WorldWideScience

Sample records for agglomeration

  1. Defining urban agglomerations to detect agglomeration economies

    CERN Document Server

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

    2016-01-01

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

  2. Agglomeration and Market Interaction

    OpenAIRE

    Fujita, Masahisa; Thisse, Jacques-François

    2002-01-01

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

  3. Agglomeration and Co-Agglomeration of Services Industries

    OpenAIRE

    Kolko, Jed

    2007-01-01

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

  4. Nucleation of point defect agglomerates

    International Nuclear Information System (INIS)

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

  5. Agglomeration processes in aging societies

    OpenAIRE

    Theresa Grafeneder-Weissteiner; Klaus Prettner

    2010-01-01

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

  6. Microbial effects on colloidal agglomeration

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    ZOBOVA L.L.; SHABASHEV V.A.

    2016-01-01

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

  8. 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...... using historical data on composers and employ a unique instrumental variable – a measure of birth centrality, calculated as the average distance between a composer’s birthplace and the birthplace of his peers. I find a strong causal impact of peer group size on the number of important compositions...

  9. Agglomeration, Integration and Tax Harmonization

    OpenAIRE

    Richard Baldwin; Paul Krugman

    2001-01-01

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

  10. Agglomeration and the product mix

    OpenAIRE

    Dalvai, Wilfried

    2016-01-01

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

  11. Powder agglomeration in a microgravity environment

    Science.gov (United States)

    Cawley, James D.

    1994-01-01

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

  12. Agglomeration patterns in the Polish manufacturing industry

    Directory of Open Access Journals (Sweden)

    Tomasz Brodzicki

    2012-01-01

    Full Text Available External liberalization should affect regional agglomeration patterns in manufacturing industry. In Poland, the largest CEE economy, economic transition was marked by accelerated restructuring associated with relatively rapid external trade and capital flows liberalization. The process of economic transition was reinforced by accession to the EU. Economic transition could potentially have a sizeable impact on industrial agglomeration patterns. Using sectoral agglomeration indices we examine changes in the agglomeration patterns of the Polish manufacturing industry. The analysis is carried out on a disaggregated data set on employment for 2 and 3-digit NACE manufacturing industry sectors at the level of local administrative districts (LAD4 level. The data set covers the period 1999-2006. The overall agglomeration index for Polish manufacturing industry decreased only by 0.5 percent within the analyzed period of time. The patter of agglomeration remained largely unaffected despite of significant structural adjustments in other areas.

  13. Industrial Scope of Agglomeration Economies in Brazil

    OpenAIRE

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

    2015-01-01

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

  14. Human Capital, Talent, Agglomeration and Regional Growth

    OpenAIRE

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

    2009-01-01

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

  15. 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.

  16. SPHERICAL AGGLOMERATION – DIRECT TABLETTING TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Patil Pradnya B.

    2011-11-01

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

  17. 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.

  18. Spectral-element agglomerate coarsening in AMGe

    Energy Technology Data Exchange (ETDEWEB)

    Vassilevski, P S

    2000-12-06

    In this talk the authors present a highly accurate coarsening algorithm for constructing coarse finite element spaces to be used in algebraic multigrid methods designed for finite element problems on generally unstructured meshes. The new algorithm relies on removing certain percentage of the high oscillating components from the spectrum of local stiffness matrices corresponding to element agglomerations. By doing so, one is guaranteed that the hierarchical complement finite element subspace gives rise to a well conditioned matrix. The coarsening consists of an agglomeration step and of computing a few minimal eigenvectors of the corresponding assembled agglomerate stiffness matrix. The method requires access to the individual element matrices. Based on the topological agglomeration algorithms they employed one is able to define coarse elements and coarse element matrices thus allowing for recursive use of the same algorithm. Some numerical illustration for elliptic problems is also given.

  19. Agglomeration of Charged Nanopowders in Suspensions

    OpenAIRE

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

    2002-01-01

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

  20. 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

  1. Mechanics and charging of nanoparticle agglomerates

    Science.gov (United States)

    Shin, Weon Gyu

    This thesis consists of two parts. The first part concerns studies on mechanics of real agglomerate particles and the second part involves studies on unipolar diffusion charging of agglomerates. Understanding mechanics of real agglomerate particles consisting of multiple primary particles is important for aerosol sizing instrumentation using electrical mobility and nanoparticle manufacturing process where coagulation and sedimentation occur. A key quantity determining transport properties of agglomerates is the friction coefficient. However, quantitative studies for the friction coefficient of agglomerates are very limited. Transmission Electron Microscopy (TEM) image analysis results of silver agglomerates provides a basis for the comparison of experimental data with estimates based on free molecular models. A new quantitative method to determine the dynamic shape factor and the two exponents, eta and Dfm, which characterize the power law dependence of friction coefficient on the number of primary spheres and the mass on the mobility diameter, was developed using Differential Mobility Analyzer (DMA)-Aerosol Particle Mass (APM) analyzer. Model predictions indicate that eta is independent of agglomerate size while Dfm is sensitive to agglomerate size. Experimentally, it appears the opposite is true. Tandem DMA (TDMA) results also show that the mass-mobility diameter scaling exponent is not dependent on mobility size range. Estimates of non-ideal effects on the agglomerate dynamics were computed as perturbations to the Chan-Dahneke agglomerate model. After the corrections, an agreement between experimental data and model predictions becomes significantly improved. Unipolar diffusion charging becomes more attractive because it has higher charging efficiency than bipolar charging as well as important applications in aerosol sizing instrumentation using electrical mobility, powder coating, and the removal of toxic particles from air stream using Electrostatic

  2. 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...

  3. Measuring Agglomeration Forces in a Financial Center

    OpenAIRE

    Bourgain, Arnaud; Pieretti, Patrice

    2006-01-01

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

  4. Industrial Agglomeration and Use of the Internet

    NARCIS (Netherlands)

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

    2015-01-01

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

  5. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-15

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

  7. Fibre agglomerate transport in a horizontal flow

    International Nuclear Information System (INIS)

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

  8. 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

  9. Industry-specific firm growth and agglomeration

    OpenAIRE

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

    2013-01-01

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

  10. 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.

  11. Encapsulation of hazardous wastes into agglomerates

    International Nuclear Information System (INIS)

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

  12. 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.

  13. 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.

  14. The soundscape dynamics of human agglomeration

    CERN Document Server

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

    2011-01-01

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

  15. Important characteristics of a gas-promoted oil agglomeration process

    Energy Technology Data Exchange (ETDEWEB)

    Shen, M.; Wheelock, T.D. [Iowa State University, Ames, IA (United States)

    1998-12-31

    The characteristics of a gas-promoted oil agglomeration process for cleaning coal particles in an aqueous suspension were determined by conducting a large number of agglomeration tests with scale model mixing systems of different sizes with controlled amounts of air present. The tests were conducted with both high-volatile and medium-volatile bituminous coals using iso-octane as an agglomerant. The results indicated that the process can be characterized by the minimum time required to produce spherical agglomerates t{sub E} the mean diameter d{sub p} of the agglomerates produced in a specific time, coal recovery, and product ash content. Among these parameters t{sub E} appears to hold the key for size scale-up of an agglomeration mixing system, and an appropriate scale-up rule is proposed. 8 refs., 3 figs., 1 tab.

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

    Science.gov (United States)

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

    2013-03-01

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

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

    NARCIS (Netherlands)

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

    2012-01-01

    Problems related to the blending of a cohesive powder with a free flowing bulk powder are frequently encountered in the pharmaceutical industry. The cohesive powder often forms lumps or agglomerates which are not dispersed during the mixing process and are therefore detrimental to blend uniformity.

  18. The Structure of Agglomerates consisting of Polydisperse Particles

    OpenAIRE

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

    2012-01-01

    Agglomeration is encountered in many natural or industrial processes, like growth of aerosol particles in the atmosphere and during material synthesis or even flocculation of suspensions, granulation, crystallization and with colloidal particle processing. These particles collide by different mechanisms and stick together forming irregular or fractal-like agglomerates. Typically, the structure of these agglomerates is characterized with the fractal dimension, Df, and pre-exponential factor, k...

  19. Coagulation of Agglomerates Consisting of Polydisperse Primary Particles.

    Science.gov (United States)

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

    2016-09-13

    The ballistic agglomeration of polydisperse particles is investigated by an event-driven (ED) method and compared to the coagulation of spherical particles and agglomerates consisting of monodisperse primary particles (PPs). It is shown for the first time to our knowledge that increasing the width or polydispersity of the PP size distribution initially accelerates the coagulation rate of their agglomerates but delays the attainment of their asymptotic fractal-like structure and self-preserving size distribution (SPSD) without altering them, provided that sufficiently large numbers of PPs are employed. For example, the standard asymptotic mass fractal dimension, Df, of 1.91 is attained when clusters are formed containing, on average, about 15 monodisperse PPs, consistent with fractal theory and the literature. In contrast, when polydisperse PPs with a geometric standard deviation of 3 are employed, about 500 PPs are needed to attain that Df. Even though the same asymptotic Df and mass-mobility exponent, Dfm, are attained regardless of PP polydispersity, the asymptotic prefactors or lacunarities of Df and Dfm increase with PP polydispersity. For monodisperse PPs, the average agglomerate radius of gyration, rg, becomes larger than the mobility radius, rm, when agglomerates consist of more than 15 PPs. Increasing PP polydispersity increases that number of PPs similarly to the above for the attainment of the asymptotic Df or Dfm. The agglomeration kinetics are quantified by the overall collision frequency function. When the SPSD is attained, the collision frequency is independent of PP polydispersity. Accounting for the SPSD polydispersity in the overall agglomerate collision frequency is in good agreement with that frequency from detailed ED simulations once the SPSD is reached. Most importantly, the coagulation of agglomerates is described well by a monodisperse model for agglomerate and PP sizes, whereas the detailed agglomerate size distribution can be obtained by

  20. Agglomeration of coal fines for premium fuel application

    International Nuclear Information System (INIS)

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

  1. Fluid bed agglomeration with a narrow droplet size distribution

    NARCIS (Netherlands)

    Schaafsma, SH; Vonk, P; Kossen, NWF

    2000-01-01

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

  2. 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...

  3. 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

  4. Urban Agglomerations in Regional Development: Theoretical, Methodological and Applied Aspects

    Directory of Open Access Journals (Sweden)

    Andrey Vladimirovich Shmidt

    2016-09-01

    Full Text Available The article focuses on the analysis of the major process of modern socio-economic development, such as the functioning of urban agglomerations. A short background of the economic literature on this phenomenon is given. There are the traditional (the concentration of urban types of activities, the grouping of urban settlements by the intensive production and labour communications and modern (cluster theories, theories of network society conceptions. Two methodological principles of studying the agglomeration are emphasized: the principle of the unity of the spatial concentration of economic activity and the principle of compact living of the population. The positive and negative effects of agglomeration in the economic and social spheres are studied. Therefore, it is concluded that the agglomeration is helpful in the case when it brings the agglomerative economy (the positive benefits from it exceed the additional costs. A methodology for examination the urban agglomeration and its role in the regional development is offered. The approbation of this methodology on the example of Chelyabinsk and Chelyabinsk region has allowed to carry out the comparative analysis of the regional centre and the whole region by the main socio-economic indexes under static and dynamic conditions, to draw the conclusions on a position of the city and the region based on such socio-economic indexes as an average monthly nominal accrued wage, the cost of fixed assets, the investments into fixed capital, new housing supply, a retail turnover, the volume of self-produced shipped goods, the works and services performed in the region. In the study, the analysis of a launching site of the Chelyabinsk agglomeration is carried out. It has revealed the following main characteristics of the core of the agglomeration in Chelyabinsk (structure feature, population, level of centralization of the core as well as the Chelyabinsk agglomeration in general (coefficient of agglomeration

  5. 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

  6. 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

  7. Novel Binders and Methods for Agglomeration of Ore

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-03-31

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

  8. Novel Binders and Methods for Agglomeration of Ore

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-09-30

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

  9. Fragmentation and bond strength of airborne diesel soot agglomerates

    Directory of Open Access Journals (Sweden)

    Messerer Armin

    2008-06-01

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

  10. 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.

  11. 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.

  12. 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.

