises benefit from agglomeration? Evidence from four UK cities

    OpenAIRE

    Pinch, Steven; Sunley, Peter

    2015-01-01

    Pinch S. and Sunley P. Do urban social enterprises benefit from agglomeration? Evidence from four UK cities, Regional Studies. This paper examines the relevance of clustering theory for an understanding of the location of social enterprises (SEs). This is accomplished through an analysis of the extent to which managers of SEs in four major UK cities perceive themselves to benefit from agglomeration effects. The paper concentrates on two broad sets of agglomeration processes: the first is Mars...

  16. Automated Manufacture of Fertilizing Agglomerates from Burnt Wood Ash

    Energy Technology Data Exchange (ETDEWEB)

    Svantesson, Thomas

    2002-12-01

    In Sweden, extensive research is conducted to find alternative sources of energy that should partly replace the electric power production from nuclear power. With the ambition to create a sustainable system for producing energy, the use of renewable energy is expected to grow further and biofuels are expected to account for a significant part of this increase. However, when biofuels are burned or gasified, ash appears as a by-product. In order to overcome the problems related to deposition in land fills, the idea is to transform the ashes into a product - agglomerates - that easily could be recycled back to the forest grounds; as a fertilizer, or as a tool to reduce the acidification in the forest soil at the spreading area. This work considers the control of a transformation process, which transforms wood ash produced at a district heating plant into fertilizing agglomerates. A robust machine, built to comply with the industrial requirements for continuous operation, has been developed and is controlled by an industrial control system in order to enable an automated manufacture.

  17. Directly Compressible Glibenclamide Tablet Prepared from Spherical Agglomerates: A Comparative Evaluation with Marketed Tablet

    Directory of Open Access Journals (Sweden)

    Sachinkumar Patil*,

    2013-01-01

    Full Text Available Agglomerates were prepared using methanol, chloroform and water as good solvent, bridging liquid and poor solvent, respectively. Directcompressible tablets of the agglomerates showed appropriate hardness, friability, weight variation and disintegration time with improved drug release than conventional marketed tablets. Tablets were adequately stable as per regulatory guidelines. Pharmacokinetic study indicated rapid absorption with higher bioavailability of the drug from the prepared tablets of agglomerates than marketed tablet (Glyburide; Sandoz. Hence, the tablets prepared with the agglomerates of glibenclamide may reduce the total dose of drug and could improve the patient compliance by reducing the dose-related side effects.

  18. Numerical derivation of forces on particles and agglomerates in a resonant acoustic field

    Science.gov (United States)

    Knoop, Claas; Fritsching, Udo

    2013-10-01

    Particles and agglomerates are investigated in gaseous acoustic flow fields. Acoustic fields exert forces on solid objects, which can influence the shape of the exposed bodies, even to the point of breakage of the structures. Motivated by experimentally observed breakage of agglomerates in an acoustic levitator (f = 20 kHz), a numerical study is presented that derives the acoustic forces on a complex model agglomerate from the pressure and velocity fields of a resonant standing ultrasound wave, calculated by computational fluid dynamics (CFD). It is distinguished between the drag and lift/lateral forces on the overall agglomerate and on the different primary particles of the model.

  19. Coating and melt induced agglomeration in a poultry litter fired fluidized bed combustor

    International Nuclear Information System (INIS)

    The combustion of poultry litter, which is rich in phosphorus, in a fluidized bed combustor (FBC) is associated with agglomeration problems, which can lead to bed defluidization and consequent shutdown of the installation. Whereas earlier research indicated coating induced agglomeration as the dominant mechanism for bed material agglomeration, it is shown experimentally in this paper that both coating and melt induced agglomeration occur. Coating induced agglomeration mainly takes place at the walls of the FBC, in the freeboard above the fluidized bed, where at the prevailing temperature the bed particles are partially molten and hence agglomerate. In the ash, P2O5 forms together with CaO thermodynamically stable Ca3(PO4)2, thus reducing the amount of calcium silicates in the ash. This results in K/Ca silicate mixtures with lower melting points. On the other hand, in-bed agglomeration is caused by thermodynamically unstable, low melting HPO42− and H2PO4− salts present in the fuel. In the hot FBC these salts may melt, may cause bed particles to stick together and may subsequently react with Ca salts from the bed ash, forming a solid bridge of the stable Ca3(PO4)2 between multiple particles. - Highlights: • Coating induced agglomeration not due to K phosphates, but due to K silicates. • Melt induced agglomeration due to H2PO4− and HPO42− salts in the fuel. • Wall agglomeration corresponds to coating induced mechanism. • In-bed agglomeration corresponds to melt induced mechanism

  20. The characteristics of bed agglomeration during fluidized bed combustion of eucalyptus bark

    International Nuclear Information System (INIS)

    The bed agglomeration behaviors were investigated experimentally when eucalyptus bark was burning tested in a laboratory scale fluidized bed reactor. The focuses of this work were the influences of operating conditions and bed materials on the bed agglomeration tendency and the elucidation in the behaviors of fuel inorganic elements and the governing mode of the agglomeration. It was found that the defluidization caused by the bed agglomeration was clearly detectable from the decrease in measured bed pressure. The growth of bed particle and accumulation of agglomerates during combustion provided the partial to complete defluidization. The defluidization was promoted by the increase of bed temperature and bed particle size, and the decrease of fluidizing air velocity. The SEM-EDS analyses revealed that the bed agglomeration was mainly attributed to the formation of potassium silicate compounds as liquid phase during the combustion. This was initiated by the chemical reaction between the bed particle and the released ash constituents. In this study, the inorganic migration from fuel particle to bed particle was likely dominated by the condensation/reaction. The thermodynamic examination by ternary phase diagram analysis corroborated that the liquid phase formation of the ash derived materials controlled the agglomeration. The alumina sand prevented the bed agglomeration since it was inactive in the formation of viscous molten substances during combustion at the observed temperatures. - Highlights: • The behaviors of bed agglomeration were studied during the fluidized bed combustion of eucalyptus bark. • The increase in bed temperature and sand size, and the decrease of air velocity promoted bed defluidization. • The formation of molten potassium silicate compounds conduced to the bed agglomeration. • Condensation/reaction was the dominant inorganic migration mechanism from fuel particle to bed particle. • The alumina sand prevented effectively the bed

  1. Discussion on the dispersion & agglomeration of aircraft industry

    Institute of Scientific and Technical Information of China (English)

    Bo Chu

    2009-01-01

    The aircraft industry is crucial to the economy and security of a nation. In this paper, the spatial characteristics and patterns of the aircraft industry are analyzed on different spatial scales. It is found that there is a 'Matthew effect' in the global aircraft industry and the spatial evolution of the industry is consistent with the industrialization process of the whole country. It is also revealed that the spatial evolution of the country is driven by both the centripetal forces including capital, talents, technology and agglomeration economies and the centrifugal forces including the comparative advantage, cost &risk sharing, emerging markets, development policy for less-developed regions and the military imperative. These forces have both market-stabilizing and market-disrupting effects on the spatial evolution of the aircraft industry. The study suggests that lessons drawn from the experiences in the United States and France are expected to be conducive to the rise of China's aircraft industry in the future.

  2. Method and apparatus for preventing agglomeration within fluid hydrocarbons

    International Nuclear Information System (INIS)

    This invention relates to a process for treating a fluid hydrocarbon fuel for retarding the agglomeration between particles thereof and for retarding the growth of bacteria and fungi therein. The process includes that steps of transporting a plurality of unit volumes of said fluid hydrocarbon fuel through an irradiating location and irradiating each unit of the plurality of unit volumes at the irradiating location with either neutron or gamma radiation. An apparatus for treating the fluid hydrocarbon fuels with the nuclear radiation also is provided. The apparatus includes a generally conical central irradiating cavity which is surrounded by a spiral outer irradiating cavity. The fluid hydrocarbon fuel is transported through the cavities while being irradiated by the nuclear radiation

  3. Intensive drying and the related microstructure features in agglomerate spheres

    Science.gov (United States)

    Kudlyk, Rostyslav

    Most metal ore concentrates are fine particulates with a wide particle-size distribution. Industrially they are pelletized by tumbling in balling discs or drums into spheres, an operation which requires the addition of typically up to 10% by weight of water. Further processing of these agglomerates involves first drying and then induration by heating up to 1250°C. The main objective of this thesis was the study of the interrelationship between the microstructure of the agglomerates with, on the one hand, the mechanical and physical properties of the pellets and their behaviour during intensive drying, on the other. The previously developed model of the drying process identified the loss of capillarity, resulting from the vapour lock, to be a critical component of the mechanism of intense as opposed to 'classical' drying. It was shown that the absence of the constant-rate drying period is a natural consequence of this effect. Several significant shortcomings of the previous model have been identified. This model treats the period of transition between surface- and shrinking-core drying as an instantaneous event. The new extended model, which overcomes the original model limitations, was developed in this project. In its formalism, the new model includes the pore-size distribution and thus simulates a gradual surface/shrinking-core transition. It was shown that the nature of the transition between the surface- and shrinking-core drying regimes during intensive drying is fundamentally different from that of classical drying, i.e. carried out at mild temperatures. In the latter case, liquid is being delivered to the surface through the network of interconnected small pores reaching the surface. The transition occurs when the larger pores, also reaching the surface, are being drained. On the other hand, under intense-drying conditions, the rate-limiting factor is the vapour lock. The latter phenomenon will occur in the smaller pores first, as they have smaller liquid

  4. Agglomeration and Deposition Behaviour of Solid Recovered Fuel

    DEFF Research Database (Denmark)

    Pedersen, Morten Nedergaard; Jensen, Peter Arendt; Nielsen, Mads;

    2015-01-01

    Waste derived fuels such as Solid Recovered Fuel (SRF) are increasingly being used in the cement industry as a means to reduce cost [1]. SRF is produced by separating the combustible fraction from industrial or municipal solid waste (MSW). The recovered fraction has a higher content of combustible...... materials such as plastic and paper than mixed MSW [2]. The inhomogeneous nature of SRF [3] makes it difficult to combust and many problems may arise concerning e.g. combustion control, feeding of fuel [2,4], deposit formation [5], or accumulation of impurities [3]. Laboratory ash fusion tests typically...... contains significant quantities of common plastics such as polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). Fluidized bed experiments to examine the pyrolysis of polymers have shown that bed agglomeration can result from melting plastics or sticky char residues in the case of...

  5. Gravitational agglomeration of post-HCDA LMFBR aerosols: nonspherical particles

    International Nuclear Information System (INIS)

    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

  6. Remediation of Sucarnoochee soil by agglomeration with fine coal

    International Nuclear Information System (INIS)

    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

  7. Fluidization and mixing of nanoparticle agglomerates assisted via magnetic impaction

    Energy Technology Data Exchange (ETDEWEB)

    Scicolone, James V.; Lepek, Daniel; Louie, Lin; Dave, Rajesh N., E-mail: dave@adm.njit.edu [New Jersey Institute of Technology, Department of Chemical, Biological and Pharmaceutical Engineering (United States)

    2013-02-15

    Mixing of nanopowders in an environmentally benign magnetically assisted fluidized bed (MAFB) system was studied. Examination of fluidization behavior of agglomerate particulate fluidization (APF; silica R974 or R972) and agglomerate bubbling fluidization (ABF; alumina or titania) nano-powders in un-assisted and MAFB systems confirmed previous results on decreased minimum fluidization velocity and increased bed expansion of APF and ABF powders due to magnetic assistance. APF and ABF powder mixtures behaved like APF powders with the bed expansions in between those of individual constituents. Unlike previous MAFB studies, fluidization as a function of time was studied to examine its influence on nano-mixing. With time, the bed expansion reduced, and reduction was faster as magnet-to-powder ratio increased from 0:1 to 5:1, although fluidization was sustained, confirmed via the pressure drop measurements. Reduction in bed expansion was attributed to change in the nature of nanoagglomerates, which showed increased density as a function of processing time, ruling out electrostatics or elutriation as major factors. Mixtures of silica (APF) and alumina (ABF), processed at various magnet-to-powder ratios, were characterized via statistical analysis from energy dispersive x-ray spectroscopy using field emission scanning electron microscope to compute homogeneity of mixing (HoM). Magnetic assistance improved the HoM as a function of time, and was strongly related to the product of number of magnets and time, similar to previous results in magnetically assisted impaction mixing (MAIM). The best achievable HoM was significantly better than unassisted fluidization and comparable to previous results for rapid expansion of high-pressure suspensions and MAIM.

  8. Fluidization and mixing of nanoparticle agglomerates assisted via magnetic impaction

    International Nuclear Information System (INIS)

    Mixing of nanopowders in an environmentally benign magnetically assisted fluidized bed (MAFB) system was studied. Examination of fluidization behavior of agglomerate particulate fluidization (APF; silica R974 or R972) and agglomerate bubbling fluidization (ABF; alumina or titania) nano-powders in un-assisted and MAFB systems confirmed previous results on decreased minimum fluidization velocity and increased bed expansion of APF and ABF powders due to magnetic assistance. APF and ABF powder mixtures behaved like APF powders with the bed expansions in between those of individual constituents. Unlike previous MAFB studies, fluidization as a function of time was studied to examine its influence on nano-mixing. With time, the bed expansion reduced, and reduction was faster as magnet-to-powder ratio increased from 0:1 to 5:1, although fluidization was sustained, confirmed via the pressure drop measurements. Reduction in bed expansion was attributed to change in the nature of nanoagglomerates, which showed increased density as a function of processing time, ruling out electrostatics or elutriation as major factors. Mixtures of silica (APF) and alumina (ABF), processed at various magnet-to-powder ratios, were characterized via statistical analysis from energy dispersive x-ray spectroscopy using field emission scanning electron microscope to compute homogeneity of mixing (HoM). Magnetic assistance improved the HoM as a function of time, and was strongly related to the product of number of magnets and time, similar to previous results in magnetically assisted impaction mixing (MAIM). The best achievable HoM was significantly better than unassisted fluidization and comparable to previous results for rapid expansion of high-pressure suspensions and MAIM.

  9. Gender Differences of Shoppers in the Marketing and Management of Retail Agglomerations

    OpenAIRE

    Teller, C; Thomson, A

    2012-01-01

    This paper aims to first identify gender differences in perception and evaluation of retail agglomerations, and second, discuss the implications of these differences for marketing and management. Based on a conceptual model 2151 agglomeration shoppers were surveyed using interviewer-administered questionnaires. Structural equation modelling revealed that accessibility, parking and infrastructure are perceived differently between gender groups. The attractiveness in terms of satisfaction, rete...

  10. Statistical Evaluation of Non-Agglomerating Coating for Granulated Natural Asphalt

    Directory of Open Access Journals (Sweden)

    Tjokorde Walmiki Samadhi

    2011-04-01

    Full Text Available Agglomeration of granulated Buton natural asphalt during storage is of major concern in its large-scale commercial application. This work develops a simple test method to evaluate the performance of agglomeration-resistant coating for granulated Buton asphalt, consisting of water-based polymeric primary coating and mineral-based secondary coating. The method uses a static load cell to measure the agglomerated granule count fraction under simulated storage conditions. A 24-1 fractional factorial experiment with two replications is employed to evaluate the effect of coating drying temperature, drying time, asphalt to secondary coating mass ratio, and secondary coating type on the agglomerated count fraction at ambient temperature and 60 oC. The test is able to measure a statistically significant increase in agglomeration resistance when the coating is applied, with an agglomerated fraction of 17.5% at 60 oC. The test identifies asphalt to secondary coating weight ratio as a significant factor, with an ANOVA p-value much lower than other effects. A decrease in this mass ratio from 5:1 to 5:2 increases the agglomeration, which is hypothesized to be attributed to the hydrated cementitious phase between granular external surfaces. More work is needed to identify the acceptable fraction of agglomerated granules.

  11. Humid storage conditions increase the dissolution rate of diazepam from solid dispersions prepared by melt agglomeration

    DEFF Research Database (Denmark)

    Jørgensen, Anna Cecilia; Torstenson, Anette Seo

    2008-01-01

    The purpose of this study is to investigate the effect of cooling mode and storage conditions on the dissolution rate of a solid dispersion prepared by melt agglomeration. The aim has been to relate this effect to the solid state properties of the agglomerates. The cooling mode had an effect on t...

  12. Acoustic agglomeration of power-plant fly ash. A comprehensive semi-annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    Reethof, G.

    1980-02-01

    Results obtained during the reporting period are presented. The agglomeration of submicron fly ash particles has been studied as a function of sound pressure level, sound frequency, loading, and exposure time. A second generation model of the agglomeration process is being developed. A high-frequency, high-intensity variable speed siren delivering at least 600 W at frequencies up to 4000 Hz has been developed and tested. Details on the design and operation are presented. The agglomeration chamber has been completely cleaned and the aerosol generating system has been rebuilt. A mathematical model of the acoustics of agglomeration is being developed. Preliminary results of computerized electron microscopic scanning of fly ash particles during agglomeration are presented. (DMC)

  13. Simulation research on monomer agglomeration of nonmetallic inclusions in steel with a diffusion limited aggregation model

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The monomer agglomeration of nonmetallic inclusions was simulated with a diffusion limited aggregation (DLA) model of the fractal theory.The simulation study with a random two-dimensional diffusion was carried out.The results indicate that the DLA model can be used for the simulation of agglomeration behavior of the cluster-type inclusions.The morphology of clusters was observed with SEM and compared with the simulated agglomerates.The modelling procedure of the DLA model is applicable for the agglomeration process.The uncertainty of agglomeration process and the persuasive average agglomerative ratio was analyzed.The factors about the agglomerative ratio with the collision path distance and the size of particles or seed were discussed.The adherence of the nonmetallic inclusions on the dam, the weir and the walls of a tundish, and the absorption of inclusions by stopper or nozzle were also discussed.

  14. AN INVESTIGATION OF THE HYDROPHOBIC AGGLOMERATION CHARACTERISTICS OF EASY DEGRADATION COAL FINES IN WATER

    Institute of Scientific and Technical Information of China (English)

    王力; 陈鹏

    1997-01-01

    The separation of ultrafine coal from three Chinese coal samples of easy degradation coal fines in water has been investigated by the application of a hydrophobic agglomeration process. In addition to yielding clean coal with high recovery, this process requires significantly less oil concentration for agglomeration (less than 0.4% in oil-water weight ratio) and produces stabler agglomerates than general oil agglomeration process, the cost of the oil would no longer be an important consideration for its commercial application. Neutral diesel oil was used to make oleophilic coal particles agglomerated with good rejection of clay minerals under little oil consumption and certain agitation speed at 2000 r/min. An important advantage of this process compared with other cleaning fine coal methods is that it can extremely reduce or eliminate the effects of coal degradation and some clay minerals on coal preparation.

  15. Prediction of mass fraction of agglomerated debris in a LWR severe accident

    International Nuclear Information System (INIS)

    Ex-vessel termination of accident progression in Swedish type Boiling Water Reactors (BWRs) is contingent upon efficacy of melt fragmentation and solidification in a deep pool of water below reactor vessel. When liquid melt reaches the bottom of the pool it can create agglomerated debris and “cake” regions that increase hydraulic resistance of the bed and affect coolability of the bed. This paper discusses development and application of a conservative-mechanistic approach to quantify mass fractions of agglomerated debris. Experimental data from the DEFOR-A (Debris Bed Formation and Agglomeration) tests with high superheat of binary oxidic simulant material melt is used for validation of the methods. Application of the approach to plant accident analysis suggests that melt superheat has less significant influence on agglomeration of the debris than jet penetration depth. The paper also discusses the impact of the uncertainty in the jet disintegration and penetration behavior on the agglomeration mode map. (author)

  16. Agglomeration behaviour of high ash Indian coals in fluidized bed gasification pilot plant

    International Nuclear Information System (INIS)

    Although gasification of high ash Indian coals is gaining importance, the resultant uncertainties associated with agglomerate formation are still unresolved. To address this, a suitable pilot scale Fluidized Bed Gasifier was utilized in this study. Stabilized operating conditions in terms of coal feed rate, air feed rate, bed temperature, etc., already identified for maximum possible carbon conversion, were maintained in all experiments and the steam flow rate was only varied. Though the ash fusion temperature of the coals were above 1200 °C, agglomerate was formed during gasification at 950 °C with ‘steam to coal ratio’ less than 0.15 (kg/kg). On increasing this ratio above 0.2 local heat-concentration and agglomeration could be avoided with certainty. Chemical composition alone was not sufficient to explain the relative strength of ash-agglomerates. Compositional variation and state of iron within the matrix were assessed through SEM-EDX and electron paramagnetic resonance (EPR) study, respectively. The probing also required the ash-loading and iron-loading factors to be freshly defined in the context of gasification. Localized heat, large compositional variation, presence of iron in Fe2+ state, ash-loading/iron-loading factors influenced intensity of agglomerate formation. Finally, low temperature agglomerate formation was explained by SiO2–Al2O3–FeO phase diagram. - Highlights: • Pilot plant studies on agglomerate formation during high ash coal gasification. • AFT, chemical analysis of coal ash could not give proper indication. • Ash-/iron-loading factors, compositional variation, Fe2+ leads to agglomeration. • Steam to coal ratio was controlled judiciously to avoid agglomeration. • Cause for agglomeration investigated in depth and remedial adjustment was focused

  17. Spherically agglomerated solid dispersions of valsartan to improve solubility, dissolution rate and micromeritic properties

    Directory of Open Access Journals (Sweden)

    Amit R. Tapas

    2011-04-01

    Full Text Available The objective of the present work was to enhance the solubility and dissolution rate of valsartan (VAL a poorly water soluble antihypertensive, by spherically agglomerated solid dispersions using methanol, water and dichloromethane as good solvent, poor solvent and bridging liquid, respectively. The hydrophilic polymers like polyvinyl pyrrolidone, Hydroxypropyl β-cyclodextrin, Hydroxypropyl methylcellulose were used in agglomeration process. The pure drug (VAL and its agglomerates with different polymers were characterize by differential scanning calorimetry (DSC, X-ray diffraction (XRD, IR spectroscopic studies and scanning electron microscopy (SEM. The DSC results indicated that decrease in melting enthalpy related to disorder in the crystalline content. XRD studies also showed changes in crystallanity, IR spectroscopy revealed that there were no chemical changes in the recrystallized agglomerates. The spherically agglomerated solid dispersions with different polymers exhibited marked increase in solubility, dissolution rate and micromeritic properties (bulk density, flow property, compactability compared with VAL. The SEM studies showed that the agglomerates posseeses a good spherical shape.Keywords: Valsartan; Spherical agglomeration; Solid dispersion; Solubility; Dissolution rate; Micromeritic properties.

  18. Nanoparticle agglomeration in an evaporating levitated droplet for different acoustic amplitudes

    Science.gov (United States)

    Tijerino, Erick; Basu, Saptarshi; Kumar, Ranganathan

    2013-01-01

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

  19. Coke yield and heat transfer in reaction of liquid-solid agglomerates of Athabasca vacuum residue

    Energy Technology Data Exchange (ETDEWEB)

    Ali, M.; Courtney, M.; Boddez, L.; Gray, M. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering

    2010-02-15

    Delayed coking and fluid-bed coking are the most common commercial processes used by the petroleum industry for the thermal conversion of vacuum residues into petroleum distillate products. This paper presented the results of an experimental study of coke yield at long reaction times from agglomerates of coke particles and Athabasca vacuum residue (AVR). The ultimate coke yield was determined for a range of agglomerate thicknesses, liquid concentrations and reaction temperatures. The agglomerates were heated on Curie-point alloy strips in an induction furnace at 503 and 530 degrees C until all toluene-soluble material was converted. A simple heat transfer model was used to describe the temperature profile within the agglomerates. Coke yield results from agglomerates were compared to the coke yield results from reacting thin films of vacuum residue. The average coke yield from the agglomerates was 23 per cent, while the coke yield from thin films of 20 {mu}m thickness was 11 per cent, which supports the role of mass transfer in coke formation reactions. The ultimate coke yield was insensitive to vacuum residue concentration, agglomerate size, and reaction temperature. According to control experiments on thin films of liquid at different heating rates, the temperature-time history has little effect on the ultimata coke yield. 13 refs., 2 tabs., 10 figs.

  20. APPLICATION OF SPHERICAL AGGLOMERATION TECHNIQUE TO IMPROVE MICROMERITIC PROPERTIES AND DISSOLUTION CHARACTERISTICS OF NABUMETONE

    Directory of Open Access Journals (Sweden)

    Pradnya Patil

    2012-01-01

    Full Text Available The present work is aimed to enhance the solubility and dissolution rate of Nabumetone, 4-(6-methoxy-2-naphalenyl-2-butanone water insoluble anti-inflammatory drug by spherical agglomeration technique using a solvent change method consisting of acetone, water and dichloromethane as solvent, non solvent and bridging liquid respectively. The hydrophilic polymers like poly vinyl pyrrolidone K-30 (PVP and sodium alginate were used in the agglomeration process. Infrared (I.R spectroscopic studies, Differential scanning calorimetery (DSC and Scanning electron microscopy (SEM were used for characterization of pure drug and its agglomerates. The I.R spectroscopy revealed that there is no chemical interaction between drug and polymers, also indicated that no chemical changes in the crystallized agglomerates .The agglomerates exhibited significantly improved solubility, dissolution rate and micromeritic properties (angle of repose, Carr’s index, bulk density, tapped density. Hausner’s ratio compared with pure drug Nabumetone. The aqueous solubility and dissolution rate of the drug from spherical agglomerates was significantly (p < 0.05 increased (nearly two times. SEM studies revealed that the agglomerates possess a good spherical shape. The study revealed that Micromeritic Properties, Solubility and Invitro drug release rate is increased with increase in PVP concentration from 0.25% to 1% as compared to sodium alginate.

  1. MORPHOLOGICAL AND MICROSTRUCTURAL CHANGES DURING THE HEATING OF SPHERICAL CALCIUM ORTHOPHOSPHATE AGGLOMERATES PREPARED BY SPRAY PYROLYSIS

    Institute of Scientific and Technical Information of China (English)

    Kiyoshi Itatani; Mari Abe; Tomohiro Umeda; Ian J. Davies; Seiichiro Koda

    2004-01-01

    The microstructural changes taking place during heating of calcium orthophosphate (Ca3(PO4)2) agglomerates were examined in this study. The starting powder was prepared by the spray-pyrolysis of calcium phosphate (Ca/P air-liquid nozzle. The spray-pyrolyzed powder was found to be composed of dense spherical agglomerates with a mean diameter of 1.3 μm. This powder was further heat-treated at a temperature between 800 and 1400 ℃ for 10 min. When the spray-pyrolyzed powder was heated up to 900 ℃, only βCa3(PO4)2 was detected, and the mean pore size of the spherical agglomerates increased via the (i) elimination of residual water and nitrates, (ii) rearrangement of primary particles within the agglomerates, (iii) coalescence of small pores (below 0.1 μm), and (iv) coalescence of agglomerates with diameters below 1 μm into the larger agglomerates. Among the heat-treated powders, pore sizes within the spherical agglomerates were observed to be the largest (mean diameter: 1.8 μm) for the powder heat-treated at 900 ℃ for 10 min.With an increase in heat-treatment temperature up to 1000 ℃, the spherical agglomerates were composed of dense shells. Upon further heating up to 1400 ℃, the hollow spherical agglomerates collapsed as a result of sintering via the phase transformation from β- to α-Ca3(PO4)2 (1150 ℃), thus leading to the formation of a three-dimensional porous network.

  2. Understanding lateritic ore agglomeration behaviour as a precursor to enhanced heap leaching

    International Nuclear Information System (INIS)

    Although nickel (Ni) laterite ores constitute the majority of Ni mineralization resource world-wide, in contrast to Ni sulphides, their processing via conventional beneficiation (e.g. multi-gravity and flotation) and hydrometallurgical routes is intractable as they are predominantly low grade and complex, both mineralogically and chemically. Due to their physico-chemical characteristics, low grade lateritic ores require more aggressive but costly chemical and hydrometallurgical techniques (e.g., leaching in high pressurized tanks) for value metal (Ni and Co) extraction. Processing such ores through cost-competitive heap (4-10 m high) leaching as an alternative, requires successful agglomeration of the feed into robust and porous granules. To date, producing of granules with desirable attributes poses a major geotechnical challenge to industry. In the present work, we investigate agglomeration behaviour of siliceous goethite Ni laterite ore and selected oxides and clay minerals (hematite, quartz and kao-linite) which constitute the predominant host gangue phases of typical low grade Ni laterite ores. Fundamental knowledge and understanding of the agglomeration mechanisms and kinetics which are essential for producing robust real ore granules, and pivotal to the subsequent heap leaching process, are gleaned. Isothermal, batch agglomeration tests involving 30 and 44 % w/w sulphuric acid solution as a binder indicated that 5 – 40 mm granules of differing roughness and morphologies were produced in 8-14 min. The results showed feed characteristics (e.g., mineralogy and particle size distribution) and binder content (15-25 wt.%) dependent agglomeration behaviour. Slow agglomerate nucleation and growth were displayed by the kaolinite clay mineral whilst the oxides exhibited faster agglomeration kinetics. Siliceous goethite feed ore fine/coarse ratio, H2SO4 binder dosage and acid content, product drying temperature and aging conditions, all showed significant impact on

  3. Cooperative Game Among Cities in Urban Agglomerations and Economical Sustainable Development

    Institute of Scientific and Technical Information of China (English)

    Shah Weidong

    2004-01-01

    This paper analyses redounded profits of cooperation and non-cooperation among cities in urban agglomerations based on game theory. It discusses the problems of economical development among cities with feeble cooperation, and deduces the conclusion that only cooperation of cities produces the maximum profits and realizes Pareto efficiency for cities and urban agglomerations. The paper states that cooperation is the cornerstone of economic sustainable development in urban agglomerations in profits produced by cooperation among cities.Some suggestions to accelerate cooperation among cities are proposed.

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

    Energy Technology Data Exchange (ETDEWEB)

    1991-09-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    1991-09-01

    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.

  6. Assessment of Traffic Noise on Highway Passing from Urban Agglomeration

    Science.gov (United States)

    Vijay, Ritesh; Kori, Chandan; Kumar, Manoj; Chakrabarti, T.; Gupta, Rajesh

    2014-09-01

    Assessment of traffic noise pollution in developing countries is complex due to heterogeneity in traffic conditions like traffic volume, road width, honking, etc. To analyze the impact of such variables, a research study was carried out on a national highway passing from an urban agglomeration. Traffic volume and noise levels (L10, Lmin, Lmax, Leq and L90) were measured during morning and evening peak hours. Contribution of noise by individual vehicle was estimated using passenger car noise unit. Extent of noise pollution and impact of noisy vehicles were estimated using noise pollution level and traffic noise index, respectively. Noise levels were observed to be above the prescribed Indian and International standards. As per audio spectrum analysis of traffic noise, honking contributed an additional 3-4 dB(A) noise. Based on data analysis, a positive relationship was observed between noise levels and honking while negative correlation was observed between noise levels and road width. The study suggests that proper monitoring and analysis of traffic data is required for better planning of noise abatement measures.

  7. Capillary condensation onto titania (TiO2) nanoparticle agglomerates.

    Science.gov (United States)

    Kim, Seonmin; Ehrman, Sheryl H

    2007-02-27

    A capillary condensation process was developed for the purpose of forming interconnections between nanoparticles at low temperatures. The process was performed in a temperature-controlled flow chamber on nanoparticle agglomerates deposited at submonolayer coverage on a transmission electron microscope grid. The partial pressure of the condensing species, tetraethyl orthosilicate, and the temperature of the chamber were adjusted in order to obtain the various saturation conditions for capillary condensation. The modified samples were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, BET surface area method, and scanning transmission electron microscopy with electron energy-loss spectrometry. Experimental results show that bridge-shaped layers were dominantly formed in the neck region between particles and were composed of amorphous silica. The analysis of TEM micrographs verified that the coverage of the layers is strongly dependent on the saturation ratio. Image analysis of TEM micrographs shows that this dependency is qualitatively in agreement with theoretical predictions based on the classical Kelvin equation for the specific geometries in our system. PMID:17243733

  8. Daqing Petrochemical Adopted Technology of Agglomeration New Energy Saving Production%Daqing Petrochemical Adopted Technology of Agglomeration New Energy Saving Production

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    To reduce energy consumption of equipment and exhaust emission to the uttermost, Daqing Petrochemical Company has developed pre-agglomeration production flow successfully and confirmed an optimized energy-saving method of differential pressure agglomeration. For a long time, BR equipment of 80,000 tons per year in Daqing Petrochemical Company have been adopting general isobaric technology and elutriation method to separate polymer and solvent, which caused over 10 tons of steam per ton of rubber and restricted the energy conservation and emission reduction of the enterprise.

  9. VizieR Online Data Catalog: Agglomerate of early-type Hipparcos stars (Caballero+, 2008)

    Science.gov (United States)

    Caballero, J. A.; Dinis, L.

    2009-01-01

    We study the spatial structure and sub-structure of regions rich in Hipparcos stars with blue BT-VT colours. These regions, which comprise large stellar complexes, OB associations, and young open clusters, are tracers of on-going star formation in the Galaxy. The DBSCAN (Density-Based Spatial Clustering of Applications with Noise) data clustering algorithm is used to look for spatial overdensities of early-type stars. Once an overdensity, "agglomerate", is identified, we carry out a data and bibliographic compilation of their star member candidates. The actual membership in agglomerate of each early-type star is studied based on its heliocentric distance, proper motion, and previous spectro-photometric information. We identify 35 agglomerates of early-type Hipparcos stars. Most of them are associated to previously known clusters and OB associations. The previously unknown P Puppis agglomerate is subject of a dedicated study with Virtual Observatory tools. (2 data files).

  10. The Integration and Sustainable Development of Chengdu-Chongqing Urban Agglomeration

    Institute of Scientific and Technical Information of China (English)

    Yang Jie; Mao Hanying

    2006-01-01

    Urban Agglomeration is an inevitable outcome of urbanization and industrialization, and a main form of urban development. Based on the analysis of urbanization and urban system situation, this paper will discuss the integration of urban agglomeration development, using the urban area of Cheng (Chengdu)-Yu (Chongqing)Urban agglomeration (CYUA) as a case study. By means of industries, population and spatial integrations, the function, strength and competition of CYUA will be improved and this urban agglomeration will transit from a budding state to a growing and mature one in future. The sustainable development of CYUA will depend on countermeasures, such as accelerating industrialization and urbanization, building a traffic network and express roads, strengthening the ability of self-sufficiency,enlarging the ecological construction and environmental protection, and establishing the synergetic institution of cross districts.

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

    Science.gov (United States)

    Knoop, Claas; Fritsching, Udo

    2014-03-01

    In this paper the acoustic forces on particles and agglomerates caused by high-intensity ultrasound in gaseous atmosphere are derived by means of computational fluid dynamics (CFD). Sound induced forces cause an oscillating stress scenario where the primary particles of an agglomerate are alternatingly pressed together and torn apart with the frequency of the applied wave. A comparison of the calculated acoustic forces with respect to the inter particle adhesion forces from Van-der-Waals and liquid bridge interactions reveals that the separation forces may reach the same order of magnitude for 80 μm sized SiO2-particles. Hence, with finite probability acoustically agitated gases may de-agglomerate/disperse solid agglomerate structures. This effect is confirmed by dispersion experiments in an acoustic particle levitation setup. PMID:24152872

  12. Agglomeration Evolution of Nano-Particles Aluminium in Normal Incident Shock Wave

    Institute of Scientific and Technical Information of China (English)

    YAN Zheng-Xin; WU Jing-He; HU Dong; YANG Xiang-Dong

    2006-01-01

    Agglomeration behaviour of nano-particle aluminium (nano-Al) in normal incident shock waves is investigated by our devised shock tube technology. The morphology, particle size, agglomeration process of nano-Al studied in normal incident shock waves are comprehensible evaluated by x-ray diffraction, transmission electron microscopy and scanning electron microscopy. The above-mentioned techniques show that the high strength and temperature of incident shock wave give a chance for activity of nano-Al in the reactions and decrease the agglomeration, and the morphology of agglomeration is affected by the temperature of nano-Al reaction region. The dynamic temperature of reaction region determined by the intensity ratio of two AlO bands is 2602K, which is closer to nano-Al actual reacted temperature than the determined temperature of ordinary methods (i.e. six channel instantaneous optical pyrometer; plank black body radiation law, etc.)

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

    Directory of Open Access Journals (Sweden)

    Maryam Maghsoodi

    2015-03-01

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

  14. Agglomeration Economies, Inventors and Entrepreneurs as Engines of European Regional Productivity

    NARCIS (Netherlands)

    Bosma, Niels; van Oort, Frank

    2012-01-01

    In economic agglomeration studies, the distinction of various externalities circumstances related to knowledge spillovers remains largely unclear. This paper introduces human capital, innovation and several types of entrepreneurship as potential drivers of regional economic performance with an impac

  15. Application of agglomerated acid heap leaching of clay-bearing uranium ore in China

    International Nuclear Information System (INIS)

    The permeability of ore mass has a great influence on the leaching period of heap leaching and the leaching efficiency, hence the uranium ores with high content of clay present a significant difficulty to acidic heap leaching. The Research Institute of Uranium Mining has engaged over years of studies on the cementing agents of acidic agglomeration, agglomeration method, as well as the curing measures of pelletted balls. On the basis of these studies, several types of clay-bearing ores have been tested with good results. The technique of agglomerated acid heap leaching has been successfully applied in a uranium mine. Since agglomeration has effectively increased the permeability of ore mass, its leaching period is decreased from 200 days to 60 days, the leaching efficiency from less than 40% up to 96%, comparing with direct heap leaching programme. (author)

  16. Mechanism of Agglomerating Development of Industrial Space: A Case Study on Shenzhen

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    <正>The agglomeration of industries refers to the concentration and aggregation of the same or different industries in a certain area. After analyzing the spatial pattern of the economic activities in the world, it can be found

  17. Light-Induced Agglomeration and Diffusion of Different Particles with Optical Tweezers

    Institute of Scientific and Technical Information of China (English)

    LI Xue-Cong; SUN Xiu-Dong; LIU Hong-Peng; ZHANG Jian-Long

    2010-01-01

    @@ The dynamic process of light-induced agglomeration of carbon nanotubes(CNTs),C60 and Escherichia coli(E.coli)in aqueous solutions is demonstrated using an optical tweezers system.Based on the results,the diameter of the agglomerated region and the agglomeration rate increase with the increasing laser power.After the saturation-stable period,CNTs diffuse completely,C60 dusters only diffuse partially,and E.coli never diffuses in the agglomeration region.Theoretical analyses show that the molecular polarization and thermal diffusion of particles play crucial roles in the diffusion process.The results indicate the possibility of using light to aggregate and sort nanoparticles.

  18. Particle Size Distribution, Powder Agglomerates and Their Effects on Sinterability of Ultrafine Alumina Powders

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An intensive study of the particle size distribution of four commercial ultrafine alumina powders to obtain information about the powder agglomeration and relate them to the compactibility and the sinterability has been made.

  19. Spatial Agglomeration and Productivity of Textile and Leather Manufacturing in the Punjab Province of Pakistan

    OpenAIRE

    Asim Iqba; Muhammad Wasif Siddiqi

    2013-01-01

    This study investigates whether spatial agglomeration of textile and leather industry facilitates to enhance its own productivity at establishment level in the Punjab province of Pakistan. The empirical analysis is based on the survey data for the years 1995-96, 2000-2001 and 2005-06 collected from the Punjab Bureau of Statistics (PBS). The production function framework has been utilized. The results of production function suggest that spatial agglomeration of textile and leather industry pla...

  20. Explaining the productivity advantages of manufacturing firms in Russian urban agglomerations

    OpenAIRE

    Gonchar, Ksenia; Ratnikova, Tatyana

    2013-01-01

    This paper empirically analyzes the agglomeration-related productivity premium at the enterprise level of the manufacturing industry in Russia. A settlement is counted as part of an urban agglomeration in two cases: that of a large, central city and that of a town located within 50 kilometers of the central city. Data obtained from a 2009 manufacturing enterprise survey conducted by the Higher School of economics are used, along with linked data on hosting regions and cities. We employ a mult...

  1. A Treatise on the Geographical Scale of Agglomeration Externalities and the MAUP

    OpenAIRE

    Burger, Martijn J.; van Oort, Frank G.; Bert van der Knaap

    2010-01-01

    In this article, we test to what extent the Modifiable Areal Unit Problem (MAUP) moderates the effect of agglomeration externalities on areal sectoral employment growth by varying the initial geographical scale of analysis. Using spatial cross-regressive modelling, we find different effects of agglomeration forces across geographical scales. As the MAUP is a theoretical as well as a methodological problem, research should not only work with proper statistical specifications, but also relate t...

  2. Tourism agglomeration and its impact on social welfare: an empirical approach to the Spanish case

    OpenAIRE

    2006-01-01

    This paper measures two descriptors of tourism namely, its scale and agglomeration level and subsequently evaluates both descriptors according to their direct and joint impacts on the host communities' quality of life. The key constructs for this research are the following: (1) a tourism evaluation function that incorporates the scale and agglomeration of tourism, which is constructed for each one of the 50 Spanish provinces; and (2) a measure of the host communities' quality of life that com...

  3. Agglomeration Economies, Inventors and Entrepreneurs as Engines of European Regional Productivity

    OpenAIRE

    Bosma, Niels; van Oort, Frank

    2012-01-01

    In economic agglomeration studies, the distinction of various externalities circumstances related to knowledge spillovers remains largely unclear. This paper introduces human capital, innovation and several types of entrepreneurship as potential drivers of regional economic performance with an impact of agglomeration economies. We use measures of specific types of entrepreneurship, discerned at the individual level, as well as human capital and invention through patenting activity for the per...

  4. How agglomeration in the financial services industry influences economic growth: Evidence from Chinese cities

    OpenAIRE

    Liang, Lin; Lin, Shanglang; LI, YONG

    2014-01-01

    This paper empirically tests the effect of financial knowledge spillovers on agglomeration in China's financial services industry and examines the external effects on cities' economies. The authors apply hierarchical linear modeling to examine a data set that comprises 276 Chinese cities and draw the following conclusions. Firstly, they find that agglomeration in the financial services industry and the Jacobs spillovers of industry diversification both promote financial knowledge spillovers i...

  5. Distribution Characteristics and Compressibility of Agglomerates as a Reflection of Granulation Parameters

    OpenAIRE

    Macho Oliver; Peciar Peter; Peciar Marián; Svěrák Tomáš

    2015-01-01

    Selective adjustment of the properties of particular material agglomeration has its inherent place in the chemical, food, but especially in the pharmaceutical, industry. The requirement to produce an agglomerate with desired particle size at a given strength is often formulated. To create the targeted product, it is necessary to know the process parameters affecting the preparation of its features. This paper deals with survey distribution characteristics and compressibility changes of an agg...

  6. Strategic location behaviour: Temporal and spatial proximity in situation of agglomeration effects

    OpenAIRE

    Mayer, Thierry; Mucchielli, Jean-Louis

    1996-01-01

    We address the question of competition within the location choices of firms. In a framework of agglomeration effects, both spatial and temporal dimensions of the firms' decisions are studied. We show that the competition consequences of preemptive move and optimal time of entry can interfere with the geographical decisions. Our results contrast with those of agglomeration economics models which generally provide extreme results of mono-location. The Stackelberg equilibria described here tend ...

  7. Competitors, Complementors, Parents and Places: Explaining Regional Agglomeration in the U.S. Auto Industry

    OpenAIRE

    Luis Cabral; Zhu Wang; Daniel Yi Xu

    2013-01-01

    Taking the early U.S. automobile industry as an example, we evaluate four competing hypotheses on regional industry agglomeration: intra-industry local externalities, inter-industry local externalities, employee spinouts, and location fixed-effects. Our findings suggest that inter-industry spillovers, particularly the development of the carriage and wagon industry, play an important role. Spinouts play a secondary role and only contribute to agglomeration at later stages of industry evolution...

  8. Hedonic and Utilitarian Shopper Types in Evolved and Created Retail Agglomerations

    OpenAIRE

    Teller, C; Reutterer, T; Schnedlitz, P

    2008-01-01

    This paper focuses on the impact of hedonic and utilitarian values of shopping on retail agglomeration patronage issues, in particular on the shopping behaviour and the perception of retail agglomerations. Our empirical study is based on a discussion of agglomerations’ potential to attract utilitarian and hedonic shopper types. A sample of 2,139 customers were interviewed in a peripheral shopping mall and an inner city shopping street and confronted with a multi-item scale operationalising sh...

  9. Agglomeration in counter-current spray drying towers. Part B: Interaction between multiple spraying levels

    OpenAIRE

    Francia, V; Martín, L; Bayly, AE; Simmons, MJH

    2016-01-01

    A new experimental method is developed here to investigate agglomeration in spray drying towers operating with multiple nozzles. It allows studying independently the contribution of each spray to the product and obtaining a valuable insight into the agglomeration processes. The paper studies a two level swirl counter-current dryer of detergent in a full-scale production system. It shows that operation with two nozzle levels increases the energy efficiency compared to the use of single sprays,...

  10. Stable Partial Agglomeration in a New Economic Geography Model with Urban Frictions

    OpenAIRE

    Barde, Sylvain

    2007-01-01

    This paper extends the Puga (1999) model by introducing urban frictions. It assumes that the agglomeration of manufacturing in a city imposes a cost on the inhabitants of the agglomerated region. Furthermore, an implicit function methodology is developed to provide a numerical stability function that does not require prior analytical work. Simulations reveal that these numerical stability conditions are consistent with the original Puga (1999) analytical predictions. The central finding is th...

  11. Laser-induced agglomeration of gold nanoparticles dispersed in a liquid

    International Nuclear Information System (INIS)

    Highlights: • Pulsed laser irradiation of dense gold nanoparticles colloidal solution can result in their agglomeration. • Gas bubbles in-phase pulsation induced by laser radiation accounts for nanoparticles agglomeration. • Time evolution of the size distribution function proceeds in activation mode. • The electrostatic-like model of nanoparticles agglomeration is in good correspondence with the experimental data. - Abstract: Dynamics of gold nanoparticles (NPs) ensemble in dense aqueous solution under exposure to picosecond laser radiation is studied both experimentally and theoretically. Properties of NPs are examined by means of transmission electron microscopy, optical spectroscopy, and size-measuring disk centrifuge. Theoretical investigation of NPs ensemble behavior is based on the analytical model taking into account collisions and agglomeration of particles. It is shown that in case of dense NPs colloidal solutions (above 1014 particles per milliliter) the process of laser fragmentation typical for nanosecond laser exposure turns into laser-induced agglomeration which leads to formation of the particles with larger sizes. It is shown that there is a critical concentration of NPs: at higher concentrations agglomeration rate increases tremendously. The results of mathematical simulation are in compliance with experimental data

  12. Design of Agglomerated Crystals of Ibuprofen During Crystallization: Influence of Surfactant

    Directory of Open Access Journals (Sweden)

    Maryam Maghsoodi

    2011-01-01

    Full Text Available Objective(sIbuprofen is a problematic drug in tableting, and dissolution due to its poor solubility, hydrophobicity, and tendency to stick to surface. Because of the bad compaction behavior ibuprofen has to be granulated usually before tableting. However, it would be more satisfactory to obtain directly during the crystallization step crystalline particles that can be directly compressed and quickly dissolved. Materials and Methods Crystallization of ibuprofen was carried out using the quasi emulsion solvent diffusion method in presence of surfactant (sodium lauryl sulfate (SLS, Tween 80. The particles were characterized by differential scanning calorimetry (DSC, powder X-ray diffraction (XRPD and were evaluated for particle size, flowability, drug release and tableting behavior. ResultsIbuprofen particles obtained in the presence of surfactants consisted of numerous plate- shaped crystals which had agglomerated together as near spherical shape. The obtained agglomerates exhibited significantly improved micromeritic properties as well as tableting behavior than untreated drug crystals. The agglomerates size and size distribution was largely controlled by surfactant concentration, but there was no significant influence found on the tableting properties. The dissolution tests showed that the agglomerates obtained in presence of SLS exhibited enhanced dissolution rate while the agglomerates made in the presence of Tween 80 had no significant impact on dissolution rate of ibuprofen in comparison to untreated sample. The XRPD and DSC results showed that during the agglomeration process, ibuprofen did not undergo any polymorphic changes.Conclusion The study highlights the influence of surfactants on crystallization process leading to modified performance.

