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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. Engineering of Piroxicam Agglomerates by Additives Using Wet Agglomeration Technique

    Directory of Open Access Journals (Sweden)

    Maryam Maghsoodi 1 *

    2016-12-01

    Full Text Available Background: Wet agglomeration is a method wherein the crystals of dispersion are held together in aggregates by small amount of a liquid acting as an intercrystal binder. In present study, in order to study the possible modification of agglomerate structure, low concentrations of additives (0.1-1% were added to binder liquid. Methods: Piroxicam agglomerates were produced by wet agglomeration method by three solvent systems including a good solvent (dimethylformamide or acetone, antisolvent (water and a binder liquid (ethylacetate or isopropylacetate. Span 80, talc, ethylcellulose and Eudragit RS in different concentrations were used as additives. The agglomerates were evaluated for production yield of agglomerates, size, friability and drug release properties. Results: The results showed that formation of agglomerates was possible in presence of span and talc. However, no agglomerates could be obtained with polymers tested (ethylcellulose and Eudragit RS. Talc increased agglomerate size, whereas the obtained agglomerates were more susceptible to breakup. However, using span as opposed to talc resulted in agglomerates with higher strength but smaller particle size. The dissolution tests showed that both additives adversely affected the dissolution rate of piroxicam from the agglomerates. Conclusion: Result of this study suggested that additives even in small amounts played a major role in agglomerate properties.

  3. 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...

  4. Spherical agglomeration of acetylsalicylic acid

    Directory of Open Access Journals (Sweden)

    Polowczyk Izabela

    2016-01-01

    Full Text Available In this paper spherical agglomeration of acetylsalicylic acid was described. In the first step, the system of good and poor solvents as well as bridging liquid was selected. As a result of a preliminary study, ethyl alcohol, water and carbon tetrachloride were used as the good solvent, poor one, and bridging liquid, respectively. Then, the amount of acetylsalicylic acid and the ratio of the solvents as well as the volume of the bridging liquid were examined. In the last step, the agglomeration conditions, such as mixing intensity and time, were investigated. The spherical agglomerates obtained under optimum conditions could be subjected to a tableting process afterwards.

  5. Agglomeration, Inequality and Economic Growth

    OpenAIRE

    David Castells; Vicente Royuela

    2014-01-01

    The impact of income inequality on economic growth is dependent on several factors, including the time horizon considered, the initial level of income and its initial distribution. Yet, as growth and inequality are also uneven across space, it is also pertinent to consider the effects of the geographical agglomeration of economic activity. Moreover, it would also seem pertinent to consider not just the levels of inequality and agglomeration, but also the changes they undergo (i.e., their with...

  6. 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.

  7. MTCI acoustic agglomeration particulate control

    Energy Technology Data Exchange (ETDEWEB)

    Chandran, R.R.; Mansour, M.N. [Manufacturing and Technology Conversion International, Inc., Columbia, MD (United States); Scaroni, A.W.; Koopmann, G.H. [Pennsylvania State Univ., University Park, PA (United States); Loth, J.L. [West Virginia Univ., Morgantown, WV (United States)

    1994-10-01

    The overall objective of this project is to demonstrate pulse combination induced acoustic enhancement of coal ash agglomeration and sulfur capture at conditions typical of direct coal-fired turbines and PFBC hot gas cleanup. MTCI has developed an advanced compact pulse combustor island for direct coal-firing in combustion gas turbines. This combustor island comprises a coal-fired pulse combustor, a combined ash agglomeration and sulfur capture chamber (CAASCC), and a hot cyclone. In the MTCI proprietary approach, the pulse combustion-induced high intensity sound waves improve sulfur capture efficiency and ash agglomeration. The resulting agglomerates allow the use of commercial cyclones and achieve very high particulate collection efficiency. In the MTCI proprietary approach, sorbent particles are injected into a gas stream subjected to an intense acoustic field. The acoustic field serves to improve sulfur capture efficiency by enhancing both gas film and intra-particle mass transfer rates. In addition, the sorbent particles act as dynamic filter foci, providing a high density of stagnant agglomerating centers for trapping the finer entrained (in the oscillating flow field) fly ash fractions. A team has been formed with MTCI as the prime contractor and Penn State University and West Virginia University as subcontractors to MTCI. MTCI is focusing on hardware development and system demonstration, PSU is investigating and modeling acoustic agglomeration and sulfur capture, and WVU is studying aerovalve fluid dynamics. Results are presented from all three studies.

  8. Coal Beneficiation by Gas Agglomeration

    Energy Technology Data Exchange (ETDEWEB)

    Thomas D. Wheelock; Meiyu Shen

    2000-03-15

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

  9. Urban agglomeration and CEO compensation

    OpenAIRE

    Francis, Bill; Hasan, Iftekhar; John, Kose; Waisman , Maya

    2012-01-01

    An underlying assumption in the executive compensation literature is that there is a national labor market for CEOs. The urban economics literature, however, documents higher ability among workers in large metropolitans, which results in a real and stable urban wage premium. In this paper, we investigate the link between the spatial clustering of firms in big, central cities (i.e., urban agglomeration) and the level and structure of CEO compensation. Using CEO compensation data for the period...

  10. Analyzing Agricultural Agglomeration in China

    Directory of Open Access Journals (Sweden)

    Erling Li

    2017-02-01

    Full Text Available There has been little scholarly research on Chinese agriculture’s geographic pattern of agglomeration and its evolutionary mechanisms, which are essential to sustainable development in China. By calculating the barycenter coordinates, the Gini coefficient, spatial autocorrelation and specialization indices for 11 crops during 1981–2012, we analyze the evolutionary pattern and mechanisms of agricultural agglomeration. We argue that the degree of spatial concentration of Chinese planting has been gradually increasing and that regional specialization and diversification have progressively been strengthened. Furthermore, Chinese crop production is moving from the eastern provinces to the central and western provinces. This is in contrast to Chinese manufacturing growth which has continued to be concentrated in the coastal and southeastern regions. In Northeast China, the Sanjiang and Songnen plains have become agricultural clustering regions, and the earlier domination of aquaculture and rice production in Southeast China has gradually decreased. In summary, this paper provides a political economy framework for understanding the regionalization of Chinese agriculture, focusing on the interaction among the objectives, decisionmaking behavior, path dependencies and spatial effects.

  11. Eco-spatial Structure of Urban Agglomeration

    Institute of Scientific and Technical Information of China (English)

    GUO Rongchao; MIAO Changhong; LI Xuexin; CHEN Deguang

    2007-01-01

    In terms of ecological theory, this paper makes a comprehensive analysis of the mutualism and coevolutionary mechanism between the eco-spatial structure and socio-economic development ofthe urban agglomeration,and maps out optimized modes of the eco-spatial structure of the urban agglomeration. The analysis is a case study of the urban agglomeration on different levels of global, national, provincial and local scales, on the basis of those conclusions are drawn: 1) Within the scope of the urban agglomeration, the cities should be reasonably sized and appropriately densified; the spatial combination of the urban agglomeration ought to be orderly, and its eco-spatial structure ought to be optimized and efficient; the relationship between the economic society and eco-spatial environment ought to be that of mutual benefit and co-evolution. 2) "The mode of corridor group network" is a certain trend evoked from the spatial structure of urban agglomeration. 3) The eco-spatial structure of urban agglomeration under "the mode of corridor group network" can further increase the environmental capacity of urban agglomeration, and is in favor of the harmonious relationship between man and nature.

  12. On the mechanism of agglomeration in suspension

    Directory of Open Access Journals (Sweden)

    Maryam Maghsoodi

    2012-06-01

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

  13. Engineering development of selective agglomeration. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1993-04-01

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

  14. Modeling of particle agglomeration in nanofluids

    Energy Technology Data Exchange (ETDEWEB)

    Krishna, K. Hari; Neti, S.; Oztekin, A. [Department of Mechanical Engineering and Mechanics, Lehigh University, 19W Memorial Dr, Bethlehem, Pennsylvania 18015 (United States); Mohapatra, S. [Dynalene Inc., 5250W Coplay Rd, Whitehall, Pennsylvania 18052 (United States)

    2015-03-07

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

  15. 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.

  16. Study of Metal Agglomeration and Combustion

    Science.gov (United States)

    1998-06-02

    of agglomerating particles in SL which, in turn, depends on the level of adhesion ( Fadh ) and aerodynamic (Faer) forces, discontinuity of SL and...influences the value of Fadh . On the whole, the FL properties might be determined by the ratio between Tign and the degradation temperature of...drop in Fadh contributes to decreasing the intensity of «inter-pocket» fusion and increasing the agglomerate dispersity. Hence, in spite of the

  17. 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

  18. Diffusion and reaction in microbead agglomerates.

    Science.gov (United States)

    Nunes Kirchner, Carolina; Träuble, Markus; Wittstock, Gunther

    2010-04-01

    Scanning electrochemical microscopy has been used to analyze the flux of p-aminonophenol (PAP) produced by agglomerates of polymeric microbeads modified with galactosidase as a model system for the bead-based heterogeneous immunoassays. With the use of mixtures of enzyme-modified and bare beads in defined ratio, agglomerates with different saturation levels of the enzyme modification were produced. The PAP flux depends on the intrinsic kinetics of the galactosidase, the local availability of the substrate p-aminophenyl-beta-D-galactopyranoside (PAPG), and the external mass transport conditions in the surrounding of the agglomerate and the internal mass transport within the bead agglomerate. The internal mass transport is influenced by the diffusional shielding of the modified beads by unmodified beads. SECM in combination with optical microscopy was used to determine experimentally the external flux. These data are in quantitative agreement with boundary element simulation considering the SECM microelectrode as an interacting probe and treating the Michaelis-Menten kinetics of the enzyme as nonlinear boundary conditions with two independent concentration variables [PAP] and [PAPG]. The PAPG concentration at the surface of the bead agglomerate was taken as a boundary condition for the analysis of the internal mass transport condition as a function of the enzyme saturation in the bead agglomerate. The results of this analysis are represented as PAP flux per contributing modified bead and the flux from freely suspended galactosidase-modified beads. These numbers are compared to the same number from the SECM experiments. It is shown that depending on the enzyme saturation level a different situation can arise where either beads located at the outer surface of the agglomerate dominate the contribution to the measured external flux or where the contribution of buried beads cannot be neglected for explaining the measured external flux.

  19. 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...

  20. AGGLOMERATIONS BENEFITS OF THE CULTURE ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Agata Ludwiczak

    2014-03-01

    Full Text Available This article is an attempt to find another interpretation of culture, an economic one as a significant local asset development conducive to the formation of agglomeration benefits through the mechanism of the presence of the creative class. The paper presented below provides a framework for thinking about this matter on the basis of economics. The article is a research hypothesis, yet nowhere formulated. Therefore, further empirical re-search is needed, particularly in relation to the villages of average size, indicating how culture is one factor contributing to the formation of the benefits of agglomeration.

  1. 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.

  2. Water migration mechanisms in amorphous powder material and related agglomeration

    NARCIS (Netherlands)

    Renzetti, S.; Voogt, J.A.; Oliver, L.; Meinders, M.B.J.

    2012-01-01

    The agglomeration phenomenon of amorphous particulate material is a major problem in the food industry. Currently, the glass transition temperature (Tg) is used as a fundamental parameter to describe and control agglomeration. Models are available that describe the kinetics of the agglomeration proc

  3. Labor market pooling and occupational agglomeration

    OpenAIRE

    Gabe, Todd M.; Jaison R. Abel

    2009-01-01

    This paper examines the micro-foundations of occupational agglomeration in U.S. metropolitan areas, with an emphasis on labor market pooling. Controlling for a wide range of occupational attributes, including proxies for the use of specialized machinery and for the importance of knowledge spillovers, we find that jobs characterized by a unique knowledge base exhibit higher levels of geographic concentration than do occupations with generic knowledge requirements. Further, by analyzing co-aggl...

  4. 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.

  5. Ukrainian experience of oil agglomeration of coals

    Energy Technology Data Exchange (ETDEWEB)

    Biletskyi, V.S. [Donetsk State Technical University, Donetsk (Ukraine). Dept. of Coal Preparation

    1997-12-31

    During the years 1980-1996 a series of investigations related to the applied and theoretical aspects of the coal oil agglomeration processing were carried out in the Ukraine at the Donetsk State Technical University and Coal Chemistry National Academy of Sciences (NAN) of Ukraine, institutes UralVTI, VNIIPIHidrotruboprovod, LenNIlkhimmash, Kharkiv polytechnical Institute, Institute of Biocolloide Chemistry NAN of Ukraine and also at coal preparation plants and thermoelectric power stations in the Donbas. Theoretical bases of the process of selective oil agglomeration are developed on the basis of modern physical chemistry, physical-chemical hydrodynamics, adhesion theory, and solid fuel chemistry. The necessary sufficient conditions for aggregate forming coal and oil components in water have been formulated. The central problem of `coal-reagent` interaction during coal aggregation has been solved, and a mathematical description of processes for forming coal-oil aggregates including kinetics has been made. Analysis of factors which influence the process and its mathematical models have been realized. Rational conditions of pelletising of energetic and coking coal, coal raw material and products of coal preparation plants, electric power stations, and hydrotransport systems have been determined. Results of the complex study of technological properties of coal aggregates as objects of dewatering, hydrotransportation, consumption, coking, pyrolysis and carriers at gold adhesive preparation are presented. The theoretical principles and experimental data served as a basis for creating about 40 new methods and devices for the process of coal selective oil agglomeration. 14 refs., 7 figs., 1 tab.

  6. 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.

  7. Factors influencing particle agglomeration during solid-state sintering

    Institute of Scientific and Technical Information of China (English)

    Chao Wang; Shao-Hua Chen

    2012-01-01

    Discrete element method (DEM) is used to study the factors affecting agglomeration in three-dimensional copper particle systems during solid-state sintering.A new parameter is proposed to characterize agglomeration.The effects of a series of factors are studied,including particle size,size distribution,inter-particle tangential viscosity,temperature,initial density and initial distribution of particles on agglomeration.We find that the systems with smaller particles,broader particle size distribution,smaller viscosity,higher sintering temperature and smaller initial density have stronger particle agglomeration and different distributions of particles induce different agglomerations.This study should be very useful for understanding the phenomenon of agglomeration and the micro-structural evolution during sintering and guiding sintering routes to avoid detrimental agglomeration.

  8. THE SYNERGISTIC EFFECT OF MIXED XEROGRAPHIC TONER AGGLOMERATION

    Directory of Open Access Journals (Sweden)

    Cuixia Wang,

    2012-06-01

    Full Text Available Agglomeration phenomena of two mixed xerographic toners were investigated using 1-octadecanol as the agglomeration agent and a cationic surfactant as the co-agglomeration agent. One toner carrying no surface charge agglomerated well under most conditions, while the other toner carrying a negative surface charge performed worse. It was found that when mixing these two toners together during pulping and when using 1-octadecanol as the agglomeration agent alone, there was an additive effect on agglomeration. On the other hand, addition of a small amount of cationic surfactant dramatically enhanced the mixed toner agglomeration efficiency and generated an obvious synergistic effect. The particle number after agglomeration was significantly reduced, and the particle size was greatly increased compared to the single toner agglomeration. The optimal amount of the cationic surfactant was close to the optimal cationic surfactant demand of the negatively charged toner. Based on these findings it can be recommended that the cationic surfactant should be added during agglomeration of the mixed office waste paper, and its optimal dosage needs to be chosen to reach the best performance.

  9. 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.

  10. Multifrequency scanning probe microscopy study of nanodiamond agglomerates

    Science.gov (United States)

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

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

  11. Agglomeration in a fluidized bed using multiple jet streams

    Energy Technology Data Exchange (ETDEWEB)

    Rehmat, A.; Abbasian, J. (Institute of Gas Technology, Chicago, IL (United States)); Kothari, M.; Hariri, H.; Arastoopour, H. (Illinois Inst. of Tech., Chicago, IL (United States))

    1992-01-01

    Tests were conducted to determine the overall temperature distribution, temperature in the vicinity of the jets, and the rate of agglomeration in a fluidized bed containing multiple jet streams. Agglomeration of ash during coal gasification increases carbon utilization efficiency considerably. The agglomeration requires a fluidized-bed reactor with a specially designed distributor equipped with a jet to yield a hot zone confined within the bed. The rate of agglomeration depends upon the size and the intensity of the zone. This rate, and hence the unit capacity, could be increased by adding multiple jets to the distributor. The purpose of this study was to verify this phenomenon. The temperature distribution inside the agglomerating fluidized-bed reactor with a single jet was studied by Hariri et al. Various parameters were involved in agglomeration phenomena -- bed material, fluidization velocity, bed temperature, jet velocity, jet temperature, bed geometry, and distributor geometry. Controlled agglomerates were produced in the fluidized bed when a sloped gas distributor consisting of a central jet and a porous plate was used. Gas at temperatures above the melting temperature of a bed material was introduced into the jet and gas at temperatures below the softening temperature was introduced into the distributor. The rate of agglomerate formation was significantly influenced by an increase in either jet air or auxiliary (grid) air temperature. The extent of agglomeration also depended strongly upon the volume of the hot zone confined within the isotherms with temperatures higher than the melting point of the bed material.

  12. Agglomeration in a fluidized bed using multiple jet streams

    Energy Technology Data Exchange (ETDEWEB)

    Rehmat, A.; Abbasian, J. [Institute of Gas Technology, Chicago, IL (United States); Kothari, M.; Hariri, H.; Arastoopour, H. [Illinois Inst. of Tech., Chicago, IL (United States)

    1992-12-31

    Tests were conducted to determine the overall temperature distribution, temperature in the vicinity of the jets, and the rate of agglomeration in a fluidized bed containing multiple jet streams. Agglomeration of ash during coal gasification increases carbon utilization efficiency considerably. The agglomeration requires a fluidized-bed reactor with a specially designed distributor equipped with a jet to yield a hot zone confined within the bed. The rate of agglomeration depends upon the size and the intensity of the zone. This rate, and hence the unit capacity, could be increased by adding multiple jets to the distributor. The purpose of this study was to verify this phenomenon. The temperature distribution inside the agglomerating fluidized-bed reactor with a single jet was studied by Hariri et al. Various parameters were involved in agglomeration phenomena -- bed material, fluidization velocity, bed temperature, jet velocity, jet temperature, bed geometry, and distributor geometry. Controlled agglomerates were produced in the fluidized bed when a sloped gas distributor consisting of a central jet and a porous plate was used. Gas at temperatures above the melting temperature of a bed material was introduced into the jet and gas at temperatures below the softening temperature was introduced into the distributor. The rate of agglomerate formation was significantly influenced by an increase in either jet air or auxiliary (grid) air temperature. The extent of agglomeration also depended strongly upon the volume of the hot zone confined within the isotherms with temperatures higher than the melting point of the bed material.

  13. Negative polarization of agglomerate particles with various densities

    Directory of Open Access Journals (Sweden)

    Y. Shkuratov

    2011-09-01

    Full Text Available We study the negative polarization produced by agglomerate particles of various density. We found that all types of agglomerates studied reveal similar dependence of negative polarization minimum Pmin and its location αmin on particle size and refractive index.

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

    Science.gov (United States)

    2012-05-08

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

  15. Numerical study of agglomerate abrasion in a tumbling mixer

    NARCIS (Netherlands)

    Thanh Nguyen, [No Value; Willemsz, Tofan; Frijlink, Henderik; Maarschalk, Kees van der Voort

    2014-01-01

    A numerical simulation using the Discrete Element Method (DEM) was performed to investigate the phenomena concerning the abrasion and breakage of agglomerates in a diffusion powder mixer. Agglomerates were created by defining a single structure of particles with bonds of different strengths using th

  16. 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 transp......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...

  17. 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

  18. 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

  19. Agglomerates containing pantoprazole microparticles: modulating the drug release.

    Science.gov (United States)

    Raffin, Renata P; Colombo, Paolo; Sonvico, Fabio; Rossi, Alessandra; Jornada, Denise S; Pohlmann, Adriana R; Guterres, Silvia S

    2009-01-01

    Pantoprazole-loaded microparticles were prepared using a blend of Eudragit S100 and Methocel F4M. The accelerated stability was carried out during 6 months at 40 degrees C and 75% relative humidity. In order to improve technological characteristics of the pantoprazole-loaded microparticles, soft agglomerates were prepared viewing an oral delayed release and gastro-resistant solid dosage form. The agglomeration was performed by mixing the pantoprazole microparticles with spray-dried mannitol/lecithin powders. The effects of factors such as the amount of lecithin in the spray-dried mannitol/lecithin powders and the ratio between pantoprazole microparticles and spray-dried mannitol/lecithin powders were evaluated. The pantoprazole-loaded microparticles present no significant degradation in 6 months. The agglomerates presented spherical shape, with smooth surface and very small quantity of non-agglomerated particles. The agglomerates presented different yields (35.5-79.0%), drug loading (58-101%), and mechanical properties (tensile strength varied from 44 to 69 mN mm(-2)), when the spray-dried mannitol/lecithin powders with different lecithin amounts were used. The biopharmaceutical characteristics of pantoprazole microparticles, i.e., their delayed-release properties, were not affected by the agglomeration process. The gastro-resistance of the agglomerates was affected by the amount of spray-dried mannitol/lecithin powders. The ratio of lecithin in the spray-dried mannitol/lecithin powders was the key factor in the agglomerate formation and in the drug release profiles. The agglomerates presenting better mechanical and biopharmaceutical characteristics were prepared with 1:2 (w/w) ratio of pantoprazole-loaded microparticles and mannitol/lecithin (80:20) powder.

  20. 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.

  1. Physical properties of soils in Rostov agglomeration

    Science.gov (United States)

    Gorbov, S. N.; Bezuglova, O. S.; Abrosimov, K. N.; Skvortsova, E. B.; Tagiverdiev, S. S.; Morozov, I. V.

    2016-08-01

    Physical properties of natural and anthropogenically transformed soils of Rostov agglomeration were examined. The data obtained by conventional methods and new approaches to the study of soil physical properties (in particular, tomographic study of soil monoliths) were used for comparing the soils of different functional zones of the urban area. For urban territories in the steppe zone, a comparison of humus-accumulative horizons (A, Asod, Ap, and buried [A] horizons) made it possible to trace tendencies of changes in surface soils under different anthropogenic impacts and in the buried and sealed soils. The microtomographic study demonstrated differences in the bulk density and aggregation of urban soils from different functional zones. The A horizon in the forest-park zone is characterized by good aggregation and high porosity, whereas buried humus-accumulative horizons of anthropogenically transformed soils are characterized by poor aggregation and low porosity. The traditional parameters of soil structure and texture also proved to be informative for the identification of urban pedogenesis.

  2. 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.

  3. 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)

  4. Acoustic agglomeration of power plant fly ash. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Reethof, G.; McDaniel, O.H.

    1982-01-01

    The work has shown that acoustic agglomeration at practical acoustic intensities and frequencies is technically and most likely economically viable. The following studies were performed with the listed results: The physics of acoustic agglomeration is complex particularly at the needed high acoustic intensities in the range of 150 to 160 dB and frequencies in the 2500 Hz range. The analytical model which we developed, although not including nonlinear acoustic efforts, agreed with the trends observed. We concentrated our efforts on clarifying the impact of high acoustic intensities on the generation of turbulence. Results from a special set of tests show that although some acoustically generated turbulence of sorts exists in the 150 to 170 dB range with acoustic streaming present, such turbulence will not be a significant factor in acoustic agglomeration compared to the dominant effect of the acoustic velocities at the fundamental frequency and its harmonics. Studies of the robustness of the agglomerated particles using the Anderson Mark III impactor as the source of the shear stresses on the particles show that the agglomerates should be able to withstand the rigors of flow through commercial cyclones without significant break-up. We designed and developed a 700/sup 0/F tubular agglomerator of 8'' internal diameter. The electrically heated system functioned well and provided very encouraging agglomeration results at acoustic levels in the 150 to 160 dB and 2000 to 3000 Hz ranges. We confirmed earlier results that an optimum frequency exists at about 2500 Hz and that larger dust loadings will give better results. Studies of the absorption of acoustic energy by various common gases as a function of temperature and humidity showed the need to pursue such an investigation for flue gas constituents in order to provide necessary data for the design of agglomerators. 65 references, 56 figures, 4 tables.

  5. Defect agglomeration in ferroelectric ceramics under cyclic electric field

    Institute of Scientific and Technical Information of China (English)

    GENG LiMing; YANG Wei

    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.

  6. 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.

  7. Agglomeration economies and global activities: impact on firm survival

    OpenAIRE

    FERRAGINA, Anna Maria; Mazzotta, Fernanda

    2014-01-01

    The focus of our contribution is to shed light on the importance of firm agglomerations and FDI as drivers of firm survival in Italy. We focus upon different types of agglomeration economies related to the geographical context checking how these economies impact differently on heterogeneous firms survival and whether effects are robust to different estimators (Probit, Cox hazard models, Probit Heckman) and to different assumptions about inter-and intra-regional spillovers. The novelty our pap...

  8. Agglomeration Control during Ultrasonic Crystallization of an Active Pharmaceutical Ingredient

    Directory of Open Access Journals (Sweden)

    Bjorn Gielen

    2017-02-01

    Full Text Available Application of ultrasound during crystallization can efficiently inhibit agglomeration. However, the mechanism is unclear and sonication is usually enabled throughout the entire process, which increases the energy demand. Additionally, improper operation results in significant crystal damage. Therefore, the present work addresses these issues by identifying the stage in which sonication impacts agglomeration without eroding the crystals. This study was performed using a commercially available API that showed a high tendency to agglomerate during seeded crystallization. The crystallization progress was monitored using process analytical tools (PAT, including focus beam reflectance measurements (FBRM to track to crystal size and number and Fourier transform infrared spectroscopy (FTIR to quantify the supersaturation level. These tools provided insight in the mechanism by which ultrasound inhibits agglomeration. A combination of improved micromixing, fast crystal formation which accelerates depletion of the supersaturation and a higher collision frequency prevent crystal cementation to occur. The use of ultrasound as a post-treatment can break some of the agglomerates, but resulted in fractured crystals. Alternatively, sonication during the initial seeding stage could assist in generating nuclei and prevent agglomeration, provided that ultrasound was enabled until complete desupersaturation at the seeding temperature. FTIR and FBRM can be used to determine this end point.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. AMG by element agglomeration and constrained energy minimization interpolation

    Energy Technology Data Exchange (ETDEWEB)

    Kolev, T V; Vassilevski, P S

    2006-02-17

    This paper studies AMG (algebraic multigrid) methods that utilize energy minimization construction of the interpolation matrices locally, in the setting of element agglomeration AMG. The coarsening in element agglomeration AMG is done by agglomerating fine-grid elements, with coarse element matrices defined by a local Galerkin procedure applied to the matrix assembled from the individual fine-grid element matrices. This local Galerkin procedure involves only the coarse basis restricted to the agglomerated element. To construct the coarse basis, one exploits previously proposed constraint energy minimization procedures now applied to the local matrix. The constraints are that a given set of vectors should be interpolated exactly, not only globally, but also locally on every agglomerated element. The paper provides algorithmic details, as well as a convergence result based on a ''local-to-global'' energy bound of the resulting multiple-vector fitting AMG interpolation mappings. A particular implementation of the method is illustrated with a set of numerical experiments.

  14. 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.

  15. Flocculation, hydrophobic agglomeration and filtration of ultrafine coal

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Z. [University of British Columbia, Vancouver, BC (Canada). Department of Mineral and Mineral Process Engineering

    1999-07-01

    Selective flocculation tests were run on three types of coal and three additives in tests on a new hydrophobic agglomeration process using hydrophobic latices. The coals differed widely in surface wettability. The additives were hydrophobic latexes, a semi-hydrophobic flocculant, and a typical hydrophilic polyelectrolyte. The results show that coal wettability is very important in selective flocculation. UBC-1 hydrophobic latex flocculated hydrophobic coal particles only, while the polyelectrolyte flocculated all the coal samples and minerals that were tested. Tests of oil agglomeration using kerosene emulsified with surfactants of various ionic properties show that even oxidized coals can be agglomerated, if cationic surfactants are used to emulsify the oil. The hydrophobic latex and emulsified oils also significantly increase filtration rate and reduce filter cake moisture content.

  16. 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.

  17. Ice slurry cooling research: Storage tank ice agglomeration and extraction

    Energy Technology Data Exchange (ETDEWEB)

    Kasza, K. [Argonne National Lab., IL (United States); Hayashi, Kanetoshi [NKK Corp., Kawasaki (Japan)

    1999-08-01

    A new facility has been built to conduct research and development on important issues related to implementing ice slurry cooling technology. Ongoing studies are generating important information on the factors that influence ice particle agglomeration in ice slurry storage tanks. The studies are also addressing the development of methods to minimize and monitor agglomeration and improve the efficiency and controllability of tank extraction of slurry for distribution to cooling loads. These engineering issues impede the utilization of the ice slurry cooling concept that has been under development by various groups.

  18. 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.

  19. MEASUREMENT OF AGGLOMERATION ECONOMIES AT COUNTY LEVEL IN JIANGSU PROVINCE

    Institute of Scientific and Technical Information of China (English)

    GE Ying; PU Ying-xia; YAO Shi-mou

    2005-01-01

    Agglomeration economies are the important factors for the regional development. However, the common indicators to measure them, such as Gini Coefficients neglect the spatial ingredient of data, leading to a-spatial estimates. In order to assess spatial neighbor effects of agglomeration economies, this study makes the new attempts by applying a series of techniques of spatial autocorrelation analysis, specifically, measuring the economies of urbanization and localization at the county level in the secondary and tertiary industries of Jiangsu Province in 1999 and 2002. The conclusions in this study reveal that on the whole, the localization effects on the economies of the secondary industry might be stronger than urbanization effects for that period, and highly agglomerative economies were limited within the southern Jiangsu and parts of middle along the Changjiang (Yangtze) River. Moreover, the tertiary industry has been strong urbanization rather than localization economies in the whole Jiangsu. Unlike the secondary industry, the tertiary industry held the high levels of agglomeration economies can be also found in the poor northern Jiangsu, and then the spatial clusters of trade and services might be basically seen in each of urban districts in 13 cities. All in all, spatial autocorrelation analysis is a better method to test agglomeration economies.

  20. Frequency comparative study of coal-fired fly ash acoustic agglomeration

    Institute of Scientific and Technical Information of China (English)

    Jianzhong Liu; Jie Wang; Guangxue Zhang; Junhu Zhou; Kefa Cen

    2011-01-01

    Particulate pollution is main kind of atmospheric pollution.The fine particles are seriously harmful to human health and environment.Acoustic agglomeration is considered as a promising pretreatment technology for fine particle agglomeration.The mechanisms of acoustic agglomeration are very complex and the agglomeration efficiency is affected by many factors.The most important and controversial factor is frequency.Comparative studies between high-frequency and low-frequency sound source to agglomerate coalfired fly ash were carried out to investigate the influence of frequency on agglomeration efficiency.Acoustic agglomeration theoretical analysis,experimental particle size distributions (PSDs) and orthogonal design were examined.The results showed that the 20 kHz high-frequency sound source was not suitable to agglomerate coal-fired fly ash.Only within the size ranging from 0.2 to 0.25 μm the particles agglomerated to adhere together,and the agglomerated particles were smaller than 2.5 μm.The application of low-frequency (1000-1800 Hz) sound source was proved as an advisable pretreatment with the highest agglomeration efficiency of 75.3%,and all the number concentrations within the measuring range decreased.Orthogonal design L16 (4)3 was introduced to determine the optimum frequency and optimize acoustic agglomeration condition.According to the results of orthogonal analysis,frequency was the dominant factor of coal-fired fly ash acoustic agglomeration and the optimum frequency was 1400 Hz.

  1. Phosphate-enhanced cytotoxicity of zinc oxide nanoparticles and agglomerates.

    Science.gov (United States)

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

    2014-02-10

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

  2. Comments on an Analytical Thermal Agglomeration for Problems with Surface Growth

    Energy Technology Data Exchange (ETDEWEB)

    Hodge, N. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-03-22

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

  3. Literature review and binder and coal selection for research studies on coal agglomeration

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, S.G.; Kuby, O.A.; Girimont, J.A.; peterson, C.A.; Saller, E.

    1982-02-26

    This report discusses the results of a literature survey on coal agglomeration and the approaches that were employed in selecting binders and coals to be studied in a process development program currently being performed for the Department of Energy. The survey is the first step toward the development of a useful process for the agglomeration of coal fines for use in a fixed-bed gasifier. Literature was found and reviewed on the effects of coal composition and physical properties, on agglomeration techniques and operating variables, on binders or additives to promote agglomeration, on pretreatment techniques on agglomerate feedstocks and post-treatment techniques on formed agglomerates, and on test results obtained by researchers in the past using various additives, treatments and agglomeration techniques. Much of this information did not deal directly with agglomerates for fixed-bed gasifiers, but the reported observations and results could be extrapolated to give useful guidelines for research plans. Conclusions and plans for further work are presented.

  4. 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.

  5. Water migration mechanisms in amorphous powder material and related agglomeration propensity

    NARCIS (Netherlands)

    Renzetti, S.; Voogt, J.A.; Oliver, L.; Meinders, M.B.J.

    2012-01-01

    The agglomeration phenomenon of amorphous particulate material is a major problem in the food industry. Currently, the glass transition temperature (Tg) is used as a fundamental parameter to describe and control agglomeration. Models are available that describe the kinetics of the agglomeration proc

  6. 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.

  7. Functionally graded porous scaffolds made of Ti-based agglomerates.

    Science.gov (United States)

    Nazari, Keivan A; Hilditch, Tim; Dargusch, Matthew S; Nouri, Alireza

    2016-10-01

    Mono- and double-layer porous scaffolds were successfully fabricated using ball-milled agglomerates of Ti and Ti-10Nb-3Mo alloy. For selectively controlling the level of porosity and pore size, the agglomerates were sieved into two different size fractions of 100-300μm and 300-500μm. Compressive mechanical properties were measured on a series of cylindrical sintered compacts with different ratios of solid core diameter to porous layer width. The graded porous scaffolds exhibited stress-strain curves typical for metallic foams with a defined plateau region after yielding. The compressive strengths and elastic moduli ranged from 300 to 700MPa and 14 to 55GPa, respectively, depending on the core diameter and the material used. The obtained properties make these materials suitable for load-bearing implant applications.

  8. 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...

  9. 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

  10. Public Action and Innovationsupport Institutions in New Technological Agglomerations

    DEFF Research Database (Denmark)

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

    2002-01-01

    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...... on the major efforts of different public actors in the territory since the 1980s, mainly through the establishment and enhancement of innovation-support institutions, and analyses succinctly their effects through selected successful and failed cases. Two normative statements are suggested from the analysis...... into an open explicit option for the economic performance of the territory. The conclusions include a final plea for further research about the industrial dynamics and knowledge flows in the Vallès Occidental County, an important growth pole of Catalonia....

  11. 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.

  12. 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.

  13. Field observations of artificial sand and oil agglomerates

    Science.gov (United States)

    Dalyander, Patricia (Soupy); Long, Joseph W.; Plant, Nathaniel G.; McLaughlin, Molly R.; Mickey, Rangley C.

    2015-01-01

    Oil that comes into the surf zone following spills, such as occurred during the 2010 Deepwater Horizon (DWH) blowout, can mix with local sediment to form heavier-than-water sand and oil agglomerates (SOAs), at times in the form of mats a few centimeters thick and tens of meters long. Smaller agglomerates that form in situ or pieces that break off of larger mats, sometimes referred to as surface residual balls (SRBs), range in size from sand-sized grains to patty-shaped pieces several centimeters (cm) in diameter. These mobile SOAs can cause beach oiling for extended periods following the spill, on the scale of years as in the case of DWH. Limited research, including a prior effort by the U.S. Geological Survey (USGS) investigating SOA mobility, alongshore transport, and seafloor interaction using numerical model output, focused on the physical dynamics of SOAs. To address this data gap, we constructed artificial sand and oil agglomerates (aSOAs) with sand and paraffin wax to mimic the size and density of genuine SOAs. These aSOAs were deployed in the nearshore off the coast of St. Petersburg, Florida, during a field experiment to investigate their movement and seafloor interaction. This report presents the methodology for constructing aSOAs and describes the field experiment. Data acquired during the field campaign, including videos and images of aSOA movement in the nearshore (1.5-meter and 0.5-meter water depth) and in the swash zone, are also presented in this report.

  14. A phenomenological model for improving understanding of the ammonium nitrate agglomeration process

    Directory of Open Access Journals (Sweden)

    Videla Leiva Alvaro

    2016-01-01

    Full Text Available Ammonium nitrate is intensively used as explosive in the mining industry as the main component of ANFO. The ammonium nitrate is known to be a strong hygroscopic crystal matter which generates problems due to the creation of water bridges between crystals leading later to nucleation and crystallization forming an agglomerated solid cake. The agglomeration process damages the ammonium nitrate performance and is undesirable. Usually either organic or inorganic coatings are used to control agglomeration. In the present work a characterization method of humidity adsorption of the ammonium nitrate crystal was performed under laboratory conditions. Several samples were exposed into a defined humidity in a controlled chamber during 5 hours after which the samples were tested to measure agglomeration as the resistance force to compression. A clear relation was found between coating protection level, humidity and agglomeration. Agglomeration can be then predicted by a phenomenological model based of combination of the mono-layer BET adsorption and CNT nucleation models.

  15. 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.

  16. Agglomeration of Luminescent Porous Silicon Nanoparticles in Colloidal Solutions

    Science.gov (United States)

    Herynková, Kateřina; Šlechta, Miroslav; Šimáková, Petra; Fučíková, Anna; Cibulka, Ondřej

    2016-08-01

    We have prepared colloidal solutions of clusters composed from porous silicon nanoparticles in methanol, water and phosphate-buffered saline (PBS). Even if the size of the nanoclusters is between 60 and 500 nm, due to their highly porous "cauliflower"-like structure, the porous silicon nanoparticles are composed of interconnected nanocrystals having around 2.5 nm in size and showing strong visible luminescence in the orange-red spectral region (centred at 600-700 nm). Hydrophilic behaviour and good solubility of the nanoclusters in water and water-based solutions were obtained by adding hydrogen peroxide into the etching solution during preparation and 16 min long after-bath in hydrogen peroxide. By simple filtration of the solutions with syringe filters, we have extracted smaller nanoclusters with sizes of approx. 60-70 nm; however, these nanoclusters in water and PBS solution (pH neutral) are prone to agglomeration, as was confirmed by zeta potential measurements. When the samples were left at ambient conditions for several weeks, the typical nanocluster size increased to approx. 330-400 nm and then remained stable. However, both freshly filtered and aged samples (with agglomerated porous silicon nanoparticles) of porous silicon in water and PBS solutions can be further used for biological studies or as luminescent markers in living cells.

  17. Agglomeration of Luminescent Porous Silicon Nanoparticles in Colloidal Solutions.

    Science.gov (United States)

    Herynková, Kateřina; Šlechta, Miroslav; Šimáková, Petra; Fučíková, Anna; Cibulka, Ondřej

    2016-12-01

    We have prepared colloidal solutions of clusters composed from porous silicon nanoparticles in methanol, water and phosphate-buffered saline (PBS). Even if the size of the nanoclusters is between 60 and 500 nm, due to their highly porous "cauliflower"-like structure, the porous silicon nanoparticles are composed of interconnected nanocrystals having around 2.5 nm in size and showing strong visible luminescence in the orange-red spectral region (centred at 600-700 nm). Hydrophilic behaviour and good solubility of the nanoclusters in water and water-based solutions were obtained by adding hydrogen peroxide into the etching solution during preparation and 16 min long after-bath in hydrogen peroxide. By simple filtration of the solutions with syringe filters, we have extracted smaller nanoclusters with sizes of approx. 60-70 nm; however, these nanoclusters in water and PBS solution (pH neutral) are prone to agglomeration, as was confirmed by zeta potential measurements. When the samples were left at ambient conditions for several weeks, the typical nanocluster size increased to approx. 330-400 nm and then remained stable. However, both freshly filtered and aged samples (with agglomerated porous silicon nanoparticles) of porous silicon in water and PBS solutions can be further used for biological studies or as luminescent markers in living cells.

  18. 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.

  19. Flue Dust Agglomeration in the Secondary Lead Industry

    Science.gov (United States)

    Schwitzgebel, Klaus

    1981-01-01

    A secondary lead smelter produces several tons of bag-house dust a day. Appropriate handling of this dust is mandatory to meet the proposed OSHA and EPA workroom and ambient standards. Dust agglomeration proved a successful approach. Dusts with a high concentration of PbCl2, or compounds containing PbCl2 can be agglomerated at much lower temperatures than samples with low PbCl2 concentrations. The chlorine sources are polyvinyl chloride (PVC) battery plate separators. Since PVC is used in Europe to a much greater extent than in the U.S., the composition of feedstock must be considered in equipment selection at U.S. secondary smelters. The vapor pressure characteristics of PbCl2 favor its evaporation at blast furnace temperatures. Condensation occurs in the gas cooling system. Recycling of baghouse dust leads to a buildup of PbCl2 in the smelter. Its removal from the system is eventually necessary through leaching, if charges with a high PVC content are processed.

  20. On minimal energy dipole moment distributions in regular polygonal agglomerates

    Science.gov (United States)

    Rosa, Adriano Possebon; Cunha, Francisco Ricardo; Ceniceros, Hector Daniel

    2017-01-01

    Static, regular polygonal and close-packed clusters of spherical magnetic particles and their energy-minimizing magnetic moments are investigated in a two-dimensional setting. This study focuses on a simple particle system which is solely described by the dipole-dipole interaction energy, both without and in the presence of an in-plane magnetic field. For a regular polygonal structure of n sides with n ≥ 3 , and in the absence of an external field, it is proved rigorously that the magnetic moments given by the roots of unity, i.e. tangential to the polygon, are a minimizer of the dipole-dipole interaction energy. Also, for zero external field, new multiple local minima are discovered for the regular polygonal agglomerates. The number of found local extrema is proportional to [ n / 2 ] and these critical points are characterized by the presence of a pair of magnetic moments with a large deviation from the tangential configuration and whose particles are at least three diameters apart. The changes induced by an in-plane external magnetic field on the minimal energy, tangential configurations are investigated numerically. The two critical fields, which correspond to a crossover with the linear chain minimal energy and with the break-up of the agglomerate, respectively are examined in detail. In particular, the numerical results are compared directly with the asymptotic formulas of Danilov et al. (2012) [23] and a remarkable agreement is found even for moderate to large fields. Finally, three examples of close-packed structures are investigated: a triangle, a centered hexagon, and a 19-particle close packed cluster. The numerical study reveals novel, illuminating characteristics of these compact clusters often seen in ferrofluids. The centered hexagon is energetically favorable to the regular hexagon and the minimal energy for the larger 19-particle cluster is even lower than that of the close packed hexagon. In addition, this larger close packed agglomerate has two

  1. Constructing Political Region Agglomerations for Effective Science Communcation

    Science.gov (United States)

    Rising, J. A.

    2015-12-01

    Often political regions form a better scale for modeling than regulargrids, since they are used for collecting socioeconomic data and aremore relevant to stakeholders and policy-makers. However, differentpolitical regions can enclose very different areas, populations,ranges of climatic variability, and for many countries there are anundesireable number of regions available at any administrative level.We provide a solution to this problem, by providing a general systemfor agglomerating regions to a larger scale, to approximately optimizearbitrary objectives. These regions provide an intermediate scale formodeling and greater comparability than unagglomerated regions. Wefirst apply the approach to the US, producing region agglomerationsthat normalize region size, population, income, and climaticvariability. We then apply the technique globally, generating acononical collection of regions for studying the impacts of climatechange.

  2. Agglomeration and Deposition Behaviour of Solid Recovered Fuel

    DEFF Research Database (Denmark)

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

    2016-01-01

    Waste-derived fuels, such as solid recovered fuel (SRF), are increasingly being used in, e.g., the cement industry as a means to reduce cost. The inhomogeneous nature of SRF makes it difficult to combust, and many problems may arise within, e.g., combustion control, feeding of fuel, deposit...... 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...... could be monitored. PE and PP pose no significant risk of forming deposits in a combustion environment (T > 800 °C) as a result of a rapid devolatilization, while PET may cause deposits as a result of a sticky char residue. The deposition tendency of the investigated SRF is low, and it may be managed...

  3. 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.

  4. Agglomeration and Deposition Behaviour of Solid Recovered Fuel

    DEFF Research Database (Denmark)

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

    2015-01-01

    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...... 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...... of PET [11,12]. The main objective of this study was to characterize the combustion of SRF and especially the deposition propensity of SRF and the main constituents of SRF. This relates both to the low temperature deposits formed during plastic pyrolysis and the high temperature deposits formed by ash...

  5. 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.

  6. Agglomeration in fluidized beds at high temperatures: Mechanisms, detection and prevention

    Energy Technology Data Exchange (ETDEWEB)

    Malte Bartels; Weigang Lin; John Nijenhuis; Freek Kapteijn; J. Ruud van Ommen [Delft University of Technology - DelftChemTech, Delft (Netherlands)

    2008-10-15

    Fluidized-bed conversion of solid fuels is a well-established and widely used technology. Yet, operational problems are encountered in industrial practice. One of the most important problems is the occurrence of agglomeration at high temperature, meaning that bed particles adhere to each other to form larger entities (agglomerates). This process is often not recognized until sudden defluidization and often leads to a costly shutdown of the whole installation. In particular, the thermal conversion of certain biomass fuels, which is becoming increasingly popular, increases the risk of agglomeration. This paper critically reviews the current research status of this topic in terms of agglomeration mechanisms, detection and counteraction strategies. To understand the complex phenomenon of agglomeration in fluidized beds at high temperatures different areas are distinguished viz. hydrodynamics, chemical reaction mechanisms, particle interaction mechanisms and molecular cramming. Special emphasis is given to the detection of agglomeration. The range of detection methods is comprised of fuel ash analysis methods to predict potential agglomeration as well as analysis methods based on (on-line) process measurements, such as pressure and temperature. Finally, different methods to counteract agglomeration phenomena are presented; they comprise operational measures, utilization of additives, alternative bed materials and improved reactor design. 176 refs., 22 figs., 1 tab.

  7. A model to estimate the size of nanoparticle agglomerates in gas−solid fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Martín, Lilian de, E-mail: L.DeMartinMonton@tudelft.nl; Ommen, J. Ruud van [Delft University of Technology, Department of Chemical Engineering (Netherlands)

    2013-11-15

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

  8. Productive Places : The influence of technological change and relatedness on agglomeration externalities

    NARCIS (Netherlands)

    Neffke, F.M.H.

    2009-01-01

    This thesis addresses the topic of agglomeration externalities. Agglomeration externalities can roughly be defined as advantages and disadvantages local firms experience when locating close to other firms. An old debate exists over the question whether firms benefit more from being close to firms in

  9. A MODEL FOR FINE PARTICLE AGGLOMERATION IN CIRCULATING FLUIDIZED BED ABSORBERS

    Science.gov (United States)

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

  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. 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.

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

    Science.gov (United States)

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

    2013-03-01

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

  14. 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.

  15. 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.

  16. Gravitational agglomeration of post-HCDA LMFBR nonspherical aerosols

    Science.gov (United States)

    Tuttle, R. F.

    1980-12-01

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

  17. Monitoring of odor nuisance in the tri-city agglomeration

    Science.gov (United States)

    Gebicki, Jacek; Dymerski, Tomasz; Namieśnik, Jacek

    2016-11-01

    The paper describes a principle of operation of odor nuisance monitoring network, which is being designed in the tri-city agglomeration. Moreover, it presents the preliminary results of an investigation on ambient air quality with respect to odour nuisance in a vicinity of the municipal landfill. The investigation was performed during spring-winter season using a prototype of electronic nose and the Nasal Ranger field olfactometers. The prototype was equipped with a set of six semiconductor sensors by FIGARO Co. and one PID-type sensor. The field olfactometers were used to determine mean concentration of odorants, which amounted from 2.2 to 30.2 ou/m3 depending on the place of measurement. In case of the investigation with the electronic nose prototype a classification of the ambient air samples with respect to the place of sampling was performed utilizing kNN algorithm supported with a cross-validation method. Correct classification of the ambient air samples was at the level of 66.7%. Performed investigation revealed that discrimination of the ambient air samples differing in concentration of odorants and place of origin was possible.