  13. 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)

  14. Characterization of the geometrical properties of agglomerated aerosol particles

    International Nuclear Information System (INIS)

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

  15. 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.

  16. 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...

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

    OpenAIRE

    De Beule, Filip; Van Beveren, Ilke

    2010-01-01

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

  18. Defect agglomeration in ferroelectric ceramics under cyclic electric field

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

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

  19. Marshallian Agglomeration Economies and Entrepreneurship: The Spanish Case

    OpenAIRE

    Fernandez, Roberto Dopeso

    2011-01-01

    This paper analyzes to what extent marshallian agglomeration economies affect the creation of new entrepreneurial ventures at the metropolitan level. The measuring of agglomeration economies is based on the construction of indexes using the methodology of Glaeser and Kerr (2009). The indexes attempt to capture the effects of resource sharing, labor matching and knowledge spillovers according to the taxonomy proposed by Marshall (1920). Also an index to measure the influence of small suppliers...

  20. 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.

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

    OpenAIRE

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

    2015-01-01

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

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. Theranostic potential of gold nanoparticle-protein agglomerates

    Science.gov (United States)

    Sanpui, Pallab; Paul, Anumita; Chattopadhyay, Arun

    2015-11-01

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

  7. 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.

  8. 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.

  9. 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.

  10. Engineering development of selective agglomeration. Site closeout report

    Energy Technology Data Exchange (ETDEWEB)

    1993-04-01

    The Selective Agglomeration POC facility consisted of a coal crushing and grinding circuit, followed by an agglomeration circuit and product dewatering. (A plot plan of the facility is shown in Figure 1-2.) The coal crushing and grinding system consisted of a hammermill coal crusher, weigh-belt feeder, two ball mills (primary and secondary), and necessary hoppers, pumps, and conveyors. The mills were capable of providing coal over a range of grinds from a d{sub 50} of 125 to 25 microns. Slurry discharged from the ball mills was pumped to the agglomeration circuit. The agglomeration circuit began with a high-shear mixer, where diesel was added to the slurry to begin the formation of microagglomerates. The high-shear mixer was followed by two stages of conventional flotation cells for microagglomerate recovery. The second-stage-flotation-cell product was pumped to either a rotary-drum vacuum filter or a high-G centrifuge for dewatering. The dewatered product was then convoyed to the product pad from which dump trucks were used to transfer it to the utility plant located next to the facility. Plant tailings were pumped to the water clarifier for thickening and then dewatered in plate-and-frame filter presses. These dewatered tailings were also removed to the utility via dump truck. Clarified water (thickener overflow) was recycled to the process via a head tank.

  11. 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.

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

    OpenAIRE

    Gladkyj O.V.

    2009-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Gladkyj O.V.

    2009-08-01

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

  14. 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.

  15. 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.

  16. MANIPULATION OF PHYSICAL FUNCTIONALITY OF BULK DRUG POWDER: AGGLOMERATE SIZE APPROACH

    Directory of Open Access Journals (Sweden)

    Kale Vinita

    2011-06-01

    Full Text Available Agglomeration is a size enlargement process in which primary particles stick together to form agglomerates. In past, various techniques have been developed to form agglomerates. One of the aims of this study was to form agglomerates using solvent treated method and traditional wet granulation method of a bulk drug and to study the effect of agglomeration on physical functionality of agglomerated and original bulk powders. Another objective of the study was to prepare compact of the agglomerated powders and bulk powder and to study their compactibility properties. The solvent treated agglomeration process was performed using 5% aqueous ammonia solution at different stirring speed and time. Powder flow and compactibility were considered as functionality parameters. Powder flowability was expressed in terms of – size and shape of particles, static angle of repose, Hausner ratio, Carrs index, porosity and packability. The compacts of agglomerated powders and bulk powder were prepared and tested for compressibility properties. All the powder functional properties of the solvent treated agglomerates were dramatically improved. Compacts by direct compression method could be formed successfully of solvent treated agglomerate powder that was comparable with the wet granules. The original powder of bulk drug failed to be compressed by direct compression method. Thus solvent treated agglomerates provided the requirements needed to convert wet granulated formulations to direct compression formulations, thus avoiding labor and energy intensive of wet granulation processes and is an alternative to develop cost effective formulations.

  17. 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

  18. 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.

  19. 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...

  20. Experimental study of fluidized bed agglomeration of acerola powder

    Directory of Open Access Journals (Sweden)

    G. C. Dacanal

    2008-03-01

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

  1. 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

  2. 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.

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

    Directory of Open Access Journals (Sweden)

    Zheng Jian-Xiang

    2014-01-01

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

  4. 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....... The first is that policy strategies should not try to be hegemonic. Instead, they should be elaborated seeking complementarity and coexistence. A second normative conclusion is the necessity of fostering the learning processes within and across institutions, by mobilizing collectively the assets of the area...... 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....

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

    OpenAIRE

    Canfei He; Qi Guo; David Rigby

    2015-01-01

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

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

    OpenAIRE

    Toulemonde, Eric

    2003-01-01

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

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

    OpenAIRE

    Hugh B. Wenban-Smith

    2009-01-01

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

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

    OpenAIRE

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

    2014-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-10-14

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

  10. 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.

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

    International Nuclear Information System (INIS)

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

  12. 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.

  13. Agglomeration and Deposition Behaviour of Solid Recovered Fuel

    DEFF Research Database (Denmark)

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

    2016-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    BINGQIAO YANG; SHAOXIAN SONG

    2014-01-01

    Hydrophobic agglomeration is originated from the hydrophobic attraction between particles, which is essentially different from electrolyte coagulation and polymer flocculation. It is applied to mineral processing in floc-flotation process to improve the recovery of mineral fines. In this paper, the applications of this phenomenon in mineral fines were summarized, including the origin of hydrophobic agglomeration, the main factors affect hydrophobic agglomeration (particle hydrophobicity, shea...

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

    OpenAIRE

    Rosero, Grace Carolina Guevara

    2015-01-01

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

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

    OpenAIRE

    Tripathi, Sabyasachi

    2012-01-01

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

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

    DEFF Research Database (Denmark)

    Kiil, Søren

    2016-01-01

    The purpose of this work is to develop a mathematical model that can quantify the dispersion of pigments, with a focus on the mechanical breakage of pigment agglomerates. The underlying physical mechanism was assumed to be surface erosion of spherical pigment agglomerates. The full agglomerate pa.......g., in the development of novel dispersion principles and for analysis of dispersion failures. The general applicability of the model, beyond the three pigments considered, needs to be confirmed....

  20. 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.

  1. 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.

  2. 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.

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

    Science.gov (United States)

    Knoop, Claas; Fritsching, Udo

    2013-10-01

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

  4. 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.

  5. 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.

  6. 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...... 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...... 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...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-02-15

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

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

    International Nuclear Information System (INIS)

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

  9. 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...

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

    OpenAIRE

    Teller, C; Thomson, A

    2012-01-01

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

  12. 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

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

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    王力; 陈鹏

    1997-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-02-15

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

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

    Science.gov (United States)

    Tijerino, Erick; Basu, Saptarshi; Kumar, Ranganathan

    2013-01-01

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

  18. 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.

  19. 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.

  20. 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.

  1. Nearshore dynamics of artificial sand and oil agglomerates.

    Science.gov (United States)

    Dalyander, P Soupy; Plant, Nathaniel G; Long, Joseph W; McLaughlin, Molly

    2015-07-15

    Weathered oil can mix with sediment to form heavier-than-water sand and oil agglomerates (SOAs) that can cause beach re-oiling for years after a spill. Few studies have focused on the physical dynamics of SOAs. In this study, artificial SOAs (aSOAs) were created and deployed in the nearshore, and shear stress-based mobility formulations were assessed to predict SOA response. Prediction sensitivity to uncertainty in hydrodynamic conditions and shear stress parameterizations were explored. Critical stress estimates accounting for large particle exposure in a mixed bed gave the best predictions of mobility under shoaling and breaking waves. In the surf zone, the 10-cm aSOA was immobile and began to bury in the seafloor while smaller size classes dispersed alongshore. aSOAs up to 5 cm in diameter were frequently mobilized in the swash zone. The uncertainty in predicting aSOA dynamics reflects a broader uncertainty in applying mobility and transport formulations to cm-sized particles.

  2. Natural and agglomerated stone durability assessment according to technical standards

    Directory of Open Access Journals (Sweden)

    Ivana Šimková

    2010-01-01

    Full Text Available The assessment of rock behaviour and durability plays an important role in the use of rocks and similar materials for all building purposes. Durability is a complex term, therefore the paper deals with the terminology and aspects related to the evaluation and prediction possibilities of stone durability. Technical standards offer some laboratory procedures suitable for stone durability assessment. The paper presents the results of the application of some standard laboratory methods on select types of natural and agglomerated stones, from the physical properties determination and durability assessment point of view. On the basis of defined criteria of physical properties, such as the value of open porosity, uniaxial compressive strength and water absorption, was predicted the behaviour of selected stones against ageing and weathering. Results of the realised laboratory weathering tests such as the determination of resistance to frost and salt crystallisation, determination of resistance to ageing by SO2 action in the presence of humidity, and determination of resistance to thermal shock, confirmed and verified rock behaviour conditional on stone genesis, mineral composition and structural characteristics.

  3. Radiation-induced silver agglomeration in molecular sieves: a comparison between A and X zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Sadlo, J.; Wasowicz, T.; Michalik, J. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

    1995-06-01

    The stabilization conditions of silver atoms and clusters in hydrated and dehydrated AgNa-A and AgNa-X zeolites {gamma}-irradiated at 77 K have been studied by ESR. It was found that silver agglomeration mechanisms in hydrated A and X zeolites are very similar and are controlled by the migration of silver atoms into the {alpha}-cages. In dehydrated zeolites agglomeration leads to completely different silver clusters in A and X zeolites. Small cationic clusters are stabilized in A zeolites and metallic clusters in X zeolites. Various factors affecting the agglomeration process in A and X zeolites are discussed. (author).

  4. Magnetic Agglomeration Among Nd-Fe-B Particles and Its Influence on Field Aligning

    Institute of Scientific and Technical Information of China (English)

    何叶青; 王震西; 周寿增; 张臻蓉; 韩宝善

    2004-01-01

    There exists strong magnetic agglomeration among Nd-FeB particles. Due to this effect, an applied field even up to 1350 kAm-1 still can not make the loose Nd-Fe-B powders to reach saturated magnetization. SEM images of a little amount of Nd-Fe-B powders were used to illustrate the agglomeration phenomenon. We believe that the general existence of misalignment grains in the magnetic force images of the sintered Nd-FeB magnet fabricated by die pressing with 1500 kAm-1 aligning field is a confirmation of the magnetic agglomeration.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Zirconia nanoceramic via redispersion of highly agglomerated nanopowder and spark plasma sintering.

    Science.gov (United States)

    Suárez, Gustavo; Borodianska, Hanna; Sakka, Yoshio; Aglietti, Esteban F; Vasylkiv, Oleg

    2010-10-01

    A 2.7 mol% yttria stabilizing tetragonal zirconia (2.7Y-TZP) nanopowder was synthesized and stored for five years. Humidity and unsatisfactory storage conditions gradually caused heavy agglomeration. Within a few months, 2.7Y-TZP nanopowder became useless for any technological application. A bead-milling deagglomeration technique was applied to recover the heavily agglomerated yttria-stabilized zirconia nanopowder. Low-temperature sintering and spark plasma sintering (SPS) were performed, resulting in fully dense nanostructured ceramics. Compacts formed with heavily agglomerated powder present low sinterability and poor mechanical properties. Bead-milling suspension formed compacts exhibit mechanical properties in the range of the values reported for nanostructured zirconia. This observation confirms the effectiveness of bead-milling in the deagglomeration of highly agglomerated nanopowders. The high value of Vickers hardness of 13.6 GPa demonstrates the success of the processing technique for recovering long-time-stored oxide nanopowders. PMID:21137774

  11. 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.)

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

    NARCIS (Netherlands)

    Bosma, Niels; van Oort, Frank

    2012-01-01

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

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

    Science.gov (United States)

    Knoop, Claas; Fritsching, Udo

    2014-03-01

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

  14. 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.

  15. 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.

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

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2010-01-01

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

  18. 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

  19. 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.