  13. A Study on the Density of Agglomerates Prepared from Cork Wastes

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The density of black regranulate (BR) of cork and of black agglomerate (BA) and composite agglomerate (CA) prepared fromsuch a waste by different methods was investigated. The preparation of the agglomerates was undertaken by controlling thespecimen thickness for BA and the particle size for BR and the binder dosage for CA. The mass changes produced in theoven-drying treatment at 376.15 K of the agglomerates and in their subsequent stabilization under ambient conditions werealso analyzed. The density was determined by standard methods. For BR, the bulk density first decreased and then increasedwith decreasing particle size. It was much lower than the apparent density of the agglomeration products of cork. Although toa lesser extent, the density was also lower for BA than for CA. It was higher for the smaller thickness specimens of BA. In thecase of CA, the density followed the same variation trends as for BR. Furthermore it increased significantly with the increasein resin dosage. This resulted in a noticeable increase in the weight loss during the oven-drying and in a significant decreasein the degree of moisture adsorption during the stabilization period of the agglomerate.

  14. Study on the Policy Factors of Innovative Talents Agglomeration in Jiangsu Province based on Data Analysis

    Directory of Open Access Journals (Sweden)

    Li Wenfei

    2016-03-01

    Full Text Available Innovative talent is the key factor to promote the development of innovative economy and realize innovative drive in Jiangsu Province. Innovative talent agglomeration can fully play the effect of innovative talents through the agglomeration efficiency. Among many factors that affect the agglomeration of innovative talents, the guiding role of government policy factors is becoming more and more important. Based on the survey of domestic and foreign literature, through questionnaire survey, this paper combines relevant analysis and regression analysis to study the mechanism between the of scientific research funds investment, household registration policy, outstanding achievement award and patent licensing and the innovative talent agglomeration. The results show that the investment of scientific research funds, the household registration policy, the outstanding achievement award and the patent authorization have remarkable influence on the innovation talent agglomeration. The conclusion of this study not only expands the theoretical research field of government policy and innovative talent agglomeration, but also provides practical guidance for the government of Jiangsu Province in the era of innovation knowledge.

  15. Effect of hydration repulsion on nanoparticle agglomeration evaluated via a constant number Monte–Carlo simulation

    International Nuclear Information System (INIS)

    The effect of hydration repulsion on the agglomeration of nanoparticles in aqueous suspensions was investigated via the description of agglomeration by the Smoluchowski coagulation equation using constant number Monte–Carlo simulation making use of the classical DLVO theory extended to include the hydration repulsion energy. Evaluation of experimental DLS measurements for TiO2, CeO2, SiO2, and α-Fe2O3 (hematite) at high IS (up to 900 mM) or low |ζ-potential| (≥1.35 mV) demonstrated that hydration repulsion energy can be above electrostatic repulsion energy such that the increased overall repulsion energy can significantly lower the agglomerate diameter relative to the classical DLVO prediction. While the classical DLVO theory, which is reasonably applicable for agglomeration of NPs of high |ζ-potential| (∼>35 mV) in suspensions of low IS (∼<1 mM), it can overpredict agglomerate sizes by up to a factor of 5 at high IS or low |ζ-potential|. Given the potential important role of hydration repulsion over a range of relevant conditions, there is merit in quantifying this repulsion energy over a wide range of conditions as part of overall characterization of NP suspensions. Such information would be of relevance to improved understanding of NP agglomeration in aqueous suspensions and its correlation with NP physicochemical and solution properties. (paper)

  16. Laser-induced agglomeration of gold nanoparticles dispersed in a liquid

    Energy Technology Data Exchange (ETDEWEB)

    Serkov, A.A.; Shcherbina, M.E. [Wave Research Center of A.M. Prokhorov General Physics Institute of the Russian Academy of Sciences, 38, Vavilov Street, 119991 Moscow (Russian Federation); The Federal State Educational Institution of Higher Professional Education, Moscow Institute of Physics and Technology (State University), Moscow (Russian Federation); Kuzmin, P.G., E-mail: qzzzma@gmail.com [Wave Research Center of A.M. Prokhorov General Physics Institute of the Russian Academy of Sciences, 38, Vavilov Street, 119991 Moscow (Russian Federation); Kirichenko, N.A. [Wave Research Center of A.M. Prokhorov General Physics Institute of the Russian Academy of Sciences, 38, Vavilov Street, 119991 Moscow (Russian Federation); The Federal State Educational Institution of Higher Professional Education, Moscow Institute of Physics and Technology (State University), Moscow (Russian Federation)

    2015-05-01

    Highlights: • Pulsed laser irradiation of dense gold nanoparticles colloidal solution can result in their agglomeration. • Gas bubbles in-phase pulsation induced by laser radiation accounts for nanoparticles agglomeration. • Time evolution of the size distribution function proceeds in activation mode. • The electrostatic-like model of nanoparticles agglomeration is in good correspondence with the experimental data. - Abstract: Dynamics of gold nanoparticles (NPs) ensemble in dense aqueous solution under exposure to picosecond laser radiation is studied both experimentally and theoretically. Properties of NPs are examined by means of transmission electron microscopy, optical spectroscopy, and size-measuring disk centrifuge. Theoretical investigation of NPs ensemble behavior is based on the analytical model taking into account collisions and agglomeration of particles. It is shown that in case of dense NPs colloidal solutions (above 10{sup 14} particles per milliliter) the process of laser fragmentation typical for nanosecond laser exposure turns into laser-induced agglomeration which leads to formation of the particles with larger sizes. It is shown that there is a critical concentration of NPs: at higher concentrations agglomeration rate increases tremendously. The results of mathematical simulation are in compliance with experimental data.

  17. Two-level hierarchical structure in nano-powder agglomerates in gas media

    Science.gov (United States)

    de Martin, Lilian; Bouwman, Wim G.; van Ommen, J. Ruud

    2012-11-01

    Nanoparticles in high concentration in a gas form agglomerates due to the interparticle van der Waals forces. The size and the internal structure of these nanoparticles agglomerates strongly influence their dynamics and their interaction with other objects. This information is crucial, for example, when studying inhalation of nanoparticles. It is common to model the structure of these agglomerates using a fractal approach and to compare their dimension with the dimension obtained from aggregation models, such diffusion limited aggregation (DLA). In this work we have analyzed the structure of nanoparticles agglomerates in situ by means of Spin-Echo Small-Angle Neutron Scattering (SESANS), while they were fluidized in a gas stream. The advantage of SESANS over conventional SANS is that SESANS can measure scales up to 20 microns, while SANS does not exceed a few hundred of nanometers. We have observed that when agglomerates interact, their structure cannot be characterized by using only one scaling parameter, the fractal dimension. We have found that there are at least two structure levels in the agglomerates and hence, we need at least two parameters to describe the autocorrelation function in each level.

  18. Quantitative characterization of agglomerate abrasion in a tumbling blender by using the Stokes number approach.

    Science.gov (United States)

    Willemsz, Tofan A; Nguyen, Tien Thanh; Hooijmaijers, Ricardo; Frijlink, Henderik W; Vromans, Herman; van der Voort Maarschalk, Kees

    2013-03-01

    Removal of microcrystalline cellulose agglomerates in a dry-mixing system (lactose, 100 M) predominantly occurs via abrasion. The agglomerate abrasion rate potential is estimated by the Stokes abrasion (StAbr) number of the system. The StAbr number equals the ratio between the kinetic energy density of the moving powder bed and the work of fracture of the agglomerate. Basically, the StAbr number concept describes the blending condition of the dry-mixing system. The concept has been applied to investigate the relevance of process parameters on agglomerate abrasion in tumbling blenders. Here, process parameters such as blender rotational speed and relative fill volumes were investigated. In this study, the StAbr approach revealed a transition point between abrasion rate behaviors. Below this transition point, a blending condition exists where agglomerate abrasion is dominated by the kinetic energy density of the powder blend. Above this transition point, a blending condition exists where agglomerates show (undesirable) slow abrasion rates. In this situation, the blending condition is mainly determined by the high fill volume of the filler. PMID:23250711

  19. Biomass equipments. Dryers. Drying, crushing, agglomeration of agro-industrial products; Materiels pour la biomasse. Les secheurs, sechage, broyage, agglomeration de produits agro-industriels

    Energy Technology Data Exchange (ETDEWEB)

    Deur, O. [Promill (France)

    1997-12-31

    This paper describes the French Promill Company activity in the design and manufacturing of complete drying-crushing-agglomerating units for agro-industrial products (pulp of beet, lucerne, etc..). The paper focusses on the thermal and mechanical efficiency of the high temperature dryer and on the pulp granulating squeezer. (J.S.)

  20. Preparation of sustained release matrix pellets by melt agglomeration in the fluidized bed: influence of formulation variables and modelling of agglomerate growth.

    Science.gov (United States)

    Pauli-Bruns, Anette; Knop, Klaus; Lippold, Bernhard C

    2010-03-01

    The one-step preparation of sustained release matrix pellets, using a melting procedure in a fluidized bed apparatus, was tested in a 2(3) full factorial design of experiments, using microcrystalline wax as lipophilic binder, theophylline as model drug and talc as additional matrix forming agent. The three influence parameters were (A) size of binder particles, (B) fraction of theophylline in solid particles and (C) fraction of microcrystalline wax in formulation. The response variables were agglomerate size and size distribution, dissolution time, agglomerate crush resistance, sphericity, yield and porosity. Nearly spherical pellets comprising a smooth, closed surface could be obtained with the used method, exhibiting the hollow core typical for the immersion and layering mechanism. The reproducibility was very good concerning all responses. The size of agglomerates is proportional to the size of the binder particles, which serve as cores for pellet formation in the molten state in the fluidized bed. Additionally, the agglomerate size is influenced by the volume of the solid particles in relation to the binder particles, with more solid particles leading to larger agglomerates and vice versa. Dissolution times vary in a very wide range, resulting from the interplay between amount of drug in relation to the meltable matrix substance microcrystalline wax and the non-meltable matrix substance talc. The change of binder particle size does not lead to a structural change of the matrix; both dissolution times and porosity are not significantly altered. Agglomerate crush resistance is low due to the hollow core of the pellets. However, it is significantly increased if the volume fraction of microcrystalline wax in the matrix is high, which means that the matrix is mechanically better stabilized. A theoretical model has been established to quantitatively explain agglomerate growth and very good accordance of the full particle size distributions between predicted and

  1. THE EFFECT OF OFFSET PRINTING INK ON LASER TONER INK AGGLOMERATION UNDER NEUTRAL PULPING CONDITIONS

    Directory of Open Access Journals (Sweden)

    Sujin Xie,

    2012-05-01

    Full Text Available 1-octadecanol is known to be a highly effective agglomerating agent for laser toner ink. However, the office waste paper used in the actual production often contains various types of inks. The effect of the offset ink and types of surfactants with different charge characteristics were studied relative to the agglomeration of the laser toner ink under neutral pulping conditions. It was found that the addition of a small amount of the offset ink printed waste paper was beneficial for the agglomeration of the laser toner ink. The optimal percentage of addition is 12.5% to 25%. The offset printed ink had a positive charge of 0.001±0.0005 mEq/g when the offset ink was treated by 70˚C water at neutral conditions. Addition of a proper amount of cationic surfactant was beneficial to improve the agglomeration at any ratio of the mixed laser printed and offset waste papers. When the percentage of offset waste paper was less than 50%, the addition of anionic surfactant and nonionic surfactant was harmful for agglomeration, and there was no significant effect at higher offset content.

  2. Effect of Rubber Nanoparticle Agglomeration on Properties of Thermoplastic Vulcanizates during Dynamic Vulcanization

    Directory of Open Access Journals (Sweden)

    Hanguang Wu

    2016-04-01

    Full Text Available We previously reported that the dispersed rubber microparticles in ethylene-propylene-diene monomer (EPDM/polypropylene (PP thermoplastic vulcanizates (TPVs are actually agglomerates of rubber nanoparticles. In this study, based on this new understanding of the microstructure of TPV, we further revealed the microstructure-properties relationship of EPDM/PP TPV during dynamic vulcanization, especially the effect of the size of rubber nanoparticle agglomerates (dn, the thicknesses of PP ligaments (IDpoly and the rubber network on the properties of EPDM/PP TPV. We were able to simultaneously obtain a high tensile strength, elongation at break, elastic modulus, and elasticity for the EPDM/PP TPV by the achievement of a smaller dn, a thinner IDpoly and a denser rubber network. Interestingly, the effect of dn and IDpoly on the elastic modulus of EPDM/PP TPV composed of rubber nanoparticle agglomerates is different from that of EPDM/PP TPVs composed of rubber microparticles reported previously. The deformation behavior of the TPVs during stretching was studied to understand the mechanism for the achievement of good mechanical properties. Interestingly, the rubber nanoparticle agglomerates are oriented along the tensile direction during stretching. The TPV samples with smaller and more numerous rubber nanoparticle agglomerates can slow down the development of voids and cracks more effectively, thus leading to increase in tensile strength and elongation at break of the EPDM/PP TPV.

  3. Morphological characterization of diesel soot agglomerates based on the Beer–Lambert law

    International Nuclear Information System (INIS)

    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. (paper)

  4. Possible ways of suppression of agglomeration of particles in fluidized bed combustion of selected waste biomass fuels

    International Nuclear Information System (INIS)

    Fluidized bed combustion (FBC) of biomass is often complicated by agglomeration of particles within the bed. The alkali compounds from biomass ash have tendency to accumulate esp. in a bed with sand particles. For typical cases of FBC of straw, wood and sewage sludge from a paper mill the experimental results on fluidized bed particle agglomeration are presented and possible ways for agglomeration abatement are critically assessed (author)

  5. The impact of agglomeration and storage on flavor and flavor stability of whey protein concentrate 80% and whey protein isolate.

    Science.gov (United States)

    Wright, B J; Zevchak, S E; Wright, J M; Drake, M A

    2009-01-01

    The impact of agglomeration on flavor and flavor stability of whey protein concentrates 80% (WPC80) and whey protein isolates (WPI) has not been widely addressed. This study examined the impact of agglomeration on the flavor and flavor stability of commercial WPC80 and WPI across 18 mo of storage. Duplicate agglomerated and nonagglomerated WPC80 and WPI were collected from 4 facilities and stored at 21 degrees C, 50% relative humidity. Volatile analysis using solid phase microextraction (SPME) with gas chromatography-mass spectrometry (GC-MS) and descriptive sensory analysis were conducted every 2 mo. Solubility index, bulk volume, dispersibility, moisture, and color (L, a, b) were tested every 3 or 6 mo. Consumer acceptance testing with protein beverages was conducted with fresh and stored whey proteins. Higher intensities and more rapid development of lipid oxidation flavors (cardboard, raisin/brothy, cucumber, and fatty) were noted in agglomerated powders compared to nonagglomerated powders (P agglomerated products compared to nonagglomerated powders (P agglomerated WPC80 stored for 12 mo and agglomerated or nonagglomerated WPI stored for 18 mo compared to fresh products while trained panelists detected differences among beverages and rehydrated proteins earlier. Agglomeration with or without lecithin decreased the storage stability of whey proteins. These results indicate that the optimum shelf life at 21 degrees C for nonagglomerated whey proteins is 12 to 15 mo and 8 to 12 mo for agglomerated whey proteins. PMID:19200117

  6. THE EFFECT OF CHARGE AND CHEMICAL STRUCTURE OF CATIONIC SURFACTANTS ON LASER TONER AGGLOMERATION UNDER ALKALINE PULPING CONDITIONS

    Directory of Open Access Journals (Sweden)

    Jie Jiang,

    2012-02-01

    Full Text Available Laboratory-scale agglomeration experiments followed by image analysis were used to evaluate the effectiveness of different cationic surfactants on the 1-octadecanol agglomeration of a negatively charged laser toner. Various types of surfactants with different geometric structures were investigated. It was found that this toner became agglomerated under neutral pulping conditions, but it did not agglomerate under alkaline conditions at all. A small amount of the cationic surfactant compensated for the agglomeration disruption caused by the negative surface charge of the toner and made this toner agglomerate very well. These cationic surfactants consist of a chemical structure of C12 to C18 saturated alkyl hydrophobic chains. The positive charge of these surfactants played the major role in alleviating agglomeration disruption. Additionally, an extra phenol group on these surfactants contributed only minor advantages for toner agglomeration in the presence of 1-octadecanol. The best co-agglomeration performance occurred within a very narrow range of similar total positive charge densities based on the total toner weight. It was also found that this positive charge effect could not be applied to the chemical compounds of high molecular weight polymeric materials.

  7. Bed material agglomeration during fluidized bed combustion. Technical progress report, January 1, 1995--March 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-04-01

    Experiments performed support the hypothesis that a reducing atmosphere during fluidized bed coal combustion contributes to the formation of agglomerates. Reducing conditions are imposed by controlling the amount of combustion air supplied to the combustor, 50% of theoretical in these experiments. These localized reducing conditions may arise from either poor lateral bed mixing or oxygen-starved conditions due to the coal feed locations. Deviations from steady-state operating conditions in bed pressure drop may be used to detect agglomerate formation. Interpretation of the bed pressure drop was made more straightforward by employing a moving average difference method. During steady-state operation, the difference between the moving point averages should be close to zero, within {plus_minus}0.03 inches of water. Instability within the combustor, experienced once agglomerates begin to form, can be recognized as larger deviations from zero, on the magnitude of {plus_minus}0.15 inches of water.

  8. Effect of whey protein agglomeration on spray dried microcapsules containing Saccharomyces boulardii.

    Science.gov (United States)

    Duongthingoc, Diep; George, Paul; Katopo, Lita; Gorczyca, Elizabeth; Kasapis, Stefan

    2013-12-01

    This work investigates the effect of whey protein agglomeration on the survivability of Saccharomyces boulardii within spray dried microcapsules. It attempts to go beyond phenomenological observations by establishing a relationship between physicochemical characteristics of the polymeric matrix and its effect on probiotic endurance upon spray drying. It is well known that this type of thermal shock has lethal consequences on the yeast cells. To avoid such undesirable outcome, we take advantage of the early agglomeration phenomenon observed for whey protein by adjusting the pH value of preparations close to isoelectric point (pH 4-5). During the subsequent process of spray drying, development of whey protein agglomerates induces formation of an early crust, and the protein in this molten globular state creates a cohesive network encapsulating the yeast cells. It appears that the early crust formation at a given sample pH and temperature regime during spray drying benefits the survivability of S. boulardii within microcapsules. PMID:23870891

  9. On the Mechanism of Ultrasound-Driven Deagglomeration of Nanoparticle Agglomerates in Aluminum Melt

    Science.gov (United States)

    Kudryashova, Olga; Vorozhtsov, Sergey

    2016-05-01

    One of the promising directions in the technology of composite alloys with improved mechanical properties is reinforcement of the metallic matrix with nanopowders introduced in the liquid metal. Ultrasonic processing is known to significantly improve the introduction of submicrone particles to the metallic melt. This study focuses on the mechanisms of deagglomeration and wettability of such particles by the melt under the action of ultrasound. The suggested mechanism involves the penetration of the liquid metal into the pores and cracks of the agglomerates under the excess pressure created by imploding cavitation bubbles and further destruction of the agglomerate by the sound wave. The main dependences connecting the acoustic parameters and processing time with the physical and chemical properties of particles and the melt are obtained through analytical modeling. The mathematical description of the ultrasonic deagglomeration in liquid metal is presented; a dependence of the threshold intensity of ultrasound for the break-up of agglomerates on their size is reported.

  10. Distribution Characteristics and Compressibility of Agglomerates as a Reflection of Granulation Parameters

    Directory of Open Access Journals (Sweden)

    Macho Oliver

    2015-12-01

    Full Text Available Selective adjustment of the properties of particular material agglomeration has its inherent place in the chemical, food, but especially in the pharmaceutical, industry. The requirement to produce an agglomerate with desired particle size at a given strength is often formulated. To create the targeted product, it is necessary to know the process parameters affecting the preparation of its features. This paper deals with survey distribution characteristics and compressibility changes of an agglomerate in dependence on the duration of the granulation process through the usage of the most modern devices working with particulate materials. The investigated product will be prepared for coating granulating disc designed at the Institute of Process Engineering, Faculty of Mechanical Engineering, Slovak University of Technology in Bratislava.

  11. Internal migration, regional labor markets and the role of agglomeration economies

    DEFF Research Database (Denmark)

    Mitze, Timo Friedel; Schmidt, Torben Dall

    2015-01-01

    economies are indeed key drivers of internal migration flows in Denmark. That is, while we obtain mixed evidence with regard to the role of traditional labor and housing market variables, most of the included proxies for agglomeration economies such as the region’s population density, patent intensity......We analyze the determinants and regional implications of internal migration flows across Danish municipalities in 2006–2012. Besides assessing the role of labor market and housing market factors in driving a region’s net migration rate, we particularly focus on agglomeration factors identified by...... for the role of space–time dynamic adjustment processes and simultaneity among migration and labor market variables and finally test for heterogeneity in the migration response to regional labor market disparities among low- and high-skilled migrants. Our results support the view that agglomeration...

  12. CRYSTALLO-CO-AGGLOMERATION: A NOVEL TECHNIQUE TO IMPROVE FLOW AND COMPRESSIBILITY

    Directory of Open Access Journals (Sweden)

    Nikita B Rahate

    2013-07-01

    Full Text Available Crystallo-co-agglomeration is a particle design technique in which a drug is crystallized and agglomerated with an excipient or another drug, which may or may not be crystallized in same system. The various parameters optimized were type, amount and mode of addition of bridging liquid, temperature and agitation speed. They were characterized for micrometritic properties (particle size and shape, flowability, packability, bulk density, wettability and compressibility. The prepared spherical crystals with different polymers exhibited excellent physicochemical properties like flowability, pack ability and wettability compared with the pure drug. The process is simple and inexpensive enough for scaling upto a commercial level. It reduces time and cost by enabling faster operation, less machinery and fewer personnel. Keywords: Crystallo-co-agglomeration, flowability, compressibility, bioavailability.

  13. Effect of agglomeration during coprecipitation: Delayed spinellization of magnesium aluminate hydrate

    Indian Academy of Sciences (India)

    Soumen Pal; A K Bandyopadhyay; S Mukherjee; B N Samaddar; P G Pal

    2010-08-01

    Precipitation of magnesium aluminate hydrate with faster addition of ammonia at desired pH causes agglomeration. Agglomerated powder, without any further treatment, on calcination forms intermediate compounds at low temperatures (≤ 900°C). The intermediate compounds on further heat treatment (≥ 1000°C) decompose into MgO, MgAl2O4 and -Al2O3. Effect of agglomeration and absorption of foreign ions such as Cl–, SO$^{2-}_{4}$, and NH$^{+}_{4}$ in complex compounds probably cause loss of Al3+ and Mg2+ ions during heat treatment, and stoichiometry changes. Powders prepared by continuous method with better control of process parameters than batch process yields better spinellization.

  14. FORMATION MECHANISM AND SPATIAL PATTERN OF URBAN AGGLOMERATION IN CENTRAL JILIN OF CHINA

    Institute of Scientific and Technical Information of China (English)

    QIN Gan; ZHANG Ping-yu; JIAO Bin

    2006-01-01

    Urban agglomeration is made up of cities with different sizes to be linked by traffic network in a given area, and it is an inevitable result when urbanization reaches a certain level. Taking urban agglomerationin central Jilin(UACJ) as an example, this article analyzes the formation mechanism and spatial pattern of urban agglomeration in the less-developed area. First, the dynamics of UACJ has been analyzed from the aspects of geographical condition, economic foundation, policy background, and traffic condition. Then the development process is divided into three stages-single city, city group and city cluster. Secondly, the central cities are identified from the aspects of city centrality, and the development axes are classified based on economic communication capacity. Finally, the urban agglomeration is divided into five urban economic regions in order to establish the reasonable distribution of industries.

  15. Mathematical modeling of pigment dispersion taking into account the full agglomerate particle size distribution

    DEFF Research Database (Denmark)

    Kiil, Søren

    2016-01-01

    particle size distribution was simulated. Data from two previous experimental investigations were used for model validation. The first concerns two different yellow organic pigments dispersed in nitrocellulose/ethanol vehicles in a ball mill and the second a red organic pigment dispersed in a solvent...... only adjustable parameter used was an apparent rate constant for the linear agglomerate erosion rate. Model simulations, at selected values of time, for the full agglomerate particle size distribution were in good qualitative agreement with the measured values. A quantitative match of the experimental...... particle size distributions could be obtained using time-dependent fragment distributions, but this resulted in a very slight improvement in the simulated transient mean diameter only. The model provides a mechanistic understanding of the agglomerate breakage process that can be used, e.g., in the...

  16. Combined deterministic-stochastic framework for modeling the agglomeration of colloidal particles.

    Science.gov (United States)

    Mortuza, S M; Kariyawasam, Lahiru K; Banerjee, Soumik

    2015-07-01

    We present a multiscale model, based on molecular dynamics (MD) and kinetic Monte Carlo (kMC), to study the aggregation driven growth of colloidal particles. Coarse-grained molecular dynamics (CGMD) simulations are employed to detect key agglomeration events and calculate the corresponding rate constants. The kMC simulations employ these rate constants in a stochastic framework to track the growth of the agglomerates over longer time scales and length scales. One of the hallmarks of the model is a unique methodology to detect and characterize agglomeration events. The model accounts for individual cluster-scale effects such as change in size due to aggregation as well as local molecular-scale effects such as changes in the number of neighbors of each molecule in a colloidal cluster. Such definition of agglomeration events allows us to grow the cluster to sizes that are inaccessible to molecular simulations as well as track the shape of the growing cluster. A well-studied system, comprising fullerenes in NaCl electrolyte solution, was simulated to validate the model. Under the simulated conditions, the agglomeration process evolves from a diffusion limited cluster aggregation (DLCA) regime to percolating cluster in transition and finally to a gelation regime. Overall the data from the multiscale numerical model shows good agreement with existing theory of colloidal particle growth. Although in the present study we validated our model by specifically simulating fullerene agglomeration in electrolyte solution, the model is versatile and can be applied to a wide range of colloidal systems. PMID:26274304

  17. Agglomeration in Stripper Ash Coolers and Its Possible Remedial Solutions: a Case Study

    Science.gov (United States)

    Singh, Ravi Inder

    2016-04-01

    The bottom ash of circulating fluidized bed (CFB) boiler contains large amounts of physical heat. When low quality coals are used in these types of boilers, the ash content is normally more than 40 % and the physical heat loss is approximately 3 % if the bottom ash is discharged without cooling. Bottom ash cooler (BAC) is often used to treat the high temperature bottom ash to reclaim heat, and to facilitate the easily handling and transportation of ash. The CFB boiler at BLA Power, Newari, MP (India) is facing problems of clinker formation in strip ash coolers of plant since the installation of unit. These clinkers are basically agglomerates, which leads to defluidization of stripper ash cooler (BAC) units. There are two strip ash coolers in unit. Each strip ash cooler is capable of working independently. The proper functioning of both strip coolers is very important as it is going to increase the combustion efficiency of boiler by stripping of fine unburnt coal particles from ash, which are injected into the furnace. In this paper causes, characterization of agglomerates, thermo gravimetric analysis of fuel used, particular size distribution of coal and sand and possible remedial solution to overcome these agglomerates in strip ash coolers has also been presented. High temperature in compact separators, non uniform supply of coal and not removing small agglomerates from stripper ash cooler are among main causes of agglomeration in stripper ash cooler. Control of compact separator temperature, replacing 10-12 % of bed material and cleaning stripper ash cooler periodically will decrease agglomeration in stripper ash cooler of unit.

  18. The Morphology of Urban Agglomerations for Developing Countries: A Case Study with China

    CERN Document Server

    Gangopadhyay, Kausik

    2010-01-01

    In this article, the relationship between two well-accepted empirical propositions regarding the distribution of population in cities, namely, Gibrat's law and Zipf's law, are rigorously examined using the Chinese census data. Our findings are quite in contrast with the most of the previous studies performed exclusively for developed countries. This motivates us to build a general environment to explain the morphology of urban agglomerations both in developed and developing countries. A dynamic process of job creation generates a particular distribution for the urban agglomerations and introduction of Special Economic Zones (SEZ) in this abstract environment shows that the empirical observations are in good agreement with the proposed model.

  19. Detailed analysis of a quench bomb for the study of aluminum agglomeration in solid propellants

    Science.gov (United States)

    Gallier, S.; Kratz, J.-G.; Quaglia, N.; Fouin, G.

    2016-07-01

    A standard quench bomb (QB) - widely used to characterize condensed phase from metalized solid propellant combustion - is studied in detail. Experimental and numerical investigations proved that collected particles are mostly unburned aluminum (Al) agglomerates despite large quenching distances. Particles are actually found to quench early as propellant surface is swept by inert pressurant. Further improvements of the QB are proposed which allow measuring both Al agglomerates and alumina residue with the same setup. Finally, the results obtained on a typical aluminized ammonium perchlorate (AP) / hydroxyl-terminated polybutadiene (HTPB) propellant are briefly discussed.

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

    Science.gov (United States)

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

    2014-10-01

    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.

  1. Direct numerical simulations of agglomeration of circular colloidal particles in two-dimensional shear flow

    Science.gov (United States)

    Choi, Young Joon; Djilali, Ned

    2016-01-01

    Colloidal agglomeration of nanoparticles in shear flow is investigated by solving the fluid-particle and particle-particle interactions in a 2D system. We use an extended finite element method in which the dynamics of the particles is solved in a fully coupled manner with the flow, allowing an accurate description of the fluid-particle interfaces without the need of boundary-fitted meshes or of empirical correlations to account for the hydrodynamic interactions between the particles. Adaptive local mesh refinement using a grid deformation method is incorporated with the fluid-structure interaction algorithm, and the particle-particle interaction at the microscopic level is modeled using the Lennard-Jones potential. Motivated by the process used in fabricating fuel cell catalysts from a colloidal ink, the model is applied to investigate agglomeration of colloidal particles under external shear flow in a sliding bi-periodic Lees-Edwards frame with varying shear rates and particle fraction ratios. Both external shear and particle fraction are found to have a crucial impact on the structure formation of colloidal particles in a suspension. Segregation intensity and graph theory are used to analyze the underlying agglomeration patterns and structures, and three agglomeration regimes are identified.

  2. Agglomeration, Innovation and Regional Development: Theoretical Perspectives and Meta-Analysis

    NARCIS (Netherlands)

    Groot, de Henri L.F.; Poot, Jacques; Smit, Martijn J.

    2007-01-01

    Innovation and technological change are central to the quest for regional development. In the globally-connected knowledge-driven economy, the relevance of agglomeration forces that rely on proximity continues to increase, paradoxically despite declining real costs of information, communication and

  3. Evidence of zirconium nano-agglomeration in as-cast dilute U–Zr alloys

    International Nuclear Information System (INIS)

    Microstructure evaluation of as-cast and annealed U–Zr (Zr = 2, 6 and 10 wt.%) alloys has been carried out for the first time using positrons as a probe. The chemical signature in the matter–antimatter annihilation gamma and the positron lifetime data suggests that majority of positrons are annihilating from Zr sites in the as-cast alloys. The results have been interpreted as due to the presence of Zr nano-agglomerates in the as-cast alloys which have a higher positron affinity as compared to the rest of the U matrix. A minimum agglomerate size of ∼2 nm diameter has been calculated from the difference in positron affinity between the agglomerates and the matrix. Upon annealing, the Zr signature in the annihilation gamma photons vanishes suggesting that the Zr agglomerates diffuse out of U matrix and form micron-sized precipitates. This has been confirmed by scanning electron microscopy which shows a 3 times increase in the surface density of the precipitates in the annealed alloys as compared to the as-cast ones. Shorter positron diffusion length (measured using slow positron beam) as compared to precipitate separation has been invoked to explain the observed data

  4. Interaction between magnetic agglomerates and an extended free radicals network studied by magnetic resonance

    Science.gov (United States)

    Guskos, Niko; Zolnierkiewicz, Grzegorz; Typek, Janusz; Guskos, Aleksander; Berczynski, Pawel; Petridis, Dimitri

    2012-02-01

    Solids containing an extended network of free radicals have been prepared and studied by magnetic resonance techniques in the 4-290 K temperature range. One solid contained additionally a small amount of magnetic γ-Fe2O3 in the form of nanoparticle agglomerates. The solid without agglomerates displayed only a narrow, single resonance line centered at g eff = 2.0043. The magnetic resonance measurements of the solid with γ-Fe2O3 agglomerates gave a spectrum composed of two lines attributed to two different magnetic centers: a narrow line due to free radicals and a broad line arising from magnetic iron oxide agglomerates. In the high temperature range the integrated intensities of both lines decreased with decreasing temperature. The resonance field of the broad line shifted to lower magnetic fields upon lowering the temperature with the gradient ΔH r/ΔT = 2.3 G/K, while the narrow line shifted towards higher magnetic fields. The linewidth of the broader line increased with decreasing temperature while for the narrow lines in both samples this change was small. The magnetic iron oxide clusters produce a magnetic field which acts on the free radicals network and its strength depends essentially on the concentration of clusters. The reorientation process in the free radicals network is more intense in the sample without magnetic clusters.

  5. The influence of lisping material in pelletizing and agglomeration of fine coal pieces in laboratory conditions

    International Nuclear Information System (INIS)

    The work presents a part of laboratory results realized in academy of Friburg, carried on pelletizing and agglomeration of waste material, fine coal from thermal power station, using different lisping materials. Specially the influence of these materials in getting solid fuel, small briquette, formed by rolling press is analyzed. Special interest is attended to their characteristics: hardness and resistance. (Author)

  6. The influence of lisping material in pelletizing and agglomeration of fine coal pieces in laboratory conditions

    International Nuclear Information System (INIS)

    The work presents a part of laboratory results realized in academy of Firebug, carried on pelletizing and agglomeration of waste material, fine coal from thermal power station, using different lisping materials. Specially the influence of these materials in getting solid fuel, small briquette, formed by rolling press is analyzed. Special interest is attended to their characteristics: hardness and resistance. (Author)

  7. Cities in transition: monitoring growth trends in Delhi urban agglomeration 1991-2001

    OpenAIRE

    Debnath Mookherjee

    2004-01-01

    An analysis based on census data for the decade 1991-2001 indicates change in the urban structure of the Delhi Urban Agglomeration, India. The number and rate of growth of cen-sus towns and the urban core are examined. The pattern shows emerging traits of urban spread and provides an investigative framework for future research.

  8. Cities in transition: monitoring growth trends in Delhi urban agglomeration 1991-2001:

    OpenAIRE

    Debnath Mookherjee; Eugene Hoerauf

    2004-01-01

    An analysis based on census data for the decade 1991-2001 indicates change in the urbanstructure of the Delhi Urban Agglomeration, India. The number and rate of growth of censustowns and the urban core are examined. The pattern shows emerging traits of urbanspread and provides an investigative framework for future research.

  9. Cities in transition: monitoring growth trends in Delhi urban agglomeration 1991-2001

    Directory of Open Access Journals (Sweden)

    Debnath Mookherjee

    2004-12-01

    Full Text Available An analysis based on census data for the decade 1991-2001 indicates change in the urban structure of the Delhi Urban Agglomeration, India. The number and rate of growth of cen-sus towns and the urban core are examined. The pattern shows emerging traits of urban spread and provides an investigative framework for future research.

  10. Biomass ash-bed material interactions leading to agglomeration in FBC

    DEFF Research Database (Denmark)

    Visser, H.J.M.; van Lith, Simone Cornelia; Kiel, J.H.A.

    2008-01-01

    In (bubbling) fluidized-bed combustion and gasification of biomass, several potential problems are associated with the inorganic components of the fuel. A major problem area is defluidization due to bed agglomeration. The most common found process leading to defluidization in commercial-scale ins...

  11. Modelling Inter-Particle Forces and Resulting Agglomerate Sizes in Cement-Based Materials

    DEFF Research Database (Denmark)

    Kjeldsen, Ane Mette; Geiker, Mette Rica

    2005-01-01

    The theory of inter-particle forces versus external shear in cement-based materials is reviewed. On this basis, calculations on maximum agglomerate size present after the combined action of superplasticizers and shear are carried out. Qualitative experimental results indicate that external shear ...

  12. Direct numerical simulations of agglomeration of circular colloidal particles in two-dimensional shear flow

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Young Joon, E-mail: yjchoi@uvic.ca; Djilali, Ned, E-mail: ndjilali@uvic.ca [Institute for Integrated Energy Systems and Department of Mechanical Engineering, University of Victoria, Victoria, British Columbia V8W 3P6 (Canada)

    2016-01-15

    Colloidal agglomeration of nanoparticles in shear flow is investigated by solving the fluid-particle and particle-particle interactions in a 2D system. We use an extended finite element method in which the dynamics of the particles is solved in a fully coupled manner with the flow, allowing an accurate description of the fluid-particle interfaces without the need of boundary-fitted meshes or of empirical correlations to account for the hydrodynamic interactions between the particles. Adaptive local mesh refinement using a grid deformation method is incorporated with the fluid-structure interaction algorithm, and the particle-particle interaction at the microscopic level is modeled using the Lennard-Jones potential. Motivated by the process used in fabricating fuel cell catalysts from a colloidal ink, the model is applied to investigate agglomeration of colloidal particles under external shear flow in a sliding bi-periodic Lees-Edwards frame with varying shear rates and particle fraction ratios. Both external shear and particle fraction are found to have a crucial impact on the structure formation of colloidal particles in a suspension. Segregation intensity and graph theory are used to analyze the underlying agglomeration patterns and structures, and three agglomeration regimes are identified.

  13. Discrete element modelling of the quasi-static uniaxial compression of individual infant formula agglomerates

    Institute of Scientific and Technical Information of China (English)

    Kevin J. Hanley; Catherine O'Sullivan; Edmond P. Byrne; Kevin Cronin

    2012-01-01

    Infant formula is usually produced in an agglomerated powder form.These agglomerates are subjected to many transient forces following their manufacture.These can be difficult to quantify experimentally because of their small magnitudes and short durations.Numerical models have the potential to address this gap in the experimental data.The objective of the research described here was to calibrate a discrete element model for these agglomerates using experimental data obtained for quasi-static loading,and to use this model to study the mechanics of the particle response in detail.The Taguchi method was previously proposed as a viable calibration approach for discrete element models.In this work,the method was assessed for calibration of the model parameters (e.g.,bond stiffnesses and strengths) considering three responses: the force at failure,strain at failure and agglomerate stiffness.The Weibull moduli for the simulation results and the experimental data were almost identical following calibration and the 37% characteristic stresses were similar.An analysis of the energy terms in the model provided useful insight into the model response.The bond energy and the normal force exerted on the platens were strongly correlated,and bond breakage events coincided with the highest energy dissipation rates.

  14. A Comprehensive Quantitative Evaluation of New Sustainable Urbanization Level in 20 Chinese Urban Agglomerations

    Directory of Open Access Journals (Sweden)

    Cong Xu

    2016-01-01

    Full Text Available On 16 March 2014, the State Council of China launched its first urbanization planning initiative dubbed “National New Urbanization Planning (2014–2020” (NNUP. NNUP put forward 20 urban agglomerations and a sustainable development approach aiming to transform traditional Chinese urbanization to sustainable new urbanization. This study quantitatively evaluates the level of sustainability of the present new urbanization process in 20 Chinese urban agglomerations and provides some positive suggestions for the achievement of sustainable new urbanization. A three-level index system which is based on six fundamental elements in a city and a Full Permutation Polygon Synthetic Indicator evaluation method are adopted. The results show that China is undergoing a new urbanization process with a low level of sustainability and there are many problems remaining from traditional urbanization processes. There exists a polarized phenomenon in the urbanization of 20 urban agglomerations. Based on their own development patterns, the 20 urban agglomerations can be divided into seven categories. Every category has its own development characteristics. The analyses also show that waste of water resources, abuse of land resources, and air pollution are three big problems that are closely linked to traditional Chinese urbanization processes. To achieve sustainable new urbanization in China, four relevant suggestions and comments have been provided.

  15. Characterizing the dynamic behavior of nano-TiO2 agglomerates in suspensions by photocorrelation spectroscopy

    International Nuclear Information System (INIS)

    Metal oxide nanoparticles are small but easily form agglomerates in suspension, depending on the strength of particle–particle and particle–media interactions. To understand the agglomeration behavior of nanoparticles in media and relate to it to product performance testing, measurement methods are desired to characterize highly scattering metal oxide nanoparticle suspensions without dilution. In this article, we describe the advantages of using photocorrelation spectroscopy (PCS) in a backscattering detection configuration to carry out a realistic agglomerate size measurement in multiple scattering media found in most metal oxide nanoparticle suspensions. The dynamic behavior of nano-titanium dioxide (TiO2) particles in buffer solutions of different chemical composition and pH values was investigated as a sample system using PCS. The resulting autocorrelation functions (AFs) at different time intervals, particle concentrations, and pH values were measured at several detection angles. The AF exhibits a multi-mode relaxation time feature and the calculated hydrodynamic diameters strongly depended on media composition and detection angle. This result indicates that the size and dispersion of nano-TiO2 agglomerates are significantly affected by solution media. A measurement protocol for determining size and dispersion of metal oxide particles in media is proposed and related to a performance test found in industry.

  16. Dispersion of TiO2 Nanoparticle Agglomerates by Pseudomonas aeruginosa▿ †

    OpenAIRE

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

    2010-01-01

    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 aerugi...

  17. Transport and Deposition of Welding Fume Agglomerates in a Realistic Human Nasal Airway.

    Science.gov (United States)

    Tian, Lin; Inthavong, Kiao; Lidén, Göran; Shang, Yidan; Tu, Jiyuan

    2016-07-01

    Welding fume is a complex mixture containing ultra-fine particles in the nanometer range. Rather than being in the form of a singular sphere, due to the high particle concentration, welding fume particles agglomerate into long straight chains, branches, or other forms of compact shapes. Understanding the transport and deposition of these nano-agglomerates in human respiratory systems is of great interest as welding fumes are a known health hazard. The neurotoxin manganese (Mn) is a common element in welding fumes. Particulate Mn, either as soluble salts or oxides, that has deposited on the olfactory mucosa in human nasal airway is transported along the olfactory nerve to the olfactory bulb within the brain. If this Mn is further transported to the basal ganglia of the brain, it could accumulate at the part of the brain that is the focal point of its neurotoxicity. Accounting for various dynamic shape factors due to particle agglomeration, the current computational study is focused on the exposure route, the deposition pattern, and the deposition efficiency of the inhaled welding fume particles in a realistic human nasal cavity. Particular attention is given to the deposition pattern and deposition efficiency of inhaled welding fume agglomerates in the nasal olfactory region. For particles in the nanoscale, molecular diffusion is the dominant transport mechanism. Therefore, Brownian diffusion, hydrodynamic drag, Saffman lift force, and gravitational force are included in the model study. The deposition efficiencies for single spherical particles, two kinds of agglomerates of primary particles, two-dimensional planar and straight chains, are investigated for a range of primary particle sizes and a range of number of primary particles per agglomerate. A small fraction of the inhaled welding fume agglomerates is deposited on the olfactory mucosa, approximately in the range 0.1-1%, and depends on particle size and morphology. The strong size dependence of the deposition

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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 μm) 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 (μg/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

  19. A discrete element and ray framework for rapid simulation of acoustical dispersion of microscale particulate agglomerations

    Science.gov (United States)

    Zohdi, T. I.

    2016-03-01

    In industry, particle-laden fluids, such as particle-functionalized inks, are constructed by adding fine-scale particles to a liquid solution, in order to achieve desired overall properties in both liquid and (cured) solid states. However, oftentimes undesirable particulate agglomerations arise due to some form of mutual-attraction stemming from near-field forces, stray electrostatic charges, process ionization and mechanical adhesion. For proper operation of industrial processes involving particle-laden fluids, it is important to carefully breakup and disperse these agglomerations. One approach is to target high-frequency acoustical pressure-pulses to breakup such agglomerations. The objective of this paper is to develop a computational model and corresponding solution algorithm to enable rapid simulation of the effect of acoustical pulses on an agglomeration composed of a collection of discrete particles. Because of the complex agglomeration microstructure, containing gaps and interfaces, this type of system is extremely difficult to mesh and simulate using continuum-based methods, such as the finite difference time domain or the finite element method. Accordingly, a computationally-amenable discrete element/discrete ray model is developed which captures the primary physical events in this process, such as the reflection and absorption of acoustical energy, and the induced forces on the particulate microstructure. The approach utilizes a staggered, iterative solution scheme to calculate the power transfer from the acoustical pulse to the particles and the subsequent changes (breakup) of the pulse due to the particles. Three-dimensional examples are provided to illustrate the approach.

  20. A two dimensional agglomerate model for a proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    A two dimensional steady state and isothermal model of a proton exchange membrane fuel cell is presented. This model is applied to a fuel cell with a counter-flow mode of hydrogen and air along parallel flow channels. In the flow channel and porous media, reactant flow is modelled using the continuity and Navier–Stokes equation. Reactant diffusion and convection are modelled by the Maxwell–Stefan and Navier–Stokes equation, respectively. Water transport is described by the combined mechanism of electro-osmotic drag, back diffusion and hydraulic permeation. The catalyst layer is modelled as a spherical-agglomerate structure in which ionomer and liquid water partially occupy the void space to form a so-called carbon–ionomer–liquid water film inside the agglomerate. A mathematical relationship for the variation in film thickness with the current density is also developed. The effect of platinum and carbon loadings on the cell performance and effectiveness are simulated. The fuel cell polarisation curve based on the agglomerate with a film model gives good agreement to experimental data while the agglomerate without a film model overestimates the current density. The modelling results show that the rapid fall in current density at lower cell voltage is due to an increased oxygen diffusion resistance through the film. - Highlights: • An along channel 2D agglomerate model for a complete PEMFC unit is developed. • Liquid water film thickness (δ)–current density (i) relationship is developed. • δ is larger when higher current density and lower temperature applied. • δ is larger near cathode inlet and smaller near cathode outlet. • Oxygen diffusion rate is reduced by the liquid water film

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

    Science.gov (United States)

    Tantra, Ratna; Tompkins, Jordan; Quincey, Paul

    2010-01-01

    This paper describes the use of nanoparticle characterisation tools to evaluate the interaction between bovine serum albumin (BSA) and dispersed nanoparticles in aqueous media. Dynamic light scattering, zeta-potential measurements and scanning electron microscopy were used to probe the state of zinc oxide (ZnO) and titanium dioxide (TiO(2)) nanoparticles in the presence of various concentrations of BSA, throughout a three-day period. BSA was shown to adhere to ZnO but not to TiO(2). The adsorption of BSA led to subsequent de-agglomeration of the sub-micron ZnO clusters into smaller fragments, even breaking them up into individual isolated nanoparticles. We propose that certain factors, such as adsorption kinetics of BSA on to the surface of ZnO, as well as the initial agglomerated state of the ZnO, prior to BSA addition, are responsible for promoting the de-agglomeration process. Hence, in the case of TiO(2) we see no de-agglomeration because: (a) the nanoparticles are more highly agglomerated to begin with and (b) BSA does not adsorb effectively on the surface of the nanoparticles. The zeta-potential results show that, for either ZnO or TiO(2), the presence of BSA resulted in enhanced stability. In the case of ZnO, the enhanced stability is limited to BSA concentrations below 0.5 wt.%. Steric and electrostatic repulsion are thought to be responsible for improved stability of the dispersion. PMID:19775871

  2. Structural properties of silver nanoparticle agglomerates based on transmission electron microscopy: relationship to particle mobility analysis

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Weon Gyu; Wang Jing [University of Minnesota, Department of Mechanical Engineering (United States); Mertler, Michael; Sachweh, Bernd [Fine Particle Technology and Particle Characterization, BASF SE (Germany); Fissan, Heinz [Institute of Energy and Environmental Technology e. V. (IUTA) (Germany); Pui, David Y. H., E-mail: dyhpui@umn.ed [The University of Minnesota, Department of Mechanical Engineering (United States)

    2009-01-15

    In this work, the structural properties of silver nanoparticle agglomerates generated using condensation and evaporation method in an electric tube furnace followed by a coagulation process are analyzed using Transmission Electron Microscopy (TEM). Agglomerates with mobility diameters of 80, 120, and 150 nm are sampled using the electrostatic method and then imaged by TEM. The primary particle diameter of silver agglomerates was 13.8 nm with a standard deviation of 2.5 nm. We obtained the relationship between the projected area equivalent diameter (d{sub pa}) and the mobility diameter (d{sub m}), i.e., d{sub pa} = 0.92 {+-} 0.03 d{sub m} for particles from 80 to 150 nm. We obtained fractal dimensions of silver agglomerates using three different methods: (1) D{sub f} = 1.84 {+-} 0.03, 1.75 {+-} 0.06, and 1.74 {+-} 0.03 for d{sub m} = 80, 120, and 150 nm, respectively from projected TEM images using a box counting algorithm; (2) fractal dimension (D{sub fL}) = 1.47 based on maximum projected length from projected TEM images using an empirical equation proposed by Koylu et al. (1995) Combust Flame 100:621-633; and (3) mass fractal-like dimension (D{sub fm}) = 1.71 theoretically derived from the mobility analysis proposed by Lall and Friedlander (2006) J Aerosol Sci 37:260-271. We also compared the number of primary particles in agglomerate and found that the number of primary particles obtained from the projected surface area using an empirical equation proposed by Koylu et al. (1995) Combust Flame 100:621-633 is larger than that from using the relationship, d{sub pa} = 0.92 {+-} 0.03 d{sub m} or from using the mobility analysis.