  18. 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.

  19. 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.

  20. 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.

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

    Science.gov (United States)

    Huber, Dale L.

    2011-07-05

    A method for controlling the size of chemically synthesized magnetic nanoparticles that employs magnetic interaction between particles to control particle size and does not rely on conventional kinetic control of the reaction to control particle size. The particles are caused to reversibly agglomerate and precipitate from solution; the size at which this occurs can be well controlled to provide a very narrow particle size distribution. The size of particles is controllable by the size of the surfactant employed in the process; controlling the size of the surfactant allows magnetic control of the agglomeration and precipitation processes. Agglomeration is used to effectively stop particle growth to provide a very narrow range of particle sizes.

  2. The Physics of Protoplanetesimal Dust Agglomerates. V. Multiple Impacts of Dusty Agglomerates at Velocities Above the Fragmentation Threshold

    Science.gov (United States)

    Kothe, Stefan; Güttler, Carsten; Blum, Jürgen

    2010-12-01

    In recent years, a number of new experiments have advanced our knowledge on the early growth phases of protoplanetary dust aggregates. Some of these experiments have shown that collisions between porous and compacted agglomerates at velocities above the fragmentation threshold velocity can lead to growth of the compact body, when the porous collision partner fragments upon impact and transfers mass to the compact agglomerate. To obtain a deeper understanding of this potentially important growth process, we performed laboratory and drop tower experiments to study multiple impacts of small, highly porous dust-aggregate projectiles onto sintered dust targets. The projectile and target consisted of 1.5 μm monodisperse, spherical SiO2 monomers with volume filling factors of 0.15 ± 0.01 and 0.45 ± 0.05, respectively. The fragile projectiles were accelerated by a solenoid magnet and combined with a projectile magazine with which 25 impacts onto the same spot on the target could be performed in vacuum. We measured the mass-accretion efficiency and the volume filling factor for different impact velocities between 1.5 and 6.0 m s^{-1}. The experiments at the lowest impact speeds were performed in the Bremen drop tower under microgravity conditions to allow partial mass transfer also for the lowest adhesion case. Within this velocity range, we found a linear increase of the accretion efficiency with increasing velocity. In the laboratory experiments, the accretion efficiency increases from 0.12 to 0.21 in units of the projectile mass. The recorded images of the impacts showed that the mass transfer from the projectile to the target leads to the growth of a conical structure on the target after less than 100 impacts. From the images, we also measured the volume filling factors of the grown structures, which ranged from 0.15 (uncompacted) to 0.40 (significantly compacted) with increasing impact speed. The velocity dependency of the mass-transfer efficiency and the packing

  3. 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.

  4. 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.

  5. 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.

  6. 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.)

  7. THE ADSORPTION OF STARCHES ON PRESSURE-SENSITIVE ADHESIVE MATERIAL AND ITS IMPACT ON AGGLOMERATION

    Institute of Scientific and Technical Information of China (English)

    Xin Huo; Richard A.Venditti; Houmin Chang

    2004-01-01

    Pressure sensitive adhesive (PSA) particles, or stickies, will self-agglomerate in water with agitation.Under certain conditions, it was found that some starches and Poly-Diallyldimethylammonium Chloride prevent this agglomeration. Both cationic and neutral starches were found to adsorb onto the surface of the negatively charged stickies. This was determined by infra-red spectroscopy, UV spectroscopy, contact angle measurements and charge titration methods. Cationic charge promotes the adsorption of starch onto the surface of stickies and cationic starches adsorbed on the PSA film do not desorb when exposed for 15 minutes to deionized water at room temperature. Cationic starches were found to prevent the agglomeration of stickies at lower concentrations relative to neutral starches.Stickies compete with fibers for the cationic charge in the system. Over the molecular weight (MW)range studied, the MW of the starch has no effect on the prevention of agglomeration of stickies.

  8. Study on Agglomeration and Densification Behaviors of Gadolinium-Doped Ceria Ceramics

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    By synthesizing reactive powders via a self-sustaining combustion synthesis, the glycine-nitrate process, the gadolinium-doped ceria (GDC) with the chemical formula Ce0.8Gd0.2O1.9 was prepared. The resultant powders were dispersed with the terpineol as the dispersant through different methods such as ball milling and high-shear dispersing. Coagulation factor (CF) was used to mark the degree of agglomeration on the nano-scale GDC in this work. The effect of agglomeration on the densification behavior at different sintering temperatures was investigated. The studies indicated that agglomeration retarded the densification at the sintering stage. The powders with better dispersion exhibited a higher sintered density at the same temperature. After effective dispersion treatment, GDC could be fully densified at the sintering temperature of 1300 ℃. The densification temperature was significantly lower than those reported previously. The high sintering kinetics of the ceramics was obtained based on the agglomeration control.

  9. Ash agglomeration during fluidized bed gasification of high sulphur content lignites

    Energy Technology Data Exchange (ETDEWEB)

    Marinov, V.; Marinov, S.P.; Lazarov, L.; Stefanova, M. (SRTI Energydesign, Sofia (Bulgaria))

    1992-09-01

    Intensive ash agglomeration has hampered the fluidized bed gasification of lignites from the Elhovo deposit (Bulgaria) containing 5.9 wt% sulphur in the dry state. Samples of slag and agglomerates from the pilot plant have been examined by means of chemical, X-ray analysis, IR spectroscopy and scanning electron microscopy. Pyrrhotite (FeS) and wustite (FeO) have been established in the agglomerates, where junctions between ash particles have been found to consist of magnetite, spinel and garnet grains. The chemical reactions leading to garnet formation have been studied. Centres of sintering and centres of melting during the ash agglomeration process have been distinguished. The pyrite product, an eutectic of FeS and FeO melting at 924[degree]C, is assumed to be responsible for the cessation of lignite gasification with steam and air under pressure at a bed temperature of 930[degree]. 11 refs., 3 figs., 6 tabs.

  10. 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

  11. 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.

  12. Compactibility of agglomerated mixtures of calcium carbonate and microcrystalline cellulose.

    Science.gov (United States)

    Garzón Serra, María de Lourdes; Villafuerte Robles, Leopoldo

    2003-06-04

    The tablet tensile strength (T) of agglomerated mixtures of microcrystalline cellulose-Avicel PH 102 (MC), calcium carbonate (CC) and polyvinylpyrrolidone (Povidone, PVP), lubricated with magnesium stearate (MS), and formed under a compaction pressure (P(c)) ranging up to 618MPa has been determined. The compactibility was defined through: ln(-ln(1-T/T(max)))=Slope x lnP(c)+Intercept. MC/CC mixtures added of an agglutinant, before and after lubrication, show an important positive effect on their tablet tensile strength compared to a lineal relationship. This positive effect becomes smaller with decreasing compaction pressures. By different mixing methods, the higher the mixing efficiency the higher the compactibility, following the order: spray-dried>wet massing>tumble mixing. The compactibility of MC/CC/PVP spray-dried mixtures with calcium carbonate content from 20 to 60% was equal to or greater than that of pure microcrystalline cellulose. After lubrication with 2% MS the compactibility decreased, only the mixture with the maximal tablet tensile strength attained the tensile strength of pure microcrystalline cellulose. The presence of the binder, the lubricant and higher compaction pressures allow the accommodation of higher calcium carbonate proportions in the mixtures, at the maximal tablet tensile strength of the series. The lubricant decreases in a greater extent the compactibility of mixtures with a continuous phase of MC/PVP than that of CC/PVP. This is attributed to the plastic behavior of the MC/PVP continuous phase compared to a calcium carbonate continuous phase able to disrupt the Povidone and the possible lubricant coatings allowing a stronger interparticle interaction.

  13. Making friends with your neighbors? Agglomeration and tacit collusion in the lodging industry

    OpenAIRE

    Li Gan; Manuel A. Hernandez

    2011-01-01

    Agglomeration is a location pattern frequently observed in service industries such as hotels. This paper empirically examines if agglomeration facilitates tacit collusion in the lodging industry using a quarterly dataset of hotels that operated in rural areas across Texas between 2003 and 2005. We jointly model a price and occupancy rate equation under a switching regression model to endogenously identify a collusive and non-collusive regime. The estimation results indicate that clustered hot...

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

    OpenAIRE

    Cong Xu; Shixin Wang; Yi Zhou; Litao Wang; Wenliang Liu

    2016-01-01

    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 sugg...

  15. Cell agglomeration in the wells of a 24-well plate using acoustic streaming.

    Science.gov (United States)

    Kurashina, Yuta; Takemura, Kenjiro; Friend, James

    2017-02-28

    Cell agglomeration is essential both to the success of drug testing and to the development of tissue engineering. Here, a MHz-order acoustic wave is used to generate acoustic streaming in the wells of a 24-well plate to drive particle and cell agglomeration. Acoustic streaming is known to manipulate particles in microfluidic devices, and even provide concentration in sessile droplets, but concentration of particles or cells in individual wells has never been shown, principally due to the drag present along the periphery of the fluid in such a well. The agglomeration time for a range of particle sizes suggests that shear-induced migration plays an important role in the agglomeration process. Particles with a diameter of 45 μm agglomerated into a suspended pellet under exposure to 2.134 MHz acoustic waves at 1.5 W in 30 s. Additionally, BT-474 cells also agglomerated as adherent masses at the center bottom of the wells of tissue-culture treated 24-well plates. By switching to low cell binding 24-well plates, the BT-474 cells formed suspended agglomerations that appeared to be spheroids, fully fifteen times larger than any cell agglomerates without the acoustic streaming. In either case, the viability and proliferation of the cells were maintained despite acoustic irradiation and streaming. Intermittent excitation was effective in avoiding temperature excursions, consuming only 75 mW per well on average, presenting a convenient means to form fully three-dimensional cellular masses potentially useful for tissue, cancer, and drug research.

  16. 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.

  17. 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.

  18. 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.

  19. Effect of the Additives on the Desulphurization Rate of Flash Hydrated and Agglomerated CFB Fly Ash

    Science.gov (United States)

    Li, D. X.; Li, H. L.; Xu, M.; Lu, J. F.; Liu, Q.; Zhang, J. S.; Yue, G. X.

    CFB fly ash from separators was mixed with water or the mixture of water and additives under the temperature of 363K by use of a blender. Then, this compound of fly ash and water or additives was pumped into a CFB combustion chamber by a sludge pump. Because the temperature of flue gas was high in CFB, the fly ash was hydrated fast and agglomerated in the same time. Through this process, the size of agglomerating fly ash is larger than the original particle and the relative residence time of agglomerated fly ash in CFB becomes longer. Therefore, the rate of utility of calcium in fly ash improves and the content of carbon in fly ash decreases. This results in a low Ca/S and low operational cost for CFB boiler. The additive is one key factor, which affects the rate of desulfurization of agglomerated fly ash. Effect of different additives on rate of desulfurization is not same. Cement and limestone are beneficiated to sulfur removal of agglomerated fly ash, but sodium silicate does not devote to the rate of sulfur removal of agglomerated fly ash.

  20. Developmental research study of coal-fines agglomeration for fixed-bed gasification. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Elmquist, S.A.; Girimont, J.A.; Korosi, F.A.; Kuby, O.A.; Nelson, S.G.; Paulin, M.O.; Peterson, C.A.; Baker, R.L.; Saller, E.

    1983-05-31

    This report presents the results of an intensive program to develop and evaluate agglomerates made from coal fines for use in a fixed-bed gasifier. There were several tasks completed earlier and their results published prior to this final report. These included: Task 1-A, a literature survey of coal agglomeration, binders and techniques used in coal agglomeration, coal and binder treatments and the results of work done by others; Task 1-B, an examination of performance of lump coals in coal gasification, testing and evaluation of the properties of these coals, and evaluation of mine site coal upgrading methods; and Task 1-C/D, a laboratory investigation of coal agglomerates, including wafers, briquettes and pellets, in which the agglomerated coal fines were formed and tested, and the performance of various coal/binder combinations was recorded and evaluated, and factors affecting commercial scale coal agglomeration and gasification were evaluated. These three prior tasks are presented in this report in condensed form.

  1. 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.

  2. 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.)

  3. 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

  4. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Chander, S.; Hogg, R.

    1997-01-15

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

  6. Updates to the dust-agglomerate collision model and implications for planetesimal formation

    Science.gov (United States)

    Blum, Jürgen; Brisset, Julie; Bukhari, Mohtashim; Kothe, Stefan; Landeck, Alexander; Schräpler, Rainer; Weidling, René

    2016-10-01

    Since the publication of our first dust-agglomerate collision model in 2010, several new laboratory experiments have been performed, which have led to a refinement of the model. Substantial improvement of the model has been achieved in the low-velocity regime (where we investigated the abrasion in bouncing collisions), in the high-velocity regime (where we have studied the fragmentation behavior of colliding dust aggregates), in the erosion regime (in which we extended the experiments to impacts of small projectile agglomerates into large target agglomerates), and in the very-low velocity collision regime (where we studied further sticking collisions). We also have applied the new dust-agglomerate collision model to the solar nebula conditions and can constrain the potential growth of planetesimals by mass transfer to a very small parameter space, which makes this growth path very unlikely. Experimental examples, an outline of the new collision model, and applications to dust agglomerate growth in the solar nebula will be presented.

  7. 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.

  8. Development of standards and a cost model for coal agglomeration and related studies

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, S.G.; Kuby, O.A.; Korosi, F.A.; Paulin, M.O.

    1982-02-26

    Several topics concerning coal agglomeration and fixed-bed coal gasification, as they relate to an agglomeration-process development program presently being performed for the Department of Energy, are discussed in this report. Specific topics include an examination of the performance of coals in fixed-bed gasifiers, the development of properties' standards by which agglomerates produced in the program may be compared, the development of a cost model to judge the economic feasibility of coal agglomeration for potential users and the maximum binder levels to be considered in the program, the definition of a suitable briquette size for coal gasification, and a study of upgrading methods at the mines to improve agglomeration. Extensive property data and the results of a number of special tests on six coals (Pittsburgh No. 8 bituminous coal, Illinois No. 6 bituminous coal, Wyoming Bighorn subbituminous coal, Montana Rosebud No. 14 subbituminous coal, North Dakota Indian Head lignite and Pennsylvania Nanoth anthracite coal) and on FMC formcoke and Simplex briquettes are reported.

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

    Science.gov (United States)

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

    2015-07-01

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

  10. 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.

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

    Science.gov (United States)

    Atif, Rasheed; Inam, Fawad

    2016-01-01

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

  12. A Novel Equivalent Agglomeration Model for Heat Conduction Enhancement in Nanofluids

    Science.gov (United States)

    Sui, Jize; Zheng, Liancun; Zhang, Xinxin; Chen, Ying; Cheng, Zhengdong

    2016-01-01

    We propose a multilevel equivalent agglomeration (MEA) model in which all particles in an irregular cluster are treated as a new particle with equivalent volume, the liquid molecules wrapping the cluster and in the gaps are considered to assemble on the surface of new particle as mixing nanolayer (MNL), the thermal conductivity in MNL is assumed to satisfy exponential distribution. Theoretical predictions for thermal conductivity enhancement are highly in agreement with the classical experimental data. Also, we first try to employ TEM information quantitatively to offer probable reference agglomeration ratio (not necessary a very precise value) to just test rational estimations range by present model. The comparison results indicate the satisfactory priori agglomeration ratio estimations range from renovated model. PMID:26777389

  13. 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.

  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. 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.

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

    Directory of Open Access Journals (Sweden)

    Rasheed Atif

    2016-08-01

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

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

    DEFF Research Database (Denmark)

    Mitze, Timo Friedel; Schmidt, Torben Dall

    2015-01-01

    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, endowment......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...... 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 economies...

  18. Study of the temperature evolution of defect agglomerates in neutron irradiated molybdenum single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Lambri, O.A. [Instituto de Fisica Rosario. Member of the CONICET' s Research Staff, Avda. Pellegrini 250, (2000) Rosario, Santa Fe (Argentina); Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Laboratorio de Materiales, Escuela de Ingenieria Electrica, Avda. Pellegrini 250, (2000) Rosario, Santa Fe (Argentina)], E-mail: olambri@fceia.unr.edu.ar; Zelada-Lambri, G.I. [Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Laboratorio de Materiales, Escuela de Ingenieria Electrica, Avda. Pellegrini 250, (2000) Rosario, Santa Fe (Argentina); Cuello, G.J. [Institut Laue Langevin, 6, rue Jules Horowitz, BP 156, 38042 Grenoble (France); Departamento de Fisica Aplicada II, Facultad de Ciencias y Tecnologia, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao, Pais Vasco (Spain); Bozzano, P.B. [Laboratorio de Microscopia Electronica. Unidad de Actividad Materiales, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Avda. Gral. Paz 1499, (1650) San Martin (Argentina); Garcia, J.A. [Departamento de Fisica Aplicada II, Facultad de Ciencias y Tecnologia, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao, Pais Vasco (Spain)

    2009-04-15

    Small angle neutron scattering as a function of temperature, differential thermal analysis, electrical resistivity and transmission electron microscopy studies have been performed in low rate neutron irradiated single crystalline molybdenum, at room temperature, for checking the evolution of the defects agglomerates in the temperature interval between room temperature and 1200 K. The onset of vacancies mobility was found to happen in temperatures within the stage III of recovery. At around 550 K, the agglomerates of vacancies achieve the largest size, as determined from the Guinier approximation for spherical particles. In addition, the decrease of the vacancy concentration together with the dissolution of the agglomerates at temperatures higher than around 920 K was observed, which produce the release of internal stresses in the structure.

  19. Numerical Modelling of Agglomeration and Deagglomeration in Dry Powder Inhalers: A Review.

    Science.gov (United States)

    Yang, Jiecheng; Wu, Chuan-Yu; Adams, Michael

    2015-01-01

    Numerical modelling using computational fluid mechanics (CFD) and discrete element method (DEM) becomes increasingly prevalent for the exploration of agglomeration and deagglomeration in dry powder inhalers (DPIs). These techniques provide detailed information on air flow and particle-particle/wall interaction, respectively. Coupling of CFD and DEM enables an in-depth investigation of the mechanisms at the microscopic level. This paper reviews the applications of CFD and DEM in DPI development and optimisation. The recent progress in modelling of two key processes in DPIs, i.e. agglomeration and deagglomeration, is presented. It has been demonstrated that DEM-CFD is a promising numerical approach to investigate the underlying agglomeration and deagglomeration mechanisms for DPIs. With further advances in computing capacity, it is expected that DEM-CFD will be capable of addressing more realistic and complicated issues in DPI improvement.

  20. Molecular dynamics study of self-agglomeration of charged fullerenes in solvents.

    Science.gov (United States)

    Banerjee, Soumik

    2013-01-28

    The agglomeration of fullerenes in solvents is an important phenomenon that is relevant to controlled synthesis of fullerene-based nanowires as well as fullerene-based composites. The molecular aggregation in solvents depends on the atomistic interactions of fullerene with the solvent and is made complicated by the fact that fullerenes accrue negative surface charges when present in solvents such as water. In the present work, we simulated fullerenes of varying size and shape (C60, C180, C240, and C540) with and without surface charges in polar protic (water), polar aprotic (acetone), and nonpolar (toluene) solvents using molecular dynamics method. Our results demonstrate that uncharged fullerenes form agglomerates in polar solvents such as water and acetone and remain relatively dispersed in nonpolar toluene. The presence of surface charge significantly reduces agglomerate size in water and acetone. Additionally, the relative influence of surface charge on fullerene agglomeration depends on the size and geometry of the fullerene with larger fullerenes forming relatively smaller agglomerates. We evaluated the diffusion coefficients of solvent molecules within the solvation shell of fullerenes and observed that they are much lower than the bulk solvent and are strongly associated with the fullerenes as seen in the corresponding radial distribution functions. To correlate agglomerate size with the binding energy between fullerenes, we evaluated the potential of mean force between fullerenes in each solvent. Consistent with the solubility of fullerenes, binding energy between fullerenes is the greatest in water followed by acetone and toluene. The presence of charge decreases the binding energy of fullerenes in water and thus results in dispersed fullerenes.

  1. 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.

  2. 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.

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

    DEFF Research Database (Denmark)

    Kiil, Søren

    2017-01-01

    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-based....... The 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...

  4. 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.

  5. 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.

  6. Urban agglomerations and transformations of medium-sized towns in Poland

    Directory of Open Access Journals (Sweden)

    Runge Anna

    2016-09-01

    Full Text Available This analysis investigates medium-sized towns in Poland, i.e. those with a population between 20–100 thousand, located up to 100 km away from the main city of the agglomeration. The aim of this article is to compare the level of socio-economic development of Polish towns depending on their location in relation to the main city in the largest agglomerations in 1998 and 2013. Three zones of distance from the main city of each agglomeration have been taken into consideration: a. the inner zone, reaching up to 25 km from the main city; b. the outer zone located at a distance of 25 to 50 km from the main city, and c. the peripheral zone, located at a distance of 50 to 100 km from the main city and including the medium-size towns located outside the agglomeration system. This analysis of the distribution of medium-sized towns and their level of socio-economic development has shown various levels of changes which depend on the distance from the main city of the agglomeration. In 1998, the highest level of development of the medium-sized towns was recorded in towns outside of these agglomeration systems, i.e. those located most remotely from the main city (peripheral zone. Most of the medium-sized towns are situated at a distance of 50–100 km from Warszawa, Kraków, Łódź, Lublin, Gdańsk and have developed their own local, or even regional labour markets and some of them have even provided administrative functions in the past as voivodeship capitals. Only in the Poznań agglomeration, the level of development of medium-sized towns was higher in the immediate surroundings of the main city (25 km. The medium-sized towns in all zones of the distance from the main city in the Wrocław agglomeration represented a similar level of development. By 2013, the level of development of the medium-sized towns in the peripheral zone in all investigated settlement systems had decreased, with a significant improvement in the level of development of the towns in

  7. Evidence that pentosans and xylanase affect the re-agglomeration of the gluten network

    NARCIS (Netherlands)

    Wang, M.; Vliet, T. van; Hamer, R.J.

    2004-01-01

    In the gluten-starch separation process gluten is formed first as a result of breakdown of the gliadin-glutelin structures during mixing followed by their re-agglomeration. To date the effect of pentosans and enzymes have not been studied separately. A simple modification of TNO Glutomatic system en

  8. Biomass ash - bed material interactions leading to agglomeration in fluidised bed combustion and gasification

    Energy Technology Data Exchange (ETDEWEB)

    Visser, H.J.M.; Hofmans, H.; Huijnen, R.; Kastelein, R.; Kiel, J.H.A. [ECN Biomass, Petten (Netherlands)

    2000-07-01

    The present study has been aimed at improving the fundamental understanding of mechanisms underlying agglomeration and defluidisation in fluidised bed combustion and gasification of biomass and waste. To this purpose dedicated lab-scale static heating and fluidisation experiments have been conducted with carefully selected and prepared ashes and bed materials, viz. straw ash/sand and willow ash/sand mixtures, mullite subjected to straw gasification and artificially coated mullite. The main conclusion is that ash/bed material interaction processes are very important and often determine the bed agglomeration and defluidisation tendency. In the static heating experiments with both ash/sand mixtures, partial melting-segregation of ash components and dissolution/reaction with the bed material are processes that determine the melt composition. This melt composition and behaviour can deviate considerably form expectations based on ash-only data. Artificially coated bed materials prove to be very useful for systematic studies on the influence of coating composition and thickness on agglomeration tendency. For the coated mullite samples, different stages in the defluidisation process are identified and the influence of coating properties (thickness, composition, morphology) and operating parameters is elucidated. The behaviour of the mullite appears to be dominated by a remnant glass phase. On the one hand, this glass phase accounts for an alkali-getter capability, while on the other hand it is mainly responsible for agglomeration at temperatures {>=} 800C. 3 refs.

  9. An Agglomeration Law for Sorting Networks and its Application in Functional Programming

    Directory of Open Access Journals (Sweden)

    Lukas Immanuel Schiller

    2017-01-01

    Full Text Available In this paper we will present a general agglomeration law for sorting networks. Agglomeration is a common technique when designing parallel programmes to control the granularity of the computation thereby finding a better fit between the algorithm and the machine on which the algorithm runs. Usually this is done by grouping smaller tasks and computing them en bloc within one parallel process. In the case of sorting networks this could be done by computing bigger parts of the network with one process. The agglomeration law in this paper pursues a different strategy: The input data is grouped and the algorithm is generalized to work on the agglomerated input while the original structure of the algorithm remains. This will result in a new access opportunity to sorting networks well-suited for efficient parallelization on modern multicore computers, computer networks or GPGPU programming. Additionally this enables us to use sorting networks as (parallel or distributed merging stages for arbitrary sorting algorithms, thereby creating new hybrid sorting algorithms with ease. The expressiveness of functional programming languages helps us to apply this law to systematically constructed sorting networks, leading to efficient and easily adaptable sorting algorithms. An application example is given, using the Eden programming language to show the effectiveness of the law. The implementation is compared with different parallel sorting algorithms by runtime behaviour.

  10. Phloem Ultrastructure and Pressure Flow: Sieve-Element-Occlusion-Related Agglomerations Do Not Affect Translocation

    DEFF Research Database (Denmark)

    Froelich, Daniel R.; Mullendore, Daniel L.; Jensen, Kåre Hartvig;

    2011-01-01

    to a discussion about the mode of phloem transport. At present, it is generally agreed that P protein agglomerations are preparation artifacts due to injury, the lumen of sieve tubes is free of obstructions, and phloem flow is driven by an osmotically generated pressure differential according to Münch’s classical...

  11. New surfactant for hydrate anti-agglomeration in hydrocarbon flowlines and seabed oil capture.

    Science.gov (United States)

    Sun, Minwei; Firoozabadi, Abbas

    2013-07-15

    Anti-agglomeration is a promising solution for gas hydrate risks in deepsea hydrocarbon flowlines and oil leak captures. Currently ineffectiveness at high water to oil ratios limits such applications. We present experimental results of a new surfactant in rocking cell tests, which show high efficiency at a full range of water to oil ratios; there is no need for presence of the oil phase. We find that our surfactant at a very low concentration (0.2 wt.% of water) keeps the hydrate particles in anti-agglomeration state. We propose a mechanism different from the established water-in-oil emulsion theory in the literature that the process is effective without the oil phase. There is no need to emulsify the water phase in the oil phase for hydrate anti-agglomeration; with oil-in-water emulsion and without emulsion hydrate anti-agglomeration is presented in our research. We expect our work to pave the way for broad applications in offshore natural gas production and seabed oil capture with very small quantities of an eco-friendly surfactant.

  12. Combination of methanogenesis and denitrification in a UASB reactor for water reclamation applied to small agglomerations

    NARCIS (Netherlands)

    Davila, J.M.S.; Khassab, G.; Klapwijk, A.; Lier, van J.B.

    2009-01-01

    A two-step system combining an anaerobic/anoxic UASB reactor followed by a low energy consuming rotating biological contactor might be a sustainable option for wastewater treatment and reuse in small agglomerations. This article focuses on the UASB stage. The performance of a lab-scale UASB fed with

  13. 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

  14. Agglomeration of Celecoxib by Quasi Emulsion Solvent Diffusion Method: Effect of Stabilizer

    Directory of Open Access Journals (Sweden)

    Maryam Maghsoodi

    2016-12-01

    Full Text Available Purpose: The quasi-emulsion solvent diffusion (QESD has evolved into an effective technique to manufacture agglomerates of API crystals. Although, the proposed technique showed benefits, such as cost effectiveness, that is considerably sensitive to the choice of a stabilizer, which agonizes from a absence of systemic understanding in this field. In the present study, the combination of different solvents and stabilizers were compared to investigate any connections between the solvents and stabilizers. Methods: Agglomerates of celecoxib were prepared by QESD method using four different stabilizers (Tween 80, HPMC, PVP and SLS and three different solvents (methyl acetate, ethyl acetate and isopropyl acetate. The solid state of obtained particles was investigated by differential scanning calorimetry (DSC and Fourier transform infrared (FT-IR spectroscopy. The agglomerated were also evaluated in term of production yield, distribution of particles and dissolution behavior. Results: The results showed that the effectiveness of stabilizer in terms of particle size and particle size distribution is specific to each solvent candidate. A stabilizer with a lower HLB value is preferred which actually increased its effectiveness with the solvent candidates with higher lipophilicity. HPMC appeared to be the most versatile stabilizer because it showed a better stabilizing effect compared to other stabilizers in all solvents used. Conclusion: This study demonstrated that the efficiency of stabilizers in forming the celecoxib agglomerates by QESD was influenced by the HLB of the stabilizer and lipophilicity of the solvents.

  15. STUDY ON THE CHARACTERISTICS OF AGGLOMERATION AND CYCLONE SEPARATION OF DIESEL PARTICULATE

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A particulate separation system that can be used to study the characteristics of the diesel particulate agglomeration and cyclone s eparation is developedIt includes a diesel particulate agglomerator and a cycl one separator mainlyA preliminary investigation on the cyclone separation tech nology for controlling the exhaust particulate from a diesel engine is conducted The experimental results show that the diameter distribution of the diesel par ticulate is changed after they pass through the agglomerator,almost 30%~40% o f the particulate agglomerated from less than 10μm to larger than 10μm ,this change contributes to trap diesel particulateWith this system installed on the exhaust pipe of a singlecylinder engine,the particulate separation effi ciency is around 40%~60% under typical engine running conditionThe backpres sure of this system is less than 5 kPa on full load condition,much less than tha t of other methods of particulate filtrationThis technology has the possibilit y to open a new prospect for particulate reduction because of its simplicity,rel iability and low resistance

  16. Environmental Regulation, Economic Network and Sustainable Growth of Urban Agglomerations in China

    Directory of Open Access Journals (Sweden)

    Zhaohui Chong

    2016-05-01

    Full Text Available In this paper, we examine the influence of environmental regulation on sustainable economic growth from both theoretical and empirical perspectives. Our research is twofold. First, we apply a modified NEG (New Economic Geography model to analyze how environmental regulation influences firms’ location choices and cities’ sustainable economic growth. Second, we test a spatial econometric model employing panel data of the three largest urban agglomerations in China from 2003 to 2013 to study the relationship between environmental regulation and sustainable economic growth as well as the spillover channels of economic activities. The results reveal a remarkable negative effect of environmental regulation on economic growth. In addition, we find no sufficient evidence to prove the existence of long-term effects of environmental regulation on economic growth in the three urban agglomerations. Furthermore, using different weight matrices to illustrate the different economic networks of the urban agglomeration, we validate the difference in spillover mechanisms across these three urban agglomerations. Specifically, the disparity in environmental regulation acts as a spillover channel for the Yangtze River Delta and the Pearl River Delta, while it is not significant for Jing-Jin-Ji.

  17. Morphological and Physicochemical Characterization of Agglomerates of Titanium Dioxide Nanoparticles in Cell Culture Media

    Directory of Open Access Journals (Sweden)

    Verónica Freyre-Fonseca

    2016-01-01

    Full Text Available Titanium dioxide nanoparticles (TiO2 NP are possible carcinogenic materials (2B-IARC and their toxicity depends on shape, size, and electrical charge of primary NP and on the system formed by NP media. The aim of this work was to characterize agglomerates of three TiO2 NP by evaluating their morphometry, stability, and zeta potential (ζ in liquid media and their changes with time. Sizes of agglomerates by dynamic light scattering (DLS resulted to be 10–50 times larger than those obtained by digital image analysis (DIA given the charged zone around particles. Fractal dimension (FD was highest for agglomerates of spheres and belts in F12K, and in E171 in FBS media. E171 and belts increased FD with time. At time zero, using water as dispersant FD was larger for agglomerates of spheres than for of E171. Belts suspended in water had the smallest values of circularity (Ci which was approximately unchanged with time. All dispersions had ζ values around −30 mV at physiological pH (7.4 and dispersions of NP in water and FBS showed maximum stability (Turbiscan Lab analysis. Results help in understanding the complex NP geometry-size-stability relationships when performing in vivo and in vitro environmental-toxicity works and help in supporting decisions on the usage of TiO2 NP.

  18. THE INFLUENCE OF LOGISTICS OVER THE OCCURRENCE OF SPATIAL AGGLOMERATION OF BUSINESSES

    Directory of Open Access Journals (Sweden)

    MĂDĂLINA S. MATICIUC

    2015-04-01

    Full Text Available This paper involves an examination of the literature that refers to the various methods of spatial agglomeration of businesses where the focus is actually minimizing transportation costs. The research has a predominantly theoretical nature, based on exploratory method, being focused on the literature review to highlight the evolution of different forms of spatial organization so we can identify the advantages of acquiring further knowledge needed to the applied research, providing in this manner prospects for progress. The vicinity of the representatives of the economic, political and educational environment presents many advantages with regard to reciprocal relationships that can develop within these, whether formal or informal, highlighting the potential of flexible innovative forms of spatial organization of clusters. Spatial agglomeration theories that were developed in the course of time, is a cornerstone for new innovative forms of business spatial organization such as clusters and networks of clusters that are offering many advantages in terms of cost of transportation. The evolution of business spatial agglomerations shows that the vast majority of companies aim to ensure competitive advantage not only in close locations to increase the generation of innovation and reduced transport costs, but also through access to knowledge in a fast and easy way. The work comes in support of these ideas , proposing in the conclusions part a new model of business agglomeration which does not require physical proximity but one of cloud type.

  19. 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.

  20. 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.

  1. Conversion of biomass, prediction and solution methods for ash agglomeration and related problems

    Energy Technology Data Exchange (ETDEWEB)

    Van der Drift, A. [ECN Fuels Conversion and Environment, Petten (Netherlands); Olsen, A. [Risoe, Roskilde (Denmark)

    1999-11-01

    When biomass is used as fuel for thermal conversion plants, minerals from the fuel can be responsible for major problems. Generally, these problems are associated with the existence and development of low melting compounds or eutectics, which form sticky layers. In a fluidised bed, this can result in bed-agglomeration and defluidisation. This causes local high temperature, which often accelerates the process. It ultimately can lead to a completely sintered bed content with a glassy phase gluing the bed particles together and shut-down of the plant. The main objective of the title project is to develop a methodology to predict ash/bed agglomeration and sintering problems, to indicate related problems and, furthermore, to identify solution methods to make different types of biomass streams more viable for energy production. Within the present study, selected fuels are subjected to different existing methods together with some new ones, in order to determine the agglomeration temperature. The selected fuels are verge grass, Danish wheat straw (both stored dry and partly leached due to rainfall), sewage sludge, cacao shells and willow as a reference. The methods used within the study are chemical analysis of fuel and ashes, determination of standard ash melting temperatures, compression strength measurements of the ash, DTA/TG analysis of the ash, SEM and ESEM (high temperature environmental scanning microscopy), two different lab-scale bubbling fluidised bed combustion facilities, a lab-scale bubbling fluidised bed gasifier and a circulating fluidised bed gasifier. The lab-scale facilities have been used to test potential measures to reduce the problem of agglomeration. These measures are the use of additives (kaolin, magnesite, dolomite, gibbsite and sewage sludge) and non-quartz bed materials (alumina and mullite). The work performed within the project has lead to the following results. Chemical analysis of the fuel can give a first indication of whether there might

  2. Evaluation of charge and agglomeration behavior of TiO₂ nanoparticles in ecotoxicological media.

    Science.gov (United States)

    Nur, Y; Lead, J R; Baalousha, M

    2015-12-01

    The dynamic nature of nanoparticle (NP) agglomeration behavior is of paramount interest to many current studies in environmental nanoscience and nano(eco)toxicology because agglomeration affects the NP bioavailability and toxicity. The present study investigates the surface charge and agglomeration behavior of TiO2 NPs in four different ecotoxicological media (OECD algae, OECD L_variegatus, hardwater and plant media) and two different electrolytes KCl (200 mM) and CaCl2 (50 mM). TiO2 NPs were positively charged, and the zeta potential varied from +1.9 mV in hardwater (at pH7.1) to +24.5 mV in CaCl2 electrolyte (at pH7.4) in all media except algae media, where the zeta potential was -6.7 mV (at pH7.7). Despite the differences in the pH and the surface charge of TiO2 NPs in the different media, an immediate agglomeration of the NPs in all standard ecotoxicological media was observed with aggregate sizes in the micrometer scale, as the measured zeta potentials were insufficient to prevent TiO2 NP agglomeration. The isoelectric point (pHiep) of TiO2 NPs in the studied media varied in the range (6.8-7.6), which was attributed to preferential association of anions and cations to TiO2; that is the pHiep decreases with the increased concentration of Cl and increases with the increased concentrations of Na and Mg. Despite the complexity of the ecotoxicological media and the presence of a mixture of different monovalent and divalent electrolytes, the agglomeration kinetics in the media follows the DVLO theory where two distinct agglomeration rates (slow, reaction limited regime and fast, diffusion limited regime) were observable. The critical coagulation concentration (CCC) of TiO2 NPs in the ecotoxicological media varied from 17.6 to 54.0% v/v standard media in UHPW, due to differences in media pH and TiO2 NP surface charge. In the ecotoxicological media (hardwater, L-variegatus and plant), where TiO2 NPs are positively charged, the CCC decrease with the increased divalent

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

    Directory of Open Access Journals (Sweden)

    Cassee Flemming R

    2010-12-01

    Full Text Available Abstract Background Nanoparticle (NP toxicity testing comes with many challenges. Characterization of the test substance is of crucial importance and in the case of NPs, agglomeration/aggregation state in physiological media needs to be considered. In this study, we have addressed the effect of agglomerated versus single particle suspensions of nano- and submicron sized gold on the inflammatory response in the lung. Rats were exposed to a single dose of 1.6 mg/kg body weight (bw of spherical gold particles with geometric diameters of 50 nm or 250 nm diluted either by ultrapure water or by adding phosphate buffered saline (PBS. A single dose of 1.6 mg/kg bw DQ12 quartz was used as a positive control for pulmonary inflammation. Extensive characterization of the particle suspensions has been performed by determining the zetapotential, pH, gold concentration and particle size distribution. Primary particle size and particle purity has been verified using transmission electron microscopy (TEM techniques. Pulmonary inflammation (total cell number, differential cell count and pro-inflammatory cytokines, cell damage (total protein and albumin and cytotoxicity (alkaline phosphatase and lactate dehydrogenase were determined in bronchoalveolar lavage fluid (BALF and acute systemic effects in blood (total cell number, differential cell counts, fibrinogen and C-reactive protein 3 and 24 hours post exposure. Uptake of gold particles in alveolar macrophages has been determined by TEM. Results Particles diluted in ultrapure water are well dispersed, while agglomerates are formed when diluting in PBS. The particle size of the 50 nm particles was confirmed, while the 250 nm particles appear to be 200 nm using tracking analysis and 210 nm using TEM. No major differences in pulmonary and systemic toxicity markers were observed after instillation of agglomerated versus single gold particles of different sizes. Both agglomerated as well as single nanoparticles were

  4. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-12-31

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

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

    Science.gov (United States)

    Ao, Wen; Liu, Peijin; Yang, Wenjing

    2016-12-01

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

  8. Simulation of Solid Particle Agglomeration Process in Gas Enhanced by High Intensity Sound Field%Simulation of Solid Particle Agglomeration Process in Gas Enhanced by High Intensity Sound Field

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    There are two mechanisms in the particle agglomeration process enhanced by the high intensity sound field in the gas-solid system: the orthokinetic interaction mechanism and hydrodynamic interaction mechanism. The orthokinetic interaction mechanism, hydrodynamic interaction mechanism and the acoustic agglomeration process which included the both two mechanisms were investigated by modeling method and MATLAB program. The results showed: the value of acoustic agglomeration kernel function (AAKF) based on the orthokinetic interaction mechanism was zero when the size of two particles in the pair was the same.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zook, Justin M., E-mail: jzook@nist.gov; Halter, Melissa D.; Cleveland, Danielle; Long, Stephen E. [National Institute of Standards and Technology, Material Measurement Laboratory (United States)

    2012-10-15

    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 {approx}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{sup +} 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.

  10. In Situ Observations of Interaction Between Particulate Agglomerates and an Advancing Planar Solid/Liquid Interface: Microgravity Experiments

    Science.gov (United States)

    Sen, S.; Juretzko, F.; Stafanescu, D. M.; Dhindaw, B. K.; Curreri, P. A.

    1999-01-01

    Results are reported of directional solidification experiments on particulate agglomerate pushing and engulfment by a planar solid/liquid (s/l) interface. These experiments were conducted on the Space Shuttle Columbia during the United States Microgravity Payload 4 (USMP-4) Mission. It was found that the pushing to engulfment transition velocity, V(sub cr) for agglomerates depends not only on their effective size but also their orientation with respect to the s,1 interface. The analytical model for predicting V(sub cr) of a single particle was subsequently enhanced to predict V(sub cr) of the agglomerates by considering their shape factor and orientation.

  11. In-Situ Observations of Interaction Between Particulate Agglomerates and an Advancing Planar Solid/Liquid Interface: Microgravity Experiments

    Science.gov (United States)

    Sen, S.; Juretzko, F.; Stefanescu, D. M.; Dhindaw, B. K.; Curreri, P. A.

    1999-01-01

    Results are reported of directional solidification experiments on particulate agglomerate pushing and engulfment by a planar solid/liquid (s/1) interface. These experiments were conducted on the Space Shuttle Columbia during the United States Microgravity Payload 4 (USMP-4) Mission. It was found that the pushing to engulfment transition velocity, V(sub ct),, for agglomerates depends not only on their effective size but also their orientation with respect to the s/l interface. The analytical model for predicting V(sub cr) of a single particle was subsequently enhanced to predict V(sub cr) of the agglomerates by considering their shape factor and orientation.

  12. Biomass-Ash-Induced Agglomeration in a Fluidized Bed. Part 1: Experimental Study on the Effects of a Gas Atmosphere

    DEFF Research Database (Denmark)

    Ma, Teng; Fan, Chuigang; Hao, Lifang

    2016-01-01

    Fluidized beds have been widely applied to gasification and combustion of biomass. During gasification, a high temperature is preferable to increase the carbon conversion and to reduce the undesirable tar. However, the high temperature may lead to a severe agglomeration problem in a fluidized bed....... Understanding of the agglomeration in various atmospheres is crucial to optimize the design and operation conditions. This study focuses on the effects of gases on agglomeration tendency with different types of biomass, including corn straw, rice straw, and wheat straw. The biomass ash samples are mixed...

  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. 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.

  15. Sonic enhanced ash agglomeration and sulfur capture. Technical progress report: January 1993--March 1993

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-31

    This 15th Quarterly Technical Progress Report presents the results of work accomplished during the period January 4, 193 through March 28, 1993 under Contract No. DE-AC21-88MC26288 entitled {open_quotes}Sonic Enhanced Ash Agglomeration and Sulfur Capture.{close_quotes} The fundamental studies conducted by West Virginia University and Pennsylvania State University are provided in subsections of this report. Shakedown testing continued through this period resulting in a series of required modifications for the coal-feed system, coal injector, installation of a water-cooling jacket at the bottom of the agglomeration chamber, and finally, the installation of an additional flow sensor and rate meter. Coal-fired bimodal tests were initiated at the end of the period. The unit was run at 2 atm pressure for 3 hours with steady-state operation for 2 hours. Then, the pressure was increased to 3 atm with steady-state operation for 2 hours.

  16. Remediation of oil-contaminated sand by coal agglomeration using ball milling.

    Science.gov (United States)

    Shin, Yu-Jen; Shen, Yun-Hwei

    2011-10-01

    The mechanical shear force provided by a less energy intensive device (usually operating at 20-200 rpm), a ball mill, was used toperform coal agglomeration and its effects on remediation of a model fuel oil-contaminated sand were evaluated. Important process parameters such as the amount of coal added, milling time, milling speed and the size of milling elements are discussed. The results suggested that highly hydrophobic oil-coal agglomerates, formed by adding suitable amounts of coal into the oil-contaminated sand, could be mechanically liberated from cleaned sand during ball milling and recovered as a surface coating on the steel balls. Over 90% removal of oil from oil-contaminated sand was achieved with 6 wt% of coal addition and an optimum ball milling time of 20 min and speed of 200 rpm. This novel process has considerable potential for cleaning oil-contaminated sands.

  17. 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...

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

    Directory of Open Access Journals (Sweden)

    Asim Iqba

    2013-05-01

    Full Text Available 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 plays a vital role in determining the productivity of establishments. The impact of localization (specialization is positive and stronger than urbanization (diversification which implies that locating manufacturing establishments in a particular district leads to enhance the productivity of establishments. Therefore, government policy should be biased to promote localization of textile and leather industry.

  19. 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......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...... describes a fundamental study on the mechanisms of defluidization. For the studied process of bed defluidization due to sintering of grain-coating layers, it was found that the onset of the process depends on (a) a critical coating thickness, (b) on the fluidization velocity when it is below approximately...... four times the minimum fluidization velocity, and (c) on the viscosity (stickiness) of the outside of the grains (coating)....

  20. 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.

  1. Assessment of Urban Ecosystem Health Based on Entropy Weight Extension Decision Model in Urban Agglomeration

    OpenAIRE

    Qian Yang; Aiwen Lin; Zhenzhen Zhao; Ling Zou; Cheng Sun

    2016-01-01

    Urban ecosystem health evaluation can assist in sustainable ecological management at a regional level. This study examined urban agglomeration ecosystem health in the middle reaches of the Yangtze River with entropy weight and extension theories. The model overcomes information omissions and subjectivity problems in the evaluation process of urban ecosystem health. Results showed that human capital and education, economic development level as well as urban infrastructure have a significant ef...

  2. Nucleation, wetting and agglomeration of copper and copper-alloy thin films on metal liner surfaces

    Science.gov (United States)

    LaBarbera, Stephanie Florence

    One of the key challenges in fabricating narrower and higher aspect ratio interconnects using damascene technology has been achieving an ultra-thin (˜2 nm) and continuous Cu seed coverage on trench sidewalls. The thin seed is prone to agglomeration because of poor Cu wetting on the Ta liner. Using in-situ conductance measurements, the effect of lowering the substrate temperature during Cu seed deposition has been studied on tantalum (Ta) and ruthenium (Ru) liner surfaces. On a Ta surface, it was found that lowering the deposition temperature to --65°C increases the nucleation rate of the Cu thin film, and reduces the minimum coalescing thickness for Cu on Ta liner from ˜4.5 nm (at room temperature) to ˜2 nm. On a Ru surface, Cu coalesces at wetting angle, coalescing thickness, and agglomeration resistance of thin Cu-3% Au, Cu-3% Mn, and Cu-3% Al layers on a Ta liner surface have been studied. It was found that the alloying increases the wetting angle of Cu on Ta at high temperature, as a result of either reduction in Cu alloy surface energy, solute surface segregation, or solute-liner interactions. In addition, the Cu alloys were found to be less agglomeration resistive as compared to pure Cu; their smaller grain size, interaction with the liner surface, and tendency to oxidize were found to accelerate their agglomeration. The coalescing thickness of the Cu alloys was found to be reduced from that of Cu (˜4.5 nm) to ˜2 nm.

  3. Agglomeration Economies, Economic Growth and the New Economic Geography in Mexico

    OpenAIRE

    Alejandro Diaz-Bautista

    2005-01-01

    The present study of regional economic growth in Mexico is based on the new economic geography, where distance plays an important role in explaining urban regional economic growth. The results show that distance to the northern border of Mexico and labor migration between states of Mexico, after the passage of NAFTA are important factors that explain the regional state growth and agglomerations in Mexico between 1994 and 2000. The results also indicate that job growth and FDI are not signific...

  4. Control of nanoparticle agglomeration through variation of the time-temperature profile in chemical vapor synthesis

    Science.gov (United States)

    Djenadic, Ruzica; Winterer, Markus

    2017-02-01

    The influence of the time-temperature history on the characteristics of nanoparticles such as size, degree of agglomeration, or crystallinity is investigated for chemical vapor synthesis (CVS). A simple reaction-coagulation-sintering model is used to describe the CVS process, and the results of the model are compared to experimental data. Nanocrystalline titania is used as model material. Titania nanoparticles are generated from titanium-tetraisopropoxide (TTIP) in a hot-wall reactor. Pure anatase particles and mixtures of anatase, rutile (up to 11 vol.%), and brookite (up to 29 vol.%) with primary particle sizes from 1.7 nm to 10.5 nm and agglomerate particle sizes from 24.3 nm to 55.6 nm are formed depending on the particle time-temperature history. An inductively heated furnace with variable inductor geometry is used as a novel system to control the time-temperature profile in the reactor externally covering a large wall temperature range from 873 K to 2023 K. An appropriate choice of inductor geometry, i.e. time-temperature profile, can significantly reduce the degree of agglomeration. Other particle characteristics such as crystallinity are also substantially influenced by the time-temperature profile.