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

    OpenAIRE

    Asim Iqba; Muhammad Wasif Siddiqi

    2013-01-01

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

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

    OpenAIRE

    Gonchar, Ksenia; Ratnikova, Tatyana

    2013-01-01

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

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

    OpenAIRE

    Luis Cabral; Zhu Wang; Daniel Yi Xu

    2013-01-01

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

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

    OpenAIRE

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

    2016-01-01

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

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

    OpenAIRE

    Bosma, Niels; van Oort, Frank

    2012-01-01

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

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

    OpenAIRE

    Teller, C; Reutterer, T; Schnedlitz, P

    2008-01-01

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

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

    OpenAIRE

    Macho Oliver; Peciar Peter; Peciar Marián; Svěrák Tomáš

    2015-01-01

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

  7. 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.

  8. 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.

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

    Science.gov (United States)

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

    2012-11-01

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

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

    Science.gov (United States)

    Wong, Tin Wui; Musa, Nafisah

    2012-07-01

    Conventional melt pelletization and granulation processes produce round and dense, and irregularly shaped but porous agglomerates respectively. This study aimed to design centrifugal air-assisted melt agglomeration technology for manufacture of spherical and yet porous "granulets" for ease of downstream manufacturing and enhancing drug release. A bladeless agglomerator, which utilized shear-free air stream to mass the powder mixture of lactose filler, polyethylene glycol binder and poorly water-soluble tolbutamide drug into "granulets", was developed. The inclination angle and number of vane, air-impermeable surface area of air guide, processing temperature, binder content and molecular weight were investigated with reference to "granulet" size, shape, texture and drug release properties. Unlike fluid-bed melt agglomeration with vertical processing air flow, the air stream in the present technology moved centrifugally to roll the processing mass into spherical but porous "granulets" with a drug release propensity higher than physical powder mixture, unprocessed drug and dense pellets prepared using high shear mixer. The fast-release attribute of "granulets" was ascribed to porous matrix formed with a high level of polyethylene glycol as solubilizer. The agglomeration and drug release outcomes of centrifugal air-assisted technology are unmet by the existing high shear and fluid-bed melt agglomeration techniques. PMID:22531845

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  13. 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.

  14. 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.

  15. 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.)

  16. 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

  17. 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

    . The agglomerates are analyzed by scanning electron microscopy–energy-dispersive X-ray spectrometry (SEM–EDS) for morphology and elemental composition. Significant differences are observed on the defluidization temperature (Td) and agglomeration mechanisms in different gas atmospheres. Td in H2 and steam....... 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...... atmospheres are much lower than that in air. It appears that, in a steam atmosphere, the agglomeration of corn straw and rice straw ash is predominantly coating-induced. The agglomeration in both H2 and air atmospheres are melting-induced. In a H2 atmosphere, K2SO4 in the ash samples disappears, caused...

  18. 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.

  19. 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.

  20. 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.

  1. Impact of a non-meltable additive on melt agglomeration with a hydrophobic meltable binder in high-shear mixer.

    Science.gov (United States)

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

    2007-01-01

    The present study aims to investigate the behavior of melt agglomeration with a low-viscosity hydrophobic meltable binder by using a non-meltable additive. The size, crushing strength, and pore size distribution of resultant agglomerates, the rheological, surface tension, and wetting properties of the molten binder, as well as, the flow characteristics of preagglomeration powder blend were determined. The use of additive showed contradictory agglomerate growth-promoting and -retarding effects on the molten binder surface tension and the interparticulate frictional forces. Critical concentration effects of additive corresponded to threshold transition of agglomeration-promoting to -retarding behavior were discussed. PMID:17763142

  2. 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.

  3. 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.

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

    DEFF Research Database (Denmark)

    Mitze, Timo Friedel; Schmidt, Torben Dall

    2015-01-01

    by “new” migration theories related to regional growth models and the new economic geography. The work contributes to the field in the following way: we extend the scarce literature on the different channels through which agglomeration economies act as an attractor for mobile labor. Moreover, we account...... 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...... 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...

  5. 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.

  6. 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.

  7. 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.

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

    Directory of Open Access Journals (Sweden)

    Macho Oliver

    2015-12-01

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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

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

    OpenAIRE

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

    2010-01-01

    Engineered nanoparticles are increasingly incorporated into consumer products and are emerging as potential environmental contaminants. Upon environmental release, nanoparticles could inhibit bacterial processes, as evidenced by laboratory studies. Less is known regarding bacterial alteration of nanoparticles, including whether bacteria affect physical agglomeration states controlling nanoparticle settling and bioavailability. Here, the effects of an environmental strain of Pseudomonas aerugi...

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

    NARCIS (Netherlands)

    Wang, M.; Vliet, van T.; 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

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

    OpenAIRE

    Debnath Mookherjee

    2004-01-01

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

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

    OpenAIRE

    Debnath Mookherjee; Eugene Hoerauf

    2004-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Debnath Mookherjee

    2004-12-01

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

  19. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-15

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

  1. 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

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

    Science.gov (United States)

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

    2012-02-01

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

  3. 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.

  4. 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.

  5. 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.

  6. 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...

  7. 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

  8. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-31

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-01-15

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

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

    Science.gov (United States)

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

    2013-11-12

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

  12. 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.

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

    Science.gov (United States)

    Tantra, Ratna; Tompkins, Jordan; Quincey, Paul

    2010-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    HILL SR

    2010-06-10

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

  15. 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

  16. 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.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-08-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-31

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

  20. 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.

  1. 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

    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...... for the salt coating process than for the polymer coating process, under similar process conditions. Based on the experimental results, an agglomeration regime map is suggested for each of the two types of coating solutions, based on values of the drying force and the coating solution spray rate....

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

    Institute of Scientific and Technical Information of China (English)

    顾朝林

    2011-01-01

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

  3. 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.

  4. 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.

  5. 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

    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......-scale installations is "coating-induced" agglomeration. During reactor operation, a coating is formed on the surface of bed material grains and at certain critical conditions (e.g., coating thickness or temperature) sintering of the coatings initiates the agglomeration. In an experimental approach, this work...... four times the minimum fluidization velocity, and (c) on the viscosity (stickiness) of the outside of the grains (coating)....

  6. Particle agglomeration during energy recovery from plastic wastes by means of fluidized bed reactors

    Energy Technology Data Exchange (ETDEWEB)

    Arena, U.; Mastellone, M.L.

    1999-07-01

    The occurrence and the significance of agglomeration phenomena during thermal treatments in a fluidized bed reactor of a couple of plastic wastes were studied. A small scale bubbling fluidized bed, made of quartz, was charged with pellets obtained from mono-material collections of polyethylene and polyethylene terephtalate. Batchwise and continuous experiments were carried out at different bed temperatures (from 450 to 850 C), under inert and oxidizing conditions and by operating the reactor with silica sand having a size range of 0.3--0.4 mm. Different mechanisms of defluidization were identified and characterized. The time at which the phenomena occurred, for each of bed temperatures used, was also determined. In particular, the continuous experiments showed that defluidization can occur, with different mechanisms, at temperatures lower than 850 C. An increase of bed temperature as well as that of oxygen content strongly reduces the potential concern of particle agglomeration and bed defluidization.

  7. 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.

  8. 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.

  9. 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...

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

    Institute of Scientific and Technical Information of China (English)

    陈晓方; 桂卫华; 王雅琳; 吴敏

    2003-01-01

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

  11. Bed agglomeration in fluidized combustor fueled by wood and rice straw blends

    DEFF Research Database (Denmark)

    Thy, Peter; Jenkins, Brian; Williams, R.B.;

    2010-01-01

    Abstract Petrographic techniques have been used to examine bed materials from fluidized bed combustion experiments that utilized wood and rice straw fuel blends. The experiments were conducted using a laboratory-scale combustor with mullite sand beds, firing temperatures of 840 to 1030 °C, and run...... durations of 5.5 h. A narrow continuous zone borders virtually all bed particles. The highest concentrations of potassium are found in this surface zone that also is enriched in appreciable amounts of other elements. Thin discontinuous films of adhesive cement, formed preferentially on surfaces and contact...... areas between bed particles, ultimately led to bed agglomeration. The interfaces and the presence of gas bubbles in the cement suggest a bonding material with a high surface tension and a liquid state. The cement films originate by filling of irregularities on individual and partially agglomerated bed...

  12. Industrial Regions, Agglomerations and Industrialisation: The Iron and Steel Industry in Central Sweden 1805-1910

    OpenAIRE

    Olsson, Fredrik

    2006-01-01

    This paper focuses on regional and sectoral aspects of the Swedish industrialisation process. The aim is to discern geographical patterns of industrial agglomerations in the iron industry in Central Sweden during the period 1805-1910. Geographical patterns for the benchmark years 1805, 1855 and 1910 are based on employment statistics, which is analysed with the statistical Cluster Analysis. All parishes’ employment structure are compared at each benchmark year. The results are visualized in m...

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

    Science.gov (United States)

    Zhao, Yun; Zeng, Xinwu; Tian, Zhangfu

    2015-10-01

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

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

    OpenAIRE

    MELICIANI Valentina; Savona, Maria

    2011-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    Tripathi, Sabyasachi

    2012-01-01

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

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

    OpenAIRE

    Xuan Zhaohui; Wu Aizhi; Lv Yongbo

    2013-01-01

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

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

    OpenAIRE

    Hecht, Veronika

    2015-01-01

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

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

    OpenAIRE

    Paci, Raffaele; Usai, Stefano

    1999-01-01

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

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

    International Nuclear Information System (INIS)

    The specific objectives of the bituminous coal program were to explore and evaluate the application of advanced agglomeration technology for: (1)desulphurization of bituminous coals to sulphur content acceptable within the current EPA SO2 emission guidelines; (2) deashing of bituminous coals to ash content of less than 10 percent; and (3)increasing the calorific value of bituminous coals to above 13,000 Btu/lb. (VC)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-02-01

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

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

    OpenAIRE

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

    2015-01-01

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

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

    OpenAIRE

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

    2009-01-01

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

  4. 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.

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

    Science.gov (United States)

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

    2016-01-01

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

  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. 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.

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

    OpenAIRE

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

    2013-01-01

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

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

    OpenAIRE

    Qunfang Huang; Yuqi Lu

    2015-01-01

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

  10. 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

  11. 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”.

  12. 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.

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

    Science.gov (United States)

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

    2013-10-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  15. 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.

  16. Cold Agglomeration of Ultrafine Oxidized Dust (UOD from Ferromanganese and Silicomanganese Industrial Process

    Directory of Open Access Journals (Sweden)

    María Ordiales

    2016-08-01

    Full Text Available Different wastes are generated in ferromanganese and silicomanganese alloy production. One of them is the ultrafine oxidized dust (UOD produced in the collection and control of flying dusts in the ferroalloy industry. This waste has fairly high manganese content (20%–40% Mn, making it suitable to be a secondary raw material for the ferromanganese industry. This research proposes a method for the transformation of UOD into a useable raw material. Cold agglomeration is the best option, due to its low energy consumption. Portland cement and refractory cement are compared as suitable candidates in the management of the UOD for their reuse in the electric arc furnace feed.

  17. 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.

  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. 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%.

  20. Study on Industrial Integration Development of the Energy Chemical Industry in Urumqi-Changji-Shihezi Urban Agglomeration, Xinjiang, NW China

    Directory of Open Access Journals (Sweden)

    Guiling Wang

    2016-07-01

    Full Text Available With industrial integration accelerating in domestic and foreign enterprise, industrial integration is becoming the only way for regional development to break through its bottleneck. Compared with advanced foreign enterprises, there exists a significant gap in regional industrial integration, especially in the urban agglomeration of the energy chemical industries of Urumqi-Changji-Shihezi in Xinjiang. Findings from field visits and quantitative analysis show that the energy chemical industry in urban agglomeration is in a state of dispersed distribution, serious convergence in industrial structure, low level of specialization, and weak collaborative relationships. These issues seriously hamper the sustainable development of urban agglomeration. Specific actions aimed at these problems and the development bottleneck mainly include the integration of industrial parks in the central city and integration orientation on the level of urban agglomeration. Only by speeding up the pace of industry integration can Urumqi-Changji-Shihezi’s urban agglomeration maintain and improve its market competitiveness. Accordingly, it can promote innovation and sustainability in the energy chemical industry and improve the overall level of development.