  3. A new stochastic approach for the simulation of agglomeration between colloidal particles.

    Science.gov (United States)

    Henry, Christophe; Minier, Jean-Pierre; Pozorski, Jacek; Lefèvre, Grégory

    2013-11-12

    This paper presents a stochastic approach for the simulation of particle agglomeration, which is addressed as a two-step process: first, particles are transported by the flow toward each other (collision step) and, second, short-ranged particle-particle interactions lead either to the formation of an agglomerate or prevent it (adhesion step). Particle collisions are treated in the framework of Lagrangian approaches where the motions of a large number of particles are explicitly tracked. The key idea to detect collisions is to account for the whole continuous relative trajectory of particle pairs within each time step and not only the initial and final relative distances between two possible colliding partners at the beginning and at the end of the time steps. The present paper is thus the continuation of a previous work (Mohaupt M., Minier, J.-P., Tanière, A. A new approach for the detection of particle interactions for large-inertia and colloidal particles in a turbulent flow, Int. J. Multiphase Flow, 2011, 37, 746-755) and is devoted to an extension of the approach to the treatment of particle agglomeration. For that purpose, the attachment step is modeled using the DLVO theory (Derjaguin and Landau, Verwey and Overbeek) which describes particle-particle interactions as the sum of van der Waals and electrostatic forces. The attachment step is coupled with the collision step using a common energy balance approach, where particles are assumed to agglomerate only if their relative kinetic energy is high enough to overcome the maximum repulsive interaction energy between particles. Numerical results obtained with this model are shown to compare well with available experimental data on agglomeration. These promising results assert the applicability of the present modeling approach over a whole range of particle sizes (even nanoscopic) and solution conditions (both attractive and repulsive cases). PMID:24111685

  4. CONSOLIDATION OF K BASIN SLUDGE DATA AND EXPERIENCES ON AGGLOMERATE FORMATION

    International Nuclear Information System (INIS)

    The formation of high sludge strength agglomerates is a key concern to the Sludge Treatment Project (STP) to ensure the sludge can be retrieved after planned storage for up to 10 years in Sludge Transport and Storage Containers (STSC) at T Plant. This report addresses observations of agglomerate formation, conditions that the data shows lead to agglomeration, the frequency of agglomerate formation and postulated physiochemical mechanisms that may lead to agglomeration. Although the exact underlying chemistry of K Basin sludge agglomerate formation is not known, the factors that lead to agglomeration formation, based on observations, are as follows: (1) High Total Uranium Content (i.e., sample homogeneity and influence from other constituents); (2) Distribution of Uranium Phases (i.e., extent of conversion from uraninite to uranium oxide hydroxide compounds); (3) Sample Dry-out (loss of cover water); (4) Elevated temperature; (5) Solubility ofU(IV) phases vs. U(VI) phases; and (6) Long storage times. Agglomerated sludge has occurred infrequently and has only been observed in four laboratory samples, five samples subjected to hydrothermal testing (performed for 7 to 10 hours at ∼185 C and 225 psig), and indirectly during six sampling events in the KE Basin. In the four laboratory samples where agglomerates were observed, the agglomerates exhibited high shear strength and the sample container typically had to be broken to remove the solids. The total uranium content (dry basis) for the four samples (KE Pit, KC-2/3 SS, KC-2/3 M250 and 96-13) were ∼8 wt%, ∼59.0 wt%, 68.3 wt% and 82 wt%. The agglomerates that were present during the six sampling events were undoubtedly disturbed and easily broken apart during sample collection, thus no agglomerates were observed in subsequent laboratory analyses. The highest shear strengths measured for K Basin sludge samples were obtained after hydrothermal treatment (7 to 10 hr at 185 C) of high-uranium-content KE canister sludge

  5. CONSOLIDATION OF K BASIN SLUDGE DATA AND EXPERIENCES ON AGGLOMERATE FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    HILL SR

    2010-06-10

    The formation of high sludge strength agglomerates is a key concern to the Sludge Treatment Project (STP) to ensure the sludge can be retrieved after planned storage for up to 10 years in Sludge Transport and Storage Containers (STSC) at T Plant. This report addresses observations of agglomerate formation, conditions that the data shows lead to agglomeration, the frequency of agglomerate formation and postulated physiochemical mechanisms that may lead to agglomeration. Although the exact underlying chemistry of K Basin sludge agglomerate formation is not known, the factors that lead to agglomeration formation, based on observations, are as follows: (1) High Total Uranium Content (i.e., sample homogeneity and influence from other constituents); (2) Distribution of Uranium Phases (i.e., extent of conversion from uraninite to uranium oxide hydroxide compounds); (3) Sample Dry-out (loss of cover water); (4) Elevated temperature; (5) Solubility ofU(IV) phases vs. U(VI) phases; and (6) Long storage times. Agglomerated sludge has occurred infrequently and has only been observed in four laboratory samples, five samples subjected to hydrothermal testing (performed for 7 to 10 hours at {approx}185 C and 225 psig), and indirectly during six sampling events in the KE Basin. In the four laboratory samples where agglomerates were observed, the agglomerates exhibited high shear strength and the sample container typically had to be broken to remove the solids. The total uranium content (dry basis) for the four samples (KE Pit, KC-2/3 SS, KC-2/3 M250 and 96-13) were {approx}8 wt%, {approx}59.0 wt%, 68.3 wt% and 82 wt%. The agglomerates that were present during the six sampling events were undoubtedly disturbed and easily broken apart during sample collection, thus no agglomerates were observed in subsequent laboratory analyses. The highest shear strengths measured for K Basin sludge samples were obtained after hydrothermal treatment (7 to 10 hr at 185 C) of high-uranium-content KE

  6. An Empirical Analysis of Industrial Agglomeration in the Western Ethnic Region

    Institute of Scientific and Technical Information of China (English)

    HE Xionglang; ZHANG Huiyin

    2014-01-01

    Industrial agglomeration refers to a high concentration of the same industry or related industries in a particular geographic area , and a process of gradual concentration of industrial cap-ital elements within a space .The new economic geography considers that industrial agglomeration is caused by circulating cumulative cause and effect . Accidental disturbance destroys the original bal-ance of the symmetrical area , which in turn brings about the expansion of the market in a concentrated industrial area , which then causes the effect of market expansion.This, accordingly, induces the factors of production to begin to concentrate in the area.The concentration of elements and industries brings about the “regional price index effect”.The concentration of manufacturers in the region is helpful in reducing both transportation costs and living costs of the labor .Accordingly , the elements become further concentrated , which causes the ex-pansion of market scale and the concentration of el-ements.Finally, a kind of industrial agglomeration forms.Industrial agglomeration is not only a kind of group concentration of similar enterprises in a specific region , but most importantly it is a kind of common growth among the enterprises .Therefore, the degree of concentration of an industry reflects the competiveness of an industry , which in turn re-flects the economic strength of a region or a coun-try.The concept that industrial concentration could promote the relative competiveness of the industries in the region has already been accepted by most e-conomists .Hence , it has an important meaning re-garding the study of industrial agglomeration in the western ethnic region . There are two ways to measure industrial ag-glomeration.One is the Gini Coefficient index and the other is the Industrial Agglomeration Index of location quotient .The author thinks that the degree of regional industrial agglomeration could either be examined with a static stock index , or a dynamic

  7. The characteristics of bed agglomeration/defluidization in fluidized bed firing palm fruit bunch and rice straw

    International Nuclear Information System (INIS)

    The behaviors of bed particle agglomeration and defluidization were investigated during the combustion of oil palm bunch and rice straw in a laboratory scale bubbling fluidized bed reactor. The study focused on (1) the effects of fuel inorganic properties and operating variables on the bed agglomeration tendency and (2) the elucidation in the behaviors of fuel inorganic elements and the governing mode of the agglomeration. It was experimentally found that the defluidization caused by the bed agglomeration was clearly detectable from the decrease of measured bed pressure. The accumulation and growth of the agglomerates provided the partial to complete defluidization. The fuel inorganic composition was the significant influence on the bed agglomeration. The combustion of palm bunch showed higher in the bed agglomeration tendency than the straw combustion in every experimental condition. The defluidization was accelerated in response to the increase in bed temperature and bed particle size, and the decrease of air velocity and static bed height. In the SEM/EDS analysis, the agglomeration was attributed to the formation of the molten substance rich in silicon and fuel derived potassium, likely the potassium silicate compounds, which presented as the adhesive coating and bonding layer. The filling of irregularity on the bed particle surface by the liquid material to form the adhesive layer was dominated by the collision with burning fuel particles. The propagation/reaction inward the bed particles by some reactive constituents was found. The thermodynamic analysis on the ternary phase diagram corroborated that the formation of the liquid material derived from the fuel inorganic elements controlled the agglomeration; the large melt fraction in the adhesive materials at the observed bed temperature range (62–99%) was estimated. - Highlights: • The bed agglomeration was investigated during the FBC of palm bunch and rice straw. • Bed temperature, sand size, air

  8. An SEM/EDX study of bed agglomerates formed during fluidized bed combustion of three biomass fuels

    International Nuclear Information System (INIS)

    The agglomeration behaviour of three biomass fuels (exhausted and virgin olive husk and pine seed shells) during fluidized bed combustion in a lab-scale reactor was studied by means of SEM/EDX analysis of bed agglomerate samples. The effect of the fuel ash composition, bed temperature and sand particle size on agglomeration was investigated. The study was focused on the main fuel ash components and on their interaction with the bed sand particles. Agglomeration was favoured by high temperature, small sand size, a high fraction of K and Na and a low fraction of Ca and Mg in the fuel ash. An initial fuel ash composition close to the low-melting point eutectic composition appears to enhance agglomeration. The agglomerates examined by SEM showed a hollow structure, with an internal region enriched in K and Na where extensive melting is evident and an external one where sand particles are only attached by a limited number of fused necks. Non-molten or partially molten ash structures deposited on the sand surface and enriched in Ca and Mg were also observed. These results support an ash deposition-melting mechanism: the ash released by burning char particles inside the agglomerates is quantitatively deposited on the sand surface and then gradually embedded in the melt. The low-melting point compounds in the ash migrate towards the sand surface enriching the outermost layer, while the ash structure is progressively depleted of these compounds

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-11-15

    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.

  10. Tests of Bed Agglomeration Tendency Using a Rotating Furnace; Roterugn foer bedoemning av sintringsbenaegenhet

    Energy Technology Data Exchange (ETDEWEB)

    Larfeldt, Jenny; Zintl, Frank [TPS Termiska Processer AB, Nykoeping (Sweden)

    2003-08-01

    Bed sintering is a well known problem in fluidised bed boilers. In order to avoid bed sintering the bed material turn over ratio is high which leads a high consumption of bed material. This work aims at developing and evaluating a method for testing the bed agglomeration tendency of a FB bed material by using a rotating furnace. A rotating furnace has been designed and tests have shown that three temperatures describing the increasing agglomeration tendency can be evaluated; TA when several particles stick to each other and to the crucible wall, TB when half of the material sticks to the wall and TC when almost all the material forms a ball in the crucible. Comparison with bed agglomeration tests has shown that TA is between 80 deg C to 130 deg C lower than the bed agglomeration temperature from fluid bed tests. It is shown that TB is closer to the bed agglomeration temperature and finally that the temperature TC is higher than the bed agglomeration temperature. It is concluded that in the rotating furnace sticking of particles is visualised early, and that this sticking will not cause defluidisation of the bed until more than half of the material in the crucible is sticky. Repeated tests has been performed at a heating rate of 5 deg/minute and a rotating speed of 12 rpm and a furnace inclination of 20 deg was found to give distinct results in the evaluation. The evaluation has shown to be reproducible at lower temperatures. At higher temperatures, around 1,000 deg C, the evaluation was complicated by a poor picture quality which probably can be improved by proper cooling of the camera. It has also been shown that sticking of material in the rotating furnace could be detected at relatively low temperatures of 750 deg C that disappeared at higher temperatures. This is likely to be explained by melting salts that evaporates as temperature increase. At even higher temperatures the sticking reappeared until a ball was formed in the crucible. The latter sticking is

  11. Disentangling the effects of polymer coatings on silver nanoparticle agglomeration, dissolution, and toxicity to determine mechanisms of nanotoxicity

    International Nuclear Information System (INIS)

    Silver nanoparticles (AgNPs) are frequently coated with a variety of polymers, which may affect various interdependent mechanisms of toxicity or antimicrobial action, including agglomeration and dissolution rates. Here, we systematically measure how citrate, dextran, 5 and 20 kDa poly(ethylene glycol) (PEG), and poly(vinyl pyrrolidone) coatings affect AgNP agglomeration, dissolution, and toxicity. In addition, to disentangle the coatings’ effects on agglomeration from their other effects, we produce multiple stable agglomerate sizes of several of the coated ∼23 nm AgNPs ranging from singly-dispersed to mean agglomerate sizes of several hundred nanometers. These dispersions allow us to independently study the effects of agglomeration and polymer coating on dissolution rate and hemolytic toxicity. We find that both hemolytic toxicity and dissolution rate are highest for the 5 kDa PEG coating, and toxicity and dissolution rate decrease significantly with increasing agglomerate size independent of coating. This correlation between toxicity and dissolution rate suggests that both polymer coating and agglomeration may affect hemolytic toxicity largely through their effects on dissolution. Because both the AgNP dissolution rate and hemolysis decrease only moderately compared to the large increases in agglomerate size, AgNPs’ hemolytic toxicity may be caused by their large surface area and consequently high dissolution rate, rather than from other size-specific effects. At the silver concentrations used in this work, silver dissolved from AgNPs is expected to be primarily in the form of AgCl NPs, which are therefore more likely than Ag+ ions to be the primary drivers of hemolytic toxicity. In addition, all AgNPs we tested are much more toxic to horse red blood cells than sheep red blood cells, highlighting the complexity of toxic responses and the need to test toxicity in multiple biological systems.

  12. Experimental determination of bed agglomeration tendencies of some common agricultural residues in fluidized bed combustion and gasification

    Energy Technology Data Exchange (ETDEWEB)

    Natarajan, E.; Rao, A.N. [Anna University, Madras (India). Centre for New and Renewable Sources of Energy; Ohman, M.; Nordin, A. [Umea University (Sweden). Energy Technology Centre; Gabra, M. [Lulea University of Technology (Sweden). Div. of Energy Engineering; Liliedahl, T. [Royal Institute of Technology, Stockholm (Sweden). Dept. of Chemical Engineering and Technology

    1998-12-31

    Ever increasing energy demand and the polluting nature of existing fossil fuel energy sources demonstrate the need for other non-polluting and renewable sources of energy. The agricultural residues available in abundance in many countries can be used for power generation. The fluidized bed technology seems to be suitable for converting a wide range of agricultural residues into energy, due to its inherent advantages of fuel flexibility, low operating temperature and isothermal operating condition. The major ash-related problem encountered in fluidized beds is agglomeration which, in the worst case, may result in total defluidization and unscheduled downtime. The initial agglomeration temperature for some common tropical agricultural residues were experimentally determined by using a newly developed method based on the controlled fluidized bed agglomeration test. The agricultural residues chosen for the study were rice husk, bagasse, cane trash and olive flesh. The results showed that the initial agglomeration temperatures were less than the initial deformation temperature predicted by the ASTM standard ash fusion tests for all fuels considered. The initial agglomeration temperatures of rice husk and bagasse were more than 1000{sup o}C. The agglomeration of cane trash and olive flesh was encountered at relatively low temperatures and their initial agglomeration temperatures in gasification were lower than those in combustion with both bed materials. The use of lime as bed material instead of quartz improved the agglomeration temperature of cane trash and olive flesh in combustion and decreased the same in gasification. The results indicate that rice husk and bagasse can be used in the fluidized bed for energy generation since their agglomeration temperatures are sufficiently high. (author)

  13. Investigation of coalescence kinetics of microcristalline cellulose in fluidised bed spray agglomeration: experimental studies and modelling approach

    Directory of Open Access Journals (Sweden)

    M. Peglow

    2005-06-01

    Full Text Available In this paper a model for fluidized bed spray agglomeration is presented. To describe the processes of heat and mass transfer, a physical based model is derived. The model takes evaporation process from the wetted particles as well as the effects of transfer phenomena between suspension gas and bypass gas into account. The change of particle size distribution during agglomeration, modeled by population balances, is linked to the heat and mass transfer model. A new technique is derived to extract agglomeration and nucleation rates from experimental data. Comparisons of experiments and simulations are presented.

  14. Study on urban agglomeration: Progress and prospects%城市群研究进展与展望

    Institute of Scientific and Technical Information of China (English)

    顾朝林

    2011-01-01

    Urban agglomeration is a complex with the central city as the core surrounded by two or more cities. It is the objective reflection of the economic growth and social development as well as industrial layout in a region. It has also become a main form of urbanization in developed countries. In fact, the "urban agglomeration" concept in China is the characteristics of a noun, no equivalence in foreign countries. In Western literature, the"urban agglomeration" means "urban cluster", that is, a big city and its surrounding satellite towns in remote sensing image formed the connected irregularities each other, and the spatial range includes "urbanization area (UA)" and "metropolitan area (MA)". Sometimes, some of metropolisesconnected each other are also called as urban agglomeration.United Nations gave a definition of urban agglomeration as follows: "Comprises a city or town proper and also the suburban fringe or thickly settled territory lying outside, but adjacent to, its boundaries. A single large urban agglomeration may comprise several cities or towns and their suburban fringes." Therefore, urban agglomeration in the Western concept includes the cities, towns and urban--region outlying areas. "Urban agglomeration" in China refers to geographical concepts of a group of major cities which are similar and interactions among administrative, transportation, economic, and social fields. In the 21st century, thanks to China's entry into the World Trade Organization, a national coastal urban agglomeration has become the main region for the national trade economy, export and the "world manufacturing bases". Urban agglomeration as an important urban spatial pattern was a unique choice to promote the process of urbanization in China. This article reviewed some progress in studies of urban agglomeration, such as the concept of urban agglomeration, overseas research of urban agglomeration, early researches of Chinese urban agglomeration and studies on Chinese urban

  15. XRD and DTA Analysis of Developed Agglomerated Fluxes for Submerged Arc Welding

    Directory of Open Access Journals (Sweden)

    Ajay Kumar

    2013-01-01

    Full Text Available A unique study of structural and chemical analysis of crystalline phases in developed agglomerated fluxes was carried out. Thirty-two fluxes were developed by using a mixture of oxides, halides, carbonates, silicates, and ferroalloys for submerged arc welding. The present paper focuses on only ten (out of thirty-two fluxes which were analyzed by X-ray diffraction (XRD to know the different types of oxides formed and changed in oxidation number of metallic centers after sintering process at around 850∘C. To know the effect of temperature over phase transformation and melting of different compounds, differential thermal analysis (DTA was carried out from 1000 to 1400∘C. This study aims to know the quantity of ions present (percentage and melting behavior of developed agglomerated fluxes for submerged arc welding process.

  16. An integrated modeling method for prediction of sulfur content in agglomerate

    Institute of Scientific and Technical Information of China (English)

    陈晓方; 桂卫华; 王雅琳; 吴敏

    2003-01-01

    Based on the idea of fusing modeling, an integrated prediction model for sintering process was proposed.A framework for sulfur content prediction was established, which integrated multi modeling ways together, including mathematical model combined with neural network(NN), rule model based on empirical knowledge and modelchoosing coordinator. Via metallurgic mechanism analysis and material balance computation, a mathematical model calculated the sulfur content in agglomerate by the material balance equation with some parameters predicted by NN method. In the other model, the relationship between sulfur content and key factors was described in the form of expert rules. The model-choosing coordinator based on fuzzy logic was introduced to decide the weight of result of each model according to process conditions. The model was tested by industrial application data and produced a relatively satisfactory prediction error. The model also preferably reflected the varying tendency of sulfur content in agglomerate as the evidence of its prediction performance.

  17. Analysis on Ecological Footprint of the Urban Agglomeration in Pearl River Delta

    Institute of Scientific and Technical Information of China (English)

    ZHONG; Yi; CHENG; Huan; BAI; Zhong-yan; PENG; Xiao-chun

    2012-01-01

    [Objective]The research aimed to calculate and analyze ecological footprint of the urban agglomeration in Pearl River Delta in 2009. [Method]9 cities in Pearl River Delta as research zone, by using calculation model of the ecological footprint, ecological footprint and security of the urban agglomeration in Pearl River Delta were calculated. Current situation and sustainable development condition of the ecological environment in Pearl River Delta were conducted quantitative analysis. [Result] Except construction land and woodland, other 4 kinds of lands were all in ecological deficit states in Pearl River Delta. Especially arable land and fossil fuel land had obvious ecological deficit. [Conclusion]Biological resource consumption level and energy consumption level in Pearl River Delta were higher. We ought to take a variety of measures to reduce ecological deficit, making development manner turn toward sustainable direction.

  18. Colloidal nanoparticles produced from Cu metal in water by laser ablation and their agglomeration

    Science.gov (United States)

    Im, Hee-Jung; Jung, Euo Chang

    2016-01-01

    Colloidal nanoparticles were prepared from Cu metal in water without any surfactant using a simple one-step laser ablation process with 532 nm Nd-YAG beam irradiation. A surface plasmon band of Cu nanoparticles near 580 nm was not observed; instead, oxidation of the Cu colloidal nanoparticles was noticed. This seems to be due to the partially oxidized copper oxides through the route Cu→Cu2O→CuO. Around 10-nm sized colloidal nanoparticles were agglomerated as a result of oxidation according to the time elapsed, and their sizes were increased to near 200 nm. The agglomeration was confirmed by not only images from transmission electron microscopy but also the long-term observation of the particle size distribution using photon correlation spectroscopy, laser-induced breakdown detection, and field flow fractionation.

  19. A Complex Network Approach for Nanoparticle Agglomeration Analysis in Nanoscale Images

    CERN Document Server

    Brandoli, Bruno; Orue, Jonathan; Arruda, Mauro; Goncalves, Diogo; Goncalves, Wesley; Moreira, Raphaell; Rodrigues-Jr, Jose

    2016-01-01

    Complex networks have been widely used in science and technology because of their ability to represent several systems. One of these systems is found in Biochemistry, in which the synthesis of new nanoparticles is a hot topic. However, the interpretation of experimental results in the search of new nanoparticles poses several challenges. This is due to the characteristics of nanoparticles images and due to their multiple intricate properties; one property of recurrent interest is the agglomeration of particles. Addressing this issue, this paper introduces an approach that uses complex networks to detect and describe nanoparticle agglomerates so to foster easier and more insightful analyses. In this approach, each detected particle in an image corresponds to a vertice and the distances between the particles define a criterion for creating edges. Edges are created if the distance is smaller than a radius of interest. Once this network is set, we calculate several discrete measures able to reveal the most outsta...

  20. How coupling agent ordering on the surface of zirconia nanocrystals influences their agglomeration

    International Nuclear Information System (INIS)

    Full text: The ordering of dodecyl chains has been investigated in mixed monolayers of phosphonic acid capping agents on the surface of hydrothermal prepared zirconia nanocrystals. As co-capping agent for the mixed monolayer formation, methyl-, phenyl-, pyryl- and tert-butyl phosphonic acid have been used to investigate series with different mixing ratios. In this study, the influence of the various molecules on the alkyl chain disordering is discussed. Small angle X-ray scattering (SAXS) studies show that with increasing amount of co-capping agent the agglomeration of the particles decreases. This behavior correlates with the ordering of the surface bond alkyl chains investigated by Fourier transform infrared spectroscopy (FTIR). It can be concluded that interparticle bilayers, formed via long alkyl chain packing, are responsible for the formation of dense particle agglomerates and can be controlled on a molecular level by co-adsorbing various molecules. (author)

  1. Agglomeration Economies and Global Cities: The case of London, New York and relativity

    OpenAIRE

    Michael, L.

    2015-01-01

    This paper evaluates the manner in which agglomeration influenced formation of cities and how this has changed with the evolution of ‘global cities’. Furthermore, a study of global cities concentrating on London and New York, investigating the sales turnover of commercial real estate, is undertaken to investigate any changes in relativity. Changes in capital flows recorded in commercial real estate transactions over time will be analysed using market data supplied by RCA for each city sector ...

  2. Do large agglomerations lead to economic growth? evidence from urban India

    OpenAIRE

    Tripathi, Sabyasachi

    2012-01-01

    The cities and towns of India constitute the world’s second largest urban system besides contributing over 50 per cent of the country’s Gross Domestic Product (GDP). This phenomenon has been neglected by the existing studies and writings on urban India. By considering 59 large cities in India and employing new economic geography models, this paper investigates the relevant state and city-specific determinants of urban agglomeration. In addition, the spatial interactions between cities and the...

  3. Quantum dot agglomerates in biological media and their characterization by asymmetrical flow field-flow fractionation.

    Science.gov (United States)

    Moquin, Alexandre; Neibert, Kevin D; Maysinger, Dusica; Winnik, Françoise M

    2015-01-01

    The molecular composition of the biological environment of nanoparticles influences their physical properties and changes their pristine physicochemical identity. In order to understand, or predict, the interactions of cells with specific nanoparticles, it is critical to know their size, shape, and agglomeration state not only in their nascent state but also in biological media. Here, we use asymmetrical flow field-flow fractionation (AF4) with on-line multiangle light scattering (MALS), dynamic light scattering (DLS) and UV-Visible absorption detections to determine the relative concentration of isolated nanoparticles and agglomerates in the case of three types of semi-conductor quantum dots (QDs) dispersed in Dulbecco's Modified Eagle Media (DMEM) containing 10% of fetal bovine serum (DMEM-FBS). AF4 analysis also yielded the size and size distribution of the agglomerates as a function of the time of QDs incubation in DMEM-FBS. The preferred modes of internalization of the QDs are assessed for three cell-types, N9 microglia, human hepatocellular carcinoma cells (HepG2) and human embryonic kidney cells (Hek293), by confocal fluorescence imaging of live cells, quantitative determination of the intracellular QD concentration, and flow cytometry. There is an excellent correlation between the agglomeration status of the three types of QDs in DMEM-FBS determined by AF4 analysis and their preferred mode of uptake by the three cell lines, which suggests that AF4 yields an accurate description of the nanoparticles as they encounter cells and advocates its use as a means to characterize particles under evaluation. PMID:25542679

  4. Agglomeration and filtration of colloidal suspensions with DVLO interactions in simulation and experiment

    OpenAIRE

    2009-01-01

    Cake filtration is a widely used solid-liquid separation process. However, the high flow resistance of the nanoporous filter cake lowers the efficiency of the process significantly. The structure and thus the permeability of the filter cakes depend on the compressive load acting on the particles, the particles size, and the agglomeration of the particles. The latter is determined by the particle charge and the ionic strength of the suspension, as described by the Derjaguin-Landau-Verwey-Overb...

  5. Agglomeration Effects and Japanese Food Industry Investment in China: Evidence from the Cities

    OpenAIRE

    Jin, Shaosheng; TOKUNAGA Suminori; AKUNE Yuko; KAGEYAMA Masahiro

    2006-01-01

    This paper uses the data from Chugoku Shinshutsu Kigyou Ichiran 2003-2004 (A View of Japanese Enterprises Investments in China 2003-2004) to study 1ocation choice of Japanese food industry investment in 231 Chinese cities from 1992 to 2001, paying a particular attention to agglomeration effects. A negative binominal model indicates that labor cost (WAGE) is the most important factor that deters Japanese food industry investment. Market size (GDP), raw material (MATER), port (PORT) and policy ...

  6. Agglomeration Economies and Industry Location Decisions: The Impacts of Vertical and Horizontal Spillovers

    OpenAIRE

    Cohen, Jeffrey P.; Morrison Paul, Catherine J.

    2001-01-01

    Economic analysis of production processes and performanace typically neglects consideration of spatial and industry inter-dependencies that may affect economic performance, although there is increasing theoretical recognition that such linkages may be both substantive and expanding. In particular, thick market or agglomeration effects may arise due to knowledge or other types of spillovers associated with own-industry (horizontal), and supply-side or demand-driven(vertical), externalities. ...

  7. Agglomeration Economies and Industry Location Decisions: The Impacts of Vertical and Horizontal Spillovers

    OpenAIRE

    Cohen, Jeffrey P.; Morrison Paul, Catherine J.

    2001-01-01

    Economic analysis of production processes and performance typically neglects consideration of spatial and industry inter-dependencies that may affect economic performance, although there is increasing theoretical recognition that such linkages may be both substantive and expanding. In particular, thick market or agglomeration effects may arise due to knowledge or other types of spillovers associated with own-industry (horizontal), and supply-side or demand-driven (vertical), externalities. In...

  8. Implications of Agglomeration Economics and Market Access for Firm Growth in Food Manufacturing

    OpenAIRE

    Schmit, Todd M.; Hall, Jeffrey S.

    2011-01-01

    With the persistant changes in technology and increased competition in food manufacturing, it is important to reassess the effects of agglomeration economies and market access on the performance of firms in the industry. Using survey data from a recent survey of New York state food processors, an ordered logit analysis reveals that firm growth is related to important upstream and downstream market conditions as reflected in increased access to agricultural inputs and growing population canter...

  9. Spherical agglomerates of pure drug nanoparticles for improved pulmonary delivery in dry powder inhalers

    International Nuclear Information System (INIS)

    The aim of this study was to produce micron-sized spherical agglomerates of pure drug nanoparticles to achieve improved aerosol performance in dry powder inhalers (DPIs). Sodium cromoglicate was chosen as the model drug. Pure drug nanoparticles were prepared through a bottom-up particle formation process, liquid antisolvent precipitation, and then rapidly agglomerated into porous spherical microparticles by immediate (on-line) spray drying. Nonporous spherical drug microparticles with similar geometric size distribution were prepared by conventional spray drying of the aqueous drug solution, which together with the mechanically micronized drug particles were used as the control samples. The three samples were characterized by field emission scanning electron microscopy, laser diffraction, Brunauer–Emmett–Teller analysis, density measurement, powder X-ray diffraction, and in vitro aerosol deposition measurement with a multistage liquid impinger. It was found that drug nanoparticles with a diameter of ∼100 nm were precipitated and agglomerated into highly porous spherical microparticles with a volume median diameter (D50%) of 2.25 ± 0.08 μm and a specific surface area of 158.63 ± 3.27 m2/g. In vitro aerosol deposition studies showed the fine particle fraction of such spherical agglomerates of drug nanoparticles was increased by more than 50 % in comparison with the control samples, demonstrating significant improvements in aerosol performance. The results of this study indicated the potential of the combined particle engineering process of liquid antisolvent precipitation followed by immediate (on-line) spray drying in the development of novel DPI drug products with improved aerosol performance.

  10. Utility assessment of human development indicators: Case of Kolkata Urban agglomeration

    OpenAIRE

    Keya Chakraborty; Joy Sen

    2011-01-01

    The present paper attempts to establish a set of variables to find out the extent and levels of inequality in Human Development Indicators (HDIs) driven development based on a geographic delineation of Kolkata Urban Agglomeration (KUA). The study is based on the geographic delineation of the region of KUA. Given this background, it assesses health, education and economic scenario of the study area by variables of rates of mortality, literacy and working population, respectively. For the purpo...

  11. Radioisotope studies on the paradox in dispersion and agglomeration of sewage greases discharged from ocean outfalls

    International Nuclear Information System (INIS)

    Experiments have been undertaken in the ocean off Sydney, Australia to monitor the movement and the dispersion of sewage solids. These solids were labelled with a radioisotope, gold-198 prior to ocean discharge. The labelled material was followed at sea using submersible scintillation detectors. Lateral and vertical dispersion coefficients were determined. The experiments showed that under some conditions the labelled sewage grease dispersed and under others the grease agglomerated. This variation is explained in terms of non-conservative processes

  12. Percolation threshold and electrical conductivity of graphene-based nanocomposites with filler agglomeration and interfacial tunneling

    Science.gov (United States)

    Wang, Yang; Shan, Jerry W.; Weng, George J.

    2015-08-01

    The dispersion state or degree of agglomeration of graphene is known to have a significant influence on the percolation threshold and electrical conductivity of graphene-based polymer nanocomposites. In addition, an imperfectly conducting interface and tunneling-assisted interfacial conductivity can also affect the overall conductivity. In this paper, a continuum theory is developed that considers all these factors. We first present a two-scale composite model consisting of graphene-rich regions serving as the agglomerates and a graphene-poor region as the matrix. We then introduce the effective-medium theory to determine the percolation threshold and electrical conductivity of the agglomerate and the composite. To account for the effect of imperfect interfaces, a thin layer of interphase with low conductivity is introduced to build a thinly coated graphene, while to account for the contribution of electron hopping from one graphene to another, Cauchy's statistical function which can reflect the increased tunneling activity near the percolation threshold is introduced. It is shown that the percolation threshold of the nanocomposite is controlled by two dispersion parameters, a and b, and the aspect ratio of agglomerates, αR . It is also shown that the overall conductivity of the nanocomposite mainly depends on the intrinsic conductivity of graphene and polymer matrix, the intrinsic interfacial resistivity, and the tunneling-assisted hopping process. We highlight the conceived theory by demonstrating that a set of recently measured data on the percolation threshold and electrical conductivity of graphene/polystyrene nanocomposites can be well captured by it.

  13. Different roles of municipalities in a urban agglomeration: a regional agent-based economic model

    OpenAIRE

    Baruffini, Moreno; Mini, Valentina; Stricker, Luzius

    2015-01-01

    Historically Switzerland is characterized by numerous small towns. During the twentieth century, the image of Swiss cities has changed: the expansion of the city has reached the limits of administrative urban borders, penetrating in peripheral locations. The main reasons concern not only the territorial environment, but also the possibility to support public services and public investments. Currently, urban agglomerations include dozens of municipalities and this is seen as a virtuous strateg...

  14. The role of specialisation and diversity externalities in the agglomeration of innovative activities

    OpenAIRE

    Paci, Raffaele; Usai, Stefano

    1999-01-01

    This paper contributes to the analysis of the process of spatial agglomeration of innovative activities by investigating directly its determinants. Our main purpose is to identify the extent to which the degree of industrial specialisation (Marshall externalities) or diversity (Jacobs externalities) in the region may affect the innovative output in a particular local industry. Moreover, we test if any relevant difference arises with respect to the role of diversity in metropolitan areas and i...

  15. The Determinants of Regional Specialisation in Business Services: Agglomeration Economies, Vertical Linkages and Innovation

    OpenAIRE

    MELICIANI Valentina; Savona, Maria

    2011-01-01

    The article accounts for the determinants of sectoral specialisation in business services (BS) across the EU-27 regions as determined by: (i) agglomeration economies (ii) the region-specific structure of intermediate linkages (iii) technological innovation and knowledge intensity and (iv) the presence of these factors in neighbouring regions. The empirical analysis draws upon the REGIO panel database over the period 1999–2003. By estimating a Spatial Durbin Model, we find significant spatial ...

  16. Housing Market and Agglomeration of Rent-Seeking Activities: Implications for Regional Development

    OpenAIRE

    Peng, Shin-Kun

    2014-01-01

    Rent-seeking is defined as exercising privileges or expending resources in order to obtain uncompensated gain by redistributing the wealth of others without reciprocating any benefits back to society through wealth creation. This paper pioneers in analyzing the agglomeration of rent-seeking activities in geography and the corresponding impact on regional economies. First of all, we construct a theoretical model based on the standard settings in the literature of economic geography with two ty...

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

    International Nuclear Information System (INIS)

    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 SO2 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)

  18. Entrepreneurial Clusters and the Co-agglomeration of Related Industries: Spinouts in Portuguese Plastics and Molds

    OpenAIRE

    Baptista, Rui; Costa, Carla

    2014-01-01

    The success of ?entrepreneurial clusters' has led policymakers towards extensive efforts to seed local entrepreneurship. A particularly important determinant of the ?supply of entrepreneurs' are industry linkages within cities or regions. Indeed, studies consistently find that the most powerful predictor of future entrepreneurship for a city or region is the presence and strength of incumbent firms in the same or in related industries. This study examines how co-agglomeration (or collocation)...

  19. Bed agglomeration in biomass fueled CFB-boilers; Sintring av baeddmaterial vid biobraensleeldning i CFB

    Energy Technology Data Exchange (ETDEWEB)

    Zintl, F. [TPS Termiska Processer AB, Nykoeping (Sweden)

    1997-02-01

    In fluidized-bed boilers fired with solid fuels operational problems caused by spontaneous defluidization are sometimes observed. This bed agglomeration can be caused by sintering phenomena where fuel components and/or bed material may be involved. In serious cases the problems can lead to expensive operation breaks. The objective in this project was to show whether this type of operational problems can be minimized by choice of other than conventional bed materials. The study was carried out as model experiments in a larger laboratory scale. In a fluidized bed fired with propane a number of both well known and more unusual bed materials were tried out. The choice of bed materials included some common sands (silver and quartz sand) and, as possible alternatives, olivine sand, zirconium sand, calcined dolomite and the synthetic materials sintered magnesite (MgO) and mullite (alumina silicate). The model experiments were started at about 700 deg C and the temperature then raised until an irreversible bed agglomeration was observed, or to a maximum of 1100 deg C. The most promising results were obtained with calcined dolomite, being an active bed material. With this material no irreversible agglomerations were observed at all. The expensive synthetic materials sintered magnesite and mullite and the zirconium sand turned out as the next best. Olivine sand, on the other hand, showed a clear sensitivity to physical agglomeration and some sensitivity also towards sintering. The common sand types based on silicon oxide clearly showed the worst results. 12 refs, 5 figs, 1 tab 12 refs, 5 figs, 1 tab

  20. A Free, Open-Source Tool for Identifying Urban Agglomerations Using Point Data

    OpenAIRE

    Day, Jennifer; Chen, Yiqun; Ellis, Peter; Roberts, Mark

    2015-01-01

    This paper describes a software tool for identifying urban agglomerations in low-information settings. The framework outlined in this paper is designed to work using point data. Our tool and all required data are provided free and in open-source format. This paper describes the advantages and disadvantages of using point-based geographies in regional analysis, discusses the practical and ethical challenges of distinguishing urban from rural regions, details the function of our software, and d...

  1. Urban Amenities or Agglomeration Economies? Locational Behaviour and Entrepreneurial Success of Dutch Fashion Designers

    OpenAIRE

    Rik Wenting; Oedzge Atzema; Koen Frenken

    2008-01-01

    Urban economic growth and industrial clustering is traditionally explained by Marshallian agglomeration economies benefiting co-located firms. The focus on firms rather than people has been challenged by Florida arguing that urban amenities and a tolerant climate attract creative people, and the firms they work for, to certain cities. We analyse to what extent these two mechanisms affect the locational behaviour of Dutch fashion designers. On the basis of a questionnaire, we find that urban a...

  2. Prediction of powder stickiness along spray drying process in relation to agglomeration

    OpenAIRE

    Gianfrancesco, Alessandro; Turchiuli, Christelle; Dumoulin, Élisabeth; Palzer, S.

    2009-01-01

    The spray drying process consists of a fast convective drying of liquid droplets by hot air. Initially, the water activity (aw) of a drop is close to 1. During drying, the drop surface aw decreases while viscosity increases until reaching a sticky rubbery state before further drying. This can be observed for products such as carbohydrates, leading to particles sticking on walls (product losses) or to adhesion between particles leading to agglomeration. In this study, particle stickiness was i...

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

    Science.gov (United States)

    Zhao, Yun; Zeng, Xinwu; Tian, Zhangfu

    2015-10-01

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

  4. Study on China’s Electronic Information Industrial Agglomeration and Regional Industrial Competitiveness

    OpenAIRE

    Xuan Zhaohui; Wu Aizhi; Lv Yongbo

    2013-01-01

    Spatial agglomeration and industrial competitiveness are currently two key issues in the study of China’s electronic information industrial development. Based on the data for 1995 - 2010, this paper establishes the indicator system to evaluate the competitiveness of regional electronic information industry. In this paper, location Gini coefficient and the indicator of concentration rate are applied to analyze the characteristics and historical evolution of China’s electronic information indus...

  5. Local Agglomeration, Entrepreneurship and the Great Recession: Evidence from Italian Industrial Districts

    OpenAIRE

    Brunello, Giorgio; Langella, Monica

    2014-01-01

    We ask whether local agglomeration affects how recessions impact on entrepreneurship by comparing the probability of being an entrepreneur before and after the Great 2008 Recession in local labour markets where industrial districts are present and in comparable areas. Using Italian Labour Force quarterly data from 2006 to 2011 and a "difference-in-differences" approach, we find that for males aged 40 to 55, who are more likely to be entrepreneurs, the negative effect of the recession on entre...

  6. Estimating Urban Agglomeration Economies for India: A New Economic Geography Perspective

    OpenAIRE

    Tripathi, Sabyasachi

    2012-01-01

    The main objective of this paper is to provide answer to an important question: Are Indian firms or industries in urban areas operating under decreasing returns to scale or increasing returns to scale? Scale economies are one of the main assumptions of new economic geography models that posit the formation of agglomeration economies. For this purpose, we use Kanemoto et al. (1996) model for estimation of aggregate production function and to derive the magnitude of scale economies. Using firm ...

  7. Location choice of German multinationals in the Czech Republic : the importance of agglomeration economies

    OpenAIRE

    Hecht, Veronika

    2015-01-01

    This paper analyses the location choice of German investors in the Czech Republic based on a unique dataset covering all Czech companies with a German equity holder in 2010. The identification of the regional determinants of foreign direct investment (FDI) location is an important regional policy issue as FDI is supposed to improve the labour market conditions of the host region. Using a nested logit approach the impact of agglomeration economies, labour market conditions and distance on the ...

  8. Phagocytosis-dependent and independent mechanisms underlie the microglial cell damage caused by carbon nanotube agglomerates.

    Science.gov (United States)

    Shigemoto-Mogami, Yukari; Hoshikawa, Kazue; Hirose, Akihiko; Sato, Kaoru

    2016-01-01

    Although carbon nanotubes (CNTs) are used in many fields, including energy, healthcare, environmental technology, materials, and electronics, the adverse effects of CNTs in the brain are poorly understood. In this study, we investigated the effects of CNTs on cultured microglia, as microglia are the first responders to foreign materials. We compared the effects of sonicated suspensions of 5 kinds of CNTs and their flow-through filtered with a 0.22 µm membrane filter on microglial viability. We found that sonicated suspensions caused microglial cell damage, but their flow-through did not. The number of microglial aggregates was well correlated with the extent of the damage. We also determined that the CNT agglomerates consisted of two groups: one was phagocytosed by microglia and caused microglial cell damage, and the other caused cell damage without phagocytosis. These results suggest that phagocytosis-dependent and independent mechanisms underlie the microglial cell damage caused by CNT agglomerates and it is important to conduct studies about the relationships between physical properties of nanomaterial-agglomerates and cell damage. PMID:27432236

  9. A sensitivity of aerosol agglomeration and deposition using the MAEROS model

    International Nuclear Information System (INIS)

    In support of the MELCOR program, a study of the sensitivities and uncertainties associated with MAEROS aerosol code predictions has been performed for TMLB accident conditions using Latin hypercube sampling techniques and regression analysis methods. Agglomeration and deposition in the reactor containment of two aerosol components, and in-vessel aerosol and an ex-vessel aerosol, were examined by varying the values of 24 code input parameters that defined containment geometry, containment thermal-hydraulic conditions, aerosol source characteristics, and agglomeration and deposition rate constants. Twenty aerosol size sections, spanning the size range of 0.01 to 200 μ were used to develop the sensitivities and uncertainties associated with code predictions of the total suspended mass, the time to 90 percent deposition, and the total integrated gas borne mass density of each aerosol component. These sensitivities and uncertainties were found to depend principally on the following four input parameters: the source strength of the ex-vessel aerosol, the agglomeration shape factor, the turbulent energy dissipation rate, and the particle mass density

  10. Sensitivity study of aerosol agglomeration and deposition using the MAEROS model

    International Nuclear Information System (INIS)

    In support of the MELCOR program, a study of the sensitivities and uncertainties associated with MAEROS aerosol code predictions has been performed for TMLB accident conditions using Latin hypercube sampling techniques and regression analysis methods. Agglomeration and deposition in the reactor containment of two aerosol components, an in-vessel aerosol and an ex-vessel aerosol, were examined by varying the values of 24 code input parameters that defined containment geometry, containment thermal-hydraulic conditions, aerosol source characteristics, and agglomeration and deposition rate constants. Twenty aerosol size sections, spanning the size range 0.01 to 200μ, were used to develop the sensitivities and uncertainties associated with code predictions of the total suspended mass, the time to 90% deposition, and the total integrated gas borne mass density of each aerosol component. These sensitivities and uncertainties were found to depend principally on the following four input parameters: the source strength of the ex-vessel aerosol, the agglomeration shape factor, the turbulent energy dissipation rate, and the particle mass density. Decreasing the number of aerosol size sections to 15 or 10 sections did not significantly alter any calculated result; and use of only 5 sections altered results by less than 10%. Results were also unaffected by increasing the lower bound of the aerosol size distribution from 0.01 to 0.1μ or decreasing the upper bound from 200 to 50μ

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

    Directory of Open Access Journals (Sweden)

    Parameswara Rao Vuddanda

    2014-01-01

    Full Text Available 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.

  12. Experimental and numerical study on the optical properties and agglomeration of nanoparticle suspensions

    International Nuclear Information System (INIS)

    Nanoparticles have garnered significant interest because of their ability to enhance greatly the optical properties of the base fluid in which they are suspended. The optical properties of nanoparticles are sensitive to the materials used, as well as to the host medium. Most fluids exhibit refractive indices that are highly temperature-dependent, resulting in nanoparticle suspensions which also exhibit temperature-dependent optical properties. Previous work has shown that temperature increases result in decreased absorption in nanoparticle suspensions. Here, we expand previous work to include core–shell particles due to the potential spectral shifts in optical properties that will arise from the base fluid with temperature changes and the role of agglomeration under temperature cycling through both experimental and numerical efforts. Thermal cycling tests for silica and gold, the constituents of the core–shell nanoparticles used in this study, were tested to determine the extent of particle agglomeration resulting from up to 200 accelerated heating cycles. Optical properties were recorded after heating two base fluids (water and ethylene glycol) with multiple surfactants for silver nanospheres and silica–gold core–shell nanoparticles. It was found that the temperature results in a small increase in the transmittance for both particle types and a blue shift in the spectral transmittance for core–shell nanoparticles. Further, the coupling effect of temperature and agglomeration played a significant role in determining both the spectral properties—particularly the resulting transmittance—of the silver nanoparticle suspensions

  13. Agglomeration of urinary nanocrystallites: Key factor to formation of urinary stones

    International Nuclear Information System (INIS)

    With transmission electron microscopy (TEM) and nanoparticle size analyzer, comparative studies were conducted on the property variation of nanocrystallites in the urine of 5 lithogenic patients and 5 healthy subjects following the placement time (t1). These properties include average particle size (d), size distribution, intensity-autocorrelation function, Zeta potential (ζ) and aggregation state. With the prolongation of t1 from 0 h to 4 h, d value of the nanocrystallites in urine of lithogenic patients increased from 742 nm to 1667 nm, the autocorrelation time increased from 7.68 ms to 1050 ms and ζ decreased from -1.52 mV to -4.44 mV, respectively; the autocorrelation curves were of fluctuating and unsmooth, and TEM showed that most of the patient's urinary nanocrystallites were in aggregation state and three types of agglomeration were observed. However, for nanocrystallites in urine of healthy subjects, there was little variation in the above properties within 4 h. The autocorrelation curves were of regular and smooth, and TEM showed that healthy urinary nanocrystallites were well-dispersed. The above results show that the nanocrystallites in urine of healthy subjects can keep stability, whereas those of lithogenic patients are easier to agglomerate gradually; and the agglomeration of urinary nanocrystallites is the key factor to stone formation.