  5. Assessment of Urban Ecosystem Health Based on Entropy Weight Extension Decision Model in Urban Agglomeration

    Directory of Open Access Journals (Sweden)

    Qian Yang

    2016-08-01

    Full Text Available Urban ecosystem health evaluation can assist in sustainable ecological management at a regional level. This study examined urban agglomeration ecosystem health in the middle reaches of the Yangtze River with entropy weight and extension theories. The model overcomes information omissions and subjectivity problems in the evaluation process of urban ecosystem health. Results showed that human capital and education, economic development level as well as urban infrastructure have a significant effect on the health states of urban agglomerations. The health status of the urban agglomeration’s ecosystem was not optimistic in 2013. The majority of the cities were unhealthy or verging on unhealthy, accounting for 64.52% of the total number of cities in the urban agglomeration. The regional differences of the 31 cities’ ecosystem health are significant. The cause originated from an imbalance in economic development and the policy guidance of city development. It is necessary to speed up the integration process to promote coordinated regional development. The present study will aid us in understanding and advancing the health situation of the urban ecosystem in the middle reaches of the Yangtze River and will provide an efficient urban ecosystem health evaluation method that can be used in other areas.

  6. Relationship Between Social Economic Agglomeration and Labor Productivity of Core Cities in Northeast China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Peng; YANG Qingshan; ZHAO Yichun

    2012-01-01

    Dalian,Shenyang,Changchun and Harbin are the four core cities which play an essential role in terms of promoting the economic development in Northeast China.In this paper,the impact of urban agglomeration on labor productivity is explored by making comparisons among these four cities.The model used for analysis is a classical model derived from previous studies.Some indicators,such as population density and economic density,were selected to examine the impact of urban agglomeration on the labor productivity based on the time-series data for the four cities from 1990 to 2007.The four main conclusions are:1) The promotion from the growth rate of population density on the growth rate of labor productivity is limited.2) The negative relationship exists between the growth rate of employment density and the growth rate of labor productivity.3) Agglomeration effect exists in the four cities,the highest one is Dalian,Shenyang takes the second place,followed by Changchun and Harbin,and the predominant promotion exerted on the labor productivity is the output density.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-01-01

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

  8. 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.

  9. Gasification of palm empty fruit bunch in a bubbling fluidized bed: a performance and agglomeration study.

    Science.gov (United States)

    Lahijani, Pooya; Zainal, Zainal Alimuddin

    2011-01-01

    Gasification of palm empty fruit bunch (EFB) was investigated in a pilot-scale air-blown fluidized bed. The effect of bed temperature (650-1050 °C) on gasification performance was studied. To explore the potential of EFB, the gasification results were compared to that of sawdust. Results showed that maximum heating values (HHV) of 5.37 and 5.88 (MJ/Nm3), dry gas yield of 2.04 and 2.0 (Nm3/kg), carbon conversion of 93% and 85 % and cold gas efficiency of 72% and 71 % were obtained for EFB and sawdust at the temperature of 1050 °C and ER of 0.25. However, it was realized that agglomeration was the major issue in EFB gasification at high temperatures. To prevent the bed agglomeration, EFB gasification was performed at temperature of 770±20 °C while the ER was varied from 0.17 to 0.32. Maximum HHV of 4.53 was obtained at ER of 0.21 where no agglomeration was observed.

  10. Behavior of Polyamine Fixing Agents on Agglomeration of Dissolved and Colloidal Substances in Papermaking

    Directory of Open Access Journals (Sweden)

    Yiqian Zhang

    2013-11-01

    Full Text Available Five polyamine fixing agents with different molecular weights but slightly different charge densities were used to treat a deinked pulp. Their efficacy in controlling colloidal substances (CS in the pulp was measured using focused beam reflectance measurements (FBRM. The objective was to determine if the colloidal substances were affected by the fixing agents by a “colloidal fixation” mechanism, i.e., colloidal particles being fixed onto pulp fiber in an un-agglomerated, single-particle state, or a “colloidal agglomeration” one, i.e., colloidal particles being coagulated by fixing agents into bigger agglomerates. The results showed that colloidal fixation does take place, especially for the polyamine with the smallest molecular weight. Among the five polyamines, it was found that higher molecular weights tended to result in more extensive colloidal agglomeration, but the effect of charge density was almost insignificant. Because it is efficient in differentiating between these two fixation mechanisms, FBRM is a powerful tool in screening different fixing agents.

  11. A 3D hybrid grid generation technique and a multigrid/parallel algorithm based on anisotropic agglomeration approach

    Institute of Scientific and Technical Information of China (English)

    Zhang Laiping; Zhao Zhong; Chang Xinghua; He Xin

    2013-01-01

    A hybrid grid generation technique and a multigrid/parallel algorithm are presented in this paper for turbulence flow simulations over three-dimensional (3D) complex geometries.The hybrid grid generation technique is based on an agglomeration method of anisotropic tetrahedrons.Firstly,the complex computational domain is covered by pure tetrahedral grids,in which anisotropic tetrahedrons are adopted to discrete the boundary layer and isotropic tetrahedrons in the outer field.Then,the anisotropic tetrahedrons in the boundary layer are agglomerated to generate prismatic grids.The agglomeration method can improve the grid quality in boundary layer and reduce the grid quantity to enhance the numerical accuracy and efficiency.In order to accelerate the convergence history,a multigrid/parallel algorithm is developed also based on anisotropic agglomeration approach.The numerical results demonstrate the excellent accelerating capability of this multigrid method.

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

    Institute of Scientific and Technical Information of China (English)

    XU Xiangde; SHI Xiaohui; ZHANG Shengjun; DING Guoan; MIAO Qiuju; ZHOU Li

    2006-01-01

    The aerosol distribution in Beijing and peripheral cities agglomeration (BPCA) and its regional climatic effect are investigated on the basis of the statistical analyses of satellite Total Ozone Mapping Spectrometer (TOMS) retrieval aerosol optical depth (AOD) and the meteorological data of sunshine duration, fog days, and low cloud cover, observed at Beijing and its peripheral meteorological stations. The analysis on multi-samples variational correction of the satellite remote sensing Moderate Resolution Imaging Spectroradiometer (MODIS) AOD under the clear sky and stable weather condition in conjunction with surface observations reveal that there was a "triangle-like" distribution pattern of the high values of aerosols in the southern "valley" of the "U-shape"megarelief of Beijing and its peripheral areas. The distribution pattern suggests that the large-scale transfer and diffusion of city agglomeration pollutants might form a relatively persistent characteristic spatial distribution of city agglomeration pollutants much larger than city-scale. Under the background of the particular megarelief effect of Beijing and peripheral areas, the high value area of TOMS AOD, as well as regional correlation distribution between clear sky sunshine duration and TOMS AOD are also similar to the composite image of MODIS AOD variational fields,that is to say, the effect of atmospheric aerosols was very distinctive in Beijing and peripheral areas. The high value area of the negative correlation between clear sky sunshine duration and TOMS AOD approximately accorded with the significant negative value area of the sunshine duration deviations of the 1980s to the 1990s, and the daily variations of the AOD also showed an anti-phase relation with those of clear sky sunshine duration. The above high correlation area of the urban aerosol impact of Beijing-Tianjin region leant towards south peripheral area,with its "center of gravity" in the south of Beijing-Tianjin agglomeration, and

  13. The self-preserving size distribution theory. I. Effects of the Knudsen number on aerosol agglomerate growth.

    Science.gov (United States)

    Dekkers, Petrus J; Friedlander, Sheldon K

    2002-04-15

    Gas-phase synthesis of fine solid particles leads to fractal-like structures whose transport and light scattering properties differ from those of their spherical counterparts. Self-preserving size distribution theory provides a useful methodology for analyzing the asymptotic behavior of such systems. Apparent inconsistencies in previous treatments of the self-preserving size distributions in the free molecule regime are resolved. Integro-differential equations for fractal-like particles in the continuum and near continuum regimes are derived and used to calculate the self-preserving and quasi-self-preserving size distributions for agglomerates formed by Brownian coagulation. The results for the limiting case (the continuum regime) were compared with the results of other authors. For these cases the finite difference method was in good in agreement with previous calculations in the continuum regime. A new analysis of aerosol agglomeration for the entire Knudsen number range was developed and compared with a monodisperse model; Higher agglomeration rates were found for lower fractal dimensions, as expected from previous studies. Effects of fractal dimension, pressure, volume loading and temperature on agglomerate growth were investigated. The agglomeration rate can be reduced by decreasing volumetric loading or by increasing the pressure. In laminar flow, an increase in pressure can be used to control particle growth and polydispersity. For D(f)=2, an increase in pressure from 1 to 4 bar reduces the collision radius by about 30%. Varying the temperature has a much smaller effect on agglomerate coagulation.

  14. Agglomeration Rents,Policy Rents and Agglomeration Mechanism:Study on Science and Technology Service Industries%集聚租、政策租与产业集聚:基于科技服务业的研究

    Institute of Scientific and Technical Information of China (English)

    钟小平

    2014-01-01

    促进科技服务业集聚的机制可分解为市场机制和政策机制,前者为产业集群内的企业提供集聚租,后者提供政策租。集聚租和政策租都能显著地促进科技服务业的产业集聚,集聚租和政策租在产业集聚的不同过程中发挥着不同的作用,基于市场机制的集聚租能够对科技服务业的集聚产生长久效应,而基于政策机制以获得政策租是促进科技服务企业进驻集群的短期诱因。%Relying on the relevant theory of industry organization and space economics,this paper aims at explaining the motives for the growing self-reinforcement of industry spatial agglomeration. Based on this, the stimulus factors of S&T service industrial agglomeration can be divided into market mechanism and policy mechanism. Correspondingly,the objective of the agglomeration of S&T service industry is to obtain the“ag-glomeration rent”and“policy rent”provided by industry cluster. The results show that,the effect of“policy rent”and“agglomeration rent”on S&T service industrial agglomeration is obvious. In the long term,the effect of“agglomeration rent”on S&T service industrial agglomeration is greater than that of“policy rent”.

  15. 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.

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

    Directory of Open Access Journals (Sweden)

    Kuznetsov S. V.

    2014-03-01

    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.

  17. A Comparative Study on Changes in the Spatial Industry Agglomeration in Eastern EU Developing Countries: Romania vs. Bulgaria

    Directory of Open Access Journals (Sweden)

    Madalina-Stefania Dirzu

    2013-08-01

    Full Text Available Taking a closer look at the spatial distribution of industrial sectors, it becomes quite obvious that there is an increasing disposition for industries to concentrate in certain regions in order to benefit of agglomeration assets. In this context, we consider necessary to analyze how industrial agglomerations have evolved over time and to what extent major transformations have affected agglomeration phenomenon in lagging regions of Eastern countries, finally our paper bringing supportive evidence from Romania and Bulgaria. To what extent, have patterns of industrial agglomeration modified during the transition period? Has relocation of economic activities taken place? What are the main determinants of industrial concentration patterns? These are some crucial questions that we try to find a realistic response through the present paper. Eastern economies are notably challenging from this point of view because they experienced several decades long economic development period which was earmarked by socialist industrialization. Under the planned economy, these countries have faced more barriers to an efficient geographical allocation of economic activities across regions than their peers in the Western Europe especially because they faced the legacy of a planned economy system that determined locations for economic activities based on political decisions, not based on economic efficiency. Thus, our effort can be seen as a contribution to knowledge about agglomeration in the non-Western countries in general, and in developing regions in particular. Focusing our study on two-digit industrial sectors of 14 regions at NUTS2 level, this paper aims to identify and explain the changes regarding the evolution of industrial agglomerations in the last years across Romania compared to Bulgaria. In the end, our analysis will be able to conclude in what manner the effects of transition period influenced the patterns of industrial agglomeration in these two

  18. 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.

  19. Laser-induced agglomeration of gold and silver nanoparticles dispersed in liquid

    Science.gov (United States)

    Serkov, A. A.; Kuzmin, P. G.; Shafeev, G. A.

    2016-03-01

    Evolution of size distribution function, morphology, and extinction spectra of Ag nanoparticles and Au-Ag nanoparticles mixture dispersed in liquids under picosecond laser exposure are experimentally studied. It is shown that picosecond laser exposure of dense aqueous solutions of NPs (above 1014 particles per ml) leads to formation of elongated agglomerates. Time dependence of the size distribution function is monitored during irradiation process and compared to optical spectra and Transmission Electron Microscope images. Exposure of Au-Ag nanoparticles mixture is shown to result in formation of NPs chains consisting of Au and Ag, or Au-Ag alloy NPs.

  20. Influence of the nanoparticles agglomeration state in the quantum-confinement effects: Experimental evidences

    Directory of Open Access Journals (Sweden)

    I. Lorite

    2015-03-01

    Full Text Available The agglomeration state facilitates particle-particle interaction which produces important effects in the phonon confinement effects at the nanoscale. A partial phonon transmission between close nanoparticles yields a lower momentum conservation relaxation than in a single isolated nanoparticle. It means a larger red shift and broadening of the Raman modes than the expected ones for Raman quantum confinement effects. This particle-particle interaction can drive to error when Raman responses are used to estimate the size of the nanoscaled materials. In this work different corrections are suggested to overtake this source of error.

  1. 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.

  2. Influence of the nanoparticles agglomeration state in the quantum-confinement effects: Experimental evidences

    Energy Technology Data Exchange (ETDEWEB)

    Lorite, I., E-mail: lorite@physik.uni-leipzig.de [Electroceramic Department, Instituto de Cerámica y Vidrio, CSIC, Kelsen 5, 28049, Madrid (Spain); Division of Superconductivity and Magnetism, Faculty of Physics and Earth Sciences, Linnestrasse 5, D-04103 Leipzig (Germany); Romero, J. J.; Fernandez, J. F. [Electroceramic Department, Instituto de Cerámica y Vidrio, CSIC, Kelsen 5, 28049, Madrid (Spain)

    2015-03-15

    The agglomeration state facilitates particle-particle interaction which produces important effects in the phonon confinement effects at the nanoscale. A partial phonon transmission between close nanoparticles yields a lower momentum conservation relaxation than in a single isolated nanoparticle. It means a larger red shift and broadening of the Raman modes than the expected ones for Raman quantum confinement effects. This particle-particle interaction can drive to error when Raman responses are used to estimate the size of the nanoscaled materials. In this work different corrections are suggested to overtake this source of error.

  3. 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...... affects the particle size distribution of Mg(OH)2 (used as model material) as well as silica, whereas the addition of superplasticizers affects only the smallest particles in cement and thus primarily acts as water reducers and not dispersers....

  4. Study on agglomeration-collected magnetic separation of ink%油墨的凝聚-磁选研究

    Institute of Scientific and Technical Information of China (English)

    郑其; 车小奎; 陈松; 陈伟东

    2011-01-01

    Agglomeration and magnetic separation of ink are investigated in the paper. Magnetite, sodium oleate and kerosene were added in waste ink pulp, which holds magnetite and nonmagnetic ink together through hydrophobic agglomeration. The agglomerates were then recovered through magnetic separation. The study indicates that sodium oleate and kerosene as the agglomeration reagents are the premise and guarantee for agglomeration of magnetite and ink, and magnetite as the magnetic seed ensures the magnetism of the agglomerate that can be used for magnetic separation. Ink agglomerate size and magnetism increased as a result of agglomeration. Ink recovery in magnetic product is 84.09%, when the experiment conditions are the ink density of 20% ,magnetite dosage of 2 g/L,sodium oleate dosage of 3 g/L, and kerosene dosage of 3 g/L, pH = 9,the agglomeration stir time of 20 min and the magnetic field intensity of 1 T.%进行了油墨凝聚、磁选的研究,在废油墨中添加磁铁矿、油酸钠和煤油,使磁铁矿和非磁性油墨通过疏水性凝聚粘附在一起,再用磁选回收.研究表明,油酸钠和煤油作为凝聚剂是磁铁矿与油墨凝聚的前提和保证,磁种磁铁矿的加入确保了聚团的磁性能用于磁选.凝聚增大油墨聚团粒度和磁性.在油墨浓度为200g/L、磁铁矿用量2g/L、油酸钠用量为3g/L、煤油用量3g/L、pH=9、凝聚搅拌时间20 min和磁场强度为1 T的条件下,油墨在磁性产品中的回收率为84.09%.

  5. 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.

  6. 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.

  7. Nano-sized Mn oxide/agglomerated silsesquioxane composite as a good catalyst for water oxidation.

    Science.gov (United States)

    Najafpour, Mohammad Mahdi; Madadkhani, Sepideh

    2016-12-01

    Water splitting to hydrogen and oxygen is an important reaction to store sustainable energies, and water oxidation is identified as the bottleneck for water splitting because it requires the high activation energy to perform. Herein a nano-sized Mn oxide/agglomerated silsesquioxane composite was used to synthesize an efficient catalyst for water oxidation. The composite was synthesized by a straightforward and simple procedure and characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, dynamic light scattering, X-ray diffraction spectrometry, and electrochemical methods. Silsesquioxane causes good dispersion of Mn in the composite. The water-oxidizing activity of this composite was studied in the presence of cerium(IV) ammonium nitrate. The composite at the best calcination temperature (300 °C) shows a turnover frequency 0.3 (mmol O2/mol Mn.s). Regarding the low-cost, environmentally friendly precursors, simple synthesis, and efficiency for water oxidation, the composite is a promising catalyst that can be used in artificial photosynthetic systems for water splitting. We used Agglomerated silsesquioxane as a support for nano-sized Mn oxide to synthesize a good water-oxidizing catalyst.

  8. Evaluation of the leaching characteristics of wood ash and the influence of ash agglomeration

    Energy Technology Data Exchange (ETDEWEB)

    Steenari, B.-M.; Lindqvist, O. [Chalmers University of Technology, Goeteborg (Sweden); Karlsson, L.G. [Kemakta Consulting AB, Stockholm (Sweden)

    1999-11-01

    The release of mineral nutrients and other species from untreated and stabilised wood ash has been investigated. Stabilisation is applied with the aim to modify the solubility of ash components and the ash particle size, i.e. to form dense ash particle agglomerates. This process induces the formation of several secondary minerals. The most important reaction is the transformation of Ca(OH){sub 2} into CaCO{sub 3} which lowers the calcium leaching rate significantly. A significant fraction of the alkali metals, K and Na, is present in salts which are rapidly released. The short-term release of these salts, as simulated in laboratory experiments, was not reduced by the stabilisation methods applied. Generally, low leaching rates were observed for the important plant nutrients P and Mg as well as for Fe and other metals from both untreated and agglomerated ashes. Thermodynamics equilibrium modelling of the hardening process showed that in addition to the transformation of Ca(OH){sub 2} to CaCO{sub 3}, formation of the mineral ettringite is possible at a high pH. Experimental results have confirmed this. As the pH in the pore solution decreases during long-term leaching ettringite will be transformed into calcium carbonate and gypsum. In accordance with the experimental results, no formation of secondary solubility controlling potassium or sodium minerals was indicated by the modelling results. (author)

  9. Calcium Oxalate Stone Agglomeration Inhibition [tm] Reflects Renal Stone-Forming Activity.

    Science.gov (United States)

    Lindberg, J S; Cole, F E; Romani, W; Husserl, F E; Fuselier, H A; Kok, D J; Erwin, D T

    2000-04-01

    Louisiana and other Gulf South states comprise a "Stone Belt" where calcium oxalate stone formers (CaOx SFs) are found at a high rate of approximately 5%. In these patients, the agglomeration of small stone crystals, which are visible in nearly all morning urine collections, forms stones that can become trapped in the renal parenchyma and the renal pelvis. Without therapy, about half of CaOx SFs repeatedly form kidney stones, which can cause excruciating pain that can be relieved by passage, fragmentation (lithotripsy), or surgical removal. The absence of stones in "normal" patients suggests that there are stone inhibitors in "normal" urines.At the Ochsner Renal Stone Clinic, 24-hour urine samples are collected by the patient and sent to the Ochsner Renal Stone Research Program where calcium oxalate stone agglomeration inhibition [tm] measurements are performed. Urine from healthy subjects and inactive stone formers has demonstrated strongly inhibited stone growth [tm] in contrast to urine from recurrent CaOx SFs. [tm] data from 1500 visits of 700 kidney stone patients have been used to evaluate the risk of recurrence in Ochsner's CaOx SF patients. These data have also been used to demonstrate the interactive roles of certain identified urinary stone-growth inhibitors, citrate and Tamm-Horsfall protein (THP), which can be manipulated with medication to diminish recurrent stone formation. Our goal is to offer patients both financial and pain relief by reducing their stones with optimized medication, using medical management to avoid costly treatments.

  10. 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.

  11. 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.

  12. 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.

  13. The role of nanoparticulate agglomerates in TiO2 photocatalysis: degradation of oxalic acid

    Science.gov (United States)

    Ivanova, Irina; Mendive, Cecilia B.; Bahnemann, Detlef

    2016-07-01

    The simultaneous bimodal study of the photocatalytic oxalic acid degradation by aqueous TiO2 suspensions revealed that particular systems possess the capacity to protect a certain amount of oxalic acid from oxidation, thus hindering, to some extent, the photocatalytic reaction. While measurements of the oxalic acid concentration in the bulk liquid phase indicated full photocatalytic degradation; in situ pH-stat measurements allowed the quantification of the amount of oxalic acid remaining in the part of the nanoparticulate agglomerates where light could apparently not access. An explanation for this phenomenon takes into account the possibility of the formation of TiO2 agglomerates in which these molecules are hidden from the effect of the light, thus being protected from photocatalytic degradation. Studies of different TiO2 materials with different particle sizes allowed a deeper exploration of this phenomenon. In addition, because this property of encapsulating pollutant molecules by photocatalytic systems is found to be a reversible phenomenon, P25 appears to be more convenient and advantageous as compared to the use of large surface area photocatalysts.

  14. Experimental and theoretical studies of agglomeration effects in multi-walled carbon nanotube-polycarbonate melts

    Directory of Open Access Journals (Sweden)

    2009-12-01

    Full Text Available In this study we report on morphological and rheological characterization of multi-walled carbon nanotube (MWNT-polycarbonate composites produced by injection molding. The main focus is to carry out nonlinear viscoelastic experiments that allow following the structural rearrangements of carbon nanotubes in the polycarbonate melt. Small angle X-ray scattering reveals only a slight orientation of MWNTs in the as-received samples, i.e. after application of extremely high shear rates. Thus, the main structural effect observed during the stress growth experiment is the breakage of MWNT agglomerates. To study this effect in detail a flocculation experiment, in which the sample undergoes oscillatory deformation first at a small strain amplitude in the linear regime succeeded by higher amplitudes in the nonlinear regime, has been carried out. The agglomeration process manifests itself in an increase of the storage and loss moduli in the linear regime, whereas the deagglomeration process does vice versa. The corresponding effects can be described in the frame of a superposition approach that takes into account the stress contribution of the polycarbonate matrix, the hydrodynamic reinforcement due to embedded nanotubes and the viscoelastic stress due to the presence of a MWNT-network.

  15. An accelerated stochastic vortex structure method for particle collision and agglomeration in homogeneous turbulence

    Science.gov (United States)

    Dizaji, Farzad F.; Marshall, Jeffrey S.

    2016-11-01

    Modeling the response of interacting particles, droplets, or bubbles to subgrid-scale fluctuations in turbulent flows is a long-standing challenge in multiphase flow simulations using the Reynolds-Averaged Navier-Stokes approach. The problem also arises for large-eddy simulation for sufficiently small values of the Kolmogorov-scale particle Stokes number. This paper expands on a recently proposed stochastic vortex structure (SVS) method for modeling of turbulence fluctuations for colliding or otherwise interacting particles. An accelerated version of the SVS method was developed using the fast multipole expansion and local Taylor expansion approach, which reduces computation speed by two orders of magnitude compared to the original SVS method. Detailed comparisons are presented showing close agreement of the energy spectrum and probability density functions of various fields between the SVS computational model, direct numerical simulation (DNS) results, and various theoretical and experimental results found in the literature. Results of the SVS method for particle collision rate and related measures of particle interaction exhibit excellent agreement with DNS predictions for homogeneous turbulent flows. The SVS method was also used with adhesive particles to simulate formation of particle agglomerates with different values of the particle Stokes and adhesion numbers, and various measures of the agglomerate structure are compared to the DNS results.

  16. 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.

  17. 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.

  18. Development of a fluidized bed agglomeration modeling methodology to include particle-level heterogeneities in ash chemistry and granular physics

    Science.gov (United States)

    Khadilkar, Aditi B.

    The utility of fluidized bed reactors for combustion and gasification can be enhanced if operational issues such as agglomeration are mitigated. The monetary and efficiency losses could be avoided through a mechanistic understanding of the agglomeration process and prediction of operational conditions that promote agglomeration. Pilot-scale experimentation prior to operation for each specific condition can be cumbersome and expensive. So the development of a mathematical model would aid predictions. With this motivation, the study comprised of the following model development stages- 1) development of an agglomeration modeling methodology based on binary particle collisions, 2) study of heterogeneities in ash chemical composition and gaseous atmosphere, 3) computation of a distribution of particle collision frequencies based on granular physics for a poly-disperse particle size distribution, 4) combining the ash chemistry and granular physics inputs to obtain agglomerate growth probabilities and 5) validation of the modeling methodology. The modeling methodology comprised of testing every binary particle collision in the system for sticking, based on the extent of dissipation of the particles' kinetic energy through viscous dissipation by slag-liquid (molten ash) covering the particles. In the modeling methodology developed in this study, thermodynamic equilibrium calculations are used to estimate the amount of slag-liquid in the system, and the changes in particle collision frequencies are accounted for by continuously tracking the number density of the various particle sizes. In this study, the heterogeneities in chemical composition of fuel ash were studied by separating the bulk fuel into particle classes that are rich in specific minerals. FactSage simulations were performed on two bituminous coals and an anthracite to understand the effect of particle-level heterogeneities on agglomeration. The mineral matter behavior of these constituent classes was studied

  19. Impact of Climate Change on Urban Agglomerations in China's Coastal Region

    Institute of Scientific and Technical Information of China (English)

    Dong Suocheng; Tao Shu; YangWangzhou; Li Fei; LiShuangcheng; Li Yu; Liu Hongyan

    2012-01-01

    Climate change and urbanization issues are the two key factors that make humans liable to be affected by disasters, which are overlapped in urban agglomeration. The five big urban agglom- erations of China with strong economic power are the important engines for national economic and social development. However, being in the sea-land mutual interaction belts with a vast hazard- bearing body, they are affected by sea-land compound disasters, and are liable to suffer heavy disaster losses with climate change. It is suggested that government departments concerned should fully recognize the impact of climate change on coastal urban ag- glomerations, propose strategies as soon as possible, and integrate the impact of climate change and adaptation countermeasures into the various kinds of social-economic development plans for coastal urban regions.

  20. 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.

  1. 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.

  2. 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.

  3. Agglomeration, isolation and dissolution of commercially manufactured silver nanoparticles in aqueous environments

    Science.gov (United States)

    Elzey, Sherrie; Grassian, Vicki H.

    2010-06-01

    The increasing use of manufactured nanoparticles ensures these materials will make their way into the environment. Silver nanoparticles in particular, due to use in a wide range of applications, have the potential to get into water systems, e.g., drinking water systems, ground water systems, estuaries, and/or lakes. One important question is what is the chemical and physical state of these nanoparticles in water? Are they present as isolated particles, agglomerates or dissolved ions, as this will dictate their fate and transport. Furthermore, does the chemical and physical state of the nanoparticles change as a function of size or differ from micron-sized particles of similar composition? In this study, an electrospray atomizer coupled to a scanning mobility particle sizer (ES-SMPS) is used to investigate the state of silver nanoparticles in water and aqueous nitric acid environments. Over the range of pH values investigated, 0.5-6.5, silver nanoparticles with a bimodal primary particle size distribution with the most intense peak at 5.0 ± 7.4 nm, as determined from transmission electron microscopy (TEM), show distinct size distributions indicating agglomeration between pH 6.5 and 3 and isolated nanoparticles at pH values from 2.5 to 1. At the lowest pH investigated, pH 0.5, there are no peaks detected by the SMPS, indicating complete nanoparticle dissolution. Further analysis of the solution shows dissolved Ag ions at a pH of 0.5. Interestingly, silver nanoparticle dissolution shows size dependent behavior as larger, micron-sized silver particles show no dissolution at this pH. Environmental implications of these results are discussed.

  4. The Physics of Protoplanetesimal Dust Agglomerates. Vi. Erosion of Large Aggregates and its Consequences for the Dust-Size Distribution

    CERN Document Server

    Schräpler, Rainer

    2011-01-01

    Observed protoplanetary disks consist of a large amount of micrometer-sized particles. Dullemond and Dominik (2005) pointed out for the first time the difficulty in explaining the strong mid-IR excess of classical T-Tauri stars without any dust-retention mechanisms. Because high relative velocities in between micrometer-sized and macroscopic particles exist in protoplanetary disks, we present experimental results on the erosion of macroscopic agglomerates consisting of micrometer-sized spherical particles via the impact of micrometer-sized particles. We find that after an initial phase, in which an impacting particle erodes up to 10 particles of an agglomerate, the impacting particles compress the agglomerate's surface, which partly passivates the agglomerates against erosion. Due to this effect the erosion halts within our error bars for impact velocities up to ~30 m/s. For larger velocities, the erosion is reduced by an order of magnitude. This outcome is explained and confirmed by a numerical model. In a n...

  5. 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

  6. Steric stabilization of nonaqueous silicon slips. I - Control of particle agglomeration and packing. II - Pressure casting of powder compacts

    Science.gov (United States)

    Kerkar, Awdhoot V.; Henderson, Robert J. M.; Feke, Donald L.

    1990-01-01

    The application of steric stabilization to control particle agglomeration and packing of silicon powder in benzene and trichloroethylene is reported. The results provide useful guidelines for controlling unfavorable particle-particle interactions during nonaqueous processing of silicon-based ceramic materials. The application of steric stabilization to the control and improvement of green processing of nonaqueous silicon slips in pressure consolidation is also demonstrated.

  7. 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

  8. The influence of particle size, fluidization velocity and fuel type on ash-induced agglomeration in biomass combustion

    Directory of Open Access Journals (Sweden)

    Bernhard eGatternig

    2014-11-01

    Full Text Available Agglomeration of the bed material is one of the main obstacles for biomass utilization in fluidized bed combustors. Especially high-potential fuels such as fast growing energy crops or biogeneous residues are affected, due to their high content of alkaline metals. Despite ongoing research efforts, the knowledge base on what fuels are affected is still limited. This paper describes the design and installation of two lab-scale reactors for the experimental determination of agglomeration temperatures. The reactor concept and measurement method were developed under consideration of experiences from existing test rigs published in literature. Preliminary tests confirmed a reproducibility of ±5°C for both new reactors.The results of an extended measurement campaign (156 test runs of 25 fuel species at a wide range of the operational parameters bed particle size, gas velocity, bed ash accumulation, based on design of experiment criteria, showed high agglomeration tendencies for residues (e.g., dried distillery grains, corn cobs while woody energy crops (e.g., willow, alder exhibited very stable combustion behavior. The operating parameters influenced the agglomeration behavior to a lesser degree than different ash compositions of fuel species tested. An interpolation within the design of experiment factor space allowed for a subsequent comparison of our results with experiments reported in literature. Good agreement was reached for fuels of comparable ash composition considering the interpolation errors of ±32°C on average.

  9. 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

  10. 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

  11. The definition and identification of urban agglomerations%城市群的界定与识别研究

    Institute of Scientific and Technical Information of China (English)

    王丽; 邓羽; 牛文元

    2013-01-01

    The definition and identification are important contents in the urban agglomeration research.Traditional studies rely on empirical data,and the implementation is limited due to the difficulty of gathering data.However,modeling study is rare,and the finite precision is the main disadvantage.Based on the previous studies,this paper develops the definition of urban agglomeration; by combining models and methods,(and) identification system of urban agglomeration is proposed.By qualitative and quantitative analyses,urban agglomeration is delineated more efficiently and precisely.This research will help to both define urban agglomerations and identify them in practice.%城市群的界定与识别是城市群研究的重要内容之一.传统研究以实证数据判断为主,但由于数据可获取性不易,极大的限制了该手段的应用;模型等定量识别方法较少采用,结果的精度较差是其主要弊端.本文在综合以往学者研究的基础上,提出城市群界定的标准体系;运用区域作用组合模型,得出城市群的识别体系.通过模型与实证相结合,更加高效和精确地识别城市群.通过研究,为城市群的界定提供一种研究思路,并为城市群识别的操作层面提供了一种测度手段.

  12. Computational imaging analysis of fibrin matrices with the inclusion of erythrocytes from homozygous SS blood reveals agglomerated and amorphous structures.

    Science.gov (United States)

    Averett, Rodney D; Norton, David G; Fan, Natalie K; Platt, Manu O

    2017-01-01

    Sickle cell disease is a single point mutation disease that is known to alter the coagulation system, leading to hypercoagulable plasma conditions. These hypercoagulable conditions can lead to complications in the vasculature, caused by fibrin clots that form undesirably. There is a need to understand the morphology and structure of fibrin clots from patients with sickle cell disease, as this could lead to further discovery of treatments and life-saving therapies. In this work, a computational imaging analysis method is presented to evaluate fibrin agglomeration in the presence of erythrocytes (RBCs) homozygous for the sickle cell mutation (SS). Numerical algorithms were used to determine agglomeration of fibrin fibers within a matrix with SS RBCs to test the hypothesis that fibrin matrices with the inclusion of SS RBCs possess a more agglomerated structure than native fibrin matrices with AA RBCs. The numerical results showed that fibrin structures with SS RBCs displayed an overall higher degree of agglomeration as compared to native fibrin structures. The computational algorithm was also used to evaluate fibrin fiber overlap (aggregation) and anisotropy (orientation) in normal fibrin matrices compared to fibrin matrices polymerized around SS RBCs; however, there was no statistical difference. Ultrasound measurements of stiffness revealed rigid RBCs in the case of samples derived from homozygous SS blood, and densely evolving matrices, when compared to normal fibrin with the inclusion of AA RBCs. An agglomeration model is suggested to quantify the fibrin aggregation/clustering near RBCs for both normal fibrin matrices and for the altered structures. The results of this work are important in the sense that the understanding of aggregation and morphology in fibrin clots with incorporation of RBCs from persons living with sickle cell anemia may elucidate the complexities of comorbidities and other disease complications.

  13. A variational approach to environmental and climatic problems of urban agglomerations

    Science.gov (United States)

    Penenko, V. V.; Tsvetova, E. A.

    2016-11-01

    We discuss some aspects of the development of a variational approach to study the dynamics of climatic and ecological systems under intensive actions of natural and anthropogenic origin. The variational principle essentially represents a versatile tool to create a consistent modeling technology based on models of processes coupled with available observational data. The basic entities included in the formulation of the variational principle are models of processes; data and models of observations; target criteria for forecasting; a priori information about all the required elements of the system. We develop a set of mathematical models combined within the framework of the variational principle. They describe the dynamics of the atmosphere and water bodies in conjunction with a thermally and dynamically heterogeneous surface of the Earth; the hydrological cycle, moisture in the atmosphere and the soil; radiation transfer in the system of the atmosphere and the underlying surface; and transport and transformation of various substances in gaseous and aerosol states in the atmosphere. As an example, we demonstrate the results of calculations performed with a set of numerical models adapted to the conditions of a Novosibirsk city agglomeration. The results of scenario calculations on the formation of mesoclimates and quality of the atmosphere for the typical conditions of Siberian cities are presented.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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...

  19. Assessment of ecological status in small urban streams of Prague agglomeration.

    Science.gov (United States)

    Nábelková, J; Komínková, D; St'astná, G

    2004-01-01

    The purpose of this research was to compare ecological status of a few small urban watersheds in Prague agglomeration (the Botic creek, the Zátisský creek and the Komoranský creek) with different sources of pollution, different sewer systems and with different hydraulic regimes of the recipient. Concentrations of selected heavy metals (Cd, Cu, Ni, Pb, Zn) were measured in water and sediment samples and in different species of benthic organisms. The biological assessment of macrozoobenthos has also been carried out using two biotic indexes: the saprobic index and the ASPT. The assessment of the environmental risk in an aquatic environment has been based on three different coefficients: the Distribution coefficient (Kd), the Hazard Quotient (HQ) and the Metal Pollution Index (MPI). In the Botic creek there was found out chronic load of bottom sediment by heavy metals. There is higher ecological risk of sediment toxicity in this creek. Outlets of combined sewer system in the Botic creek degrade water quality and consequently deteriorate biological indicators. In the Zátisský creek the main problem is connected with storm sewer outlets. The comparison of the Zátisský creek with the reference stream, the Komoranský creek demonstrates strong hydraulic impact, which induces frequent changes of watercourse morphology reflecting on the composition and representation of benthic macroorganisms.

  20. 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.

  1. 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.

  2. HVOF and HVAF Coatings of Agglomerated Tungsten Carbide-Cobalt Powders for Water Droplet Erosion Application

    Science.gov (United States)

    Tarasi, F.; Mahdipoor, M. S.; Dolatabadi, A.; Medraj, M.; Moreau, C.

    2016-12-01

    Water droplet erosion (WDE) is a phenomenon caused by impingement of water droplets of several hundred microns to a few millimeters diameter at velocities of hundreds of meters per second on the edges and surfaces of the parts used in such services. The solution to this problem is sought especially for the moving compressor blades in gas turbines and those operating at the low-pressure end of steam turbines. Thermal-sprayed tungsten carbide-based coatings have been the focus of many studies and are industrially accepted for a multitude of wear and erosion resistance applications. In the present work, the microstructure, phase analysis and mechanical properties (micro-hardness and fracture toughness) of WC-Co coatings are studied in relation with their influence on the WDE resistance of such coatings. The coatings are deposited by high-velocity oxygen fuel (HVOF) and high-velocity air fuel (HVAF) processes. The agglomerated tungsten carbide-cobalt powders were in either sintered or non-sintered conditions. The WDE tests were performed using 0.4 mm water droplets at 300 m/s impact velocity. The study shows promising results for this cermet as WDE-resistant coating when the coating can reach its optimum quality using the right thermal spray process and parameters.

  3. 城市群研究述评与展望%Review and Prospect on Urban Agglomeration

    Institute of Scientific and Technical Information of China (English)

    李仙德; 宁越敏

    2012-01-01

    After Gottmann introduced the concept of Megalopolis in 1957,the urban agglomeration,as a special form of the urban system,has been the core content of urban geography.Since the reform and opening up,China's urban spatial organization has presented a new trend.Urban agglomerations are emerging as engines of Chinese economy.The State Council of China has also issued a series of important plans to take the urban agglomerations as national and regional growth poles and main form of urbanization.This article reviews the most important domestic and foreign literature on important concepts including 'Megalopolis','Desakota Region','Global City-Region','Polycentric Mega City-Region','Metropolitan Interlocking Region' and 'Urban Agglomeration'.Gottmann argued that megalopolis was the hub and incubator of national development.He pointed out there were six megalopolises around the world.Mcgee,based on the actual development of Asia,put forward different spatial pattern namely dasakota.Scott et al.paid attention to the effect of globalization and localization on city and regional development.They argued that global city-regions were the most important actors of the world.Hall et al.integrated research method of economic geography and urban geography to study the polycentric mega city-region.This study was innovative and enlightening.Zhou Yixing argued that the research on metropolitan interlocking region must be based on definition of metropolitan area.Yao Shimou introduced the concept of urban agglomeration systematicly.It is also the most popular spatial concept in China.Chinese scholars have done a lot of work on urban agglomerations,while the concept of urban agglomeration is not clearly defined.Because of confusion on definition,spatial scale of urban agglomeration is uncertain.So it is hard to establish the research paradigm of urban agglomeration in China.Regional and national planning on urban agglomeration is also impacted by this fuzzy

  4. Fluidized-Bed Coating with Sodium Sulfate and PVA-TiO2, 1. Review and Agglomeration Regime Maps

    DEFF Research Database (Denmark)

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

    2009-01-01

    This paper, and two associated papers [Hede, P. D.; Jensen, A. D.; Bach, P. Ind. Eng. Chem. Res. 2009, 48, 1905 and 1914], address the fluid-bed coating of placebo enzyme granules (i.e., sodium sulfate cores, with a size range of 400-500 mu m) using two types of coatings: sodium sulfate and PVA......-TiO2. The coating experiments were conducted in a medium-scale top-spray MP-1 fluid bed, and many rheological experiments were performed on the coating formulations to support the interpretation of the fluid-bed coating results. In this first part of the study, a thorough introduction to the inorganic...... salt and polymer film coating is provided, along with a presentation of the equipment and materials being used in this and the following papers. Results from agglomeration studies over a broad range of process conditions are presented, showing that the tendency toward agglomeration is always less...

  5. How much drinking water can be saved by using rainwater harvesting on a large urban area? application to Paris agglomeration.

    Science.gov (United States)

    Belmeziti, Ali; Coutard, Olivier; de Gouvello, Bernard

    2014-01-01

    This paper is based on a prospective scenario of development of rainwater harvesting (RWH) on a given large urban area (such as metropolitan area or region). In such a perspective, a new method is proposed to quantify the related potential of potable water savings (PPWS) indicator on this type of area by adapting the reference model usually used on the building level. The method is based on four setting-up principles: gathering (definition of buildings-types and municipalities-types), progressing (use of an intermediate level), increasing (choice of an upper estimation) and prioritizing (ranking the stakes of RWH). Its application to the Paris agglomeration shows that is possible to save up to 11% of the total current potable water through the use of RWH. It also shows that the residential sector offers the most important part because it holds two-thirds of the agglomeration PPWS.

  6. 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.

  7. Pulmonary toxicity and fate of agglomerated 10 and 40 nm aluminum oxyhydroxides following 4-week inhalation exposure of rats: toxic effects are determined by agglomerated, not primary particle size.

    Science.gov (United States)

    Pauluhn, Jürgen

    2009-05-01

    Inhaled polydisperse micronsized agglomerated particulates composed of nanosized primary particles may exert their pulmonary toxicity in either form, depending on whether these tightly associated structures are disintegrated within the biological system or not. This hypothesis was tested in a rat bioassay using two calcined aluminum oxyhydroxides (AlOOH) consisting of primary particles in the range of 10-40 nm. Male Wistar rats were nose-only exposed to 0.4, 3, and 28 mg/m(3) in two 4-week (6 h/day, 5 days/week) inhalation studies followed by a 3-month postexposure period. The respective mass median aerodynamic diameter (MMAD) of agglomerated particles in inhalation chambers was 1.7 and 0.6 mum. At serial sacrifices, pulmonary toxicity was characterized by bronchoalveolar lavage (BAL) and histopathology. The retention kinetics of aluminum (Al) was determined in lung tissue, BAL cells, and selected extrapulmonary organs, including lung-associated lymph nodes (LALNs). Significant changes in BAL, lung, and LALN weights occurred at 28 mg/m(3). Histopathology revealed alveolar macrophages with enlarged and foamy appearance, increased epithelial cells, inflammatory cells, and focal septal thickening. The determination of aluminum in lung tissue shows that the cumulative lung dose was higher following exposure to AlOOH-40 nm/MMAD-0.6 mum than to AlOOH-10 nm/MMAD-1.7 mum, despite identical exposure concentrations. The associated pulmonary inflammatory response appears to be principally dependent on the agglomerated rather than primary particle size. Despite high lung burdens, conclusively increased extrapulmonary organ burdens did not occur at any exposure concentration and postexposure time point. Particle-induced pulmonary inflammation was restricted to cumulative doses exceeding approximately 1 mg AlOOH/g lung following 4-week exposure at 28 mg/m(3). It is concluded that the pulmonary toxicity of nanosized, agglomerated AlOOH particles appears to be determined by the

  8. Mode-switching: a new technique for electronically varying the agglomeration position in an acoustic particle manipulator.

    Science.gov (United States)

    Glynne-Jones, Peter; Boltryk, Rosemary J; Harris, Nicholas R; Cranny, Andy W J; Hill, Martyn

    2010-01-01

    Acoustic radiation forces offer a means of manipulating particles within a fluid. Much interest in recent years has focussed on the use of radiation forces in microfluidic (or "lab on a chip") devices. Such devices are well matched to the use of ultrasonic standing waves in which the resonant dimensions of the chamber are smaller than the ultrasonic wavelength in use. However, such devices have typically been limited to moving particles to one or two predetermined planes, whose positions are determined by acoustic pressure nodes/anti-nodes set up in the ultrasonic standing wave. In most cases devices have been designed to move particles to either the centre or (more recently) the side of a flow channel using ultrasonic frequencies that produce a half or quarter wavelength over the channel, respectively. It is demonstrated here that by rapidly switching back and forth between half and quarter wavelength frequencies - mode-switching - a new agglomeration position is established that permits beads to be brought to any arbitrary point between the half and quarter-wave nodes. This new agglomeration position is effectively a position of stable equilibrium. This has many potential applications, particularly in cell sorting and manipulation. It should also enable precise control of agglomeration position to be maintained regardless of manufacturing tolerances, temperature variations, fluid medium characteristics and particle concentration.

  9. 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

  10. Integrated low emission cleanup system for direct coal-fueled turbines (electrostatic agglomeration). Draft final technical report

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-12-31

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

  11. AC impedance modelling study on porous electrodes of proton exchange membrane fuel cells using an agglomerate model

    Science.gov (United States)

    Gerteisen, Dietmar; Hakenjos, Alex; Schumacher, Jürgen O.

    A one-dimensional model of the PEM fuel cell cathode is developed to analyse ac impedance spectra and polarisation curves. The porous gas diffusion electrode is assumed to consist of a network of dispersed catalyst (Pt/C) forming spherically shaped agglomerated zones that are filled with electrolyte. The coupled differential equation system describes: ternary gas diffusion in the backing (O2 , N2 , water vapour), Fickian diffusion and Tafel kinetics for the oxygen reduction reaction (ORR) inside the agglomerates, proton migration with ohmic losses and double-layer charging in the electrode. Measurements are made of a temperature-controlled fuel cell with a geometric area of 1.4 cm × 1.4 cm. Lateral homogeneity is ensured by using a high stoichiometry of λmin . The model predicts the behaviour of measured polarisation curves and impedance spectra. It is found that a better humidification of the electrode leads to a higher volumetric double-layer capacity. The catalyst layer resistance shows the same behaviour depending on the humidification as the membrane resistance. Model parameters, e.g. Tafel slope, ionic resistance and agglomerate radius are varied. A sensitivity analysis of the model parameters is conducted.

  12. Temperature-dependent breakdown of hydrogen peroxide-treated ZnO and TiO2 nanoparticle agglomerates

    Directory of Open Access Journals (Sweden)

    Sinan Sabuncu

    2015-09-01

    Full Text Available Metal oxide nanoparticles (MONPs are used in a variety of applications including drug formulations, paint, sensors and biomedical devices due to their unique physicochemical properties. One of the major problems with their widespread implementation is their uncontrolled agglomeration. One approach to reduce agglomeration is to alter their surface chemistry with a proper functionality in an environmentally friendly way. In this study, the influence of hydrogen peroxide (H2O2 treatment on the dispersion of ZnO and TiO2 nanoparticle (NP agglomerates as a function of temperature is studied. The H2O2 treatment of the MONPs increases the density of hydroxyl (–OH groups on the NP surface, as verified with FTIR spectroscopy. The influence of heating on the dispersion of H2O2-treated ZnO and TiO2 NPs is investigated using dynamic light scattering. The untreated and H2O2-treated ZnO and TiO2 NP suspensions were heated from 30 °C to 90 °C at 5 °C intervals to monitor the breakdown of large aggregates into smaller aggregates and individual nanoparticles. It was shown that the combined effect of hydroxylation and heating enhances the dispersion of ZnO and TiO2 NPs in water.