  1. 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.

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

    Science.gov (United States)

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

    2015-11-10

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

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

    Science.gov (United States)

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

    2016-05-01

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

  4. 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.

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

    International Nuclear Information System (INIS)

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

  6. 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.

  7. Drug agglomeration and dissolution--what is the influence of powder mixing?

    Science.gov (United States)

    Kale, Kamakshi; Hapgood, Karen; Stewart, Peter

    2009-05-01

    This study determined the influence of mixing speed and time on the dissolution and deagglomeration of a micronised, poorly water-soluble drug, indomethacin, in lactose interactive mixtures. Mixing occurred in a Turbula mixer; dissolution studies were performed using the USP paddle method, and the extent of deagglomeration was determined using modelling strategies and laser diffraction particle sizing of the powder mixtures. During low energy mixing at low rates and short mixing times, dissolution profiles showed an unusual flat asymptote indicating incomplete extents of dissolution caused by agglomerates that did not readily disperse in the dissolution medium. The study showed that increasing both speed and time of mixing increased the extent of dissolution and deagglomeration of the indomethacin powder. Nonlinear least squares modelling of the dissolution data using a sigmoidal equation provided estimates of the extent and rate of dissolution. Mixing speed and time had a much greater influence on the extent of dissolution which was controlled by deagglomeration than on the initial dissolution rate which was related to dispersed indomethacin. While some deagglomeration did occur at higher mixing energies, the deagglomeration of the indomethacin was not complete with only about 58-80% of indomethacin particles overlapping with the primary indomethacin particle size distribution. The significant outcome of this study was that mixing conditions have a major influence on the mixing quality, especially in areas where agglomerate characteristics influence performance. PMID:19347972

  8. Measurement of drug agglomerates in powder blending simulation samples by near infrared chemical imaging.

    Science.gov (United States)

    Li, Weiyong; Woldu, Abraham; Kelly, Richard; McCool, Jim; Bruce, Rick; Rasmussen, Henrik; Cunningham, John; Winstead, Denita

    2008-02-28

    This research note describes a powder blending simulation study conducted using 20-mL scintillation vials and a bench-top rotating mixer on a scale of 2g for each sample. In order to investigate the impact of mean particle size and size distribution on blending behavior of an active pharmaceutical ingredient (API), the drug substance was separated into sieve fractions using the US standard sieves of 60, 80, 100, 200, and 325mesh. Each of the fractions was mixed with two excipients (hydroxypropyl methylcellulose and microcrystalline cellulose) for up to 20min. Then the blending samples were analyzed by a near infrared chemical imaging (NIR-CI) system. The NIR-CI system was able to measure API particles/domains (agglomerates) at 0.001mm(2) and above within a 11.2mmx9.0mm field of view. It was found that blends prepared with larger API particles (60-200 mesh) contain agglomerated API domains > or =0.1mm(2). The blends prepared with finer API particles (< or =325 mesh) show the characteristics of a randomized mixing. This simple and effective method can be used for evaluation of blending behavior for APIs in formulation development. PMID:17951017

  9. 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.

  10. 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.

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Polettini, Alessandra; Pomi, Raffaella; Valente, Mattia

    2004-01-01

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

  13. 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.

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

    Directory of Open Access Journals (Sweden)

    E. Haxhiaj

    2012-01-01

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

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

    International Nuclear Information System (INIS)

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

  16. 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.

  17. 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.

  18. 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.

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

    Science.gov (United States)

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

    2014-03-15

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

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

    Science.gov (United States)

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

    2015-12-01

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

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

    Science.gov (United States)

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

    2014-03-15

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

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

    Directory of Open Access Journals (Sweden)

    Adriana REVEIU

    2012-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Keya Chakraborty

    2011-06-01

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

  5. Monitoring and Sampling Strategy for (Manufactured) Nano Objects Agglomerates and Aggregates (NOAA); Potential Added Value of the NANODEVICE Project

    NARCIS (Netherlands)

    Brouwer, D.H.; Lidén, G.; Asbach, C.; Berges, M.; Tongeren, M. van

    2014-01-01

    The production of nanomaterials and nano-enabled products is associated with the potential for workers' exposure to (manufactured) nano-objects' agglomerates and aggregates (NOAA). Workplace air monitoring studies have been conducted to assess the actual exposure; however, the methods and strategies

  6. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-31

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

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

    Science.gov (United States)

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

    2016-01-01

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

  9. 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.

  10. 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

  11. 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

  12. 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

  13. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-07-01

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

  15. Elasticity and electrical properties of porous bodies described as an agglomerate-of-spheres

    Science.gov (United States)

    Höpfinger, H.; Winsel, A.

    The phenomenological characterization of a sintered, pressed or electrolytically produced porous body as an 'agglomerate-of-spheres' (AOS), estimated by the properties of their connections — the so-called necks—, was used to predict its break-force, elasticity and resistance. To this, the previous theoretical description of the AOS could be expanded by the definition of an ideal AOS. Furthermore, it could be shown, that the behaviour of the AOS is re-inforced by the relation of the radii of the sphere and neck. The description of the mechanical properties correlates well in the case of elasticity and breaktension with data of experiments at the University of Kassel with PbO 2-electrodes. The theoretically predicted values of the electrical properties are about a hundred times smaller than the experimental ones. This may be caused by the material-specific circuit capacity used for the PbO 2, since there are no data concerning the stoichiometric variance of the oxygen phase width in the neck region. An attempt to approach to real electrodes is only a trial, which, for the first time, takes experimental data into consideration. The lack of dependable material-specific sizes of lead dioxide is still the greatest inaccuracy in comparison with experimental data.

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

    International Nuclear Information System (INIS)

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

  17. 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.

  18. 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.

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

    International Nuclear Information System (INIS)

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

  20. 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.

  1. 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.

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

    International Nuclear Information System (INIS)

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

  3. 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...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-11-12

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

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

    Directory of Open Access Journals (Sweden)

    Tošić Dragutin

    2005-01-01

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

  6. 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.

  7. 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.

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

    Science.gov (United States)

    Feng, Jinming; Wang, Jun; Yan, Zhongwei

    2014-03-01

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

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

    International Nuclear Information System (INIS)

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

  10. 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.

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

    OpenAIRE

    LAURA CISMAŞ; ANDRA MICULESCU; MARIA OŢIL

    2010-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

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

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

    Science.gov (United States)

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

    2012-05-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-03-01

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

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

    International Nuclear Information System (INIS)

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

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

    Institute of Scientific and Technical Information of China (English)

    庞维强; 樊学忠; 胥会祥; 李勇宏

    2009-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    HRMA PR

    2008-12-18

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

  18. 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.

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

    International Nuclear Information System (INIS)

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

  20. 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

  1. Application of synchrotron radiation X-ray computed tomography to investigate the agglomerating behavior of TiB{sub 2} particles in aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Fei; Mao, Feng; Chen, Zongning; Han, Jingyu; Yan, Guangyuan [Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Wang, Tongmin, E-mail: tmwang@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Cao, Zhiqiang, E-mail: caozq@dlut.edu.cn [Laboratory of Special Processing of Raw Materials, Dalian University of Technology, Dalian 116024 (China)

    2015-02-15

    Highlights: • SR-CT was a powerful tool to investigate the TiB{sub 2} distribution in Al-TiB{sub 2} in situ composites. • Three kinds of agglomerations frequently present in the composites. • Agglomerations formed via the diffused atoms reacting with intermediate products. • The composites containing agglomerations show a much reduced ductility. - Abstract: Agglomeration of reinforcing particles has a number of deleterious effects on the properties of in situ metal matrix composites (MMCs). In order to better understand this phenomenon, the agglomerating behavior of TiB{sub 2} particles in aluminum based in situ MMCs was investigated using synchrotron radiation X-ray computed tomography (SR-CT) and field emission scanning electron microscope (FESEM). SR-CT was shown to be a powerful tool for visualizing and quantifying the three-dimensional (3D) features within the composites. Based on the SR-CT and FESEM results, a formation mechanism of the flaky agglomerates, flocculent agglomerates and clusters of coarse TiB{sub 2} particles, which are most frequently presented in the in situ Al/TiB{sub 2} composite, has been proposed. The mechanism shows that the formation of these three kinds of agglomerates can be attributed to three parallel processes, i.e. diffusing titanium atoms reacting with AlB{sub 2}, aluminum melt directly reacting with emulsified salt, diffusing boron atoms reacting with TiAl{sub 3}, respectively. Moreover, the mechanism may shed some light on how to design better processing techniques for obtaining homogenous particle distribution in in situ Al/TiB{sub 2} composites in the future.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-15

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

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

    OpenAIRE

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    R. Bhaskara Rao

    1996-12-01

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

  5. 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.

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

    Science.gov (United States)

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

    2016-03-01

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

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

    Science.gov (United States)

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

    2016-04-01

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

  8. 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)

  9. 河南省产业集聚区空间规划引导研究%Industrial Agglomeration Area Spatial Planning Guide Research of Henan Province

    Institute of Scientific and Technical Information of China (English)

    黄向球; 高耸; 麻永建; 牛艳华

    2014-01-01

    河南省产业集聚区作为推动区域城镇化进程和产业结构升级转型的重要动力,其发展建设深刻影响着河南省区域人口的集聚及城镇化进程。产业集聚区空间规划是促进产业集聚区有序发展的前提,通过对河南省产业集聚区前期规划进行深入研究,找出目前产业集聚区空间规划存在的问题,提出“五规合一”和“产城融合”的规划理念,以此为基础,在产业引导、空间统筹引导和政策措施引导3个层面破解产业集聚区空间规划存在的问题,同时为产业集聚区空间规划提供方法与策略的引导,促进产业集聚区与城市的深度融合,保证产业集聚区的健康发展。%Henan industrial agglomeration area as the important driving force of promote regional urbanization and industrial structure transformation,its development affects profound the regional population agglomeration and urbanization of Henan Province. The industrial agglomeration area spatial planning is the prerequisite for promoting the orderly development of industrial agglomeration area,through the pre-planning of industrial agglomeration area in Henan Province in-depth research to identify current problems about industrial agglomeration area spatial planning,propose the idea of the joining together of five rules and production integration of the city,on this basis, adopt the industrial guidance,space overall guidance and policy measures to crack the problems of spatial planning about industrial agglomeration area,as well as industrial agglomeration area provide space planning methods and strategies guidance,and promoting the depth of integration between industrial agglomeration area and the city,to ensure the healthy development of industrial agglomeration area.

  10. 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.

  11. 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

  12. 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.

  13. What drives employment growth of Canadian Businesses? A Fresh Look at Indicators of Agglomeration Economies when Competition and Diversity Matter

    DEFF Research Database (Denmark)

    Wang, Cong; Steiner, Bodo

    2014-01-01

    This study investigates indicators of external scale economies in Canada for the period 2004-11. Accounting for firm-level external scale forces, we explore the extent to which external scale economies impact employment growth. Our analysis focuses on three factors: the impact of external scale...... economies accounting for Marshallian specialization and Jacobs diversity, competition by industry, and related and unrelated firm varieties in terms of employment and sales. Results accounting for non-linearity between employment growth and agglomeration suggest that in the short run, during the period 2004...

  14. 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.