  14. Assessment of Morphological and Functional Changes in Organs of Rats after Intramuscular Introduction of Iron Nanoparticles and Their Agglomerates

    OpenAIRE

    2015-01-01

    The research was performed on male Wistar rats based on assumptions that new microelement preparations containing metal nanoparticles and their agglomerates had potential. Morphological and functional changes in tissues in the injection site and dynamics of chemical element metabolism (25 indicators) in body were assessed after repeated intramuscular injections (total, 7) with preparation containing agglomerate of iron nanoparticles. As a result, iron depot was formed in myosymplasts of injec...

  15. An Empirical Analysis of Agglomeration Effect in the Japanese Food Industry -Panel Analysis Using Flexible Translog Production Function-

    OpenAIRE

    KAGEYAMA Masahiro; TOKUNAGA Suminori; AKUNE Yuko

    2006-01-01

    In this paper, we examine the existence of agglomeration effect on production in the Japanese food industry from 1985 to 2000 using plant-level 4-digit subclassification, panel dataset and new agglomeration index in Akune and Tokunaga (2005), and Tokunaga, Kageyama, and Akune (2005), based on Ellison and Glaeser (1997). This is an improvement on the the conventional indices such as Location Quotient (LQ) or Location Gini Coefficient (L).When we apply a flexible translog production function an...

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

    OpenAIRE

    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

    2014-01-01

    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 ...

  17. Study on GIS Visualization in Evaluation of the Human Living Environment in Shenyang-Dalian Urban Agglomeration

    OpenAIRE

    Hou, Kang; Zhou, Jieting; Li, Xuxiang; Ge, Shengbin

    2016-01-01

    Analysis of human living environmental quality of Shenyang-Dalian urban agglomerations has important theoretical and practical significance in rapid development region. A lot of investigations have been carried for Shenyang-Dalian urban agglomerations, including 38 counties. Based on the carrying capacity of resources, natural and socioeconomic environmental factors and regional changes of human living environmental evaluation are analyzed with the application of geographic information system...

  18. Comparative study of chemical cold agglomeration between two Brazilian phosphate fines: Patos de Minas and Catalao-Go, Brazil

    International Nuclear Information System (INIS)

    The viability for using the phosphoric acid as chemical binder for agglomeration of phosphate fines from Catalao, Brazil, based on the good results obtained for pelletizing phosphate fines from Patos de Minas, is studied. The granulometric and chemical characterizations by fluorescence spectrometry and X-ray diffraction were done. The results presented different physical and chemical properties, even thus the phosphoric acid could be used with advantages for chemical agglomeration of phosphate fines from Catalao. (author)

  19. Why did Spanish regions not converge before the Civil War? Agglomeration and (regional) growth revisited: Spain, 1870-1930

    OpenAIRE

    Alfonso Díez-Minguela; Julio Martínez-Galarraga; Daniel A. Tirado Fabregat

    2013-01-01

    In this paper we explore the relationship between the spatial agglomeration of economic activity and regional economic growth in Spain during the period 1870-1930. The study allows us to revisit the existence of a trade-off between economic growth and territorial cohesion and also to examine whether the agglomeration of production was a key element to explain the upswing in regional income inequality in Spain during the country’s early stages of development. In doing this, we present alternat...

  20. The Effect of Urban Heat Island on Climate Warming in the Yangtze River Delta Urban Agglomeration in China

    OpenAIRE

    Qunfang Huang; Yuqi Lu

    2015-01-01

    The Yangtze River Delta (YRD) has experienced rapid urbanization and dramatic economic development since 1978 and the Yangtze River Delta urban agglomeration (YRDUA) has been one of the three largest urban agglomerations in China. We present evidence of a significant urban heat island (UHI) effect on climate warming based on an analysis of the impacts of the urbanization rate, urban population, and land use changes on the warming rate of the daily average, minimal (nighttime) and maximal (day...

  1. Determinants of environmental domain of quality of life in economically active population living in Silesian agglomeration, Poland

    OpenAIRE

    Małgorzata Kowalska; Felix Danso; Maria Humeniuk; Elżbieta Kułak; Hubert Arasiewicz

    2013-01-01

    Objectives: The aim of this paper is to identify the factors that determine the environmental domain of quality of life in economically active adults living in the industrial agglomeration in Poland. Materials and Methods: During the crosssectional epidemiological study conducted among the economically active population aged 45–60, we used a short version of the WHOQOL-BREF questionnaire. Respondents were recruited randomly from selected factories located in the Silesian Agglomeration. The st...

  2. Quantitative characterization of agglomerates and aggregates of pyrogenic and precipitated amorphous silica nanomaterials by transmission electron microscopy

    OpenAIRE

    De Temmerman Pieter-Jan; Van Doren Elke; Verleysen Eveline; Van der Stede Yves; Francisco Michel Abi; Mast Jan

    2012-01-01

    Abstract Background The interaction of a nanomaterial (NM) with a biological system depends not only on the size of its primary particles but also on the size, shape and surface topology of its aggregates and agglomerates. A method based on transmission electron microscopy (TEM), to visualize the NM and on image analysis, to measure detected features quantitatively, was assessed for its capacity to characterize the aggregates and agglomerates of precipitated and pyrogenic synthetic amorphous ...

  3. A proposed agglomerate model for oxygen reduction in the catalyst layer of proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Highlights: • We developed a new agglomerate model to describe oxygen reduction reaction. • We showed how to calculate the model parameters from catalyst layer structure. • We verified the agglomerate model. - Abstract: Oxygen diffusion and reduction in the catalyst layer of PEM fuel cell is an important process in fuel cell modelling, but models able to link the reduction rate to catalyst-layer structure are lack; this paper makes such an effort. We first link the average reduction rate over the agglomerate within a catalyst layer to a probability that an oxygen molecule, which is initially on the agglomerate surface, will enter and remain in the agglomerate at any time in the absence of any electrochemical reaction. We then propose a method to directly calculate distribution function of this probability and apply it to two catalyst layers with contrasting structures. A formula is proposed to describe these calculated distribution functions, from which the agglomerate model is derived. The model has two parameters and both can be independently calculated from catalyst layer structures. We verify the model by first showing that it is an improvement and able to reproduce what the spherical model describes, and then testing it against the average oxygen reductions directly calculated from pore-scale simulations of oxygen diffusion and reaction in the two catalyst layers. The proposed model is simple, but significant as it links the average oxygen reduction to catalyst layer structures, and its two parameters can be directly calculated rather than by calibration

  4. Modern understanding of ‘geoeconomic position’ and the Saint Petersburg agglomeration

    Directory of Open Access Journals (Sweden)

    Kuznetsov S. V.

    2014-05-01

    Full Text Available This article presents a modern interpretation of the concept of ‘geoeconomic situation’ as applied to one of the most important centers of the Baltic region — the St. Petersburg agglomeration. The coastal location of the agglomeration and close connections with the Leningrad region make it possible to consider the Saint Petersburg coastal region (Baltic Area as a whole. The article sets out not only to verify, confirm, and explain the features of the geoeconomic position of the coastal region, but also to describe the contiguous geoeconomic space. The position of the St. Petersburg coastal region is of crucial importance for ensuring a steady growth of regional economy, the propagation of industrialization impulses, and modernization in the heart of Russian Northwestern macroregion. At the same time, the specific features of the region’s geoeconomic position magnify the ‘inherited’ ad acquired effects of focal industrialization and space polarization, which creates additional prerequisites for the inversion of the Russian economic space — ‘Russia of the physical space’ and ‘the economic space of Russia’. The study uses traditional methodology of economic geography (the territorial, cluster, and spatial approaches and the geoeconomic approach developed by the authors. The article also addresses recent findings in regional economy and spatial studies. It is aimed at the development of the geoeconomic paradigm in the framework of social geography and that of spatial science. An analysis of the geoeconomic position and the developing spatial relations can be of interest for researchers of geographic clusters, agglomerations, and such cross-border forms of cooperation, as growth triangles, for example.

  5. Dust Explosion Characteristics of Agglomerated 35 nm and 100 nm Aluminum Particles

    Directory of Open Access Journals (Sweden)

    Hong-Chun Wu

    2010-01-01

    Full Text Available In the experiment, nanoparticles of 35 nm Al and 100 nm Al powders, respectively, formed particles with average sizes of 161 nm and 167 nm in agglomeration. The characteristics of dust cloud explosions with the two powder sizes, 35 nm and 100 nm, revealed considerable differences, as shown here: (dp/dtmax-35 nm = 1254 bar/s, (dp/dtmax-100 nm = 1105 bar/s; Pmax-35 nm = 7.5 bar, Pmax-100 nm = 12.3 bar, and MEC-35 nm = 40 g/m3, MEC-100 nm = 50 g/m3. The reason of Pmax-35 nm value is smaller than Pmax-100 nm may be due to agglomeration. From an analysis of the explosive residue, the study found that nanoparticles of 35 nm Al powder became filamentous strands after an explosion, where most of 100 nm Al nanoparticles maintained a spherical structure, This may be because the initial melting temperature of 35 nm Al is 435.71°C, while that for 100 nm Al is 523.58°C, higher by 87.87°C. This study discovered that explosive property between the 35 nm Al and 100 nm Al powders after agglomeration were different.

  6. A Novel Plasma-Sprayed Nanostructured Coating with Agglomerated-Unsintered Feedstock

    Science.gov (United States)

    Gao, Yang; Zhao, Yan; Yang, Deming; Gao, Jianyi

    2016-01-01

    In this article, an unusual agglomerated powder of Y2O3-stabilized ZrO2 (YSZ) that did not undergo calcination was introduced as a feedstock for thermal spray deposition using internal injection atmospheric plasma spray (APS) and the very-low-pressure plasma spray (VLPPS) methods at an ambient pressure of 100-150 Pa. The results show that the microstructure of the coating is influenced not only by the spray parameters (such as arc gas composition, ambient pressure, and arc current) but also by the manufacture process of the agglomerates particularly the sintering process. The microstructure of the coating exhibited a bimodal structure if the APS method was used; in this case, the microstructure resembles that of other nanostructured coatings using regular agglomerated-sintered feedstock. A coating having a novel fully nano-equiaxed structure with a microporosity of 10-15% was first successfully deposited using VLPPS with 20Ar-30He SLPM plasma gas flows at a current of 500 A. The experimental results suggest that the nano-scale equiaxed structure in the coating is directly formed from original nanoparticles that had undergone melting, while inside the nozzle they were subsequently solidified on the substrate. The VLPPS method, which offers some unique advantages over the conventional plasma spray process, is generic in nature and can potentially be used to deposit a wide variety of ceramic coatings for diverse applications. The thermal conductivity values of the fully nanostructured and bimodal structured coatings were measured, and the microstructures of the coating both in the as-sprayed state and after heat treatment for 10 h at 1300 °C were investigated.

  7. Consumption of milk and milk products in the population of the Upper Silesian agglomeration inhabitants

    OpenAIRE

    Kardas, Marek; Grochowska-Niedworok, Elżbieta; Kolasa, Ilona; Grajek, Mateusz; Bielaszka, Agnieszka; Kiciak, Agata; Muc-Wierzgoń, Małgorzata; Całyniuk, Beata

    2016-01-01

    Background: Providing the appropriate amount of nutrients at every stage of life is a key element determining the proper development and functioning of the body.Objective: Because of the nutritional value and resulting position of milk and milk products in the daily diet, this study was undertaken to assess the consumption of milk and milk products among the inhabitants of the Upper Silesian agglomeration.Design: The survey covered 600 people, including 339 women (56.5%) and 261 men (43.5%) a...

  8. Study of agglomeration behavior of combustion-synthesized nano-crystalline ceria using new fuels

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, Srirupa T.; Bedekar, Vinila [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra (India); Patra, A.; Sastry, P.U. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra (India); Tyagi, A.K. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra (India)], E-mail: aktyagi@barc.gov.in

    2008-10-20

    Ceria powders were prepared by gel combustion process using cerium nitrate and hitherto unexplored amino acid fuels such as aspartic acid, glutamic acid, arginine, tryptophan, phenyl alanine, valine, etc. These powders were characterized by X-ray diffraction, surface area analysis, sinterability, dynamic light scattering, scanning electron microscopy (SEM) and small angle X-ray scattering (SAXS). The combustion-synthesized powders were agglomerates of nano-crystallites. SAXS profiles of the powders prepared using tryptophan, phenyl alanine and dimethyl urea exhibited fractal behavior.

  9. Agglomeration externalities, market structure and employment growth in high-tech industries: Revisiting the evidence

    Directory of Open Access Journals (Sweden)

    Cieślik Andrzej

    2015-09-01

    Full Text Available In this paper we revisit the existing empirical evidence on the effects of various agglomeration externalities and the market structure on employment growth in the high-tech industries of the European Economic Area (EEA. Our study is based on the dynamic panel dataset of two-digit NACE rev 1.1. industries in 285 regions of the European Economic Area for the period 1995-2007. We find that employment growth is negatively related to competition, while localization and urbanization externalities do not seem to affect growth.

  10. Quasi-two-dimensional complex plasma containing spherical particles and their binary agglomerates

    CERN Document Server

    Chaudhuri, M; Nosenko, V; Thomas, H M

    2015-01-01

    A new type of quasi-two-dimensional complex plasma system was observed which consisted of monodisperse microspheres and their binary agglomerations (dimers). The particles and their dimers levitated in a plasma sheath at slightly different heights and formed two distinct sublayers. The sys- tem did not crystallize and may be characterized as disordered solid. The dimers were identified based on their characteristic appearance in defocused images, i.e., rotating interference fringe pat- terns. The in-plane and inter-plane particle separations exhibit nonmonotonic dependence on the discharge pressure which agrees well with theoretical predictions.

  11. Nanoparticle agglomerates of indomethacin: The role of poloxamers and matrix former on their dissolution and aerosolisation efficiency.

    Science.gov (United States)

    Malamatari, Maria; Somavarapu, Satyanarayana; Bloxham, Mark; Buckton, Graham

    2015-11-10

    Nanoparticles (NPs) were prepared and assembled to microsized agglomerates with and without matrix formers (mannitol and L-leucine) by coupling wet milling and spray drying to harmonise the advantages of NPs with handling and aerodynamics of microparticles without induction of amorphisation. Indomethacin was selected as poorly water-soluble drug and poloxamers with different ratios of hydrophilic to hydrophobic domains were evaluated as stabilisers comparatively to D-α-Tocopherol polyethylene-glycol succinate (TPGS). Particle size of nanosuspensions and morphology, size, crystal form, drug loading, redispersibility, in vitro dissolution, and in vitro aerosolisation of NP-agglomerates were determined. Molecular weight of stabilisers affected the rate but not the limit of NP size reduction and the length of hydrophilic segment in poloxamers was found important for the nanosuspension stabilisation. SEM revealed the structure of agglomerates consisting of nanocrystal assemblies. XRPD with DSC proved that NP agglomerates retained their crystallinity. NP-agglomerates exhibited enhanced dissolution compared to physical mixtures of drug and stabilisers while incorporation of matrix formers enabled redispersibility upon hydration and further increased the drug dissolution. Also, matrix formers resulted in significantly improved aerosolisation with higher fine particle fractions (49-62%) and smaller mass median aerodynamic diameters (<3.5 μm), compared to cases without matrix formers (34-43% and <4.5 μm). PMID:26364709

  12. De-agglomeration Effect of the US Pharmacopeia and Alberta Throats on Carrier-Based Powders in Commercial Inhalation Products.

    Science.gov (United States)

    Leung, Sharon Shui Yee; Tang, Patricia; Zhou, Qi Tony; Tong, Zhenbo; Leung, Cassandra; Decharaksa, Janwit; Yang, Runyu; Chan, Hak-Kim

    2015-11-01

    The US pharmacopeia (USP) and Alberta throats were recently reported to cause further de-agglomeration of carrier-free powders emitted from some dry powder inhalers (DPIs). This study assessed if they have similar influences on commercially available carrier-based DPIs. A straight tube, a USP throat, and an Alberta throat (non-coated and coated) were used for cascade impaction testing. Aerosol fine particle fraction (FPF ≤ 5 μm) was computed to evaluate throat-induced de-agglomeration. Computational fluid dynamics are employed to simulate airflow patterns and particle trajectories inside the USP and Alberta throats. For all tested products, no significant differences in the in vitro aerosol performance were observed between the USP throat and the straight tube. Using fine lactose carriers (10 μm), impaction frequency and energy inside the Alberta throat were significant. Further de-agglomeration was noted inside the non-coated Alberta throat for Seretide(®) and Spiriva(®), but agglomerates emitted from Relenza(®), Ventolin(®), and Foradil(®) did not further break up into smaller fractions. The coated Alberta throat considerably reduced the FPF values of these products due to the high throat retention, but they generally agreed better with the in vivo data. In conclusion, depending on the powder formulation (including carrier particle size), the inhaler, and the induction port, further de-agglomeration could happen ex-inhaler and create differences in the in vitro measurements. PMID:26201967

  13. THE INFLUENCE OF FIRMS STRUCTURAL CHARACTERISTICS ON THE DEGREE OF AGGLOMERATION ECONOMIES ENJOYED AMONGST FIRMS IN THE LAGOS REGION, NIGERIA

    Directory of Open Access Journals (Sweden)

    FAGBOHUNKA Adejompo

    2015-12-01

    Full Text Available Agglomeration economies is a potent tool in socio-economic revamping, rejuvenation and sustenance of regions, this is as a result of the impulse it transmitted through the multiplier effect it is capable of generated. Therefore, this paper underscores the influence of firms structural characteristics on the degree of agglomeration economies enjoyed amongst firms, using the Lagos region as a case study. The first stage in the collection of primary data involves the reconnaissance survey, thereafter one hundred and three questionnaire were administered in twelve industrial estates; one questionnaire in each of the firm. The paper reveals the following structural characteristics as germane to industrial enterprise; age of firms, areal plant size (m², capacity utilization (in percentage, and Labour size and firms investment. The paper has also found out those agglomeration economies enjoyed ranges from transportation, labour, power supply, to joint water supply. The Roy’s Largest Root test employed to test for the significance of the canonical correlations at 0.05 significant levels shows the calculated F-value 3.5247 and the tabulated F-value 2.90. This suggests that the degree of agglomeration economies enjoyed by firms is significantly explained by the size and structural characteristics of the firms. The paper therefore recommends more and active government participation in the industrial scene, given the necessary support for the expansion of firm’s structural characteristics which will lead to increase agglomeration economies enjoyed by these firms.

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

    Science.gov (United States)

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

    2016-05-01

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

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

    Science.gov (United States)

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

    2016-08-01

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

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

    International Nuclear Information System (INIS)

    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. (paper)

  17. Environmental influence of Wuhan urban agglomeration development and strategies of environmental protection

    Institute of Scientific and Technical Information of China (English)

    GAO Qun; LIU Ying-tao; MAO Han-ying

    2006-01-01

    In Wuhan urban agglomeration (WUA), the population growth and concentration, the industrial development and urban sprawl have been affecting the environment fundamentally. Comparing with Yangtze delta metropolitan region, the level of urbanization and industrialization of WUA has lagged behind for about 10 years; but the problems in environmental protection and rehabilitation are commonly serious. In the future, WUA should avoid unnecessary mistakes and seek a win-win strategy for economy and environment in its large-scale development stage. Based on the analysis of the changing of main environmental pollutants and the coupled curves in past decades, the paper discussed the important links among the urban environmental pollutions, industry growth and urban sprawl in WUA. It is concluded that the integration of economic and environmental policies in urban development is more required and significant at the large urban agglomeration region. Four proactive and long-term strategies need to be adopted to provide prior guidance and better protection for the development of WUA.

  18. Consumption of milk and milk products in the population of the Upper Silesian agglomeration inhabitants

    Directory of Open Access Journals (Sweden)

    Marek Kardas

    2016-03-01

    Full Text Available Background: Providing the appropriate amount of nutrients at every stage of life is a key element determining the proper development and functioning of the body. Objective: Because of the nutritional value and resulting position of milk and milk products in the daily diet, this study was undertaken to assess the consumption of milk and milk products among the inhabitants of the Upper Silesian agglomeration. Design: The survey covered 600 people, including 339 women (56.5% and 261 men (43.5% aged 18–78 years. To assess the consumption of milk and milk products, as a research tool an original survey with the closed-ended and open-ended questions was used. The questions concerned the characteristics of the surveyed group and various aspects of the consumption of milk and milk products. The results obtained were subjected to statistical analysis using the Statistica 10.0 program with a chi-square test for quality features. Results: The level of consumption of milk and milk products among the Upper Silesian agglomeration inhabitants is insufficient in relation to nutrition recommendations. However, despite many controversies surrounding milk, the respondents also claimed that it played an important role in their daily diet. Conclusions: The most frequently consumed type of milk in the surveyed group is ultra heat treated (UHT milk with average fat content.

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

    Science.gov (United States)

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

    2012-10-01

    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.

  20. Remediation of a heavy metal-contaminated soil by means of agglomeration.

    Science.gov (United States)

    Polettini, Alessandra; Pomi, Raffaella; Valente, Mattia

    2004-01-01

    The feasibility of treating a heavy metal-contaminated soil by means of a solidification/stabilization treatment consisting of a granulation process is discussed in the present article. The aim of the study was to attain contaminant immobilization within the agglomerated solid matrix. The soil under concern was characterized by varying levels of heavy metal contamination, ranging from 50 to 500 mg kg(-1) dry soil for chromium. from 300 to 2000 mg kg(-1) dry soil for lead and from 270 to 5000 mg kg(-1) dry soil for copper. An artificially contaminated soil with contaminant concentrations corresponding to the upper level of the mentioned ranges was prepared from a sample of uncontaminated soil by means of spiking experiments. Pure soluble species of chromium, copper and lead. namely CrCl3.6H2O, CuCl2.2H2O and Pb(NO3)2, were selected for the spiking experiments, which were arranged according to a 2(3) full factorial design. The solidification/stabilization treatment was based on an agglomeration process making use of hydraulic binders including Portland cement, hydrated lime and sodium methasilicate, which were selected on the basis of preliminary test runs. It was found that after 7 days of curing the applied treatment was able to efficiently immobilize the investigated heavy metals within the hydrated matrix. Good acid neutralization behavior was also observed, indicating improved matrix resistance to acid attack and decreased potential for metal leaching. PMID:15137715

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

    International Nuclear Information System (INIS)

    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

  2. Agglomeration, sedimentation, and cellular toxicity of alumina nanoparticles in cell culture medium

    International Nuclear Information System (INIS)

    The cytotoxicity of alumina nanoparticles (NPs) was investigated for a wide range of concentration (25–200 μg/mL) and incubation time (0–72 h) using floating cells (THP-1) and adherent cells (J774A.1, A549, and 293). Alumina NPs were gradually agglomerated over time although a significant portion of sedimentation occurred at the early stage within 6 h. A decrease of the viability was found in floating (THP-1) and adherent (J774A.1 and A549) cells in a dose-dependent manner. However, the time-dependent decrease in cell viability was observed only in adherent cells (J774A.1 and A549), which is predominantly related with the sedimentation of alumina NPs in cell culture medium. The uptake of alumina NPs in macrophages and an increased cell-to-cell adhesion in adherent cells were observed. There was no significant change in the viability of 293 cells. This in vitro test suggests that the agglomeration and sedimentation of alumina NPs affected cellular viability depending on cell types such as monocytes (THP-1), macrophages (J774A.1), lung carcinoma cells (A549), and embryonic kidney cells (293).

  3. Environmental influence of Wuhan urban agglomeration development and strategies of environmental protection.

    Science.gov (United States)

    Gao, Qun; Liu, Ying-Tao; Mao, Han-Ying

    2006-01-01

    In Wuhan urban agglomeration (WUA), the population growth and concentration, the industrial development and urban sprawl have been affecting the environment fundamentally. Comparing with Yangtze delta metropolitan region, the level of urbanization and industrialization of WUA has lagged behind for about 10 years; but the problems in environmental protection and rehabilitation are commonly serious. In the future, WUA should avoid unnecessary mistakes and seek a win-win strategy for economy and environment in its large-scale development stage. Based on the analysis of the changing of main environmental pollutants and the coupled curves in past decades, the paper discussed the important links among the urban environmental pollutions, industry growth and urban sprawl in WUA. It is concluded that the integration of economic and environmental policies in urban development is more required and significant at the large urban agglomeration region. Four proactive and long-term strategies need to be adopted to provide prior guidance and better protection for the development of WUA. PMID:17294667

  4. STUDY ON ECOLOGICAL SPACE OF URBAN AGGLOMERATION--Taking Wuxi City as an Example

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    From the angle of ecology, urban agglomeration presents relevant types of landscape structure, which in-clude Patch, Corridor and Matrix. There are different landscape features and different problems in different developmentphases. This paper has put forward five basic conditions for security pattern of landscape ecology of urban agglomeration,described quantitatively the features for landscape ecology in Wuxi, and analyzed ecological background of spatial expan-sion and spatial organization of urban development in Wuxi. From the angle of ecological land use and non-ecological landuse, the paper has analyzed the features of land use and ecological distribution of land in the urban area. The spatial mod-el of cities and towns in Wuxi is composed of one metropolis, two urban zones and three development axes. This thesishas planned preliminarily ecological protection network at four levels in the urban region according to four layers. At last,combining landscape ecology with urban space, a tentative security pattern of landscape ecology has been p1anned in Wux-i, namely Source-Buffer Zone and Metropolis, Radiating Routes and Expansion Direction of City, Strategic Point and Interac-tion between Cities and Towns, Inter-Source Linkage-Corridor of a Stable Landscape Structure.

  5. Low-agglomerated yttria nanopowders via decomposition of sulfate-doped precursor with transient morphology

    Institute of Scientific and Technical Information of China (English)

    R.P. Yavetskiy; D.Yu. Kosyanov; V.N. Baumer; A.G. Doroshenko; A.I. Fedorov; N.A. Matveevskaya; A.V. Tolmachev; O.M. Vovk

    2014-01-01

    The fabrication peculiarities of low-agglomerated yttria (Y2O3) nanopowders via thermal decomposition of sulfate-doped precursor with transient morphology were studied. It was determined that Y2(OH)5(NO3)x(CO2)y(SO4)z·nH2O (n=1-2) crystalline precursor underwent fragmentation and decomposition into isolated quasi-spherical Y2O3 particles upon calcination. Effect was con-nected with minimizing the free energy of the plate-like crystallites via reducing the contact surface until to the moment of spheroidi-zation and attainment of isolation that occurred atТ=1100 °С. Residual sulfate ions slowed down the surface diffusion during heat treatment thus retaining quasy-spherical morphology and low aggregation degree of Y2O3 nanopowders. Sulfate-doped yttria nanopowders with medium particle size of 53±13 nm possessed improved sinterability in comparison with undoped ones arising from finer particle size, narrower particle distribution and lower agglomeration degree.

  6. Experimental study on size-dependency of effective permittivity of particle-gas mixture with agglomeration

    Institute of Scientific and Technical Information of China (English)

    Li Xiaomin; Xu Lijun; Li Songyun

    2007-01-01

    The effective medium approximation (EMA) theory is the basis of a capacitance sensor used for concentration measurement of a particulate solid flow, its measurement result is independent on particle size. In existence of particle agglomeration or aggradation, however, it is found that the effective permittivity of a gas/solid mixture is dependent on particle size. In this paper, a parallel plate, differential capacitance sensor is utilized to investigate the influence of particle size on the effective permittivity of the mixture in such a case. Static experiments using three materials including glass, limestone and quartz particles were carried out in an off-line manner. The volume fraction of particles being tested ranged from 20×10-6 to 600×10-6, while the particle size was between 3 and 100 μm. Experimental results show that the effective permittivity of a particle-gas mixture with particle agglomeration is larger than that predicted by EMA and the smaller the particle size, the larger the effective permittivity. The experiment process and analysis results are discussed in detail in the paper.

  7. Study of ink paper sensor based on aluminum/carbon nanotubes agglomerated nanocomposites.

    Science.gov (United States)

    dos Reis, Marcos A L; Saraiva, Augusto F; Vieira, Manuel F G; Del Nero, Jordan

    2012-09-01

    Agglomerated nanocomposites based on Aluminum/Carbon Nanotubes (AI/CNT) were produced by an arc discharge technique under argon/acetone atmosphere and ultrasonically dispersed in distilled water to form an ink-like composite. This ink was spread onto commercial paper to produce a conductive thick film. Experimental results show that the electrical resistance of Al/CNT nanocomposite on paper changes when a mechanical stress and/or heat is applied. The multi-sensory properties obtained are the following: (i) piezoresistive effect, electrical resistance shows linear dependence with pressure intensity at room temperature; (ii) polynomial relationship between electrical resistance and temperature; and (iii) high accuracy thermal sensor compared to a K type thermocouple at 25 degrees C. The nanocomposite and paper morphology was analyzed by Scanning Electron Microscopy with Energy Dispersive Spectrometry (SEM/EDS) and a favorable surface for physisorption was observed. Transmission Electron Microscopy (TEM) was utilized for Al/CNT agglomerated indicating that the ink paper based on nanocomposite shows good performance as a thermo-piezoresistive sensor. PMID:23035420

  8. Study on transfer-free graphene synthesis process utilizing spontaneous agglomeration of catalytic Ni and Co metals

    International Nuclear Information System (INIS)

    Transfer-free graphene synthesis process utilizing metal agglomeration phenomena was investigated by using carbon films deposited on Ni or Co catalyst metals on SiO2/Si substrates. As a result of metal agglomeration at high temperatures, multilayer graphene films appeared to be formed directly on SiO2 films. The microscopic Raman mapping study revealed that graphene films were preferentially synthesized around areas where metal films disappeared at an early stage of agglomeration, and that they finally covered almost the whole surface. It was also found that the synthesized graphene films tended to have better structural qualities and lower layer numbers with the increase in the starting metal thicknesses regardless of the kinds of catalyst metals. Raman study also showed that they had good two-dimensional uniformity in the structural quality. (paper)

  9. Basic principles and mechanisms of selective oil agglomeration. Fossil energy interim report, October 1, 1983--September 30, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Wheelock, T.D.

    1992-12-31

    Numerous agglomeration tests were conducted with several types of low-ash coal and graphite, high grade mineral pyrite, and other materials. Relatively pure hydrocarbons, including heptane and hexadecane, were used as agglomerants. Access of air to the system was controlled. Particle recovery by agglomeration was observed to depend on a number of system parameters. Among the most important parameters are the hydrophobicity of the particles and the oil dosage, so that the, recovery of solids per unit of oil administered is proportional to the hydrophobicity. The pH and ionic strength of the aqueous suspension affect particle recovery in different ways depending on the surface properties of the particles. On the other hand, the presence of air in the system generally improves particle recovery. The greatest effect of air was observed in a closely related study which showed that air had to be present to produce good agglomerates from a moderately hydrophobic coal in a mixer producing a lower shear rate. The rate of agglomeration was found to be much greater for a strongly hydrophobic coal than for a moderately hydrophobic coal, and the rate was observed to be proportional to the oil dosage. Also the rate was enhanced by the presence of air in the, system. For hydrophobic coals, the rate increased with increasing ionic strength of the aqueous medium, but it was not affected greatly by pH over a wide range. The separation of coal and pyrite particles by selective agglomeration was found to depend on the relative hydrophobicity of the materials, the oil dosage, and the properties of the aqueous medium.

  10. The optimization of the quantity of coke and agglomerate in lead production in “Water-Jacket” furnace

    Directory of Open Access Journals (Sweden)

    E. Haxhiaj

    2012-01-01

    Full Text Available The dependence of technical lead production on the composition of the agglomerate has been analyzed on “Water-Jacket” furnace in Trepça. Additionally, the theoretical and real raport of coke consumption per ton of technical lead was studied. The goal of this study was to optimize the parameters of the process with respect to the amount of technical lead produced, the amounts of lead in the agglomerate and the air in the furnace. Special attention was also placed on minimization of energy consumption and environmental pollution.

  11. Optical detection of nanoparticle agglomeration in a living system under the influence of a magnetic field

    International Nuclear Information System (INIS)

    Nanoparticles are important in diagnosis and therapy. In order to apply their potential, an understanding of the behavior of particles in the body is crucial. However, in vitro experiments usually do not mimic the dynamic conditions of the in vivo situation. The aim of our work was an in vivo observation of particle transport in chicken egg vessels in the presence of a magnetic field by particle tracking. For that we demonstrate the spatial resolution of our observations in a vein and a temporal resolution by observation of the cardiac cycle in an artery. Microscopic images were recorded in dark field reflection and fluorescence mode. - Highlights: • Optically accessible blood circulation in hen's egg CAV model. • Observation of transport of magnetic particles in chicken egg vessels. • Irreversibility of agglomerates after removing the magnetic field

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

    International Nuclear Information System (INIS)

    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

  13. Measuring socio-economic inequality: From dwellers' perspective within Bangalore urban agglomeration

    Directory of Open Access Journals (Sweden)

    Keya Chakraborty

    2015-06-01

    Full Text Available Planners and researchers have realized that larger regional framework of urban areas are significant in assessing various inequality aspects in a developing country like India. The framework consists of heterogeneity in spatial and demographic aspects and in quality of socio-economic development levels as well. Against this background, the present paper has proposed a methodological framework to assess socio-economic inequality within Bangalore Urban Agglomeration (BUA as governed by the composite set of Human Development Index (HDI based indicators. Assessments are based on local data of dwellers' preferences on the indicators. On the whole, this paper has tried to establish the significance of application of HDI based indicators in an assessment of socio-economic inequality within BUA. Consequently, the paper has arrived at the need for improvement of comprehensive HDI governed basic public services, amenities, and advanced facilities, across all trans-urban-area levels to ensure a holistic development within BUA.

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

    Science.gov (United States)

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

    2014-03-15

    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

  15. Optical detection of nanoparticle agglomeration in a living system under the influence of a magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Müller, Robert, E-mail: robert.mueller@ipht-jena.de [Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena (Germany); Stranik, Ondrej [Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena (Germany); Schlenk, Florian; Werner, Sebastian [Department of Pharmaceutical Technology, Institute of Pharmacy, Friedrich Schiller University, Otto-Schott-Str. 41, 07745 Jena (Germany); Malsch, Daniéll [Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena (Germany); Fischer, Dagmar [Department of Pharmaceutical Technology, Institute of Pharmacy, Friedrich Schiller University, Otto-Schott-Str. 41, 07745 Jena (Germany); Fritzsche, Wolfgang [Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena (Germany)

    2015-04-15

    Nanoparticles are important in diagnosis and therapy. In order to apply their potential, an understanding of the behavior of particles in the body is crucial. However, in vitro experiments usually do not mimic the dynamic conditions of the in vivo situation. The aim of our work was an in vivo observation of particle transport in chicken egg vessels in the presence of a magnetic field by particle tracking. For that we demonstrate the spatial resolution of our observations in a vein and a temporal resolution by observation of the cardiac cycle in an artery. Microscopic images were recorded in dark field reflection and fluorescence mode. - Highlights: • Optically accessible blood circulation in hen's egg CAV model. • Observation of transport of magnetic particles in chicken egg vessels. • Irreversibility of agglomerates after removing the magnetic field.

  16. Stability of Spatial Structure of Urban Agglomeration in China Based on Central Place Theory

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper brings forward the concept of stability of the spatial structure of urban agglomeration (UA) based on Central Place Theory by introducing centrality index and fractal theory. Before assessment, K=4 is selected as parameter to calculate centrality index and fractal dimension (K represents the quantitive relationship between city and the counties in Central Place Theory), and then found the number of nodes, the type of spatial structure, the spatial allocation of nodes with different hierarchy affecting the stability of spatial structure. According to spatial contact direction and the level of stability, UAs in China are classified into five types. Finally, it is posed as a further question that how to use hierarchical relation K=6 and K=7 in central place system to coordinate with the assessment of stability of spatial structure is brought forward.

  17. Charge and agglomeration dependent in vitro uptake and cytotoxicity of zinc oxide nanoparticles.

    Science.gov (United States)

    Abdelmonem, Abuelmagd M; Pelaz, Beatriz; Kantner, Karsten; Bigall, Nadja C; Del Pino, Pablo; Parak, Wolfgang J

    2015-12-01

    The influence of the surface charge and the state of agglomeration of ZnO nanoparticles on cellular uptake and viability are investigated. For this purpose, ZnO nanoparticles were synthesized by colloidal routes and their physicochemical properties were investigated in detail. Three different surface modifications were investigated, involving coatings with the amphiphilic polymer poly(isobutylene-alt-maleic anhydride)-graft-dodecyl, mercaptoundecanoic acid, and L-arginine, which provide the nanoparticles with either a negative or a positive zeta-potential. The hydrodynamic diameters and zeta-potentials of all three nanoparticle species were investigated at different pH values and NaCl concentrations by means of dynamic light scattering and laser Doppler anemometry, respectively. The three differently modified ZnO nanoparticle species of similar sizes were also investigated in respect to their cellular uptake by 3T3 fibroblasts and HeLa cells, and their effect on cell viability. PMID:26387023

  18. Utility assessment of human development indicators: Case of Kolkata Urban agglomeration

    Directory of Open Access Journals (Sweden)

    Keya Chakraborty

    2011-06-01

    Full Text Available The present paper attempts to establish a set of variables to find out the extent and levels of inequality in Human Development Indicators (HDIs driven development based on a geographic delineation of Kolkata Urban Agglomeration (KUA. The study is based on the geographic delineation of the region of KUA. Given this background, it assesses health, education and economic scenario of the study area by variables of rates of mortality, literacy and working population, respectively. For the purpose of analysis, initially percentage distributions of variables over the study area have been computed and subsequently, assessed through Gini's Coefficient, which is an indicator of inequality in distribution over a geographic space. Then reviews of variations by virtue of spatial aggregation and disaggregation in the form of agglomerations of core vis-'-vis periphery, east bank versus west bank differentials have been presented. The analysis is supplemented by correlation studies. United Nations Development Program (UNDP supports the fact that inequalities in development can be better addressed through assessment of qualitative indicators of Human Development Index. This very concept is also reflected in recent urban development researches conducted by organizations like Indian Council for Research on International Economic Relations (ICRIER, 2010, National Council of Applied Economic Research (NCAER, 2009 and London School of Economics (LSE, 2009. The organizations suggest that the holistic objective of India's metropolitan development can be best approached if objectives of minimization of income based inequalities proceed in its multiple dimensions like Human Development Indicators (HDIs. The present paper attempts to meet such goals in the perspective of KUA.

  19. The influence of cluster type economic agglomerations on the entrepreneurship, in Romania

    Directory of Open Access Journals (Sweden)

    Adriana REVEIU

    2012-12-01

    Full Text Available Regional clusters and entrepreneurship have become very popular research topic in many areas, such as: economics, regional science, and economic geography.A large number of scientific papers published in the last years investigate the empirical evidence for clusters, their definition, and their implications for economic policy. Also, a series of working tools for regional cluster analyses have been proposed.Entrepreneurial activities interact and their characteristics are normally bound to the region. Entrepreneurial activities take place in interaction with other economic activities conducted at the local level, and the interaction between them can be the starting point of an economic cluster.There are lots of arguments for the hypothesis that existing regional clusters have positive impact on the entrepreneurial activities. But only few analyses exist referring to the relationship between clusters attributes of a region and the entrepreneurial activities in the same region. From my knowledge, it is not such of analyses about Romania.This paper aims to identify regions with potential industrial clusters, from Romania, and to analyse their impact on the entrepreneurial environment. Data about all the companies acting in Romania, in 2011 are used to elaborate the spatial clusters in the most concentrated Romania industries. A second data set with information about new establishments in last year is used, from the National Trade Register Office statistics. This data set serves to assess the relationship between regional clusters and entrepreneurial activities. The paper tests the empirically proven hypothesis which stipulates that the existence of one or several cluster type agglomerations in a region has a positive impact on the number of start-ups in the same region.The results obtained from descriptive and regression analyses have shown that there is a positive relationship between the number of cluster type agglomerations and the

  20. Fluidized-Bed Coating with Sodium Sulfate and PVA-TiO2, 2. Influence of Coating Solution Viscosity, Stickiness, pH, and Droplet Diameter on Agglomeration

    DEFF Research Database (Denmark)

    Hede, Peter Dybdahl; Bach, Poul; Jensen, Anker Degn

    2009-01-01

    In the first part of this study [Hede, P. D.; Bach, P.; Jensen, A. D. Ind. Eng. Chem. Res. 2009, 49, 1914], agglomeration regime maps were developed for two types of coatings: sodium sulfate and PVA-TiO2. It was observed here how the agglomeration tendency is always lower for the salt coating...

  1. World Urbanization Prospects: The 1992 Revision. Estimates and Projections of Urban and Rural Populations and of Urban Agglomerations.

    Science.gov (United States)

    United Nations New York, NY. Dept. of Economic and Social Information and Policy Analysis.

    This United Nation's publication presents data on the size and growth of urban and rural populations for all countries of the world and contains revised estimates and projections for all urban agglomerations that had at least one million inhabitants in 1990. Chapter 1 presents levels of urbanization and future trends for urban and rural…

  2. Development and validation of conservative-mechanistic and best estimate approaches to quantifying mass fractions of agglomerated debris

    International Nuclear Information System (INIS)

    Ex-vessel termination of accident progression in Swedish type Boiling Water Reactors (BWRs) is contingent upon efficacy of melt fragmentation, quenching, solidification and formation of a coolable by natural circulation porous debris bed in a deep pool of water below reactor vessel. When liquid melt reaches the bottom of the pool it can cause formation of agglomerated debris and “cake” regions, which affect hydraulic resistance and thus coolability of the bed. This paper discusses development and validation of conservative-mechanistic and best estimate approaches to quantifying mass fractions of agglomerated debris at given conditions of melt release from the vessel. Fuel–coolant interaction (FCI) code VAPEX-P is used as a computational vehicle for modeling. Experimental data from the DEFOR-A (Debris Bed Formation and Agglomeration) tests with binary oxidic simulant material melt is used for validation of developed methods. The paper discusses the influence of different inherent uncertainties in the prediction of the fraction of agglomerated debris

  3. Micro-evidence on the determinants of innovation in the Netherlands : The relative importance of absorptive capacity and agglomeration externalities

    NARCIS (Netherlands)

    Smit, Martijn J.; Abreu, Maria A.; de Groot, Henri L. F.

    2015-01-01

    Although the benefits of clustering for innovation have received much attention in the theoretical as well as empirical literature, analyses at the regional level often disregard the characteristics of local firms. We tackle both at the same time: agglomeration externalities (Marshall, Porter, Jacob

  4. Chemically mediated diffusion of d-metals and B through Si and agglomeration at Si-on-Mo interfaces

    NARCIS (Netherlands)

    T. Tsarfati,; Zoethout, E.; van de Kruijs, R.; F. Bijkerk,

    2009-01-01

    Chemical diffusion and interlayer formation in thin layers and at interfaces is of increasing influence in nanoscopic devices, such as nanoelectronics and reflective multilayer optics. Chemical diffusion and agglomeration at interfaces of thin Ru, Mo, Si, and B4C layers have been studied with x-ray

  5. 2D Cross Sectional Analysis and Associated Electrochemistry of Composite Electrodes Containing Dispersed Agglomerates of Nanocrystalline Magnetite, Fe₃O₄.

    Science.gov (United States)

    Bock, David C; Kirshenbaum, Kevin C; Wang, Jiajun; Zhang, Wei; Wang, Feng; Wang, Jun; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S

    2015-06-24

    When electroactive nanomaterials are fully incorporated into an electrode structure, characterization of the crystallite sizes, agglomerate sizes, and dispersion of the electroactive materials can lend insight into the complex electrochemistry associated with composite electrodes. In this study, composite magnetite electrodes were sectioned using ultramicrotome techniques, which facilitated the direct observation of crystallites and agglomerates of magnetite (Fe3O4) as well as their dispersal patterns in large representative sections of electrode, via 2D cross sectional analysis by Transmission Electron Microscopy (TEM). Further, the electrochemistry of these electrodes were recorded, and Transmission X-ray Microscopy (TXM) was used to determine the distribution of oxidation states of the reduced magnetite. Unexpectedly, while two crystallite sizes of magnetite were employed in the production of the composite electrodes, the magnetite agglomerate sizes and degrees of dispersion in the two composite electrodes were similar to each other. This observation illustrates the necessity for careful characterization of composite electrodes, in order to understand the effects of crystallite size, agglomerate size, and level of dispersion on electrochemistry. PMID:26024206

  6. Probing dispersion and re-agglomeration phenomena upon melt-mixing of polymer-functionalized graphite nanoplates.

    Science.gov (United States)

    Santos, R M; Vilaverde, C; Cunha, E; Paiva, M C; Covas, J A

    2016-01-01

    A one-step melt-mixing method is proposed to study dispersion and re-agglomeration phenomena of the as-received and functionalized graphite nanoplates in polypropylene melts. Graphite nanoplates were chemically modified via 1,3-dipolar cycloaddition of an azomethine ylide and then grafted with polypropylene-graft-maleic anhydride. The effect of surface functionalization on the dispersion kinetics, nanoparticle re-agglomeration and interface bonding with the polymer is investigated. Nanocomposites with 2 or 10 wt% of as-received and functionalized graphite nanoplates were prepared in a small-scale prototype mixer coupled to a capillary rheometer. Samples were collected along the flow axis and characterized by optical microscopy, scanning electron microscopy and electrical conductivity measurements. The as-received graphite nanoplates tend to re-agglomerate upon stress relaxation of the polymer melt. The covalent attachment of a polymer to the nanoparticle surface enhances the stability of dispersion, delaying the re-agglomeration. Surface modification also improves interfacial interactions and the resulting composites presented improved electrical conductivity. PMID:26439171

  7. [Sonic Enhanced Ash Agglomeration and Sulfur Capture]. [Quarterly technical progress report, September 27, 1993--January 2, 1994

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-31

    A major concern with the utilization of coal in directly fired gas turbines is the control of particulate emissions and reduction of sulfur dioxide, and alkali vapor from combustion of coal, upstream of the gas turbine. The Sonic Enhanced Ash Agglomeration and Sulfur Capture program focuses upon the application of an MTCI proprietary invention (Patent No. 5,197,399) for simultaneously enhancing sulfur capture and particulate agglomeration of the combustor effluent. This application can be adapted as either a ``hot flue gas cleanup`` subsystem for the current concepts for combustor islands or as an alternative primary pulse combustor island in which slagging, sulfur capture, particulate agglomeration and control, and alkali gettering as well as NO{sub x} control processes become an integral part of the pulse combustion process. The goal of the program is to support the DOE mission in developing coal-fired combustion gas turbines. In particular, the MTCI proprietary process for bimodal ash agglomeration and simultaneous sulfur capture will be evaluated and developed. The technology embodiment of the invention provides for the use of standard grind, moderately beneficiated coal and WEM for firing the gas turbine with efficient sulfur capture and particulate emission control upstream of the turbine. The process also accommodates injection of alkali gettering material if necessary. This is aimed at utilization of relatively inexpensive coal fuels, thus realizing the primary benefit being sought by direct firing of coal in such gas turbine systems.