  13. Development of Impregnated Agglomerate Pelletization (IAP) process for fabrication of (Th,U)O 2 mixed oxide pellets

    Science.gov (United States)

    Khot, P. M.; Nehete, Y. G.; Fulzele, A. K.; Baghra, Chetan; Mishra, A. K.; Afzal, Mohd.; Panakkal, J. P.; Kamath, H. S.

    2012-01-01

    Impregnated Agglomerate Pelletization (IAP) technique has been developed at Advanced Fuel Fabrication Facility (AFFF), BARC, Tarapur, for manufacturing (Th, 233U)O 2 mixed oxide fuel pellets, which are remotely fabricated in hot cell or shielded glove box facilities to reduce man-rem problem associated with 232U daughter radionuclides. This technique is being investigated to fabricate the fuel for Indian Advanced Heavy Water Reactor (AHWR). In the IAP process, ThO 2 is converted to free flowing spheroids by powder extrusion route in an unshielded facility which are then coated with uranyl nitrate solution in a shielded facility. The dried coated agglomerate is finally compacted and then sintered in oxidizing/reducing atmosphere to obtain high density (Th,U)O 2 pellets. In this study, fabrication of (Th,U)O 2 mixed oxide pellets containing 3-5 wt.% UO 2 was carried out by IAP process. The pellets obtained were characterized using optical microscopy, XRD and alpha autoradiography. The results obtained were compared with the results for the pellets fabricated by other routes such as Coated Agglomerate Pelletization (CAP) and Powder Oxide Pelletization (POP) route.

  14. Impact of alginate concentration on the stability of agglomerates made of TiO{sub 2} engineered nanoparticles: Water hardness and pH effects

    Energy Technology Data Exchange (ETDEWEB)

    Loosli, Frédéric, E-mail: frederic.loosli@unige.ch [University of Geneva, Section des Sciences de la Terre et de l’Environnement, Group of Environmental Physical Chemistry, F.-A. Forel Institute (Switzerland); Coustumer, Philippe Le, E-mail: philippe.le-coustumer@u-bordeaux1.fr [Université Bordeaux 3, EA 4592 Géoressources & Environnement, ENSEGID (France); Stoll, Serge, E-mail: serge.stoll@unige.ch [University of Geneva, Section des Sciences de la Terre et de l’Environnement, Group of Environmental Physical Chemistry, F.-A. Forel Institute (Switzerland)

    2015-01-15

    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 (Mg{sup 2+} and Ca{sup 2+}) in agglomerate formation and (ii) alginate concentration effect on the stability TiO{sub 2} 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 TiO{sub 2} nanoparticle agglomerates by inducing their partial disagglomeration. Significant TiO{sub 2} 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.

  15. The Paris MEGAPOLI campaign to better quantify organic aerosol formation in a large agglomeration: first results

    Science.gov (United States)

    Beekmann, Matthias; Baltensperger, Urs; Sciare, Jean; Gros, Valérie; Borbon, Agnes; Baklanov, Alexander; Lawrence, Mark; Pandis, Spyros

    2010-05-01

    Within the FP7 MEGAPOLI project, two intensive field campaigns have been conducted in the Greater Paris region during July 2009 and January/February 2010. The major aim was to quantify sources of primary and secondary aerosol, and the interaction with gaseous precursors, within a large agglomeration, and in its plume. Greater Paris has been chosen for such a campaign because it is a major and dense pollution source (more than 10 million inhabitants), surrounded by rural areas and relatively flat terrain. A particular focus is put on organic carbon, for which secondary formation, but also primary emissions are still not well quantified. Detailed aerosol and gaseous precursor measurements have been conducted at an urban and two sub-urban sites, from five mobile platforms and from the French ATR-42 research aircraft (for plume characterisation). State of the art instrumentation has allowed determination of aerosol chemical composition, either with very high frequency (several minutes to half an hour), or with large chemical detail (several dozens of organic compounds from filter samples). In addition, the size distribution, optical and hygroscopic and mixing properties has been determined in order to relate the aerosol chemical composition to its potential radiative and climate impact in the urban region and its plume. Gas phase measurements have focussed especially on detailed VOC measurements in order to relate SOA build-up to gaseous precursor species abundance. A network of backscatter lidars at urban and rural sites and on a mobile platform gives the access to the aerosol vertical distribution in the region and to variations of the boundary layer height at the urban / rural interface. Meteorological parameters and especially wind profile measurements allow interpretation of transport processes in the region. In this paper, the campaign set-up and objectives, meteorological and general pollution conditions observed during the field experiments and a first overview

  16. Formulation of SrO-MBCUS Agglomerates for Esterification and Transesterification of High FFA Vegetable Oil

    Directory of Open Access Journals (Sweden)

    Prashant Kumar

    2016-08-01

    Full Text Available Musa Balbisiana Colla Underground Stem (MBCUS catalyst was treated thermally mixing with 5:1 w/w of Strontium Oxide (SrO and the dynamic sites were reformed. The MBCUS-SrO showed sharper crystalline phases as evidence from XRD and TEM analysis. The composition and morphology were characterized from BET, SEM, EDX thermo-gravimetric analysis (TGA and XRF analysis. The optimization process for biodiesel production from Jatropha curcas L oil (JCO having high percentage of free fatty acids was carried out using orthogonal arrays adopting the Taguchi method. The linear equation was obtained from the analysis and subsequent biodiesel production (96% FAME was taken away from the JCO under optimal reaction conditions. The biodiesel so prepared had identical characteristics to that with MBCUS alone, but at a lower temperature (200˚C and internal vapour pressure. Metal leaching was much lower while reusability of the catalyst was enhanced. It was also confirmed that the particle size has little impact upon the conversion efficacy, but the basic active sites are more important. Copyright © 2016 BCREC GROUP. All rights reserved Received: 19th August 2015; Revised: 8th December 2015; Accepted: 1st January 2016 How to Cite: Kumar, P., Sarma, A.K., Bansal, A., Jha, M.K. (2016. Formulation of SrO-MBCUS Agglomerates for Esterification and Transesterification of High FFA Vegetable Oil. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (2: 140-150 (doi:10.9767/bcrec.11.2.540.140-150 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.2.540.140-150

  17. A PROTOSOLAR NEBULA ORIGIN FOR THE ICES AGGLOMERATED BY COMET 67P/CHURYUMOV–GERASIMENKO

    Energy Technology Data Exchange (ETDEWEB)

    Mousis, O.; Vernazza, P. [Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France); Lunine, J. I. [Center For Radiophysics And Space Research, Space Sciences Building Cornell University, Ithaca, NY 14853 (United States); Luspay-Kuti, A.; Hässig, M.; Waite, J. H. [Department of Space Research, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78228 (United States); Guillot, T. [Laboratoire J.-L. Lagrange, Université de Nice-Sophia Antipolis, CNRS, Observatoire de la Côte d’Azur, BP 4229, F-06304 Nice (France); Marty, B. [CRPG-CNRS, Nancy-Université, 15 rue Notre Dame des Pauvres, F-54501 Vandoeuvre-lès-Nancy (France); Ali-Dib, M. [Université de Franche-Comté, Institut UTINAM, CNRS/INSU, UMR 6213, Besançon Cedex (France); Wurz, P.; Altwegg, K.; Bieler, A.; Rubin, M., E-mail: olivier.mousis@lam.fr [Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern (Switzerland)

    2016-03-10

    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 N{sub 2}/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 N{sub 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 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 N{sub 2}, 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.

  18. 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.

  19. Computational prediction of the refinement of oxide agglomerates in a physical conditioning process for molten aluminium alloy

    Science.gov (United States)

    Tong, M.; Jagarlapudi, S. C.; Patel, J. B.; Stone, I. C.; Fan, Z.; Browne, D. J.

    2015-06-01

    Physically conditioning molten scrap aluminium alloys using high shear processing (HSP) was recently found to be a promising technology for purification of contaminated alloys. HSP refines the solid oxide agglomerates in molten alloys, so that they can act as sites for the nucleation of Fe-rich intermetallic phases which can subsequently be removed by the downstream de-drossing process. In this paper, a computational modelling for predicting the evolution of size of oxide clusters during HSP is presented. We used CFD to predict the macroscopic flow features of the melt, and the resultant field predictions of temperature and melt shear rate were transferred to a population balance model (PBM) as its key inputs. The PBM is a macroscopic model that formulates the microscopic agglomeration and breakage of a population of a dispersed phase. Although it has been widely used to study conventional deoxidation of liquid metal, this is the first time that PBM has been used to simulate the melt conditioning process within a rotor/stator HSP device. We employed a method which discretizes the continuous profile of size of the dispersed phase into a collection of discrete bins of size, to solve the governing population balance equation for the size of agglomerates. A finite volume method was used to solve the continuity equation, the energy equation and the momentum equation. The overall computation was implemented mainly using the FLUENT module of ANSYS. The simulations showed that there is a relatively high melt shear rate between the stator and sweeping tips of the rotor blades. This high shear rate leads directly to significant fragmentation of the initially large oxide aggregates. Because the process of agglomeration is significantly slower than the breakage processes at the beginning of HSP, the mean size of oxide clusters decreases very rapidly. As the process of agglomeration gradually balances the process of breakage, the mean size of oxide clusters converges to a

  20. Determination of Uniaxial Compressive Strength of Ankara Agglomerate Considering Fractal Geometry of Blocks

    Science.gov (United States)

    Coskun, Aycan; Sonmez, Harun; Ercin Kasapoglu, K.; Ozge Dinc, S.; Celal Tunusluoglu, M.

    2010-05-01

    The uniaxial compressive strength (UCS) of rock material is a crucial parameter to be used for design stages of slopes, tunnels and foundations to be constructed in/on geological medium. However, preparation of high quality cores from geological mixtures or fragmented rocks such as melanges, fault rocks, coarse pyroclastic rocks, breccias and sheared serpentinites is often extremely difficult. According to the studies performed in literature, this type of geological materials may be grouped as welded and unwelded birmocks. Success of preparation of core samples from welded bimrocks is slightly better than unwelded ones. Therefore, some studies performed on the welded bimrocks to understand the mechanical behavior of geological mixture materials composed of stronger and weaker components (Gokceoglu, 2002; Sonmez et al., 2004; Sonmez et al., 2006; Kahraman, et al., 2008). The overall strength of bimrocks are generally depends on strength contrast between blocks and matrix; types and strength of matrix; type, size, strength, shape and orientation of blocks and volumetric block proportion. In previously proposed prediction models, while UCS of unwelded bimrocks may be determined by decreasing the UCS of matrix considering the volumetric block proportion, the welded ones can be predicted by considering both UCS of matrix and blocks together (Lindquist, 1994; Lindquist and Goodman, 1994; Sonmez et al., 2006 and Sonmez et al., 2009). However, there is a few attempts were performed about the effect of blocks shape and orientation on the strength of bimrock (Linqduist, 1994 and Kahraman, et al., 2008). In this study, Ankara agglomerate, which is composed of andesite blocks and surrounded weak tuff matrix, was selected as study material. Image analyses were performed on bottom, top and side faces of cores to identify volumetric block portions. In addition to the image analyses, andesite blocks on bottom, top and side faces were digitized for determination of fractal

  1. 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)

  2. 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.

  3. Catalytic soot oxidation in microscale experiments: Simulation of interactions between co-deposited graphitic nanoparticle agglomerates and platinum nanoparticles

    Science.gov (United States)

    Seipenbusch, Martin; Friedlander, Sheldon K.

    2004-12-01

    Continuously regenerating catalytic soot traps are under development to reduce particulate emissions from diesel exhaust. A good understanding of the processes that take place during soot oxidation is needed to optimize diesel soot trap performance. To gain insight into these processes from the perspective of nanoparticle technology, the effects of catalyst particle size and the interparticle distance between soot and catalyst particles were measured. A model catalyst was prepared by depositing Pt nanoparticles on a SiO/SiO2-coated transmission electron microscope (TEM) grid. A soot surrogate composed of graphitic nanoparticle agglomerates generated by laser ablation was deposited on the same surface. This system simulates, morphologically, catalytic soot traps used in practice. The reaction was carried out in a tubular flow reactor in which the gas phase simulated diesel exhaust gas, composed of a mixture of 10% O2 and 1000 ppm NO with the remainder N2. The progress of the carbon nanoparticle oxidation was monitored off-line by analysis of electron microscopy images of the agglomerates before and after reaction. This experimental method permitted the correlation of reaction rate with particle sizes and separation distances as well as catalyst surface area in the direct environs of the soot particles. The experimental results revealed no effect of Pt catalyst particle size in the range 7-31 nm on the rate of reaction. Also observed were a decrease in the rate of reaction with increasing distance between carbon agglomerates and catalyst particles and a linear dependence of the reaction rate on the fractional catalyst surface area coverage.

  4. 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

  5. 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.

  6. Inflammatory MAPK and NF-κB signaling pathways differentiated hepatitis potential of two agglomerated titanium dioxide particles.

    Science.gov (United States)

    Chen, Jin; Zhang, Jianying; Cao, Junmei; Xia, Zongping; Gan, Jay

    2016-03-05

    TiO2 nanoparticles (TiO2NPs) consumption and deposit in liver have possible implications for hepatitis risks. Specific signal dysregulation at early inflammatory responses needs to be characterized in TiO2NP-induced hepatopathy. MAPK and NF-κB signaling pathways are known to participate in inflammation and respond sensitively to chemical agents, making them preferable biomarkers for hepatitis. In the present study, dynamic activation of MAPK and NF-κB pathways were explored by immunoblotting and NF-κB luciferase reporter assay depending on characterization of TiO2NP agglomeration in human HepG2 cells. Inflammatory and cytotoxic potential of TiO2NPs were determined by qRT-PCR and WST-1 assay. AFM and TEM analyses uncovered ultrastructure damages underlying hepatotoxicity of TiO2NPs. Rod-like rutile agglomerated smaller and induced more pronounced cytotoxicity and immunogenicity than anatase. Correspondingly, though both rutile and anatase significantly activated p38, ERK1/2 and NF-κB pathways, rutile accelerated the maximum phosphorylation of ERK1/2 and elevated the potency of IκBα phosphorylation to its bell curve shape in comparison with a lower and sigmoid type of IκBα phosphorylation for anatase. Furthermore, cell elasticity indicated by Young's modulus and adhesion force increased accompanied with mitochondria damage, contributing to signal dysregulation and hepatotoxicity. The results suggested that differential activation of MAPK and NF-κB pathways could be early predictors for distinct hepatitis risks of two agglomerated TiO2NPs.

  7. 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

  8. 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.

  9. Importance of agglomeration state and exposure conditions for uptake and pro-inflammatory responses to amorphous silica nanoparticles in bronchial epithelial cells.

    Science.gov (United States)

    Gualtieri, Maurizio; Skuland, Tonje; Iversen, Tore-Geir; Låg, Marit; Schwarze, Per; Bilaničová, Dagmar; Pojana, Giulio; Refsnes, Magne

    2012-11-01

    Amorphous silica nanoparticles (SiNPs, 30 and 50 nm) and rhodamine-coated SiNPs (50 nm) were examined for their ability to induce pro-inflammatory responses and cytotoxicity in BEAS-2B cells under different experimental conditions. The SiNPs formed micrometre-sized agglomerates in the absence of bovine serum albumin (BSA) in the culture medium, whereas with BSA (0.1%) they were much less agglomerated. All the SiNPs induced IL-6 and IL-8 responses, as measured by ELISA and real-time PCR. The responses were more marked without BSA and higher for the rhodamine SiNPs than the plain ones. Rhodamine SiNPs were not taken up by cells during a 3-h exposure, even though cytokine mRNAs were up-regulated. In conclusion, agglomerated SiNPs induced more potent cytokine responses than the non-agglomerated ones; either due to the agglomeration state per se or more conceivably to a change in surface reactivity against cellular targets due to BSA. Furthermore, cytokine expression was up-regulated independently of SiNP uptake.

  10. Treating waste waters in small agglomerations. The current situation, commitments and alternatives; Depuracion de las aguas residuales en pequenos nuclear. Situacion actual, compromisos y alternativas

    Energy Technology Data Exchange (ETDEWEB)

    Collado Lara, R. [Universidad de Cantabria. (Spain)

    2003-07-01

    In 1991, the European Economic Community issued a directive on urban waste water treatment: (91/27/EEC). This directive laid down that such treatment had to be in place ny the period 2000-2005, depending on the application of different requirements according to the size of the agglomeration and the discharge area. A large number of sewage plants are being built in Spain at the present time, especially in medium-size and large agglomeration (pop>10.000 inhabitants). However, in the smaller agglomeration, over 50% of the waste waters have still to be treated. In agglomerations of less than 10.000 inhabitants, which make up 95% of the municipalities in Spain, it is possible to apply a greater diversity of treatments not all of them conventional that comply with the directive in question. Natural systems and biofilm processes are low-cost solutions that are well adapted to the natural environment. However, conventional technologies are virtually essential in medium-size and large agglomerations, as the lack of space and the exacting demands render them irreplaceable (Collado, 2002). This article describes the distribution of the municipalities in Spain according to the number of inhabitants, the current state os sewage treatment,the commitments made by the European Economic Community and the viable alternatives. Some comments have been added regarding the running of such systems and the need for them to be managed by associations of local councils or regional bodies. (Author)

  11. 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.

  12. 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.

  13. Polystyrene-divinylbenzene stationary phases agglomerated with quaternized multi-walled carbon nanotubes for anion exchange chromatography.

    Science.gov (United States)

    Huang, Zhongping; Wu, Hongwei; Wang, Fengli; Yan, Wenwu; Guo, Weiqiang; Zhu, Yan

    2013-06-14

    This work explores the potential of multi-walled carbon nanotubes as an agglomerated material for ion chromatography stationary phases for the separation of inorganic anions. Polyelectrolytes with quaternary ammonium groups were introduced onto the carbon nanotube surface, based on condensation polymerization of 1,4-butanediol diglycidyl ether (BDDE) and methylamine (MA). Quaternized multi-walled carbon nanotubes (Q-MWCNTs) were electrostatically adsorbed onto the surface of sulfonated polystyrene-divinylbenzene (PS-DVB) beads to generate the anion exchanger, which were confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). A 100mm×4.0mm i.d. column was packed with Q-MWCNTs agglomerated PS-DVB particles, with a capacity of 56μequiv./column. Separation of inorganic anions, such as F(-), Cl(-), NO2(-), Br(-), NO3(-), SO4(2-) and PO4(3-) were performed. The stationary phase was rigid, chemically stable and showed good ion-exchange characteristics.

  14. 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.

  15. 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).

  16. Fractal and agglomeration behavior in Gd and Sm doped CeO{sub 2} nano-crystalline powders

    Energy Technology Data Exchange (ETDEWEB)

    Chavan, S.V. [Applied Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Sastry, P.U. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Tyagi, A.K. [Applied Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)], E-mail: aktyagi@barc.gov.in

    2008-06-12

    Nanocrystalline Gd, Sm doped ceria powders were synthesized by a combustion technique, using glycine as the fuel. These powders, after calcination at 600 {sup o}C, 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.

  17. Understanding the influence of powder flowability, fluidization and de-agglomeration characteristics on the aerosolization of pharmaceutical model powders.

    Science.gov (United States)

    Zhou, Qi Tony; Armstrong, Brian; Larson, Ian; Stewart, Peter J; Morton, David A V

    2010-08-11

    The aim of this study was to investigate the influence of the intrinsic inter-particulate cohesion of model pharmaceutical powders on their aerosolization from a dry powder inhaler. Two cohesive poly-disperse lactose powders with median particle sizes of around 4 and 20 microm were examined. The results showed that after dry coating with magnesium stearate, their flowability, fluidization and de-agglomeration behaviours could be substantially improved, as indicated by powder rheometry, shear testing and laser diffraction aerosol testing. This was achieved by reducing their cohesiveness via surface modification. In contrast to some previous reports, this study demonstrated how powder aerosolization may be improved more significantly and consistently (for widely varying air flow rates) by substantially reducing their inter-particulate cohesive forces. This study contributes to the understanding of the relationship between intrinsic cohesive nature and bulk properties such as flowability, fluidization and de-agglomeration and its impact on their aerosolization, which is fundamental and critical in the optimal design of dry powder inhaler formulations. The intensive mechanical dry coating technique also demonstrated a promising potential to improve aerosolization efficiency of fine cohesive model powders.

  18. 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.

  19. 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

  20. Properties of traffic networks in urban agglomeration%国内外典型城市群交通网络特性对比分析

    Institute of Scientific and Technical Information of China (English)

    王国明; 李夏苗; 胡正东

    2012-01-01

    为了研究城市群交通网络特性,运用ICN dual approach方法构建了以美国东北部大西洋沿岸城市群、日本太平洋沿岸城市群、英国伦敦为核心的城市群、长江三角城市群、京津唐城市群、珠江三角城市群等国内外典型城市群交通网络模型,使用MATLAB和VC++分别对它们的平均度、网络密度、n-聚集系数、平均最短路径、随机网络聚集系数、随机网络平均最短路径、网络结构熵、全局系数等网络特性指标进行计算和比较分析,得到以下结论:a)六个城市群交通网络都具有小世界性而不具有无标度性,一般可以推论城市群交通网络只有小世界性、不具有无标度性;b)六个城市群交通网络都存在着极少道路介数很大,对整个网络的整体性、连通性和安全性意义重大;c)六个城市群交通网络中珠江三角城市群交通网络的整体效率最高,日本太平洋沿岸城市群交通网络结构熵最小,表明其最有序.%In order to research properties of traffic network of urban agglomerations, this paper designed the model of urban agglomeration by ICN dual approach, which included the northeastern United States Atlantic coast urban agglomeration, Japan's Pacific coast urban agglomeration, British London urban agglomeration, Yangtze river delta urban agglomeration, Bei-jing-Tianjin-Tangshan urban agglomeration, Pearl river delta urban agglomeration. And figure out averaged-degree, averaged-clustering coefficient, betweenness centrality of roads with degree and structure entropy based on node betweenness centrality, global coefficient,which show: a) traffic networks have small-world behavior but no scale-free property; b) it is significant for the traffic networks of six urban agglomeration that the betweenness of a few real road is greater; c) the global coefficient of Pearl river delta urban agglomeration is greatest among six urban agglomeration and the entropy of Japan

  1. 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.

  2. 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

  3. 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

  4. 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)

  5. 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)

  6. Advanced development of a pressurized ash agglomerating fluidized-bed coal gasification system: Topical report, Process analysis, FY 1983

    Energy Technology Data Exchange (ETDEWEB)

    None

    1987-07-31

    KRW Energy Systems, Inc., is engaged in the continuing development of a pressurized, fluidized-bed gasification process at its Waltz Mill Site in Madison, Pennsylvania. The overall objective of the program is to demonstrate the viability of the KRW process for the environmentally-acceptable production of low- and medium-Btu fuel gas from a variety of fossilized carbonaceous feedstocks and industrial fuels. This report presents process analysis of the 24 ton-per-day Process Development Unit (PDU) operations and is a continuation of the process analysis work performed in 1980 and 1981. Included is work performed on PDU process data; gasification; char-ash separation; ash agglomeration; fines carryover, recycle, and consumption; deposit formation; materials; and environmental, health, and safety issues. 63 figs., 43 tabs.

  7. Thermoluminescence Properties of Novel Self-Agglomerating CaSO4:Eu Phosphors Obtained by an Environmentally Friendly Method

    Directory of Open Access Journals (Sweden)

    A. R. García-Haro

    2016-01-01

    Full Text Available In this work, we report the thermoluminescence (TL properties of self-agglomerating CaSO4:Eu samples obtained by an environmentally friendly coprecipitation technique. No binding material is needed to form solid CaSO4:Eu samples. Samples exposed to beta particle irradiation exhibit a TL maximum at 473.15 K when a 5 K/s heating rate is used, they are two times more sensitive than the TLD-100 commercial dosimeter, and their lower detection limit was determined to be less than 0.69 mGy. The computerized glow curve deconvolution carried out fitting the residual glow curves from McKeever method revealed that the whole glow curve is composed of four individual TL peaks with intermediate-order kinetics. The main peak order kinetics is b = 1.48. This result agrees with that computed using Chen’s formula.

  8. Particle-size distribution of polybrominated diphenyl ethers (PBDEs) in the urban agglomeration of Thessaloniki, northern Greece

    Science.gov (United States)

    Besis, Athanasios; Botsaropoulou, Elisavet; Voutsa, Dimitra; Samara, Constantini

    2015-03-01

    The size distribution of Polybrominated Diphenyl Ethers (PBDEs) in particle sizes 7.2 μm was measured during the cold and the warm period of the year 2013 at traffic and background sites in the urban agglomeration of Thessaloniki, northern Greece. Mean aggregate concentrations (sum of six particle fractions) of the sum of 12 PBDE congeners (∑12PBDE) were 20.3 and 2.1 pg m-3 at the traffic and the urban background site, respectively, in the cold period exhibiting relative increase (27.1 and 2.4 pg m-3, respectively) in the warm period. At both sampling sites, more than 58% of ∑12PBDE was found to be associated with particles smaller than 0.49 μm in diameter. The outdoor workday inhalation exposure to PBDEs was estimated by calculating daily intake values for respirable, thoracic and inhalable fractions.

  9. Size distribution of agglomerates of milk powder in wet granulation process in a vibro-fluidized bed

    Directory of Open Access Journals (Sweden)

    M. Banjac

    2009-09-01

    Full Text Available Results of experiments on the influence of technological parameters (intensity of vibration, granulation of the liquid feed, temperature of fluidization agent on the change of size distribution, as well as mass mean diameter of the milk powder particles subjected to the wet granulation process (agglomeration in a vibro-fluidized bed granulator are shown in this paper. Using water as a granulation liquid and air as a fluidization agent, it was found that mass mean diameter increases with increase of water feed, intensity of vibration, and decrease of air temperature. Increasing the intensity of vibration and decreasing the air temperature, primarily induces the increase of the dimensions of the initial nuclei. This can be explained on the basis of different influences that these changes (velocity of particle motion, intensity of particle collision, drying rate have on the coalescence of particles with smaller and/or bigger dimensions.

  10. Optical and electrical characterization of tin(II) 2,3-naphthalocyanine thin films containing agglomerated spherical particles

    Energy Technology Data Exchange (ETDEWEB)

    Panicker, Nisha S. [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, Kerala 686560 (India); Gopinathan, T.G. [KE College, Mannanam, Kottayam, Kerala (India); Dhanya, I. [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, Kerala 686560 (India); Menon, C.S., E-mail: prof.menoncs@gmail.co [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, Kerala 686560 (India)

    2010-11-01

    Vacuum deposited tin(II)2,3-naphthalocyanine (SnNc) crystalline thin films were produced. The structural properties of the thin films were characterized using Fourier transform infrared spectroscopy (FTIR), which reveals traces of organic compounds within the as-deposited films. Surface morphological studies by scanning electron microscopy (SEM) were done and the films were found to be grainy in nature, comprising of small agglomerated spherical particles. Heat treatment decreased the optical band gap of the films due to the dependence of dilatation of the lattice and/or electron-lattice interaction. The electrical conductivity of the films at various heat treated stages shows that SnNc has a better conductivity by 10-50 times that of its earlier reported phthalocyanine counterpart and the activation energy was found to increase with annealing temperature.

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

    Science.gov (United States)

    Huang, Qunfang; Lu, Yuqi

    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 (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. PMID:26225986

  12. 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.

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

    Science.gov (United States)

    Huang, Qunfang; Lu, Yuqi

    2015-07-27

    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.

  14. Water resources management in the urban agglomeration of the Lake Biwa region, Japan: An ecosystem services-based sustainability assessment.

    Science.gov (United States)

    Chen, Xiaochen; Chen, Yuqing; Shimizu, Toshiyuki; Niu, Jia; Nakagami, Ken'ichi; Qian, Xuepeng; Jia, Baoju; Nakajima, Jun; Han, Ji; Li, Jianhua

    2017-05-15

    An innovative ecosystem services-based sustainability assessment was conducted in the important urban agglomeration of the Lake Biwa region, Japan, covering the time period from 1950 to 2014. A 22-indicator system was established that was based on the major ecosystem services of Lake Biwa and its water courses, i.e., provisioning services regarding aquatic products and water; regulating services regarding floods and water quality; cultural services regarding recreation and tourism, scientific research, and environmental education; and supporting services regarding biodiversity. First, changes in the eight ecosystem services were discussed together with the considerable experience and difficult lessons that can be drawn from the development trajectory. Next, with the indicators rearranged according to sustainability principles, the regional sustainability over the past six-plus decades was assessed. In general, this urban agglomeration has been progressing in terms of its sustainability, although economic and social development was achieved at the cost of environmental degradation in the past, and the current economic downturn is hurting the balanced development and integrated benefits. The results lead directly to recommendations for regional development, especially in terms of economic rejuvenation, from the perspective of improving management of Lake Biwa's water resources. Moreover, the relevant knowledge is educational and inspirational for other places in the world that are facing similar development issues. For example, the effective and even pioneering countermeasures that have been taken against environmental degradation, as well as the participation and collaboration of multiple stakeholders, could be useful as a model. Moreover, the study invites increased understanding of ecosystem vulnerability to anthropogenic devastation and emphasizes the priority of precautionary measures over countermeasures in the context of holistic urban planning and sustainable

  15. 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.

  16. Design of sustained release fine particles using two-step mechanical powder processing: particle shape modification of drug crystals and dry particle coating with polymer nanoparticle agglomerate.

    Science.gov (United States)

    Kondo, Keita; Ito, Natsuki; Niwa, Toshiyuki; Danjo, Kazumi

    2013-09-10

    We attempted to prepare sustained release fine particles using a two-step mechanical powder processing method; particle-shape modification and dry particle coating. First, particle shape of bulk drug was modified by mechanical treatment to yield drug crystals suitable for the coating process. Drug crystals became more rounded with increasing rotation speed, which demonstrates that powerful mechanical stress yields spherical drug crystals with narrow size distribution. This process is the result of destruction, granulation and refinement of drug crystals. Second, the modified drug particles and polymer coating powder were mechanically treated to prepare composite particles. Polymer nanoparticle agglomerate obtained by drying poly(meth)acrylate aqueous dispersion was used as a coating powder. The porous nanoparticle agglomerate has superior coating performance, because it is completely deagglomerated under mechanical stress to form fine fragments that act as guest particles. As a result, spherical drug crystals treated with porous agglomerate were effectively coated by poly(meth)acrylate powder, showing sustained release after curing. From these findings, particle-shape modification of drug crystals and dry particle coating with nanoparticle agglomerate using a mechanical powder processor is expected as an innovative technique for preparing controlled-release coated particles having high drug content and size smaller than 100 μm.

  17. 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.)

  18. 蕾丝状富Co团聚组织与Co粉中硬团聚现象研究%A Lacelike Cobalt-rich Agglomeration Microstructure and Solid Agglomeration in Cobalt Powder

    Institute of Scientific and Technical Information of China (English)

    张立; 杨爱军; 解明伟; 南晴; 冯于平

    2012-01-01

    硬质合金顶锤是WC-Co合金大制品与极端服役工况的典型代表.服役过程中硬质合金顶锤的异常失效是困扰超硬材料与硬质合金顶锤生产企业的棘手问题.本文采用扫描电镜、能谱分析以及X射线衍射分析等研究手段对硬质合金顶锤碎片与硬质合金生产用Co粉进行了观察与分析,报道了异常失效顶锤碎片微观组织结构中存在含K、Na、Ca、S、Cl、O等杂质元素、周长超过100 μm的脆性蕾丝状富Co团聚组织,以及Co粉中存在因杂质与还原烧结效应导致的、外表光滑、尺度高达10 μm的致密硬团聚微观缺陷.其中,富Co团聚组织中K、Na、Ca、S、Cl等杂质元素的总质量分数高达2.8%~3.45%.通过引证关联分析,认为两种缺陷之间存在一定的相关性,建议硬质合金生产企业在采购Co粉时必须重视对粉末微观质量的分析与检测.%Cemented carbide anvil is a typical representative of the large WC-Co products and harsh service situations. Abnormal failure of cemented carbide anvil has puzzled both the super had material and cemented carbide anvil manufacturers. Scanning electronic microscope, energy dispersive spectrometer and X-ray diffractometer were used for the analysis of typical fragments of cemented carbide anvil and cobalt powders used for the production of cemented carbide. A brittle lacelike cobalt-rich agglomeration microstructure containing impurity elements, e.g. K, Na, Ca, S, Cl and O with a perimeter over 100 祄 in the fragment of cemented carbide anvil was observed. Solid agglomerations with smooth appearance and a size as large as 10 祄 in cobalt powders, caused by the combined effects of impurity elements and sintering during the reduction process were reported. The total mass fraction of impurity elements K, Na, Ca, S, Cl in the cobaltr rich agglomeration microstructure reached as high as 2.8%~3.45%. It is suggested that there exists a relationship between these two

  19. Urban Tourism to Urban Agglomeration Tourism: A Deepening Systematic Research%城市旅游到城市群旅游的系统研究

    Institute of Scientific and Technical Information of China (English)

    虞虎; 陆林; 朱冬芳; 曾琪洁

    2012-01-01

    城市群正成为全球经济竞争的基本地域单元,城市群旅游研究正处于起步阶段。本文采用文献分析法系统总结了城市旅游和城市群旅游的主要研究内容,分析了城市旅游向城市群旅游转向的推动因素和路径,最后讨论了城市群旅游发展存在的问题和趋势。研究认为,旅游主要在城市商业区塑造和城市滨水空间开发、经济与就业增长、对城市规划的补充、促进文化交流、提高城市整体形象、引导或加速城市环境质量的改善6个方面促进城市发展。旅游与城市融合发展具有互利性、动态性。城市群旅游研究主要集中在旅游发展带动了城市群旅游产业集聚、交通条件提升、空间结构优化、旅游合作4个方面。全球化与地方化趋势是城市群旅游形成的重要动力,城镇体系是空间建构的物质基础,旅游产品和市场需求的多样化及差异化是推力,以快速交通为代表的交流手段是科技支撑,政府对城市群旅游发展起到主要协调作用,这5个因素推动着城市旅游向城市群旅游的转变。城市群旅游强调政府和市场调控下多系统、多要素下的动态相互作用,城市群研究是城市旅游研究的深人。对城市旅游、城市群旅游内容进行系统归纳可为今后城市群旅游研究奠定基础,拓展旅游地理学研究范围。%Urban tourism is one of the most important contents of tourism research. Urban agglomeration is be- coming a basic unit which is playing a significant role in global economic competition, but the research on ur- ban agglomeration tourism is in the initial stage. This article, by using the literature analysis method, firstly sum- marizes the main research content of urban tourism and urban agglomeration tourism. Then it analyzes the re- search trend path from urban tourism to urban agglomeration tourism. Finally the influencing factors of urban

  20. Bruchpilot in ribbon-like axonal agglomerates, behavioral defects, and early death in SRPK79D kinase mutants of Drosophila.

    Directory of Open Access Journals (Sweden)

    Vanessa Nieratschker

    2009-10-01

    Full Text Available Defining the molecular structure and function of synapses is a central theme in brain research. In Drosophila the Bruchpilot (BRP protein is associated with T-shaped ribbons ("T-bars" at presynaptic active zones (AZs. BRP is required for intact AZ structure and normal evoked neurotransmitter release. By screening for mutations that affect the tissue distribution of Bruchpilot, we have identified a P-transposon insertion in gene CG11489 (location 79D which shows high homology to mammalian genes for SR protein kinases (SRPKs. SRPKs phosphorylate serine-arginine rich splicing factors (SR proteins. Since proteins expressed from CG11489 cDNAs phosphorylate a peptide from a human SR protein in vitro, we name CG11489 the Drosophila Srpk79D gene. We have characterized Srpk79D transcripts and generated a null mutant. Mutation of the Srpk79D gene causes conspicuous accumulations of BRP in larval and adult nerves. At the ultrastructural level, these correspond to extensive axonal agglomerates of electron-dense ribbons surrounded by clear vesicles. Basic synaptic structure and function at larval neuromuscular junctions appears normal, whereas life expectancy and locomotor behavior of adult mutants are significantly impaired. All phenotypes of the mutant can be largely or completely rescued by panneural expression of SRPK79D isoforms. Isoform-specific antibodies recognize panneurally overexpressed GFP-tagged SRPK79D-PC isoform co-localized with BRP at presynaptic active zones while the tagged -PB isoform is found in spots within neuronal perikarya. SRPK79D concentrations in wild type apparently are too low to be revealed by these antisera. We propose that the Drosophila Srpk79D gene characterized here may be expressed at low levels throughout the nervous system to prevent the assembly of BRP containing agglomerates in axons and maintain intact brain function. The discovery of an SR protein kinase required for normal BRP distribution calls for the

  1. Empirical Study on the Relationship between Agglomeration and Economic Growth in Urban Agglomeration in the Middle Reaches of Yangtze River:Based on Dynamic Panel GMM Analysis%长江中游城市群产业集聚与经济增长的实证研究*--基于动态面板GMM估计的分析

    Institute of Scientific and Technical Information of China (English)

    田超; 王磊

    2015-01-01

    Industrial agglomeration and economic growth always go together. Agglomeration brings positive externalities to economy, and it may also generates congestion effect at the same time. Based on theoretical possibility, this paper proposes nonlinear relationship between industrial agglomeration and economic growth, and introduces the GMM estimation on the relationship by using industrial data of urban agglomeration in the middle reaches of Yangtze river from 2006 to 2011. Regression results show that the overall relationship between industrial agglomeration and economic growth presents inverted U-shape. However,when we classify the industry into four parts, the results change. To be specific, resource-intensive industries present inverted U-shape, but labor-intensive, capital-intensive and technology-intensive industries present U-shape. In order to maintain the sustainable development of agglomeration and industrial healthy growth, and to enhance the competitiveness of urban agglomeration, governments should adjust and optimize the industrial structure based on the differences of industry characteristics and agglomeration effect.%产业集聚与经济增长是一个相伴相生的过程,产业集聚在带来正外部性的同时,也可能产生拥塞效应。基于理论上的可能性,文章提出产业集聚与经济增长存在非线性关系,并利用长江中游城市群2006—2011年工业数据,采用动态面板GMM估计的分析方法对产业集聚与经济增长的关系进行了实证分析。结果表明,整体上工业集聚与经济增长呈现倒U型关系,但是对产业进一步分类后发现,资源密集型产业的集聚与经济增长存在倒U型关系,劳动密集型、资本密集型和技术密集型产业的集聚与经济增长存在U型关系。据此,政府应该根据行业特性和产业集聚效应的差异,优化调整产业结构,以利于集聚的可持续发展和产业的健康成长,增强城市群的竞争力。

  2. 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

  3. Insights into the inner structure of high-nickel agglomerate as high-performance lithium-ion cathodes

    Science.gov (United States)

    Yang, Cheng-Kai; Qi, Li-Ya; Zuo, Zicheng; Wang, Ru-Na; Ye, Meng; Lu, Jing; Zhou, Heng-Hui

    2016-11-01

    In this paper, the intrinsic impact of inner structure features on the electrochemical performances of LiNi0.6Co0.2Mn0.2O2 cathodes is for the first time systematically investigated. Three different spherical Ni0.6Co0.2Mn0.2(OH)2 precursors are successfully synthesized by controlling pH values and ammonia concentrations. Interestingly, via a further lithiation process, the final cathodes can gradually inherit the structural features, showing distinct particle arrangement and genetic orientation characteristics in the inner structures. Such a hereditary property can be well reined for customizing the grain-orientation, helping the growth of the inert crystal direction, reducing cation mixing and exposing the high active (100) or (010) lattice planes for lithiation/delithiation processes via an intrinsical way. The degree of grain-orientation of the primary particles turns out to be a critical factor in determining the long-term stability and power performances. Due to the reduced cation mixing degree and favorable lithium diffusion pathways, the ordered agglomerates with the grain growth along with [003] direction exhibit superior rate capability and good cycle stability.

  4. 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.

  5. 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.

  6. 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."

  7. 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.

  8. Removal of oxide nanoparticles in a model wastewater treatment plant: influence of agglomeration and surfactants on clearing efficiency.

    Science.gov (United States)

    Limbach, Ludwig K; Bereiter, Robert; Müller, Elisabeth; Krebs, Rolf; Galli, René; Stark, Wendelin J

    2008-08-01

    The rapidly increasing production of engineered nanoparticles has created a demand for particle removal from industrial and communal wastewater streams. Efficient removal is particularly important in view of increasing long-term persistence and evidence for considerable ecotoxicity of specific nanoparticles. The present work investigates the use of a model wastewater treatment plant for removal of oxide nanoparticles. While a majority of the nanoparticles could be captured through adhesion to clearing sludge, a significant fraction of the engineered nanoparticles escaped the wastewater plant's clearing system, and up to 6 wt % of the model compound cerium oxide was found in the exit stream of the model plant. Our study demonstrates a significant influence of surface charge and the addition of dispersion stabilizing surfactants as routinely used in the preparation of nanoparticle derived products. A detailed investigation on the agglomeration of oxide nanoparticles in wastewater streams revealed a high stabilization of the particles against clearance (adsorption on the bacteria from the sludge). This unexpected finding suggests a need to investigate nanoparticle clearance in more detail and demonstrates the complex interactions between dissolved species and the nanoparticles within the continuously changing environment of the clearing sludge.

  9. 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."

  10. Organic market gardening around the Paris agglomeration: agro-environmental performance and capacity to meet urban requirements.

    Science.gov (United States)

    Anglade, Juliette; Medina, Michael Ramos; Billen, Gilles; Garnier, Josette

    2016-05-04

    Organic market gardening is often promoted by urban municipalities as a way to resource part of the food supply, creating new social links and protecting groundwater resources. The agronomical and environmental performance of six commercial organic market gardening farms supplying vegetables in Paris were evaluated and compared with other vegetable production systems. When expressed in terms of protein production, the yield of these systems appears rather low compared with the productive capacity of open-field organic cropping systems where vegetable production is inserted into rotation with other crops. Moreover, the requirement of producing infiltrated water meeting the drinking water standards seriously limits the allowable rate of fertilisation, thus limiting production. The data reported herein show that to supply the amount of vegetables required by the Paris agglomeration (12 million inhabitants) only by organic market gardening, 160,000-205,000 ha, i.e. 28-36 % of the agricultural area of the surrounding Ile-de-France region, would be required. We conclude that organic market gardening is only one of several other farming systems which can contribute to a re-localised supply of vegetables to large cities.

  11. 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.

  12. Graph-based active learning of agglomeration (GALA): a Python library to segment 2D and 3D neuroimages.

    Science.gov (United States)

    Nunez-Iglesias, Juan; Kennedy, Ryan; Plaza, Stephen M; Chakraborty, Anirban; Katz, William T

    2014-01-01

    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 to network reconstruction is to perform (error-prone) automatic segmentation of EM images, followed by manual proofreading by experts to fix errors. We have 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 current limitations of the gala library and how we intend to address them.

  13. Risk assessment of children’s exposure to potentially harmful elements (PHE in selected urban parks of the Silesian agglomeration

    Directory of Open Access Journals (Sweden)

    Kicińska Alicja

    2016-01-01

    Full Text Available The author determined the total contents of selected elements potentially hazardous for health (PHE: As, Be, Cd, Co, Cu, Ni and Sn in soils, sand of sandboxes and airborne dust collected in three urban parks of the Silesian agglomeration. The upper limit of Cd content (a Polish regulation was exceeded in the soils of two largest and most frequented parks, the Silesian Park and the Kościuszko Park. The mean Cd contents in soils are 9 and 7 mg/kg, respectively. The metal contents of the sand from sandboxes are generally much lower than those of the soils: Cu 28 times on average, As 13 times, and Cd and Ni around 4 times, while the Co and Sn contents of sand are comparable with those of soils. Airborne dusts are a significant source of metals: they contain Cd (1–20 mg/kg, Co (2–17 mg/kg and Cu (6–143 mg/kg. The quotients of the health risk indicate a potential health risk caused by As, Cd and Ni for children, particularly those with a low (below 15 kg body weight. The risk level of 1–4% PTMDI (Provisional Maximum Tolerable Daily Intake origins from an accidental swallowing of soil.

  14. 超高频RFID集聚识别技术的研究%Study on agglomeration recognition of UHF RFID

    Institute of Scientific and Technical Information of China (English)

    童廷洋

    2014-01-01

    集聚识别技术是针对超高频 RFID 高度密集的射频标签无法全部识别的问题,通过采用超高频远距离电子标签、射频识别金属屏蔽效应和交变磁场集聚识别等技术,克服外部标签干扰和内部射频识别空腔效应,降低或减少遮挡盲点和叠加盲点,快速识读全部密集标签,同时不误读任何标签。%Agglomeration recognition technology can fast read all dense label , solve the problem that highly dense UHF tag cannot be all recognition. The technology uses several techniques including ultra high frequency electronic tags , metal shielding effect and alternating magnetic field. The technology overcomes the effects that external tag interference and internal RFID cavity effect , which reduce shading blind spots and superposition blind spot.

  15. Comparison of reduction disintegration characteristics of TiO2-rich burdens prepared with sintering process and composite agglomeration process

    Institute of Scientific and Technical Information of China (English)

    Zheng-wei Yu; Guang-hui Li; Chen Liu; Feng Zhou; Zhi-wei Peng; Tao Jiang

    2016-01-01

    To reveal the impact of the composite agglomeration process (CAP) on the reduction disintegration properties of TiO2-rich iron-making burden for a blast furnace, the reduction disintegration indices (RDIs), mineral constituents, and microstructure of the products pre-pared by the CAP and the traditional sintering process (TSP) were investigated. The results showed that, compared to the sinter with a ba-sicity 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.

  16. 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

  17. Role of the effective electrical conductivity of nanosuspension in the generation of TiO2 agglomerates with electrospray

    Energy Technology Data Exchange (ETDEWEB)

    Modesto-Lopez, Luis B. [Washington Univ., St. Louis, MO (United States); Biswas, Pratim [Washington Univ., St. Louis, MO (United States)

    2010-04-26

    Suspensions with varying volume fraction of TiO2 nanoparticles and ionic strength were electrosprayed to obtain agglomerates of different characteristics, which were then deposited to produce films with tailored morphology, thickness, and porosity. The role of the nanoparticle volume fraction in both the effective electrical conductivity of TiO2 nanosuspensions and the control of the size of agglomerates produced by electrospray was investigated. A simple modified equation for the effective electrical conductivity of TiO2 nanoparticle suspensions was derived. The equation, which accounted for nanoparticles' diffuse ionic layer and their agglomeration in a liquid, showed that the effective electrical conductivity is not only a function of the liquid and particle conductivities, and the particle volume fraction but also a function of both the thickness of the adsorbed ionic layer on the particles and the particle size. Gradual increase of particle volume fraction resulted in an increase in the suspension's effective electrical conductivity, when the initial liquid conductivity was in the range of 10-4–10-3 S m-1. When the liquid conductivity was in the range of 10-3–10-2 S m-1; however, addition of particles did not have any significant effect on the effective electrical conductivity. Control over the size of the TiO2 nanoparticle agglomerates was achieved by electrospraying suspensions with liquid electrical conductivity of the order of 10{sup -3} S m-1 and by varying the particle volume fraction. Electrospray deposition of suspensions with TiO2 volume fraction=0.04% resulted in a more compact film with lower porosity and showed better water-splitting performance.

  18. Processes of Defragmentation, Thermocapillary Extraction and Agglomeration of Ultradispersed Gold from Mineral Raw Materials and Technogenic Products within Laser Radiation Field

    Directory of Open Access Journals (Sweden)

    A.P. Kuzmenko

    2013-10-01

    Full Text Available According to the analysis of the results of complex studies of mineral raw materials and man-handle products containing ultra-dispersed gold, silver, and platinum before and after laser treatment, a qualitative physical model which explains the origin of thermal processes occurring under the action of laser radiation is proposed. It is noted that laser treatment of those materials generates processes of defragmentation, thermocapillary extraction, and agglomeration of micro-and nanoinclusions of these metals.

  19. 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.