  15. 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)

  16. Agglomeration and Collection of Fine Secondary Phases in Flowing Suspensions Utilizing Resonant Ultrasonic Fields.

    Science.gov (United States)

    Tolt, Thomas Lester

    1990-01-01

    A novel separation process based on a forced coincident excitation at ultrasonic frequencies in fluid filled tubes has been studied and developed for the agglomeration and collection of fine secondary phases in flowing suspensions. Under appropriate conditions, acoustic radiation forces can act to drive second phase inclusions to the nodes (or antinodes) of a stationary sound field and trap them there with a strength which can exceed the hydrodynamic drag exerted on the particles by a flowing fluid matrix. A review of the theoretical development of the acoustic forces acting on and between inclusions in a sound field is presented. The fields generated in a water bath using a lead zirconate -lead titanate piezoelectric disk acting a source of ultrasonic waves a short distance in front of a parallel reflector and in later experiments utilizing simple cylindrical chambers are compared to calculated stationary fields in Fabry-Perot laser resonators with parallel, plane finite mirrors. It is suggested that diffraction at the transducer and reflector surfaces is responsible for the creation of guided standing waves which have a nonuniform transverse distribution of acoustic velocity and pressure along nodal planes of minimum pressure spaced at intervals equal to one half of the acoustic wavelength in the fluid. This leads to the existence of transverse components in the acoustic radiation force in addition to an axially directed force which act to collect fine secondary phases into thin lens-shaped zones. Broadband piezoelectric transducers bonded to the ends of fluid filled glass and aluminum tubes (up to 4 cm in diameter and 25 cm in length, and ranging from 0.9 to 2 mm in wall thickness) were driven with continuous a.c. voltages at unique frequencies in the range of 0.35 to 1.4 Mhz to obtain a forced coincidence response in which the flexural vibrations of the tube wall are matched in phase and geometry with higher-order acoustic duct modes in the liquid. This

  17. Anthropogenic heat fluxes over Moscow agglomeration and other Russian and world cities

    Science.gov (United States)

    Belova, Iya; Ginzburg, Alexander

    2010-05-01

    Urbanization, particularly with respect to its sustainability, remains to be a great challenge in all regions of the world. Urbanization has an influence on soils, hydrology, and climate, these changes have effect on global climate, pollution, increase of anthropogenic greenhouse gases in the earth's atmosphere and human health. Thus anthropogenic heat flux is an important factor for estimation of development of global climate. The simple formula for anthropogenic heat fluxes (AHF) was proposed in the EGU General Assembly 2008 presentation [1] AHF = k × PD × EC, were PD is urban population density and EC is total energy consumption per capita. It was estimated that two of the world megacities - Seoul and Moscow - have the highest AHF values - 83 and 56 W/m2 correspondently. In presented paper it was studied the reasons of such high anthropogenic heat fluxes within Moscow region as well as AHF over the major Russian cities. It was shown that main reason of this circumstance is the administrative divisions in Moscow region. Moscow is ringed by Moscow circle motor road. Accordingly the city has sharply defined boundaries and densely populated residential suburbs are cut off and don't included in Moscow city administrative area. It was constructed the special graph to illuminate why Moscow city has such a high anthropogenic heat factor and how much Moscow agglomeration AHF could be if consider not only Moscow city itself but also the nearest suburb towns. Using the data from World Bank [2] and Russian governmental statistic agency [3] anthropogenic heat fluxes for Russian cities with population more than 500 000 were estimated. Energy consumption data for different Russian regions were calculated by special routine using in the Web-atlas [4]. This research is supported by RAS Fundamental Research Project 'Influence of anthropogenic heat fluxes and aerosol pollution on heat balance and climate of urbanized areas'. Other results of this project is presented in paper [5

  18. 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

  19. Sources of organic pollution in particulate matter and soil of Silesian Agglomeration (Poland): evidence from geochemical markers.

    Science.gov (United States)

    Fabiańska, Monika J; Kozielska, Barbara; Konieczyński, Jan; Kowalski, Adam

    2016-06-01

    The exact input of particular sources to polycyclic aromatic hydrocarbons (PAHs) concentrations in urban and industrial agglomerations is still not well recognized. The major breakthrough is possible using geochemical markers. In the air aerosol and soil samples from areas located in the direct influence of industry/traffic in Silesian Agglomeration (Poland), PAHs and other organic compounds were analyzed, including geochemical markers (biomarkers) and polar compounds from fossil fuels and biomass. Gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS) were applied to investigate the composition of particulate matter and soil extracts. The results suggest that the predominant source of PAHs is fossil fuel. The presence and distribution of steranes, pentacyclic triterpenoids (i.e., hopanes and moretanes) and alkyl PAHs point to traffic emissions and fossil fuel combustion, mainly bituminous coal for power and heat purposes, as the main source of PAHs in the region. Moreover, the presence of fossil fuel biomarker in particulate matter and soil extracts from a rural site, previously considered to be free of organic pollution, requires a cautious interpretation for PAHs results. Apart from the fossil fuel, also other sources of contamination were identified in particulate matter extracts by their markers: phenols and levoglucosan for biomass and diisopropylnaphthalenes for printing materials combustion. The absence of polar biomass combustion indicators in soil extracts might be related to their higher reactivity. PMID:26362678

  20. 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.

  1. Fractal and agglomeration behavior in Gd and Sm doped CeO2 nano-crystalline powders

    International Nuclear Information System (INIS)

    Nanocrystalline Gd, Sm doped ceria powders were synthesized by a combustion technique, using glycine as the fuel. These powders, after calcination at 600 oC, were characterized by powder X-ray diffraction and were found to be phase pure. The crystallite sizes, as calculated from X-ray line broadening were in the range of 11-13 nm, which were in close agreement with those obtained from the SAXS studies. The TEM studies also showed the particle sizes to be in the range of 10-15 nm. These powders showed a high surface area as observed from BET technique. The extent and nature of agglomeration was studied by a particle size analyzer. The fractal behaviour of these nano-sized powders prepared by combustion synthesis, has also been investigated by small angle X-ray scattering technique. Results showed that the powders contain aggregates with rough fractal surfaces above a length scale of 20 nm. These parameters of the powders and their agglomerates were found to play a significant role in the sintering behavior

  2. 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.

  3. 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.

  4. 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).

  5. 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.

  6. Theoretical model for surface diffusion driven Ni-particle agglomeration in anode of solid oxide fuel cell

    Science.gov (United States)

    Gao, Sheng; Li, Jiayu; Lin, Zijing

    2014-06-01

    The agglomeration of Ni particles in nickel-yttria stabilized zirconia (YSZ) anode is an important degradation mechanism for the solid oxide fuel cell and is widely believed to be driven by surface diffusion. This work aims to develop a quantitative model to describe the agglomeration kinetics. The model treats the anode as a system of random packing Ni and YSZ particles. Surface diffusion occurs between the connected Ni particles of different sizes characterized by two representative radii, but is influenced by the YSZ network. The Fick's law for diffusion, the Gibbs-Thomson relation for vacancy concentration and the coordination number theory for percolating Ni network are employed in the mathematical derivation. The growth kinetics is expressed as an analytical function consisting of two model parameters, one for the Ni-particle size distribution and the other for the influence of the YSZ backbone. The model is in excellent agreement with the available experiments. The influence of the YSZ backbone is further considered to obtain a model with just one fitting parameter. The one-parameter model is also in good agreement with the experiments and the fundamental physics for the Ni-particle growth is therefore believed to be well characterized.

  7. 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

  8. Engineering development of advanced physical fine coal cleaning for premium fuel applications. Task 6 -- Selective agglomeration laboratory research and engineering development for premium fuels

    Energy Technology Data Exchange (ETDEWEB)

    Moro, N.; Jha, M.C.

    1997-06-27

    The primary goal of this project is the engineering development of two advanced physical fine coal cleaning processes, column flotation and selective agglomeration, for premium fuel applications. The project scope included laboratory research and benchscale testing on six coals to optimize these processes, followed by the design, construction, and operation of a 2 t/hr process development unit (PDU). The project began in October, 1992, and is scheduled for completion by September 1997. This report represents the findings of Subtask 6.5 Selective Agglomeration Bench-Scale Testing and Process Scale-up. During this work, six project coals, namely Winifrede, Elkhorn No. 3, Sunnyside, Taggart, Indiana VII, and Hiawatha were processed in a 25 lb/hr continuous selective agglomeration bench-scale test unit.

  9. 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

    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......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...

  10. Diamond-like-carbon nanoparticle production and agglomeration following UV multi-photon excitation of static naphthalene/helium gas mixtures

    Science.gov (United States)

    Walsh, A. J.; Tielens, A. G. G. M.; Ruth, A. A.

    2016-07-01

    We report the formation of nanoparticles with significant diamond character after UV multi-photon laser excitation of gaseous naphthalene, buffered in static helium gas, at room temperature. The nanoparticles are identified in situ by their absorption and scattering spectra between 400 and 850 nm, which are modeled using Mie theory. Comparisons of the particles' spectroscopic and optical properties with those of carbonaceous materials indicate a sp3/sp2 hybridization ratio of 8:1 of the particles formed. The particle extinction in the closed static (unstirred) gas-phase system exhibits a complex and quasi-oscillatory time dependence for the duration of up to several hours with periods ranging from seconds to many minutes. The extinction dynamics of the system is based on a combination of transport features and particle interaction, predominantly agglomeration. The relatively long period of agglomeration allows for a unique analysis of the agglomeration process of diamond-like carbon nanoparticles in situ.

  11. DOES EU-INTEGRATION CHANGE AGGLOMERATION PROCESS? THE IMPACT OF EU MEMBERSHIP PROCESS ON THE CITY-SIZE DISTRIBUTION OF TURKEY

    Directory of Open Access Journals (Sweden)

    Engin Sorhun

    2013-02-01

    Full Text Available This paper aims to reveal the eventual impacts of European Union (EU membership process and other conventional factors on the city-size distribution of a candidate country (Turkey. I can state main results as follows: Analyzing from different estimation methods the direct effect of the EU reforms on agglomerating forces rather than congesting forces are revealed to be dominant for Turkey. However, the main impact of the EU membership process has positive but modest coefficient that indicate the weak willingness of the country for EU reforms.Keywords: Economic itegration, agglomeration, city-size distribution, EU, Turkey.JEL Classification: F15, F22, R12, R23

  12. 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.

  13. 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

  14. 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

  15. 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)

  16. 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)

  17. Stretched Exponential Change of Magnetic Weight of Magnetite Ferrofluid: Distribution of Energy Barrier for Agglomeration of Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Daeseong; Kim, Hackjin [Chungnam National University, Taejeon (Korea, Republic of)

    2015-01-15

    Magnetic nanoparticles usually agglomerate reversibly under magnetic field. Magnetophoretic transport demonstrates the possibilities of the biomedical applications such as intercellular manipulation of magnetic nanoparticles for imaging or drug delivery. Magnetization of ferro fluid occurs by Neel and Brownian mechanism and aggregation of nanoparticles. We have recently reported the magnetization of magnetite ferro fluid studied by measuring the change of magnetic weight. The stretched exponential behaviors have been observed for the samples of different concentrations under various magnetic fields. When we study the transmission change of the fluid as like in Refs 2 and 12, the single or double exponential decay is observed, which suggests that the particle movement in the fluid is affected by diffusion but the structural relaxations of aggregates cause the stretched exponential dynamics.

  18. 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.

  19. 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.

  20. Influence of agglomeration and specific lung lining lipid/protein interaction on short-term inhalation toxicity.

    Science.gov (United States)

    Wohlleben, Wendel; Driessen, Marc D; Raesch, Simon; Schaefer, Ulrich F; Schulze, Christine; Vacano, Bernhard von; Vennemann, Antje; Wiemann, Martin; Ruge, Christian A; Platsch, Herbert; Mues, Sarah; Ossig, Rainer; Tomm, Janina M; Schnekenburger, Jürgen; Kuhlbusch, Thomas A J; Luch, Andreas; Lehr, Claus-Michael; Haase, Andrea

    2016-09-01

    Lung lining fluid is the first biological barrier nanoparticles (NPs) encounter during inhalation. As previous inhalation studies revealed considerable differences between surface functionalized NPs with respect to deposition and toxicity, our aim was to investigate the influence of lipid and/or protein binding on these processes. Thus, we analyzed a set of surface functionalized NPs including different SiO2 and ZrO2 in pure phospholipids, CuroSurf(TM) and purified native porcine pulmonary surfactant (nS). Lipid binding was surprisingly low for pure phospholipids and only few NPs attracted a minimal lipid corona. Additional presence of hydrophobic surfactant protein (SP) B in CuroSurf(TM) promoted lipid binding to NPs functionalized with Amino or PEG residues. The presence of the hydrophilic SP A in nS facilitated lipid binding to all NPs. In line with this the degree of lipid and protein affinities for different surface functionalized SiO2 NPs in nS followed the same order (SiO2 Phosphate ∼ unmodified SiO2 < SiO2 PEG < SiO2 Amino NPs). Agglomeration and biomolecule interaction of NPs in nS was mainly influenced by surface charge and hydrophobicity. Toxicological differences as observed in short-term inhalation studies (STIS) were mainly influenced by the core composition and/or surface reactivity of NPs. However, agglomeration in lipid media and lipid/protein affinity appeared to play a modulatory role on short-term inhalation toxicity. For instance, lipophilic NPs like ZrO2, which are interacting with nS to a higher extent, exhibited a far higher lung burden than their hydrophilic counterparts, which deserves further attention to predict or model effects of respirable NPs. PMID:26984182

  1. 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.