  8. Improved dissolution and micromeritic properties of naproxen from spherical agglomerates: preparation, in vitro and in vivo characterization

    Directory of Open Access Journals (Sweden)

    Damineni Saritha

    2012-12-01

    Full Text Available Naproxen, an anti-inflammatory drug, exhibits poor aqueous solubility, which limits the pharmacological effects. The present work was carried out to study the effect of agglomeration on micromeritic properties and dissolution. Naproxen agglomerates were prepared by using a three solvents system composed of acetone (good solvent, water (non-solvent and dichloromethane (bridging liquid. Differential Scanning Calorimetry (DSC results showed no change in the drug after crystallization process. X-Ray Powder Diffraction (XRPD studies showed the sharp peaks are present in the diffractograms of spherical agglomerates with minor reduction in height of the peaks. The residual solvents are largely below the tolerated limits in the agglomerates. Scanning Electronic Microscopy (SEM studies showed that agglomerates were spherical in structure and formed by cluster of small crystals. The agglomerates exhibited improved solubility, dissolution rate and micromeritic properties compared to pure drug. Anti-inflammatory studies were conducted in Wistar strain male albino rats and naproxen agglomerates showed more significant activity than the pure drug.Naproxeno, fármaco anti-inflamatório, apresenta baixa solubilidade em água, o que limita os efeitos farmacológicos. O presente trabalho foi realizado para estudar o efeito da aglomeração nas propriedades micromeríticas e na dissolução. Aglomerados de naproxeno foram preparados por meio da utilização de sistema de três solventes composto de acetona (bom solvente, água (não-solvente e diclorometano (líquido de ligação. A DSC não resulta mostrou nenhuma mudança na droga depois de processo de cristalização. Estudos de difração de Raios X do Pó (XRPD mostraram picos agudos nos difratogramas de aglomerados esféricos, com redução mínima dea altura dos picos. Os solventes residuais estão amplamente abaixo dos limites tolerados nos aglomerados. Os estudos de Microscopia Eletrônica de Varredura

  9. Research approach and first results on agglomerate compaction in protoplanetary dust simulation in the Cloud Manipulation System

    Science.gov (United States)

    Vedernikov, Andrei; Blum, Jurgen; Ingo Von Borstel, Olaf; Schraepler, Rainer; Balapanov, Daniyar; Cecere, Anselmo

    2016-07-01

    Nanometre and micrometre-sized solid particles are ubiquitous in space and on Earth - from galaxies, interstellar space, protoplanetary and debris disks to planetary rings and atmospheres, planetary surfaces, comets, interplanetary space, Earth's atmosphere. Apparently, the most intriguing problem in the picture of the formation of planets is the transition from individual microscopic dust grains to kilometre-sized planetesimals. Revealing the mechanisms of this transition is one of the main tasks of the European Space Agency's project Interaction in Cosmic and Atmospheric Particle Systems (ICAPS). It was found that Brownian motion driven agglomeration could not provide the transition within reasonable time scale. As a result, at this stage top scientific goals shifted towards forced agglomeration and concentration of particles, targeting revealing the onset of compaction, experimental study of the evolution of fractal dimensions, size and mass distribution, occurrence of bouncing. The main tasks comprise 1) development of the rapid agglomeration model 2) development of the experimental facilities creating big fractal-type agglomerates from 10 to 1000 μm from a cloud of micrometre-size grains; 3) experimental realization of the rapid agglomeration in microgravity and ground conditions; and 4) in situ investigation of the morphology, mobility, mechanical and optical properties of the free-floating agglomerates, including investigation of thermophoresis, photophoresis of the agglomerates and of the two-phase flow phenomena. To solve the experimental part of the tasks we developed a Cloud Manipulation System, realized as a breadboard (CMS BB) for long duration microgravity platforms and a simplified laboratory version (CMS LV) mostly oriented on short duration microgravity and ground tests. The new system is based on the use of thermophoresis, most favourable for cloud manipulation without creating additional particle-particle forces in the cloud with a possibility

  10. Effect of bed temperature and bed composition on agglomeration during gasification of high-sodium, high-sulphur lignite in a spouted fluidised bed

    Energy Technology Data Exchange (ETDEWEB)

    D.P. McCullough; P.J. Mullinger; P.J. Ashman [University of Adelaide, Adelaide, SA (Australia). Cooperative Research Centre for Clean Power from Lignite, School of Chemical Engineering

    2003-07-01

    Fluidised bed gasification (FBG) is an alternative process for coal utilisation that delivers improved efficiencies and lower temperature operation compared to conventional technology. Agglomeration and defluidisation are phenomena that have the potential to occur within fluidised bed reactors, which can interrupt stable process operation. While extensive work has been carried out investigating fluidised bed combustion of lignite, relatively little work has been carried out for lignite under fluidised bed gasification conditions. Gasification of high sodium, high sulphur content lignite in a spouted bed gasifier (SBG) indicates that agglomeration and defluidisation is only an issue when maximum bed temperature exceeds approximately 850{degree}C and air/fuel ratios of 2.5 outside of these conditions, defluidisation is not detected. It is also demonstrated that defluidisation occurs before agglomeration, rather than as a result of agglomeration as previously thought. The Rosin-Rammler method of describing particle size distribution is found to yield appropriate variables for quantification of the extent of agglomeration taking place in cases where defluidisation is a factor. However, it has been shown by this method that while initial results indicated that agglomeration extent varies directly with maximum bed temperature, further results have shown that other variables, such as superficial velocity, have a significant impact on the extent of agglomeration. Investigations are currently continuing. 9 refs., 8 figs., 9 tabs.

  11. Activity of public employment services in the Poznan agglomeration for the benefit of the disabled persons

    Directory of Open Access Journals (Sweden)

    Robert Talaga

    2009-01-01

    Full Text Available In 2002-2007 public employment services enlarged the range of service offers within the frames of active policy of labour market for handicapped persons living in the city of Poznań and the poviat (commune. The attempt was successful despite permanent and not very high expenditure on solving the handicapped persons’ problems. Simultaneously there was an observable increase of expenditure on the whole active policy of Poznań agglomeration labour market. Owing to the law changes a lot of positive progress was achieved which introduced professional activation of handicapped people in the forms inaccessible to this group of citizens so far. It should be mentioned here that it came about also thanks to undertakings cofinanced with European funds, alongside with the assistance of private and non-governmental institutions. A constant ratio of the handicapped persons’ employment as well as slightly changeable number of handicapped persons registered at Poznań District Work Office, prove that the present situation does not develop in handicapped youth the necessary skills to actively search work, and it strengthens attitudes of professional passivity.

  12. On the thermal evolution of Pu-rich agglomerates in MOX

    International Nuclear Information System (INIS)

    From the experience accumulated so far on irradiated MOX fuel, its overall behaviour under irradiation is generally well predicted by existing fuel models. It appears however that additional data are still welcome to properly benchmark fission gas release models, mainly at elevated burnup. To this aim, an international research project, FIGARO, was initiated. Its goal was to provide thermal and fission gas release data og MOX at high burnup. Two MOX fuel rods irradiated to high burnup (50 GWd/tM peak pellet) but at lower power (less than 200 W/cm) were selected for segmentation and instrumentation with central thermocouple and pressure gauge. The instrumented segments were subjected to irradiations at variable linear power in the HALDEN MTR. Both temperature and internal pressure were online monitored during the ramp test. Afterwards, the rod segments were transported and extensively investigated. The paper focuses on the investigation of the evolution of the microstructure of Pu-rich agglomerates as a function of temperature

  13. Colorimetric and bare-eye determination of fluoride using gold nanoparticle agglomeration probes

    International Nuclear Information System (INIS)

    We report on a sensitive detection scheme for fluoride that is based on a quinone-methide-type of rearrangement reaction to trigger a color change among cloaked gold nanoparticle agglomeration probes. Fluoride ions remove silyl moieties from phenol groups on the surface of the probes, and this causes a quinone-methide-type of rearrangement reaction to occur. This is accompanied by the release of a dithiol in a spontaneous and irreversible reaction at room temperature in aqueous medium. The released dithiol causes aggregation of the AuNPs which leads to a color change from pink-red to violet-blue that can easily be seen with bare eyes.. The generation of color by this cascade reactions is only caused by fluoride and not interfered by any other anions. The assay platform developed here offers a sensitive colorimetric assay for fluoride. The lower limit of detection is 120 μM, and the dynamic concentration range is from 120 μM to 1.5 mM. (author)

  14. Workplace air measurements and likelihood of exposure to manufactured nano-objects, agglomerates, and aggregates

    Energy Technology Data Exchange (ETDEWEB)

    Brouwer, Derk H., E-mail: dick.brouwer@tno.nl; Duuren-Stuurman, Birgit van [TNO Research Group Risk Analysis for Products in Development (Netherlands); Berges, Markus [Institute für Arbeitsschutz - IFA (Germany); Bard, Delphine [Health and Safety Laboratory - HSL (United Kingdom); Jankowska, Elzbieta [Central Institute for Labour Protection - National Research Institute – CIOP-PIB (Poland); Moehlmann, Carsten; Pelzer, Johannes [Institute für Arbeitsschutz - IFA (Germany); Mark, Dave [Health and Safety Laboratory - HSL (United Kingdom)

    2013-11-15

    Manufactured nano-objects, agglomerates, and aggregates (NOAA) may have adverse effect on human health, but little is known about occupational risks since actual estimates of exposure are lacking. In a large-scale workplace air-monitoring campaign, 19 enterprises were visited and 120 potential exposure scenarios were measured. A multi-metric exposure assessment approach was followed and a decision logic was developed to afford analysis of all results in concert. The overall evaluation was classified by categories of likelihood of exposure. At task level about 53 % showed increased particle number or surface area concentration compared to “background” level, whereas 72 % of the TEM samples revealed an indication that NOAA were present in the workplace. For 54 out of the 120 task-based exposure scenarios, an overall evaluation could be made based on all parameters of the decision logic. For only 1 exposure scenario (approximately 2 %), the highest level of potential likelihood was assigned, whereas in total in 56 % of the exposure scenarios the overall evaluation revealed the lowest level of likelihood. However, for the remaining 42 % exposure to NOAA could not be excluded.

  15. Processing and Sintering of Agglomerate-free CaO-ZrO2 Powder

    Institute of Scientific and Technical Information of China (English)

    Liping LIANG; Shu'e DANG; Dong WU; Yuhan SUN

    2004-01-01

    Coprecipitation supercritical fluid drying technology has been employed to synthesize calcia-stabilized zirconia ultrafine powder with low-cost inorganic salts as the starting materials. The sintering behaviors of these powders were also investigated. The results showed that supercritical fluid drying could effectively alleviate the hard agglomeration of grains during the gel drying process, and the morphology of the powder retained the network texture of the original gel.The resulting particles were characterized by small particle size (5~20 nm), better monodispersity and high surface area, which gave rise to high activity and sinterability. Consequently, these powders could readily be compacted into the desired shape and their densification could be carried out in shorter time and at lower temperatures. For instance,nanometer-sized powder calcined at 600℃ for 2 h could be cold-pressed into a green body and sintered at 1100° for 0.5 h to attain a dense body with bulk density of 5.9718 g/cm3 and specific pore volume of 0.0008 cm3/g.

  16. Gold, silver, and palladium nanoparticle/nano-agglomerate generation, collection, and characterization

    International Nuclear Information System (INIS)

    Generation, collection, and characterization of gold, silver, and palladium nanoparticles and nano-agglomerates (collectively “nanoparticles”) have been explored. The nanoparticles were generated with a spark aerosol generator (Palas GFG-1000). They were collected using a deposition cell under diffusion and thermophoresis. The shapes and sizes of the deposited particles were measured using transmission electron microscopy (TEM). TEM images showed that the particles were in the range of 8–100 nm in diameter, and their shapes varied from nearly spherical to highly non-spherical. Thermophoresis enhanced the deposition of nanoparticles (over the diffusive or the isothermal deposition) in all cases. Further, the size distributions of the nanoparticles generated in the gas phase (aerosol) were measured using a scanning mobility particle sizer (SMPS 3080, TSI) spectrometer. The SMPS results show that an increase in the spark frequency of the generator shifted the size distributions of the nanoparticles to larger diameters, and the total particle mass production rate increased linearly with increase in the spark frequency. The computational fluid dynamics code Fluent (Ansys) was used to model the flow in the deposition cell, and the computed results conform to the observations.

  17. Workplace air measurements and likelihood of exposure to manufactured nano-objects, agglomerates, and aggregates

    International Nuclear Information System (INIS)

    Manufactured nano-objects, agglomerates, and aggregates (NOAA) may have adverse effect on human health, but little is known about occupational risks since actual estimates of exposure are lacking. In a large-scale workplace air-monitoring campaign, 19 enterprises were visited and 120 potential exposure scenarios were measured. A multi-metric exposure assessment approach was followed and a decision logic was developed to afford analysis of all results in concert. The overall evaluation was classified by categories of likelihood of exposure. At task level about 53 % showed increased particle number or surface area concentration compared to “background” level, whereas 72 % of the TEM samples revealed an indication that NOAA were present in the workplace. For 54 out of the 120 task-based exposure scenarios, an overall evaluation could be made based on all parameters of the decision logic. For only 1 exposure scenario (approximately 2 %), the highest level of potential likelihood was assigned, whereas in total in 56 % of the exposure scenarios the overall evaluation revealed the lowest level of likelihood. However, for the remaining 42 % exposure to NOAA could not be excluded

  18. A novel recovery technology of trace precious metals from waste water by combining agglomeration and adsorption

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A novel and efficient technology for separating and recovering precious metals from waste water containing traces of Pd and Ag was studied by the combination of agglomeration and adsorption. The recovery process and the impacts of operating conditions such as pH value of waste water, adsorption time, additive quantity of the flocculant and adsorbent on the recovery efficiency were studied experimentally. The results show that Freundlich isothermal equation is suitable for describing the behavior of the recovery process, and the apparent first-order adsorption rate constant k at 25 ℃ is about 0.233 4 h-1 The optimum technology conditions during the recovery process are that pH value is 8-9; the volume ratio of flocculant to waste water is about 1 :(2 000-4 000); the mass ratio of adsorbent to waste water is 1 :(30-40); and processing time is 2-4 h. Finally, the field tests were done at the optimum technology conditions, which show that the total concentration of Pd and Ag in the waste water below 11 mg/L can be reduced to be less than 1 mg/L.

  19. Urban agglomerations in the function of regional integration of Serbia in South-Eastern Europe

    Directory of Open Access Journals (Sweden)

    Tošić Dragutin

    2005-01-01

    Full Text Available In this article is analyzed the importance of urban agglomerations in the regional organization of Serbian space at one side, and on the other side they are taken as carriers of the future integration of the Serbian urban system into the urban of the South-Eastern Europe (SEE. In the regional configuration of Serbia, more different forms of territorial impacts of urbanization, urban areas and urban regions. High level of urban centralization is formed under the influence of the population density and functions of the metropolitan area of Belgrade. The problems of unbalanced disposition of population growth and qualitative transformation of urban centers are stressed and analyzed. Based on the role in integration process in the SEE, the metropolitan region of Belgrade is pointed out as its principal carrier and the metropolitan region of Niš as its secondary carrier, as well as the urban centers of importance for the cross-border regional cooperation. As the most suitable instrument of internal regional integration the model of Functional Urban Regions (FURs or Functional Urban Areas (FUAs is proposed, and for external regional integration is proposed the model of Metropolitan European Growth Areas (MEGAs. The coherent short-term and long-term development strategies for Serbian towns and their regions seem absent.

  20. Quality control of (Th,Pu)O2 fuel pellet obtained by coated agglomerate pelletization

    International Nuclear Information System (INIS)

    (Th,Pu)O2 fuel pellets were synthesised by coated agglomerate pelletization route and characterized for the chemical quality control. (Th,Pu)O2 pellets were characterized for trace metals by spectrometric methods and non metals by ion chromatographic, spectrophotometric, conductometric and manometric methods. H, F, B and Cd contents were found to be less than 1 ppm while that for V and Cl were found to be less than 10 ppm. The pellets were found to contain Cr, Cu, Mo, Na, Ni and Pb in the range of 10-50 ppm whereas Zn, Al, Ca and C in the range of 50-100 ppm. More than 100 ppm Si, Fe and Mg were found to be present in the (Th,Pu)O2 pellets. The O/M content of the pellets were found to be ∼2.00. A comparative study on (Infrared) I.R. and microwave (microwave) dissolution were also used to ascertain the Th and Pu content in the (Th,Pu)O2 pellets. (author)

  1. Measurement and Spatial Distribution of Urban Agglomeration Industrial Compactness in China

    Institute of Scientific and Technical Information of China (English)

    QI Weifeng; FANG Chuanglin; SONG Jitao

    2008-01-01

    Urban agglomeration (UA) compactness means spatial concentration degree of physical entities, such as cities (towns), industries, resources, funds, traffic and technologies, whose concentration is formed according to speci-fied economic and technologic association in the process of UA formation and development. The UA industrial com-pactness means the concentration degree of industry and industry clusters with reference to the industrial, technologi-cal and economic relations among the cities in the UA in the process of rational industrial division and with the exten-sion of industrial chain. After analyzing the researches on compactness, this paper finds that the relevant measurement coefficient and methods reflecting industrial geographical concentration fail to link industries spatial concentration with urban spatial concentration. Taking 23 UAs as samples and classifying them by development degree, this paper probes into UA compactness and spatial distribution characteristics from the perspective of industry by adopting UA index systems of industry and measurement models. The research finds out: 1) there is obvious positive correlation between UA industrial compactness and UA development degree; 2) the spatial distribution difference of UA industrial compactness is relatively great; and 3) UA industrial compactness shows a gradually decreasing tendency from the eastern part, the middle part to the western part of China. From the research thoughts and approaches, this article sug-gests that studies on the UA integrated compactness measurement should be enhanced from a multidimensional per-spective involving space, traffic, population density and so on.

  2. Morphological characterization with image analysis of cocoa beverage powder agglomerated with steam

    Directory of Open Access Journals (Sweden)

    Fernanda Zaratini Vissotto

    2014-12-01

    Full Text Available In this study, the morphological characteristics of cocoa beverage powder granules under minimal, average, and maximal process conditions of a steam agglomerator were studied. a stereoscopic microscope coupled to a digital camera was used for the morphological analysis. The images were analyzed to obtain shape and size descriptors. aiming to evaluate the descriptors, 150 particles were analyzed. The results showed that there was no difference between the shape descriptors - compacity, circularity, roughness, and aspect ratio - in the operating conditions evaluated. It was observed that the cocoa beverage powder granules are elongated in shape. The size descriptors, area, perimeter, perimeter of convex bounding polygon, minimal and maximal Feret diameter, were different in the process conditions for the granules of size above 600 μm. as for the minimal process conditions, especially due to low solid feed rates, there is an increase in the size descriptor values. In addition, under the minimum process conditions, in which there is low solid feed rate (400g/min for a steam pressure of 1.0 bar, it was obtained a good granular condition with retention of 81.1% of granules on sieves with aperture size between 300 and 1190 μm.

  3. Impact Of Particle Agglomeration On Accumulation Rates In The Glass Discharge Riser Of HLW Melter

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, A. A. [Department of Energy, Office of River Protection, Richland, WA (United States); Rodriguez, C. A. [Pacific Northwest National Laboratory, Richland, WA (United States); Matyas, J. [Pacific Northwest National Laboratory, Richland, WA (United States); Owen, A. T. [Pacific Northwest National Laboratory, Richland, WA (United States); Jansik, D. P. [Pacific Northwest National Laboratory, Richland, WA (United States); Lang, J. B. [Pacific Northwest National Laboratory, Richland, WA (United States)

    2012-11-12

    The major factor limiting waste loading in continuous high-level radioactive waste (HLW) melters is an accumulation of particles in the glass discharge riser during a frequent and periodic idling of more than 20 days. An excessive accumulation can produce robust layers a few centimeters thick, which may clog the riser, preventing molten glass from being poured into canisters. Since the accumulation rate is driven by the size of particles we investigated with x-ray microtomography, scanning electron microscopy, and image analysis the impact of spinel forming components, noble metals, and alumina on the size, concentration, and spatial distribution of particles, and on the accumulation rate. Increased concentrations of Fe and Ni in the baseline glass resulted in the formation of large agglomerates that grew over the time to an average size of ~185+-155 {mu}m, and produced >3 mm thick layer after 120 h at 850 deg C. The noble metals decreased the particle size, and therefore significantly slowed down the accumulation rate. Addition of alumina resulted in the formation of a network of spinel dendrites which prevented accumulation of particles into compact layers.

  4. A protosolar nebula origin for the ices agglomerated by Comet 67P/Churyumov-Gerasimenko

    CERN Document Server

    Mousis, O; Luspay-Kuti, A; Guillot, T; Marty, B; Ali-Dib, M; Wurz, P; Altwegg, K; Bieler, A; Hässig, M; Rubin, M; Vernazza, P; Waite, J H

    2016-01-01

    The nature of the icy material accreted by comets during their formation in the outer regions of the protosolar nebula is a major open question in planetary science. Some scenarios of comet formation predict that these bodies agglomerated from crystalline ices condensed in the protosolar nebula. Concurrently, alternative scenarios suggest that comets accreted amorphous ice originating from the interstellar cloud or from the very distant regions of the protosolar nebula. On the basis of existing laboratory and modeling data, we find that the N$_2$/CO and Ar/CO ratios measured in the coma of the Jupiter family comet 67P/Churyumov-Gerasimenko by the ROSINA instrument aboard the European Space Agency's Rosetta spacecraft match those predicted for gases trapped in clathrates. If these measurements are representative of the bulk N$_2$/CO and Ar/CO ratios in 67P/Churyumov-Gerasimenko, it implies that the ices accreted by the comet formed in the nebula and do not originate from the interstellar medium, supporting the...

  5. Analysis on the formation condition of the algae-induced odorous black water agglomerate.

    Science.gov (United States)

    Wang, Guofang; Li, Xianning; Fang, Yang; Huang, Rui

    2014-12-01

    The algae-induced odorous black water agglomerate (OBWA) is a phenomenon in which water turns black and emits odorous gas. It is an ecological and environmental problem that has occurred several times in Taihu, a large eutrophic shallow lake in China. In this study, the collected eutrophic water with different algae densities was used to simulate OBWA. The results revealed that the massive accumulation and death of algae was the substrate source for OBWA. When the algae density reached 1.0 × 10(8) cells/L in the static and dark condition, at a constant high temperature (30 ± 2 °C), OBWA happened. There was a time difference between the water stinking and blackening with the stinking first. When the oxidation-reduction potential (ORP) value was between -250 and -50 mV, Dimethyl trisulfide (DMTS), the main contributor to the water stinking at the initial stage, and other odorous organics were produced. Water blackening was closely related to the increases of sulfide and dissolved Fe(2+) concentration. When the ORP value was between -350 and -300 mV, heavy metal containing sulfides such as FeS formed. Therefore, the condition when the water ORP value decreased to about -300 mV was considered the precursor for OBWA formation. PMID:25473369

  6. Influence of Membrane Thickness on Membrane Degradation and Platinum Agglomeration under Long-term Open Circuit Voltage Conditions

    International Nuclear Information System (INIS)

    Highlights: • The degradation of three composite membranes with various thicknesses under OCV was investigated. • A high hydrogen crossover would accelerate the thinning of the composite membranes. • Pt particle growth can be enhanced due to the hot point generated by permeable hydrogen and oxygen. - Abstract: Membrane chemical degradation and platinum catalyst agglomeration under long-term open circuit voltage (OCV) conditions were investigated using three types of composite membranes with various membrane thicknesses. Hydrogen permeation increases as membrane thickness decreases, which has a significant influence on proton exchange membrane and platinum catalysts. Higher Hydrogen permeation accelerated the membrane degradation, resulting in the thinning of membrane which can be verified by fluoride emission rates (FERs). Carbon-supported platinum catalysts also experienced agglomeration under OCV conditions. The statistics of platinum size distribution demonstrated catalysts size growth, ranging from 3.83 to 6.02 nm in diameter along with the increasing hydrogen crossover

  7. The neglected heterogeneity of spatial agglomeration and co-location patterns of creative employment: evidence from Portugal

    OpenAIRE

    Sara Santos Cruz; Aurora A.C. Teixeira

    2013-01-01

    Empirical literature on the geographic location of creative activities is mostly based on the spatial analysis of industries, disregarding the creative employment that lies outside the necessarily limited boundaries of creative industries. In this paper, we analyse agglomeration and co-location patterns of core creative activities by considering both ‘embedded’ (creative professionals working outside the creative sectors) and ‘specialized’ (creative professionals working in the creative secto...

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

    Energy Technology Data Exchange (ETDEWEB)

    Vuthaluru, H.B.; Linjewile, T.M.; Zhang, D.; Manzoori, A.R. [University of Adelaide, Adelaide, SA (Australia). Dept. of Chemical Engineering

    1999-03-01

    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 bed combustion of low-rank coals. The three control techniques investigated are: (1) the use of mineral additives; (2) alternative bed materials; and (3) pretreatment of coal. Mineral additives including dolomite, two clays and gibbsite, were injected into the spouted bed combustor while burning a South Australian low-rank coal at 800{degree}C. Samples of the same coal treated with Al, water washing and acid washing were also tested in the spouted bed combustor. In addition, experiments were also conducted with alternative bed materials including bauxite and calcined sillimanite. Experiments showed that the three techniques reported in this paper are effective to different extents in reducing particle agglomeration and defluidisation. Among the mineral additives tested, gibbsite and a clay additive rich in kaolinite and sillimanite were found to be most effective. The use of calcined sillimanite and bauxite as alterative bed materials extended the combustion time before defluidisation occurred by 7 and 10 times, respectively, compared to silica sand. While A1 pretreatment and water-washing were found effective for control of agglomeration and defluidisation, acid-washing did not improve the operation of the bed burning this particular coal. Al enrichment in ash coating of bed particles which suppress the formation of Na and S rich eutectics was identified as the main mechanism for prevention of agglomeration and defluidisation by these control techniques. 10 refs., 4 figs., 3 tabs.

  9. Current Trends Of The Regional Development Policy In The European Union. The Development Of Competitive Economic Agglomerations Of Cluster Type

    OpenAIRE

    LAURA CISMAŞ; ANDRA MICULESCU; MARIA OŢIL

    2010-01-01

    The study of economic agents’ behaviour, whose nowadays tendency is to group themselves in space as clusters, has an important place in the field of localizing industrial activities. This is due to domestic scale economies, known as agglomerations economies. According to Edgar M. Hoover (Hoover, 1948), domestic scale economies are specific to companies; the economies of localizing - to a certain branch, whose companies form clusters in certain geographical arias, and the urbanization economie...

  10. Experimental evaluation of acoustic agglomerators as an air cleaning system concept for emergency use in LMFBR plants. Final report

    International Nuclear Information System (INIS)

    In the development of the Liquid Metal Fast Breeder Reactor, a major safety problem concerns the suppression of the sodium oxides aerosol particles produced during a hypothetical core disruptive accident. Some theoretical calculations are presented concerning sonic agglomeration rates of such a system in terms of acoustic frequency, intensity and particles. The information is useful in providing some guidelines for the evaluation and design of sonic systems for LMFBR emergency applications

  11. Intensity of Spherical Agglomerated Boron Particles%球形团聚硼颗粒的强度研究

    Institute of Scientific and Technical Information of China (English)

    庞维强; 樊学忠; 胥会祥; 李勇宏

    2009-01-01

    The amorphous boron powders were agglomerated to high-intensity spherical particles by means of mechanical mixing with hydroxyl terminated polybutadiene as raw materials and with acetic ether as solvent. The factors affecting the intensity of particles during the agglomerated process were analyzed. The optimal process conditions were obtained: the rotation speed is 90 r · min~(-1); the agglomerated process temperature is 30 ℃ ; the mass ratio of binder and amorphous boron powder is 10/90 and the mass content of solidification catalyst is 0. 02% ; the morphological structure of agglomerated boron particles prepared by the method is preferable and the intensity of particles is higher.%以端羟基聚丁二烯(HTPB)为原材料,乙酸乙酯为溶剂,采用机械搅拌方法对无定形硼粉进行团聚改性处理,对球形团聚硼颗粒制备过程中不同工艺条件下的颗粒强度的影响因素进行了研究,获得了强度较高的球形团聚硼颗粒,最佳工艺条件为: 搅拌速度为90 r·min~(-1),团聚工艺温度为30 ℃,黏结剂与硼粉的质量配比为10/90,固化催化剂的质量含量为0.02%,在此工艺条件下制备出的团聚硼颗粒形貌较好,颗粒强度较高.

  12. The Land Management Pattern in " Green Heart" Area——A Case Study of Changsha-Zhuzhou-Xiangtan Urban Agglomeration

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    By analyzing the status quo of land resources in " green heart" area of Changsha-Zhuzhou-Xiangtan urban agglomeration,and problems existing in land management,this article puts forward some countermeasures and proposals as follows:establish new land management mechanism in " green heart" area;based on land planning," green heart" overall planning and policies and regulations,manage land and promote the protection of urban ecological environment.

  13. A two-phase flow and non-isothermal agglomerate model for a proton exchange membrane (PEM) fuel cell

    International Nuclear Information System (INIS)

    A two dimensional, across the channel, steady-state model for a proton exchange membrane fuel cell (PEMFC) is presented in which the non-isothermal model for temperature distribution, the two-phase flow model for liquid water transport and the agglomerate model for oxygen reduction reaction are fully coupled. This model is used to investigate thermal transport within the membrane electrode assembly (MEA) associated with the combinational water phase-transfer and transport mechanisms. Effective temperature distribution strategies are established aim to enhance the cell performance. Agglomerate assumption is adopted in which the ionomer and liquid water in turn cover the agglomerate to form the ionomer and liquid water films. Ionomer swelling is associated with the non-uniform distribution of the water content. The modelling results show that heat accumulates within the cathode catalyst layer under the channel. Higher operating temperature improves the cell performance by increasing the kinetics, reducing the liquid water saturation on the cathode and increasing the water carrying capacity of the anode gas. Applying higher temperature on the anode and enlarging the width ratio of the channel/rib could improve the cell performance. Higher cathode temperature decreases the oxygen mole fraction, resulting in an insufficient oxygen supply and a limitation of the cell performance. - Highlights: • The two-phase flow and non-isothermal model couple with the agglomerate model. • Oxygen diffusivity and solubility in Nafion® relate to water content and temperature. • Higher anode operating temperature improves the fuel cell performance. • Insufficient oxygen supply limits cell performance at higher current densities

  14. Analysis of bed agglomeration during gasification of wheat straw in a bubbling fluidised bed gasifier using mullite as bed material

    OpenAIRE

    Mac an Bhaird, Seán T.; Walsh, Eilín; Hemmingway, Phil; McDonnell, Kevin; et al.

    2014-01-01

    The quantity and composition of the ash content of straw poses technical challenges to its thermal conversion and have been widely reported to cause severe ash sintering and bed agglomeration during fluidised bed gasification. Literature indicates that a combination of reactor design and bed material measures is required to avoid defluidisation at temperatures above 800 °C. Using scanning electron microscopy and energy dispersive X-ray spectroscopy this study investigated the initial agglomer...

  15. Effect of Electromagnetic Vibration on the Agglomeration Behavior of Primary Silicon in Hypereutectic Al-Si Alloy

    Science.gov (United States)

    Han, Yecong; Li, Qiulin; Liu, Wei; He, Yanjie

    2012-05-01

    An experimental apparatus that enables the simultaneous application of an alternating electric field and a stationary magnetic field was developed. Electromagnetic vibration was induced in a hypereutectic Al-Si alloy melt during solidification at a constant cooling rate. The results showed that the silicon particles collide with each other and agglomerate into clusters with the application of an electromagnetic vibration. With the increase of the electromagnetic force F, the sizes of the silicon clusters decrease and the clusters become more compact.

  16. Study on GIS Visualization in Evaluation of the Human Living Environment in Shenyang-Dalian Urban Agglomeration.

    Science.gov (United States)

    Hou, Kang; Zhou, Jieting; Li, Xuxiang; Ge, Shengbin

    2016-01-01

    Analysis of human living environmental quality of Shenyang-Dalian urban agglomerations has important theoretical and practical significance in rapid development region. A lot of investigations have been carried for Shenyang-Dalian urban agglomerations, including 38 counties. Based on the carrying capacity of resources, natural and socioeconomic environmental factors and regional changes of human living environmental evaluation are analyzed with the application of geographic information systems (GIS) software. By using principal component analysis (PCA) model and natural breaks classification (NBC) method, the evaluation results are divided into five categories. The results show that the human living environmental evaluation (HLEE) indexes of Dalian, Shenyang, and Liaoyang are higher than other counties. Among these counties, the human living environmental evaluation (HLEE) indexes of coastal counties are significantly higher than inland counties. The range of the human living environmental evaluation index in most of the study area is at III, IV, and V levels, accounting for 80.01%. Based on these results, it could illustrate the human living environment is in relatively suitable condition in Shenyang-Dalian urban agglomeration. PMID:27200212

  17. IMPACT OF PARTICLE SIZE AND AGGLOMERATION ON SETTLING OF SOLIDS IN CONTINUOUS MELTERS PROCESSING RADIOACTIVE WASTE GLASS

    Energy Technology Data Exchange (ETDEWEB)

    HRMA PR

    2008-12-18

    The major factor limiting waste loading for many waste compositions in continuous waste glass melters is the settling of crystalline materials. The currently used constraints, i.e., the minimum liquidus temperature or the maximum fraction of equilibrium crystallinity at a given temperature, are based on thennodynamic equilibria. Because of the rapid circular convection in the melter, these constraints are probably irrelevant and cannot prevent large crystals from settling. The main factor that detennines the rate of settling ofindividual crystals, such as those ofspinel, is their size. The tiny crystals of RU02 are too small to settle, but they readily fonn large agglomerates that accelerate their rate ofsettling by severalorders ofmagnitude. The RU02 agglomerates originate early in the melting process and then grow by the shear-flocculation mechanism. It is estimated that these agglomerates must either be ofhundreds micrometers in size or have an elongated shape to match the observed rates ofthe sludge-layer fonnation. PACS: 47.57.ef, 81.05.Kj, 81.10.Fg

  18. Study on GIS Visualization in Evaluation of the Human Living Environment in Shenyang-Dalian Urban Agglomeration

    Science.gov (United States)

    Hou, Kang; Zhou, Jieting; Li, Xuxiang; Ge, Shengbin

    2016-01-01

    Analysis of human living environmental quality of Shenyang-Dalian urban agglomerations has important theoretical and practical significance in rapid development region. A lot of investigations have been carried for Shenyang-Dalian urban agglomerations, including 38 counties. Based on the carrying capacity of resources, natural and socioeconomic environmental factors and regional changes of human living environmental evaluation are analyzed with the application of geographic information systems (GIS) software. By using principal component analysis (PCA) model and natural breaks classification (NBC) method, the evaluation results are divided into five categories. The results show that the human living environmental evaluation (HLEE) indexes of Dalian, Shenyang, and Liaoyang are higher than other counties. Among these counties, the human living environmental evaluation (HLEE) indexes of coastal counties are significantly higher than inland counties. The range of the human living environmental evaluation index in most of the study area is at III, IV, and V levels, accounting for 80.01%. Based on these results, it could illustrate the human living environment is in relatively suitable condition in Shenyang-Dalian urban agglomeration. PMID:27200212

  19. Assessment of silver nanoparticle toxicity for common carp (Cyprinus carpio) fish embryos using a novel method controlling the agglomeration in the aquatic media

    Czech Academy of Sciences Publication Activity Database

    Opršal, J.; Bláha, L.; Pouzar, M.; Knotek, P.; Vlček, Milan; Hrdá, K.

    2015-01-01

    Roč. 22, č. 23 (2015), s. 19124-19132. ISSN 0944-1344 Institutional support: RVO:61389013 Keywords : nanosilver * agglomeration * fish embryo Subject RIV: DJ - Water Pollution ; Quality Impact factor: 2.828, year: 2014

  20. Impact of alginate concentration on the stability of agglomerates made of TiO2 engineered nanoparticles: Water hardness and pH effects

    International Nuclear Information System (INIS)

    The stability of engineered nanoparticles in natural aquatic systems is of high interest for environmental risk assessment since an already important quantity of these reactive species is entering aquatic systems. In the present study, an important issue is addressed by investigating (i) the influence of divalent cations and water hardness (Mg2+ and Ca2+) in agglomerate formation and (ii) alginate concentration effect on the stability TiO2 agglomerates formed in environmental freshwater conditions (pH and total hardness) representative of Lake Geneva, France/Switzerland. Our results indicate that the presence of alginate at typical natural organic matter concentration strongly modifies the stability of TiO2 nanoparticle agglomerates by inducing their partial disagglomeration. Significant TiO2 nanoparticles redispersion and formation of small fragments are expected to be induced by alginate adsorbed layer formed at the nanoparticle surfaces within the agglomerates.Graphical Abstract

  1. Application of synchrotron radiation X-ray computed tomography to investigate the agglomerating behavior of TiB2 particles in aluminum

    International Nuclear Information System (INIS)

    Highlights: • SR-CT was a powerful tool to investigate the TiB2 distribution in Al-TiB2 in situ composites. • Three kinds of agglomerations frequently present in the composites. • Agglomerations formed via the diffused atoms reacting with intermediate products. • The composites containing agglomerations show a much reduced ductility. - Abstract: Agglomeration of reinforcing particles has a number of deleterious effects on the properties of in situ metal matrix composites (MMCs). In order to better understand this phenomenon, the agglomerating behavior of TiB2 particles in aluminum based in situ MMCs was investigated using synchrotron radiation X-ray computed tomography (SR-CT) and field emission scanning electron microscope (FESEM). SR-CT was shown to be a powerful tool for visualizing and quantifying the three-dimensional (3D) features within the composites. Based on the SR-CT and FESEM results, a formation mechanism of the flaky agglomerates, flocculent agglomerates and clusters of coarse TiB2 particles, which are most frequently presented in the in situ Al/TiB2 composite, has been proposed. The mechanism shows that the formation of these three kinds of agglomerates can be attributed to three parallel processes, i.e. diffusing titanium atoms reacting with AlB2, aluminum melt directly reacting with emulsified salt, diffusing boron atoms reacting with TiAl3, respectively. Moreover, the mechanism may shed some light on how to design better processing techniques for obtaining homogenous particle distribution in in situ Al/TiB2 composites in the future

  2. 3D RVE Models Able to Capture and Quantify the Dispersion, Agglomeration, and Orientation State of CNT in CNT/PP Nanocomposites

    OpenAIRE

    Md A. Bhuiyan; Pucha, Raghuram V.; Kalaitzidou, Kyriaki

    2016-01-01

    The focus of this study is to investigate the capabilities of three dimensional (3D) RVE models in predicting the tensile modulus of carbon nanotube/polypropylene (CNT/PP) composites, which differ slightly in the dispersion, agglomeration, and orientation states of CNT within the PP matrix. The composites are made using melt mixing followed by either injection molding or melt spinning of fibers. The dispersion, agglomeration, and orientation of CNT within the PP are experimentally altered by ...

  3. Agglomeration and size distribution of debris in DEFOR-A experiments with Bi2O3–WO3 corium simulant melt

    International Nuclear Information System (INIS)

    Highlights: • Debris agglomeration in case of melt pouring into a coolant is experimentally investigated. • The effects of jet diameter, melt superheat and water subcooling are addressed. • Most influential factor which can significantly increase fraction of agglomerates is melt superheat. • Rapid decrease of the fraction of agglomerates as a function of water depth is obtained in all cases. • Provided data is valuable for model development and code validation. -- Abstract: Flooding of lower drywell has been adopted as a cornerstone of severe accident management strategy in Nordic type Boiling Water Reactors (BWR). It is assumed that the melt ejected into a deep pool of water will fragment, quench and form a porous debris bed coolable by natural circulation. If debris bed is not coolable, then dryout and possibly re-melting of the debris can occur. Melt attack on the containment basemat can threaten containment integrity. Agglomeration of melt debris and formation of solid “cake” regions provide a negative impact on coolability of the porous debris bed. In this work we present results of experimental investigation on the fraction of agglomerated debris obtained in the process of hot binary oxidic melt pouring into a pool of water. The Debris Bed Formation and Agglomeration (DEFOR-A) experiments provide data about the effects of the pool depth and water subcooling, melt jet diameter, and initial melt superheat on the fraction of agglomerated debris. The data presents first systematic study of the debris agglomeration phenomena and facilitates understanding of underlying physics which is necessary for development and validation of computational codes to enable prediction of the debris bed coolability in different scenarios of melt release

  4. Agglomeration and size distribution of debris in DEFOR-A experiments with Bi{sub 2}O{sub 3}–WO{sub 3} corium simulant melt

    Energy Technology Data Exchange (ETDEWEB)

    Kudinov, Pavel, E-mail: pavel@safety.sci.kth.se; Karbojian, Aram, E-mail: aram@safety.sci.kth.se; Tran, Chi-Thanh, E-mail: thanh@safety.sci.kth.se; Villanueva, Walter, E-mail: walter@safety.sci.kth.se

    2013-10-15

    Highlights: • Debris agglomeration in case of melt pouring into a coolant is experimentally investigated. • The effects of jet diameter, melt superheat and water subcooling are addressed. • Most influential factor which can significantly increase fraction of agglomerates is melt superheat. • Rapid decrease of the fraction of agglomerates as a function of water depth is obtained in all cases. • Provided data is valuable for model development and code validation. -- Abstract: Flooding of lower drywell has been adopted as a cornerstone of severe accident management strategy in Nordic type Boiling Water Reactors (BWR). It is assumed that the melt ejected into a deep pool of water will fragment, quench and form a porous debris bed coolable by natural circulation. If debris bed is not coolable, then dryout and possibly re-melting of the debris can occur. Melt attack on the containment basemat can threaten containment integrity. Agglomeration of melt debris and formation of solid “cake” regions provide a negative impact on coolability of the porous debris bed. In this work we present results of experimental investigation on the fraction of agglomerated debris obtained in the process of hot binary oxidic melt pouring into a pool of water. The Debris Bed Formation and Agglomeration (DEFOR-A) experiments provide data about the effects of the pool depth and water subcooling, melt jet diameter, and initial melt superheat on the fraction of agglomerated debris. The data presents first systematic study of the debris agglomeration phenomena and facilitates understanding of underlying physics which is necessary for development and validation of computational codes to enable prediction of the debris bed coolability in different scenarios of melt release.

  5. Effect of Agglomeration on Combustion of Metallized Propellants for Air-Breathing Propulsion System.

    Directory of Open Access Journals (Sweden)

    R. Bhaskara Rao

    1996-12-01

    Full Text Available Combustion phenomena of metallized propellants containing the metals viz. Mg, Zr, Al and B with NaND3 as oxidizer have been studied in order to find out burning rate variations at different oxidizer levels and at different particle sizes of the ingredients. It is found that the burning rate of Mg-NaND3 and Zr-NaND3 compositions with finer size NaND3 shows higher values at lower oxidizer content and decreases with increasing concentration of the oxidizer. In contrast AI-NaND3 and B-NaND3 formulations show continuous increase in burning rate with the increase in oxidizer content. Further, the burning rate of all the formulations with NaND3 of coarser size is found to increase on increasing the oxidizer content. Thermal decomposition results indicate that in the case of Mg and Zr formulations, decomposition products of finer size NaND3 formed before reacting to ignition temperature of the metal, react with the metal particles leading to condensed phase heat release causing higher burning rate. An increase of oxidizer content leads to a thicker oxide coating on the metal particles resulting in the formation of metal agglomerates which burn inefficiently in the vapour phase causing lower burning rate. With coarser size NaND3, due to its decomposition occurring beyond the ignition temperature of the metal particles, reactions shift to the vapour phase diffusion zone causing increase in the burning rate as the concentration of NaND3 increases. Combustion of Al and B particles with NaND3 occurs beyond the melting/ignition temperatureof the metal at all the concentrations and particle sizes of oxidizer, causing increase of burningrate with increasing oxidizer content.

  6. A Protosolar Nebula Origin for the Ices Agglomerated by Comet 67P/Churyumov-Gerasimenko

    Science.gov (United States)

    Mousis, O.; Lunine, J. I.; Luspay-Kuti, A.; Guillot, T.; Marty, B.; Ali-Dib, M.; Wurz, P.; Altwegg, K.; Bieler, A.; Hässig, M.; Rubin, M.; Vernazza, P.; Waite, J. H.

    2016-03-01

    The nature of the icy material accreted by comets during their formation in the outer regions of the protosolar nebula (PSN) is a major open question in planetary science. Some scenarios of comet formation predict that these bodies agglomerated from crystalline ices condensed in the PSN. Concurrently, alternative scenarios suggest that comets accreted amorphous ice originating from the interstellar cloud or from the very distant regions of the PSN. On the basis of existing laboratory and modeling data, we find that the N2/CO and Ar/CO ratios measured in the coma of the Jupiter-family comet 67P/Churyumov-Gerasimenko by the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis instrument on board the European Space Agency’s Rosetta spacecraft match those predicted for gases trapped in clathrates. If these measurements are representative of the bulk N2/CO and Ar/CO ratios in 67P/Churyumov-Gerasimenko, it implies that the ices accreted by the comet formed in the nebula and do not originate from the interstellar medium, supporting the idea that the building blocks of outer solar system bodies have been formed from clathrates and possibly from pure crystalline ices. Moreover, because 67P/Churyumov-Gerasimenko is impoverished in Ar and N2, the volatile enrichments observed in Jupiter’s atmosphere cannot be explained solely via the accretion of building blocks with similar compositions and require an additional delivery source. A potential source may be the accretion of gas from the nebula that has been progressively enriched in heavy elements due to photoevaporation.

  7. Climatic effects of urban expansion over the three largest urban agglomerations of China

    Science.gov (United States)

    Cao, Qian; Yu, Deyong; Georgescu, Matei; Wu, Jianguo

    2016-04-01

    Urbanization has long been known to affect local, regional, and global climate. China is urbanizing at an unprecedented rate, and modification of land surface to urban areas has raised climate concerns for its citizens. Using the Weather Research and Forecasting (WRF) model, we examine how urbanization under different intensities and climate regimes affects regional climate of the three largest urban agglomerations across China - the Beijing-Tianjin-Hebei (BTH), the Yangtze River Delta (YRD), and the Pearl River Delta (PRD). We simulated three urban expansion scenarios corresponding to 1988, 2000, and 2010 conditions into the WRF model, with each scenario simulated by three separate summers (i.e., 2001, 2003, and 2005). Urban extent of the three regions indicates stable growth during 1988 - 2000, followed by a phase of rapid expansion during 2000 - 2010. Our simulations show that urban environment-induced near-surface warming, mainly rising temperatures during nighttime, is greatest over the BTH with local maximum warming approaching 1.5 °C, followed by the YRD with peak warming reaching 1 °C and the PRD 0.8 °C. Due to the initial moisture conditions, the YRD and the PRD suffer more humidity deficit, particularly during daytime, with maximum reductions in water vapor mixing ratio reaching 0.8 g/kg. Our findings demonstrate that urban expansion has warmed and dried the urbanized regions in eastern China. The spatial pattern and magnitude of temperature and humidity differences quantified by our simulations provide useful information for understanding the impacts of urbanization on regional climate and for developing mitigation and adaptation strategies that can alleviate the deleterious impacts induced by urban expansion.

  8. Effects of Slurry Chemistry on the Rate of Agglomeration of Alumina Nanoparticles for Chemical Mechanical Planarization

    Science.gov (United States)

    Brahma, Neil Anjan

    Chemical mechanical planarization (CMP) is a polishing process used during the manufacture of microelectronic integrated circuits. During fabrication of multilevel circuitry, excess deposited material must be removed and the wafer surface globally planarized for proper function of devices. This is especially necessary with copper interconnects, thus, copper CMP was the focus of this study. CMP requires the use of a slurry containing nanometer-sized abrasive particles along with a variety of chemical additives. The particles and chemicals act synergistically to mechanically and chemically remove material and provide a near globally planar surface. For optimal CMP performance, the effective abrasive particle size must be controlled. If particles aggregate, CMP performance may diminish and possibly even cause defective devices. The chemistry of the slurry (pH, ions present, etc) can not only affect the mean aggregate size of the abrasive particles, but also growth of aggregate over time. This research investigated the aggregation behavior of suspensions of 150 nm alumina particles in 1mM KNO3 with various additives (glycine, H2O2, benzotriazole, and sodium dodecyl sulfate) used in CMP of copper through effective particle (agglomerate) size versus time and zeta potential measurements. Aggregate size rate data were analyzed to elucidate the mechanism of aggregation, as well its effect on the structure of the resultant aggregate. The effects of temperature of the slurry were also explored. Finally, particle size distribution data collected at various stages of aggregation were incorporated into the Luo and Dornfeld model of CMP to investigate the dynamic nature of the CMP process.

  9. Current Trends in wastewater treatment in small agglomerations; Tendencias actuales en las tecnologias de tratamiento de las aguas residuales generadas en las pequenas aglomeraciones urbanas

    Energy Technology Data Exchange (ETDEWEB)

    Ferrer Medina, Y.; Ortega de Miguel, E.; Salas Rodriguez, J. J.