  20. 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)

  1. 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...... process than for the polymer coating process, under similar process conditions. This is investigated further in this second part and concluded to be due to differences in coating solution stickiness, rather than differences in bulk viscosities. Furthermore, results show that it is possible to optimize...... the PVA-TiO2 coating formulation and process to achieve a low tendency of agglomeration, similar to that of the salt coating process. The best results for the PVA-TiO2 solution are obtained by substituting the PVA-TiO2 in equal amounts with Neodol 23-6.5 and further reducing the pH value in the coating...

  2. 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.

  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. Study and Application of Shannon Entropy in Analysis of Flow Behavior of Cohesive Particle Agglomerations%粘附性颗粒流化特性研究及信息熵分析

    Institute of Scientific and Technical Information of China (English)

    郑建祥; 朱秀丽

    2015-01-01

    建立粘附性颗粒气固两相双流体模型,依据粘附性颗粒碰撞动力学,推导固相粘度系数和聚团压力等物性参数,并采用力平衡模型估算聚团当量直径。模拟流化床内粘附性颗粒聚团流动特性,结果表明,床内流动为S型环核流动结构,大聚团主要聚集在床层底部高浓度区,上部稀相区,聚团直径较小。应用shnnon信息熵分析粘附性颗粒流动的混沌特性,得出在床层上部,聚团碰撞较剧烈。%Flow behavior of cohesive particle agglomerations in CFB was numerically studied by means of a two-fluid flow model considering dynamics of collision between cohesive particles. The model of particle viscos-ity and pressure of particle agglomerations were proposed,and the size of agglomerations was estimated by mod-el proposed by Zhou(1998) from force balance acting on an agglomerations. The results of simulation showed that the flow behavior of cohesive particle agglomerations was the annulus-dense core flow structure of “S”type. The big particle agglomerations mainly appeared in the bottom of riser and walls. While the small particle agglomerations appeared in dilute regime of center of riser. The chaotic characteristics of the flow behavior of cohesive particles were analyzed using by Shannon entropy. The result show in upper bed, the collisions between agglomerations were tempestuousness.

  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. 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.

  7. 空间集聚经济:理论演进、分类与测度指标%SPATIAL AGGLOMERATION ECONOMY:THEORETICAL DEVELOPMENT, CLASSIFICATION AND MEASUREMENT INDEX

    Institute of Scientific and Technical Information of China (English)

    方文超; 马怀礼

    2013-01-01

    Spatial Agglomeration Economy is a kind of spatial externality in essence, it can be classified as Static Agglomeration Economy and Dynamic Agglomeration Economy. This paper starts from the theoretical development of Spatial Agglomeration Economy, explains the implications, characteristics and interior relations between the two kinds of agglomeration economies. The research on Agglomeration Economies in China is still on introduction stage, Especially the empirical research is weak for lack of instruments and data. So then this paper summarizes and explains the Measurement Indexes in detail.%  空间集聚经济本质是一种空间外部性,它可以分为静态集聚经济和动态集聚经济两类。文章从研究集聚经济的理论演进出发,详细阐述了两种集聚经济形态的含义、特征及内在关联性;国内对空间集聚经济的研究仍处于引入阶段,特别是实证研究仍非常薄弱,主要原因在于数据及实证工具的缺乏。最后,对空间集聚经济的测度指标做了归纳总结,并做了详细解释。

  8. 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

  9. 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

  10. 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.

  11. The Relationship between Industrial Agglomeration and'Agglomeration Effect' :the Mediated Moderation Variable Model%集聚度与"集聚效应"的关系研究——基于有中介的调节变量模型

    Institute of Scientific and Technical Information of China (English)

    张扬; 解柠羽

    2016-01-01

    Constructed the relationship model between the industrial concentration degree and agglomeration effect with knowledge spillover as mediator , the administrative exit barriers as moderatior , using the EVIEWS6.0 fitting regression equation to estimate of the pa-rameters in the model . The main conclusion is:the industrial concentration degree positive influencing the concentrating effect;the effect of agglomeration degree to knowledge spillover is not significant;administrative withdrawal barrier regulating the relationship between degree of agglomeration and cluster effect , that the stronger the administrative barriers to exit , the weaker the positive correlations between degree of agglomeration and agglomeration effect . So , this paper puts forward the appropriate control the degree of agglomeration , avoiding blind expansion of scale , making relevant policy to further promote and expand the cluster enterprise knowledge spillover , and the policy sugges-tions to reduce or eliminate administrative barrier , etc .%本文构建了以知识溢出为中介变量、以行政性退出壁垒为调节变量的产业集聚度与集聚效应关系模型 ,运用EVIEWS6.0拟合回归方程实现对模型中各参数的估计.得出的主要结论是 :产业集聚度正向影响集聚效应 ;集聚度对知识溢出的影响不显著 ;行政性退出壁垒调节集聚度与集聚效应的关系 ,即行政性退出壁垒越强 ,集聚度与集聚效应的正向关系越弱.为此 ,提出了适当控制集聚度、制定相关政策进一步促进和扩大集聚企业的知识溢出、降低或消除行政性退出壁垒、探索推进竞争类国企混合所有制改革等政策建议.

  12. 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

  13. From Agglomerates of Spheres to Irregularly Shaped Particles: Determination of Dynamic Shape Factors from Measurements of Mobility and Vacuum Aerodynamic Diameters

    Energy Technology Data Exchange (ETDEWEB)

    Zelenyuk, Alla; Cai, Yong; Imre, Dan G.

    2006-03-01

    With the advert of aerosol instrumentation it has become possible to simultaneously measure individual particle mobility and vacuum aerodynamic diameters. For spherical particles these two diameters yield individual particle density. In contrast, assigning a physical meaning to the mobility or aerodynamic diameter of aspherical particles is not straightforward. This paper presents an experimental exploration of the effect of particle shape on the relationship between mobility and vacuum aerodynamic diameters. We make measurements on systems of three types: 1) Agglomerates of spheres, for which the density and the volume are known; 2) Ammonium sulfate, sodium chloride, succinic acid and lauric acid irregularly shaped particles of known density; and 3) Internally mixed particles, containing organics and ammonium sulfate, of unknown density and shape. For agglomerates of spheres we observed alignment effects in the DMA and report the first measurements of the dynamic shape factors (DSFs) in free molecular regime. We present here the first experimental determination of the DSF of ammonium sulfate particles. We find for ammonium sulfate particles a DSF that increases from 1.03 to 1.07 as particle mobility diameter increases from 160 nm to 500 nm. Three types of NaC1 particles were generated and characterized: nearly spherical particles with DSF of ~1.02; cubic with DSF that increases from 1.065 to 1.17 as particle mobility diameter increases from 200 nm to 900 nm; and compact agglomerates with DSF 1.3-1.4. Organic particles were found very nearly spherical. The data suggest that particles composed of binary mixtures of ammonium sulfate and succinic acid have lower dynamic shape factors than pure ammonium sulfate particles. However, for internally mixed ammonium sulfate and lauric acid particles we cannot distinguish between nearly spherical particles with low density and particles with DSF of 1.17.

  14. New Industrial Agglomeration Theory: An Analysis Perspective of Knowledge Capital%新产业集聚论: 知识资本的分析视角

    Institute of Scientific and Technical Information of China (English)

    曲振涛; 李松

    2016-01-01

    传统经济增长理论中的要素 (资本、 土地、 劳动力) 呈现的是报酬递减的规律, 而知识作为新经济增长理论的核心要素, 具有报酬递增的优势. 本文引入广义知识资本的概念, 将知识作为经济增长的关键变量, 从知识存量与知识转化能力方面提出了 "知识资本-分工-集聚"循环累积的关联机制, 从知识资本视角对产业集聚的生成机制进行了重新诠释, 并指出了新常态下中国产业集聚的基础与条件.%The elements of traditional economic growth theory, for example the capital, the land, and the labor, are presented in the law of diminishing returns.But as the core element of the new economic growth theory, the knowledge has the advantage of increasing returns.The article introduces the concept of generalized knowledge capital, and takes knowledge as the key variable of economic growth.From the stock of knowledge and knowledge transfer capabilities, the paper proposes a"knowledge capital-the division of labor-agglomeration" cycle accumulated mechanism, reinterprets formation mechanism of industrial agglomeration from the perspective of intellectual capital, and points out the foundation and conditions of Chinese industrial agglomeration under the new normal.

  15. 我国城市群发展的差异化战略分析%Analysis on Differentiation Strategy of the Urban Agglomeration Development in China

    Institute of Scientific and Technical Information of China (English)

    苏雪串; 舒银燕

    2012-01-01

    As a spatial form, urban agglomeration is the space unit to the urbanization and regional economy. The formation and development of urban agglomeration may generally experience four regular stages: dispersion, polarization, diffusion and maturation. The size and structure of cities and the degree of co - operation among cit- ies are quite different in the four stages. So, according to the regional economic level basis, different urban ag- glomerations should have different development strategies. And from this, we may find that the development of ur- ban agglomerations in the western, middle and eastern part of China are quite different. Based on the above - mentioned theory analysis, we finally consider that the development strategy of urban agglomeration in the eastern china should focus on improving the industrial division among cities. While to the western part of China, the strat- egy should focus on constructing the central city and improving the city system.%城市群是城市化和经济发展的一种地域单元或空间形态。城市群的形成和发展具有阶段性规律,依次会经过城市分散、极化、扩散及成熟四个阶段。不同阶段城市群内城市规模结构、城市之间分工协作程度等特征不同。因此,在不同经济发展水平的区域,城市群发育程度不同,就应选择差异化发展战略。我国东中西部城市群所依托的区域经济基础的差异导致各区域城市群的发育程度不同。笔者认为,根据其各自所处的发展阶段,东部地区城市群发展的战略重点是优化城市之间的产业分工,而西部地区城市群发展则应重点培育中心城市、完善城市规模体系。

  16. 集聚效应、人口流动与城市增长%Agglomeration Economies, Migration and Cities’ Growth

    Institute of Scientific and Technical Information of China (English)

    杜旻; 刘长全

    2014-01-01

    认识驱动城市增长的经济力量是发挥市场在城镇化与城镇体系优化中决定性作用的基础。本文在集聚效应框架下,构建包含技术外部性与货币外部性影响的单区域和多区域人口迁移模型,使用2000~2011年261个城市的面板数据,通过引入衡量不同来源外部性的集聚因素,检验并确认了集聚效应在中国城市增长中的作用。研究发现:以城市人口规模衡量的技术外部性与城市人口增长率之间存在“U”型曲线关系,但是大多数城市处于曲线的左侧,城市增长率因城市规模增长而下降;以城市人口密度衡量的技术外部性与城市增长率之间表现出的倒“U”型曲线关系在统计上不显著;新经济地理理论所强调的货币外部性是驱动中国城市增长的重要力量;传统人口迁移理论中决定收入预期的工资和失业率对城市增长也有显著影响。%To learn the driving force of the cities’ growth is fundamental for market mechanism to play decisive role in urbanization and urban systems optimization. This paper first constructs singleregion and multiregion urban growth models incorporating technological and pecuniary externalities, then to check and verify the effects of agglomeration economies on China’ s cities growth by using a panel data of 261 cities between 2000 and 2011. Results show, technological externalities measured by city population have Ushape relation with the growth rate of urban population, but most cities lie on the left side of the curve, which means urban population growth rates go down while cities grow larger; technological externalities measured by city population density have a statistically insignificant inverse Ushape relation with urban population growth rates; pecuniary externalities measured by market potential have significant positive effects on the growth rate of urban population;wages and unemployment rate, which decide the

  17. Evaluation of Sound Absorption Property of Agglomerated Cork Board%软木聚结材料的吸声性能评价

    Institute of Scientific and Technical Information of China (English)

    贾汀; 宋孝周; 雷亚芳

    2012-01-01

    为了考察软木聚结材料自身及其贴覆于3种人造板基材后的吸声性能,探究将其用于减少室内环境噪音的可行性,采用驻波管法测定其吸声系数.结果表明:在一定范围内,软木聚结材料吸声系数与其厚度成正比,与密度成反比;在人造板基材正面贴覆软木聚结材料,其吸声效果优于基材背面贴覆.可依据实际应用需要,选择合适的贴面方式、材料密度和厚度.%In order to evaluate the performance of agglomerated cork boards for indoor sound barriers, the sound absorption coefficients of the panels laminated, with different agglomerated cork boards, were measured by the standing wave tube method. The results showed that the sound absorption coefficient of the samples increased with increased thickness or decreased density.

  18. A ∼32–70 K FORMATION TEMPERATURE RANGE FOR THE ICE GRAINS AGGLOMERATED BY COMET 67 P/CHURYUMOV–GERASIMENKO

    Energy Technology Data Exchange (ETDEWEB)

    Lectez, S.; Simon, J.-M.; Salazar, J. M. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303, CNRS-Université de Bourgogne Franche Comté, Dijon (France); Mousis, O. [Aix Marseille Université, CNRS, Laboratoire d’Astrophysique de Marseille (LAM), UMR 7326, F-13388 Marseille (France); Picaud, S. [Institut UTINAM, UMR 6213, CNRS-Université de Bourgogne Franche Comté, Besançon (France); Altwegg, K.; Rubin, M., E-mail: jmsimon@u-bourgogne.fr [Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern (Switzerland)

    2015-05-20

    Grand Canonical Monte Carlo simulations are used to reproduce the N{sub 2}/CO ratio ranging between 1.7 × 10{sup −3} and 1.6 × 10{sup −2} observed in situ in the Jupiter-family comet 67 P/Churyumov–Gerasimenko (67 P) by the ROSINA mass spectrometer on board the Rosetta spacecraft. By assuming that this body has been agglomerated from clathrates in the protosolar nebula (PSN), simulations are developed using elaborated interatomic potentials for investigating the temperature dependence of the trapping within a multiple-guest clathrate formed from a gas mixture of CO and N{sub 2} in proportions corresponding to those expected for the PSN. By assuming that 67 P agglomerated from clathrates, our calculations suggest the cometary grains must have been formed at temperatures ranging between ∼31.8 and 69.9 K in the PSN to match the N{sub 2}/CO ratio measured by the ROSINA mass spectrometer. The presence of clathrates in Jupiter-family comets could then explain the potential N{sub 2} depletion (factor of up to ∼87 compared to the protosolar value) measured in 67 P.

  19. 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.

  20. 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.

  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. Extrinsic lactose fines improve dry powder inhaler formulation performance of a cohesive batch of budesonide via agglomerate formation and consequential co-deposition.

    Science.gov (United States)

    Kinnunen, Hanne; Hebbink, Gerald; Peters, Harry; Huck, Deborah; Makein, Lisa; Price, Robert

    2015-01-15

    The aim of the study was to investigate how the fine particle content of lactose carriers prepared with different types of lactose fines regulates dry powder inhaler (DPI) formulation performance of a cohesive batch of micronised budesonide. Budesonide formulations (0.8 wt%) were prepared with three different lactose carriers (Lactohale (LH) LH100, 20 wt% LH210 in LH100 and 20 wt% LH300 in LH100). Fine particle fraction of emitted dose (FPFED) and mean mass aerodynamic diameter (MMAD) of budesonide was assessed with a Next Generation Impactor (NGI) using a Cyclohaler at 90 l/min. Morphological and chemical characteristics of particles deposited on Stage 2 were determined using a Malvern Morphologi G3-ID. The results indicate that increasing concentration of lactose fines (lactose particles were available the more agglomerates of budesonide and lactose were delivered to Stage 2. These results suggest drug-fines agglomerate formation is an important mechanism for how lactose fines improve and regulate DPI formulation performance.

  3. 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

    2016-08-01

    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.

  4. Synthesis of ZnO quantum dots and their agglomeration mechanisms along with emission spectra based on ageing time and temperature

    Science.gov (United States)

    Qiao, Bo; Zhao, Suling; Xu, Zheng; Xu, Xurong

    2016-09-01

    The ZnO quantum dots (QDs) were synthesized with improved chemical solution method. The size of the ZnO QDs is exceedingly uniform with a diameter of approximately 4.8 nm, which are homogeneously dispersed in ethanol. The optical absorption edge shifts from 370 nm of bulk material to 359 nm of QD materials due to the quantum size effect, while the photoluminescence peak shifts from 375 nm to 387 nm with the increase of the density of ZnO QDs. The stability of ZnO QDs was studied with different dispersion degrees at 0 °C and at room temperature of 25 °C. The agglomeration mechanisms and their relationship with the emission spectra were uncovered for the first time. With the ageing of ZnO QDs, the agglomeration is aggravated and the surface defects increase, which leads to the defect emission. Project supported by the FRFCU (Grant No. 2016JBM066), 863 Program (Grant No. 2013AA032205), the National Natural Science Foundation of China (Grant Nos. 61575019, 51272022, and 11474018), and RFDP (Grant Nos. 20120009130005 and 20130009130001).

  5. 多分散结构团聚体烧结的数值模拟%Numerical Simulation for Sintering of Agglomerates Consisting of Polydisperse Primary Particles

    Institute of Scientific and Technical Information of China (English)

    赵海波; 郑楚光

    2012-01-01

    高温环境下团聚体颗粒的烧结现象决定了颗粒表面积、内部非均匀结构等。现有数值模拟方法中一般认为团聚体由若干尺度相同的一次粒子组成,不符合实验测量结果。该文考虑团聚体内一次粒子的多分散性,建立一次粒子质量平衡和数目平衡关系,描述烧结过程团聚体内一次粒子尺度分布函数的演变。对气相法制备TiO2纳米颗粒的烧结定制过程进行数值模拟,模拟结果与实验结果吻合较好,且考虑团聚体内一次粒子多分散分布的模型结果比考虑团聚体内一次粒子单分散分布的模型结果更精确。所建立的描述团聚体烧结过程的多分散模型可适用于多尺度模拟、颗粒群平衡模拟–Monte Carlo方法、多相流模拟的欧拉–拉氏模型等。%The sintering of agglomerates under high temperature determines their surface area and internal inhomogeneous structure.These available models for numerical simulation of sintering phenomenon generally assume that agglomerate consists of equally-sized primary particles(PP),which conflicts with experimental measurements.In this paper,it was considered primary particles within agglomerates satisfy polydisperse distribution.The population balance equations for the mass and number of primary particles were constructed to obtain the evolution of size distribution of primary particles within agglomerates.The polydisperse PP model was then used to simulate the sintering process that was used to tailor TiO2 nanoparticles from the gas phase.It is found that the agreement between experimental measurements and numerical results is well in general,and the polydisperse PP model has advantage in numerical precision with respect to the monodisperse PP model(that considers monodisperse PP within agglomerates).The polydisperse PP model for agglomerate sintering presented in this paper is capable of applying to multiscale modeling,population balance-Monte Carlo

  6. 国内外生产性服务业空间集聚的研究进展%Research progress of the spatial agglomeration on producer services

    Institute of Scientific and Technical Information of China (English)

    申玉铭; 吴康; 任旺兵

    2009-01-01

    As an important sector in service industry, producer services have become a sig-nificant force to promote the economic growth and reflect the main economic function in China's metropolitan regions since the 1990s. In recent decades, the growth and spatial ag-glomeration of producer services become one of the most important economic phenomena in regions of different scales and the most international metropolises. Based on the review of industrial agglomeration and service industrial location, this paper summarizes the re-On the whole, around regions and metropolitans, many scholars at home and abroad have studied this topic and made much progress. However, there are still some shortcomings in some aspects. Firstly, this study has paid much attention to the spatial patterns, while lit-tle can be found in the published literature about evolution process. Secondly, there have been relatively studies on the impact mechanism of the spatial agglomeration on producer services, thus a law theoretic system has not formed. Thirdly, most of the research meth-ods transform the model that measures manufacturing agglomeration to the producer serv-ices. Besides, its applicability and relevance still need to be further explored. The main study trends and orientations in the future can be summarized as follows: Aiming at the research framework "measurement and identification, patterns and process, factors and mechanisms"; and using integrated approach of qualitative-quantitative and spatial analysis to deepen and improve the geographic research of the spatial agglomeration on producer services.%20世纪90年代以来,作为服务业中重要一支的生产性服务业正成为推动我国大城市经济增长的重要力量和体现城市经济职能的主要方面.本文在对产业集聚和服务业区位等相关理论回顾的基础上,对目前周内外生产性服务业空间集聚的主要研究内容和研究方法进行了详尽梳理.总体来看,围绕着区域和大都

  7. 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

  8. 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。

  9. 城市群内城市产业辐射效应测算%Quantifying the Radiation Effect of Industry in Urban Agglomerations

    Institute of Scientific and Technical Information of China (English)

    李俊玮; 常远; 高菠阳

    2015-01-01

    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。%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.

  10. Research on the Association Network of Urban Agglomeration Based on Highway Traffic Flow---Taking Beij ing-Tianj in-Hebei Urban Agglomeration as an Example%基于公路交通流的城市群关联网络研究--以京津冀城市群为例

    Institute of Scientific and Technical Information of China (English)

    傅毅明; 赵彦云

    2016-01-01

    This study constructed an analysis method of urban agglomeration association network based on large data of highway traffic flow,applied it to analyze Beijing-Tianjin-Hebei urban agglomeration, and provided policy recommendations for the coordinated development of Beijing-Tianjin-Hebei areas. By empirical analysis,based on Hebei Province highway toll data,the paper established an OD matrix in middle and south of Hebei urban agglomeration,and by combining with the urban GDP,population and geographical location and other factors,the paper did the statistical analysis on the city level and charges station level of traffic flow distribution to reveal the traffic flow characteristics in middle and south of Hebei urban agglomeration and Beijing-Tianjin and the surrounding areas;further,by using the gravity model to simulate the traffic flow of urban agglomeration,the application of the large data of traffic flow in the urban agglomeration association network is deepened.The results showed that the distribution of traffic flow in Mid-southern Hebei region is differentiation between internal travel which is near and external travel which is border crossing.The association network of Mid-southern Hebei re-gion is weak,the degree of integration is root high,the influence range of shij iazhuang is limited,and the core and connection of the network should be strengthened.Finally,the suggestions on accelerating the construction of Beijing-Tianjin-Hebei traffic big data platform were given for exploring the big data open sharing and economic operation monitoring and early warning and other national big data strate-gies.%构建了基于公路交通流大数据的城市群关联网络分析方法,并应用于京津冀城市群分析,为京津冀协同发展提供政策建议。实证分析上,基于河北地区公路收费数据建立了冀中南城市群 OD矩阵,并结合城市 GDP、人口和地理位置等因素,对城市层面和收费站层面的交通流分布进

  11. Investigation of the agglomeration and amorphous transformation effects of neutron irradiation on the nanocrystalline silicon carbide (3C-SiC) using TEM and SEM methods

    Science.gov (United States)

    Huseynov, Elchin M.

    2017-04-01

    Nanocrystalline 3C-SiC particles irradiated by neutron flux during 20 h in TRIGA Mark II light water pool type research reactor. Silicon carbide nanoparticles were analyzed by Scanning Electron Microscope (SEM) and Transmission Electron Microscopy (TEM) devices before and after neutron irradiation. The agglomeration of nanoparticles was studied comparatively before and after neutron irradiation. After neutron irradiation the amorphous layer surrounding the nanoparticles was analyzed in TEM device. Neutron irradiation defects in the 3C-SiC nanoparticles and other effects investigated by TEM device. The effect of irradiation on the crystal structure of the nanomaterial was studied by selected area electron diffraction (SAED) and electron diffraction patterns (EDP) analysis.

  12. 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.

  13. 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.

  14. 碳酸钙-氯化铵烧结法测定真空炼锂炉渣中锂的含量%Determination of Lithium in Slag Refined by Vacuum with Calcium Carbonate and Ammonium Chloride Agglomeration

    Institute of Scientific and Technical Information of China (English)

    李秋霞; 杨猛

    2001-01-01

    研究了利用碳酸钙-氯化铵烧结法测定金属锂真空精炼后炉渣中锂的含量。%Determination of lithium in slag refined by vacuum with calciumcarbonate and ammonium chloride agglomeration was reported.

  15. 广州会展企业空间集聚特征与影响因素%The agglomeration characteristics and influencing factors of exhibition enterprises in Guangzhou

    Institute of Scientific and Technical Information of China (English)

    方忠权

    2013-01-01

    Exhibition industry is one of the important parts of modern service industry. In recent years, it is developing rapidly and the agglomeration trend in some particular areas of the main center cities is very obvious in China. Based on the data of Guangzhou exhibition enterprises and GIS technology, and using spatial point pattern analysis and questionnaires, this paper discusses the agglomeration characteristics and influencing factors of Guangzhou exhibition enterprises during 1991-2001. Research shows that: (1) Guangzhou exhibition enterprises are significantly agglomerated, and the spatial pattern has been changed from single-center to multi-center agglomeration; (2) Concentration and diffusion coexist. Agglomeration degree of Guangzhou exhibition enterprises does not decrease due to expansion of spatial scale. On the contrary, it diffuses to a new area while constantly strengthening the agglomeration in old areas; (3) Agglomeration areas of exhibition enterprises are divided into two agglomerate types, namely venues-relying type and CBD-relying type, both of which vary in scale and strength of agglomeration; (4) The influencing factors of exhibition enterprises agglomeration include five aspects: exhibition service facilities, overall business environment, external economies, government action and human resources. On the aspect of concrete factors, large exhibition hall and traffic conditions significantly influence the location of exhibition enterprises. But qualified labor force, policy and financial support of the local government, land price and rent have relatively less influence.%会展业是现代服务业重要内容之一,近年来在中国得到快速发展,主要中心城市特定区域的集聚态势十分明显.以广州市会展企业名录为数据基础,借助GIS技术,运用空间点格局分析及问卷调查等方法,探讨了1991-2001年间广州市会展企业的空间集聚特征及影响因素.研究发现,①广州会展企业具有明

  16. 开放式创新背景下产业集聚与创新绩效关系研究——以中国高技术产业为例%Industrial agglomeration and innovation performance under the background of open innovation: evidence from chinese high-tech industries

    Institute of Scientific and Technical Information of China (English)

    陈劲; 梁靓; 吴航

    2013-01-01

    Industrial agglomeration plays a critical role on the innovation of high - tech industries. Under the background of open innovation, this paper studies 221 samples of the high -tech industries in China and examines the relationship between industrial agglomeration and innovation performance based on the theory of agglomeration economies, resource - based view and institutional theory. The results show that the impact of industrial agglomeration on innovation is dependent on the degree of agglomeration. In lower degree, specialization agglomeration is positive to innovation and diversification agglomeration restrains innovation; while in higher degree, specialization agglomeration is negative to innovation and diversification agglomeration promotes innovation. In addition, open innovation can effectively improve the impact of diversification agglomeration on industrial innovation.%产业集聚对高技术产业创新具有重要影响.本文在开放式创新的背景下,整合集聚经济理论、资源观理论和制度理论三种理论视角,以中国高技术产业为研究对象选取了221个样本,对产业集聚程度和创新的关系进行了探索.研究发现,在不同的集聚程度下,产业集聚对创新的影响存在区别:集聚程度较低时,专业化集聚有利于创新,而多样化集聚抑制创新;相反,集聚程度较高时,专业化集聚不利于创新,而多样化集聚促进创新.此外,企业开放式的创新战略能够有效提高多样化集聚对创新绩效的影响.

  17. 室温合成团聚AuPd纳米粒子及其电催化性质%Room Temperature Synthesis and Characterization of Agglomerates of AuPd Bimetallic Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    冯苍松; 梁新义; 崔兰

    2011-01-01

    室温下以水合肼为还原剂,在N,N-二甲基甲酰胺中合成了团聚态的AuPd双金属纳米粒子.X射线衍射(XRD)表征结果证明,所合成的AuPd纳米粒子具有面心立方结构.高分辨透射电子显微镜表征表明,AuPd纳米粒子表面存在大量孪晶结构和晶面层错等表面缺陷.活性评价结果表明,具有高密度晶面缺陷的双团聚态AuPd纳米粒子对甲醇氧化表现出较好的催化活性.%A facile synthesis of the agglomerates of AuPd bimetallic nanoparticles with hydrazine hydrate as a reductant is presented. The structures and morphologies of the agglomerates of AuPd bimetallic nanoparticles were investigated by high-resolution transmission electron microscopy(HRTEM) and X-ray diffraction(XRD). The composition and catalytic property of the AuPd bimetallic nanoparticles were studied by energy dispersive X-ray spectroscopy (EDS) and cyclic voltammetry(CV). The as-synthesized AuPd nanoparticles display agglomerates with face central cubic(fcc) structure enclosed by flat {100} and {111} facets. The details of HRTEM image reveal that unstable small nanoparticles aggregate into the agglomerates of structures. And the surface structure of nanoparticles yields various types of surface defects. Meanwhile, the agglomerates of structure and high density surface defects of AuPd bimetallic nanoparticle are found to dramatically improve the electrocatalytic activities.

  18. 改革开放以来上海服务业集聚的实证研究%Empirical Research on the Agglomeration of Service Sector in ShangHai since Open & Reform

    Institute of Scientific and Technical Information of China (English)

    陈凯; 吴丽

    2012-01-01

    The service sector in ShangHai has kept developing at a relatively high speed since open& reform. But at the same time, we can see that the agglomeration degree of service sector in ShangHai has dropped in contrast to that of China. This article does some empirical research on the factors that have effect on the agglomeration of service sector in ShangHai. The results of empirical analysis are as follows : The income level per capita and the urbanization level have positive effect on the agglomeration degree of service sector in ShangHai, the government scale have negative effect on the agglomeration degree of service sector in ShangHai. The condition of human resources and the information level have unconspicuous effect on the agglomeration degree of service sector in ShangHai.%改革开放以来上海服务业保持了较快的增长速度。但与此同时,其相对于全国的服务业集聚水平却有所下降。本文对影响上海服务业集聚的相关因素进行了实证分析。结果表明:人均收入水平、城市化水平的提高对上海服务业集聚水平有着较强的带动作用;而政府规模的扩大对上海服务业集聚水平则有着负面影响。此外,信息化水平、人力资源状况对上海服务业集聚水平的影响作用不明显。

  19. Marketization Process, Financial Industry Agglomeration and Regional Economic Growth%金融产业集聚、市场化进程与地区经济增长

    Institute of Scientific and Technical Information of China (English)

    纪玉俊; 周素娟

    2015-01-01

    As an important industry in national economy , the financial industry agglomeration can promote regional economic growth , and the realization of the growth effect is related to regional marketization process .Empirically test about the effect of China's financial industry agglomeration on provincial economic growth shows that financial industry agglomeration has promoting effect on the regional economic growth , using data from 1992 to 2011;adding the marketization process to construct threshold regression model to analyze shows that marketization process influ -ences the extent of financial industry agglomeration's growth effect on regional economic , that is to say , a higher level of marketization can better promote the effect of financial industry agglomeration on regional economic growth .%作为国民经济中的重要产业,金融产业集聚可以促进地区经济增长,而这一增长效应的实现与地区市场化进程有关。实证检验我国1992年—2011年各省市金融产业集聚的区域经济增长效应发现,金融产业集聚对区域经济增长具有促进效应;通过加入市场化进程构建门槛回归模型进行分析得出,市场化进程影响金融产业集聚的区域经济增长效应发挥程度,较高的市场化水平可以更好的促进金融产业集聚对区域经济增长效应的发挥。

  20. 天山北坡城市群空间组织形态的识别研究%Identification of spatial organization and spatial morphology of urban agglomeration in North Slope of Tianshan Mountains

    Institute of Scientific and Technical Information of China (English)

    季珏; 高晓路

    2012-01-01

    正确认识天山北坡城市群的空间组织结构以及空间发展形态,对于完善绿洲城市群的发展理论和规划具有重要意义.以天山北坡城市群为研究对象,通过资源环境承载力的分析,总结出未来城市群发展面临的客观制约因素;通过中心性分析、断裂点理论修正的Voronoi多边形等方法识别出城市群的中心城市及各自的辐射范围城市;通过引力模型识别出城市之间的社会经济联系强度.据此,利用多维尺度分析的方法,可视化地展现了天山北坡城市群发展的空间组织形态.经调查了解:(1)乌鲁木齐市与克拉玛依市是未来城市群发展的两个中心城市,五家渠市、阜康市、昌吉市、石河子市周边目前属于乌鲁木齐市的辐射范围城市,奎屯市,乌苏市属于克拉玛依市的辐射范围城市;(2)城市群内部的城市之间的联系比较松散,特别是两个中心城市之间联系较弱;(3)城市群的空间发展形态为串珠式,是一种特殊的走廊式空间形态.%Oasis urban agglomerations have distinctive spatial organizations and morphology with other urban agglomerations as their special landforms and environmental restricts. So how to understand the particularity of oasis urban agglomeration development, and then put forward the suitable development suggestions is an important issue. This paper takes urban agglomeration on the north slope of the Tianshan Mountains as an example, aiming to identify the particular development mode of this representative arid urban agglomeration. Many statistical models and methods were used to interpret the spatial organizations. To be mentioned, visualization of urban agglomeration's spatial morphology was innovatively made in this paper. There are three steps to identify the spatial organization of the urban agglomerations. First, central cities in this region should be picked up. Here, centricity analysis method was used to identify central

  1. Ion-exchange and hydrophobic interactions affecting selectivity for neutral and charged solutes on three structurally similar agglomerated ion-exchange and mixed-mode stationary phases.

    Science.gov (United States)

    Kazarian, Artaches A; Taylor, Mark R; Haddad, Paul R; Nesterenko, Pavel N; Paull, Brett

    2013-11-25

    The nature and extent of mixed-mode retention mechanisms evident for three structurally related, agglomerated, particle-based stationary phases were evaluated. These three agglomerated phases were Thermo Fisher ScientificIon PacAS11-HC - strong anion exchange, Thermo Fisher Scientific IonPac CS10--strong cation-exchange PS-DVB, and the Thermo Fisher Scientific Acclaim Trinity P1silica-based substrate, which is commercially marketed as a mixed-mode stationary phase. All studied phases can exhibit zwitterionic and hydrophobic properties, which contribute to the retention of charged organic analytes. A systematic approach was devised to investigate the relative ion-exchange capacities and hydrophobicities for each of the three phases, together with the effect of eluent pH upon selectivity, using a specifically selected range of anionic, cationic and neutral aromatic compounds. Investigation of the strong anion-exchange column and the Trinity P1 mixed-mode substrate, in relation to ion-exchange capacity and pH effects, demonstrated similar retention behaviour for both the anionic and ampholytic solutes, as expected from the structurally related phases. Further evaluation revealed that the ion-exchange selectivity of the mixed-mode phase exhibited properties similar to that of the strong anion-exchange column, with secondary cation-exchange selectivity, albeit with medium to high anion-exchange and cation-exchange capacities, allowing selective retention for each of the anionic, cationic and ampholytic solutes. Observed mixed-mode retention upon the examined phases was found to be a sum of anion- and cation-exchange interactions, secondary ion-exchange and hydrophobic interactions, with possible additional hydrogen bonding. Hydrophobic evaluation of the three phases revealed logP values of 0.38-0.48, suggesting low to medium hydrophobicity. These stationary phases were also benchmarked against traditional reversed-phase substrates namely, octadecylsilica YMC-Pac Pro C18

  2. 世界级城市群发展特征与规划动向探析%Development Features and Planning Trends of World-class UrbanAgglomeration

    Institute of Scientific and Technical Information of China (English)

    杨建军; 蒋迪刚; 饶传坤; 郑碧云

    2014-01-01

    World-class urban agglomeration, the basic spatial unit in participating in global competition in the new century, is facing many new chal enges, and wil also usher in a new development opportunity. The study summarizes the core features of World-class urban agglomeration from the functional system and organizational system at first, and then analyzes the new technological revolution and its impact, proposing “mega-city region” to be as a new space unit of World-class urban agglomeration planning , exploring the spatial organization mode of World-class urban agglomeration under rail-guided ,finally puts forward the planning strategies and ideas of World-class urban agglomeration in industrial optimization, infrastructure construction and ecological landscape protection in “large-scale”, in order to provide a reference for the development and planning of World-class urban agglomeration at home and abroad.%城市群作为区域一体化发展的载体和参与全球竞争的空间单元,将在新世纪发挥更为重要的作用,特别是世界上顶级的城市群将主导经济社会的发展趋势。文章以世界级城市群面临的发展机遇和挑战为背景,从功能体系和组织体系两方面总结了世界级城市群的核心特征,在分析新技术革命及其影响的基础上,提出“巨型城市区域”将作为世界级城市群规划的新空间单元;探讨轨道交通引导下的世界级城市群空间组织模式;并从世界级城市群的规划层面,探索产业转型优化、基础设施建设、生态景观保护的“大型化”等三方面策略,以期为国内世界级城市群的发展与规划提供借鉴。

  3. An Empirical Analysis of Cost Effect about the Regional Industrial Agglomeration:A Perspective Based on Provincial Food Manufacturing in China%区域产业集聚成本效应的实证分析--中国省际食品制造业视角

    Institute of Scientific and Technical Information of China (English)

    贺旭辉; 田国英

    2014-01-01

    One main function of industrial agglomeration is cost saving .By choosing food manufacturing of thirty regions in our country as research objects , the paper empirically analyses the cost effect of regional industrial ag-glomeration.Firstly, the regional agglomeration of food manufacturing reveals cost saving effect on the whole , but such effect of different regions is different .Secondly , the cost effect of food manufacturing ’ s regional industrial ag-glomeration is not only closely related to the degree of agglomeration , but to the change of agglomeration .In the re-gions such as high agglomeration and agglomeration rising of food manufacturing , the cost saving is obviously , but the regions such as low agglomeration and agglomeration declining of food manufacturing , the cost reveals rising.%产业集聚的一大功能在于节约成本。以食品制造业为对象,实证考察了区域产业集聚的成本效应,结果发现:食品制造业的区域集聚总体上产生了成本节约效应,但不同地区存在一定的差异;食品制造业区域集聚的成本效应不仅与集聚度高低密切相关,而且与集聚度的变化有一定的关系。高集聚和集聚成长地区食品制造业集聚的成本节约效应较为明显,而低集聚和集聚衰退地区食品制造业的集聚则出现成本上升现象。

  4. Friction Stir Welding of Al Alloy 2219-T8: Part I-Evolution of Precipitates and Formation of Abnormal Al2Cu Agglomerates

    Science.gov (United States)

    Kang, Ju; Feng, Zhi-Cao; Frankel, G. S.; Huang, I. Wen; Wang, Guo-Qing; Wu, Ai-Ping

    2016-09-01

    Friction stir welding was performed on AA2219-T8 plates with 6.31 wt pct Cu. The thermal cycles were measured in different regions of the joint during welding. Differential scanning calorimetry and transmission electron microscopy were utilized to analyze the evolution of precipitates in the joint. The relationships between welding peak temperature, precipitate evolution, and microhardness distribution are discussed. The temperature in the heat-affected zone (HAZ) ranged from 453 K to 653 K (180 °C to 380 °C). The θ″ and some θ' phases redissolved into the HAZ matrix, while the rest of the θ' phases coarsened. In the thermomechanically affected zone (TMAZ), the temperature range was from 653 K to 673 K (380 °C to 400 °C), causing both θ″ phase and θ' phase to redissolve. In the weld nugget zone (WNZ), all the θ″, θ', and some of the θ phase (Al2Cu) redissolved. Abnormal θ particles were observed in the WNZ, including agglomerated θ with sizes around 100 to 1000 µm and a ring-shaped distribution of normal size θ particles. The formation of abnormal θ particles resulted from metal plastic flow during welding and the high content of Cu in AA2219. No abnormal θ particles were observed in joints of another AA2219 plate, which had a lower Cu content of 5.83 wt pct.

  5. Impact of anthropogenic aerosols on summer precipitation in the Beijing-Tianjin-Hebei urban agglomeration in China: Regional climate modeling using WRF-Chem

    Science.gov (United States)

    Wang, Jun; Feng, Jinming; Wu, Qizhong; Yan, Zhongwei

    2016-06-01

    The WRF model with chemistry (WRF-Chem) was employed to simulate the impacts of anthropogenic aerosols on summer precipitation over the Beijing-Tianjin-Hebei urban agglomeration in China. With the aid of a high-resolution gridded inventory of anthropogenic emissions of trace gases and aerosols, we conducted relatively long-term regional simulations, considering direct, semi-direct and indirect effects of the aerosols. Comparing the results of sensitivity experiments with and without emissions, it was found that anthropogenic aerosols tended to enhance summer precipitation over the metropolitan areas. Domain-averaged rainfall was increased throughout the day, except for the time around noon. Aerosols shifted the precipitation probability distribution from light or moderate to extreme rain. Further analysis showed that the anthropogenic aerosol radiative forcing had a cooling effect at the land surface, but a warming effect in the atmosphere. However, enhanced convective strength and updrafts accompanied by water vapor increases and cyclone-like wind shear anomalies were found in the urban areas. These responses may originate from cloud microphysical effects of aerosols on convection, which were identified as the primary cause for the summer rainfall enhancement.

  6. Control of the size, shape and composition of highly uniform, non-agglomerated, sub-micrometer β-tricalcium phosphate and dicalcium phosphate platelets.

    Science.gov (United States)

    Galea, Laetitia; Bohner, Marc; Thuering, Juerg; Doebelin, Nicola; Aneziris, Christos G; Graule, Thomas

    2013-09-01

    Calcium phosphates (CaPs) are widely used as bone graft substitutes but are inherently brittle, hence restricting their use to mechanically protected environments. Combining them with a tough polymer matrix could potentially lead to a composite with load-bearing properties. However, the highest mechanical properties can only be achieved if the CaP particles possess very precise features: they should be uniform in size and shape, non-agglomerated, elongated and thin. The aim of the present study therefore was to assess a novel method to produce such particles. This involved the precipitation of CaP particles in ethylene glycol at moderate temperatures (90-170 °C) and the variation of different reaction parameters (temperature, concentration, pH, etc) to study their influence on particle composition, size, shape and dispersion was studied. As a result, two main CaP phases were obtained as well-dispersed and highly uniform platelets in the form of: (i) β-tricalcium phosphate (β-TCP) hexagonal prisms and (ii) monetite (DCP) flat parallelepipeds. The size dispersion was the narrowest for β-TCP (standard deviation/mean < 5%) whereas the aspect ratio was the highest for DCP (up to 25). In both cases, the thickness of the platelets was below 300 nm which should be ideal for the synthesis of strong CaP-based composites.

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

    Science.gov (United States)

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

    2014-08-01

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

  8. Effects of urban agglomeration on surface-UV doses: a comparison of Brewer measurements in Warsaw and Belsk, Poland, for the period 2013-2015

    Science.gov (United States)

    Czerwińska, Agnieszka E.; Krzyścin, Janusz W.; Jarosławski, Janusz; Posyniak, Michał

    2016-11-01

    Specific aerosols and cloud properties over large urban regions seem to generate an island, similar to the well-known urban heat island, leading to lower ultraviolet (UV) radiation intensity compared to the surrounding less polluted areas, thus creating a shield against excessive human exposure to UV radiation. The present study focuses on differences between erythemal and UVA (324 nm) doses measured by the Brewer spectrophotometers in Warsaw (52.3° N, 21.0° E) and Belsk (51.8° N, 20.8° E). The latter is a rural region located about 60 km south-west of the city. Ratios between erythemal and UVA partly daily doses, obtained during all-sky and cloudless-sky conditions for the period May 2013-December 2015, were analysed to infer a specific cloud and aerosol forcing on the surface UV doses over Warsaw. Radiative model simulations were carried out to find sources of the observed differences between the sites. It was found that Warsaw urban agglomeration induced 8 and 6 % attenuation of the erythemal and UVA doses respectively. This is mostly due to the lower sun elevation in Warsaw during the near-noon measurements and the larger optical depth of the city aerosols and increased cloudiness. It could be hypothesised that the expected stronger absorption of the solar UV radiation by urban aerosols is compensated for here by a higher surface reflectivity over the city.

  9. The Impact of Land Cover Change on Ecosystem Service Values in Urban Agglomerations along the Coast of the Bohai Rim, China

    Directory of Open Access Journals (Sweden)

    Yushuo Zhang

    2015-08-01

    Full Text Available Local ecosystem services have been significantly affected by land cover changes associated with rapid urbanization in China. Based on the 2000 and 2010 land cover data products with 30-m resolution, we examined the similarities and differences in the impacts of land cover change on ecosystem service values (ESV at three coastal urban agglomerations in China between 2000 and 2010 (Liaodong Peninsula (LP, Jing-Jin-Ji (JJJ and Shandong Peninsula (SP. A rapid evaluation method developed by Xie et al. (2008 was used to derive an ecosystem service value coefficient. The most significant change was an increase in artificial surfaces, due to urban expansion, which mainly occurred on cultivated land. The greatest loss in total ESV (2273 million Chinese Yuan occurred in SP, due to the large decrease in wetland areas, because this service has the highest estimated coefficient. The second greatest loss in ESV (893 million Yuan occurred in JJJ, due to the urban expansion of major cities. In contrast, ESV increased (72 million Yuan in LP. This study demonstrates that urban expansion does not necessarily lead to a net decline in ESV. In conclusion, land use and land cover policymaking should consider the sustainability of ecosystem services in relation to economic growth.

  10. A laboratory measurement method for pressure sensitive adhesives in agglomeration deinking of mixed office waste paper: The high-low scanning contrast method

    Directory of Open Access Journals (Sweden)

    Guolin Tong

    2012-11-01

    Full Text Available A simple measurement method for pressure sensitive adhesives (PSA in an agglomeration deinking system of mixed office waste paper was studied. This method was based on the different scanning performance of ink and PSA specks in hot-pressed and oven-dried handsheets with the change of contrast values that had been selected and set in the image analysis software. The numbers of ink specks per square meter (NPM were well recognized at both low and high contrast values and exhibited a very good linear relationship within a range of contrast values. The PSA specks, on the other hand, could not be recognized at the low contrast values and could only be recognized at high contrast values. The NPM value of the ink specks was found to have the highest values at the high contrast values and could be accurately predicted by its NPM value at the low contrast values. Thus, the NPM value of the PSA specks could be easily calculated by the total NPM of the handsheet at the high contrast value minus the projected NPM of the ink specks from its low contrast conditions. Compared to the dye method, which was also used on the measurement of microstickies, this method is suggested as a simple and quick laboratory tool to measure the relative quantity of PSA in the mixed office waste paper with minimum interference from the residual toner ink.