  2. 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.

  3. 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

  4. 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.)

  5. An Experimental Investigation of Agglomeration with One and Two Nozzle Atomisation%单双喷嘴雾化凝聚的实验研究

    Institute of Scientific and Technical Information of China (English)

    Justin Nijdam; GUO Baoyu; Maritza Valencia-Bejarano; Timothy Langrish

    2004-01-01

    Water-droplet size and velocity measurements were taken throughout two different sprays produced by a single nozzle and two nozzles pointed towards each other. The aim of this investigation was to understand the manner in which the motion of the droplets in a spray leads to agglomeration of these droplets. It appears that the inertia of the droplets plays an important role in the redistribution of droplets throughout a spray. Larger droplets tend to concentrate at the outer portions of the spray, because they are able to maintain their radial momentum farther downstream of a nozzle, while the smaller droplets follow the airflow more closely and thus collect in the core of the spray. Agglomeration can result from both turbulent collisions and collisions due to the relative velocities of the droplets. The difference between the agglomeration rates in the sprays from a single nozzle and two-nozzles pointed towards each other was difficult to resolve in these experiments, although the results suggest that the outer portions of both sprays should be investigated more closely for evidence of agglomeration.

  6. 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

  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. 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.

  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. 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."

  11. 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.

  12. 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.

  13. 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. PMID:24772079

  14. Influence of agglomeration of cerium oxide nanoparticles and speciation of cerium(III) on short term effects to the green algae Chlamydomonas reinhardtii

    International Nuclear Information System (INIS)

    Highlights: • Phosphate-dispersed CeO2 NP did not affect photosynthetic yield in C. reinhardtii. • Agglomerated CeO2 NP slightly decreased photosynthetic yield. • Cerium(III) was shown to affect photosynthetic yield and intracellular ROS level. • Slight effects of CeO2 NP were caused by dissolved Ce3+ ions present in suspensions. • Wild type and cell wall free mutant of C. reinhardtii showed the same sensitivity. - Abstract: Cerium oxide nanoparticles (CeO2 NP) are increasingly used in industrial applications and may be released to the aquatic environment. The fate of CeO2 NP and effects on algae are largely unknown. In this study, the short term effects of CeO2 NP in two different agglomeration states on the green algae Chlamydomonas reinhardtii were examined. The role of dissolved cerium(III) on toxicity, its speciation and the dissolution of CeO2 NP were considered. The role of cell wall of C. reinhardtii as a barrier and its influence on the sensitivity to CeO2 NP and cerium(III) was evaluated by testing both, the wild type and the cell wall free mutant of C. reinhardtii. Characterization showed that CeO2 NP had a surface charge of ∼0 mV at physiological pH and agglomerated in exposure media. Phosphate stabilized CeO2 NP at pH 7.5 over 24 h. This effect was exploited to test CeO2 NP dispersed in phosphate with a mean size of 140 nm and agglomerated in absence of phosphate with a mean size of 2000 nm. The level of dissolved cerium(III) in CeO2 NP suspensions was very low and between 0.1 and 27 nM in all tested media. Exposure of C. reinhardtii to Ce(NO3)3 decreased the photosynthetic yield in a concentration dependent manner with EC50 of 7.5 ± 0.84 μM for wild type and EC50 of 6.3 ± 0.53 μM for the cell wall free mutant. The intracellular level of reactive oxygen species (ROS) increased upon exposure to Ce(NO3)3 with effective concentrations similar to those inhibiting photosynthesis. The agglomerated CeO2 NP caused a slight decrease of

  15. 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

  16. The factors that explain the major agglomeration of the industry of high technology in the north border of Mexico: the case of Matamoros and Reynosa

    Directory of Open Access Journals (Sweden)

    Jorge Alberto Pérez Cruz

    2014-01-01

    Full Text Available In the last three decades the geographical distribution of manufacturing change substantially, prompting new concentrations, particularly in the high tech industry. In this sense, the aim of this study is to know and analyze from the perspective of pecuniary and technological externalities factors that explain the change in the agglomeration of high-tech manufacturing. To do so,a questionnaire was applied to 55 manufacturing facilities located in Matamoros andReynosa in Tamaulipas. The results indicate that the highest concentration of high-tech industry has been motivated mainly by the geographic location of the municipalities, access to unskilled labor and cheap availability of urban infrastructure, among others. This means that there is no evidence for the pecuniary and technological externalities determine the agglomeration of high-tech industry in these cities.

  17. THE INFLUENCE OF AGGLOMERATIONS CONCERNING THE GENERATION OF EXTERNALITIES FOR ENTERPRISEShttp://dx.doi.org/10.5585/riae.v9i2.1673

    Directory of Open Access Journals (Sweden)

    Bruno Tavares

    2010-11-01

    Full Text Available This article aims to identify, through theoretical analysis, the influence agglomerations have in the generation of firm externalities. Hence, the idea is established by demonstrating that productive clusters are different, although largely ignored in a vast number of articles and in the development of public policies; which can be identified by the various existing typologies (Pedersen, 1997, Van Dijk; Sverrisson, 2003, SUZIGAN 2006. The study was based on the theory of productive clusters and in national and international empirical papers. Consequently, we conclude the agglomerations do not have equal potential to generate externalities, rather, it is expected the contribution that companies can receive is dependent upon the characteristics of each.  In addition, we propose a few approaches for companies, government agents and public policy makers.

  18. Multiple-Locus Departures from Panmictic Equilibrium within and between Village Gene Pools of Amerindian Tribes at Different Stages of Agglomeration

    OpenAIRE

    Smouse, Peter E.; Neel, James V.; Liu, Wanda

    1983-01-01

    A comparative analysis of departures from multiple-locus Hardy-Weinberg equilibrium is presented for a set of four tribal Indian groups (the Yanomama, Makiritare, Wapishana and Ticuna) from the lowlands of South America. These tribes span a range of agglomeration and acculturation from the most traditional, swidden horticulturalists to frontier townspeople. The small-group social organization typical of traditional horticulturalists leads to substantial departures from tribal panmixia, as man...

  19. 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.

  20. 1D versus 3D quantum confinement in 1-5 nm ZnO nanoparticle agglomerations for application in charge-trapping memory devices.

    Science.gov (United States)

    El-Atab, Nazek; Nayfeh, Ammar

    2016-07-01

    ZnO nanoparticles (NPs) have attracted considerable interest from industry and researchers due to their excellent properties with applications in optoelectronic devices, sunscreens, photocatalysts, sensors, biomedical sciences, etc. However, the agglomeration of NPs is considered to be a limiting factor since it can affect the desirable physical and electronic properties of the NPs. In this work, 1-5 nm ZnO NPs deposited by spin- and dip-coating techniques are studied. The electronic and physical properties of the resulting agglomerations of NPs are studied using UV-vis-NIR spectroscopy, atomic force microscopy (AFM), and transmission electron microscopy (TEM), and their application in metal-oxide-semiconductor (MOS) memory devices is analyzed. The results show that both dip- and spin-coating techniques lead to agglomerations of the NPs mostly in the horizontal direction. However, the width of the ZnO clusters is larger with dip-coating which leads to 1D quantum confinement, while the smaller ZnO clusters obtained by spin-coating enable 3D quantum confinement in ZnO. The ZnO NPs are used as the charge-trapping layer of a MOS-memory structure and the analysis of the high-frequency C-V measurements allow further understanding of the electronic properties of the ZnO agglomerations. A large memory window is achieved in both devices which confirms that ZnO NPs provide large charge-trapping density. In addition, ZnO confined in 3D allows for a larger memory window at lower operating voltages due to the Poole-Frenkel charge-emission mechanism. PMID:27232717

  1. The influence of coal-associated trace elements on sintering and agglomeration of a model coal mineral mixture / M.V. Nel.

    OpenAIRE

    Nel, Marika Verita

    2009-01-01

    A series of experiments was conducted to investigate the potential influence of selected inorganic compounds on sintering and agglomeration of a model mineral mixture. The minerals and inorganic compounds were chosen based on the constituents found in coal. The study simulated ash formation processes in the temperature range of 500 °C to 1000 DC. The mineral mixture consisted of kaolinite, quartz, pyrite, siderite, calcite, Ti02 and magnesite in a fIxed ratio. The mixture was ...

  2. 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.

  3. 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)

  4. Theory and Practice in Deep Integration of Provincial Urban Agglomeration:A Case of Zhongyuan Urban Agglomeration%省域城市群深度整合的理论与实践研究——以中原城市群为例

    Institute of Scientific and Technical Information of China (English)

    王发曾; 闫卫阳; 刘静玉

    2011-01-01

    In the first half of the 21 st century, urban agglomerations on various spatial scales will play an important role in China's socio-economic development, and provincial urban agglomerations are bound to become the major basis of the province development strategy. Based on the study on the cohesion and outreach of Zhongyuan urban agglomeration, the paper deepens the integration theory of provincial urban agglomeration. The conclusion as follows: 1 ) Cohesion means to create the modem metropolitan area, and build core growth pole to drive the rapid development of urban agglomeration. Outreach means to create modem provincial urban system, and build regional support system to host the healthy development of urban agglomeration. 2) The Zhongyuan urban agglomeration comprises the four industrial zones and developmental axes. 3 ) Zhongyuan urban agglomeration cohesions in the municipal district of Zhengzhou-Kaifeng, which can be divided into five functional regions. And the construction of industrial zone in Zhengzhou-Kaifeng should be gone firstly as the important ingredient of the key functional region. 4) Zhongyuan urban agglomeration outreaches in the urban system of Henan Province,which has two intensive projects of building platform for the urbanism and brought its whole functions into play.And 5 ) in the strategic planning of Zhongyuan Economic Zone, Zhongyuan urban agglomeration is still the major distraction slabs, which integration, cohesion and outreach will give important support for Zhongyuan Economic Zone and play a key role on national development.%21世纪前半叶,各种空间尺度的城市群将在我国经济社会发展中扮演重要角色,省域城市群必然成为省(区)发展战略的主要牵引板块.一方面,省域城市群的深度整合迫切需要城市群理论与方法的指导与支撑;另一方面,城市群整合理论需要通过城市群建设实践进行提炼与升华,并在实践中进一步验证.通过中原城市群初步整

  5. Thermal desorption and recycling of volatile selective binders used in solid wastes deashing; Desorption thermique et recyclage d'agglomerants selectifs volatils utilises en decendrage de residus solides

    Energy Technology Data Exchange (ETDEWEB)

    Bensakhria, A.; Sajet, P.; Antonini, G. [Universite de Technologie de Compiegne, Centre de Recherches de Royallieu UMR 6067, Genie des Procedes Industriels, 60 - Compiegne (France)

    2001-07-01

    A pilot unit for the deashing of coal tailings by selective agglomeration and recovery of the binder/water mixture by azeotropic desorption of binders has been tested. The effect of different experiment parameters on the deashing efficiency, on the recovery and recycling of the binding agent have been tested. A 90% deashing level with a 94% recovery of the carbonaceous matter has been obtained with a recycling level of about 82% for the agglomerating agent. (J.S.)

  6. Luminescence in CaSO4 : Dy phosphor - dependence on grain agglomeration, sintering temperature, sieving and washing

    Science.gov (United States)

    Lakshmanan, A. R.; Jose, M. T.; Ponnusamy, V.; Vivek Kumar, P. R.