    2012-07-01

    Spain has a great number of small agglomerations. In fact from the 8.111 existing municipalities, 72% have less than 2.000 inhabitants and 47% of them (3.800) have less than 500 inhabitants. Concerning wastewater treatment in small agglomerations three periods can be distinguished. Before the 80{sup t}h, wastewater treatment plants were merely small reproductions of those applied in bigger agglomerations, and Extended Aeration was basically the only process. Due to their high energy and technical requirements, many of these small plants were left out of service. Extensive technologies appeared in Spain during the 80{sup t}h. Results were not as good as expected mainly due to design and construction failures. Nowadays, we are just starting to be aware that wastewater treatment in small agglomerations, need a new approach, more demanding concerning technical and management issues, to give an owner's to the origin of previous mistakes. This new approach offers a wide range of possible technologies (extensive, and mixed) each of them could be a good option depending on the specific characteristics of the agglomeration, and the discharge requirements. These paper reviews current trends concerning urban wastewater treatment is mall agglomerations, including consolidated technologies, emerging technologies and technologies which are still in development or in an experimental phase. (Author)

  10. Impregnation/Agglomeration Laboratory Tests of Heavy Fuel from Prestige to Improve Its Manageability and Removal from Seawater Surface. (Physical Behaviour of Fuel Agglomates)

    International Nuclear Information System (INIS)

    The handling and removal problems showed by heavy fuel floating in seawater could be improved or solved by using materials that agglomerate it. These materials must fulfill the following conditions: be inert materials in marine environment, the agglomerated fuel/material should float and its application and removal should be done using simple technologies. Based on these requirements, clay minerals, pine chips, mineral coal and charcoal were selected. The preliminary/results on impregnation/agglomeration with the materials mentioned above of heavy fuel from Prestige at lab scale are presented in this paper. The results have shown that only hydrophobic materials, such as mineral coal and charcoal, are able to agglomerate with fuel, which is also a hydrophobic substance. Whereas the agglomerates fuel/mineral coal sink, the agglomerates fuel/charcoal keep floating on water surface. It can be concluded that the addition of charcoal on dispersed fuel in seawater could improve its handling and removal. In this sense, pilot scale and eventually controlled in situ tests to study the feasibility of the proposed solution should be performed. (Author) 2 refs

  11. 河南省产业集聚区空间规划引导研究%Industrial Agglomeration Area Spatial Planning Guide Research of Henan Province

    Institute of Scientific and Technical Information of China (English)

    黄向球; 高耸; 麻永建; 牛艳华

    2014-01-01

    河南省产业集聚区作为推动区域城镇化进程和产业结构升级转型的重要动力,其发展建设深刻影响着河南省区域人口的集聚及城镇化进程。产业集聚区空间规划是促进产业集聚区有序发展的前提,通过对河南省产业集聚区前期规划进行深入研究,找出目前产业集聚区空间规划存在的问题,提出“五规合一”和“产城融合”的规划理念,以此为基础,在产业引导、空间统筹引导和政策措施引导3个层面破解产业集聚区空间规划存在的问题,同时为产业集聚区空间规划提供方法与策略的引导,促进产业集聚区与城市的深度融合,保证产业集聚区的健康发展。%Henan industrial agglomeration area as the important driving force of promote regional urbanization and industrial structure transformation,its development affects profound the regional population agglomeration and urbanization of Henan Province. The industrial agglomeration area spatial planning is the prerequisite for promoting the orderly development of industrial agglomeration area,through the pre-planning of industrial agglomeration area in Henan Province in-depth research to identify current problems about industrial agglomeration area spatial planning,propose the idea of the joining together of five rules and production integration of the city,on this basis, adopt the industrial guidance,space overall guidance and policy measures to crack the problems of spatial planning about industrial agglomeration area,as well as industrial agglomeration area provide space planning methods and strategies guidance,and promoting the depth of integration between industrial agglomeration area and the city,to ensure the healthy development of industrial agglomeration area.

  12. Biomass fuel leaching for the control of fouling, slagging, and agglomeration in biomass power generation

    Science.gov (United States)

    Bakker, Robert Reurd

    economic potential of natural straw leaching is likely affected by risks associated with the largely unpredictable straw yield. In summary, leaching is an effective means of reducing fouling, slagging and bed agglomeration which occur during combustion of biomass fuels. Technical and economic challenges that are inherent to leaching or to biomass utilization at large exist that affect its economic potential.

  13. Bed Agglomeration During the Steam Gasification of a High Lignin Corn Stover Simultaneous Saccharification and Fermentation (SSF) Digester Residue

    Energy Technology Data Exchange (ETDEWEB)

    Howe, Daniel T.; Taasevigen, Danny J.; Gerber, Mark A.; Gray, Michel J.; Fernandez, Carlos A.; Saraf, Laxmikant; Garcia-Perez, Manuel; Wolcott, Michael P.

    2015-11-13

    This research investigates the bed agglomeration phenomena during the steam gasification of a high lignin residue produced from the simultaneous saccharification and fermentation (SSF) of corn stover in a bubbling fluidized bed. The studies were conducted at 895°C using alumina as bed material. Biomass was fed at 1.5 kg/hr, while steam was fed to give a velocity equal to 2.5 times the minimum fluidization velocity, with a steam/carbon ratio of 0.9. The pelletized feedstock was co-fed with a cooling nitrogen stream to mitigate feed line plugging issues. Tar production was high at 50.3 g/Nm3, and the fraction of C10+ compounds was greater than that seen in the gasification of traditional lignocellulosic feedstocks. Carbon closures over 94 % were achieved for all experiments. Bed agglomeration was found to be problematic, indicated by pressure drop increases observed below the bed and upstream of the feed line. Two size categories of solids were recovered from the reactor, +60 mesh and -60 mesh. After a 2.75-hour experiment, 61.7 wt % was recovered as -60 mesh particles and 38.2 wt% of the recovered reactor solids were +60 mesh. A sizeable percentage, 31.8 wt%, was +20 mesh. The -60 mesh particles were mainly formed by the initial bed material (Al2O3). Almost 50 wt. % of the + 20 mesh particles was found to be formed by organics. The unreacted carbon remaining in the reactor resulted in a low conversion rate to product gas. ICP-AES, SEM, SEM-EDS, and XRD confirmed that the large agglomerates (+ 20 mesh) were not encapsulated bed material but rather un-gasified feedstock pellets with sand particles attached to it.

  14. Factoring-in agglomeration of carbon nanotubes and nanofibers for better prediction of their toxicity versus asbestos

    Directory of Open Access Journals (Sweden)

    Murray Ashley R

    2012-04-01

    Full Text Available Abstract Background Carbon nanotubes (CNT and carbon nanofibers (CNF are allotropes of carbon featuring fibrous morphology. The dimensions and high aspect ratio of CNT and CNF have prompted the comparison with naturally occurring asbestos fibers which are known to be extremely pathogenic. While the toxicity and hazardous outcomes elicited by airborne exposure to single-walled CNT or asbestos have been widely reported, very limited data are currently available describing adverse effects of respirable CNF. Results Here, we assessed pulmonary inflammation, fibrosis, oxidative stress markers and systemic immune responses to respirable CNF in comparison to single-walled CNT (SWCNT and asbestos. Pulmonary inflammatory and fibrogenic responses to CNF, SWCNT and asbestos varied depending upon the agglomeration state of the particles/fibers. Foci of granulomatous lesions and collagen deposition were associated with dense particle-like SWCNT agglomerates, while no granuloma formation was found following exposure to fiber-like CNF or asbestos. The average thickness of the alveolar connective tissue - a marker of interstitial fibrosis - was increased 28 days post SWCNT, CNF or asbestos exposure. Exposure to SWCNT, CNF or asbestos resulted in oxidative stress evidenced by accumulations of 4-HNE and carbonylated proteins in the lung tissues. Additionally, local inflammatory and fibrogenic responses were accompanied by modified systemic immunity, as documented by decreased proliferation of splenic T cells ex vivo on day 28 post exposure. The accuracies of assessments of effective surface area for asbestos, SWCNT and CNF (based on geometrical analysis of their agglomeration versus estimates of mass dose and number of particles were compared as predictors of toxicological outcomes. Conclusions We provide evidence that effective surface area along with mass dose rather than specific surface area or particle number are significantly correlated with toxicological

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

    Science.gov (United States)

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

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

  16. What drives employment growth of Canadian Businesses? A Fresh Look at Indicators of Agglomeration Economies when Competition and Diversity Matter

    DEFF Research Database (Denmark)

    Wang, Cong; Steiner, Bodo

    2014-01-01

    This study investigates indicators of external scale economies in Canada for the period 2004-11. Accounting for firm-level external scale forces, we explore the extent to which external scale economies impact employment growth. Our analysis focuses on three factors: the impact of external scale...... economies accounting for Marshallian specialization and Jacobs diversity, competition by industry, and related and unrelated firm varieties in terms of employment and sales. Results accounting for non-linearity between employment growth and agglomeration suggest that in the short run, during the period 2004...

  17. Treatment of agglomerates of solid particles in suspension in a liquid in order to obtain a circulating mixture without deposits

    International Nuclear Information System (INIS)

    The invention concerns a process and an installation for treating agglomerates of solid particles in suspension in a liquid in order to obtain a circulating mixture without deposits. This process is notably used for reprocessing spent fuel after its cutting up, its dissolution in nitric solution and its decantation in a clarifier. Particles are conducted to a transferring tank, then circulated in a loop including a pomp and a dilacerator. Finally, the disaggregated particles are sifted and transferred to a vitrification site. The sifter can be ultrasonic, the dilacerator can be ultrasonic with Venturi tube or with Venturi tube and baffled system. A previous dilaceration can be done inside the clarifier. 6 figs

  18. EFFECTS OF PH ON AGGLOMERATION STATE OF Al2O3 – ZrO2 (ZTA NANOCOMPOSITE POWDERS SYNTHESIZED BY TARTARIC GEL METHOD

    Directory of Open Access Journals (Sweden)

    Mustafa Tuncer

    2012-07-01

    Full Text Available Alumina – 20 vol% zirconia (ZTA nanocomposites were synthesized by the tartaric acid sol-gel method. The precursors gelled from solutions at different pH were prepared and then calcined from 1000 to 1500°C. Surface area measurement (BET, X-ray diffraction (XRD, scanning electron microscopy (SEM and transmission electron microscopy (TEM were used to characterize the synthesized powders. Control of agglomeration state was carried out by changing the pH of the solution. Weakly agglomerated powders were obtained at pH=6, whereas the solution at pH=1 revealed hard agglomerated powders, (agglomeration degrees, N, were found to be 16425 at pH=1 and 102 at pH=6, respectively. The pH dependence of agglomeration was explained by the dissociation behavior of tartaric acid at various pH environments. XRD results showed that the powders have been fully tetragonal phase at 1000°C, while they exhibited tetragonal zirconia with minor monoclinic phase as well as a-Al2O3 at 1500°C. The presence of a-Al2O3 in the nanocrystalline composite contributes the wide range of temperature stability for t-ZrO2 up to 1500°C. TEM micrograph confirmed that alumina and zirconia were dispersed homogenously. Mechanical properties (hardness and indentation fracture toughness of sintered samples were also determined.

  19. Growth mechanisms for spherical mixed hydroxide agglomerates prepared by co-precipitation method: A case of Ni1/3Co1/3Mn1/3(OH)2

    International Nuclear Information System (INIS)

    Highlights: • Anisotropic growth of Ni1/3Co1/3Mn1/3(OH)2 along the [0 0 1] direction was revealed. • DFT calculation results show crystal surface energies of (0 0 1) plane is highest. • A new model was proposed to explain the formation of spherical agglomerates. - Abstract: Spherical Ni1/3Co1/3Mn1/3(OH)2 agglomerates were synthesized by the co-precipitation method in the presence of ammonia. The results show that the growth mechanism of spherical agglomerates follows three-stages, i.e. nucleation and anisotropic growth of single crystals; agglomeration of polycrystalline crystallites agglomerated by single crystal grains as primary particles to form embryonic agglomerates; formation, growth and consolidation of spherical agglomerates or particles by agglomeration of embryonic agglomerates, continued growth of individual crystals in the agglomerates and further attachment of primary particles. The first two stages are very fast while the last stage takes almost the entire process to complete. The main reason for the anisotropic growth of Ni1/3Co1/3Mn1/3(OH)2 crystal is that crystal surface energy of E(001), E(100), E(101) and E(102) is different with E(001) being the highest. The morphology of the final spherical agglomerates is explained by partial re-crystallization of contacting primary particles. The growth process of spherical agglomerates was examined by X-ray diffraction, scanning electron microscope, transmission electron microscope and calculation of crystal surface energy using density function theory

  20. Agglomeration and Collection of Fine Secondary Phases in Flowing Suspensions Utilizing Resonant Ultrasonic Fields.

    Science.gov (United States)

    Tolt, Thomas Lester

    1990-01-01

    A novel separation process based on a forced coincident excitation at ultrasonic frequencies in fluid filled tubes has been studied and developed for the agglomeration and collection of fine secondary phases in flowing suspensions. Under appropriate conditions, acoustic radiation forces can act to drive second phase inclusions to the nodes (or antinodes) of a stationary sound field and trap them there with a strength which can exceed the hydrodynamic drag exerted on the particles by a flowing fluid matrix. A review of the theoretical development of the acoustic forces acting on and between inclusions in a sound field is presented. The fields generated in a water bath using a lead zirconate -lead titanate piezoelectric disk acting a source of ultrasonic waves a short distance in front of a parallel reflector and in later experiments utilizing simple cylindrical chambers are compared to calculated stationary fields in Fabry-Perot laser resonators with parallel, plane finite mirrors. It is suggested that diffraction at the transducer and reflector surfaces is responsible for the creation of guided standing waves which have a nonuniform transverse distribution of acoustic velocity and pressure along nodal planes of minimum pressure spaced at intervals equal to one half of the acoustic wavelength in the fluid. This leads to the existence of transverse components in the acoustic radiation force in addition to an axially directed force which act to collect fine secondary phases into thin lens-shaped zones. Broadband piezoelectric transducers bonded to the ends of fluid filled glass and aluminum tubes (up to 4 cm in diameter and 25 cm in length, and ranging from 0.9 to 2 mm in wall thickness) were driven with continuous a.c. voltages at unique frequencies in the range of 0.35 to 1.4 Mhz to obtain a forced coincidence response in which the flexural vibrations of the tube wall are matched in phase and geometry with higher-order acoustic duct modes in the liquid. This

  1. Spatial structure and scale feature of the atmospheric pollution source impact of city agglomeration

    Institute of Scientific and Technical Information of China (English)

    XU; Xiangde; ZHOU; Xiuji; SHI; Xiaohui

    2005-01-01

    The spatial structure and multi-scale feature of the atmospheric pollution influence domain of Beijing and its peripheral areas (a rapidly developed city agglomeration) is dissected and analyzed in this paper on the basis of the atmospheric pollution dynamic-chemical process observation data of the urban building ensemble boundary layer of the Beijing City Air Pollution Observation Experiment (BECAPEX) in winter (February) and summer (August) 2003, and relevant meteorological elements and satellite retrieval aerosol optical depth (AOD), etc. comprehensive data with the dynamic-statistical integrated analysis of "point-surface" spatial structure. Results show that there existed significant difference in the contribution of winter/summer different pollution emission sources to the component character of atmospheric pollution, and the principal component analysis (PCA) results of statistical model also indicate that SO2 and NOX dominated in the component structure of winter aerosol particle; instead, CO and NOX dominated in summer. Surface layer atmospheric dynamic and thermal structures and various pollutant species at the upper boundary of building ensembles at urban different observational sites of Beijing in winter and summer showed an "in-phase" variation and its spatial scale feature of "influence domain". The power spectrum analysis (PSA) shows that the period spectrum of winter/summer particle concentration accorded with those of atmospheric wind field: the longer period was dominative in winter, but the shorter period in summer, revealing the impact of the seasonal scale feature of winter/summer atmospheric general circulation on the period of atmospheric pollution variations. It is found that from analyzing urban area thermal heterogeneity that the multiscale effect of Beijing region urban heat island (UHI) was associated with the heterogeneous expansion of tall buildings area. In urban atmospheric dynamical and thermal characteristic spatial structures, the

  2. Anthropogenic heat fluxes over Moscow agglomeration and other Russian and world cities

    Science.gov (United States)

    Belova, Iya; Ginzburg, Alexander

    2010-05-01

    Urbanization, particularly with respect to its sustainability, remains to be a great challenge in all regions of the world. Urbanization has an influence on soils, hydrology, and climate, these changes have effect on global climate, pollution, increase of anthropogenic greenhouse gases in the earth's atmosphere and human health. Thus anthropogenic heat flux is an important factor for estimation of development of global climate. The simple formula for anthropogenic heat fluxes (AHF) was proposed in the EGU General Assembly 2008 presentation [1] AHF = k × PD × EC, were PD is urban population density and EC is total energy consumption per capita. It was estimated that two of the world megacities - Seoul and Moscow - have the highest AHF values - 83 and 56 W/m2 correspondently. In presented paper it was studied the reasons of such high anthropogenic heat fluxes within Moscow region as well as AHF over the major Russian cities. It was shown that main reason of this circumstance is the administrative divisions in Moscow region. Moscow is ringed by Moscow circle motor road. Accordingly the city has sharply defined boundaries and densely populated residential suburbs are cut off and don't included in Moscow city administrative area. It was constructed the special graph to illuminate why Moscow city has such a high anthropogenic heat factor and how much Moscow agglomeration AHF could be if consider not only Moscow city itself but also the nearest suburb towns. Using the data from World Bank [2] and Russian governmental statistic agency [3] anthropogenic heat fluxes for Russian cities with population more than 500 000 were estimated. Energy consumption data for different Russian regions were calculated by special routine using in the Web-atlas [4]. This research is supported by RAS Fundamental Research Project 'Influence of anthropogenic heat fluxes and aerosol pollution on heat balance and climate of urbanized areas'. Other results of this project is presented in paper [5

  3. Fractal and agglomeration behavior in Gd and Sm doped CeO2 nano-crystalline powders

    International Nuclear Information System (INIS)

    Nanocrystalline Gd, Sm doped ceria powders were synthesized by a combustion technique, using glycine as the fuel. These powders, after calcination at 600 oC, were characterized by powder X-ray diffraction and were found to be phase pure. The crystallite sizes, as calculated from X-ray line broadening were in the range of 11-13 nm, which were in close agreement with those obtained from the SAXS studies. The TEM studies also showed the particle sizes to be in the range of 10-15 nm. These powders showed a high surface area as observed from BET technique. The extent and nature of agglomeration was studied by a particle size analyzer. The fractal behaviour of these nano-sized powders prepared by combustion synthesis, has also been investigated by small angle X-ray scattering technique. Results showed that the powders contain aggregates with rough fractal surfaces above a length scale of 20 nm. These parameters of the powders and their agglomerates were found to play a significant role in the sintering behavior

  4. Sources of organic pollution in particulate matter and soil of Silesian Agglomeration (Poland): evidence from geochemical markers.

    Science.gov (United States)

    Fabiańska, Monika J; Kozielska, Barbara; Konieczyński, Jan; Kowalski, Adam

    2016-06-01

    The exact input of particular sources to polycyclic aromatic hydrocarbons (PAHs) concentrations in urban and industrial agglomerations is still not well recognized. The major breakthrough is possible using geochemical markers. In the air aerosol and soil samples from areas located in the direct influence of industry/traffic in Silesian Agglomeration (Poland), PAHs and other organic compounds were analyzed, including geochemical markers (biomarkers) and polar compounds from fossil fuels and biomass. Gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS) were applied to investigate the composition of particulate matter and soil extracts. The results suggest that the predominant source of PAHs is fossil fuel. The presence and distribution of steranes, pentacyclic triterpenoids (i.e., hopanes and moretanes) and alkyl PAHs point to traffic emissions and fossil fuel combustion, mainly bituminous coal for power and heat purposes, as the main source of PAHs in the region. Moreover, the presence of fossil fuel biomarker in particulate matter and soil extracts from a rural site, previously considered to be free of organic pollution, requires a cautious interpretation for PAHs results. Apart from the fossil fuel, also other sources of contamination were identified in particulate matter extracts by their markers: phenols and levoglucosan for biomass and diisopropylnaphthalenes for printing materials combustion. The absence of polar biomass combustion indicators in soil extracts might be related to their higher reactivity. PMID:26362678

  5. Quantitative characterization of agglomerates and aggregates of pyrogenic and precipitated amorphous silica nanomaterials by transmission electron microscopy

    Directory of Open Access Journals (Sweden)

    De Temmerman Pieter-Jan

    2012-06-01

    Full Text Available Abstract Background The interaction of a nanomaterial (NM with a biological system depends not only on the size of its primary particles but also on the size, shape and surface topology of its aggregates and agglomerates. A method based on transmission electron microscopy (TEM, to visualize the NM and on image analysis, to measure detected features quantitatively, was assessed for its capacity to characterize the aggregates and agglomerates of precipitated and pyrogenic synthetic amorphous silicon dioxide (SAS, or silica, NM. Results Bright field (BF TEM combined with systematic random imaging and semi-automatic image analysis allows measuring the properties of SAS NM quantitatively. Automation allows measuring multiple and arithmetically complex parameters simultaneously on high numbers of detected particles. This reduces operator-induced bias and assures a statistically relevant number of measurements, avoiding the tedious repetitive task of manual measurements. Access to multiple parameters further allows selecting the optimal parameter in function of a specific purpose. Using principle component analysis (PCA, twenty-three measured parameters were classified into three classes containing measures for size, shape and surface topology of the NM. Conclusion The presented method allows a detailed quantitative characterization of NM, like dispersions of precipitated and pyrogenic SAS based on the number-based distributions of their mean diameter, sphericity and shape factor.

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

    Directory of Open Access Journals (Sweden)

    Christoph Bantz

    2014-10-01

    Full Text Available 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.

  7. Theoretical model for surface diffusion driven Ni-particle agglomeration in anode of solid oxide fuel cell

    Science.gov (United States)

    Gao, Sheng; Li, Jiayu; Lin, Zijing

    2014-06-01

    The agglomeration of Ni particles in nickel-yttria stabilized zirconia (YSZ) anode is an important degradation mechanism for the solid oxide fuel cell and is widely believed to be driven by surface diffusion. This work aims to develop a quantitative model to describe the agglomeration kinetics. The model treats the anode as a system of random packing Ni and YSZ particles. Surface diffusion occurs between the connected Ni particles of different sizes characterized by two representative radii, but is influenced by the YSZ network. The Fick's law for diffusion, the Gibbs-Thomson relation for vacancy concentration and the coordination number theory for percolating Ni network are employed in the mathematical derivation. The growth kinetics is expressed as an analytical function consisting of two model parameters, one for the Ni-particle size distribution and the other for the influence of the YSZ backbone. The model is in excellent agreement with the available experiments. The influence of the YSZ backbone is further considered to obtain a model with just one fitting parameter. The one-parameter model is also in good agreement with the experiments and the fundamental physics for the Ni-particle growth is therefore believed to be well characterized.

  8. Relationship between attachment probability and surface energy in adhesion process of gold particles to oil-carbon agglomerates

    Institute of Scientific and Technical Information of China (English)

    WU Xi-qing(伍喜庆); A.J. Monhemius; R.J. Gochin

    2003-01-01

    Based on the theoretical analyses, the adhesion process of fine gold particles to oil-carbon agglomerates in a dynamic system was quantitatively investigated in terms of the relationship between the attachment probability and the surface energy. The proposed way to establish this relationship is to firstly theoretically derive the formula to evaluate the surface energy change of the system by analyzing the adhesion process of a gold particle on an oil-carbon agglomerate in a mathematic and thermodynamic way. The obtained formula of the maximum energy change of unit surface area is, △ω'max =-1/2σhw (cosθ-1), which involves two measurable elements: interfacial tension and contact angle. In a well-quantified system, based on the related model it is also possible to calculate the complicated concept, namely, the attachment probability by transferring other measurable indices. In this way, after some adhesion experiments and measurements of relevant parameters, the empirical relationship between the attachment probability and the surface energy change was established in an exponential function, Pa =Aexp(-△Gsurf/k).

  9. Sustainable development of Shandong peninsula Peninsula urban agglomeration: a scenario analysis based on water shortage and water environment changes

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    China has experienced a rapid urbanization since late 1970s. The great increase of urban population has resulted in various environmental changes, of which urban water shortage and water environment problems have occurred in most cities, especially in the rapidly developing urban agglomerations in the eastern coastal region. This research, taking Shandong Peninsula Urban Agglomeration (SPUA) as a case study area, analyzes the urbanization expansion in the last decades, discusses the water shortage and water environment changes following the rapid economic development and urbanization such as groundwater sinking in the urban and plain area, sea water and salt-water intrusion in the coastal cities, water pollution overspreading and "water ecosystem degradation, and puts forwards some strategies for sustainability in populous regions with severe water shortage. Some countermeasures for sustainable development of SPUA are put forward, such as modern water resources inter-city networks to regulate water resource between cities, adjusting urbanization policy and urban scale planning to promote the development of small towns and medium sized cities, optimizing urban industry structure by restricting high water consumption enterprises and stimulating the growth of tertiary industry, improving water use efficient to reduce freshwater consumption and wastewater discharge, introducing economic means to water pricing and water management system. and restoring ecological conditions to strengthen the natural water-making capacity.

  10. Engineering Development of Advanced Physical Fine Coal Cleaning for Premium Fuel Applications: Task 9 - Selective agglomeration Module Testing and Evaluation.

    Energy Technology Data Exchange (ETDEWEB)

    Moro, N.` Jha, M.C.

    1997-09-29

    The primary goal of this project was the engineering development of two advanced physical fine coal cleaning processes, column flotation and selective agglomeration, for premium fuel applications. The project scope included laboratory research and bench-scale testing of both processes on six coals to optimize the processes, followed by the design, construction, and operation of a 2 t/hr process development unit (PDU). The project began in October, 1992, and is scheduled for completion by September 1997. This report summarizes the findings of all the selective agglomeration (SA) test work performed with emphasis on the results of the PDU SA Module testing. Two light hydrocarbons, heptane and pentane, were tested as agglomerants in the laboratory research program which investigated two reactor design concepts: a conventional two-stage agglomeration circuit and a unitized reactor that combined the high- and low-shear operations in one vessel. The results were used to design and build a 25 lb/hr bench-scale unit with two-stage agglomeration. The unit also included a steam stripping and condensation circuit for recovery and recycle of heptane. It was tested on six coals to determine the optimum grind and other process conditions that resulted in the recovery of about 99% of the energy while producing low ash (1-2 lb/MBtu) products. The fineness of the grind was the most important variable with the D80 (80% passing size) varying in the 12 to 68 micron range. All the clean coals could be formulated into coal-water-slurry-fuels with acceptable properties. The bench-scale results were used for the conceptual and detailed design of the PDU SA Module which was integrated with the existing grinding and dewatering circuits. The PDU was operated for about 9 months. During the first three months, the shakedown testing was performed to fine tune the operation and control of various equipment. This was followed by parametric testing, optimization/confirmatory testing, and finally a

  11. Engineering development of advanced physical fine coal cleaning for premium fuel applications. Task 6 -- Selective agglomeration laboratory research and engineering development for premium fuels

    Energy Technology Data Exchange (ETDEWEB)

    Moro, N.; Jha, M.C.

    1997-06-27

    The primary goal of this project is the engineering development of two advanced physical fine coal cleaning processes, column flotation and selective agglomeration, for premium fuel applications. The project scope included laboratory research and benchscale testing on six coals to optimize these processes, followed by the design, construction, and operation of a 2 t/hr process development unit (PDU). The project began in October, 1992, and is scheduled for completion by September 1997. This report represents the findings of Subtask 6.5 Selective Agglomeration Bench-Scale Testing and Process Scale-up. During this work, six project coals, namely Winifrede, Elkhorn No. 3, Sunnyside, Taggart, Indiana VII, and Hiawatha were processed in a 25 lb/hr continuous selective agglomeration bench-scale test unit.

  12. Diamond-like-carbon nanoparticle production and agglomeration following UV multi-photon excitation of static naphthalene/helium gas mixtures

    Science.gov (United States)

    Walsh, A. J.; Tielens, A. G. G. M.; Ruth, A. A.

    2016-07-01

    We report the formation of nanoparticles with significant diamond character after UV multi-photon laser excitation of gaseous naphthalene, buffered in static helium gas, at room temperature. The nanoparticles are identified in situ by their absorption and scattering spectra between 400 and 850 nm, which are modeled using Mie theory. Comparisons of the particles' spectroscopic and optical properties with those of carbonaceous materials indicate a sp3/sp2 hybridization ratio of 8:1 of the particles formed. The particle extinction in the closed static (unstirred) gas-phase system exhibits a complex and quasi-oscillatory time dependence for the duration of up to several hours with periods ranging from seconds to many minutes. The extinction dynamics of the system is based on a combination of transport features and particle interaction, predominantly agglomeration. The relatively long period of agglomeration allows for a unique analysis of the agglomeration process of diamond-like carbon nanoparticles in situ.

  13. Agglomeration of Ag and TiO2 nanoparticles in surface and wastewater: Role of calcium ions and of organic carbon fractions

    International Nuclear Information System (INIS)

    This study aims to investigate factors leading to agglomeration of citrate coated silver (AgNP-Cit), polyvinylpyrrolidone coated AgNPPVP and titanium dioxide (TiO2) nanoparticles in surface waters and wastewater. ENPs (1 mg/L) were spiked to unfiltered, filtered, ultrafiltered (<10 kDa and <1 kDa) samples. Z-average particle sizes were measured after 1 h, 1 day and 1 week. AgNP-PVP was stable in all fractions of the samples and kept their original size around 60 nm over 1 week. Agglomeration of AgNP-Cit and TiO2 was positively correlated with Ca2+ concentration, but dissolved organic carbon concentrations > 2 mg/L contributed to stabilizing these NP. Moreover, agglomeration of AgNP-Cit in the various organic matter fractions showed that high molecular weight organic compounds such as biopolymers provide stabilization in natural water. A generalized scheme for the agglomeration behavior of AgNP-Cit, AgNP-PVP and TiO2 in natural waters was proposed based on their relation with Ca2+, Mg2+ and DOC concentration. - Highlights: • Agglomeration of AgNP-Cit was positively correlated with Ca2+ concentration. • DOC > 2 mg/L contributes to stabilizing AgNP-Cit and TiO2. • High molecular weight biopolymers provide stabilization in natural water. • Z-average sizes of AgNP-Cit in filtered samples were higher than in unfiltered ones. • AgNP-PVP is stable in surface and wastewater over 1 week. - Agglomeration of ENP in natural waters and wastewater was mostly dependent on the calcium ion and dissolved organic carbon concentrations

  14. Investigation on pore structure and small-scale agglomeration behaviour in liquid phase sintered SiC using small angle neutron scattering

    Indian Academy of Sciences (India)

    D Sen; J Bahadur; S Mazumder; T Mahata; M Syambabu; P K Sinha

    2008-11-01

    Mesoscopic density fluctuations in liquid phase sintered silicon carbide have been investigated using small angle neutron scattering (SANS). The increase in the additives results in the modification in the pore size distribution and to some extent the total porosity. SANS revealed a mass fractal nature of the agglomerated matrix microstructure. The fractal dimension of the matrix does not change appreciably with the additives although the upper cut-off value of the fractal decreases significantly with the increase in the additives. The liquid phase sintering due to the presence of additives helps to achieve higher level of densification. However, the agglomeration hinders achievement of the fully dense pellets.

  15. DOES EU-INTEGRATION CHANGE AGGLOMERATION PROCESS? THE IMPACT OF EU MEMBERSHIP PROCESS ON THE CITY-SIZE DISTRIBUTION OF TURKEY

    Directory of Open Access Journals (Sweden)

    Engin Sorhun

    2013-02-01

    Full Text Available This paper aims to reveal the eventual impacts of European Union (EU membership process and other conventional factors on the city-size distribution of a candidate country (Turkey. I can state main results as follows: Analyzing from different estimation methods the direct effect of the EU reforms on agglomerating forces rather than congesting forces are revealed to be dominant for Turkey. However, the main impact of the EU membership process has positive but modest coefficient that indicate the weak willingness of the country for EU reforms.Keywords: Economic itegration, agglomeration, city-size distribution, EU, Turkey.JEL Classification: F15, F22, R12, R23

  16. CURRENT TRENDS OF THE REGIONAL DEVELOPMENT POLICY IN THE EUROPEAN UNION. THE DEVELOPMENT OF COMPETITIVE ECONOMIC AGGLOMERATIONS OF CLUSTER TYPE

    Directory of Open Access Journals (Sweden)

    LAURA CISMAŞ

    2010-01-01

    Full Text Available The study of economic agents’ behaviour, whose nowadays tendency is togroup themselves in space as clusters, has an important place in the field of localizing industrialactivities. This is due to domestic scale economies, known as agglomerations economies.According to Edgar M. Hoover (Hoover, 1948, domestic scale economies are specific tocompanies; the economies of localizing - to a certain branch, whose companies form clusters incertain geographical arias, and the urbanization economies are specific to cities, where thereare clusters of companies from different branches. The specialty literature regarding localeconomic development, based on the idea of cluster starts from well-known economic theories,such as: agglomeration theory (Alfred Marshall, the theory of spatial localizing of industrialunits (Alfred Weber, the theory of interdependence of locations (Harold Hotelling, the diamondtheory (Michael Porter, the theory of entrepreneurship (Joseph Schumpeter, the theory ofgeographical concentration. Basically, the common point which links them are the conceptswhich occur in these theories, such as: industrial district, industrial agglomeration, spatialinterdependence, concepts which lie at the basis of the cluster idea. Clusters represent animportant instrument for promoting industrial development, innovation, competitiveness andeconomic growth. If, at the beginning, the effort to develop clusters belonged to private personsand companies, nowadays, the actors involved in their development are the governments andpublic institutions of national or regional level.The objective established within the Lisbon Strategy (2000, to make the EuropeanUnion “the most competitive and dynamic knowledge-based economy”, is tightly linked to thenew approaches of the European economic policy, to competitiveness. One of the policies isfocused on developing at the European Union level clusters in the high competitiveness fields. with an innovative character

  17. Spatial structure and scale feature of the atmospheric pollution source impact of city agglomeration

    Institute of Scientific and Technical Information of China (English)

    XU Xiangde; ZHOU Xiuji; SHI Xiaohui

    2005-01-01

    The spatial structure and multi-scale feature of the atmospheric pollution influence domain of Beijing and its peripheral areas (a rapidly developed city agglomeration) is dissected and analyzed in this paper on the basis of the atmospheric pollution dynamic-chemical process observation data of the urban building ensemble boundary layer of the Beijing City Air Pollution Observation Experiment (BECAPEX) in winter (February) and summer (August) 2003, and relevant meteorological elements and satellite retrieval aerosol optical depth (AOD), etc. comprehensive data with the dynamic-statistical integrated analysis of "point-surface" spatial structure. Results show that there existed significant difference in the contribution of winter/summer different pollution emission sources to the component character of atmospheric pollution, and the principal component analysis (PCA) results of statistical model also indicate that SO2 and NOX dominated in the component structure of winter aerosol particle; instead, CO and NOX dominated in summer. Surface layer atmospheric dynamic and thermal structures and various pollutant species at the upper boundary of building ensembles at urban different observational sites of Beijing in winter and summer showed an "in-phase" variation and its spatial scale feature of "influence domain". The power spectrum analysis (PSA) shows that the period spectrum of winter/summer particle concentration accorded with those of atmospheric wind field: the longer period was dominative in winter, but the shorter period in summer, revealing the impact of the seasonal scale feature of winter/summer atmospheric general circulation on the period of atmospheric pollution variations. It is found that from analyzing urban area thermal heterogeneity that the multiscale effect of Beijing region urban heat island (UHI) was associated with the heterogeneous expansion of tall buildings area. In urban atmospheric dynamical and thermal characteristic spatial structures, the

  18. Evaluation of sanitary impact of urban air pollution. Agglomeration of Bayonne impact at short and long term; Evaluation de l'impact sanitaire de la pollution atmospherique urbaine. Agglomeration de Bayonne impact a cour et long terme

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-06-15

    A health impact assessment of air pollution based on the I.n.V.S. guidelines has been conducted in Bayonne according to the regional Plan for the quality of air in the region of Aquitaine. It has been carried out in 16 cities homogeneously exposed, belonging to Bayonne agglomeration, representing a study population of 148,742 inhabitants. Atmospheric pollution indicators analyzed are ozone, nitrogen dioxide and particles having diameter below 10 {mu}m. Short-term impact of atmospheric pollution has been estimated in term of mortality (total, cardiovascular and respiratory mortality) and on hospital intakes (for respiratory, cardiovascular and cardiac reasons) attributable to air pollution. Long term impact was also assessed by the number of deaths due to atmospheric pollution. In 2001, the atmospheric pollution has directly been responsible in the studied area for 20 anticipated deaths. A decrease by 25% of the pollutants could allow avoiding half of the premature deaths and hospital intakes attributable to air pollution. Concerning long term effects, a decrease by 5 {mu}g/m{sup 3} of the annual mean of PM{sub 10} could allow avoiding 32 deaths per year. These results should be interpreted with care because of the limits of the method. However, they show that air pollution impact is non negligible even in a small agglomeration like Bayonne, since everyone is exposed to air pollution. They also suggest that a policy of atmospheric pollution reduction only based on not exceeding the standard levels would not have the expected benefits on the public health point of view. To decrease at the source the everyday and total pollutants emissions would be more efficient. (author)

  19. Evaluation of sanitary impact of urban air pollution. Agglomeration of Perigueux impact at short and long term; Evaluation de l'impact sanitaire de la pollution atmospherique urbaine. Agglomeration de Perigueux impact a court et long terme

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-15

    A health impact assessment of air pollution based on the I.n.V.S. guidelines has been conducted in Perigueux according to the regional Plan for the quality of air in the region of Aquitaine. It has been carried out in 5 cities homogeneously exposed, belonging to Perigueux agglomeration, representing a study population of 52,948 inhabitants. Atmospheric pollution indicators analysed are ozone, nitrogen dioxide and particles having diameter below 10 {mu}m. Short-term impact of atmospheric pollution has been estimated in term of mortality (total, cardiovascular and respiratory mortality) and on hospital intakes (for respiratory, cardiovascular and cardiac reasons) attributable to air pollution. Long term impact was also assessed by the number of deaths due to atmospheric pollution. In 2001, the atmospheric pollution has directly been responsible in the studied area for 5 anticipated deaths. A decrease by 25% of the pollutants could allow avoiding half of the premature deaths and hospital intakes attributable to air pollution. Concerning long term effects, a decrease by 5 {mu}g/m{sup 3} of the annual mean of P.M.10 could allow avoiding 10 deaths per year. These results should be interpreted with care because of the limits of the method. However, they show that air pollution can have an impact even in a small agglomeration like Perigueux, since everyone is exposed to air pollution. They also suggest that a policy of atmospheric pollution reduction only based on not exceeding the standard levels would not have the expected benefits on the public health point of view. To decrease at the source the every day and total pollutants emissions would be more efficient. (author)

  20. Stretched Exponential Change of Magnetic Weight of Magnetite Ferrofluid: Distribution of Energy Barrier for Agglomeration of Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Daeseong; Kim, Hackjin [Chungnam National University, Taejeon (Korea, Republic of)

    2015-01-15

    Magnetic nanoparticles usually agglomerate reversibly under magnetic field. Magnetophoretic transport demonstrates the possibilities of the biomedical applications such as intercellular manipulation of magnetic nanoparticles for imaging or drug delivery. Magnetization of ferro fluid occurs by Neel and Brownian mechanism and aggregation of nanoparticles. We have recently reported the magnetization of magnetite ferro fluid studied by measuring the change of magnetic weight. The stretched exponential behaviors have been observed for the samples of different concentrations under various magnetic fields. When we study the transmission change of the fluid as like in Refs 2 and 12, the single or double exponential decay is observed, which suggests that the particle movement in the fluid is affected by diffusion but the structural relaxations of aggregates cause the stretched exponential dynamics.

  1. Stretched Exponential Change of Magnetic Weight of Magnetite Ferrofluid: Distribution of Energy Barrier for Agglomeration of Nanoparticles

    International Nuclear Information System (INIS)

    Magnetic nanoparticles usually agglomerate reversibly under magnetic field. Magnetophoretic transport demonstrates the possibilities of the biomedical applications such as intercellular manipulation of magnetic nanoparticles for imaging or drug delivery. Magnetization of ferro fluid occurs by Neel and Brownian mechanism and aggregation of nanoparticles. We have recently reported the magnetization of magnetite ferro fluid studied by measuring the change of magnetic weight. The stretched exponential behaviors have been observed for the samples of different concentrations under various magnetic fields. When we study the transmission change of the fluid as like in Refs 2 and 12, the single or double exponential decay is observed, which suggests that the particle movement in the fluid is affected by diffusion but the structural relaxations of aggregates cause the stretched exponential dynamics

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

    Science.gov (United States)

    Pandey, Arvind Chandra; Kumar, Amit

    2015-03-01

    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.

  3. Molecular structure, glass transition temperature variation, agglomeration theory, and network connectivity of binary P-Se glasses

    International Nuclear Information System (INIS)

    Raman scattering and 31P NMR results show that the backbone of binary PxSe1-x glasses is composed of Sen-chain fragments, pyramidal P(Se1/2)3 units, quasitetrahedral Se=P(Se1/2)3 units, and ethylenelike P2(Se1/2)4 units at low P content (xg(x) from agglomeration theory are compared to the observed Tg(x) trends established from temperature-modulated differential scanning calorimetry. The comparison shows that a stochastic network description is an appropriate one of glasses at low x (x0.47), a rapid phase separation of monomeric P4Se3 units from the backbone takes place, leading to a molecular glass with a rather low Tg at x>0.50

  4. Spatial-temporal characteristics and determinants of PM2.5 in the Bohai Rim Urban Agglomeration.

    Science.gov (United States)

    Wang, Zhen-bo; Fang, Chuang-lin

    2016-04-01

    Ambient particulate matter (PM) pollution of China has become a global concern and has great impact on air quality and human health. This paper adopts the PM2.5 concentration data obtained from 241 newly located observation points in the Bohai Rim Urban Agglomeration (BRUA), as well as economic, urban and industrial working population data in the study area, revealing the spatio-temporal distribution of PM2.5 and its determinants with the help of a spatial data model. The results indicate that: 1) The BRUA was the core area of PM2.5 pollution in China in 2014, the average PM2.5 concentration of which reached 74 μg/m(3), which is 13 μg/m(3) higher than the country average (61 μg/m(3)); 2) The PM2.5 concentration distribution had a characteristic of high in winter and autumn but low in spring and summer, presenting a U-shaped monthly profile and a U-impulse type daily profile; 3) The urban PM2.5 concentrations showed obvious spatial variation and agglomeration. The highest hot-spot was observed in spring, while the lowest was in summer. High concentration cities were mainly located in southern Hebei and western Shandong, and low concentration cities were in the coastal area around the Bohai Sea and the mountainous areas in northern Hebei. High hot-spot areas demonstrated an M-shaped change, with two cycles of advance and retreat from west to east. 4) The Geographically weighted regression (GWR) model shows that the GDP per capita, urbanization rate and construction of the cities were closely related to PM2.5 concentrations in the BRUA. PMID:26802272

  5. Modeling the contribution of long-term urbanization to temperature increase in three extensive urban agglomerations in China

    Science.gov (United States)

    Lin, Shan; Feng, Jinming; Wang, Jun; Hu, Yonghong

    2016-02-01

    This study simulated the effects of changes in the underlying surface induced by long-term urbanization on trends in surface air temperature (SAT) over three extensive urban agglomerations (Beijing-Tianjin-Hebei, BTH; the Yangtze River Delta, YRD; and the Pearl River Delta, PRD) in China during 1980-2009. To isolate the effects of continuous urban expansion on SAT with the least computation cost, we employed the Community Land Model (CLM4.5) in an off-line mode for a relatively long period. Based on a high-quality land use data set dating back to the 1980s, two scenarios were designed to represent the distributions of both nonurban and historically urban land use. By comparing the results of two numerical experiments, urban-induced warming in daily mean SAT (Tmean) over the three urban agglomerations, BTH, YRD, and PRD, were found to be 0.13°C/30 yrs, 0.12°C/30 yrs, and 0.09°C/30 yrs, contributing about 9.70%, 10.3%, and 9.68% to the mean long-term SAT trends, respectively. In addition, a higher contribution of urban-related warming was found in winter for BTH and in summer for the other two regions. However, urban-related warming had no significant effect on the trends of daily maximum SAT (Tmax) when compared with daily minimum SAT (Tmin). Specifically, at a local scale, the contributions of urban warming to the background warming in three representative cities, Beijing, Shanghai, and Guangzhou, were 12.7%, 29.0%, and 23.6%, respectively.

  6. Influence of agglomeration and specific lung lining lipid/protein interaction on short-term inhalation toxicity.

    Science.gov (United States)

    Wohlleben, Wendel; Driessen, Marc D; Raesch, Simon; Schaefer, Ulrich F; Schulze, Christine; Vacano, Bernhard von; Vennemann, Antje; Wiemann, Martin; Ruge, Christian A; Platsch, Herbert; Mues, Sarah; Ossig, Rainer; Tomm, Janina M; Schnekenburger, Jürgen; Kuhlbusch, Thomas A J; Luch, Andreas; Lehr, Claus-Michael; Haase, Andrea

    2016-09-01

    Lung lining fluid is the first biological barrier nanoparticles (NPs) encounter during inhalation. As previous inhalation studies revealed considerable differences between surface functionalized NPs with respect to deposition and toxicity, our aim was to investigate the influence of lipid and/or protein binding on these processes. Thus, we analyzed a set of surface functionalized NPs including different SiO2 and ZrO2 in pure phospholipids, CuroSurf(TM) and purified native porcine pulmonary surfactant (nS). Lipid binding was surprisingly low for pure phospholipids and only few NPs attracted a minimal lipid corona. Additional presence of hydrophobic surfactant protein (SP) B in CuroSurf(TM) promoted lipid binding to NPs functionalized with Amino or PEG residues. The presence of the hydrophilic SP A in nS facilitated lipid binding to all NPs. In line with this the degree of lipid and protein affinities for different surface functionalized SiO2 NPs in nS followed the same order (SiO2 Phosphate ∼ unmodified SiO2 < SiO2 PEG < SiO2 Amino NPs). Agglomeration and biomolecule interaction of NPs in nS was mainly influenced by surface charge and hydrophobicity. Toxicological differences as observed in short-term inhalation studies (STIS) were mainly influenced by the core composition and/or surface reactivity of NPs. However, agglomeration in lipid media and lipid/protein affinity appeared to play a modulatory role on short-term inhalation toxicity. For instance, lipophilic NPs like ZrO2, which are interacting with nS to a higher extent, exhibited a far higher lung burden than their hydrophilic counterparts, which deserves further attention to predict or model effects of respirable NPs. PMID:26984182

  7. The Effect of Urban Heat Island on Climate Warming in the Yangtze River Delta Urban Agglomeration in China

    Directory of Open Access Journals (Sweden)

    Qunfang Huang

    2015-07-01

    Full Text Available The Yangtze River Delta (YRD has experienced rapid urbanization and dramatic economic development since 1978 and the Yangtze River Delta urban agglomeration (YRDUA has been one of the three largest urban agglomerations in China. We present evidence of a significant urban heat island (UHI effect on climate warming based on an analysis of the impacts of the urbanization rate, urban population, and land use changes on the warming rate of the daily average, minimal (nighttime and maximal (daytime air temperature in the YRDUA using 41 meteorological stations observation data. The effect of the UHI on climate warming shows a large spatial variability. The average warming rates of average air temperature of huge cities, megalopolises, large cities, medium-sized cities, and small cities are 0.483, 0.314 ± 0.030, 0.282 ± 0.042, 0.225 ± 0.044 and 0.179 ± 0.046 °C/decade during the period of 1957–2013, respectively. The average warming rates of huge cities and megalopolises are significantly higher than those of medium-sized cities and small cities, indicating that the UHI has a significant effect on climate warming (t-test, p < 0.05. Significantly positive correlations are found between the urbanization rate, population, built-up area and warming rate of average air temperature (p < 0.001. The average warming rate of average air temperature attributable to urbanization is 0.124 ± 0.074 °C/decade in the YRDUA. Urbanization has a measurable effect on the observed climate warming in the YRD aggravating the global climate warming.

  8. An Experimental Investigation of Agglomeration with One and Two Nozzle Atomisation%单双喷嘴雾化凝聚的实验研究

    Institute of Scientific and Technical Information of China (English)

    Justin Nijdam; GUO Baoyu; Maritza Valencia-Bejarano; Timothy Langrish

    2004-01-01

    Water-droplet size and velocity measurements were taken throughout two different sprays produced by a single nozzle and two nozzles pointed towards each other. The aim of this investigation was to understand the manner in which the motion of the droplets in a spray leads to agglomeration of these droplets. It appears that the inertia of the droplets plays an important role in the redistribution of droplets throughout a spray. Larger droplets tend to concentrate at the outer portions of the spray, because they are able to maintain their radial momentum farther downstream of a nozzle, while the smaller droplets follow the airflow more closely and thus collect in the core of the spray. Agglomeration can result from both turbulent collisions and collisions due to the relative velocities of the droplets. The difference between the agglomeration rates in the sprays from a single nozzle and two-nozzles pointed towards each other was difficult to resolve in these experiments, although the results suggest that the outer portions of both sprays should be investigated more closely for evidence of agglomeration.