  11. Avaliação da influência dos processos de lecitinação e de aglomeração nas propriedades físicas de achocolatado em pó Evaluation of the influence of lecithination and agglomeration on the physical properties of a cocoa powder beverage (cocoa powder beverage lecithination and agglomeration

    Directory of Open Access Journals (Sweden)

    Fernanda Zaratini Vissotto

    2006-09-01

    Full Text Available O objetivo deste trabalho é comparar a solubilidade, a molhabilidade e a distribuição granulométrica de achocolatado em pó, submetido aos processos de: simples mistura; mistura e lecitinação (0,3; 0,5; 0,8 e 1% de lecitina de soja; e mistura, lecitinação (0,3; 0,5; 0,8 e 1% de lecitina e aglomeração. Ao comparar o produto obtido pelo processo de simples mistura com o lecitinado, constata-se que a presença da lecitina melhora a solubilidade do produto em todos os tratamentos utilizados. O processo de aglomeração, após a lecitinação, incrementa ainda mais a solubilidade do produto, determinada neste trabalho pelo índice de retenção - IR. Comparando-se o IR dos tratamentos estudados, foram obtidos os resultados: IRmistura = 2,65%; IR0,3%lec. = 2,07%; e IR0,3%lec.aglom. = 0,79%. Quanto à molhabilidade, observa-se que os produtos lecitinados apresentaram menores tempos em relação aos submetidos a simples mistura, e o processo de aglomeração proporcionou uma diminuição ainda maior destes tempos (t mistura = 8 min 16 s; t0,3%lec. = 4 min 33 s; t0,3%lec.aglom. = 3 min. Não se observou influência do processo de lecitinação sobre a distribuição granulométrica da bebida em pó. Já o processo de aglomeração ocasionou modificação significativa nesta propriedade.The aim of this article is to compare the solubility, wettability and granulometric distribution of a cocoa powder beverage, which went through the following process: simple blending; blending and lecithination (0.3; 0.5; 0.8 and 1.0% of soy lecithin and blending, lecithination (0.3; 0.5; 0.8 and 1.0% of soy lecithin and agglomeration. Comparing the product obtained with the simple blending process and the lecithinated product, the conclusion is that the presence of lecithin improves the powder beverage solubility in all the conditions used. The agglomeration process, after lecithination, improves the solubility of the product, which was determined in this

  12. The Coordinated Development of Wuguiyu Urban Agglomeration in Guangxi-- Based on SWOT Analysis%广西梧玉贵城市群协调发展探讨--基于SWOT分析

    Institute of Scientific and Technical Information of China (English)

    覃耀坚

    2015-01-01

    With increasingly frequent communication with ASEAN countries and the construction of the Silk Road Economic Belt, Guangxi’s strategic position is getting more outstanding. In recent years, urban agglomeration has become the basic form of spatial organization of regional economic development. Urban agglomeration is strategic points for both the development space of territorial resources and the development of main functional areas. This core economic development area is of the most dynamic and potential. It is also the nation’s main form of urban development in the future. In 2008, Guangxi officially launched urban agglomeration construction plan, the gulf-type urban agglomeration, or Nanbeiqinfang urban agglomeration, is the first batch regional urban agglomeration of Guangxi, which has made an important contribution to promote the local economic and social development. Building the Wuguiyu urban agglomeration will play an irreplaceable role in optimizing the layout of the regional integration and spur the economic growth. This paper, by the method of SWOT analysis, dissects Wuguiyu urban agglomeration and provides it with coordinated development path selections.%随着与东盟国家的交流日益频繁和丝绸之路经济带的建设,广西在国家经济建设中的战略地位越来越突出。近年来,伴随着中国城镇化进程的加快,城市群逐渐成为区域经济发展空间组织的基本形式。城市群是我国国土资源空间和主体功能区重点开发的战略支撑点,是经济发展最具活力与潜力的核心地区,也是未来我国城市发展的主要形态。2008年,广西正式启动城市群规划建设,“中国-东盟自由贸易区的海湾型城市群”即南北钦防城市群是广西建设的首批区域性城市群,对促进广西经济社会发展,提升广西整体竞争实力作出了重要的贡献。构建广西梧玉贵城市群,对优化区域一体化布局,拉动新一极经济

  13. Preparation and characterization of nano fluids: Influence of variables on its stability, agglomeration state and physical properties; Preparacion y caracterizacion de nanofluidos: Influencia de variables sobre su estabilidad, estado de aglomeracion y propiedades fisicas

    Energy Technology Data Exchange (ETDEWEB)

    Mondragon, R.; Julia, J. E.; Barba, A.; Jarque, J. C.

    2014-10-01

    In recent years it has spread the use of suspensions containing nano metre sized particles, known as nano fluids, in many applications owing the good properties having nanocrystalline materials. One of the main advantages of using nano fluids is its high stability, which causes the particles do not settle over long periods of time. This stability depends on the preparation conditions such as pH, the presence of electrolytes or the solids content. Moreover, there are a number of physical properties which are influenced and altered by agglomeration of the particles. This article will analyze all the variables that affect agglomeration of the particles, nano fluids stability and properties from which it can obtain information on the state of suspension. It then lays out the different methods of dispersion of nanoparticles and their effectiveness. (Author)

  14. 化学团聚促进电除尘脱除PM2.5的实验研究%Improving removal of PM2.5 by electrostatic precipitator with chemical agglomeration

    Institute of Scientific and Technical Information of China (English)

    刘勇; 赵汶; 刘瑞; 杨林军

    2014-01-01

    Emission of fine particles from coal combustion is an important source of atmospheric PM2.5. The removal of PM2.5 from coal combustion by electrostatic precipitator (ESP) with adding agglomerant solution and evaporating treatment of desulfurized wastewater was investigated experimentally based on the coal-fired thermal system. Change of concentration and diameter distribution of particles were tested before and after agglomeration, and the influence factors, including concentration of agglomerant solutions, temperature of flue gas at the point of addition,agglomeration solution pH,flue gas flow, and diameter of spray droplets were analyzed. The average diameter of particles could grow more than four times with the effect of wetting, liquid bridge force and adsorption bridging, and the PM2.5 concentration at ESP outlet could decrease by more than 40%under typical flue gas conditions. Increasing concentration of agglomeration solution could promote PM2.5 removal. Reducing agglomeration solution pH was better for agglomeration by making the polymer chain more soft stretch. The PM2.5 concentration at ESP outlet had no change after spraying desulfurized wastewater, and the PM2.5 concentration decreased when adding agglomeration solution.%燃煤排放细颗粒物是大气环境 PM2.5增加的重要来源。采用燃煤热态实验系统,进行了在电除尘器入口烟气添加化学团聚剂以及协同脱硫废水蒸发处理促进电除尘脱除 PM2.5的实验研究。实验考察了团聚剂添加前后PM2.5浓度及其粒度分布的变化,以及团聚剂浓度、添加点烟温、团聚剂溶液 pH、烟气量、雾滴粒径等对 PM2.5脱除效果的影响。结果表明,添加化学团聚液后,通过润湿作用、液桥力和吸附架桥作用可增强 PM2.5之间的接触并促进团聚长大,PM2.5增大到原先的4倍左右,典型工况下电除尘器出口PM2.5浓度降低40%以上。增加团聚液浓度可促进PM2.5的脱除;适当

  15. 针对B2C电商自营物流的城市群分布模型%Distribution model of urban agglomeration for B2 C e-commerce self-logistics

    Institute of Scientific and Technical Information of China (English)

    李晓文; 王东

    2015-01-01

    In the perspective of urban agglomerations, cities are no longer as isolated indi-viduals, but attracted together for the order demand.By designing the model, urban agglom-eration gravity of the whole country is maximized.By selecting the calculated range of urban agglomerations as self-logistics area, the center in the gravity center was built to service the urban agglomeration, the input-output ratio of investment was optimized to cover the highest user needs within minimum area and realize economies of scale for logistics services.It can reduce logistics costs, while improving the level of logistics services in the most densely area of consumer distribution.%从城市群的角度出发,各城市不再作为孤立的个体,而因为订单需求而“吸引”在一起。通过设计模型,使得全国范围内所有城市群订单引力之和最大。选取计算出的城市群为自营物流范围,以城市群引力中心分别建设城市群仓储配送中心,服务所在城市群。优化了物流投入产出比例,以最小面积的投入来覆盖最高的用户需求,实现了自营物流服务的规模效应,降低了物流成本的同时,在消费者分布最密集区域全方位提升了物流服务水平。

  16. Analysis on Turning to Public Policy of Pearl River Delta Urban Agglomeration Planning%珠江三角洲城市密集区规划的公共政策转向分析

    Institute of Scientific and Technical Information of China (English)

    贾莉

    2016-01-01

    在全球化时代,城市密集区规划成为提升区域竞争力的一种重要措施。城市密集区规划逐渐从传统的技术工具模式向公共政策的转向。珠三角城市密集区规划的发展的回顾,可反映出这种转向,并体现出中国特色。但严格从公共政策视角分析,珠三角城市密集区规划无论在政策价值导向、政策行动主体以及政策执行过程都存在一些不足,有待社会环境的改善而得到优化。本文相应提出了提升城镇密集区规划的公共政策性的可行性路径。%With globalization, urban agglomeration planning has become an important measure to improve regional competitiveness. It gradually transforms traditional technical tool into public policy. The development of agglomeration planning of Pearl River Delta relfects this change and national features. But with a strict analysis from the view of public policy, urban agglomeration planning has some shortage in the policy value orientation, policy operative body and policy implement course. It would be perfected with improvement of social environment. This paper proposes the feasible path of promoting characteristic of public policy urban agglomeration planning.

  17. Water Use Efficiency Improvement against a Backdrop of Expanding City Agglomeration in Developing Countries—A Case Study on Industrial and Agricultural Water Use in the Bohai Bay Region of China

    Directory of Open Access Journals (Sweden)

    Minghao Bai

    2017-02-01

    Full Text Available Most city agglomerations of developing countries face water shortages and pollution due to population growth and industrial aggregation. To meet such water security challenges, policy makers need to evaluate water use efficiency at the regional or basin level because the prosperity of city agglomerations is indispensable to the sustainable development of the region or basin. To solve the issue, this paper adopts a non-directional distance function within the framework of environmental production technology to measure water use efficiency. Based on the distance between actual water use efficiency and the ideal efficiency, it calculates the potential reduction space of water input and pollutants by slack adjustment. Added to the Malmquist index, it forms a non-radial Malmquist water use performance index, which can be divided into technological change and technical efficiency change, to measure dynamic water use efficiency. Further, water use efficiency change is analyzed from the perspectives of technological improvement and institutional construction. Bohai Bay city agglomeration, a typical water-deficient city agglomeration in China, is taken as a case study, and data on water resource, environment, and economy from 2011 to 2014 have been used. In conclusion, there is much space for water use efficiency improvement on the whole. However, even having considered potential reduction space of water input and pollutant discharge under current environmental production technology, it is still not enough to support the city agglomeration’s sustainable development. To relieve current potential water safety hazards, not only technical improvement but also institution innovation for highly efficient water use should be kept accelerating in Bohai Bay region. In terms of urban water management in developing countries, the research conclusion is of theoretical and practical significance.

  18. Empirical Analysis on Agglomeration Level and Influencing Factors of Cultural Industry in Jiangsu Province%江苏省文化产业集聚水平及影响因素实证分析

    Institute of Scientific and Technical Information of China (English)

    肖燕

    2015-01-01

    文化产业作为21世纪的朝阳产业,在大多数发达国家已经得到快速的发展。文化产业具有强关联性的特征,产业的集聚发展能够在最大限度上实现资源的充分利用。江苏省地处我国东部沿海,为发展文化产业集聚提供了丰富的历史、地理、人文方面的资源优势。文章介绍了文化产业集聚的概念,实证分析了江苏省文化产业集聚的发展水平,并从六个方面探究江苏省文化产业集聚的影响因素,进而提出江苏省发展文化产业集聚的对策建议。%As a sunrise industry in the 21st century, the cultural industry has gained rapid development in most developed countries. The cultural industry has the characteristic of strong relevancy with other indus-tries, so the agglomeration development of industry will maximize the efficiency of utilization of the re-source. Jiangsu province is located in Chinese eastern coast, it has provided rich history, geography and humanistic resources advantage for the development of cultural industry. The paper simply intro-duces the concept of cultural industry agglomeration, then analyses the developmental level of cultural industry agglomeration of Jiangsu province, therewith from six aspects explores the influencing factors of cultural industry agglomeration, finally the paper puts forward some suggestions.

  19. ATTENTION TO DEVELOPMENT OF MEGA-URBAN AGGLOMERATIONS DURING 12TH FIVE-YEAR PLAN PERIOD%"十二五"期间需要注重巨型城市群发展问题

    Institute of Scientific and Technical Information of China (English)

    顾朝林

    2011-01-01

    中国城市化正在进入加速发展时期,城市人口和经济均具有向东部沿海进一步集聚的趋势,城市群和巨型城市区应该是"十二五"期间国家未来城市化空间发育的重要形式.根据我国巨型城市化空间现象,建议"十二五"期间注重巨型城市群发展问题.%China is entering a period of accelerated development of urbanization. Urban population and urban economy have the tendency to further gather at the east coast area. This paper argues that urban agglomerations and mega-city areas should be the important spatial forms of China's urbanization development. Based on the space phenomena of China's urban agglomerations,it proposes focusing on the development of megaurban agglomerations during the 12th Five-Year Plan period.

  20. Study on the agglomerate structure in wheat starch retrogradation by SAXS%小麦淀粉回生中凝聚结构变化的SAXS研究

    Institute of Scientific and Technical Information of China (English)

    郭培培; 刘钟栋; 占学旺

    2012-01-01

    采用同步辐射X射线小角散射研究了小麦淀粉回生过程凝聚结构的变化.淀粉凝聚体成多散系特征,在淀粉回生过程中乳化剂的加入有效的抑制了淀粉链的移动,形成了淀粉-乳化剂络合物或超分子结构,在回生后期,乳化剂抑制了淀粉凝胶体之间聚集絮凝和回转半径Rg的增大.乳化剂的加入增大了小麦淀粉凝胶体界面层厚度,从10nm~12nm增加到11 nm~14nm.小麦淀粉中直链淀粉的首先絮凝改变散射体系中两相的分布.淀粉凝聚结构均成质量分形(Dm)特征,在淀粉回生前期,小麦淀粉Dm为2.0,而添加蔗糖酯的小麦淀粉Dm为2.31;糯玉米淀粉Dm为1.67,添加蔗糖酯后,糯玉米回生淀粉液Dm为2.60,表明乳化剂能有效的和淀粉凝聚结构络合,形成稳定的网络结构,增大了小麦淀粉凝聚结构的Dm.%This paper studies on the change of the agglomerate structure in the wheat starch retrogradation by synchronization radiation small Angle X - ray scattering. Starch granules have the characteristic of scattering into many fauna. In starch retrogradation, adding emulsifiers could effectively restrain starch chain moving, and promote the starch -emul-sifier complex or supramolecular structures forming. Emulsifiers could also retrain starch flocculating and Rg of starch increasing in the last retrogradation stage. The addition of emulsifier increased the thickness of interface layer in wheat starch gel, from 10 nm ~ 12nm to llnm ~ 14nm. The amylose flocculation changed two phase' s distribution in wheat starch scattering system. In starch gelatinization - retrogradation, intermediate molecules aggregated into quality process of mass fractal (Dm) features. Wheat starch amylose in the first flocculation changes scattering system of two phase distribution. Starch agglomerate structure is characterized by quality fractal. In the early retrogradation, wheat starch Dm was 2.0, but Dm of wheat starch adding sucrose ester was

  1. 声波团聚中尾流效应的理论研究%Theoretical Study of Acoustic Wake Effect in Acoustic Agglomeration

    Institute of Scientific and Technical Information of China (English)

    张光学; 刘建忠; 王洁; 周俊虎; 岑可法

    2013-01-01

    Acoustic agglomeration is a potential aerosol preconditioning process to reduce particulate matter emission. Recently, acoustic wake effect has been experimentally found to be an important hydrodynamic mechanism in acoustic agglomeration process. This paper presents a numerical simulation of the hydrodynamic interaction of aerosol particles due to acoustic wake effect under Oseen flow condition. The influence of the angle, included between the particle and acoustic field, particle size and acoustic frequency on particle convergence velocity due to acoustic wake effect was investigated. The particle convergence velocity varies greatly as the included angle changes. Strong attraction was found for particles with an included angle of 0° to 50°, and reaches a maximum at 0°. Outside this range, weak repulsion was found and reaches a maximum at 90°. Particle convergence velocity increases with increasing acoustic frequency, but tends to approach a constant value at a threshold frequencies, which increases with the increase of particle sizes. In addition, it was found that with increasing particle size the particle convergence velocity increases proportionally.%  声波团聚是一项非常有潜力的颗粒物排放控制技术,最近的实验表明声波尾流效应是其中的重要机理。研究建立了Oseen条件下声波团聚中的尾流效应理论模型,并采用数值方法进行求解。研究了颗粒夹角、粒径和频率对声波尾流效应下的聚合速度的影响。计算结果表明,颗粒与声场的夹角对聚合速度影响很大,存在吸引和排斥两个区域。当夹角为0°~50°时,颗粒间存在强吸引作用,颗粒与声场平行时,聚合速度达到最大值;当夹角为50°~90°时,颗粒间表现为弱排斥作用,颗粒与声场垂直时,排斥速度最大。聚合速度随频率的增大而增加,但当频率超过某一临界值时,聚合速度基本保持不变;颗粒粒径越大,该临

  2. The Properties of Traffic Networks in Urban Agglomeration%城市群城镇交通网络特性研究

    Institute of Scientific and Technical Information of China (English)

    王国明; 李夏苗; 杨波; 胡正东

    2012-01-01

    In order to research properties of traffic network of urban agglomerations, We design the model of Urban Agglomeration by primal approach to describle the Changsha traffic network, the Zhuzhou traffic network, the Xiangtan traffic network, the C-Z-T city traffic network, the C-Z-T city and town traffic network, the C-Z-T city and town traffic network. We use Matlab and VC+-H6. 0 to figure out averaged-degree, averaged-clustering coefficient, betweenness centrality of roads with degree and structure entropy based on node betweenness centrality, global coefficient. The results show that (1) traffic networks have small-world behavior but no scale-free property (2) traffic networks have not scale-free and random property, (3) the global coefficient of the C-Z-T city traffic network is greatest and the entropy of the C-Z-T city and town traffic network is smallest, which show it is in order.%为了研究城市群城镇交通网络特性,本文运用primal approach方法以城镇为节点,以其之间的道路为边构造长沙城镇交通网络、株洲城镇交通网络等城市群城镇交通网络模型,使用Matlab和VC+ +6.0分别对它们的平均度、网络密度、聚集系数、平均最短路径、随机网络聚集系数、随机网络平均最短路径、网络结构熵、全局系数等网络特性指标进行计算和比较分析,得到以下结论:(1)城市群城镇交通网络都具有小世界性,是小世界网络;(2)城市群城镇交通网络都不存在幂律特征,不存在无标度性,不是无标度网络;(3)城市群城镇交通网络都不存在指数特征,不是随机网络;(4)城市群城镇交通网络中,长株潭城市群市县交通网络整体效率最高、网络密度最大,长株潭城市群城镇交通网结构熵最小,表明其最有序.

  3. The effect of titanium dioxide (TiO2) nano-objects, and their aggregates and agglomerates greater than 100nm (NOAA) on microbes under UV irradiation.

    Science.gov (United States)

    Yamada, Ikuho; Nomura, Kazuki; Iwahashi, Hitoshi; Horie, Masanori

    2016-01-01

    Today, nanoparticles are used in many products. One of the most common nanoparticles is titanium dioxide (TiO2). These particles generate reactive oxygen species (ROS) upon UV irradiation. Although nanoparticles are very useful in many products, there are concerns about their biological and ecological effects when released into the environment. Thus, it was assessed that the effect of TiO2 nano-objects, and their aggregates and agglomerates greater than 100nm (NOAA) on microbes under UV irradiation by using Escherichia coli and Saccharomyces cerevisiae. ROS generation was evaluated by adding TiO2 nanoparticles and methylene blue to distilled water. We also assessed growth inhibition by adding TiO2 nanoparticles and microbes in minimal agar medium. Moreover, microbial inactivation was assessed by adding TiO2 nanoparticles and microbes to PBS. Upon UV irradiation, TiO2-NOAAs decomposed methylene blue and generated ROS. TiO2-NOAAs also decomposed methylene blue in minimal agar medium under UV irradiation; however, they did not inhibit microbial growth. Surprisingly, TiO2-NOAAs in the medium protect microbes from UV irradiation as colony formation was observed only near TiO2-NOAAs. In PBS, TiO2-NOAAs did not inactivate microbes but instead protected microbes from lethal UV irradiation. These results suggest that the amount of ROS generated by TiO2-NOAAs is not enough to inactivate microbes. In fact, our results suggest that TiO2-NOAAs may protect microbes from UV irradiations.

  4. [Preparation of an agglomerated ion chromatographic stationary phase with 2,3-ionene and its application in SO4(2-) analysis].

    Science.gov (United States)

    Wang, Muhua; Liu, Junwei; Huang, Zhongping; Zhang, Jiajie; Zhu, Yan

    2015-07-01

    The poly-electrolyte cation functional group of 2,3-ionene was synthesized with tetramethyl ethylenediamine and 1,3-dibromopropane as the raw materials. Multiporous polystyrene-divinylbenzene microsphere particles (PS-DVB) were produced by swelling method with polystyrene as seeds and sulfonated. Then the 2,3-ionene was bonded on the sulfonated multi-porous polystyrene-divinylbenzene microsphere particles by agglomeration to get the agglomerative ion-exchange stationary phase. After optimizing the synthetic conditions, the new stationary phase was characterized by the techniques including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and elemental analysis. The chromatographic column was packed by slurry method and applied in the analysis of SO4(2-) with a conductivity detector. SO4(2-) and other six common anions including F-, Cl-, NO2(-), Br-, NO3(-), PO4(3-), were separated and analyzed rapidly on the self-regulating chromatographic column within 8 min. The linear range was from 0.5 to 50 mg/L with correlation coefficient (r) of 0.9992. The LOD was 0.04 mg/L with S/N of 3. The relative standard deviations (RSDs, n = 6) were 2.4% and 3.1% for the peak area and retention time, respectively. The recoveries were between 99.2% and 101.8%. The retention times of SO4(2-) did not change significantly after long time use of the self-regulating chromatographic column. The self-regulating chromatographic column is suitable for the detection of SO4(2-) in complex matrix samples.

  5. 基于网络演化方法的城市群城际铁路线网规划模型研究%Network Evolution-based Planning Model for Intercity Railway Network within Urban Agglomeration

    Institute of Scientific and Technical Information of China (English)

    黄超; 刘苏; 吕颖

    2016-01-01

    Intercity railway network plays an important role in the integration of urban agglomeration, and reasonable planning is of great significance on the basis of urban agglomeration spatial structure. This paper, based on network evolution, takes node importance and economic contact intensity as major parameters of network evolution, and a planning model of the intercity railway network of urban agglomeration is constructed, under the comprehensive consideration of social economy of the specific urban agglomeration. With the analysis of technical performance and constraints of the intercity railway network, evolution mechanism and evolution algorithm are present. At last, the Chengdu-Chongqing urban agglomeration is taken as a case to validate the planning model. The result shows that this model is reasonable and efficient, and provides an important guidance on the intercity railway network planning.%城际铁路网络在城市群一体化发展中发挥着重要作用,在城市群空间结构的基础上进行合理规划意义重大。本文基于网络演化思想,将节点重要度和城市经济联系强度指标作为重要参数,在综合考虑城市群社会经济影响的基础上,构建城市群城际铁路线网布局规划模型,并对城际铁路线网的技术性能和约束条件进行分析,提出节点成长、线路连接、边权演化规则,设计网络演化机制和城际铁路网络演化算法。以成渝城市群为对象进行实证分析,得到不同参数组合下的演化结果和城际铁路线网规划方案,验证了模型的合理性和适用性,对实际城市群城际铁路线网规划工作有一定的参考价值。

  6. 中国FDI双重集聚的非线性转换效应——基于LPSTR模型%The Nonlinear Transformation Effects from the Dual Agglomeration of China's FDI Industry:a Study Based on LPSTR Model

    Institute of Scientific and Technical Information of China (English)

    赵果庆

    2015-01-01

    The dual agglomeration of China' s FDI refers to concentration in both spatial and industrial levels. In this respect,how FDI industrial agglomeration boosters structural transformation of domestic industries and how enlarges regional gaps of domestic industries are two questions of important research interest and policy studies. Armed with the model of Non-Linear Panel Smooth Transition Regression ( NLPSTR ) , we estimate the dual agglomeration of FDI industries on the industry growth and structural transformation of domestic industry. The results show that the agglomeration of FDI industry improves the industry structure of domestic industries by generating function transformation and enlarges regional gap of domestic industries at the same time. Thus,China should improve the investment climate in weak regions,and attract FDI' s agglomeration which boosts the institutional transformation of domestic industries in order to narrow the gap of regional development. In this way we prevent the excessive dependence on the technologies of FDI industries by developing innovation and its own core technologies in high mechanism of industries.%中国FDI产业在空间与产业发生双重集聚现象. FDI产业的集聚如何帮助我国内资产业转换结构,又如何扩大地区内资产业发展差距,这是具有学术和政策研究价值的一个问题的两个方面. 本文基于Logistic函数面板平滑转换回归模型( LPSTR)模型,以2003-2011年数据检证了FDI产业的双重集聚溢出对内资产业增长机制及其结构转换效应. 结果表明,FDI产业集聚通过内资产业生产函数转换提升了我国内资产业结构,同时还扩大了地区内资产业发展差距. 因此,我国要改善低机制地区投资环境,吸引FDI产业集聚,以FDI产业集聚促进内资产业增长机制转换,从而缩小我国地区产业极差,同时,还要建立产业创新机制,营造核心技术,以防高机制产业对FDI产业技术的过度依赖.

  7. Grey Correlative Analyzing and Causal Model Structuring of Synergy Development of Urban Agglomeration%城市群协同发展的灰色关联分析与成因模型

    Institute of Scientific and Technical Information of China (English)

    刘耀彬

    2009-01-01

    The paper employs the synergism theory and grey correlative analysis to analyze the inner nonlinear relationships among factors of urban agglomeration, and build a factor model that can reveal the causal-result in the system of urban agglomeration. The results by grey correlative analysis show that urban agglomeration is an open and dissipative system, and it is affected by many factors, which are not simple linear causal-resuh relationships but relevant, non-uniformity, the irreversibility. And the factor model further reveals that the dominant parameters of urban agglomeration in Jiangxi Province are the rate of industrialization, urban fixed asset investment proportion of the total investment in fixed assets, and the highway mileage on per unit area, which are key driving factor in ur-ban agglomeration formation and evolution. Obviously, the simulated results are corresponding with the practice de-velopment of urban agglomeration in Jiangxi Province, so the nonlinear systematical methods can be applied to ana-lyze the mechanism of urban agglomeration development.%综合运用灰色关联技术和协同学方法,以江西省城市群为例,在对其城市群协同发展进行了灰色关联分析的基础上,建构了城市群协同演进的非线性微分成因模型,并通过数值模拟得到其系统发展的序参量.灰色关联分析发现,江西省城市群作为一个非线性的复杂大系统,其形成与演化受到众多因素的共同作用,而且它们之间不是简单的因果线性关系,具有相关性、非均匀性、不可逆性等;因子模型进一步揭示,对江西省城市群协同演化起支配作用的序参量是工业化率、城镇固定资产投资占全社会固定资产投资比重和单位面积的公路通车里程数,它们是城市群形成与演化中的关键动力因子.显然,模拟结果比较符合江西省城市群发展的实际,因此,这种非线性的综合处理方法可以进一步推广.

  8. 高铁对湖北省旅游产业集聚水平的影响%High-speed Rail Impact on the Agglomeration Level of Regional Tourism Industry in Hubei Province

    Institute of Scientific and Technical Information of China (English)

    胡静; 程露萍; 周密

    2015-01-01

    By using the herfindahl-hirschman index and space gini coefficient,the paper measures the agglomeration level about tourism industry of Hubei province in 2005—2012 was measured. The agglomeration level changes of tourism industry after high-speed opening were compared. The different impact of tourism and related industries were analyzed. The results show:1)after the high-speed rail opening in 2009,the agglomeration level of tourism industry has increased significantly in Hubei province;2) There are obvious differences in the influence that high-speed rail impacts to the tourism industry cluster in Hubei province,and the degree to business service industry and the accommodation catering industry is the largest;3)Nationally,the agglomeration level of tourism industry in Hubei province is low,and the growth rate is slow;4)The agglomeration degree of tourism industry is imbalanced in Hubei province,the agglomeration level of tourism industry has been increasing in transportation hub cities, such as Wuhan,Yichang;Finally,based on the present agglomeration situation of the tourism industry in Hubei province,some conclusions and suggestions were made.%利用赫芬达尔指数和空间基尼系数,测量湖北省2005—2012年旅游产业的集聚水平,对比高铁开通前后其旅游产业集聚水平的发展变化,分析高铁对旅游及相关行业的差异化影响。结果表明:2009年高铁开通以后,湖北省旅游产业的集聚水平显著提高;高铁对湖北省各旅游行业集聚水平的影响程度存在明显差异,其中对商业服务业、住宿餐饮业的影响程度最大;在全国范围内,湖北省旅游产业的集聚程度相对较低,且增长速度缓慢;湖北省内旅游产业的空间集聚程度不均衡,武汉、宜昌等交通枢纽城市旅游产业的集聚水平不断增强。针对目前湖北省旅游产业的集聚状况得出一些结论和建议。

  9. Impregnation/Agglomeration Laboratory Tests of Heavy Fuel from Prestige to Improve Its Manageability and Removal from Seawater Surface. (Physical Behaviour of Fuel Agglomates); Ensayos a Nivel de Laboratorio de Impregnacion/Aglomeracion del Fuel Procedente del Prestige para Facilitar su Manipulacion y Recogida en la Superficie del Mar (Comportamiento Fisico de los Aglomerados de Fuel)

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Frutos, F. J.; Rodriguez, V.; Otero, J.

    2002-07-01

    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 condition: 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.

  10. Evaluation of Industry Transfer Comprehensive Undertaking Ability of Six Major Urban Agglomerations in the Central Region%中部六大城市群产业转移综合承接能力评价研究

    Institute of Scientific and Technical Information of China (English)

    段小薇; 李璐璐; 苗长虹; 胡志强

    2016-01-01

    从产业承接地角度出发,以中部六大城市群为研究对象,基于前人研究的基础上选取7个2级指标和27个3级指标建立评价指标体系,运用主成分分析法对中部六大城市群产业转移综合承接能力进行评价,得出:① 从城市群层面看,城市群之间承接能力悬殊,各子系统水平差距大;② 从城市层面看,中心城市承接产业能力突出,但整体水平有待提高,高低梯度城市数量呈"两极分化"状态;③ 从总体看,城市群综合承接能力不仅受中心城市承接能力影响,也与城市群内非中心城市承接能力密切相关.基于相关的研究结论,有针对性地从成本因素、对外开放合作程度、市场吸引力、技术创新能力、产业配套能力、经济发展水平和产业结构水平7个方面给出了提高中部六大城市群产业承接能力的建议措施.%Industrial transfer is an effective method to promote economic development of the undertaking re-gions. Since 1930s research on industrial transfer had formed the flying-geese model, product life cycle theory, marginal industry expansion theory, the eclectic theory of international production ,overlapping industry theo-ry, and the theory of gradient and so on. Early empirical research is mainly about the transfer of industry be-tween developed countries. China's research on industrial transfer started in 1990s. The research content is mainly about the motive, the mode and the mechanism of the industry transfer, study on the ability of undertak-ing industry is still insufficient. As an important carrier of regional development, six central urban agglomera-tion plays an important role in transfering the industries of the eastern region, So, what are the differences of the undertaking capacity of the six major urban agglomerations in the central region? What are the strengths and weaknesses of different urban agglomeration to undertake industry? This is very important for different re

  11. Striving to Develop the Urban Agglomeration in South Shandong%关于大力发展鲁南城市群的研究

    Institute of Scientific and Technical Information of China (English)

    刘小平

    2011-01-01

    The economy in South Shandong province is relatively backward. How to achieve a great - leap - forward economic development is a subject worth studying. After observing and analyzing closely the four cities in South Shandong province, we found out that the total population is too big, while the city size is too small, that the center districts of cities are sparsely populated, while the countryside is overpopulated, that the industrialization is underde- veloped and the proportion of the tertiary industry is low. All the above factors are the primary causes for the relative backwardness in South Shandong areas. To solve this problem, we hold that we should develop the urban agglomeration located in Jining and Zaozhuang greatly, turning them into influential cities as Jinan and Qingdao so much so that they can lead the economic development of the whole South Shandong area. Our proposals are as follows: plan with high standard in advance and strive for privileged policies ; build high - speed rails to create a better environment for economic development; strive to develop private economy, and so on.%山东省的鲁南地区经济一直相对落后,如何实现鲁南地区的跨越式发展,是一个值得研究的课题。我们仔细观察分析鲁南四市,发现其总人口规模过大,但城市规模太小,中心城市区人口太少,农村人口太多,工业化水平低,第三产业比重低,导致本区域内的消费需求不足,小马拖不动大车是导致鲁南地区相对贫困落后的根本原因。因此,我们认为应当超常规发展位于济宁和枣庄市的鲁南城市群,使其成为济南、青岛这样的有影响力的大城市,从而带动辐射整个鲁南地区的经济发展。具体建议包括高标准超前规划、争取特殊政策、兴建日临济菏开郑高铁、创造良好的经济发展环境和大力发展民营经济等。

  12. Environment Optimization of Creative Enterprise Agglomeration Districts: Based on Competitive Advantages Perspective%创意企业集聚区环境优化设计——基于竞争优势视角的研究

    Institute of Scientific and Technical Information of China (English)

    陈颖

    2012-01-01

    建设创意企业集聚区是“十二五”期间城市加快创意产业发展的重要手段,各级政府纷纷出台创意企业集聚区的认定标准,但内容上参差不齐。本文构建了创意企业集聚区“环境六维度”对创意企业竞争优势的作用机制模型,随后在杭州市十家文化创意集聚区内采集了160份有效样本,运用结构方程模型对概念化模型进行数理化拟合。结果表明,政策支持、集聚区特色和入驻企业、地理区位、管理配套、孵化服务、集体声誉等环境要素,以创意企业智力资本(人力资本、结构资本、关系资本)为中介,对创意企业竞争优势产生作用。各级管理部门可以依据“环境六维度”优化设计创意企业集聚区认定标准,突出政策支持和集体声誉的重要性及全面性,发挥其余环境要素对提升企业竞争优势的针对性。%Building creative enterprise the development of creative industry level governments have set standards consistent with each other. This agglomeration districts is one of vital approaches to upgrade during the twelfth five-year plan period. Therefore, city- of creative enterprise agglomeration districts which were not paper builds a concept model that " six environmental dimensions" of creative enterprise agglomeration districts exert vital influences on competitive advantages of creative enterprises. Then it chooses 160 creative enterprises within Hangzhou's ten creative enterprise agglomeration districts as the sampling, and implements structural equation modeling to evaluate model-fit. The results show that those environmental dimensions, including policy support, features of agglomeration districts and settled enterprises, geographical location, management support, incubation service, collective reputation, exert vital influences on competitive advantages of creative enterprises via its interactions with creative enterprises intellectual

  13. 电凝并技术脱除P M2.5的研究现状及发展方向%Research status and development direction of electric agglomeration technology for PM2 . 5 removal

    Institute of Scientific and Technical Information of China (English)

    竹涛; 陈锐; 王晓佳; 夏妮; 赵文娟; 李笑阳

    2015-01-01

    In order to improve capture efficiency of traditional filter for PM2. 5,the agglomeration of homopolar and heteropole charged par-ticles in alternating electric field,coulomb agglomeration of heteropole charged particles,agglomeration of heteropole charged particles in direct-current electric field were introduced. The development direction of electric agglomeration was analyzed. The agglomeration effects of heteropole charged particles in alternating electric field was the best. The two-area filter had better fine particle capture performance than the three-area filter. The low temperature plasma electric agglomeration equipment was placed directly in pipe to precharge dust. A doub-le-beam electric cage bag filter was developed based on the original bag filter. Based on the new bag filter,a compound reactor which could remove S,NOx and Hg at the same time had tight structure and small volume. Its dust removal efficiency was able to reach 99%.%针对传统除尘器无法有效捕集P M2.5的问题,笔者论述了同极荷电颗粒在交变电场中的凝并、异极性荷电粉尘的库伦凝并、异极荷电颗粒在交变电场中的凝并、异极荷电颗粒在直流电场中的凝并、四级凝并5种电凝并技术的研究现状,并提出了电凝并技术的发展方向。5种电凝并技术中,异极荷电颗粒在交变电场中的凝并效果较好;两区式异极荷电颗粒在交变电场中的凝并效果优于三区式。低温等离子体-电凝并技术将低温等离子体-电凝并设备直接置于管道中,对粉尘预荷电;基于原有布袋除尘器开发出双踪电笼布袋除尘装置,联合脱除P M2.5。利用低温等离子体-电凝并技术开发的复合反应器结构紧凑,占地面积小,对细微粒子的除尘效率高达99%,可实现脱硫脱硝脱汞的协同脱除,是电凝并技术的发展方向。

  14. Effect of Nano-Silica Agglomeration on Hydration and Hardening of Cement%纳米二氧化硅团聚特性对水泥水化硬化性能的影响

    Institute of Scientific and Technical Information of China (English)

    孔德玉; 杜祥飞; 杨杨; Surendra P Shah

    2012-01-01

    Effect of nano-silica agglomeration on the hydration and hardening of cement was investigated by using precipitated silica (PS) with much larger agglomerates and nano-silica (NS) powder with much smaller ones as additives. The results reveal that the PS exhibits a higher pozzolanic reactivity at early ages and a better accelerating effect on the cement hydration though it possesses some larger agglomerates and a little lower pozzolanic reactivity at late ages rather than NS. The observation by scanning electron micros- copy indicates that the cementitious property of the pozzolanic C-S-H gels from the agglomerates was limited. There even existed an interfacial transition zone between the reacted agglomerates and bulk hardened cement paste (HCP). The MIP results show that the NS addition can reduce the capillary and the gel pore of the HCP in the range of 20nm-10 μm more effectively, compared to the PS addition. It is suggested that the effect of nano-silica addition on the microstmcture improvement of the HCP could be resulted fi'om the filling and water adsorbing effects of the agglomerates in the powder rather than the seeding effect.%以团聚粒径很大的沉淀二氧化硅(PS)和团聚粒径较小的纳米二氧化硅(NS)为原材料,研究了纳米二氧化硅团聚特性对水泥水化硬化特性的影响。结果表明:与 NS 相比,虽然 PS 团聚粒径很大,后期火山灰活性较低,其早期火山灰活性却较大,对水泥水化的促进作用也更明显。扫描电子显微镜分析表明,NS 和 PS 的火山灰反应产物的胶结作用有限,其与水泥水化产物本体之间甚至存在明显的界面过渡区。压汞分析表明:掺 PS 和NS 均可有效降低硬化水泥石毛细孔率;与掺 PS 相比,掺 NS 对减小 20 nm~10 μm 的凝胶孔和毛细孔体积更有利。掺纳米二氧化硅对硬化水泥石微观结构的影响主要是由于团聚颗粒对水泥分散体系的填充效应和吸水

  15. 基于多层核心集凝聚思想的视频关键帧提取%KEY VIDEO FRAME EXTRACTION BASED ON MULTILAYER CORE SET AGGLOMERATION THOUGHTS

    Institute of Scientific and Technical Information of China (English)

    杨臻; 杨志宏

    2015-01-01

    Key frame extraction is a key technology in video retrieval.Traditional key frame extraction algorithm has the problems of low accuracy and low recall and precision in video retrieval.For these problems,we proposed a key video frame extraction algorithm which is based on multilayer core agglomeration thoughts.First,we studied the multilayer core set agglomeration algorithm (MULCA)presented in literature [1 ],and utilised the characteristic of K-medoids algorithm-it uses real data as the clustering centre ! to improve two important processes of MULCA algorithm,the roughening of agglomeration and the refinement of agglomeration,we also substituted the original top layer core set derived from roughening process with it,designed a new multilayer core set agglomeration algorithm (IMULCA),and realised the fast and accurate positioning of top layer core set,which can appropriately reduce the agglomeration layer and simplify the computation complexity of the algorithm.Then,we applied the IMULCA algorithm to the extraction of key video frames.Experimental results showed that the proposed algorithm,compared with the previous algorithm,could more effectively extract the key video frame.%关键帧提取是视频检索的一项关键技术。针对传统的关键帧提取算法准确度低,视频检索的查全率和查准率不高的问题,提出一种基于多层核心凝聚思想的视频关键帧提取算法。首先,对文献[1]提出的多层核心集凝聚算法(MULCA)进行研究,并利用K-medoids算法用真实数据作为聚类中心的特性,对MULCA算法的凝聚粗化和凝聚细化两个重要过程进行改进,用其替代原粗化过程得到的顶层核心集,设计了一种新的多层核心集凝聚算法(IMULCA),实现了顶层核心集的快速准确定位,并可适当减少凝聚层数,简化了算法的计算复杂性。然后,将IMULCA算法应用到视频关键帧提取中,实验结果表明所提改进算法相对于

  16. 文化创意产业集聚效益分析--以北京市文化创意产业发展为例%Agglomeration Benefit Analysis for Cultural and Creative Industry---Taking Beijing as an Example

    Institute of Scientific and Technical Information of China (English)

    姜玲; 王丽龄

    2016-01-01

    集聚带来效益在很多产业领域得到证实,但是在文化创意产业领域全面集聚是否是有效的?论文针对文化创意产业集聚效益及其在产业间的差异,应用CES模型分析了北京市文创产业三大类细分产业的集聚效益及动因。研究发现,大多数文化创意产业的集聚总体上能够产生正效益,但某些细分产业的集聚达到一定程度后可能会出现负变化。进一步通过动因分析,提出分类引导集聚的必要性与建议。%The agglomeration benefit has been verified in many industries except for cultural and creative industry. It is of necessity to examine if the integral agglomeration policy for the industry is efficient. This paper studies whether the cultural and creative industrial agglomeration has benefits, and whether there is any difference within the segmentation industries with CES production function model. According to the paper, the agglomeration of Beijing ’ s majority segmentation industries of the cultural and creative industry has benefits, but could turn to reversals after over-agglomeration. According to the analysis for motivation of agglomeration, it is necessary to classify and guide agglomeration.

  17. Effect of Agglomeration on the Analysis of Particle Size Distribution of 5A Submicron Zeolite%团聚对亚微米5A分子筛粒度分析的影响

    Institute of Scientific and Technical Information of China (English)

    施露; 崔群; 王海燕

    2013-01-01

    为了考察小晶粒分子筛团聚对亚微米级5A分子筛粒度分布结果的影响以及适宜的测定条件,实验以水为分散介质,六偏磷酸钠为分散剂,在超声波辅助作用下,用电位/粒度分析仪测定研究了试样浓度、分散剂用量和超声时间对亚微米级5A分子筛分散性的影响.结果表明,当分子筛含量大于5 g/L时,晶粒团聚现象严重,粒度分布呈现单峰(假象),导致粒度测量结果偏大;加入少量(0.005~0.195g/L)的六偏磷酸钠,有缓解晶粒团聚作用,可将较大团聚粒子(大于2.8μm)分散为较小粒子(1.3μm左右),少量团聚粒子分散成单个晶粒,可测得较小晶粒粒径;超声作用可使较大团聚粒子(0.85~2.80 μm)分布峰强度降低,相对较小粒子(0.30~0.85μm)分布峰强度增加.超声时间不宜太长,否则将加剧粒子间团聚,使得测定粒径偏大.当试样中5A分子筛含量为5g/L,六偏磷酸钠浓度0.195g/L、超声时间4 min条件下,测得5A分子筛试样粒径分布0.25~0.80 μm,峰顶对应粒径为0.473μm,中位径(d50)为0.784μm,与电镜分析结果一致,说明是较为准确的粒度分析方法.%This paper discusses the effect of small grain agglomeration on the particle size distribution (PSD) of 5 A submicron zeolite and the appropriate measuring methods. Water and sodium hexametaphosphate were chosen as a disperse medium and a dispersant, respectively. The influences of zeolite concentration, dispersant dosage and time of ultrasonic treatment on the dispersion state were studied by a potential/particle size analyzer with ultrasonic treatment. Results show that when zeolite concentration is more than 5 g/L, the PSD appears to be a unimodal distribution (false appearance), leading to a large measured size due to severe agglomeration. A small amount of sodium hexametaphosphate (0.005-0.195 g/L) additive can alleviate the agglomeration by dispersing most large agglomerated particles (more than 2.8 μm) into

  18. Study on Co-Action between Urban Agglomeration and Co-Network with the Combination of Market and Industry, ' A case of Co-Action between Urban Agglomeration of Mid-Zhejiang and "Yiwu Business Circle"%城市群与协同型市场产业网络的协动机理研究——以浙中城市群与“义乌商圈”协动发展为例

    Institute of Scientific and Technical Information of China (English)

    郑小碧; 陆立军

    2012-01-01

    It reveals that urban agglomeration,market and industry is in evolution with the development of regional economy. Studies have pay lots of attention on the functions of each other to the regional economy growth. However, scholarships have not spent enough time to study the relationship among them. So, we give out two innovative conceptions, namely Co-network with the Combination of Market and Industry and Co-action between Urban Agglomeration and Co-network with the Combination of Market and Industry, then this essay builds an theory model to that. At the end, we take the Co-action between the Urban Agglomeration of Mid-Zhejiang and "Yiwu Business Circle"for example, in order to indicate the logical process and mechanism of Co-network with the Combination of Market and Industry further.%国内外发展实践表明,区域经济发展往往伴随着城市群、市场及产业经济系统的演进。现有研究也多关注到了三者各自对区域经济发展所具有的独特作用。在提出了“协同型市场产业网络”和“城市群与协同型市场产业网络协动”这两个概念后,构建了城市群与协同型市场产业网络协动的理论模型。最后,以浙中城市群与“义乌商圈”协动发展为例,实证分析了城市群与协同型市场产业网络协动的历史逻辑过程及内在机理。

  19. New-type driving forces of urban agglomerations development in China%中国城市群发育的新型驱动力研究

    Institute of Scientific and Technical Information of China (English)

    王婧; 方创琳

    2011-01-01

    Urban agglomeration (UA) is a new terrain unit involved in international competition and international division of labor. With the development of economic globalization and the boot of information and technology, UAs in China have developed gradually. In this process, five new-type driving forces (DF) have appeared, which are economic globalization, new-type industrialization, informatization, rapid transportation and government dominant, and studies on the five ones have important value. Based on analysis of mechanism of five new-type DF for UA and comparative analysis of some relative indexes, it is found out as follows: economic globalization drives UAs enter the international system and the higher level of UAs opening and the more industrial and technology transfers, the better UAs develop under the background of economic globalization; new-type industrialization drives UAs become manufacturing bases which injects new energies for development,and the higher level of industrialization and the better high-tech industry develops, the better UAs develop; informatization integrates all information and drives them flow at a high speed, and the higher level of informatization, the better UAs develop under the background of informatization age; transportation is the channel for materials and information exchange, and rapid transportation impels UAs to be connected closely and builds up the foundation of UAs development; new correlative policy is like a roll booster for impelling UAs development, in a correct way. Based on the above analysis, the paper suggests that further studies towards UAs development in China should focus on spatial and temporal differences of DFs and braking forces.%城市群是国家参与全球竞争和国际分工的全新地域单元,城市群发育对于推进城市化进程、增强综合国力具有显著作用,研究城市群发育驱动力具有重要价值.伴随着不断加强的全球化、信息化进程,中国城市群逐渐发育

  20. Difference Analysis of Information Service Industry Agglomeration Level in China%我国信息服务业集聚水平差异分析

    Institute of Scientific and Technical Information of China (English)

    程慧平

    2012-01-01

      通过区位熵指数对2001-2010年我国信息服务业人才集聚优势分析发现:东西中部地区呈现依次分布格局;京津冀、珠三角、长三角地区人才优势呈现依次减弱格局.并运用θi指数法分别对2001-2010年我国30省信息服务业劳动生产率、资本要素禀赋进行了差异比较分析.通过Spearman等级相关系数分析,发现劳动生产率、资本要素禀赋排序显著性相关,相关系数为0.329.通过劳动生产率与资本要素禀赋面板数据模型的Hausman检验,显示固定效应模型更适合,回归系数为0.7536,表示提高资本劳动要素配置结构有利于提高劳动生产率.最后,运用灰色关联分析方法,劳动生产率、资本要素禀赋角度对30省信息服务业产业集聚进行综合评价.%  The paper empirically analyzes the advantages of concentrating talents of information service industry in China from 2001 to 2010 by location entropy index and concludes that the eastern region is best, the next is the western region, and the last one is the middle re-gion. The Jing-Jin-Ji,Yangtze River Delta and Pearl River Delta present weakened in turn. The paper makes a difference comparative a-nalysis on labor productivity and capital factor endowment of 30 provinces in China from 2001 to 2010 by means of θi index. Through Spearman rank correlation coefficient analysis, the paper finds that the rank between labor productivity and capital factor endowment is sig-nificantly related, and the correlation coefficient is 0. 329. Fixed effects model is more suitable by Hausman test for the paneled model be-tween labor productivity and capital factor endowment, and the regression coefficient is 0. 7536. This means that improving allocation structure of capital and labor can increase labor productivity. At last, the paper evaluates industrial agglomeration level of information serv-ice industry of 30 provinces in China by using grey clustering method from the

  1. 声波团聚煤飞灰微粒强化旋风分离的试验研究%Experimental Research on Enhanced Cyclone Separation of Acoustic Agglomerated Particles

    Institute of Scientific and Technical Information of China (English)

    刘淑艳; 黄虹宾; 阎为革

    2000-01-01

    研究在试验冷态下,声场中煤飞灰微粒团聚后的坚固程度和分离效率. 对煤飞灰微粒在声场中团聚的现象进行试验研究,探索在冷态下声波增强旋风分离煤飞灰微粒的分离技术. 在声波声压级150dB的声场下,经声波辐射后的微粒强化旋风分离效率增加了3%-4%. 声波团聚微粒强化旋风分离的冷态试验,为高温下燃煤增压流化床燃烧联合循环中煤飞灰微粒分离的应用提供了技术基础.%To test the particles solidity and to verify the separating efficiency at normal atmospheric temperature, the experimental research was made on the enhanced cyclone separation of acoustic agglomerated fly-ash particles. The separating efficiency has increased by 3%-4% in a sound field with 150dB pressure level compared with that obtained without acoustic wave processing. The enhanced cyclone separation test study for acoustic agglomerated particles has provided a technical basis for pressurized fluid-bed combustion(PFBC) application.