    2002-02-01

    In the recently developed high-sensitive CaSO4 : Dy phosphor, sieving before the high-temperature sintering treatment has successfully eliminated particle agglomeration during subsequent sintering, and has further enhanced its thermostimulated luminescence (TSL) sensitivity to γ-rays. The reduction in TSL sensitivity of higher sized grains observed earlier following the procedure of sieving after sintering has also more or less vanished. Maximum TSL sensitivity is seen after sintering around 700°C, whereas maximum photoluminescent (PL) sensitivity is seen after sintering around 325°C. While the observed increase in TSL sensitivity (by 30%) with increasing sintering temperature in the range 325-700°C is explained on the basis of diffusion of Dy3+ ions from the surface to the whole volume of the grains (0-75 µm), the drastic decrease (by a factor of 3) in PL sensitivity with increasing sintering temperature is explained on the basis of change in the Dy3+ environment on the grain surface perhaps due to oxygen incorporation. Washing with water and acetone, which affect mainly the surface traps, enhances the PL sensitivity of CaSO4 : Dy slightly; however, it does not influence TSL sensitivity very significantly. Grinding reduces PL in general, but no such trend was noticed in TSL which supports the conclusion that PL originates mainly from surface traps since grinding affects mainly the grain surface. However, the sharp reduction in TSL and PL sensitivities observed at 400°C indicates that an unusual process takes place near that sintering temperature.

  7. 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.

  8. Estimation Terrestrial Net Primary Productivity Based on CASA Model: a Case Study in Minnan Urban Agglomeration, China

    International Nuclear Information System (INIS)

    Net Primary Productivity (NPP) is a key component of the terrestrial carbon cycle. The research of net primary productivity will help in understanding the amount of carbon fixed by terrestrial vegetation and its influencing factors. Model simulation is considered as a cost-effective and time-efficient method for the estimation of regional and global NPP. In the paper, a terrestrial biosphere model, CASA (Carnegie Ames Stanford Approach), was applied to estimate monthly NPP in Minnan urban agglomeration (i.e. Xiamen, Zhangzhou and Quanzhou cities) of Fujian province, China, in 2009 and 2010, by incorporating satellite observation of SPOT Vegetation NDVI data together with other climatic parameters and landuse map. The model estimates average annual terrestrial NPP of Minnan area as 16.3 million Mg C. NPP decreased from southwest to the northeast. The higher NPP values exceeding 720 gC·m− 2·a −1 showed in North Zhangzhou city and lower values under 500 gC·m− 2·a −1 showed in the some areas of northeast Quanzhou city. Seasonal variations of NPP were large. It was about 45% of the total annual NPP in the three months in summer, and the NPP values were very low in winter. From 2009 to 2010, the value of annual NPP showed a slightly decrease trend, approximately 7.8% because the annual temperature for 2010 decline 13.6% compared with 2009 in despite of an increase in rainfall of about 34.3%. The results indicate that temperature was a main limiting factor on vegetation growth, but water is not a limiting factor in the rainy area

  9. 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.

  10. 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

  11. Effects of temperature and initial molar ratio of Na2O to Al2O3 on agglomeration of fine AI(OH)3 seed in synthetic Bayer solution

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Fine AI(OH)3 crystals were aggregated from supersaturated aluminate solution in the batch reaction tanks.By means of laser particle size analyzer and scanning electron microscopy,the influences of temperature and initial molar ratio of Na2O to A12O3 (αK) on agglomeration of fine seed in Bayer process were investigated.The results show that agglomeration is almost finished in 8 h,and seeds with size less than 2 μm are easily aggregated together,and almost disappear in 8 h under the optimal process conditions.In the aluminate solution with the same moderate initial αK,when the reaction temperature reaches 75 ℃,the secondary nucleation does not occur,and the effect of agglomeration is better.And at the same reaction temperature,when the initial αK is 1.62,the initial supersaturation of aluminate solution is moderate,the binders on the surfaces of the seed are enough to maintain the agglomeration process,and the agglomeration degree is better.From SEM images,agglomeration mainly occurs in the fine particles,the combinations among the fine particles are loose and the new formed coarse crystal shapes are irregular.

  12. 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.

  13. 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。

  14. 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

  15. 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

  16. Nanoparticle agglomerates in magnetoliposomes

    International Nuclear Information System (INIS)

    Magnetoliposomes consist of vesicles composed of a phospholipid membrane encapsulating magnetic nanoparticles. These systems have several important applications, such as in MRI contrast agents, drug and gene carriers, and cancer treatment devices. For all of these applications, controlling the number of encapsulated magnetic nanoparticles is a key issue. In this work, we used a magneto-optical technique to obtain information about the efficiency of encapsulation, the number of nanoparticles encapsulated per liposome and also about the formation of the nanoparticle structures. The parameters studied included the effect of the duration of sonication, the presence of cholesterol in the liposome membrane, as well as time-related stability. For the liposomal vesicles prepared in this work, we found between 35 and 300 nanoparticles encapsulated per liposome, depending on the experimental conditions, consisting of small linear chains of nanoparticles, basically trimers and tetramers. The methodology developed might be useful for the investigation and improvement of the properties of several magnetic nanocarrier systems.

  17. Skills, Agglomeration and Segmentation

    OpenAIRE

    Tomoya Mori; Alessandro Turrini

    2000-01-01

    We investigate the role of skill heterogeneity in explaining location patterns induced by pecuniary externalities (Krugman (1991)). In our setting, sellers with higher skills perform better in the marketplace, and their sales are larger. Selling to distant locations leads to lower sales because of both (pecuniary) transport costs and communication costs that reduce the perceived quality of goods. A symmetry-breaking result is obtained: symmetric configurations cannot be stable, and regional i...

  18. Agglomeration and aid

    NARCIS (Netherlands)

    S. Brakman (Steven); J.H. Garretsen (Harry); J.G.M. van Marrewijk (Charles)

    2007-01-01

    textabstractA key issue in development economics is the explanation of core-periphery patterns around the world. Combining this issue with that of analyzing unilateral transfers (e.g. foreign aid) points in the direction of the use of New Economic Geography (NEG) models which, so far, has not been d

  19. 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.

  20. 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.

  1. Agglomerated nanoparticles of hydrous Ce(IV) + Zr(IV) mixed oxide: Preparation, characterization and physicochemical aspects on fluoride adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Abir; Chakrabarti, Sharadindra; Biswas, Krishna; Ghosh, Uday Chand, E-mail: ucghosh@yahoo.co.in

    2014-07-01

    Hydrous Ce(IV)–Zr(IV) oxide (Ce/Zr ~ 1:1, mol/mol) (HCZMO) prepared by simple chemical precipitation was nanoparticles (60–70 nm) agglomerate with irregular surface morphology. The BET surface area, pore volume and pHzpc were estimated to be 185.04 m² g⁻¹, 0.1219 cm³ g⁻¹ and 5.8 (±0.2), respectively. Investigation of fluoride adsorption over HCZMO from its aqueous phase at an optimized pH ~ 6.0 showed that the adsorption kinetics and equilibrium data described, respectively, the pseudo-second order equation (R² = 0.98–0.99) and the Langmuir isotherm (R² > 0.99) very well. Values of the computed Arrhenius activation energy, Ea (1.16 kJ mol⁻¹), Langmuir monolayer capacity, θ (19.5 mg g⁻¹), D–R adsorption energy, ED–R (15.05 kJ mol⁻¹) and isosteric heat of reaction, ΔHr (0.518 kJ mol⁻¹) suggested that the fluoride has high affinity for homogeneous HCZMO surface for adsorption. Evidences appeared from the equal distribution co-efficient values and too well Langmuir isotherm fit. The fluoride adsorption reactions at 298–313 K with HCZMO were spontaneous (ΔG⁰ = negative) despite endothermic nature (ΔH⁰, kJ mol⁻¹ = +3.53, +4.04), owing to the increase of entropy (ΔS⁰, J mol⁻¹ K⁻¹ = +12.4, 13.8). More than 95% fluoride was released from F⁻-HCZMO (24.8 mg F⁻ g⁻¹) by 1.0 M NaOH, confirming the ion-exchange adsorption mechanism inclining to chemisorption. 1 g HCZMO per liter of a groundwater (F⁻: 4.40 mg L⁻¹) can reduce fluoride level below 1.5 mg L⁻¹ in batch treatment.

  2. 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

  3. 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.

  4. Detection of selected pathogens in ticks collected from cats and dogs in the Wrocław Agglomeration, South-West Poland

    OpenAIRE

    Król, Nina; Obiegala, Anna; Pfeffer, Martin; Lonc, Elżbieta; Kiewra, Dorota

    2016-01-01

    Background Tick-borne infections are no longer confined to rural areas, they are documented with increasing frequency in urban settlements across the world. They are known to cause diseases in humans as well as in their companion animals. Methods During a period of 2 years, from January 2013 until December 2014, ticks were collected from dogs and cats in 18 veterinary clinics in the Wrocław Agglomeration, Poland. In total, 1455 ticks were found on 931 pets: 760 domestic dogs and 171 cats. For...

  5. 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。

  6. 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

  7. A $\\sim$32-70 K formation temperature range for the ice grains agglomerated by comet 67P/Churyumov-Gerasimenko

    CERN Document Server

    Lectez, S; Mousis, O; Picaud, S; Altwegg, K; Rubin, M; Salazar, J M

    2015-01-01

    Grand Canonical Monte Carlo simulations are used to reproduce the N$_2$/CO ratio ranging between 1.7 $\\times$ 10$^{-3}$ and 1.6 $\\times$ 10$^{-2}$ observed {\\it in situ} in the Jupiter family comet 67P/Churyumov-Gerasimenko by the ROSINA mass spectrometer aboard the Rosetta spacecraft, assuming that this body has been agglomerated from clathrates in the protosolar nebula. Simulations are done using an 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$_2$ in proportions corresponding to those expected for the protosolar nebula. By assuming that 67P/Churyumov-Gerasimenko agglomerated from clathrates, our calculations suggest the cometary grains must have been formed at temperatures ranging between $\\sim$31.8 and 69.9 K in the protosolar nebula to match the N$_2$/CO ratio measured by the ROSINA mass spectrometer. The presence of clathrates in Jupiter family comets could then explain the potential ...

  8. 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.

  9. 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.

  10. 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).

  11. Assessment of agglomeration, co-sedimentation and trophic transfer of titanium dioxide nanoparticles in a laboratory-scale predator-prey model system

    Science.gov (United States)

    Gupta, Govind Sharan; Kumar, Ashutosh; Shanker, Rishi; Dhawan, Alok

    2016-01-01

    Nano titanium dioxide (nTiO2) is the most abundantly released engineered nanomaterial (ENM) in aquatic environments. Therefore, it is prudent to assess its fate and its effects on lower trophic-level organisms in the aquatic food chain. A predator-and-prey-based laboratory microcosm was established using Paramecium caudatum and Escherichia coli to evaluate the effects of nTiO2. The surface interaction of nTiO2 with E. coli significantly increased after the addition of Paramecium into the microcosm. This interaction favoured the hetero-agglomeration and co-sedimentation of nTiO2. The extent of nTiO2 agglomeration under experimental conditions was as follows: combined E. coli and Paramecium > Paramecium only > E. coli only > without E. coli or Paramecium. An increase in nTiO2 internalisation in Paramecium cells was also observed in the presence or absence of E. coli cells. These interactions and nTiO2 internalisation in Paramecium cells induced statistically significant (p < 0.05) effects on growth and the bacterial ingestion rate at 24 h. These findings provide new insights into the fate of nTiO2 in the presence of bacterial-ciliate interactions in the aquatic environment. PMID:27530102

  12. 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.

  13. Assessment of agglomeration, co-sedimentation and trophic transfer of titanium dioxide nanoparticles in a laboratory-scale predator-prey model system.

    Science.gov (United States)

    Gupta, Govind Sharan; Kumar, Ashutosh; Shanker, Rishi; Dhawan, Alok

    2016-01-01

    Nano titanium dioxide (nTiO2) is the most abundantly released engineered nanomaterial (ENM) in aquatic environments. Therefore, it is prudent to assess its fate and its effects on lower trophic-level organisms in the aquatic food chain. A predator-and-prey-based laboratory microcosm was established using Paramecium caudatum and Escherichia coli to evaluate the effects of nTiO2. The surface interaction of nTiO2 with E. coli significantly increased after the addition of Paramecium into the microcosm. This interaction favoured the hetero-agglomeration and co-sedimentation of nTiO2. The extent of nTiO2 agglomeration under experimental conditions was as follows: combined E. coli and Paramecium > Paramecium only > E. coli only > without E. coli or Paramecium. An increase in nTiO2 internalisation in Paramecium cells was also observed in the presence or absence of E. coli cells. These interactions and nTiO2 internalisation in Paramecium cells induced statistically significant (p < 0.05) effects on growth and the bacterial ingestion rate at 24 h. These findings provide new insights into the fate of nTiO2 in the presence of bacterial-ciliate interactions in the aquatic environment. PMID:27530102

  14. 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.