  9. Ash related bed agglomeration during fluidized bed combustion, further development of the classification method based on CCSEM; CCSEM-luokitusmenetelmaen jatkokehittaeminen tuhkan aiheuttaman agglomeroitumisen tutkimisessa leiju- ja kiertopetipoltossa

    Energy Technology Data Exchange (ETDEWEB)

    Laitinen, R.; Patrikainen, T.; Heikkinen, R.; Tiainen, M.; Virtanen, M. [Oulu Univ. (Finland). Inst. of Chemistry

    1997-10-01

    The scope of this project is to use the information and experience gained from the development of classification method to predict ash related problems like bed agglomeration during fluidised combustion. If boilers have to be shut down due to slagging or agglomeration of the bed material may cause significant economic losses for the entire energy production chain. Mineral classification methods based on the scanning electron microscopy are commonly used for coal ash investigation. In this work different biomass, peat, and peat-wood ash, fluidised-bed materials, and bed agglomerates were analysed with SEM-EDS combined with automatic image analysis software. The properties of ash particles are different depending on the fuel type. If biomass like wood or bark are added to peat the resulting ash has different properties. Due to the low mineral content in the original peat and to the fact that the majority of inorganic material is bound to the organic matrix, the classification has turned out to be less informative than was hoped. However, good results are obtained the by use of quasiternary diagrams. With these diagrams the distribution of particle composition is easily illustrated and thus meaningful prediction can be made of the slagging and agglomerating properties of ash. The content of ten different elements are determined for each particle by SEM-EDS combined with Link AIA software. The composition of the diagram corners can be varied Freely within these ten elements. (orig.)

  10. Agglomeration of tungsten carbide nanoparticles in exposure medium does not prevent uptake and toxicity toward a rainbow trout gill cell line.

    Science.gov (United States)

    Kühnel, Dana; Busch, Wibke; Meissner, Tobias; Springer, Armin; Potthoff, Annegret; Richter, Volkmar; Gelinsky, Michael; Scholz, Stefan; Schirmer, Kristin

    2009-06-28

    Due to their increased production and use, engineered nanoparticles are expected to be released into the aquatic environment where particles may agglomerate. The aim of this study was to explore the role of agglomeration of nanoparticles in the uptake and expression of toxicity in the rainbow trout (Oncorhynchus mykiss) gill cell line, RTgill-W1. This cell line was chosen as model because it is known to be amenable to culture in complete as well as greatly simplified exposure media. Nano-sized tungsten carbide (WC) with or without cobalt doping (WC-Co), two materials relevant in the heavy metal industry, were applied as model particles. These particles were suspended in culture media with decreasing complexity from L15 with 10% fetal bovine serum (FBS) to L15 to L15/ex, containing only salts, galactose and pyruvate of the complete medium L15. Whereas the serum supplement in L15 retained primary nanoparticle suspensions, agglomerates were formed quickly in L15 and L15/ex. Nevertheless, scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) elemental analysis revealed an uptake of both WC and WC-Co nanoparticles into RTgill-W1 cells irrespective of the state of agglomeration of nanoparticles. The localisation seemed to be restricted to the cytoplasm, as no particles were observed in the nucleus of cells. Moreover, reduction in cell viability between 10 and 50% compared to controls were observed upon particle exposure in all media although the pattern of impact varied depending on the medium and exposure time. Short-term exposure of cells led to significant cytotoxicity at the highest nominal particle concentrations, irrespective of the particle type or exposure medium. In contrast, long-term exposures led to preferential toxicity in the simplest medium, L15/ex, and an enhanced toxicity by the cobalt-containing WC nanoparticles in all exposure media. The composition of the exposure media also influenced the toxicity of the cobalt ions, which may

  11. Agglomeration of tungsten carbide nanoparticles in exposure medium does not prevent uptake and toxicity toward a rainbow trout gill cell line

    International Nuclear Information System (INIS)

    Due to their increased production and use, engineered nanoparticles are expected to be released into the aquatic environment where particles may agglomerate. The aim of this study was to explore the role of agglomeration of nanoparticles in the uptake and expression of toxicity in the rainbow trout (Oncorhynchus mykiss) gill cell line, RTgill-W1. This cell line was chosen as model because it is known to be amenable to culture in complete as well as greatly simplified exposure media. Nano-sized tungsten carbide (WC) with or without cobalt doping (WC-Co), two materials relevant in the heavy metal industry, were applied as model particles. These particles were suspended in culture media with decreasing complexity from L15 with 10% fetal bovine serum (FBS) to L15 to L15/ex, containing only salts, galactose and pyruvate of the complete medium L15. Whereas the serum supplement in L15 retained primary nanoparticle suspensions, agglomerates were formed quickly in L15 and L15/ex. Nevertheless, scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) elemental analysis revealed an uptake of both WC and WC-Co nanoparticles into RTgill-W1 cells irrespective of the state of agglomeration of nanoparticles. The localisation seemed to be restricted to the cytoplasm, as no particles were observed in the nucleus of cells. Moreover, reduction in cell viability between 10 and 50% compared to controls were observed upon particle exposure in all media although the pattern of impact varied depending on the medium and exposure time. Short-term exposure of cells led to significant cytotoxicity at the highest nominal particle concentrations, irrespective of the particle type or exposure medium. In contrast, long-term exposures led to preferential toxicity in the simplest medium, L15/ex, and an enhanced toxicity by the cobalt-containing WC nanoparticles in all exposure media. The composition of the exposure media also influenced the toxicity of the cobalt ions, which may

  12. Potential sensitivity of warm season precipitation to urbanization extents: Modeling study in Beijing-Tianjin-Hebei urban agglomeration in China

    Science.gov (United States)

    Wang, Jun; Feng, Jinming; Yan, Zhongwei

    2015-09-01

    In this study, we investigated how different degrees of urbanization affect local and regional rainfall using high-resolution simulations based on the Weather Research and Forecasting Model. The extreme rainfall event of 21 July 2012 in Beijing was simulated for three representative urban land use distributions (no urbanization, early urbanization level of 1980, and recent urbanization level of 2009). Results suggest that urban modification of rainfall is potentially sensitive to urban land use condition. Rainfall was increased significantly over the downwind Beijing metropolis because of the effects of early urbanization; however, recent conditions of high urban development caused no significant increase. Further comparative analysis revealed that positive urban thermodynamical effects (i.e., urban warming, increased sensible heat transportation, and enhanced convergence and vertical motions) play major roles in urban modification of rainfall during the early urbanization stage. However, after cities expand to a certain extent (i.e., urban agglomeration), the regional moisture depression induced by the prevalence of impervious urban land has an effect on atmospheric instability energy, which might negate the city's positive impact on regional rainfall. Additional results from regional climate simulations for 10 Julys confirm this supposition. Given the explosive urban population growth and increasing demand for freshwater in cities, the potential negative effects of the urban environment on precipitation are worth investigation, particularly in rapidly developing countries and regions.

  13. Heat supply systems using natural gas in the residential sector. The case of the agglomeration of Seoul

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hi-Chun [Department of Economics, Inha University, Yonghyun-Dong, Incheon 402-751 (Korea); Kim, Hoseok [Korea Environment Institute, 613-2, Bulkwang-Dong, Seoul 122-040 (Korea)

    2008-10-15

    Combined heat and power (CHP) and district heating (DH) promotion policies are based on the assumption of high energy efficiencies. In the last two decades, however, there has been a big increase in energy efficiencies of combined-cycle gas power plants (CCs) including CHPs and gas-condensing boilers. This study tries to verify the validity of the assumption of high energy efficiency of DH. The experience in the agglomeration of Seoul shows that DH in combination with large modern CHPs is not more energy efficient but substantially more expensive compared to individual gas heating by efficient condensing boilers in combination with CCs. We argue that the Korean government should review its CHP/DH support programs and abandon the so-called heat supply monopoly for DH operators in newly developed residential areas. Such a policy intervention only distorts the space heating market and wastes valuable financial resources. Furthermore, the public should be properly informed on energy efficiency as well as energy- and system-related costs of various heat supply systems. In the light of the present improvements in the performance of gas-condensing boilers and CCs, the validity of the assumption of high energy efficiency of CHP/DH in other countries has to be reviewed. (author)

  14. IR STUDY ON MONOMOLECULAR PARTICLE AGGLOMERATES OF POLYSTYRENE OBTAINED BY FREEZE-DRYING OF ITS DILUTE SOLUTION

    Institute of Scientific and Technical Information of China (English)

    Song Wang; Qing-hua Wang; Rong-shi Cheng

    2002-01-01

    The monomolecular particle agglomerates of polystyrenes were obtained by freeze-drying of its very dilutesolutions of 1.3 x 10-5-2.0 x 10-s g/mL in benzene:cylcohexane (100:1) solvents, and they were annealed at roomtemperature for hundred days before use. According to 13C-NMR measurement the polystyrenes should be practically atactic.The number average molecular weights of the samples are 2.80 x 103, 2.00 x 104, and 1.55 x 106, respectively. The freeze-dried aPS with a molecular weight higher than 104 show two new IR absorption bands at 1098 and 1261 cm-1, which areabsent in the normal aPS and freeze-dried styrene oligomer. it was also found that the low molecular weight samples canonly form powders, whereas the freeze-dried aPS with higher molecular weight form a mixture of powders and fibrils, ofwhich the longer fibrils show a much stronger 1261 cm-1 band than the shorter fibrils and the powder. It seems that the1261 cm-1 band corresponds to the stacking behavior of monomolecular particles.

  15. Distribution patterns and major sources of dioxins in soils of the Changsha-Zhuzhou-Xiangtan urban agglomeration, China.

    Science.gov (United States)

    Yang, Bing; Chen, Zhiliang; Zhang, Chaosheng; Dong, Jiahua; Peng, Xiaochun

    2012-10-01

    Surface soils from an industrial base, the Changsha-Zhuzhou-Xiangtan urban agglomeration in central China were analyzed for 2378-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). The PCDD/F concentrations ranged from 268 to 7510 pg g(-1) dry weight (dw), 72% of which were above the U.S. guideline value (1000 pg g(-1)). It was found that octachlorodibenzo-p-dioxin (OCDD) was the most dominant congener accounting for 78.4-99.3% of the total PCDD/Fs, which was consistent with the PCDD/F profiles reported in other Asian countries. It is recommended that the four major sources of PCDD/Fs in the region can be diesel-fuel vehicles, open straw burning, mass burn-water wall (MB-WW), pentachlorophenate (PCP)/PCP-Na and boilers-hazardous waste incineration. This study is one of the few studies with a focus on the PCDD/F pollution in central China, providing evidences for establishing priorities in reduction of ecological risks posed by PCDD/Fs in central China and elsewhere. PMID:22819566

  16. Comparison of reduction disintegration characteristics of TiO2-rich burdens prepared with sintering process and composite agglomeration process

    Science.gov (United States)

    Yu, Zheng-wei; Li, Guang-hui; Liu, Chen; Zhou, Feng; Peng, Zhi-wei; Jiang, Tao

    2016-04-01

    To reveal the impact of the composite agglomeration process (CAP) on the reduction disintegration properties of TiO2-rich ironmaking burden for a blast furnace, the reduction disintegration indices (RDIs), mineral constituents, and microstructure of the products prepared by the CAP and the traditional sintering process (TSP) were investigated. The results showed that, compared to the sinter with a basicity of 2.0 prepared by the TSP, the RDI+6.3 and the RDI+3.15 of the CAP product with the same basicity increased by 28.2wt% and 13.7wt%, respectively, whereas the RDI-0.5 decreased by 2.7wt%. The analysis of the mineral constituents and microstructure of the products indicated that the decreasing titanohematite content decreased the volume expansion during reduction. Meanwhile, the decreasing perovskite content decreased its detrimental effect on the reduction disintegration properties. In addition, the higher silicoferrite of calcium and aluminum (SFCA) content improved the strength of the CAP product. Together, these factors result in an improvement of the RDI of the CAP products. In addition, compared to the sinter, the reduced CAP products clearly contained fewer cracks, which also led to mitigation of reduction disintegration.

  17. On Index System and Quantitative Assessment of Eco-cities:A Case Study on Urban Agglomeration of the Yangtze Delta

    Institute of Scientific and Technical Information of China (English)

    Xiao Yali; Jiang Dahe; Wang Dan

    2007-01-01

    Urban agglomeration of the Yangtze Delta(UAYD),one of the most developed regions of China,has witnessed an increasing prevalence in building ecological cities when the ecological cities are pursued by many modem cities,and great achievements have been made in this regard.It is inevitable,however,that certain problems exist during the construction of ecological city,which include but not limited to non-harmonious development of urban complex ecosystem,and the difficulty in quantifying eco-city construction or incomplete quantification in assessing the construction of present and future eco-city.Based on the analysis on social-economic conditions and regional conditions of the UAYD,this paper attempts to set up an index system of eco-cities combining with local characteristics,and to adopt the indices of eco-city,urban harmony,and eco-city colligate to evaluate the ecological level,urban harmonious development and eco-city construction of cities within the UAYD.Results indicate that among 15 cities in UAYD,Suzhou City ranks the highest in terms of eco-city construction,whereas Nantong ranks relatively lower;sustainable eco-city construction is possible only when cities are developed in every respect of harmony.

  18. Reductions of PM2.5 in Beijing-Tianjin-Hebei urban agglomerations during the 2008 Olympic Games

    Science.gov (United States)

    Xin, Jinyuan; Wang, Yuesi; Wang, Lili; Tang, Guiqian; Sun, Yang; Pan, Yuepeng; Ji, Dongsheng

    2012-11-01

    The Atmospheric Environmental Monitoring Network successfully undertook the task of monitoring the atmospheric quality of Beijing and its surrounding area during the 2008 Olympics. The results of this monitoring show that high concentrations of PM2.5 pollution exhibited a regional pattern during the monitoring period (1 June-30 October 2008). The PM2.5 mass concentrations were 53 μg m-3, 66 μg m-3, and 82 μg m-3 at the background site, in Beijing, and in the Beijing-Tianjin-Hebei urban agglomerations, respectively. The PM2.5 levels were lowest during the 2008 Olympic Games (8-24 August): 35 μg m-3 at the background site, 42 μg m-3 in Beijing and 57 μg m-3 in the region. These levels represent decreases of 49%, 48%, and 56%, respectively, compared to the prophase mean concentration before the Olympic Games. Emission control measures contributed 62%-82% of the declines observed in Beijing, and meteorological conditions represented 18%-38%. The concentration of fine particles met the goals set for a "Green Olympics."

  19. Conditional versus unconditional industrial agglomeration: disentangling spatial dependence and spatial heterogeneity in the analysis of ICT firms' distribution in Milan

    Science.gov (United States)

    Espa, Giuseppe; Arbia, Giuseppe; Giuliani, Diego

    2013-01-01

    A series of recent papers have introduced some explorative methods based on Ripley's K-function (Ripley in J R Stat Soc B 39(2):172-212, 1977) analyzing the micro-geographical patterns of firms. Often the spatial heterogeneity of an area is handled by referring to a case-control design, in which spatial clusters occur as over-concentrations of firms belonging to a specific industry as opposed to the distribution of firms in the whole economy. Therefore, positive, or negative, spatial dependence between firms occurs when a specific sector of industry is seen to present a more aggregated pattern (or more dispersed) than is common in the economy as a whole. This approach has led to the development of relative measures of spatial concentration which, as a consequence, are not straightforwardly comparable across different economies. In this article, we explore a parametric approach based on the inhomogeneous K-function (Baddeley et al. in Statistica Nederlandica 54(3):329-350, 2000) that makes it possible to obtain an absolute measure of the industrial agglomeration that is also able to capture spatial heterogeneity. We provide an empirical application of the approach taken with regard to the spatial distribution of high-tech industries in Milan (Italy) in 2001.

  20. Graph-based Active Learning of Agglomeration (GALA: a Python library to segment 2D and 3D neuroimages

    Directory of Open Access Journals (Sweden)

    Juan eNunez-Iglesias

    2014-04-01

    Full Text Available The aim in high-resolution connectomics is to reconstruct complete neuronal connectivity in a tissue. Currently, the only technology capable of resolving the smallest neuronal processes is electron microscopy (EM. Thus, a common approach is to perform automatic segmentation of EM images, followed by manual proofreading by experts to fix errors. We developed an algorithm and software library to not only improve the accuracy of the initial automatic segmentation, but also point out the image coordinates where it is likely to have made errors. Our software, called gala (graph-based active learning of agglomeration, improves the state of the art in agglomerative image segmentation. It is implemented in Python and makes extensive use of the scientific Python stack (numpy, scipy, networkx, scikit-learn, scikit-image, and others. We present here the software architecture of the gala library, and discuss several designs that we consider would be generally useful for other segmentation packages. We also discuss the limitations of the gala library and how we intend to address them.

  1. To prevent the occurrence of black water agglomerate through delaying decomposition of cyanobacterial bloom biomass by sediment microbial fuel cell.

    Science.gov (United States)

    Zhou, Yan-Li; Jiang, He-Long; Cai, Hai-Yuan

    2015-04-28

    Settlement of cyanobacterial bloom biomass (CBB) into sediments in eutrophic lakes often induced the occurrence of black water agglomerate and then water quality deterioration. This study investigated the effect of sediment microbial fuel cell (SMFC) on CBB removal in sediments and related water pollution. Sediment bulking and subsequent black water from decomposition of settled CBB happened without SMFC, but were not observed over 100-day experiments with SMFC employment. While CBB in sediments improved power production from SMFC, the removal efficiency of organic matters in CBB-amended sediments with SMFC was significantly lower than that without SMFC. Pyrosequencing analysis showed higher abundances of the fermentative Clostridium and acetoclastic methanogen in CBB-amended bulk sediments without SMFC than with SMFC at the end of experiments. Obviously, SMFC operation changed the microbial community in CBB-amended sediments, and delayed the CBB degradation against sediment bulking. Thus, SMFC could be potentially applied as pollution prevention in CBB-settled and sensitive zones in shallow lakes. PMID:25621829

  2. Reductions of PM2.5 in Beijing-Tianjin-Hebei Urban Agglomerations during the 2008 Olympic Games

    Institute of Scientific and Technical Information of China (English)

    XIN Jinyuan; WANG Yuesi; WANG Lili; TANG Guiqian; SUN Yang; PAN Yuepeng; JI Dongsheng

    2012-01-01

    The Atmospheric Environmental Monitoring Network successfully undertook the task of monitoring the atmospheric quality of Beijing and its surrounding area during the 2008 Olympics.The results of this monitoring show that high concentrations of PM2.5 pollution exhibited a regional pattern during the monitoring period (1 June-30 October 2008).The PM2.5 mass concentrations were 53 μg m-3,66 μg m-3,and 82 μg m-3 at the background site,in Beijing,and in the Beijing-Tianjin-Hebei urban agglomerations,respectively.The PM2.5 levels were lowest during the 2008 Olympic Games (8-24 August):35 μg m-a at the background site,42 μg m-3 in Beijing and 57 μg m-3 in the region.These levels represent decreases of 49%,48%,and 56%,respectively,compared to the prophase mean concentration before the Olympic Games.Emission control measures contributed 62%-82% of the declines observed in Beijing,and meteorological conditions represented 18%-38%.The concentration of fine particles met the goals set for a "Green Olympics."

  3. Characterisation of (Th,U)O2 pellets fabricated by coated agglomerate pelletization process using XRD and SEM

    International Nuclear Information System (INIS)

    The need for intrinsic proliferation-resistant fuel having higher burnup, more manageable wastes, the advantage of in situ use of bred-in fissile material together with its abundance in the nature has led to a renewed interest in the thorium-based fuels and fuel cycles worldwide. India has a very ambitious three stage nuclear power programme to utilize its vast thorium reserves. Advanced Heavy Water Reactor (AHWR) is being developed in this direction which will have the driver fuel in the form of ThO2-233UO2 and ThO2-PuO2. The high gamma radiation associated with the short lived daughter products of 232U, which is always associated with 233U, necessitates remote reprocessing and refabrication of fuel. Coated agglomerate pelletization (CAP) route for fuel fabrication is being developed in Bhabha Atomic Research Centre (BARC), India for this purpose. The present paper summarizes the characterization of thoria-urania fuel fabricated by CAP process in terms of phase analysis and microstructure by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM)

  4. Influence of agglomeration of cerium oxide nanoparticles and speciation of cerium(III) on short term effects to the green algae Chlamydomonas reinhardtii

    International Nuclear Information System (INIS)

    Highlights: • Phosphate-dispersed CeO2 NP did not affect photosynthetic yield in C. reinhardtii. • Agglomerated CeO2 NP slightly decreased photosynthetic yield. • Cerium(III) was shown to affect photosynthetic yield and intracellular ROS level. • Slight effects of CeO2 NP were caused by dissolved Ce3+ ions present in suspensions. • Wild type and cell wall free mutant of C. reinhardtii showed the same sensitivity. - Abstract: Cerium oxide nanoparticles (CeO2 NP) are increasingly used in industrial applications and may be released to the aquatic environment. The fate of CeO2 NP and effects on algae are largely unknown. In this study, the short term effects of CeO2 NP in two different agglomeration states on the green algae Chlamydomonas reinhardtii were examined. The role of dissolved cerium(III) on toxicity, its speciation and the dissolution of CeO2 NP were considered. The role of cell wall of C. reinhardtii as a barrier and its influence on the sensitivity to CeO2 NP and cerium(III) was evaluated by testing both, the wild type and the cell wall free mutant of C. reinhardtii. Characterization showed that CeO2 NP had a surface charge of ∼0 mV at physiological pH and agglomerated in exposure media. Phosphate stabilized CeO2 NP at pH 7.5 over 24 h. This effect was exploited to test CeO2 NP dispersed in phosphate with a mean size of 140 nm and agglomerated in absence of phosphate with a mean size of 2000 nm. The level of dissolved cerium(III) in CeO2 NP suspensions was very low and between 0.1 and 27 nM in all tested media. Exposure of C. reinhardtii to Ce(NO3)3 decreased the photosynthetic yield in a concentration dependent manner with EC50 of 7.5 ± 0.84 μM for wild type and EC50 of 6.3 ± 0.53 μM for the cell wall free mutant. The intracellular level of reactive oxygen species (ROS) increased upon exposure to Ce(NO3)3 with effective concentrations similar to those inhibiting photosynthesis. The agglomerated CeO2 NP caused a slight decrease of

  5. Influence of agglomeration of cerium oxide nanoparticles and speciation of cerium(III) on short term effects to the green algae Chlamydomonas reinhardtii

    Energy Technology Data Exchange (ETDEWEB)

    Röhder, Lena A. [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, Dübendorf 8600 (Switzerland); ETH-Zurich, Institute of Biogeochemistry and Pollutant Dynamics, Zürich 8092 (Switzerland); Brandt, Tanja [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, Dübendorf 8600 (Switzerland); Sigg, Laura [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, Dübendorf 8600 (Switzerland); ETH-Zurich, Institute of Biogeochemistry and Pollutant Dynamics, Zürich 8092 (Switzerland); Behra, Renata, E-mail: Renata.behra@eawag.ch [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, Dübendorf 8600 (Switzerland)

    2014-07-01

    Highlights: • Phosphate-dispersed CeO₂ NP did not affect photosynthetic yield in C. reinhardtii. • Agglomerated CeO₂ NP slightly decreased photosynthetic yield. • Cerium(III) was shown to affect photosynthetic yield and intracellular ROS level. • Slight effects of CeO₂ NP were caused by dissolved Ce³⁺ ions present in suspensions. • Wild type and cell wall free mutant of C. reinhardtii showed the same sensitivity. - Abstract: Cerium oxide nanoparticles (CeO₂ NP) are increasingly used in industrial applications and may be released to the aquatic environment. The fate of CeO₂ NP and effects on algae are largely unknown. In this study, the short term effects of CeO₂ NP in two different agglomeration states on the green algae Chlamydomonas reinhardtii were examined. The role of dissolved cerium(III) on toxicity, its speciation and the dissolution of CeO₂ NP were considered. The role of cell wall of C. reinhardtii as a barrier and its influence on the sensitivity to CeO₂ NP and cerium(III) was evaluated by testing both, the wild type and the cell wall free mutant of C. reinhardtii. Characterization showed that CeO₂ NP had a surface charge of ~0 mV at physiological pH and agglomerated in exposure media. Phosphate stabilized CeO₂ NP at pH 7.5 over 24 h. This effect was exploited to test CeO₂ NP dispersed in phosphate with a mean size of 140 nm and agglomerated in absence of phosphate with a mean size of 2000 nm. The level of dissolved cerium(III) in CeO₂ NP suspensions was very low and between 0.1 and 27 nM in all tested media. Exposure of C. reinhardtii to Ce(NO₃)₃ decreased the photosynthetic yield in a concentration dependent manner with EC₅₀ of 7.5 ± 0.84 μM for wild type and EC₅₀ of 6.3 ± 0.53 μM for the cell wall free mutant. The intracellular level of reactive oxygen species (ROS) increased upon exposure to Ce(NO₃)₃ with effective concentrations similar to those inhibiting photosynthesis. The agglomerated Ce

  6. The factors that explain the major agglomeration of the industry of high technology in the north border of Mexico: the case of Matamoros and Reynosa

    Directory of Open Access Journals (Sweden)

    Jorge Alberto Pérez Cruz

    2014-01-01

    Full Text Available In the last three decades the geographical distribution of manufacturing change substantially, prompting new concentrations, particularly in the high tech industry. In this sense, the aim of this study is to know and analyze from the perspective of pecuniary and technological externalities factors that explain the change in the agglomeration of high-tech manufacturing. To do so,a questionnaire was applied to 55 manufacturing facilities located in Matamoros andReynosa in Tamaulipas. The results indicate that the highest concentration of high-tech industry has been motivated mainly by the geographic location of the municipalities, access to unskilled labor and cheap availability of urban infrastructure, among others. This means that there is no evidence for the pecuniary and technological externalities determine the agglomeration of high-tech industry in these cities.

  7. THE INFLUENCE OF AGGLOMERATIONS CONCERNING THE GENERATION OF EXTERNALITIES FOR ENTERPRISEShttp://dx.doi.org/10.5585/riae.v9i2.1673

    Directory of Open Access Journals (Sweden)

    Bruno Tavares

    2010-11-01

    Full Text Available This article aims to identify, through theoretical analysis, the influence agglomerations have in the generation of firm externalities. Hence, the idea is established by demonstrating that productive clusters are different, although largely ignored in a vast number of articles and in the development of public policies; which can be identified by the various existing typologies (Pedersen, 1997, Van Dijk; Sverrisson, 2003, SUZIGAN 2006. The study was based on the theory of productive clusters and in national and international empirical papers. Consequently, we conclude the agglomerations do not have equal potential to generate externalities, rather, it is expected the contribution that companies can receive is dependent upon the characteristics of each.  In addition, we propose a few approaches for companies, government agents and public policy makers.

  8. Multiple-Locus Departures from Panmictic Equilibrium within and between Village Gene Pools of Amerindian Tribes at Different Stages of Agglomeration

    OpenAIRE

    Smouse, Peter E.; Neel, James V.; Liu, Wanda

    1983-01-01

    A comparative analysis of departures from multiple-locus Hardy-Weinberg equilibrium is presented for a set of four tribal Indian groups (the Yanomama, Makiritare, Wapishana and Ticuna) from the lowlands of South America. These tribes span a range of agglomeration and acculturation from the most traditional, swidden horticulturalists to frontier townspeople. The small-group social organization typical of traditional horticulturalists leads to substantial departures from tribal panmixia, as man...

  9. SPATIAL AND SUPPLY/DEMAND AGGLOMERATION ECONOMIES: AN EVALUATION OF STATE-AND-INDUSTRY-LINKAGES IN THE U.S. FOOD SYSTEM

    OpenAIRE

    Cohen, Jeffrey P.; Morrison Paul, Catherine J.

    2001-01-01

    In this paper we postulate, measure, and evaluate the importance of cost-impacts from spatial and industrial spillovers for analysis of economic performance. To accomplish this, we incorporate measures of "activity levels" of related states and industries in a cost function model, and estimate their associated thick market and agglomeration effects in terms of shadow values and elasticities. We focus on the food processing sector, the proximity of own-industry activity in neighboring states, ...

  10. Spatial and Supply/Demand Agglomeration Economies: An Evaluation of State- and Industry-Linkages in the U.S. Food System

    OpenAIRE

    Cohen, Jeffrey P.; Morrison Paul, Catherine J.

    2001-01-01

    In this paper we postulate, measure, and evaluate the importance of cost-impacts from spatial and industrial spillovers for analysis of economic performance. To accomplish this, we incorporate measures of "activity levels" of related states and industries in a cost function model, and estimate their associated thick market and agglomeration effects in terms of shadow values and elasticities. We focus on the food processing sector, the proximity of own-industry activity in neighboring states...

  11. The Importance of Place, Space and Culture in the Development of an Industrial Agglomeration in Ireland: The Furniture Industry in Co. Monaghan

    OpenAIRE

    Mottiar, Ziene; Jacobson, David

    2002-01-01

    This article examines place, space and culture as factors in the development of industrial agglomerations. We argue that they are important concepts for industrial analysis which have, in part, been omitted by traditional neo-classical economists. We show the applicability of the framework in an investigation of the wooden furniture industrial district in County Monaghan, Ireland. The conclusion is that geographical location and concentration, external linkages with markets and supplie...

  12. 1D versus 3D quantum confinement in 1–5 nm ZnO nanoparticle agglomerations for application in charge-trapping memory devices

    Science.gov (United States)

    El-Atab, Nazek; Nayfeh, Ammar

    2016-07-01

    ZnO nanoparticles (NPs) have attracted considerable interest from industry and researchers due to their excellent properties with applications in optoelectronic devices, sunscreens, photocatalysts, sensors, biomedical sciences, etc. However, the agglomeration of NPs is considered to be a limiting factor since it can affect the desirable physical and electronic properties of the NPs. In this work, 1–5 nm ZnO NPs deposited by spin- and dip-coating techniques are studied. The electronic and physical properties of the resulting agglomerations of NPs are studied using UV–vis–NIR spectroscopy, atomic force microscopy (AFM), and transmission electron microscopy (TEM), and their application in metal-oxide-semiconductor (MOS) memory devices is analyzed. The results show that both dip- and spin-coating techniques lead to agglomerations of the NPs mostly in the horizontal direction. However, the width of the ZnO clusters is larger with dip-coating which leads to 1D quantum confinement, while the smaller ZnO clusters obtained by spin-coating enable 3D quantum confinement in ZnO. The ZnO NPs are used as the charge-trapping layer of a MOS-memory structure and the analysis of the high-frequency C–V measurements allow further understanding of the electronic properties of the ZnO agglomerations. A large memory window is achieved in both devices which confirms that ZnO NPs provide large charge-trapping density. In addition, ZnO confined in 3D allows for a larger memory window at lower operating voltages due to the Poole–Frenkel charge-emission mechanism.

  13. The influence of coal-associated trace elements on sintering and agglomeration of a model coal mineral mixture / M.V. Nel.

    OpenAIRE

    Nel, Marika Verita

    2009-01-01

    A series of experiments was conducted to investigate the potential influence of selected inorganic compounds on sintering and agglomeration of a model mineral mixture. The minerals and inorganic compounds were chosen based on the constituents found in coal. The study simulated ash formation processes in the temperature range of 500 °C to 1000 DC. The mineral mixture consisted of kaolinite, quartz, pyrite, siderite, calcite, Ti02 and magnesite in a fIxed ratio. The mixture was ...

  14. 1D versus 3D quantum confinement in 1-5 nm ZnO nanoparticle agglomerations for application in charge-trapping memory devices.

    Science.gov (United States)

    El-Atab, Nazek; Nayfeh, Ammar

    2016-07-01

    ZnO nanoparticles (NPs) have attracted considerable interest from industry and researchers due to their excellent properties with applications in optoelectronic devices, sunscreens, photocatalysts, sensors, biomedical sciences, etc. However, the agglomeration of NPs is considered to be a limiting factor since it can affect the desirable physical and electronic properties of the NPs. In this work, 1-5 nm ZnO NPs deposited by spin- and dip-coating techniques are studied. The electronic and physical properties of the resulting agglomerations of NPs are studied using UV-vis-NIR spectroscopy, atomic force microscopy (AFM), and transmission electron microscopy (TEM), and their application in metal-oxide-semiconductor (MOS) memory devices is analyzed. The results show that both dip- and spin-coating techniques lead to agglomerations of the NPs mostly in the horizontal direction. However, the width of the ZnO clusters is larger with dip-coating which leads to 1D quantum confinement, while the smaller ZnO clusters obtained by spin-coating enable 3D quantum confinement in ZnO. The ZnO NPs are used as the charge-trapping layer of a MOS-memory structure and the analysis of the high-frequency C-V measurements allow further understanding of the electronic properties of the ZnO agglomerations. A large memory window is achieved in both devices which confirms that ZnO NPs provide large charge-trapping density. In addition, ZnO confined in 3D allows for a larger memory window at lower operating voltages due to the Poole-Frenkel charge-emission mechanism. PMID:27232717

  15. Internalization and cytotoxicity effects of carbon-encapsulated iron nanoparticles in murine endothelial cells: Studies on internal dosages due to loaded mass agglomerates.

    Science.gov (United States)

    Cywinska, Monika A; Bystrzejewski, Michal; Poplawska, Magdalena; Kosmider, Anita; Zdanowski, Robert; Lewicki, Slawomir; Fijalek, Zbigniew; Ostrowska, Agnieszka; Bamburowicz, Magdalena; Cieszanowski, Andrzej; Grudzinski, Ireneusz P

    2016-08-01

    Carbon-encapsulated iron nanoparticles (CEINs) qualified as metal-inorganic hybrid nanomaterials offer a potential scope for an increasing number of biomedical applications. In this study, we have focused on the investigation of cellular fate and resulting cytotoxic effects of CEINs synthesized using a carbon arc route and studied in murine endothelial (HECa-10) cells. The CEIN samples were characterized as pristine (the mean diameter between 47 and 56nm) and hydrodynamic (the mean diameter between 270 and 460nm) forms and tested using a battery of methods to determine the cell internalization extent and cytotoxicity effects upon to the exposures (0.0001-100μg/ml) in HECa-10 cells. Our studies evidenced that the incubation with CEINs for 24h is accompanied with substantial changes of Zeta potential in cells which can be considered as a key factor for affecting the membrane transport, cellular distribution and cytotoxicity of these nanoparticles. The results demonstrate that CEINs have entered the endothelial cell through the endocytic pathway rather than by passive diffusion and they were mainly loaded as agglomerates on the cell membrane and throughout the cytoplasm, mitochondria and nucleus. The studies show that CEINs induce the mitochondrial and cell membrane cytotoxicities in a dose-dependent manner resulting from the internal dosages due to CEIN agglomerates. Our results highlight the importance of the physicochemical characterization of CEINs in studying the magnetic nanoparticle-endothelial cell interactions because the CEIN mass agglomerates can sediment more or less rapidly in culture models. PMID:27107485

  16. Change the number of water reservoirs in the selected cities of the Upper Silesian Agglomeration over the period 1993-2014

    Directory of Open Access Journals (Sweden)

    Dąbrowska Dominika

    2015-06-01

    Full Text Available The Upper Silesian Agglomeration is the most industrialized area in Poland and one of the most in Europe. It is situated in the eastern part of the Upper Silesia and covers nearly 1500 km2. This region is highly diverse in terms of the spatial structure. There are lots of water reservoirs besides built-up areas and industrial facilities. Many of them have also significance for nature. Water reservoirs in the Upper Silesian Agglomeration function under anthropogenic conditions. Water reservoirs have a different size and the genesis. This kind of occurrence conditions influences the water reservoirs` state. There are mainly water reservoirs of anthropogenic character in a study area. A lot of water reservoirs are strictly connected with coal exploitation in this region. Unfortunately, the number of water reservoirs in the cities of the Upper Silesian Agglomeration has lately decreased. Reservoirs are eliminated as a result of changes in industry, progressive land development, changes in environmental conditions. In this paper we present the results of the number of water reservoirs analysis in Katowice, Sosnowiec and Chorzów over the period 1993-2014. Field studies and analysis of topographic maps show a decrease in the number of water reservoirs in this region by tens of percent.

  17. Evaluation of sanitary impact of urban air pollution. Agglomeration of Agen impact at short and long term; Evaluation de l'impact sanitaire de la pollution atmospherique urbaine. Agglomeration d'Agen impact a court et long terme

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    A health impact assessment of air pollution based on the I.n.V.S. guidelines has been conducted in Agen according to the regional Plan for the quality of air in the region of Aquitaine to assess short term effects of pollutants on morbidity (hospital admissions in 2002) and mortality (deaths in 2001), and long-term effects on mortality. This study is based on the four standardised steps of health risk assessment. It has been carried out in 8 cities homogeneously exposed, belonging to Agen agglomeration, representing a study population of 60,515 inhabitants. Atmospheric pollution indicators analysed are ozone and particles having diameter below 10 {mu}m. Short-term impact of atmospheric pollution has been estimated in term of mortality (total, cardiovascular and respiratory mortality) and on hospital intakes (for respiratory, cardiovascular and cardiac reasons) attributable to air pollution.Long-term impact was also assessed by the number of deaths due to atmospheric pollution. In 2001, the atmospheric pollution has directly been responsible in the studied area of 4 anticipated deaths, including 2 for cardiovascular reason. A decrease by 25% of the pollutants could allow avoiding 2 premature deaths per year among the 4 attributable to air pollution. Concerning long-term effects, a decrease by 5 {mu}g/m{sup 3} of the annual mean of P.M.10 would allow avoiding 11 premature deaths per year. The results of this study should be interpreted with care because of the limits of the method. However, they show that air pollution can have a health impact even in a small city like Agen, since everyone is exposed to air pollution. (author)

  18. Theory and Practice in Deep Integration of Provincial Urban Agglomeration:A Case of Zhongyuan Urban Agglomeration%省域城市群深度整合的理论与实践研究——以中原城市群为例

    Institute of Scientific and Technical Information of China (English)

    王发曾; 闫卫阳; 刘静玉

    2011-01-01

    In the first half of the 21 st century, urban agglomerations on various spatial scales will play an important role in China's socio-economic development, and provincial urban agglomerations are bound to become the major basis of the province development strategy. Based on the study on the cohesion and outreach of Zhongyuan urban agglomeration, the paper deepens the integration theory of provincial urban agglomeration. The conclusion as follows: 1 ) Cohesion means to create the modem metropolitan area, and build core growth pole to drive the rapid development of urban agglomeration. Outreach means to create modem provincial urban system, and build regional support system to host the healthy development of urban agglomeration. 2) The Zhongyuan urban agglomeration comprises the four industrial zones and developmental axes. 3 ) Zhongyuan urban agglomeration cohesions in the municipal district of Zhengzhou-Kaifeng, which can be divided into five functional regions. And the construction of industrial zone in Zhengzhou-Kaifeng should be gone firstly as the important ingredient of the key functional region. 4) Zhongyuan urban agglomeration outreaches in the urban system of Henan Province,which has two intensive projects of building platform for the urbanism and brought its whole functions into play.And 5 ) in the strategic planning of Zhongyuan Economic Zone, Zhongyuan urban agglomeration is still the major distraction slabs, which integration, cohesion and outreach will give important support for Zhongyuan Economic Zone and play a key role on national development.%21世纪前半叶,各种空间尺度的城市群将在我国经济社会发展中扮演重要角色,省域城市群必然成为省(区)发展战略的主要牵引板块.一方面,省域城市群的深度整合迫切需要城市群理论与方法的指导与支撑;另一方面,城市群整合理论需要通过城市群建设实践进行提炼与升华,并在实践中进一步验证.通过中原城市群初步整

  19. Differences between satellite- and ground-based urban heat island effect - Case study for the Budapest agglomeration area

    Science.gov (United States)

    Pongracz, R.; Bartholy, J.; Lelovics, E.; Dezso, Z. S.; Dobi, I.

    2012-04-01

    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 Pestszentlőrinc); 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

  20. Thermal desorption and recycling of volatile selective binders used in solid wastes deashing; Desorption thermique et recyclage d'agglomerants selectifs volatils utilises en decendrage de residus solides

    Energy Technology Data Exchange (ETDEWEB)

    Bensakhria, A.; Sajet, P.; Antonini, G. [Universite de Technologie de Compiegne, Centre de Recherches de Royallieu UMR 6067, Genie des Procedes Industriels, 60 - Compiegne (France)

    2001-07-01

    A pilot unit for the deashing of coal tailings by selective agglomeration and recovery of the binder/water mixture by azeotropic desorption of binders has been tested. The effect of different experiment parameters on the deashing efficiency, on the recovery and recycling of the binding agent have been tested. A 90% deashing level with a 94% recovery of the carbonaceous matter has been obtained with a recycling level of about 82% for the agglomerating agent. (J.S.)

  1. From environmental noise abatement to soundscape creation through strategic noise mapping in medium urban agglomerations in South Europe.

    Science.gov (United States)

    Vogiatzis, Konstantinos; Remy, Nicolas

    2014-06-01

    In the framework of the European Directive 2002-49-EU, the medium sized cities of Volos and Larissa in central Greece recently completed (2012) their strategic noise maps and relevant action plans that define the main strategies to reduce noise exposure of residents and introduce and preserve "quite zones". For the first time in this framework, it has been decided to introduce, as well, a general study for five specific urban districts covering not only the measurement and modeling of environmental noise levels but also qualitative surveys on the sound perception by the residents and several analyses of the urban and architectural tissue. The districts (respectively four in Volos and one in Larissa with the two of them in the center of both agglomerations) were chosen as representatives of urban situations due to their proximity to transportation infrastructures (main road network, industrial harbor facilities and both regional and intercity train network) and also because they represent different urban typologies (residential district, downtown area with or without shops, more or less densely populated neighborhood, etc.…). Sociological surveys on sound and noise perception have been implemented on some 15% of the residents per district using opened questionnaires. Soundscape analysis was also conducted through qualitative criteria. A cross-analysis of these data explains in detail the physical reasons for the existence of sound qualities that contribute to the identity of each distinct neighborhood. This paper, in a strategic plan level, has introduced valuable recommendations in order not only to preserve the sound quality on the existing sites but also to authorize developers and decision makers (mayors, architects, town planners) to evolve them positively over time. PMID:23992742

  2. Estimation Terrestrial Net Primary Productivity Based on CASA Model: a Case Study in Minnan Urban Agglomeration, China

    International Nuclear Information System (INIS)

    Net Primary Productivity (NPP) is a key component of the terrestrial carbon cycle. The research of net primary productivity will help in understanding the amount of carbon fixed by terrestrial vegetation and its influencing factors. Model simulation is considered as a cost-effective and time-efficient method for the estimation of regional and global NPP. In the paper, a terrestrial biosphere model, CASA (Carnegie Ames Stanford Approach), was applied to estimate monthly NPP in Minnan urban agglomeration (i.e. Xiamen, Zhangzhou and Quanzhou cities) of Fujian province, China, in 2009 and 2010, by incorporating satellite observation of SPOT Vegetation NDVI data together with other climatic parameters and landuse map. The model estimates average annual terrestrial NPP of Minnan area as 16.3 million Mg C. NPP decreased from southwest to the northeast. The higher NPP values exceeding 720 gC·m− 2·a −1 showed in North Zhangzhou city and lower values under 500 gC·m− 2·a −1 showed in the some areas of northeast Quanzhou city. Seasonal variations of NPP were large. It was about 45% of the total annual NPP in the three months in summer, and the NPP values were very low in winter. From 2009 to 2010, the value of annual NPP showed a slightly decrease trend, approximately 7.8% because the annual temperature for 2010 decline 13.6% compared with 2009 in despite of an increase in rainfall of about 34.3%. The results indicate that temperature was a main limiting factor on vegetation growth, but water is not a limiting factor in the rainy area

  3. The influence of fine char particles burnout on bed agglomeration during the fluidized bed combustion of a biomass fuel

    Energy Technology Data Exchange (ETDEWEB)

    Scala, Fabrizio; Chirone, Riccardo [Istituto di Ricerche sulla Combustione, CNR, P.le V. Tecchio, 80-80125 Naples (Italy); Salatino, Piero [Dipartimento di Ingegneria Chimica, Universita degli Studi di Napoli Federico II, P.le V. Tecchio, 80-80125 Naples (Italy)

    2003-11-15

    The combustion of biomass char in a bubbling fluidized bed is hereby addressed, with specific reference to the influence that the combustion of fine char particles may exert on ash deposition and bed agglomeration phenomena. Experiments of steady fluidized bed combustion (FBC) of powdered biomass were carried out with the aim of mimicking the postcombustion of attrited char fines generated in the fluidized bed combustion of coarse char. Experimental results showed that the char elutriation rate is much smaller than expected on the basis of the average size of the biomass powder and of the carbon loading in the combustor. Samples of bed material collected after prolonged operation of the combustor were characterized by scanning electron microscopy (SEM)-EDX analysis and revealed the formation of relatively coarse sand-ash-carbon aggregates. The phenomenology is consistent with the establishment of a char phase attached to the bed material as a consequence of adhesion of char fines onto the sand particles. Combustion under sound-assisted fluidization conditions was also tested. As expected, enhancement of fines adhesion on bed material and further reduction of the elutriation rate were observed. Experimental results are interpreted in the light of a simple model which accounts for elutriation of free fines, adhesion of free fines onto bed material and detachment of attached fines by attrition of char-sand aggregates. Combustion of both free and attached char fines is considered. The parameters of the model are assessed on the basis of the measured carbon loadings and elutriation rates. Model computations are directed to estimate the effective size and the peak temperature of char-sand aggregates. The theoretical estimates of the effective aggregate size match fairly well those observed in the experiments.

  4. An elaborate high resolution emission inventory of primary air pollutants for the Central Plain Urban Agglomeration of China

    Science.gov (United States)

    Qiu, Peipei; Tian, Hezhong; Zhu, Chuanyong; Liu, Kaiyun; Gao, Jiajia; Zhou, Junrui

    2014-04-01

    A high resolution emission inventory of primary air pollutants was developed based on the detailed collected activity data and the latest source-specific emission factors for the year 2010 in the Central Plain Urban Agglomeration (CPUA) region of China. The total emissions of SO2, NOx, PM10, PM2.5, CO, VOCs, and NH3 were estimated to be about 863.7 kt, 1058.2 kt, 1180.4 kt, 753.2 kt, 2854.3 kt, 466.1 kt, and 496.0 kt, respectively. Therein, power plants were demonstrated to be the largest sources for NOx, contributing about 36.1% of total emissions; industrial processes and biomass burning sources were proved to be the two major contributors of PM10, PM2.5 and VOCs emissions, together accounting for about 71.1%, 79.2% and 56.9% of the total emissions respectively. Besides, 18.4% of VOCs emissions can be explained by VOCs product-related sources. Other stationary combustion sources accounted for 57.7% of SO2 and 30.3% of CO emissions, respectively. Livestock and N-fertilizer application sources contributed about 81.0% of NH3 emissions together. Further, the emissions were spatially distributed into grid cells with a resolution of 3 km × 3 km, by using spatial allocation surrogates such as high resolution gridded population density and regional GDP. This inventory will benefit for policymakers and researchers to better understand the current situation of complex air pollution in the CPUA region of China and supply important necessary input for regional air quality modeling and policymaking.