  2. 随机取向内外混合凝聚粒子辐射特性%Radiative properties of internal/external mixture of agglomerates in random orientation

    Institute of Scientific and Technical Information of China (English)

    类成新; 吴振森; 冯东太

    2013-01-01

    The discrete dipole approximation method was used to compute the radiative characteristic parameters including the optical cross-sections, single-scattering albedo and asymmetrical parameter for a variety of mixed agglomerates in different mixing states at a visible wavelength 0.55μm. It is shown that the influence of the mixing states on the asymmetrical parameter is very great, and that on the scattering cross section and single-scattering albedo is heavy, while that on the absorption and extinction cross sections is not obvious. The influence of mixing patterns on the asymmetrical parameter, scattering cross section and single-scattering albedo is becoming more obvious with the increase of the size of agglomerates. The mixture ratios has an obvious effect on the radiative characteristic quantities of agglomerates in internal and external mixing states, and the effect varies with the monomer diameters, and number of monomers in the agglomerates. The scattering cross-sections of external mixture of agglomerates are larger than those of their internally mixed counterparts, but the single-scattering albedo decreases accordingly at the same mixture ratios.%采用离散偶极子近似方法对随机取向混合凝聚粒子在内外混合状态下的光学截面、单次散射反照率以及非对称因子等辐射特性参量进行了数值计算,详细讨论了混合方式、混合比等因素对混合凝聚粒子辐射特性的影响。研究表明,混合凝聚粒子的混合方式对非对称因子的影响非常大,对散射截面和单次散射反照率的影响比较大,但是对吸收和消光截面的影响不明显。随着凝聚粒子中基本粒子粒径和数量的增大,非对称因子、散射截面以及单次散射反照率受混合方式的影响变得愈加明显。此外,混合比的变化对不同混合状态下的凝聚粒子的辐射特性参量均存在不同程度的影响,并且此影响随着基本粒子粒径和数量的变

  3. Cou ntermeasures of the Sustainable Development of Central Plains Urban Agglomeration Traffis Circle%中原城市群交通圈可持续发展的对策

    Institute of Scientific and Technical Information of China (English)

    徐宏平; 薄爱敬

    2015-01-01

    Nowadays transportation in Central Plains Urban Agglomeration cann't the demand of the rapid development of social economy , which beginsto expose signs of insufficient capacity of traffic channels, decreasing efficiency of the inter-city traffic, more serious traffic jams in central city, structural imbalance of integrated transport and weak development of resources-saving and environ-ment-friendly systems.So the problems of traffic circle of Central Plains Urban Agglomeration need to be analyzed and researched scientifically and urgently in order to speed up the construction of com-prehensive traffic system of urban agglomeration in Henan province.This paper analyzed the existing problems of transportation in Central Plains Urban Agglomeration,the demands and influences of de-velopment of Grain Production Core Area Construction in Henan Province, the Central Plains Eco-nomic Zone and the Airport Economic Comprehensive Experimental Area.In turn, on the basis of the above research results this paper proposed many countermeasures that are suitable for the sustainable development of traffic circle of Central Plains Urban Agglomeration as follows: constructing modern and comprehensive transportation hub, giving priority to the development of the civil aviation, speed-ing up the railway construction, further perfecting the highway network and infrastructure of the city traffic, improving the management of inland water transportation and optimizing the city transportation environment.%目前中原城市群交通还不能满足社会经济快速发展需要,存在交通通道运力不足、城际交通效率低下、中心城市交通日益拥堵、综合运输结构失调、两型系统(资源节约型、环境友好型)发展乏力等问题。迫切需要对中原城市群交通圈问题进行科学规划和研究,加快我省城市群综合交通系统建设进程。分析中原城市群交通存在的问题,探讨河南省全国粮

  4. Reduced ash related operational problems (slagging, bed agglomeration, corrosion and fouling) by co-combustion biomass with peat; Minskade askrelaterade driftsproblem (belaeggning, slaggning, hoegtemperatur-korrosion, baeddagglomerering) genom inblandning av torv i biobraenslen

    Energy Technology Data Exchange (ETDEWEB)

    Oehman, Marcus; Boman, Christoffer; Erhardsson, Thomas; Gilbe, Ram; Pommer, Linda; Bostroem, Dan; Nordin, Anders; Samuelsson, Robert; Burvall, Jan

    2006-12-15

    Combustion studies were performed in both a fluidized bed (5 kW) and in an under-feed pellets burner (20 kW) to elucidate the responsible mechanisms for the positive effects on ash related operational problems (i.e. slagging, fouling, corrosion and bed agglomeration) during co-combustion of several problematic biomass with peat. Three typical carex-containing Swedish peat samples with differences in e.g. silicon-, calcium- and sulfur contents were co-fired with logging residues, willow and straw in proportions corresponding to 15-40 weight %d.s. Mixing of corresponding 20 wt-% of peat significantly reduced the bed agglomeration tendencies for all fuels. The fuel specific agglomeration temperature were increased by 150-170 deg C when adding peat to the straw fuel and approximately 70-100 deg C when adding peat to the logging residue- and the willow fuel. The increased level of calcium in the inner bed particle layer caused by the added reactive calcium from the peat and/or removing alkali in the gas phase to a less reactive particular form via sorption and/or reaction with reactive peat ash (containing calcium, silica etc.) during which larger particles (>1{mu}m) are formed where collected potassium is present in a less reactive form, is considered to be the dominated reason for the increased agglomeration temperatures during combustion of logging residues and willow. During straw combustion, the ash forming matter were found as individual ash sticky particles in the bed. The iron, sulphur and calcium content of these individual ash particles were significantly increased when adding peat to the fuel mix thereby decreasing the stickiness of these particles i.e. reducing the agglomeration tendencies. Adding peat to the relatively silicon-poor fuels (willow and logging residues) resulted in higher slagging tendencies, especially when the relative silicon rich peat fuel (Brunnskoelen) was used. However, when co-combusting peat with the relatively silicon and potassium

  5. Regional Scale ,Agglomeration Externalities and Regional Innovation Capability——Based on the Threshold Effect of China's Industrial Sector%地区规模、集聚外部性与区域创新能力——对中国工业行业的门槛效应检验

    Institute of Scientific and Technical Information of China (English)

    张秋燕; 齐亚伟

    2016-01-01

    This paper ,using the data of 27 Industries in China's 30 provinces from 2005 to 2013 ,builds panel threshold mod-el to analyze the impact of diversification agglomeration (Jacobs externalities) ,specialized agglomeration (M A R externali-ties) and enterprise competitiveness on the regional industry innovation ability for different regions empirical scale .The re-sults show that when regional scale is smaller ,diversification agglomeration ,specialized agglomeration and enterprise com-petitiveness are significantly positive correlated with regional industrial innovation capability ,but with regional scale increa-ses ,the promotion of diversification agglomeration on regional industrial innovation capability is significantly reduced .And there is inverted"U"shaped relationship between specialized agglomeration ,enterprise competitiveness and regional indus-trial innovation capability .%采用2005-2013年中国内地30个地区(除西藏外)27个工业行业数据,构建面板门槛模型,实证检验不同地区规模下,区域内多样化集聚(Jacobs外部性)、专业化集聚(M AR外部性)和企业竞争对区域创新能力的影响.结果显示,当地区规模较小时,多样化集聚、专业化集聚与企业竞争都对区域创新能力具有显著促进作用,但随着地区规模的日益增大,多样化集聚对区域创新能力的促进作用明显减小;专业化集聚、企业竞争与区域创新能力之间存在倒U型关系.

  6. 汨罗市“城市矿产”产业集群的“生态位”测度分析%Analysis of “Ecological Niche” Evaluation Indexes of “Urban Mining” Industrial Agglomeration of Miluo City

    Institute of Scientific and Technical Information of China (English)

    鲁波; 刘泰子

    2012-01-01

    以汨罗市“城市矿产”产业集群为研究对象,借鉴种群生态学中“生态位”概念,建立“城市矿产”产业集群“生态位”测度模型,运用德尔菲法、层次分析法和图形诊断法进行比较分析,研究得到汨罗市“城市矿产”产业集群“生态位”对比国内其他主要“城市矿产”基地整体上处于劣势水平,并提出相关优化对策:扩大汨罗市“城市矿产”产业集群“生态位”,提高综合竞争力,推动汨罗“城市矿产”产业集群全面升级.%Based on the concept of "ecological niche" in population ecology, "urban mining" industrial agglomeration of Miluo city is taken as research object. The "ecological niche" evaluation model of "urban mining" was built. Delphi methods, analytic hierarchy process and graph diagnosis are used to diagnosis the Miluo "urban mining" industrial agglomeration, which indicats that Miluo "urban mining" industrial agglomeration is falling behind the other civil "urban mining" industrial agglomeration. Some optimal opinions are proposed in order to broaden the "ecological niche" of Miluo "urban mining" industrial agglomeration, improve the integrated competitive capability, promote the "urban mining" industrial agglomeration of Miluo city to a higher grade.

  7. INFLUENCE OF THE CAPILLARY AGGLOMERATION IN POROUS MEDIA ON THE DEW POINT OF CONDENSATE GAS RESERVOIR%多孔介质毛细凝聚对凝析气藏露点的影响研究

    Institute of Scientific and Technical Information of China (English)

    杜建芬; 李士伦; 孙雷; 何江川

    2001-01-01

    凝析气藏流体处于地下多孔介质中,由于多孔介质孔隙壁面的影响,毛细凝聚现象必然存在,从而不可避免地会对反凝析过程产生影响,以致影响凝析气藏的露点。为此,文章在分析毛细凝聚对凝析气藏露点影响机理的基础上,结合流体相平衡的基本理论,建立了考虑多孔介质毛细凝聚影响的凝析油气体系露点预测的相平衡计算数学模型,并结合实例计算分析研究了储层孔隙半径、润湿性等对露点的影响程度。结果表明,亲油岩石毛细凝聚使露点上升,憎油岩石毛细凝聚使露点下降;当润湿性相同时,毛管半径越小,露点所受影响的程度越大;当孔隙半径大于5×10-6cm时,毛细凝聚对凝析气藏露点的影响程度很小,而当小于5×10-6cm时,露点所受的影响较明显。最后得出结论,对于高孔渗型储层,将毛细凝聚的影响忽略不会影响到相平衡理论的准确性;但对于低渗透气藏,毛细凝聚则对露点有较明显的影响作用,在实际工程应用中,应当考虑。%The fluids in condensate gas reservoir are set in subsurface porous media and a capillary agglomerating phenomenon occurs inevitably owing to the effect of pore wall surface in porous media,thus influencing the retrograde condensate process and the dew point of condensate gas reservoir unavoidably.For this reason,in the paper,on the basis of analyzing the mechanism of the influence of capillary agglomeration on the dew point of condensate gas reservoir,a phase equilibrium calculation mathematical model of predicting the dew point of condensate-gas system in consideration of the effect of the capillary agglomeration in porous media is set up in combination with the fundamental theory of phase equilibrium,and the degree of influence of the pore radius and wettability,of reservoir on the dew point is analyzed and researched by calculating a case.It is indicated that

  8. The Empirical Research on Industrial Agglomeration, Ways of Technology Innovation and Export of High-tech Enterprises%产业集聚、技术创新途径与高新技术企业出口的实证研究

    Institute of Scientific and Technical Information of China (English)

    宣烨; 宣思源

    2012-01-01

    Based on the theoretical hypothesis,the paper try to reveal the effects of industrial agglomeration,ways of technology innovation to the export of high-tech enterprises using the data of high-tech enterprises from Jiangsu province.The results show that industrial agglomeration has significant positive effect to export.Relative to technology introduction,absorption and secondary innovation,self-dependant innovation promote export of enterprises obviously.Further research shows that enterprises exist in an industrial agglomeration do not mean that they are sure to obtain agglomeration effects to promote export abilities.The premise to get agglomeration effects for enterprises in an agglomeration is to integrate into the production division network,or into the industrial chain or product chain of the industrial agglomeration.According to this,the paper puts forward the proposals to foster enterprises’ abilities of self-dependent innovation and give full play to industrial agglomeration effects in order to promote enterprises’ competitiveness.%在提出产业聚集、技术创新途径对企业出口影响理论假说的基础上,文章利用江苏高新技术企业数据,试图揭示产业集聚、技术创新途径对高新技术企业出口的影响。结果显示,产业集聚对企业出口具有显著的正向作用;相对于技术引进、消化吸收与二次创新,自主创新对企业出口的促进作用最为明显。进一步研究发现,企业居于产业集群内并不意味着就一定能够获取集聚效应从而引致出口能力的提升,集群内企业获取集聚效应的前提是能够融入产业集群式生产分工网络,或是融入产业集群产业链与产品链。据此,文章提出了培育企业自主创新能力、发挥产业集群效应以促进企业竞争力提升的政策建议。

  9. Correlation between regional agglomeration and performance of tourism industry——A case study of 31 provinces of China%区域旅游产业集聚与绩效的关系研究——基于中国31个省区的实证

    Institute of Scientific and Technical Information of China (English)

    王凯; 易静

    2013-01-01

    利用Gini系数、E-G指数、行业地区集中度等产业集聚指标以及产业利润率、就业系数、劳动生产率等产业绩效衡量指标,基于2010年的截面数据,探究中国旅游产业集聚化发展及其与产业绩效之间的关系.结果表明:整体旅游产业的集聚程度较低,但产业内部各行业的区域集聚特征明显;旅游产业集聚程度的区域差异与区位条件差异具有较高的一致性;旅游产业集聚总体上对产业绩效的提高具有积极影响,其中,旅游产业集聚对产业利润率和劳动生产率的提高有显著的正向影响,但是对于就业机会的增加影响甚微.基于上述结论,提出相关政策建议.%Based on the cross-section data in 2010, by using industrial agglomeration indexes such as Gini coefficient, E-G index and regional concentration ratio, and industrial performance measurement indexes such as profit margins, employment coefficient and labor productivity, this paper discusses the relationship between the spatial agglomeration and performance of tourism industry in China. The results indicate that agglomeration of China's tourism industry is overall fairly low, but the internal sectors of tourism industry are showing clear characteristics of regional agglomeration. There's a high consistency between the spatial differences in the degree of agglomeration of tourism industry and the differences in the level of regional socio-economic development in China. Generally speaking, the agglomeration of tourism industry has positive effects on the improvement of the performance of the industry. Especially, the spatial agglomeration has significantly positive impacts on the increase of profit margins and labor productivity, but very little impact on the increase of employment opportunities. On the basis of above findings, relevant countermeasures are put forward aiming at the improvement of the performance of agglomerated tourism industry in China.

  10. 长江经济带城市群联动发展机制研究%Joint Development Mechanism and Countermeasures of Urban Agglomerations in the Yangtze River Economic Belt

    Institute of Scientific and Technical Information of China (English)

    胡艳; 丁玉敏; 孟天琦

    2016-01-01

    长江经济带城市群联动发展对长江经济带国家战略的实施具有重要意义。长江经济带城市群联动发展的轨迹表明,联动发展应突出长三角城市群的首位度效应,发挥其对长江中上游城市群的带动作用。联动发展的关键在于构建长江经济带城市群联动发展机制,例如依托长江黄金水道,建立一体化航道运输管理机制;坚持市场引导与政府主导相结合、企业主体与社会参与相结合的原则,建立全方位、多层次的区域合作交流机制;树立“共赢、联动、协同”的发展理念,构建上中下游城市群区域间的利益共享机制。%The joint development of urban agglomeration in the Yangtze river economic belt is of great significance in the implement of national strategy. The Yangtze river economic belt linkage development trajectory suggests that we should concern the primacy effect of urban agglomerations and play its leading role. The key of linkage development is to construct urban agglomeration joint development mechanism of the Yangtze river economic zone. For example, we can establish integrated waterway transport management mechanism relying on the Yangtze river golden waterway, construct a comprehensive and multi-level regional cooperation mechanism by adhering to the combination of market guide and government leading, enterprise main body and the principle of combining social participation, and build on the middle and lower reaches of the benefit sharing mechanism between the urban areas by setting up win-win, linkage, cooperative concept of development.

  11. Influence de la taille de depart, de l'etat d'agglomeration et de la dose de nanoparticules de dioxyde de titane (TiO2) inhalees sur la reponse pulmonaire chez le rat

    Science.gov (United States)

    Noel, Alexandra

    It is estimated that by 2014 more than 10 million jobs related to the nanotechnology field will be created worldwide. It is therefore important to investigate the possible health effects caused by nanoparticles (NP). Due to their small size, NP ( 100 nm) (LA) at 2, 7 and 20 mg/m3. Similarly, four other groups of rats were exposed to aerosols at 20 mg/m 3 with a primary particle size of 10-30 and 50 nm. The different aerosols were generated by nebulization of suspensions or by dry dispersion. For each mass concentration, one group of control rats (n = 6 per group) was exposed to compressed air under the same conditions. The size, shape, structure and agglomeration state of NP in both the bulk powders and the generated aerosols were characterized by transmission electron microscopy and using an electrical low pressure impactor. Mass concentrations were determined by gravimetric measurements. The animals were sacrificed 16 hours after the end of exposure, and analysis of the bronchoalveolar lavage fluids was used to measure markers of inflammatory (total and differential cell counts, as well as various cytokines: IL-1alpha, IL-6, MIP-1alpha, MCP-1 and TNF-alpha), cytotoxicity (lactate dehydrogenase (LDH), alkaline phosphatase and total protein concentration) and oxidative stress (heme oxygenase-1, glutathione and 8-isoprostane) effects. Lung sections were also analyzed for histopathology. The influence of the agglomeration state of TiO2 NP (5 nm) could not be determined at 2 mg/m3. For mass concentrations of 7 and 20 mg/m3, our results showed that an acute inflammatory response (increase in the number of neutrophils) was induced following exposure to LA aerosols. In addition to this response, exposure to SA aerosols resulted in a significant increase in 8-isoprostane and LDH. At 20 mg/m3, the cytotoxic effects were greater after exposure to the 5-nm NP in the SA aerosol. Given the significant work done to generate and characterize aerosols, this study showed that TiO2

  12. 辽中南城市群新型城市化战略研究%Research the New Type Urbanization Strategy of Urban Agglomeration in Central and South Liaoning

    Institute of Scientific and Technical Information of China (English)

    王晓玲

    2014-01-01

    Defects of traditional urbanization mode in the development process displayed it was difficult to continue . New type urbanization is an inevitable choice for economic structure transformation and city ’ s sustainable develop-ment in China .As the most important growth pole , the road of new type urbanization of urban agglomeration in cen-tral and south Liaoning will promote deepening of revitalization of old industrial base .The paper analyzes the con-notation, the goal, the motivation, the characteristic and the index system of new type urbanization through litera-ture method , explores the plight of urban agglomeration in central and south Liaoning towards new type urbaniza -tion.It draws the following conclusion:the new type urbanization of urban agglomeration in central and south Lia-oning should take the strategy that medium and small cities will be given priority to develop as a breakthrough .It also should take harmonious development of large , medium and small city as the lead , and take the improvement of city quality as the ultimate goal .%传统城市化模式在发展过程中暴露的缺陷显示出其难以为继,新型城市化是我国经济结构转型、城市可持续发展的必然选择。辽中南城市群作为东北地区最为重要的增长极,其新型城市化道路将推动老工业基地振兴战略的深化。通过文献法分析了新型城市化的内涵、目标、动力、特征和指标体系,探索了辽中南城市群走新型城市化之路所面临的困境,得出如下结论:辽中南城市群新型城市化之路应以中、小城市优先发展战略为突破,以大、中、小城市和小城镇协调发展为主导,以全面提高城市化质量为最终目标。

  13. 二元城镇化:在集聚中兼顾平衡的高质量城镇化发展道路%Binary Urbanization:High Quality Urban Development Path Considering the Balance of Agglomeration

    Institute of Scientific and Technical Information of China (English)

    李华

    2014-01-01

    The essence of urbanization lies in spatial agglomeration, economics activities of gathering labor,capital,technology and information.The development of urbanization with high quality has to solve the paradox of agglomeration and diffusing.As is considered China’s industrial agglomeration and transfer,there exists reasonable and accessible development path of urbanization, which deliberately and elaborately considers the efficiency of agglomeration and fairness of rural and urban space.That is the vigorous development of a large metropolitan area depending on the development of the eastern coastal cities and major cities with suitable situations and resources in the central and western regions,associated at the same time with urbanization in cities of small and middle size and scale hinging on country development in relatively marginal and backward areas outside the metropolitan area.In the process of a binary urbanization path of development with high quality,not only the institutional obstacle for resources transportation and factor mobility should be abolished,but also the connection between urban and rural space should be established.%城镇化是由产业空间集聚带动人口空间集聚,进而带动资金、技术、信息等一系列要素在空间上集中的过程。高质量的城镇化发展面临集聚与平衡的矛盾。结合中国产业发展在空间上表现出的集聚和转移的现状及趋势,存在着基于产业空间布局变化、兼顾集聚经济发展的“效率”和城乡空间平衡发展的“公平”的高质量“二元城镇化”发展道路,即一方面强调集聚,以东部沿海大城市及中西部地区有条件的大城市为依托,大力发展表现为大都市圈特征的城市化;另一方面兼顾平衡,在都市圈以外的相对边缘和落后地区,依托县城发展中小城市,推进有重点的农村城镇化。在推进高质量“二元城镇化”的发展过程中,要破除各种

  14. The influence of the preparation of lignin bio-resins used in oil spilled agglomeration; A influencia do uso da lignina na preparacao de bioresinas utilizadas na aglomeracao de oleo derramado

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Joao Felipe T.; Silva, Thaissa P.; Ferreira, Leticia P.; Delazare, Thais; Souza Junior, Fernando G. [Instituto de Macromoleculas Professora Eloisa Mano - IMA/Universidade Federal do Rio de Janeiro - UFRJ, RJ (Brazil)], e-mail: fernando_gomes@ima.ufrj.br

    2011-07-01

    Locate petroleum, an energy source which spent millions of years to be formed, requires a lot of knowledge and technology, beyond large investments. However, along extraction, storage or transport of oil, there is a real risk of spills take place, causing extensive damage to the environment. Experience acquired due to accidental oil spills shows the large extension of damage imposed to the environment, impacting marine life, fishing and even tourism. Thus this study proposes the use of renewable sources, aiming to create an {sup g}reen absorbent material{sup .} This material is obtained through a polycondensation among lignin, furfural and cardanol, catalyzed by a strong acid. Synthesized bio-resin presents a good chemical similarity with oil, due to the tuning of its aromatic / aliphatic compounds, producing a strong physical interaction between the resin and oil, making the agglomeration process easy and contributing for the cleanup of oil spilled on water. (author)

  15. The influence of the preparation of lignin bio-resins used in oil spilled agglomeration; A influencia do uso da lignina na preparacao de bio-resinas utilizadas na aglomeracao de oleo derramado

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Joao Felipe T.; Pereira, Thaissa; Ferreira, Leticia P.; Delazare, Thais; Souza Junior, Fernando G. [Instituto de Macromoleculas Professora Eloisa Mano - IMA/Universidade Federal do Rio de Janeiro - UFRJ, RJ (Brazil)], e-mail: fernando_gomes@ima.ufrj

    2011-07-01

    Locate the oil, a source of energy that took millions of years to be formed is a task that requires much knowledge and technology, and large investments. However, during its operation, storage or transportation of oil, the risk of spills occurring in potential that can cause extensive damage to the environment. Experience of major accidental oil spills has shown the importance of damage to the environment, harming marine life, fishing and tourism. Thus this study aims to evaluate the use of renewable sources to create an 'absorbent green' by using the lignin, furfural and cardanol, being catalyzed by sulfuric acid. This bio-resin synthesized shows good chemical similarity with oil, because it has both aromatic and aliphatic compounds, thereby facilitating the strong physical interaction between the resin and oil, allowing the agglomeration process in the same lake environments. (author)

  16. On the Agglomeration Effect and Cultivation Function of GEM to Innovative Enterprises%创业板对创新型企业的吸聚效应禾培育功能.

    Institute of Scientific and Technical Information of China (English)

    梁军; 周扬

    2012-01-01

    GEM's promoting function to enterprise innovation includes agglomeration effect and cultivation effect. In this paper, I use the treatment effect model to control GEM variable endogene- ity bias, by collecting respectively 201 SMEs and 179 GEM board listed Corporation data from 2007 to 2011, make empirical research and examine whether GEM promote enterprise innovation ability. The empirical result shows that GEM's agglomeration effect to enterprise innovative is obvious, but its cultivation effect is not ideal. Finally, according to empirical results, I put forward policy and suggestion for next step of construction of GEM.%创业板对于企业创新的推动作用包括吸聚效应和培育效应。本文利用处理效应模型以控制创业板变量内生性偏误问题,分别采集20l家中小板上市公司和179家创业板上市公司2007年至2011年的相关数据进行实证研究,以考量创业板是否促进了企业创新能力的提升。实证分析表明,创业板对创新型企业的吸聚效应十分明显,但培育效应并不理想。本文最后根据实证结果对中国创业板下一步的建设提出了政策建议。

  17. 制造业区域集聚与技术创新:基于负二项模型的实证分析%Industrial Agglomeration and Innovation: An Application of the Negative Binomial Model

    Institute of Scientific and Technical Information of China (English)

    张萃

    2012-01-01

    Based on the localization character of knowledge spillover, this paper examines the impact of Chinese industrial agglomeration on innovation from the spatial view by using the negative binomial regression model. The empirical evidence through the maximum likelihood estimation shows that industrial agglomeration's innovation effect is significant, which has also been supported by the extended regressions on the high-innovation industry and the high-agglomeration industry. In addition, FDI has no impact on the innovation of the high-innovation industry and the domestic firms seem to promote the innovation of the foreign firms.%本文以知识溢出的地方化(localization)特性为前提条件,从空间视点切入,首次运用负二项回归模型实证考察了中国制造业区域集聚对技术创新的影响。通过最大似然估计得出的结果表明,制造业区域集聚之技术创新效应非常显著。这一结论也得到了对高创新行业和高集聚行业拓展回归分析的支持。研究还显示,FDI对高创新行业的技术创新作用并不显著,反而出现了内资企业向外资企业逆向技术扩散的可能。

  18. 产业转移加速进程中中国制造业集聚度再测算与演进%Measure and Evolution of China's Manufacturing Industry Agglomeration Degrees in the Process of Accelerating Industrial Transfer

    Institute of Scientific and Technical Information of China (English)

    周华蓉; 贺胜兵

    2015-01-01

    Industry transfer catalyzes the evolving trend of spatial agglomeration degree of China's manufacturing industry , We measure the degree of manufacturing industry agglomeration based on industrial concentration and spatial Gini coeffi‐cient since the 2008 financial crisis .According to the survey results ,We need to further promote the coastal industry main‐ly transfer to the central and western regions ,and realize gradient transfer to ASEAN countries .Both the eastern coastal areas and the central and western regions can attract high‐tech industries by virtue of their own advantages ,and actively implant the global value chain system ,Coastal areas developing high‐tech industries need to attent the excessive concentra‐tion and overcapacity problem .%产业转移催化了中国制造业空间集聚的演变趋势。利用行业集中度指标和空间基尼系数指标测算了2008年金融危机以来中国制造业的集聚程度,根据测算结果,需要进一步诱导和推进沿海产业向中西部地区转移,同时实现中国与东盟各国产业梯度转移,东部沿海地区和中西部地区均可凭借自身优势吸引高新技术产业入驻,并积极嵌入全球价值链体系,沿海地区发展高技术产业要注意过度集聚和产能过剩问题。

  19. 河北省产业集聚与人力资本集聚的机制研究%Study on the correlation between industrial agglomeration and human capital accumulation in Hebei province

    Institute of Scientific and Technical Information of China (English)

    贾冀南; 袁修月

    2011-01-01

    With China' s rapid economic development, industrial clustering phenomenon has become increasingly evident, and plays an important role in China' s economic growth. Taking industrial agglomeration and human capital accumulation in Hebei province for example, this paper presents a detailed analysis of the current development of industrial concentration and human capital accumulation. According to the data of Hebei Province, a linear regression model, which is about the flow of human capital and industrial concentration level, is built to study the correlation between the industrial agglomeration and human capital accumulation. Finally, an interactive path promoting level of industry concentration and the human capital accumulation is proposed.%随着我国经济的快速发展,产业集聚的现象也越来越明显,并且在我国的经济增长中发挥着重要的作用。文章以河北省产业集聚和人力资本的积聚为例,详细分析了河北省产业集聚水平以及人力资本积聚的现状,并在此基础上构建了河北省人力资本流量与产业集聚水平的线性回归模型,研究了两者之间的相关性,据此提出了促进河北省产业集聚水平与人力资本集聚互动的路径。

  20. 基于超效率DEA模型的城市群生态效率研究——以长株潭“3+5”城市群为例%Urban Agglomerations Eco-efficiency Analysis Based on Super-efficienty DEA Model:Case Study of Chang-Zhu-Tan "3 + 5" Urban Agglomeration

    Institute of Scientific and Technical Information of China (English)

    付丽娜; 陈晓红; 冷智花

    2013-01-01

    Circular economy is an important model of regional sustainable development, eco-efficiency approach is a comparatatively appropriate quantitative methods for studying circular economy. Regarding to Chang-Zhu-Tan ( Changsha-Zhuzhou-Xiangtan) "3 +5" urban agglomeration, this paper firstly establishes the input and output index system of eco-efficiency based on the DEA model, and calculates the efficiency in eight cities from 2005 to 2010 by using super-efficient DEA method, respectively. Then the dynamic comparative study of eco-efficiency has been done by using Malmquist-DEA model. The paper uses super-efficient DEA method to estimate the efficiency of the cities in 2005 -2010, and finally the Tobit model based on panel data has been developed to study the effect of the efficiency at different factors. The results showed the higher level of holistic eco-efficiency in urban agglomerations the larger differences among cities, Changsha is on the leading position of the provincial capital cities. By using Malmquist-DEA model analysis the results showed that the growth rates of total factor eco-efficiency TFP value are always larger than 1 , with an average annual growth rate of 12. 6% . The further decomposition of growth rates indicates that the technical progress is the major power to promote the growth rate of eco-efficiency, but the decline of the overall and pure technical efficiency is the bottleneck factor of restricting TPF ascension. At the last, the results of using factor analysis of eco-efficiency in provinces showed that the industrial structures, R&D strength had a significant positive impact to eco-effciency, but the introduction of foreign capitals has a negative effect to the eco-effciency. The development of technology is the internal driving force to a improvement of the ecological efficiency.%循环经济是区域实现可持续发展的重要模式,生态效率方法是研究循环经济比较适合的定量方法.本文以长株潭“3+5”城市

  1. 长江中游城市群区域一体化的测度与比较%REGIONAL INTEGRATION OF THE YANGTZE RIVER MIDDLE REACHES URBAN AGGLOMERATIONS:MEASURING AND COMPARISON

    Institute of Scientific and Technical Information of China (English)

    李雪松; 孙博文

    2013-01-01

    实现长江中游城市集群区域一体化,既能承接东部地区产业转移,也能够向西部传递发展势能,缩小西部与中东部的差距.参照了世界银行从密度、距离与分割3个维度对区域一体化的界定,构建了区域一体化评价体系;采用2000~2010年数据,并结合层次分析法对长江中游城市集群内部区域一体化进行测度与比较分析.研究显示:(1)长株潭城市圈区域一体化水平最高,武汉城市圈次之,环鄱阳湖生态经济区最低,但三大城市群一体化水平都呈现逐渐增长趋势;(2)三大城市群在市场一体化、行政一体化及社会一体化变化水平差异明显但总体差距逐渐缩小;(3)武汉城市圈在“两型”社会建设推动下一体化水平稳步提升,长株潭城市群一体化水平进程最快,环鄱阳湖生态经济区后发优势明显.在此基础上,提出了构建长江中游城市集群经济发展联动机制的政策建议.%Since the development strategy of central China was carried out,three urban agglomerations as Wuhan City Circle,Changsha-Zhuzhou-Xiangtan City Cluster and Poyang Lake Ecological Economic Zone have been formed along the middle reaches of the Yangtze River.It is the basic and strategic direction for the Yangtze River Middle Reaches Urban Agglomerations to carry forward the integration process,promote the regional updating of industrial structure and forge the fourth pole of Chinese economic development.Apparently,the accelerating of regional integration of the Yangtze River Middle Reaches Urban Agglomerations is not only beneficial to carry on the competitive industry transferring to promote locative industry development,but also is beneficial to promote the development of the Central Henan Urban Agglomeration and deliver the developing potential energy of eastern areas toward the western areas,thus narrowing the development gap between western areas and eastern ones,which are of great significance.In this

  2. Discrete element simulation of impact disaggregation for wet granule agglomerate%湿颗粒聚团碰撞解聚过程的离散元法模拟∗

    Institute of Scientific and Technical Information of China (English)

    焦杨; 章新喜; 孔凡成; 刘海顺

    2015-01-01

    Based on the combination of linear contact model, Coulomb slip contact model and parallel bond contact model, a discret element model (DEM) of wet granule agglomerates with coating structure is constructed. Disaggregation pro-cesses of wet agglomerates in impacting to a horizontal plate are performed by applying particle flow code (PFC). Three failure patterns are obtained corresponding to those in experiment. The variation of velocities and rupture characteristics of liquid bridge in disaggregation process are investigated. Effects of impact velocity, gravity of adhered granules, and rotation of core granule are analyzed. DEM simulations show that there are three disaggregation patterns in the coat-ing structure of agglomerates: impact disaggregation, gravity-impact disaggregation and shear-impact disaggregation, depending on the size of primary particles and the rotation of the core granules. With the enlargement of size, gravity plays an increasingly important role and the impact disaggregation pattern shifts to gravity-impact disaggregation. The rotation of core can generate a shear force to separate the fine and disaggregation pattern to turn to shear-impact disag-gregation. Impacting results in a heterogeneous distribution of granule velocities and a tendency of relative movement in agglomerates. Relative movement will bring about the stretch of liquid bridge between granules. If the maximum separation distance of wet granules exceeds the rupture distance of liquid bridge, disaggregation happens. The ruptures of liquid bridge start from impact point and expand to outward, from bottom to up, from inside to outside in coating agglomeration. It is found that the rupture of liquid bridge needs time for accumulation and goes through three stages termed as slow rupture stage, quick rupture stage and entire rupture stage. With the increase of impact velocity, par-ticle gravity, and rotating speed of core granules, disaggregation processes of wet granule agglomerates

  3. 产业集聚发展与环境污染关系的考察——来自中国制造业的证据%The exploration of the relationship between the industrial agglomeration' s developments and the environmental pollution the evidence from the manufacturing in China

    Institute of Scientific and Technical Information of China (English)

    闫逢柱; 苏李; 乔娟

    2011-01-01

    Along with the global environmental deterioration increasing and the industrial agglomeration research furthering, a few foreign scholars begins to pay attention to the relationship between industrial agglomeration and environmental pollution.Applying two digit - manufacturing classified data in China from 2003 to 2008.The paper explores such relationship by means of panel error correction model.The results show that the development of industrial agglomeration can help to reduce the environmental pollution in the short term.However, in the long term, the development of industrial agglomeration and the environmental pollution don't have inevitable cause - effect relationship.%随着全球环境恶化加剧和产业集聚研究的深入,国外少数学者开始关注产业集聚发展与环境污染之间的关系.基于此,运用2003-2008年中国制造业两位码的行业分类数据和面板误差修正模型实证考察了这一关系.结果发现,短期内产业集聚发展有利于降低环境污染,但长期内产业集聚发展与环境污染之间不具有必然的因果关系.

  4. 环鄱阳湖城市群产业升级与高等教育协调发展分析%An Analysis on the Industrial Upgrading and Coordinated Development of Higher Education in Urban Agglomeration around Poyang Lake

    Institute of Scientific and Technical Information of China (English)

    郭露; 戴志敏

    2016-01-01

    城市群作为区域经济的一个重要增长极,对周边其他地区具有巨大的辐射效应与带动作用。作为新生的中部城市群,关于环鄱阳湖城市群如何取得竞争优势,已成为理论研究者和政府决策者关注的热点问题。高等教育作为实现后发超越的重要力量对城市群持续发展起决定性作用。文章通过运用因子分析的方法对环鄱阳湖城市群的高等教育状况与城市群发展不同阶段进行比较、分析与评估。利用管理统计方法,探索高等教育的发展对环鄱阳湖城市群产业结构升级的促进作用,并提出了与之相关的建议。%Urban Agglomeration is an important regional economic growth pole,it has enormous and stimulating role of radiation effects on the surrounding region. As a new central urban agglomeration,how urban agglomeration around poyang Lake gain competitive advantage has become a hot issue which was concerned by theory researchers and government policy makers. As a realization of late-development advantage on strength,higher education plays a decisive role in sustainable urban agglomerations development. By using factor analysis method,this paper com-pares,analyzes and evaluates the urban agglomeration around poyang Lake’s higher education status and urban ag-glomeration development at different stages. By using management statistical methods,it explores the promoting effect of high education development to the industrial structure upgrading of urban agglomeration around poyang Lake,and puts forward the related and effective suggestions and policies.

  5. A Study of the Impact of Industrial Agglomeration Dominated by the Government on Regional Economic Growth .an Example of Industrial "Double Transfer" in Guangdong Province%政府主导下的产业集聚对区域经济增长的影响——以广东省“双转移”为例

    Institute of Scientific and Technical Information of China (English)

    李淑贞

    2012-01-01

    理论分析表明,产业集聚能促进区域经济增长。采用广东省承接产业转移的15个欠发达城市的相关统计数据,对产业集聚与区域经济增长之间的关系进行实证检验,结果表明:产业集聚与区域经济增长之间呈显著的正相关关系。据此,提出进一步发挥产业集聚效应的几点政策建议。%At present, Guangdong province is energetically carrying out the "double transfer" strategy, a- mong them, the industrial transfer has achieved remarkable results. Industrial agglomeration caused by the in- dustrial transfer, has increasingly become the focus of attention of academia and decision-making departments. Theoretical analysis shows that, industrial agglomeration can promote the regional economic growth. This pa- per makes an empirical test of the relationship between industrial agglomeration and regional economic growth,using relative statistic data of 15 less developed cities in Guangdong province which have been under- taking the industrial transfer. The results show that there is a significant positive correlation between industrial agglomeration and regional economic growth. Based on this, the paper puts forward some policy suggestions to further exert the industrial agglomeration effect.

  6. Experimental study on promotion of coal combustion fine particles acoustic agglomeration removal by using wetting agents%润湿剂促进燃煤细颗粒声波团聚脱除的实验研究

    Institute of Scientific and Technical Information of China (English)

    颜金培; 陈立奇; 杨林军

    2014-01-01

    在声波团聚室中研究了润湿剂液滴与细颗粒碰撞团聚脱除特性,提出了一种利用润湿剂促进细颗粒在声波场中捕集的新方法。结果表明,不同润湿剂溶液对细颗粒在声波场中的团聚脱除效果存在较大差异,采用 JFC 和 FS-310润湿剂溶液时,细颗粒分级脱除效率与采用水时的分级脱除效率相近。而 SDS 和 Silanol w22溶液,则可有效提高细颗粒在各粒径段的分级脱除效率。细颗粒在声波场中的脱除效率与润湿剂润湿性能具有很好的相关性,随润湿剂对细颗粒相对接触角增大而降低,在声压级为150 dB 时,相对接触角由83°降低到0°,细颗粒脱除效率提高了18%,在无声场作用下,脱除效率仅提高了5%。细颗粒脱除效率随声压级的增大而提高,在低声压级条件下,添加润湿剂可有效提高细颗粒脱除效率,声压级在130 dB时,添加 SDS 溶液液滴后细颗粒脱除效率比声场单独作用时的脱除效率提高了25%。表明添加润湿剂可有效提高细颗粒在声波场中的团聚脱除效率,实现在低声压级条件下,获得高的细颗粒脱除效率。%The characteristics of agglomeration removal between wetting agent droplets and fine particles wereinvestigated in an acoustic agglomeration chamber. A novel technique using wetting agents to promote the fine particle capture by acoustic agglomeration was presented. The experimental results show that the type of wetting agent has a significant effect on the acoustic agglomeration of fine particles. The particle stage removal efficiencies using JFC and FS-310 are similar to that using plain water droplets, but the removal efficiencies bySDS and Silanol w 22 are much higher than that using water droplets. Fine particle removal efficiency in the acoustic field correlates well with the wettability of wetting agents, which decreases with increasing the relativecontact angle of wetting agents

  7. Association between tuff diagenesis and mud cake to agglomerated cake(MTA)at cement-formation interface%固井二界面泥饼仿地成凝饼与凝灰岩成岩的关联性

    Institute of Scientific and Technical Information of China (English)

    顾军; 杨卫华; 张玉广; 高玉堂; 刘霞; 李天府

    2011-01-01

    In order to investigate the geologic diagenesis of mud cake to agglomerated cake ( MTA) at cement-formation interface, the analysis and testing technology such as X-ray diffraction ( XRD) , thermogravimetric analysis ( TG) , scanning electron microscope & EDX ( SEM & EDX) and X-ray fluorescence ( XRF) were used to study the association of MTA and diagenetic reaction of tuff volcanic process. The results show that. the effect of mud cake modifier in the MTA diagenetic reaction is similar to that of pyroclastic material in the tuff diagenetic reaction, and the phases and chemical compositions are basically consistent. The forming agent of agglomerated cake is similar to the fluid of diagenetic reaction of tuff volcanic process. so the velocity of diagenetic reaction can be accelerated and the reaction products can be controlled, too. The characteristic diagenetic phenomenon and reaction products of the two are siruilar, and the crystallization phenomenon of FeS2 Occurred in both, which is a kind of rubbish mineral. The silicon content and aluminum content in the agglomerated cake decreased while the calcium content increased with time. The curing reaction process of MTA is consistent with alkali-activated pozzolanic materials chemical reaction model, in which the chemical reaction model is dealuminization, junction silicon and calcium absorption.%为了解固井二界面泥饼仿地成凝饼(MTA)的地质成岩作用,采用XRD,TG,SEM+EDX和XRF荧光分析测试技术对MTA与凝灰岩火山沉积作用成岩反应的关联性进行研究.结果表明:泥饼改性剂在MTA成岩反应中所起的作用与火山碎屑物质在凝灰岩成岩反应中所起的作用相类似,且物相和化学组成基本一致;凝饼形成剂将凝灰岩火山沉积作用成岩流体的缓慢形成过程直接化为一种现存成岩流体,加快了成岩反应速度,控制了反应产物的类型,二者的特征成岩现象和反应产物均有相似性,且均存在FeS:垃圾矿物

  8. Coordination Development of New-type Urbanization in Chengdu-Chongqing Urban Agglomeration%成渝城市群新型城镇化发展协调性研究

    Institute of Scientific and Technical Information of China (English)

    李剑波; 李纯锴

    2016-01-01

    新型城镇化是人口、土地、经济、生态、社会5大城镇化子系统的协调推进,运用协调度模型、探索性空间数据分析和障碍度模型,判别成渝城市群城镇化发展的协调性。结果表明:成渝城市群城镇化综合水平整体不高,其均值和标准差随时间增大,各区域间差异显著;子系统的发展在空间上呈现非均衡性特征,人口城镇化分异程度始终最高但空间分异不断缩小,社会和经济城镇化的空间分异逐渐增大,土地和生态城镇化的空间分异不断缩小。成渝城市群城镇化协调度总体呈现递增态势,空间分异特征较明显但不断缩小;城镇化协调度相似地区在空间上呈现强集聚状态,成都市、德阳市、眉山市、南川区、綦江区始终为热点区域,渝东及渝东南始终为冷点区域,热点区和冷点区比重逐渐增加。%New-type urbanization is the coordinate of population, land, economic, ecological and social subsystem of urbanization.Using the coordination degree model, exploratory spatial data analysis and the disorder degree model, discriminant Chengdu-Chongqing urban agglomera-tion of urbanization development coordination.The results showed that, the level of urbanization among Chengdu-Chongqing urban agglomera-tion was not too high, mean and standard deviation of urbanization level increases with time and the spatial difference was significant .The de-velopment of urbanization subsystem was non-equilibrium.The spatial difference of demographic urbanizationis was always highest but shrink-ing, and the spatial difference of economic urbanization and social urbanization increase gradually, the spatial difference of land urbanization and ecological urbani-zation keeps reducing.The coordination degree of urbanization in Chengdu-Chongqing urban agglomeration keeps in-creasing, spatial variation was obvious but shrinking.The similar region of urbanization coordination

  9. 液相水解法制备高纯石英粉体团聚状态的控制%Control of the Agglomerates During the Preparation of Quartz Powder by Aqueous Solution Hydrolysis Method

    Institute of Scientific and Technical Information of China (English)

    聂兰舰; 王玉芬; 向在奎; 宋学富; 饶传东

    2011-01-01

    High purity synthetic quartz powder was prepared by hydrolysis of silicon tetrachloride obtained from the byproduct of polysilicon production.The formation mechanisms and control technology of synthetic silica-particle aggregates during the process of hydrolysis reaction, drying, and calcination were analyzed by using laser particle size analyzer and SEM.And the structure morphology and hydroxyl content of synthetic quartz powder were characterized by XRD and IR spectrometer(IR).The experimental results show that adding PEG or CTAB in the hydrolysis reaction of SiCl4 would prevent agglomeration of silica-particle.Washing the hydrolysate with deionized water and then ethanol dehydration before drying can reduce agglomeration of powder.Drying temperature should not be too high, and it is the best to make moisture even spilling of silica powder.With the heat treated temperatures increasing, the hydroxyl content of silica powder gradually decreases, and the silica powder is gradually transforming non crystal to alpha-cristobalite after sintering in 1 250 ℃, XRD peaks become sharper and stronger at 1 300 ℃.But it would cause robust neckformation of silica-particle under high temperature, and there are hard particle agglomerates in the powders.,So it needs to grind and screen to obtain synthetic quartz powder of proper particle size.%采用多晶硅副产物SiCl4液相水解法制备高纯合成石英粉,通过激光粒度分析、SEM等研究了水解反应、干燥、高温煅烧过程中粉体颗粒团聚体的形成机理及控制技术,并利用XRD和IR分析了合成石英粉的结构形态及羟基含量.结果表明:在水解反应过程中,添加合适分散剂(如聚乙二醇、十六烷基三甲基溴化铵)有助于防止水解产物SiO2颗粒的团聚;在干燥前,用去离子水洗涤水解产物多次后再用无水乙醇脱水,可减少干燥过程颗粒的团聚;干燥温度不宜过高,以水分易于均匀地排除即可;随着烧结温度的升

  10. 中国蔬菜生产空间集聚演变、机制、效应及政策应对%Spatial Evolution, Mechanism, Effect and Policies of Vegetable Production Agglomeration in China

    Institute of Scientific and Technical Information of China (English)

    吴建寨; 沈辰; 王盛威; 张建华; 孔繁涛

    2015-01-01

    并且具有较高的解释水平,基尼系数在10%的显著性水平下通过了t检验,它每提高1个百分点,蔬菜单位面积产值将增加2.48个百分点。【结论】1995—2012年,中国蔬菜生产东、西部产量差距梯度明显减弱,生产重心向北方发生转移,空间分布特征变化明显,尤其在前期更具波动性;蔬菜生产空间聚集对蔬菜产值影响显著,集聚的加强可有效促进蔬菜产值的增加;基于优化蔬菜生产空间格局角度,未来应从加强主产区建设、推进规模化与专业化生产、注重产业各环节间协同入手,促进产业健康发展。%[Objective]In recent years, vegetable supply and demand pattern characterized by“large market, great circulation”has been basically formed in China. And the change of the spatial agglomeration in vegetable industry is remarkable. In this paper, the characteristics, effects, and mechanism of the spatial agglomeration evolution in China’s vegetable production from 1995 to 2012 were systematically discussed by taking 31 provinces (cities) as research units, and the policy suggestions were also proposed. This research will provide a support for optimizing production arrangement and ensuring effective supply. [Method] The share of n largest provinces (cities) in total production was calculated based on the index of concentration ratio. In order to reveal the characteristics of spatial agglomeration in vegetable production industry from 1995 to 2012, the spatial concentration on provincial level was measured by using Gini coefficient model. To show the effect of production agglomeration on vegetable industry development, the model based on modified Cobb-Douglas production function was built to analyze the significance of the inputs such as vegetable production agglomeration level, vegetable price, labor per unit, and investment per unit. [Result]The characteristic of China’s vegetable production spatial distribution

  11. 低碳约束对产业集聚的门槛效应分析--基于国内省际面板数据%The Threshold Effect of Low Carbon Constraints on Industrial Agglomeration---An Empirical Analysis of the Provincial Panel Data in China

    Institute of Scientific and Technical Information of China (English)

    刘辉煌; 汤玲

    2016-01-01

    As an important form of industrial organization ,industrial agglomeration has always been the focus of theoretical research ,but few scholars directly study the impact of low carbon constraints on industrial agglomeration .For this rea‐son ,we choose the industrial data of China's 30 provinces during 2000 -2012 ,using threshold regression method ,and from two angles of per capita income and human capital ,testing threshold effects of carbon constraints on industrial agglomera‐tion .Income threshold test show s that in middle‐income and low‐income phase ,low carbon constraints inhibiting agglom‐eration .And in the phase of high‐income ,low carbon constraint significantly increased area industrial agglomeration ;hu‐man capital threshold test show s that at the stage of high human capital ,low carbon constraint can significantly promote the regional industrial agglomeration ,how ever ,the effect is opposite in low and middle human capital stage .Limited by regional average income and human capital level ,the government implement low carbon constraints now will have a nega‐tive impact on industrial agglomeration .Therefore ,accelerating the local economic development ,enhancing the level of human capital ,and promoting low‐carbon technology innovation is the main direction of industrial agglomeration in the fu‐ture .%产业集聚作为重要的产业组织形式,其影响因素一直是理论界研究的重点,但鲜有学者直接研究低碳约束对产业集聚的影响。基于2000-2012年中国内地30个省(市、自治区)的数据,利用门槛回归方法,从人均收入和人力资本两个角度,检验了低碳约束对产业集聚的门槛效应。收入门槛的检验结果表明,在中、低收入阶段,低碳约束抑制产业集聚,而在高收入阶段,低碳约束则显著促进地区产业集聚;人力资本门槛的检验结果表明,在高人力资本阶段,低碳约束能够显著带动地区产业

  12. 区域旅游产业集聚化转型升级发展路径及其动力机制研究%On the Development Path of the Transformation and Upgrading of Regional Tourism Industrial Agglomeration and its Dynamic Mechanism

    Institute of Scientific and Technical Information of China (English)

    刘少和; 桂拉旦

    2014-01-01

    工业化、城市化推动了大众休闲、大众旅游规模化市场形成,从而促进了旅游产业集聚化发展。基于产业集聚理论,对旅游产业集聚路径与动力进行规范分析和经验总结,发现旅游产业集聚除受到产业集聚成本-效益机制约束之外,还明显受到核心旅游品牌溢出效应的影响,形成品牌形象吸引-集聚机制与品牌价值延伸-溢价机制。在此动力机制作用下,区域旅游产业集聚化转型升级经历了基于核心旅游资源的资源组合集聚(景区组团式集聚)到基于度假住宿接待的要素配合集聚(要素配套式集聚),再到基于产业链延伸的产业融合集聚(产业集群式集聚)等三个阶段,推动旅游产业集聚业态从“资源景区组团区”到“度假游憩综合体”再到“旅游产业园区”发展,从而推动旅游业转型升级。%With the development of industrialization and urbanization, tourism markets of mass recreation and tourism emerge on a large scale, which promotes the development of tourism industrial agglomeration. Analyses and experience indicate that tourism industrial agglomeration is restricted by the cost-effectiveness mechanism of it, and it is also affected obviously by the effect of core tourism brand. The transformation and upgrading of re⁃gional tourism industry agglomeration firstly bases on the resource agglomeration of core tourism resources, then on the element agglomeration of vacation tour accommodation, last on the industry integration agglomeration of industry chain extension. The three stages illustrate the transformation and upgrading of tourism.