  5. Prevention of Bed Agglomeration Problems in a Fluidized Bed Boiler by Finding the Trigging Value of Sewage Sludge Dosage Added to Combustion of Biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Kajsa; Gervind, Pernilla

    2009-07-01

    Agglomeration of bed sand is a common problem during combustion of biofuels with high ash content in fluidized bed boilers. Former studies have shown that co-combustion of biofuels with sewage sludge increases the agglomeration temperature. Sewage sludge has a low heating value and high ash content. It would therefore be better to use sludge as an additive to the combustion than as a co-combusted biofuel. In this study the trigging value of sludge addition to the combustion of some biofuel was investigated. The effect of adding sludge with different precipitation chemicals, iron sulphate and aluminium sulphate, was investigated. The biofuels used for the experiments were bark, refused derived fuel (RDF) and a mixture of wood and straw, 75/25 % on energy basis. All experiments were carried out in a laboratory scale fluidized bed reactor. Analyses of chemical composition of bed sand and SEM/EDX analyses were performed after the combustion. Eventually agglomeration tests were performed in order to find the agglomeration temperature of the samples. Some of the samples sintered during the combustion and were not tested for the agglomeration temperature. SEM/EDX showed that all samples of bed sand contained sand particles with more or less coatings. In some cases the coatings seemed to consist of one dense inner layer and one more porous outer layer. From SEM/EDX and chemical composition analyses it was found that the total amount of phosphorous in the bed sand samples was increased with an increased addition of sludge in all experiments. The concentration of phosphorous was especially higher in the outer layers/coatings. It was also found that elements from the sludge seem to get caught by a sticky layer at the bed sand surface and form a non-sticky or less sticky layer that prevents agglomeration. The total amount of aluminium was increased with an increased addition of sludge for the wood/straw samples, while it increased with an increased amount of combusted fuel for

  6. Effects of temperature and initial molar ratio of Na2O to Al2O3 on agglomeration of fine AI(OH)3 seed in synthetic Bayer solution

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Fine AI(OH)3 crystals were aggregated from supersaturated aluminate solution in the batch reaction tanks.By means of laser particle size analyzer and scanning electron microscopy,the influences of temperature and initial molar ratio of Na2O to A12O3 (αK) on agglomeration of fine seed in Bayer process were investigated.The results show that agglomeration is almost finished in 8 h,and seeds with size less than 2 μm are easily aggregated together,and almost disappear in 8 h under the optimal process conditions.In the aluminate solution with the same moderate initial αK,when the reaction temperature reaches 75 ℃,the secondary nucleation does not occur,and the effect of agglomeration is better.And at the same reaction temperature,when the initial αK is 1.62,the initial supersaturation of aluminate solution is moderate,the binders on the surfaces of the seed are enough to maintain the agglomeration process,and the agglomeration degree is better.From SEM images,agglomeration mainly occurs in the fine particles,the combinations among the fine particles are loose and the new formed coarse crystal shapes are irregular.

  7. Bed agglomeration risk related to combustion of cultivated fuels (wheat straw, red canary grass, industrial hemp) in commercial bed materials; Baeddagglomereringsrisk vid foerbraenning av odlade braenslen (hampa, roerflen, halm) i kommersiella baeddmaterial

    Energy Technology Data Exchange (ETDEWEB)

    Erhardsson, Thomas; Oehman, Marcus; Geyter, Sigrid de; Oehrstroem, Anna

    2006-12-15

    The market of forest products is expanding and thus resulting in more expensive biomass fuels. Therefore research within the combustion industry for alternative fuels is needed, for example cultivated fuels. Combustion and gasification research on these cultivated fuels are limited. The objectives of this work was to increase the general knowledge of silicon rich cultivated fuels by study the agglomeration characteristics for wheat straw, reed canary grass and industrial hemp in combination with commercial bed materials. Controlled fluidized bed agglomeration tests was conducted in a 5 kW, bench-scale, bubbling fluidized bed reactor. The tendencies of agglomeration were determined with the three cultivated fuels in combination with various minerals present in natural sand (quarts, plagioclase and potassium feldspar) and an alternative bed material (olivine). During the experiments bed samples and formed agglomerates were collected for further analyses with a scanning electron microscope (SEM) and with X-ray microanalysis (EDS). Wheat straw had the highest agglomeration tendency of the studied fuels followed by reed canary grass and industrial hemp. No significant layer formation was found around the different bed particles. Instead, the ash forming matter were found as individual ash sticky (partial melted) particles in the bed. The bed material mineralogical composition had no influence of the agglomeration process because of the non layer formation propensities of the used silicon rich fuels.

  8. Evaluation of sanitary impact of urban air pollution. Agglomeration of Bordeaux impact at short and long term; Evaluation de l'impact sanitaire de la pollution atmospherique urbaine. Agglomeration de Bordeaux impact a cour et long terme

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-06-15

    A health impact assessment of air pollution based on the I.n.V.S. guidelines has been conducted in Bordeaux area. Atmospheric pollution indicators analyzed were ozone, nitrogen dioxide and particles having diameter below 10 {mu}m. Short term impact of atmospheric pollution has been estimated in term of mortality (total, cardiovascular and respiratory mortality) and hospital admissions (for respiratory, cardiovascular and cardiac reasons) attributable to air pollution. Long-term impact was also assessed by the number of deaths due to atmospheric pollution. The study has been carried out in 22 cities homogeneously exposed belonging to Bordeaux agglomeration, representing a study population of 604,238 inhabitants. In 2001, the atmospheric pollution has directly been responsible in the studied area of 56 anticipated deaths, including half for cardiovascular reasons and 7 for respiratory reasons. Regarding morbidity, 29 hospital admissions for respiratory disease were attributable to air pollution in 2002, including two-thirds among elderly people (aged 65 years and over). Further more, 81 hospitalizations for cardiovascular diseases that occurred in 2002 were attributable to air pollution, including 27 for cardiac reasons. A decrease by 25% of the pollutants could have allowed avoiding about half of the premature deaths and hospital intakes attributable to air pollution. Concerning long term effects, about 200 annual deaths are attributable to chronic exposure to air pollution, and a decrease by 5{mu}g/m{sup 3} of the annual mean of PM{sub 10} could allow avoiding half of these deaths. The results have to be interpreted with care because of the limits of the H.I.A. method. However, they show that air pollution has a non negligible impact even in a city like Bordeaux where target values are mostly respected. They also show that reducing air pollution can have a significant impact in term of mortality and morbidity. However, a policy of atmospheric pollution reduction

  9. Evaluation of sanitary impact of urban air pollution. Agglomeration of Pau impact at short and long term; Evaluation de l'impact sanitaire de la pollution atmospherique urbaine. Agglomeration de Pau impact a cour et long terme

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    A health impact assessment of air pollution based on the I.n.V.S. guidelines has been conducted in Pau according to the regional Plan for the quality of air in the region of Aquitaine. Short-term effects of pollutants on morbidity (hospital admissions in 2002) and mortality (deaths in 2001) have been estimated. Long-term effect on mortality was also assessed. This study is based on the four standardised steps of health risk assessment. It has been carried out in twenty-nine cities homogeneously exposed, belonging to Pau agglomeration, i.e. a study population of about 150,000 inhabitants. Atmospheric pollution indicators analysed are ozone, nitrogen dioxide, and particles having diameter below 10 {mu}m. Short-term impact of atmospheric pollution has been estimated in term of mortality (total, cardiovascular and respiratory mortality) and on hospital intakes (for respiratory, cardiovascular and cardiac reasons) attributable to air pollution. Long term impact was also assessed by the number of deaths due to atmospheric pollution. In 2001, the atmospheric pollution has directly been responsible in the studied area for 17 anticipated deaths, including 7 for cardiovascular reason and 2 for respiratory reason. Concerning morbidity, it generated 20 hospital admissions for cardiovascular reason in 2002, 11 for cardiac reason, and 7 for respiratory reason among elderly people. Regarding long-term health gains, an annually decrease according to the European standards levels of 2010 could allow avoiding 12 deaths per year, and a decrease by 30% of the pollutants could allow avoiding 33 premature deaths per year. This study shows that, even if the relative risks associated to air pollution are quite low, the number of attributable cases is non negligible since everyone is exposed to air pollution. It also shows that a policy of atmospheric pollution reduction only based on not exceeding the standard levels would not have the expected benefits on the public health point of view

  10. Skills, Agglomeration and Segmentation

    OpenAIRE

    Tomoya Mori; Alessandro Turrini

    2000-01-01

    We investigate the role of skill heterogeneity in explaining location patterns induced by pecuniary externalities (Krugman (1991)). In our setting, sellers with higher skills perform better in the marketplace, and their sales are larger. Selling to distant locations leads to lower sales because of both (pecuniary) transport costs and communication costs that reduce the perceived quality of goods. A symmetry-breaking result is obtained: symmetric configurations cannot be stable, and regional i...

  11. Nanoparticle agglomerates in magnetoliposomes

    International Nuclear Information System (INIS)

    Magnetoliposomes consist of vesicles composed of a phospholipid membrane encapsulating magnetic nanoparticles. These systems have several important applications, such as in MRI contrast agents, drug and gene carriers, and cancer treatment devices. For all of these applications, controlling the number of encapsulated magnetic nanoparticles is a key issue. In this work, we used a magneto-optical technique to obtain information about the efficiency of encapsulation, the number of nanoparticles encapsulated per liposome and also about the formation of the nanoparticle structures. The parameters studied included the effect of the duration of sonication, the presence of cholesterol in the liposome membrane, as well as time-related stability. For the liposomal vesicles prepared in this work, we found between 35 and 300 nanoparticles encapsulated per liposome, depending on the experimental conditions, consisting of small linear chains of nanoparticles, basically trimers and tetramers. The methodology developed might be useful for the investigation and improvement of the properties of several magnetic nanocarrier systems.

  12. Agglomeration and aid

    NARCIS (Netherlands)

    S. Brakman (Steven); J.H. Garretsen (Harry); J.G.M. van Marrewijk (Charles)

    2007-01-01

    textabstractA key issue in development economics is the explanation of core-periphery patterns around the world. Combining this issue with that of analyzing unilateral transfers (e.g. foreign aid) points in the direction of the use of New Economic Geography (NEG) models which, so far, has not been d

  13. 中国都市区和大城市群的界定——兼论大城市群在区域经济发展中的作用%Definition of Chinese Metropolitan Areas and Large Urban Agglomerations: Role of Large Urban Agglomerations in Regional Development

    Institute of Scientific and Technical Information of China (English)

    宁越敏

    2011-01-01

    大城市群正在成为城市化空间组织的主要形态,构成国家经济发展的重心.改革开放以来,中国重新纳入到世界经济体系之中,工业化与城市化加速发展推动了城市群规模壮大与能级提升.本文首先采用"五普"资料对大都市区进行界定,以大都市区为基本组成单元界定中国的大城市群,分析了中国13个大城市群的空间分布特征及在区域经济发展中的引领作用.%The large urban agglomerations are the main form of spatial organization of urbanization, and they have become the powerful engine of national economic development. Since reform and opening-up, China has reintegrated into the world economic system, and both industrialization and urbanization have accelerated the enlargement of scale of large urban agglomerations and upgraded their function level. This paper firstly defines the concept of Chinese metropolitan areas based on the data attained from the fifth national census, and distinguishes the three types of Chinese metropolitan areas. In 2000, China had a total of 117 metropolitan areas, of which twenty-six areas had a population of 2 million or more. Then, the paper defines the concept of large urban agglomerations in China, and summarizes the basic features of 13 large urban agglomerations. This paper uses the metropolitan area as the basic unit to define the concept of large urban agglomerations in China, then analyzes their spatial distribution and roles in regional development. And the author thinks that Chinese large urban agglomerations play important roles as the centre of gravity of the national economy and the growth engines in regional development.

  14. Research into specific nature of pollutants migration within subsurface space of large scale industrial and urban agglomerations by isotope techniques

    International Nuclear Information System (INIS)

    During the study of the past accident groundwater radionuclide contamination of main aquifers at the area of Kiev Industrial and Urban Agglomeration (KIUA), measurable amounts of 137Cs and 90Sr had been determined on the relatively high depth. In the first stage of sampling more than 20 wells had been observed contained the trace amounts of short living 134Cs (Goudzenko, 1993). Further observations support the previous results for the 137Cs and 90Sr in the wells of municipal water supply system in the city of Kiev and suburbs. Maximal concentrations of 137Cs for the upper aquifer, located in the Quaternary deposits, reach up 50 odd mBq/l in 1992. The same figure for 90Sr was about 20 mBq/l . For deeper aquifers such as Neogene, Palaeogene, Cretaceous and Jurassic maximal concentration in the groundwater were some less, but in the same time, over 20 and 10 mBq/l respectively. Concentration of 3H in these water bearing sets reach up several Bq/l. So deep and quick penetration of radionuclides from the daylight surface to the groundwater compels to search for suitable pathways and mechanisms of their movement. Despite of concentrations of decay products in the groundwater of KIUA today are far from the permissible levels, the investigation of this phenomenon seems to be very important. A lot of possible contaminants, generating in IUAs, may move through the unsaturated zone by the same mechanisms as radionuclides. Measurable amounts of 137Cs and 90Sr had been determined too sometimes in the soils and rocks of Kiev on the depth up to 300 m. The Chernobyl origin of these nuclides, as mentioned above, had been confirmed during the first stage of investigation. Simultaneously with going on monitoring of 137Cs and 90Sr in the water intake wells of municipal water supply system, the range of marl samples had been collected from the constructing metro tunnels, water, sediments and sinters from drainage adits, built on the slopes of Dnieper valley and its little tributaries

  15. Agglomerated nanoparticles of hydrous Ce(IV) + Zr(IV) mixed oxide: Preparation, characterization and physicochemical aspects on fluoride adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Abir; Chakrabarti, Sharadindra; Biswas, Krishna; Ghosh, Uday Chand, E-mail: ucghosh@yahoo.co.in

    2014-07-01

    Hydrous Ce(IV)–Zr(IV) oxide (Ce/Zr ~ 1:1, mol/mol) (HCZMO) prepared by simple chemical precipitation was nanoparticles (60–70 nm) agglomerate with irregular surface morphology. The BET surface area, pore volume and pHzpc were estimated to be 185.04 m² g⁻¹, 0.1219 cm³ g⁻¹ and 5.8 (±0.2), respectively. Investigation of fluoride adsorption over HCZMO from its aqueous phase at an optimized pH ~ 6.0 showed that the adsorption kinetics and equilibrium data described, respectively, the pseudo-second order equation (R² = 0.98–0.99) and the Langmuir isotherm (R² > 0.99) very well. Values of the computed Arrhenius activation energy, Ea (1.16 kJ mol⁻¹), Langmuir monolayer capacity, θ (19.5 mg g⁻¹), D–R adsorption energy, ED–R (15.05 kJ mol⁻¹) and isosteric heat of reaction, ΔHr (0.518 kJ mol⁻¹) suggested that the fluoride has high affinity for homogeneous HCZMO surface for adsorption. Evidences appeared from the equal distribution co-efficient values and too well Langmuir isotherm fit. The fluoride adsorption reactions at 298–313 K with HCZMO were spontaneous (ΔG⁰ = negative) despite endothermic nature (ΔH⁰, kJ mol⁻¹ = +3.53, +4.04), owing to the increase of entropy (ΔS⁰, J mol⁻¹ K⁻¹ = +12.4, 13.8). More than 95% fluoride was released from F⁻-HCZMO (24.8 mg F⁻ g⁻¹) by 1.0 M NaOH, confirming the ion-exchange adsorption mechanism inclining to chemisorption. 1 g HCZMO per liter of a groundwater (F⁻: 4.40 mg L⁻¹) can reduce fluoride level below 1.5 mg L⁻¹ in batch treatment.

  16. FDI产业空间自相关与空间集聚——再论为什么FDI不集聚西部%Spatial Dependence and Agglomeration of FDI industries: the Re-examination of Why FDI does not Agglomeration in Western China

    Institute of Scientific and Technical Information of China (English)

    罗宏翔; 赵果庆

    2012-01-01

    The spatial dependence of FDI has been confirmed by more and more studies, but most of them neg- lected the dependence of FDI industries. With the data of 2003 - 2008, we divide China's FDI industries into four categories, i.e. mining ( B-type ), low-ended manufacturing ( C 1 -type) , high-ended manufacturing ( Ca-type) and u- tilities(D-type) industries and test empirically their respective spatial correlation and agglomeration one by one. The results indicate that from the perspective of industry distribution, most FDI industries belong to C2-type in- dustries( over 50% ), while over 40% of the FDI industries belong to Cl-type and less than 4% belong to B and D- type. From the perspective of spatial contribution, the majority of FDI agglomerated in eastern regions and only a small proportion of FDI agglomerated in central and western regions. We did a statistics test for the four types of FDI industries to test glomeration in 2003 lation agglomeration and 2008. The results show that B and D-type FDI their respective spatial correlation and ag- industries belong to non-spatial auto-corre- and C1 and C2-type belong to spatial correlation agglomeration. Since the CI and C2-type are four-order spatially correlated, we then divided C1 and C2-type FDI industries in- to four groups. The first quadrant is High-High group, which is a high FDI regions agglomerated with four nearly high FDI regions. The second quadrant is Low-High group, which is a low FDI regions agglomerated with four near- ly high FDI regions. The third quadrant is Low-Low group, which is a low FDI regions agglomerated with four near- ly low FDI regions. The forth quadrant is High-Low group, which is a high FDI regions agglomerated with four nearly low FDI regions. The H-H and H-L are two important groups. In 2003, 80. 69% of Cl-type FDI industries are H-H or H-L groups while in 2008 the ratio is 82.35%. In 2008, 88.81% of C2 type FDI industries are H-H or H-L groups while in 2008

  17. Observational Data Analysis and Numerical Model Assessment of the Seafloor Interaction and Mobility of Sand and Weathered Oil Agglomerates (Surface Residual Balls) in the Surf Zone

    Science.gov (United States)

    Dalyander, S.; Long, J.; Plant, N. G.; Penko, A.; Calantoni, J.; Thompson, D.; Mclaughlin, M. K.

    2014-12-01

    When weathered oil is transported ashore, such as during the Deepwater Horizon oil spill, it can mix with suspended sediment in the surf zone to create heavier-than-water sand and oil agglomerates in the form of mats several centimeters thick and tens of meters long. Broken off pieces of these mats and smaller agglomerates formed in situ (called Surface Residual Balls, SRBs) can cause beach re-oiling months to years after the initial spill. The physical dynamics of these SRBs in the nearshore, where they are larger (cm-scale) and less dense than natural sediment, are poorly understood. In the current study, SRB mobility and seafloor interaction is investigated through a combination of laboratory and field experiments with pseudo-SRBs developed to be physically stable proxies for genuine agglomerates. Formulations for mobility prediction based on comparing estimated shear stress to the critical Shields and modified Shields parameters developed for mixed sediment beds are assessed against observations. Processes such as burial, exhumation, and interaction with bedforms (e.g., migrating ripples) are also explored. The observations suggest that incipient motion estimates based on a modified Shields parameter have some skill in predicting SRB movement, but that other forcing mechanisms such as pressure gradients may be important under some conditions. Additionally, burial and exhumation due to the relatively high mobility of sand grains are confirmed as key processes controlling SRB dynamics in the surf zone. This work has broad implications for understanding surf zone sediment transport at the short timescale associated with mobilizing sand grains and SRBs as well as at the longer timescales associated with net transport patterns, sediment budgets, and bed elevation changes.

  18. Use of flux welding slag of the Mn-O-SiO2 system for the obtaining of a new alloyed agglomerated flux

    International Nuclear Information System (INIS)

    This paper deals with the use of welding slags of the MnO-SiO2 system fluxes, coming from the recovering by means of the submerged arc welding in the manufacturing of agglomerated fluxes for surfacing with the same propose. the composition of the matrix is studied by means of an experimental design in a restricted area of the Mc Lean Anderson kind, the technological behaviour of the different mixtures is checked, and the results of the best types that have alloy charges included are analysed by a characterization of the weld. (Author) 20 refs

  19. Detection of selected pathogens in ticks collected from cats and dogs in the Wrocław Agglomeration, South-West Poland

    OpenAIRE

    Król, Nina; Obiegala, Anna; Pfeffer, Martin; Lonc, Elżbieta; Kiewra, Dorota

    2016-01-01

    Background Tick-borne infections are no longer confined to rural areas, they are documented with increasing frequency in urban settlements across the world. They are known to cause diseases in humans as well as in their companion animals. Methods During a period of 2 years, from January 2013 until December 2014, ticks were collected from dogs and cats in 18 veterinary clinics in the Wrocław Agglomeration, Poland. In total, 1455 ticks were found on 931 pets: 760 domestic dogs and 171 cats. For...

  20. Sprawność fizyczna osób w wieku emerytalnym z aglomeracji miejskiej = Fitness of retirement age with urban agglomeration

    OpenAIRE

    Ratkowski, Wojciech; Grabowska-Skorb, Paulina; Bzdawski, Maciej; Napierała, Marek; Pezala, Małgorzata; Zukow, Walery

    2015-01-01

    Ratkowski Wojciech, Grabowska-Skorb Paulina, Bzdawski Maciej, Napierała Marek, Pezala Małgorzata, Zukow Walery. Sprawność fizyczna osób w wieku emerytalnym z aglomeracji miejskiej = Fitness of retirement age with urban agglomeration. Journal of Education, Health and Sport. 2015;5(4):177-194. ISSN 2391-8306. DOI: 10.5281/zenodo.16726 http://ojs.ukw.edu.pl/index.php/johs/article/view/2015%3B5%284%29%3A177-194 https://pbn.nauka.gov.pl/works/554168 http://dx.doi.org/10.5281/zen...

  1. Agglomeration and reaction characteristics of various coal chars in fluidized-bed coal gasifier; Ryudoso sekitan gas ka ronai deno sekitan no gyoshu tokusei to hanno tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Uemiya, S.; Aoki, K.; Mori, S.; Kojima, T. [Seikei University, Tokyo (Japan). Faculty of Engineering

    1996-10-28

    With relation to the coals delivered as common samples in the coal fundamental technology development project, an experimental study was conducted on agglomeration characteristics and reaction characteristics in the fluidized-bed coal gasifier. For the experiment, used was a fluidized bed gasifier inserted with a cone-shape dispersion plate with a nozzle in the center. After raising the temperature of the gasifier up to 773K, gasification was conducted sending to the gasifier air from the nozzle and steam from the dispersion plate. The mean particle diameter and gas concentration of chars were measured till the temperature reaches 1373K. As a result of the experiment, it was confirmed that the carbon conversion ratio increases with a decrease in coalification degree of the coal. Moreover, influence of the coal kind was markedly observed at the grid zone of the lower part of the bed, and it was clarified that the lower carbon content ratio the coal kind has, the faster the speed of CO formation and water gasification get. The agglomeration temperature of charcoal which is a product of the condensate is lower by as many as several hundred K than the point of softening, and it was considered to be necessary to study the relation with the temperature distribution in the bed. 3 refs., 3 figs., 1 tab.

  2. Assessment of agglomeration, co-sedimentation and trophic transfer of titanium dioxide nanoparticles in a laboratory-scale predator-prey model system

    Science.gov (United States)

    Gupta, Govind Sharan; Kumar, Ashutosh; Shanker, Rishi; Dhawan, Alok

    2016-01-01

    Nano titanium dioxide (nTiO2) is the most abundantly released engineered nanomaterial (ENM) in aquatic environments. Therefore, it is prudent to assess its fate and its effects on lower trophic-level organisms in the aquatic food chain. A predator-and-prey-based laboratory microcosm was established using Paramecium caudatum and Escherichia coli to evaluate the effects of nTiO2. The surface interaction of nTiO2 with E. coli significantly increased after the addition of Paramecium into the microcosm. This interaction favoured the hetero-agglomeration and co-sedimentation of nTiO2. The extent of nTiO2 agglomeration under experimental conditions was as follows: combined E. coli and Paramecium > Paramecium only > E. coli only > without E. coli or Paramecium. An increase in nTiO2 internalisation in Paramecium cells was also observed in the presence or absence of E. coli cells. These interactions and nTiO2 internalisation in Paramecium cells induced statistically significant (p < 0.05) effects on growth and the bacterial ingestion rate at 24 h. These findings provide new insights into the fate of nTiO2 in the presence of bacterial-ciliate interactions in the aquatic environment. PMID:27530102

  3. 3D RVE models able to capture and quantify the dispersion, agglomeration and orientation state of CNT in CNT/PP nanocomposites

    Science.gov (United States)

    Bhuiyan, Md; Pucha, Raghuram; Kalaitzidou, Kyriaki

    2016-02-01

    The focus of this study is to investigate the capabilities of 3D RVE models in predicting the tensile modulus of carbon nanotube polypropylene (CNT/PP) composites which differ slightly in the dispersion, agglomeration and orientation states of CNT within the PP matrix. The composites are made using melt mixing followed by either injection molding or melt spinning of fibers. The dispersion, agglomeration and orientation of CNT within the PP are experimentally altered by using a surfactant and by forcing the molten material to flow through a narrow orifice (melt spinning) that promotes alignment of CNT along the flow/drawing direction. An elaborate image analysis technique is used to quantify the CNT characteristics in terms of probability distribution functions (PDF). The PDF are then introduced to the 3D RVE models which also account for the CNT-PP interfacial interactions. It is concluded that the 3D RVE models can accurately distinguish among the different cases (dispersion, distribution, geometry and alignment of CNT) as the predicted tensile modulus is in good agreement with the experimentally determined one.

  4. 3D RVE models able to capture and quantify the dispersion, agglomeration and orientation state of CNT in CNT/PP nanocomposites

    Directory of Open Access Journals (Sweden)

    Md Atiqur Bhuiyan

    2016-02-01

    Full Text Available The focus of this study is to investigate the capabilities of 3D RVE models in predicting the tensile modulus of carbon nanotube polypropylene (CNT/PP composites which differ slightly in the dispersion, agglomeration and orientation states of CNT within the PP matrix. The composites are made using melt mixing followed by either injection molding or melt spinning of fibers. The dispersion, agglomeration and orientation of CNT within the PP are experimentally altered by using a surfactant and by forcing the molten material to flow through a narrow orifice (melt spinning that promotes alignment of CNT along the flow/drawing direction. An elaborate image analysis technique is used to quantify the CNT characteristics in terms of probability distribution functions (PDF. The PDF are then introduced to the 3D RVE models which also account for the CNT-PP interfacial interactions. It is concluded that the 3D RVE models can accurately distinguish among the different cases (dispersion, distribution, geometry and alignment of CNT as the predicted tensile modulus is in good agreement with the experimentally determined one.

  5. Assessment of agglomeration, co-sedimentation and trophic transfer of titanium dioxide nanoparticles in a laboratory-scale predator-prey model system.

    Science.gov (United States)

    Gupta, Govind Sharan; Kumar, Ashutosh; Shanker, Rishi; Dhawan, Alok

    2016-01-01

    Nano titanium dioxide (nTiO2) is the most abundantly released engineered nanomaterial (ENM) in aquatic environments. Therefore, it is prudent to assess its fate and its effects on lower trophic-level organisms in the aquatic food chain. A predator-and-prey-based laboratory microcosm was established using Paramecium caudatum and Escherichia coli to evaluate the effects of nTiO2. The surface interaction of nTiO2 with E. coli significantly increased after the addition of Paramecium into the microcosm. This interaction favoured the hetero-agglomeration and co-sedimentation of nTiO2. The extent of nTiO2 agglomeration under experimental conditions was as follows: combined E. coli and Paramecium > Paramecium only > E. coli only > without E. coli or Paramecium. An increase in nTiO2 internalisation in Paramecium cells was also observed in the presence or absence of E. coli cells. These interactions and nTiO2 internalisation in Paramecium cells induced statistically significant (p < 0.05) effects on growth and the bacterial ingestion rate at 24 h. These findings provide new insights into the fate of nTiO2 in the presence of bacterial-ciliate interactions in the aquatic environment. PMID:27530102

  6. Alimento para fins especiais: ingredientes, elaboração e aglomeração Food for special needs: ingredients, development and agglomeration

    Directory of Open Access Journals (Sweden)

    Luciana Azevedo

    2011-04-01

    Full Text Available OBJETIVO: Desenvolver uma dieta enteral nutricionalmente completa, com condições ajustadas de aglomeração, visando contemplar as características físicas e químicas desejadas para esse alimento especial. MÉTODOS: Como ingredientes foram utilizados maltodextrina, óleo de canola, triglicerídios de cadeia média, goma acácia, inulina e frutooligossacarídeos, proteínas do soro de leite, isolado proteico de soja, vitaminas e minerais. Após os ajustes das quantidades e proporções dos ingredientes, a formulação foi aglomerada e submetida às análises de composição centesimal, molhabilidade, densidade aparente, atividade de água, viscosidade e cor. RESULTADOS: Obteve-se uma fórmula contendo 1kcal.mL-1, normoproteica (3,9g.100mL-1 e normolipídica (3,9g.100mL-1. Após a aglomeração da dieta, observaram-se os seguintes resultados: molhabilidade de 0,262g.s-1, densidade aparente de 0,317g.cm-3e atividade de água de 0,393. A análise de cor indicou redução da luminosidade e aumento dos parâmetros de cor a*e b*, apresentando leve variação para o vermelho e forte presença do amarelo. CONCLUSÃO: Os ingredientes empregados, e suas respectivas proporções, bem como o processo de aglomeração, possibilitaram a obtenção de um alimento para fins especiais com propriedades bioativas. O processo de aglomeração possibilitou uma dieta de fácil reconstituição e utilização através de sondas, facilitando a infusão e, consequentemente, a diminuição de intercorrências.OBJECTIVE: This study aimed to develop a nutritionally complete enteral diet, with adjusted agglomeration conditions, and determine the physical and chemical characteristics required by this special food. METHODS: The ingredients were maltodextrin, canola oil, medium-chain triglycerides, acacia gum, inulin, fructooligosaccharides, milk whey protein, soy protein isolate, vitamins and minerals. After the quantities and proportions of the ingredients were adjusted

  7. 皖江城市带区域支柱性产业空间集聚水平及特征研究%Research on Spatial Agglomeration Level and Character of Regional Pillar Industries in Wanjiang City Belt

    Institute of Scientific and Technical Information of China (English)

    赵惠芳; 王伟; 叶成

    2014-01-01

    Based on the selected regional pillar industries in Wanjiang City Belt ,this paper measures the spatial agglomeration level of these pillar industries by industrial agglomeration index ,agglomera-tion elasticity coefficient ,market concentration rate and Krugman regional division index ,then analy-zes the spatial agglomeration degree ,agglomeration elasticity and regional division of labor from two dimensions of industry and city .T he results indicate that during 2003-2011 ,the overall agglomera-tion degree of pillar industries in Wanjiang City Belt is high ,but there are significant differences in va-rious industries ;both high-tech industries and capital intensive industries within low-tech industries appear spatial agglomeration with high degree ;the economic growth of different industries shows dif-ferent sensitivity to the industrial agglomeration changes .Hefei and Wuhu are the core layer and the other cities are the external layer in the religion ,thus forming a binary spatial distribution pattern ;the division of labor based on specialization in each city is quite reasonable .%选定皖江城市带区域支柱性产业,利用产业空间集聚指数、集聚弹性系数、市场集中率和克鲁格曼区域分工指数对其空间集聚水平进行了综合测度,基于行业和城市的双维度视角针对空间集聚程度、集聚弹性及区域分工等展开探究。结果表明:2003-2011年,皖江城市带区域支柱性产业整体集聚程度较高,但各行业存在明显差异;高技术类别行业、中低技术类别中的资本密集型行业均呈现出高度空间集聚;不同行业的工业经济增长对产业集聚度变动的敏感性不同。区域内基本形成了以合肥、芜湖为核心层,其他城市为外围层的“核心-外围”二元空间分布模式;各城市间的专业化分工较为合理。

  8. Quantifying the Radiation Effect of Industry in Urban Agglomerations%城市群内城市产业辐射效应测算

    Institute of Scientific and Technical Information of China (English)

    李俊玮; 常远; 高菠阳

    2015-01-01

    As the key subject of the 12th five-year development plan,the importance of urban agglomerations in national economy development is rising. This study established an industry radiation force model and radiation fault zones model to quantify the radiation force and area of specific industry of core cities in urban agglomerations. Based on data from 2000 to 2012,the study measured the real estate radiation force and range of Beijing to its surrounding cities in Beijing-Tianjin-Hebei. Results show that the fault zone is shrinking and is affected by five factors,including the mechanisms of urban agglomerations,macro-economy operation, industrial characteristics,government policies,and the supply and demand sides of real estate market. This study provides method to quantify the industry radiation force and scope and facilitates urban government’s policy making for industrial development.%作为“十二五”规划重点发展对象,城市群在我国经济发展中占据重要地位。通过构建城市产业辐射力模型和城市产业辐射断裂带模型,测算城市群中核心城市特定产业的辐射能力与范围,并利用2000~2012年数据实证测算京津冀城市群中北京市对周边地区房地产业的辐射影响。研究结果表明产业辐射断裂带呈微缩趋势,影响因素源于城市群机理、宏观经济背景、行业特征、政府政策、供需双方行为5个方面。该研究为测量城市群内城市特定产业的辐射力强度与范围提供了理论方法;有助于政府部门全面掌握城市产业辐射力表现,为科学制定城市产业发展规划提供参考与依据。

  9. Impact of pyranose oxidase from Trametes multicolor, glucose oxidase from Aspergillus niger and hydrogen peroxide on protein agglomeration in wheat flour gluten-starch separation.

    Science.gov (United States)

    Decamps, Karolien; Gryp, Glenn; Joye, Iris J; Courtin, Christophe M; Delcour, Jan A

    2014-04-01

    The impact of pyranose oxidase (P₂O), glucose oxidase (GO) and H₂O₂ on gluten agglomeration during wheat flour gluten-starch separation was studied. Analysis of gluten aggregate sizes in batter formed from wheat flour dough revealed that increasing levels of oxidising agents gradually decreased the tendency of gluten proteins to form large gluten aggregates. Low enzyme levels increased arabinoxylan (AX) and starch retention on the sieves, due to physical incorporation of AX and starch in the gluten aggregates. Higher enzyme levels increased retention of starch and AX on the smaller and larger sieves, respectively. Extensive oxidation leads to physical incorporation of AX and starch granules in the small gluten aggregates. AX is also crosslinked and hence more easily retained on the top sieves. Our results confirm that the size of gluten aggregates and the level of AX crosslinking and AX and starch incorporation in gluten proteins depend on the concentration of H₂O₂. PMID:24262551

  10. Influence of the Ratio of Ethanol to Water on the Agglomeration of Al2O3/Y2O3-ZrO2 Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Li Xiuhua; Du Juanjuan; Zhu Liying; Cheng Huijie; Wang Lingwei

    2007-01-01

    A method of heating ethanol-aqueous salt solution combined with co-precipitation was used to synthesize Al2O3/ZrO2 nanoparticles. The analysis of DSC and XRD revealed that the transformation temperature from amorphous to crystal phase was about 850℃. The grain size was increased with the raising of calcine temperature. The alcohol-water ratio did not affect the formation of main crystal phases, but affected the agglomeration of nanoparticles based on the results of TEM. When alcohol-water ratio was 5:1, the dispersion of nanoparticles was good. When there was not alcohol, the dispersion of nanoparticles was poor because there was only pure co-precipitation reaction and the speed of co-precipitation reaction was too high to have enough time of PEG. dispersing particles.

  11. Structural and electrochemical properties of 20-micron Li(Co1-xLix)O2-δ (x>0) agglomerates with layered structures: Identification of tetravalent cobalt

    Science.gov (United States)

    Mishima, Y.; Hojo, T.; Nishio, T.; Kajiyama, A.; Moriyoshi, C.; Kuroiwa, Y.

    2015-12-01

    The increasing demand for the high energy density of lithium-ion batteries gives rise to the development of larger particle sizes of the active electrode materials. 20 μm-sized Li(Co1-xLix)O2-δ agglomerates are synthesized via solid-state reactions with different nominal compositions (Li/Co=1.00, 1.02, and 1.05) at 1000 °C for 5 h in ambient air while suppressing the lithium vaporization. Careful inductively coupled plasma and iodometric measurements indicate the existence of tetravalent cobalt in the solid solutions (x>0). The decreasing ideal capacity with the increasing x value could cause the resulting initial capacities at under a quasi-equilibrium condition. The defect structure is also discussed in terms of the structural parameters calculated from Rietveld refinements of the high-energy synchrotron-radiation powder-diffraction data.

  12. Identification of urban agglomerations according to Directive 91/271/EC on urban wastewaters treatment: methodological proposal and application to the territory of Veneto Region

    International Nuclear Information System (INIS)

    The study discusses the problem of the identification and definition of the agglomerations for the Veneto regional territory according to Directive 91/271/EC to guarantee an adequate level of treatment for urban wastewaters and the achievement of the quality objectives for water bodies. The followed methodology, taking account of the existing planning in the water service sector, has been based on available data from ISTAT (National Statistical Institute) relative to the census sections, on the Regional Water Restoration Plan (PRRA), plan to be substituted with the Water Protection Plan, on the predictions of Water Service Plans prepared by each Water Authority (AATO and on the detailed indications of the same AATO. Moreover some considerations on the obtained results are presented and discussed.

  13. SPATIAL LINKAGE PATTERN OF TOURISM ECONOMY IN THE WANJIANG URBAN AGGLOMERATION%皖江城市群旅游经济空间联系格局

    Institute of Scientific and Technical Information of China (English)

    沈惊宏; 陆玉麒; 周玉翠; 尹贻梅

    2012-01-01

    在皖江城市群作为承接长三角产业转移示范区背景下及区域交通网络化、区域旅游一体化发展的新形式下,对皖江城市群旅游经济联系和影响范围研究就显得必要。以该地区10城市的旅游经济联系为主线,以界定旅游中心节点、测算旅游经济联系量和场强模型为手段,构建皖江城市群旅游圈。研究表明:以合肥和芜湖为双核的皖江城市群大旅游圈,其内部分为3个次旅游经济圈,北部以合肥为中心,包括六安区域、滁州和含巢湖整个水面的大部分区域的合肥旅游圈;西南以安庆为中心、池州为副中心,含铜陵一部分地区的安庆旅游圈;东南以芜湖为中心、宣城为副中心,包括马鞍山和部分巢湖区域、部分铜陵区域的芜湖旅游圈。最后提出了3个旅游经济圈发展的旅游规划建议。%Under the Wanjiang Urban Agglomeration becoming demonstration zones of facilitating industrial transfer of the Yangtze River Delta, and the new situation of the regional transportation network and the integration of regional tourism development, it is a fundamental requirement to set up a new cooperation mechanism of tourism development and coordinate regional sustainable tourism development for tourism e- conomy in the Wanjiang Urban Agglomeration. Thus,it is necessary to study on tourism economic linkage and areas of influence in the Wanjiang Urban Agglomeration. Tourism economic linkage among the 10 cities was regarded as the main line of the thesis. The author defined tourism center node, calculated strength of tourism economic linkage and influence areas of field-strength, and constructed tourism circles of the Wanjiang Urban Agglomeration. The results showed that Wanjiang city group tourism circle centering on dualcore of Hefei and Wuhu was divided into three tourism economic circles. They were Hefei tourism circle centering on Hefei in the northern of it,including parts of

  14. Colloidal Instability Fosters Agglomeration of Subvisible Particles Created by Rupture of Gels of a Monoclonal Antibody Formed at Silicone Oil-Water Interfaces.

    Science.gov (United States)

    Mehta, Shyam B; Carpenter, John F; Randolph, Theodore W

    2016-08-01

    In this study, we investigated the effect of ionic strength (1.25-231 mM) on viscoelastic interfacial gels formed by a monoclonal antibody at silicone oil-water interfaces, and the formation of subvisible particles due to rupture of these gels. Rates of gel formation and their elastic moduli did not vary significantly with ionic strength. Likewise, during gel rupture no significant effects of ionic strength were observed on particle formation and aggregation as detected by microflow imaging, resonance mass measurement, and size exclusion chromatography. Subvisible particles formed by mechanical rupturing of the gels agglomerated over time, even during quiescent incubation, due to the colloidal instability of the particles. PMID:27422087

  15. How the guest molecules in nanoporous Zn(II) metal-organic framework can prevent agglomeration of ZnO nanoparticles

    International Nuclear Information System (INIS)

    The host and the apohost framework of [Zn2(BDC)2(H2O)2·(DMF)2]n (1·2H2O·2DMF), (BDC2−=benzene-1,4-dicarboxylate and DMF=N,N-Dimethylformamide), were synthesized and subsequently used for preparation of ZnO nanomaterials. With calcination of the host framework of 1·2H2O·2DMF, ZnO nanoparticles were obtained. By the same process on the apohost framework of 1, agglomerated nanoparticles of ZnO were formed. These nano-structures were characterized by X-ray powder diffraction (XRD) and Scanning electron microscopy (SEM). These results indicate that with removal of the guest DMF and coordinated H2O molecules from the one-dimensional channels of 1·2H2O·2DMF, the tendency of nanoparticles to agglomerate increases and the role of this MOF in preparation of ZnO nanoparticles from this precursor was reduced. - Graphical abstract: Nano-porous zinc(II) MOF with guest DMF and coordinated H2O molecules has been synthesized and characterized. The host and the apohost framework of it were used for preparation of ZnO nanomaterials. The role of these species in preparation of ZnO nanoparticles from the host framework is probably similar to the role of polymeric stabilizers in formation of nanoparticles. - Highlights: • Nanoparticles of ZnO were fabricated from nanoporous metal-organic framework. • The effect of guest DMF and coordinated H2O molecules on this process was studied. • The effect of them in formation nanoparticle is similar to polymeric stabilizers

  16. Evolution of fractal agglomeration behaviour of Ca/Sr doped nano-crystalline lanthanum chromites under sintering: a small angle neutron scattering investigation

    International Nuclear Information System (INIS)

    Full text: In present study, sintering behaviour of calcium doped lanthanum chromite (La0.7Ca0.3CrO3) (LCC) and strontium doped chromite (La0.8Sr0.2CrO3) (LSC) powders which is used as interconnect material for SOFC application, synthesized through a gel combustion route, have been studied. Fractal morphology in LCC and LSC powder aggregate has been investigated using small angle neutron scattering (SANS) technique for different sintering temperatures. A comparison of the evolution of mesoscopic structure has also been elucidated for the two materials at different sintering temperatures. X-ray diffraction experiments show the isostructural crystalline structure for both powders. Neutron scattering data reveal a fractal type correlation of building blocks in the as-formed powders. An increase in fractal dimension and a reduction in upper cutoff were found as sintering progresses indicating a compaction of agglomerates with increasing sintering temperature. At about 1200 deg C sintering temperature, the fractal characteristics morphology disappears almost completely. This is due to relatively faster diffusion mechanism at higher sintering temperatures and also because of better sinterability of the nano-particles compared to their bulk counterpart. Possibility of transient liquid phase sintering and phase transition assisted sintering process at higher sintering temperature may also be a possibility. Comparison of SANS profiles for LCC and LSC powders indicate that agglomerates in initial virgin powder of LSC are relatively more loose and larger in nature as compared to that of LCC. This reveals that the sintering efficiency of virgin powder of LCC is relatively easy than that of LSC in spite of their isothermal crystalline phase

  17. How the guest molecules in nanoporous Zn(II) metal-organic framework can prevent agglomeration of ZnO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Moeinian, Maryam; Akhbari, Kamran, E-mail: akhbari.k@khayam.ut.ac.ir

    2015-05-15

    The host and the apohost framework of [Zn{sub 2}(BDC){sub 2}(H{sub 2}O){sub 2}·(DMF){sub 2}]{sub n} (1·2H{sub 2}O·2DMF), (BDC{sup 2−}=benzene-1,4-dicarboxylate and DMF=N,N-Dimethylformamide), were synthesized and subsequently used for preparation of ZnO nanomaterials. With calcination of the host framework of 1·2H{sub 2}O·2DMF, ZnO nanoparticles were obtained. By the same process on the apohost framework of 1, agglomerated nanoparticles of ZnO were formed. These nano-structures were characterized by X-ray powder diffraction (XRD) and Scanning electron microscopy (SEM). These results indicate that with removal of the guest DMF and coordinated H{sub 2}O molecules from the one-dimensional channels of 1·2H{sub 2}O·2DMF, the tendency of nanoparticles to agglomerate increases and the role of this MOF in preparation of ZnO nanoparticles from this precursor was reduced. - Graphical abstract: Nano-porous zinc(II) MOF with guest DMF and coordinated H{sub 2}O molecules has been synthesized and characterized. The host and the apohost framework of it were used for preparation of ZnO nanomaterials. The role of these species in preparation of ZnO nanoparticles from the host framework is probably similar to the role of polymeric stabilizers in formation of nanoparticles. - Highlights: • Nanoparticles of ZnO were fabricated from nanoporous metal-organic framework. • The effect of guest DMF and coordinated H{sub 2}O molecules on this process was studied. • The effect of them in formation nanoparticle is similar to polymeric stabilizers.

  18. 大型城市群建筑中的公共空间合理性设计%Public Space Rationality Design of Large Urban Agglomeration

    Institute of Scientific and Technical Information of China (English)

    戴菲

    2015-01-01

    通过对大型城市群建筑的公共空间合理性设计,提高大型城市群建筑公共空间合理设计水平,提高建筑空间的利用率.在增大城市居民居住区的绿化率的同时,实现城市建筑的绿色节能,设计的空间利用方案采用多参量自回归分析方法,空间设计中考虑的影响因素如光照、温度、湿度、绿化植被等影响,分析了大型城市公共空间设计的评价指标,给出空间优化设计拟合模型,研究结果表明,采用该设计方案,大型城市群建筑公共空间得到合理利用,实现节能环保,利用效率最高,改善人居环境.%Through the reasonable design of public space in the large city group, improve the public space of large urban ag-glomeration design level, improve the utilization of building space. Increased urban residential district greening rate at the same time, to achieve the green energy saving of urban construction, design space utilization scheme using multi parameter regression analysis method, space design in consideration of the influence factors such as light, temperature, humidity, green vegetation effect, analyzes the assessment index of large urban public space design, gives the optimum design of space fitting model, results show that the design scheme, the large scale urban agglomeration in building public space get reasonable use, to achieve energy saving and environmental protection, has the highest efficiency, improve the living envi-ronment.

  19. Analysis on Ecological Footprint of the Urban Agglomeration in Pearl River Delta%珠三角城市群生态足迹分析

    Institute of Scientific and Technical Information of China (English)

    钟义; 程欢; 彭晓春; 白中炎; 董家华; 陈志良; 李泰儒; 洪鸿加

    2012-01-01

    [目的]计算和分析2009年殊三角城市群生态足迹.[方法]以珠三角9个市为研究区,运用生态足迹计算模型对2009年珠三角市生态足迹和生态安全进行计算,定量分析珠三角区域生态环境现状和可持续发展状况.[结果]珠三角城市群除了建筑用地和林地稍显生态盈余外,其他4种土地类型均处于生态赤字状态,特别是可耕地和化石燃料用地,存在明显的生态赤字.[结论]珠三角生物资源消费水平和能源消费水平较高,应采取多种措施减少生态赤字,以使得发展方式向更加可持续性的方向转变.%[Objective] The research aimed to calculate and analyze ecological footprint of the urban agglomeration in Pearl River Delta in 2009, [Method] 9 cities in Pearl River Delta as research zone, by using calculation model of the ecological footprint, ecological footprint and security of the urban agglomeration in Pearl River Delta were calculated. Current situation and sustainable development condition of the ecological environment in Pearl River Delta were quantitatively analyzed. [Result] Except construction land and forest land, other 4 kinds of lands were all in ecological deficit statuses in Pearl River Delta. Especially arable land and fossil fuel land had obvious ecological deficit. [Conclusion] Biological resource consumption level and energy consumption level in Pearl River Delta were higher. We ought to take a variety of measures to reduce ecological deficit to make development manner turn toward sustainable direction.

  20. 中国城市群形成发育的政策保障机制与对策建议%Urban Agglomerations Formation and Development in China: Policy Guarantee Mechanism, Countermeasures and Suggestions

    Institute of Scientific and Technical Information of China (English)

    方创琳; 张舰

    2011-01-01

    Urban agglomeration with the most energies and potential, is a core district in China' s economic development pattern in the future, and is the key development zone and the optimized development zone in Major Function Oriented Zoning in China. Additionally, it is also the important direction for future urban development and acts as strategic support, growth pole and core node in national pattern of productivity location. According to some new characteristics and problems existing in the process of China' s urban agglomeration formation and development, this paper constructs organization and coordination guarantee mechanism (OCGM) , public finance guarantee mechanism ( PFCM), laws and regulations guarantee mechanism ( LRGM) and resources and environment guarantee mechanism (REGM) for urban agglomeration sustainable development respectively from four aspects of power, financial resources, legal force and ability. Furthermore, this paper puts forward some countermeasures and methods to speed up healthy urban agglomeration development, which includes the following: making certain state centralized management department and establishing state-level management committee of urban agglomeration coordinated development and cross-city coordinated organization for industrial development; constructing public finance mechanism and public finance reserve system; pushing the work of legislation for integrated development of urban agglomerations, constituting convention for cooperation of urban agglomerations and amending Urban and Rural Planning Act in which adds contents of urban agglomeration planning; putting forward Methods of Urban Agglomeration Planning Making, Examine and Approve, Regulations on Implementation and Management of Urban Agglomeration Planning and Technical Guidelines for Urban Agglomeration Planning, and establishing professional certified system to guide its scientific planning and strengthen capacity of resources and environment guarantee and sustainable