  13. Effect of biomass-sulfur interaction on ash composition and agglomeration for the co-combustion of high-sulfur lignite coals and olive cake in a circulating fluidized bed combustor.

    Science.gov (United States)

    Varol, Murat; Atimtay, Aysel T

    2015-12-01

    This study aimed to investigate the effect of biomass-sulfur interaction on ash composition and agglomeration for the co-combustion of high-sulfur lignite coals and olive cake in a circulating fluidized bed combustor. The tests included co-combustion of 50-50% by wt. mixtures of Bursa-Orhaneli lignite+olive cake and Denizli-Kale lignite+olive cake, with and without limestone addition. Ash samples were subjected to XRF, XRD and SEM/EDS analyses. While MgO was high in the bottom ash for Bursa-Orhaneli lignite and olive cake mixture, Al2O3 was high for Denizli-Kale lignite and olive cake mixture. Due to high Al2O3 content, Muscovite was the dominant phase in the bottom ash of Denizli Kale. CaO in the bottom ash has increased for both fuel mixtures due to limestone addition. K was in Arcanite phase in the co-combustion test of Bursa/Orhaneli lignite and olive cake, however, it mostly appeared in Potassium Calcium Sulfate phase with limestone addition.

  14. The study of high temperature disaster risk zoning in Beij ing-Tianj in-Hebei urban agglomeration%京津冀城市群高温灾害风险区划研究

    Institute of Scientific and Technical Information of China (English)

    杜吴鹏; 权维俊; 轩春怡; 房小怡; 郭文利

    2014-01-01

    本文利用175个气象站观测数据和社会经济资料,从致灾因子、孕灾环境、承灾体、抗灾能力四个方面研究了京津冀城市群高温灾害风险,结果表明:京津冀城市群高温频次呈南部高、北部低以及平原地区高、山区低的空间分布特征,频次最高区域位于石家庄和衡水以南、邯郸以北地区,北部的承德、张家口和秦皇岛地区高温频次最低;致灾因子高危险区和孕灾环境高敏感区主要分布在河北省南部,承灾体高易损区主要位于大型城市,经济发达的城区抗灾能力较强,抗灾能力风险较低;京津冀城市群高温灾害综合风险区划呈南高北低特征,高风险区集中在河北中南部及北京和天津的市区,河北中部及邻近北京、天津地区则为次高风险区和中等风险区,河北北部、西北部和东北部多为低风险区和较低风险区。%In recent years,climate change has become a hot topic and which was being researched by many atmospheric scientists.Meanwhile,climate change has caused many extreme weather and climate events,such as the high temperature disaster,which was increasing obviously and could lead to adverse impacts on urban safety, economic development and human health.Therefore,carrying out the risk zoning research is becoming more and more important and indispensable.Beijing-Tianjin-Hebei urban agglomeration is one of the most important regions in China,where often affected by meteorological disaster,especially summer high temperature and hot wave.In this paper,we use the data of 175 meteorological observations and socio-economic material to research and analyze the high temperature disaster risk in Beijing-Tianjin-Hebei urban agglomeration.Results show that:the high temperature frequency is higher in the south and plains,while it is lower in the north and mountains.The area between Shijiazhuang,Hengshui and Handan has the highest frequency.However,in the

  15. 西安市生产者服务业空间布局特征与集聚模式研究%Spatial Features and Agglomeration of Producer Services in Xi'an City, China

    Institute of Scientific and Technical Information of China (English)

    薛东前; 石宁; 公晓晓

    2011-01-01

    phase. Xi'an has tremendous demand for producer service industry and also has good foundation for developing producer services. The research on the present developing condition and spatial distribution features of Xi'an City's producer service industry contributes to the development of manufacturing industry and industrial structure upgrade. It can effectively affect spatial pattern of the city and reconstruction at the same time. With the development of the world economy, producer services separated from manufacturing and have become the main force to help manufacturing upgrade and industrial structure change instead of traditional consumer services. This paper, taking Xi'an as an example, according to correlation theory of industrial economics, regional economics, economic geography and urban geography, based on industry statistics of producer services in "Xi 'an Statistical Yearbook" ( 1998-2010 ) and related enterprise information in "Xi 'an Yellow Pages" (2002, 2008 ) and by using methods of qualitative and quantitative analysis, statistic analysis and dynamic analysis and the software of ArcGIS, studies the development condition based on the proportion of gross production value of producer services,,number of employed persons of producer services in tertiary industry, and spatial distribution characters of producer services. The results show that spatial distribution of producer service presents relative low agglomeration degree at present, but has agglomeration trend, and producer services by sector have diverse agglomerate degrees. The overall producer services industry presents multi-core agglomerate pattern. This study has an important practical significance for upgrading of industrial structure, the determination of reasonable industrial development direction and reasonable planning of urban industrial spatial distribution, and the promotion of economic growth and urban competitiveness in Xi'an.

  16. Locative Factors Comparative Preferences and Producer Service Industrial Agglomerations: A Simulative Analysis of Finance and Software Industries%区位因素比较偏好与生产性服务业集聚——以金融和软件业为例的模拟分析

    Institute of Scientific and Technical Information of China (English)

    刘刚; 黄炎

    2013-01-01

    针对不同生产性服务行业所表现出的集聚区位差异,以金融、软件业为例,构建两种不同的区位因素比较偏好规则,采用基于Agent的建模方法和含权的复杂网络平均集聚系数、平均最短路径长度参数,分别度量集聚规模和程度,对金融业、软件业集聚进行模拟和案例分析.结果表明:金融业、软件业集聚规模仅与区位因素比较偏好密切相关,而集聚程度与区位因素比较偏好、不同偏好下的区位因素变化有关.%Aiming at the locative differences of different production service industrial agglomerations, finance and software industries are taken as examples, and computer simulation and case analysis of their agglomeration scales and closeness are performed based on agent modeling and a weighted complex network average clustering coefficient and average shortest path length by considering two different comparative preference principles of locative factors. The results show that, the scales of finance and software industrial agglomerations are related to the comparative preferences to communication or professional personal densities in a region, the closeness of finance and software industrial agglomerations are concerned with comparative preferences and changes of the locative factors.

  17. 我国高技术产业空间集聚及影响因素研究--基于省级面板数据的空间计量分析%Study on China's High-Tech Spatial Agglomeration and Its Determinants:Based on the Spatial Econometric Analysis of Provincial Panel Data

    Institute of Scientific and Technical Information of China (English)

    金春雨; 王伟强

    2015-01-01

    从空间计量经济视角对高技术产业空间集聚及影响因素进行实证分析,研究结果表明:我国高技术产业呈现出明显的空间集聚特征,区域间产业集聚存在正向的空间相关性。人力资本、规模经济、运输成本及基础设施都对本地区高技术产业集聚发展具有显著的正向影响;知识溢出、市场规模和FDI的影响系数都显著为负。相邻地区的知识溢出和市场规模都对本地区高技术产业集聚发展造成了抑制作用;而对对外贸易产生了促进效应。%From the perspective of spatial econometrics, this paper analyzes the high-tech industrial agglomeration of China and its influencing factors. The empirical results show that the development of high-tech industrial ag-glomeration has a significantly positive spatial autocorrelation among the provinces in China. Human capital, scale economies, transportation costs and urban infrastructure are conducive to the development of provincial high-tech industrial agglomeration; and knowledge spillovers, market demand and FDI have a negative impact on the high-tech industrial agglomeration's development. The impact of knowledge spillovers and market demand from neighboring provinces are significantly negative, and the impact of international trade is significantly positive.

  18. Agglomeration removal of fine particles at super-saturation steam by using acoustic wave%燃煤细颗粒在过饱和氛围下声波团聚脱除的实验研究

    Institute of Scientific and Technical Information of China (English)

    颜金培; 陈立奇; 杨林军

    2014-01-01

    An experimental installation was set up for investigating experimentally agglomeration removal of dust particles under various steam super-saturation degrees by using acoustic wave. The results show that the acoustic wave entrainment coefficient for these fine particles goes up with increase of the super-saturation degree, leading to improvement of the removal efficiencies. When the super-saturation degree is below 1.0,the total removal efficiency of dust particles has almost no increase with it, and is quite low, about 10%. However, when the super-saturation degree is bigger than 1.0, the total efficiency can be promoted and goes up rapidly with the increase of super-saturation degree. For example, when the super-saturation degree increases from 1.0 to 1.5, the removal efficiency rises about 50%. The removal efficiency of dust particles increases also with rising sound pressure level. Even if at high sound pressure steam condensational growth can not occur yet at 0.3 of low steam super-saturation degree, hence, only low removal efficiency, less than 20%, is observed. But at 1.2 of high steam super-saturation degree, the removal efficiency can be significantly improved, for example at 130dB of lower sound pressure level, about 70% high efficiency can be obtained. These facts indicate that removal of dust particles can be effectively improved if acoustic wave is used, i.e. their agglomeration with steam can be enlarged.%在不同过饱和氛围下,建立了燃煤细颗粒在声波场中团聚长大脱除的实验装置,对细颗粒物在声波场和不同过饱和氛围下的团聚长大脱除特性进行了实验研究。结果表明:细颗粒在声波场中的夹带系数随过饱和度的增大而增加,相应的脱除效率也有所提高;在过饱和度低于1.0时,细颗粒的总脱除效率很低(约为10%),且几乎不随过饱和度的增大而增加,而当过饱和度大于1.0后,细颗粒的脱除效率随过饱和度的增大而

  19. 长江三角洲秋季热岛特征及演变分析%Characteristics Analysis on Heat Island Effect in Yangtze Delta Urban Agglomeration in Autumn

    Institute of Scientific and Technical Information of China (English)

    刘会芬; 杨英宝; 王帆; 潘鑫

    2012-01-01

    With the rapidly increasing of economy in the Yangtse Delta, the acceleration of resources consump-ing and the exacerbation of environment pollution phenomenon are increasing. Thus, the bottleneck of environment has becoming prominent. The characteristics on heat island effect are analyzed in Geographical Yangtze Delta Urban Agglomeration based on MODIS land surface temperature products. The results show that, after a decade of change, the distribution characteristics shows offseting to the southeast and heat island intensity shows an overall increasing trend. The heat islands are arranged clearly in "Z" distribution in 2010. At the same time, the inner-annual variation of the heat island intensity was analyzed in Nanjing, Shanghai, Hangzhou. The characteristics of the high temperature zone is expressed as a way of making a pie, that is expending the main city to the rim.%近年来,伴随着长三角地区经济快速增长,区域资源消耗加速和环境污染加剧现象突出,环境瓶颈日益凸显.利用MODIS陆地温度产品对地理带上的长江三角洲区域的城市群的城市热岛特征及演变进行研究.结果表明,经过十年的变迁,热岛分布向东南方向偏移;热岛强度总体呈现增强趋势.2010年呈现出清晰的“Z”字型分布.同时重点分析了南京、上海、杭州这几个大城市热岛强度的年际变化,其高温区的特征,均表现为“摊饼状”,即以主城区为中心向周边扩展.

  20. The Evaluation on Tourism Sustainable Development in Changsha-Zhuzhou-Xiangtan Urban Agglomeration%长株潭城市群旅游可持续发展评价研究

    Institute of Scientific and Technical Information of China (English)

    周志宏

    2012-01-01

    长株潭城市群“两型社会”建设要求该地区的旅游发展具有可持续性,结合长株潭城市群旅游系统的特征构建了该区域旅游的可持续发展水平评价指标体系,并利用层次分析对各项指标赋权,采用综合指数法评价了该地区旅游的可持续发展水平.结果显示:长株潭城市群旅游的总体可持续发展水平较强.这一方面说明长株潭城市群自开展“两型社会”建设以来在旅游可持续发展方面取得了较好的成效;另一方面又要求政府加大建设与管理,促使该地区旅游可持续发展水平向更高层次推进.%The "two-oriented society" construction in Changsha-Zhuzhou-Xiangtan urban agglomeration requires its tourism develop sustainably. This paper builtted the index system of tourism sustainable development with its own characteristic in this area, weighted every index with analytic hierarchy process, and assessed the sustainable development level of tourism by using the synthetically index method. The results showed that the sustainable development level of tourism in this area was high. Therefore, it concluded that great achievement on tourism in this area has obtained for the past few years, moreover, it called for the government to increase the construction and management to promote better development.

  1. 改善天然湿型砂混砂过程中结团现象的研究%Study on the Agglomeration in the Process of Natural Green Sand Mixing

    Institute of Scientific and Technical Information of China (English)

    高远; 朱世根; 骆祎岚; 桑小龙

    2012-01-01

    The agglomeration occurring in the green sand mixing was effectively reduced by adding an additive YZ-1 and changing the watering sequence.The results indicate that the compression strength of green sand increased with the increasing of addition YZ-1 lubricant when the addition amount is less critical value; with the increase of YZ-1 lubricant, the compression strength reaches a peak value, then the compression strength decreases till cannot satisfy requirement of mold making.By adding YZ-1 lubricant and changing the watering sequence, the cluster phenomenon can be solved better.%通过加入YZ-1型润滑剂和改变加水顺序等措施,可以有效改善湿型砂混砂过程中的结团现象.当YZ-1型润滑剂加入量比较少时,可以在一定程度上提高湿型砂的抗压强度;当YZ-1型润滑剂含量继续增加时,湿型砂抗压强度又会逐渐降低直至无法造型.采用原砂先加水后加粘土的工艺比传统的原砂先加土后加水的工艺,型砂的强度更高、结团度更低.对加过YZ-1型润滑剂的湿型砂再重新混制反复多次,抗压强度提高,结团度基本不变.

  2. Research on the Integration of Tourism Product Development of the Wuhan Urban Agglomeration%武汉城市圈旅游产品开发一体化研究

    Institute of Scientific and Technical Information of China (English)

    梁滨

    2012-01-01

    武汉城市圈旅游产品开发存在着无序开发、重复建设、各自为阵、结构单一、通达性差及旅游商品开发不足等问题,本文据此提出了"互惠互利,整合多赢"、"差别战略,优势互补"等六大一体化开发战略思路,并提出了横向联合、纵向组合及分区布局等布局方案及对策。串联型、组合型、结构型及精品型旅游线路组织体现了旅游线路设计一体化的核心思想即线路互联对接。在旅游产品开发一体化研究中,也要关注旅游商品开发的一体化进程。%There are many problems in the development of the Wuhan Urban Agglomeration such as disordered development,repeated construction,poor accessibility,single structure and deficiency in the development of tourist commodities.This paper puts forward six tactic thoughts including reciprocity and mutual benefit,integration and multi-win,difference stratagem and complementary advantages,etc.And it brings forward those schemes and countermeasures such as horizontal integration, longitudinal combination and zoning distribution.Organizing of tourist line is propitious to the integration of its design.

  3. 集聚经济、空间依赖与中小企业发展空间差异%Agglomeration Economy, Spatial Dependence and Regional Disparity of Development of SMEs

    Institute of Scientific and Technical Information of China (English)

    高丽娜; 蒋伏心

    2013-01-01

      目前,我国中小企业发展存在明显的空间差异,由东至西形成了较为典型的圈层式空间结构。本文以我国中小企业发展空间差异特征分析为起点,定量考察其发展空间差异的影响因素。结果表明:除要素禀赋、运输成本、区域开放度、政府作用力有显著影响外,集聚经济、空间依赖对我国中小企业发展空间差异的形成具有重要作用。因此,应从城市集群发展、创造要素自由流动的市场环境,及完善区际交通网络等方面,重塑我国中小企业区域协调发展环境。%  Development of SMEs in China shows significant spatial differences , forming typical spherical type space structure from east to west .This paper takes the differences in development characteristics of SMEs as a starting point and analyzes quantificationally the influence factors .The results show that , in addition to factor endowments , transporta-tion costs , regional openness , government forces have a significant impact , agglomeration economy , spatial dependence have a significant impact on the formation of spatial development differences of SMEs .We should shape the regional envi-ronment for the coordinated development of SMEs from the aspects of the cluster development of city , creating the market environment for free movement of factors and improving interregional transportation system .

  4. 中国旅游产业集聚与旅游经济增长关系的空间计量分析%Spatial Econometric Research on the Relationship between Tourism Industry Agglomeration and Tourism Economic Growth in China

    Institute of Scientific and Technical Information of China (English)

    刘佳; 赵金金; 张广海

    2013-01-01

    Based on the research perspective of spatial econometrics, The paper uses the global spatial autocorrelation Moran's I index, and local indicators of spatial association, to investigate spatial correlation of tourism industry agglomeration and tourism economic growth about 31 provincial areas in Chinese mainland, it constructs a spatial econometric model of tourism industry agglomeration and regional tourism economic growth, to analyze theoretically and test empirically the relationship between tourism industry agglomeration and tourism economic growth of China. The research shows that, the development of tourism industry in China has been accompanied by the process of spatial agglomeration; tourism economic growth has the significant and positive spatial correlation, and it forms a gathering area of tourism economic activities in the eastern region; Meanwhile, tourism industry agglomeration has significant and positive impact on regional tourism economic growth, and it performs remarkable spatial spillover effects, so it causes spatial inequality of tourism economic growth.%基于空间计量经济学的研究视角,运用全局空间自相关Moran's I指数、空间关联局域指标LISA分析,考察中国大陆31个省级区域旅游产业集聚与旅游经济增长的空间相关,构建旅游产业集聚与区域旅游经济增长的空间计量经济模型,对中国旅游产业集聚与旅游经济增长的关系进行理论分析和实证检验.研究表明:中国旅游产业发展一直伴随空间集聚的过程,旅游经济增长存在显著的正向空间相关性,且在东部地区形成了旅游经济活动的集聚区:旅游产业集聚对区域旅游经济增长有显著的正向影响,并表现为较强的空间溢出效应,但这种溢出效应表现为显著的局部性特征,由此引起中国旅游经济增长的空间不均衡.

  5. Analysis of Knowledge Spillover Effect from the Perspective of Manufacturing Agglomeration and R&D Investment%知识溢出效应分析——基于制造业集聚与R&D投入的视角研究

    Institute of Scientific and Technical Information of China (English)

    刘斯敖; 柴春来

    2011-01-01

    An analysis model of manufacturing agglomerations, R&D investment and knowledge spillovers is constructed based on 1990-2008 provincial spatial panel data. It is found out that both manufacturing agglomerations and R&D investment have significant knowledge spatial spillovers. Industrial agglomerations in different ways have different effects of knowledge spillovers. Professional agglomerations are more conducive to regional economic growth but not conducive to regional innovation. Diversified industrial agglomeration is not conducive to regional economic growth but more conducive to regional innovation. R&D capital investment and regional human capital affect regional economic growth and innovation notably. The effect of social distance and technology gap is not significant on regional economic growth in China. Furthermore, an open society is favorable for knowledge spillovers and digestion, absorption and innovation while technology gap hinders regional innovation. Finally, the paper provides recommendations for drafting of policies by different regions.%本文以1990-2008年的省域空间面板数据,构建了我国制造业集聚、R&D投入与知识溢出效应分析模型.研究发现,制造业集聚与R&D投入存在显著的知识空间溢出效应,不同的产业集聚方式的知识溢出效应不同,专业化集聚比较有利于区域经济增长,但是不利于区域创新,而多样化的产业集聚不利于区域经济增长,但更有利于区域创新.R&D资本投入和区域人力资本对区域经济增长与创新的影响较大,而R&D人员投入-产出绩效低下.社会距离与技术距离对我国区域经济增长影响并不显著,但是开放的社会更有利于知识溢出与消化、吸收及创新,而技术差距阻碍了区域创新.最后,本文给出相应的区域发展政策建议.

  6. 武汉城市圈城镇化与土地生态系统服务价值空间相关特征%Spatial correlation characteristics of urbanization and land ecosystem service value in Wuhan Urban Agglomeration

    Institute of Scientific and Technical Information of China (English)

    姚小薇; 曾杰; 李旺君

    2015-01-01

    为促进新型城镇化进程下区域生态环境质量提升和土地资源可持续利用,该文基于武汉城市圈2010年土地利用数据,计算不同地域空间的生态系统服务价值;运用空间计量方法,分析研究区人口城镇化、空间城镇化、经济城镇化、生活城镇化和生态系统服务价值的空间分异特征,进而运用双变量空间自相关分析探讨不同城镇化水平对生态系统服务价值空间分异的影响。结果显示:除经济城镇化外,人口城镇化、空间城镇化和生活城镇化均与生态服务价值存在空间负相关关系,其中人口城镇化与生态服务价值的空间负相关性较强,其次分别为空间城镇化和生活城镇化。具体的,空间城镇化和生活城镇化与原材料生产价值之间的负相关性最强,人口、空间和生活城镇化与大气调节和保持土壤之间也分别存在明显的负相关性。不同城镇化水平与生态服务价值的双变量LISA图也具有相似的空间特征,高-低聚集区多分布于武汉城市圈经济水平相对发达的中部地区,而低-高聚集区主要分布在南部幕阜山区和北部的大别山一带。该研究能够为区域新型城镇化建设和生态环境管护提供决策参考。%As one of the largest developing countries in the world, China has entered an accelerating period of urbanization with significant growth of economy and population. However, the ecological and environmental issues have directly threatened the sustainability of social and economic development in the country. In order to promote ecosystem quality in the high-speed urbanization process as well as provide scientific and feasible basis for differentiated and sustainable land use, this paper tried to explore the spatial correlation between urbanization and ecosystem service value (ESV). In the research, a metropolitan region in Central China called Wuhan Urban Agglomeration was selected

  7. The Driving Factors and the Action Path of the Regional Space of the Production Service Industry Agglomeration%生产性服务业集聚重构区域空间的驱动因素及作用路径

    Institute of Scientific and Technical Information of China (English)

    韩锋; 张永庆; 田家林

    2015-01-01

    AS our country economy form gradually from the production of goods towards production services , the rapid development of the productive service industry for economic and social development to support and promote the role in an increasing highlight ,the pro-ductive service industry in industrial integration , employment , stable growth has become competition of industry of our country . The strate-gic commanding point and the industrial structure continuously optimize the key power . Producer service industry clusters in the evolution of regional economic development and geographical space plays a huge role in agglomeration and producer services agglomeration effects bring industrial space layout of the reconstruction and regional industrial restructuring , traffic network planning and layout optimization and trans-formation of living space and urban land use types of change and core functional area pattern transfer , the rapid development of productive service industry and cluster agglomeration has become driving force of regional economic space reconstruction strategy to achieve .Producer services agglomeration regional spatial restructuring of the driving factors and path analysis based on the research of new economic geography agglomeration effect on regional economic structure and industry fusion , and space reconstruction evolution mode is of great significance ,to drive factors and the role of path as starting point to research the productive service industry agglomeration reconstruction of the regional space can be in-depth study of agglomeration on regional economic development and regional spatial geographic influence and radiation .%随着我国的经济形态逐步由商品生产迈向服务生产,高速发展的生产性服务业对于经济社会发展的支撑和推动作用日益彰显,生产性服务业在产业融合、吸纳就业、稳定增长等方面发挥重要作用,已经成为我国产业竞争的战略制高点及产业结构不

  8. Agglomeration-Free Distributor for Fluidized Beds

    Science.gov (United States)

    Ouyang, F.; Sinica, A.; Levenspiel, O.

    1986-01-01

    New gas distributor for fluidized beds prevents hot particles from reacting on it and forming hard crust. In reduction of iron ore in fluidized bed, ore particles do not sinter on distributor and perhaps clog it or otherwise interfere with gas flow. Distributor also relatively cool. In fluidized-bed production of silicon, inflowing silane does not decompose until within bed of hot silicon particles and deposits on them. Plates of spiral distributor arranged to direct incoming gas into spiral flow. Turbulence in flow reduces frequency of contact between fluidized-bed particles and distributor.

  9. Breakage of Agglomerates: Attrition, Abrasion and Compression

    NARCIS (Netherlands)

    Van Laarhoven, B.

    2010-01-01

    In many industries particulate solids are handled in different forms. When producing particles breakage is an important wanted, in the case of grinding, or unwanted phenomenon. Granules often consist of more than one component and multiple phases. This means that granules are strongly anisotropic an

  10. Agglomeration in fluidized beds: detection and counteraction

    NARCIS (Netherlands)

    Bartels. M.

    2008-01-01

    Fluidized beds comprise a quantity of solid particles that is suspended by an upward flowing gas. They are used for a variety of processes in the chemical industry, such as catalytic reactions, drying, coating and energy conversion. A major problem in industrial practice is the occurrence of unwante

  11. The Research about the Shaanxi Province High-tech Zone’s Industry Agglomeration and Technology Spillovers of FDI--An Empirical Analysis Based on 3 High-tech Zones’ Panel Data%陕西省高新区产业集聚与FDI技术溢出效应研究--基于三个高新区面板数据的实证分析

    Institute of Scientific and Technical Information of China (English)

    王利晓

    2015-01-01

    利用2007-2012年陕西省三个国家级高新区及城市面板数据,将产业集聚与FDI纳入同一经济计量模型,研究高新区产业集聚、FDI技术溢出对城市经济增长的影响,验证产业集聚与FDI技术溢出的交互影响作用。结果表明:产业集聚弹性为0.2307,显著正向促进高新区所在城市经济增长;交互作用下,除劳动投入在5%统计水平上正向显著外,资本投入、产业集聚、产业集聚与FDI交互项均在1%统计水平上正向显著;高新区产业集聚与FDI技术溢出相互促进共同显著促进了城市经济增长与技术进步。%Based On the 3 high-tech zones’ panel data of Shaanxi Province from 2007 to 2012,this paper puts Industry Agglomeration with the FDI into the same econometric model,researches the impact of high-tech zone’s industry Agglomeration and Technology Spillovers of FDI on city economic growth,and verifies the inter⁃action of the Industry Agglomeration and FDI. The empirical analysis indicates Industry Agglomeration promotes economic growth significantly,the marginal effect of industrial agglomeration to city economic growth is 0.2307, which is larger than the other factor input. Under the interaction capital investment,industrial agglomeration,in⁃dustrial agglomeration and FDI’ s interaction are one percent statistical level significantly positive but the labor input is five percent statistical level significantly positive to city economic growth;high-tech zone industrial ag⁃glomeration and FDI technology spillover are in mutual promotion,and they commonly promotes the city econom⁃ic growth .

  12. Impacts of anthropogenic pressures on the water quality of the Gironde Estuary (SW France) from the Urban Agglomeration of Bordeaux: spatial characterization and inputs of trace metal elements (Ag, As, Cd, Cu, Pb and Zn)

    Science.gov (United States)

    Kessaci, Kahina; Coynel, Alexandra; Blanc, Gérard; Deycard, Victoria N.; Derriennic, Hervé; Schäfer, Jörg

    2014-05-01

    Recent European legislation (2000/60/CE) has listed eight trace metal elements as priority toxic substances for water quality. Urban metal inputs into hydrosystems are of increasing interest to both scientists and managers facing restrictive environmental protection policies, population increase and changing metal applications. The Gironde Estuary (SW France; 625 km2) is known for its metal/metalloid pollution originating from industrial (e.g. Cd, Zn, Cu, As, Ag, Hg) or agricultural sources (e.g. Cu) in the main fluvial tributaries (Garonne and Dordogne Rivers). However, little peer-reviewed scientific work has addressed the impact of urban sources on the Gironde Estuary, especially the Urban Agglomeration of Bordeaux (~1 million inhabitants) located on the downstream branch of the Garonne River. In this study, a snapshot sampling campaign was performed in 2011 for characterizing the spatial distribution of dissolved and particulate metal/metalloid (As, Ag, Cd, Pb, Zn, Cu) concentrations in three suburban watersheds: the Jalle of Blanquefort (330 km2), Eau Bourde (140 km2), and Peugue (112 km2). Furthermore, particulate metal Enrichment Factors (EF) were calculated using local geochemical background measured at the bottom of a sediment core (492 cm). Results indicated that metal concentrations displayed a high spatial variability depending on the suburban watershed and the studied element. Local concentrations anomalies were observed for: (i) As in the Eau Bourde River in dissolved (4.2 μg/l) and particulate phases (246 mg/kg; EF= 20) and attributed to a nearby industrial incinerator; (ii) Zn in the Peugue River with maximum dissolved and particulate concentrations of 87 μg/l and 1580 mg/kg (EF=17), respectively, probably due to urban habitation runoff; (iii) Ag in the Jalle of Blanquefort River with high dissolved (74 ng/l) and particulate concentrations (33.7 mg/kg; EF=117) due to industrial activities in the downstream part. Based on hydro

  13. “Gloire immortelle de nos Aïeux” les armes des ancetres dans les agglomerations du sudouest europeen a la fin de l'age du Fer: les exemples de Raso de Candeleda et le Cayla de Mailhac

    Directory of Open Access Journals (Sweden)

    Bertaud, Alexandre

    2015-12-01

    Full Text Available To understand the social interaction in warfare context, and specially claim of warrior ancestors, in this paper, we are going to study remains of anachronistic weapons in two late prehistorical agglomerations in South-Western Europe: Candeleda (Spain, Ávila and Mailhac (France, Aude. Study of discovery contexts is the main point to understand the place took by weaponry in these societies. So we are going to approach the claim of warlordism by the highlighting of ancestors warlords through their weapons.Para entender las relaciones sociales en la esfera guerrera, y particularmente la reclamación de una ascendencia de señor de guerra, en este articulo, vamos a analizar restos de armas anacrónicas en dos aglomeraciones de la final de la Edad del Hierro en Europa suroeste : Candeleda (Ávila, España y Mailhac (Aude, Francia. El estudio de los contextos de descubrimiento es un factor crucial en la comprensión de la posición de armas en estas sociedades. Así, vamos a considerar la reclamación de una élite guerrera por el desarrollo de ascendientes señores de la guerra, a través de sus armas. [fr] Afin d’appréhender les rapports sociaux inhérents à la sphère guerrière, et particulièrement la revendication d’une ascendance de chef de guerre, nous allons, dans cet article, analyser les restes d’armes anachroniques dans deux agglomérations de la fin de l’âge du Fer dans le sud-ouest européen : Candeleda et Mailhac. L’étude des contextes de découvertes est alors primordiale dans la compréhension de la place de l’armement dans ces sociétés. Nous allons ainsi pouvoir approcher la revendication d’une élite guerrière par la mise en valeur des ancêtres chefs de guerre à travers leurs armes.

  14. 长株潭城市群土壤pH与重金属污染的研究%The Correlation of Heavy Metal with pH in Soils from Changsha-Zhuzhou-Xiangtan Urban Agglomeration

    Institute of Scientific and Technical Information of China (English)

    岳建华

    2012-01-01

    为了研究土壤样品pH和土壤中重金属含量的相关关系,对长株潭城市群60个土壤样品中pH、有机质含量和重金属含量进行分析.结果表明:长株潭城市群的60个采样点中,13.3%的土壤样品pH<5.0,35%的土壤样品的pH在5.0~6.5之间,41.7%的土壤样品pH在6.5~7.5之间,10%的土壤样品pH在7.5~8.5之间,无强碱性样品.长株潭地区不同土壤pH范围的重金属平均含量不同,随着土壤pH由强酸性、酸性到中性的升高,重金属含量显著提高,但当pH超过7.5,碱性土壤中的重金属含量呈下降趋势.%In order to investigate the correlations of heavy metal with pH in soils, the pH, organic matter contents and heavy metal concentration of 60 soil samples collected from Changsha-Zhuzhou-Xiangtan urban agglomeration were analyzed. The results showed that, the pH of 13.3% samples were lower than 5.0, 35% of samples were 5.0-6.5, 41.7% of samples were 6.5-7.5 and 10% of samples were 7.5-8.5. In conclusion, different mean heavy metal concentrations in soil samples were achieved during various pH ranges. The heavy metals contents increased significantly with the pH of soils increased from strong acidic, acidic soils to neutral soils. However, the heavy metal contents decreased in alkaline soil samples when the pH over 7.5.

  15. Study on Vegetation Carbon Storage and Carbon Density of Changsha-Zhuzhou-Xiangtan Urban Agglomeration%长株潭城市群植被碳贮量与碳密度研究

    Institute of Scientific and Technical Information of China (English)

    陈振雄; 何华

    2016-01-01

    利用湖南2014年森林资源清查样地资料,采用系统抽样理论,综合运用回归模型方法对长株潭地区绿地植被(乔、灌、草)碳贮量与碳密度进行了研究,为建立碳汇计量监测体系提供可靠数据,以期为科学评价区域植被在碳平衡中的作用提供依据。研究结果表明:长株潭地区植被总碳贮量为47.31 Tg (1Tg=1012g),森林植被碳贮量为39.22 Tg,占植被总量的89.73%,其中乔木层碳贮量占71.7%、灌木层碳贮量占22.8%、草本层碳贮量占5.5%;植被平均碳密度为16.9 t/hm2,森林植被平均碳密度为29.53 t/hm2;自然地理因子与植被碳密度具有明显相关性。%In order to provide reliable data for the measurement and monitoring system of carbon sink ,and e-valuate the role of vegetation in the carbon balance . In this paper,based on original data of Hunan forest continuous inventory in 2014,the vegetation carbon storage and carbon density of Changsha-Zhuzhou-Xiang-tan urban agglomeration were studied.The results showed that:the total vegetation carbon storage was 47. 31 Tg,forest vegetation carbon storage was 39. 22 Tg,account for 89. 73%;In forest vegetation storage,the carbon storage of tree layer,shrub layer,herb layer account were 71. 7% and 22. 8% and 5. 5% respective-ly;the average vegetation carbon density was 16. 9 t/hm2 ,the average carbon density of forest vegetation was 29. 53 t/hm2 .Natural geographical factors and vegetation carbon density had a significant correlation.

  16. The Response Mechanism of Village-Level Economy on Industrial Agglomeration Area in Less Developed Rural Area: A Case Study of Wangpangzhuang Village, Kaifeng County, Henan Province%欠发达农区村域经济对产业集聚区的响应机制研究--以河南省王胖庄为例

    Institute of Scientific and Technical Information of China (English)

    许家伟; 李培蕾; 乔家君; 何长涛

    2012-01-01

    以河南省开封县黄龙产业集聚区相邻的王胖庄为研究区域,利用实地调研数据,采用统计方法和SPSS17.0软件计量分析,探讨了村域经济对产业集聚区的响应机制。①产业升级。农户从事第二、三产业的人数增多.同时,粮食作物逐渐转向经济作物。②职业转化。通过务工、自主创业以及外出务工回流的方式实现了村域人口在就业空间上的转移。③思想冲击。耕地的重要程度降低,从事非农产业的积极性提升,生活方式高级化,向往城市生活的愿望强烈。④分化加剧。面对外界刺激,农户逐渐分化为发展型,稳定型和衰退型。⑤农户对产业集聚区的响应程度与核心劳动力年龄、人均耕地面积呈负相关,与劳动力教育年限、劳动力数量呈正相关。%The paper takes wangpangzhuang village as the study area which is proximate to Huanglong industrial agglomeration area in Kaifeng county, Henan province, and uses field survey data by adopting statistical methods and econometric software SPSS17.0 to explore the response mechanism of-village-level economy on industrial agglomeration area.(1) The industrial structure upgraded. The proportion of primary industry declines, the second and tertiary industry rises. Within the primary industry, the weight of industrial crops increases, and the proportion of food crops falls. (2)The occupation shift quickened. The villagers transfer from agriculture to non-agricultural industrial through hiring out for work in industrial agglomeration area and undertaking independent. At the same time, the villagers achieve the transfer of employment space; there is a trend to flow industrial agglomeration area. (3) Ideas impacted. Industrial agglomeration area is heterogeneity to stimulate thinking of households, thus it could produce a larger transformation: weakening importance of land, enhancing enthusiasm of non

  17. The Heterogeneity of Manufacturing Agglomeration and Its Influencing Factors---A Study Based on Employment Lorenz Curves and Their Decompositions%制造业集聚的异质性及影响因素--基于就业洛伦兹曲线及其分解的分析

    Institute of Scientific and Technical Information of China (English)

    覃成林; 种照辉; 任建辉

    2016-01-01

    With the advent of the era of industry 4. 0,China had launched the plan of“China manufac-turing 2025”,in order to achieve the goal of becoming a powerful manufacturing country. Studying the influ-ence factors of manufacturing agglomeration has important implications for the local government to develop the direction of manufacturing industry based on the local manufacturing base and traffic conditions,and have been important issues during the 13th Five - Year Plan period. Based on the employment Lorenz curves and their decompositions by subsector and improve accessibility index,the paper studies the spatial clustering character-istics of four kinds of technology intensive manufacturing industry and the influence factors. The results show that the degree of agglomeration of manufacturing industry is positively related to the degree of technology. De-composing the Lorenz curve by technology intensive degree and traffic conditions,we find that the better the regional manufacturing base is,the more conducive to attracting high,medium and high industries agglomer-ate. The impact of regional traffic conditions is that,the high technology - intensive manufacturing and middle high technology - intensive manufacturing agglomerate on space with good traffic conditions,low technology -intensive manufacturing industries tend to agglomerate on space with middle traffic conditions,while the impact of traffic conditions on middle low technology - intensive manufacturing industry agglomeration shows no obvi-ous regularity. The above conclusions have the reference value for the central government to guide the transfer of industries and the local government to make choice of industry selection.%随着工业4.0时代的到来,我国推出了“中国制造2025”规划。分析各类制造业集聚的影响因素,是研究新集聚格局形成与区域制造业转型升级需要重视的理论问题,也对地方政府根据本地制造业基础及交通条件选择制造业

  18. A Study of the “Yangtze River Middle Reach Delta” Urban Agglomeration:from the Perspective of the Gravity Model%“中三角”城市群研究:基于引力模型的视角

    Institute of Scientific and Technical Information of China (English)

    习明明; 张进铭

    2012-01-01

    The analysis based on the gravity model shows that the intensity of economic relation in Wuhan,Changsha and Nanchang is obviously higher than other combinations of provincial capitals of the six provinces in Central China.Therefore,we should build the "Yangtze River Middle Reach Delta" economic zone covering the core cities of Wuhan,Changsha and Nanchang,the city groups of the Great Wuhan Urban Agglomeration,the Changsha-Zhuzhou-Xiangtan urban agglomeration,and the Poyang Lake Ecological urban agglomeration,as well as Jingzhou City of Hubei and Pingxiang City of Jiangxi,and mold the fourth pole of Chinese economic growth after the Pearl River Delta,the Yangtze River Delta and the Bohai Sea Economic Circle,so as to provide new support and driving force for realizing the rise of Central China and the sustainable economic development of our country.%引力模型的分析表明,武汉、长沙、南昌之间的经济联系强度明显高于中部六省的其他省会城市组合。由此,构建以武汉—长沙—南昌为中心城市,涵盖大武汉城市群、长株潭城市群、鄱阳湖生态城市群,以及湖北荆州、江西萍乡在内的"中三角"经济区,打造继珠三角、长三角、环渤海之后中国经济增长的第四极,为实现中部崛起、实现我国经济可持续发展提供新的支撑和动力。

  19. Industrial Agglomeration of Agro-food Processing Industry:Empirical Analysis Based on Data about 17 Segment Industries%我国农副食品加工业的产业集聚——基于17个四位数行业数据的实证分析

    Institute of Scientific and Technical Information of China (English)

    李鹏; 曾光

    2012-01-01

    This paper uses the spatial concentration index,namely EG coefficient,and the concentration ratio index,to estimate the agglomeration degree of 17 segment industries along to agro-food processing industry during 2003-2009.Then it studies the agglomeration of agro-food processing industry from the aspects of the trend of industrial agglomeration,spatial distribution,the feature of industrial agro-food processing industry and the spatial distribution of raw materials.The results show as follows:during 2003-2009,the concentration degree of agro-food processing industry takes on a declining trend,which is mainly affected by raw material;there exists larger difference in concentration degree of different industries,which is caused by natural environment and geographical location.%采用衡量空间集聚程度的EG指数,并结合产业集中度指数,测算了2003—2009年我国农副食品加工业的17个细分行业的集聚程度,并从产业集聚程度的变动趋势、产业集聚特征、原料主产区的空间分布等方面进行分析。结果表明:在考察期间,我国农副食品加工业的行业集聚程度呈下降态势,行业集中程度主要受原料产地的影响;不同细分行业的集中程度存在较大差异,这是由自然环境和地理位置不同造成的。

  20. 2008年中国种植业地理集聚与专业化格局%Geographical Agglomeration and Specialized Pattern of Planting in China Based on the Different Classifications

    Institute of Scientific and Technical Information of China (English)

    李二玲; 朱纪广; 李小建

    2012-01-01

    There has been less current literature on the pattern of Chinese agricultural geographic concentration and specialization. This paper discusses the geographic concentration pattern of China's planting in 2008. Through calculating the average Gini coefficient (0.46,0.66 and 0.68, respectively), the average Moran' s I index (0.11,0.18 and 0.20, respectively ) and the Location quotient (LQ) in the three scale classifications at the provin- cial level, it is found that the planting in China presents certain geographic concentration and exposes different agglomeration degree at different levels of industrial classification. And the finer division of planting industry, the more obvious the trend of spatial concentration and specialization of production. At the macro-planting level, the distribution of crop production is relatively dispersed, while at the micro-planting level, the distribution of crop production shows the trend of more agglomeration and specialization. The regional specialized production pattern in Chinese planting has emerged. The regional specialized degree of the staple crops is low, and that of the commercial crops is relatively high. Although the specific pattern of spatial concentration is determined by the matching between the natural conditions and production conditions of various crops, the government deci- sion-making, institutional changes and other social factors plays an important role in regional specialized produc- tion functioning as the optimization and adjustment to the natural gathering. So, by calculating the spatial auto- correlation and the Gini coefficient, specialized index in various types of crops grown in contiguous spatial pat- terns, the potential location of the agricultural regional specialization and large-scale production can be identi- fied, which can help the government make specific agricultural policies in different regions.%目前对农业地理集聚和专业化发展的研究较少。本

  1. Spatial Organization of Production Networks in City-Region Based on Enterprises Relationship: A Case of Apparel Production in Urban Agglomeration of Eastern Guangdong Province%基于企业微观视角的城市区域生产网络空间组织研究——以粤东城镇群服装生产为例

    Institute of Scientific and Technical Information of China (English)

    马海涛; 方创琳

    2011-01-01

    城镇间的产业联系是城市(镇)群研究的重要内容之一,然而传统研究多使用宏观统计数据,缺少从企业微观层面对城市产业联系的研究,难以清晰刻画城镇之间复杂的产业联系。随着社会网络分析方法在多学科的运用,城镇群生产网络空间组织的可视化表达和定量分析成为可能。选择粤东城镇群的服装生产为案例,通过深度访谈构建企业关系数据库,运用社会网络分析软件直观模拟城镇群区域服装生产网络,探讨城镇空间结构与生产网络之间的内在联系。结果发现:①粤东城镇群区域内形成了复杂的生产网络,从网络结构上看,大部分节点存在于一个大的网络中,建立直接或间接联系,仅有个别点或小集团孤立在外,网络中各企业的度数中心度和中间中心度存在较大差别;②从网络空间上看,汕头同潮州和普宁都存在密切联系,但潮州和普宁之间缺少联系,而汕尾孤立于汕潮揭之外;③各等级城镇在粤东城镇群区域服装生产网络中发挥了不同的作用,城镇的专业化与区域的多样化共同推动服装生产的网络化。为城镇群内部经济联系研究提供了新的思路与方法,对城镇群网络化建设具有参考价值。%Spatial relationship of geographical actors is one of the core topics of geography. In urban geography, the internal industrial relationship between cities or towns, the same as spatial relationship, is also a significant part of the urban agglomeration study. A great many geographers engage themselves in studying the internal socio-economic relationship between cities by using macro-statistics. However, enterprise is the principle part of the relationship, lacking micro-perspective when studying is hard to explain