  15. 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.

  16. 浙江省科技人才集聚的政策效应%Policy Effect of Scientific and Technological Talent Agglomeration in Zhejiang Province

    Institute of Scientific and Technical Information of China (English)

    盛亚; 于卓灵

    2015-01-01

    通过现场访谈和问卷调查收集数据,对浙江省现有人才政策对科技人才集聚的影响进行了实证分析。结果显示:人才安全政策、人才激励政策、人才选拔和使用政策以及人才评价政策属于“强势影响政策”;人才吸引政策、人才流动政策和人才培养政策属于“中势影响政策”。最后提出了浙江省进一步有效实现区域人才集聚的政策建议。%Using the data from field interview and questionnaire ,this paper empirically analyzes the influence of the existing talent policies in Zhejiang province on sci‐tech talent agglomeration.The result shows as follows :the policies of "talent security" ,"talent motivation" ,"talent se‐lection and management" and "talent evaluation"are called "the policy of strong influence" ;the policies of "talent attraction" "talent flow"and"talents training" are called "the policies of general influence".Finally ,it gives some policy suggestions for promoting the agglomeration of sci‐tech talent effectively .

  17. 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

  18. 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

  19. 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

  20. 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。

  1. 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.

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

    Institute of Scientific and Technical Information of China (English)

    李俊玮; 常远; 高菠阳

    2015-01-01

    As the key subject of the 12th five-year development plan,the importance of urban agglomerations in national economy development is rising. This study established an industry radiation force model and radiation fault zones model to quantify the radiation force and area of specific industry of core cities in urban agglomerations. Based on data from 2000 to 2012,the study measured the real estate radiation force and range of Beijing to its surrounding cities in Beijing-Tianjin-Hebei. Results show that the fault zone is shrinking and is affected by five factors,including the mechanisms of urban agglomerations,macro-economy operation, industrial characteristics,government policies,and the supply and demand sides of real estate market. This study provides method to quantify the industry radiation force and scope and facilitates urban government’s policy making for industrial development.%作为“十二五”规划重点发展对象,城市群在我国经济发展中占据重要地位。通过构建城市产业辐射力模型和城市产业辐射断裂带模型,测算城市群中核心城市特定产业的辐射能力与范围,并利用2000~2012年数据实证测算京津冀城市群中北京市对周边地区房地产业的辐射影响。研究结果表明产业辐射断裂带呈微缩趋势,影响因素源于城市群机理、宏观经济背景、行业特征、政府政策、供需双方行为5个方面。该研究为测量城市群内城市特定产业的辐射力强度与范围提供了理论方法;有助于政府部门全面掌握城市产业辐射力表现,为科学制定城市产业发展规划提供参考与依据。

  3. SPATIAL LINKAGE PATTERN OF TOURISM ECONOMY IN THE WANJIANG URBAN AGGLOMERATION%皖江城市群旅游经济空间联系格局

    Institute of Scientific and Technical Information of China (English)

    沈惊宏; 陆玉麒; 周玉翠; 尹贻梅

    2012-01-01

    在皖江城市群作为承接长三角产业转移示范区背景下及区域交通网络化、区域旅游一体化发展的新形式下,对皖江城市群旅游经济联系和影响范围研究就显得必要。以该地区10城市的旅游经济联系为主线,以界定旅游中心节点、测算旅游经济联系量和场强模型为手段,构建皖江城市群旅游圈。研究表明:以合肥和芜湖为双核的皖江城市群大旅游圈,其内部分为3个次旅游经济圈,北部以合肥为中心,包括六安区域、滁州和含巢湖整个水面的大部分区域的合肥旅游圈;西南以安庆为中心、池州为副中心,含铜陵一部分地区的安庆旅游圈;东南以芜湖为中心、宣城为副中心,包括马鞍山和部分巢湖区域、部分铜陵区域的芜湖旅游圈。最后提出了3个旅游经济圈发展的旅游规划建议。%Under the Wanjiang Urban Agglomeration becoming demonstration zones of facilitating industrial transfer of the Yangtze River Delta, and the new situation of the regional transportation network and the integration of regional tourism development, it is a fundamental requirement to set up a new cooperation mechanism of tourism development and coordinate regional sustainable tourism development for tourism e- conomy in the Wanjiang Urban Agglomeration. Thus,it is necessary to study on tourism economic linkage and areas of influence in the Wanjiang Urban Agglomeration. Tourism economic linkage among the 10 cities was regarded as the main line of the thesis. The author defined tourism center node, calculated strength of tourism economic linkage and influence areas of field-strength, and constructed tourism circles of the Wanjiang Urban Agglomeration. The results showed that Wanjiang city group tourism circle centering on dualcore of Hefei and Wuhu was divided into three tourism economic circles. They were Hefei tourism circle centering on Hefei in the northern of it,including parts of

  4. Colloidal Instability Fosters Agglomeration of Subvisible Particles Created by Rupture of Gels of a Monoclonal Antibody Formed at Silicone Oil-Water Interfaces.

    Science.gov (United States)

    Mehta, Shyam B; Carpenter, John F; Randolph, Theodore W

    2016-08-01

    In this study, we investigated the effect of ionic strength (1.25-231 mM) on viscoelastic interfacial gels formed by a monoclonal antibody at silicone oil-water interfaces, and the formation of subvisible particles due to rupture of these gels. Rates of gel formation and their elastic moduli did not vary significantly with ionic strength. Likewise, during gel rupture no significant effects of ionic strength were observed on particle formation and aggregation as detected by microflow imaging, resonance mass measurement, and size exclusion chromatography. Subvisible particles formed by mechanical rupturing of the gels agglomerated over time, even during quiescent incubation, due to the colloidal instability of the particles. PMID:27422087

  5. 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.

  6. Agglomeration Control of Ultrafine Y2 O3-ZrO2 and (MgO, Y2 O3)-ZrO2 Powders Synthesized by Coprecipitation Process

    Institute of Scientific and Technical Information of China (English)

    MA Yalu; ZHANG Yu; ZHENG Junping

    2005-01-01

    Chemical coprecipitation was used to produce ultrafine and easily sinterable Y2O3-stabilized and (Y2O3,MgO)-stabilized ZrO2 powders. Six precipitation processes for preparation of ZrO2-based ultrafine powders were designed separately, meanwhile different techniques used to control the agglomeration formation were proposed. By means of TEM, SEM, Raman spectroscopy and IR spectroscopy, the mechanisms of agglomeration control in the precipitation processes and post-precipitation and drying process were investigated. The experimental results show that adding appropriate anion surface active agents (such as PAA1460) or polymer (PEG1540 matching with PEG200) in aqueous solution systems during precipitation processes could reinforce charge effect and location effect for gel particles interface. Adding wetting agents to wet gels washing with distilled water during drying process could change interface structure of gel particles and decrease surface tension between gel particles. The agglomeration control in the precipitation, post-precipitation and drying processes had remarkable influence on the characteristics of powders. By adding various macromolecules in the processes, the agglomeration state could be controlled efficiently, and the characteristics of powders were improved.

  7. 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

  8. 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.

  9. 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。

  10. 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

  11. 大型城市群建筑中的公共空间合理性设计%Public Space Rationality Design of Large Urban Agglomeration

    Institute of Scientific and Technical Information of China (English)

    戴菲

    2015-01-01

    通过对大型城市群建筑的公共空间合理性设计,提高大型城市群建筑公共空间合理设计水平,提高建筑空间的利用率.在增大城市居民居住区的绿化率的同时,实现城市建筑的绿色节能,设计的空间利用方案采用多参量自回归分析方法,空间设计中考虑的影响因素如光照、温度、湿度、绿化植被等影响,分析了大型城市公共空间设计的评价指标,给出空间优化设计拟合模型,研究结果表明,采用该设计方案,大型城市群建筑公共空间得到合理利用,实现节能环保,利用效率最高,改善人居环境.%Through the reasonable design of public space in the large city group, improve the public space of large urban ag-glomeration design level, improve the utilization of building space. Increased urban residential district greening rate at the same time, to achieve the green energy saving of urban construction, design space utilization scheme using multi parameter regression analysis method, space design in consideration of the influence factors such as light, temperature, humidity, green vegetation effect, analyzes the assessment index of large urban public space design, gives the optimum design of space fitting model, results show that the design scheme, the large scale urban agglomeration in building public space get reasonable use, to achieve energy saving and environmental protection, has the highest efficiency, improve the living envi-ronment.

  12. Analysis on Ecological Footprint of the Urban Agglomeration in Pearl River Delta%珠三角城市群生态足迹分析

    Institute of Scientific and Technical Information of China (English)

    钟义; 程欢; 彭晓春; 白中炎; 董家华; 陈志良; 李泰儒; 洪鸿加

    2012-01-01

    [目的]计算和分析2009年殊三角城市群生态足迹.[方法]以珠三角9个市为研究区,运用生态足迹计算模型对2009年珠三角市生态足迹和生态安全进行计算,定量分析珠三角区域生态环境现状和可持续发展状况.[结果]珠三角城市群除了建筑用地和林地稍显生态盈余外,其他4种土地类型均处于生态赤字状态,特别是可耕地和化石燃料用地,存在明显的生态赤字.[结论]珠三角生物资源消费水平和能源消费水平较高,应采取多种措施减少生态赤字,以使得发展方式向更加可持续性的方向转变.%[Objective] The research aimed to calculate and analyze ecological footprint of the urban agglomeration in Pearl River Delta in 2009, [Method] 9 cities in Pearl River Delta as research zone, by using calculation model of the ecological footprint, ecological footprint and security of the urban agglomeration in Pearl River Delta were calculated. Current situation and sustainable development condition of the ecological environment in Pearl River Delta were quantitatively analyzed. [Result] Except construction land and forest land, other 4 kinds of lands were all in ecological deficit statuses in Pearl River Delta. Especially arable land and fossil fuel land had obvious ecological deficit. [Conclusion] Biological resource consumption level and energy consumption level in Pearl River Delta were higher. We ought to take a variety of measures to reduce ecological deficit to make development manner turn toward sustainable direction.

  13. 城市物流网络空间结构集聚扩散演化模型%Agglomeration and dispersion evolution model for spatial structure of urban logistics network

    Institute of Scientific and Technical Information of China (English)

    付江月; 张锦; 陈以衡; 陈刚

    2016-01-01

    以城市物流网络空间结构为研究对象,运用复杂网络方法构建了以经济机制为驱动、网络总成本最小为目标,考虑网络规模动态变化、空间距离限制等条件的拓展加权BA模型(无标度网络模型),对其集聚扩散演化进行了研究;并设计了演化算法,利用MATLAB进行了仿真试验和分析.研究结果表明:集聚经济是城市物流网络空间结构集聚形态(集聚演化)的形成机制,集聚不经济是分散、均衡形态(扩散演化)的形成机制;演化中集聚机制的作用更明显;物流节点比通道更能体现集聚扩散演化特征.所构建的模型能够模拟和分析城市物流网络空间结构集聚扩散演化的过程与特征,并揭示经济性演化机制的作用机理.%Taking spatial structure of urban logistics network as research object,to investigate its agglomeration and dispersion evolution,an extended and weighted BA model was established based on complex network method.The evolution model was driven by economic mechanism and established to minimize the total cost of urban logistics network.The proposed model also took dynamic change of network scale and spatial distance into consideration.Evolutionary algorithm was designed and MATLAB was used to conduct numerical simulation and analysis.The results show that agglomeration economy is the driving force of agglomeration evolution of urban logistics spatial pattern.While agglomeration diseconomy is the driving power for the dispersion (or deconcentration,sprawl) and balance of urban logistics spatial pattern.Effect of agglomeration economy is more obvious in the evolving process,and the logistics nodes can reflect the polarization-sprawl evolution characteristics better than the logistics channels.The constructed model can simulate and analyze the agglomeration and dispersion evolution process and characteristics of urban logistics spatial network structure and to uncover mechanism of economic motive power.7

  14. 总部经济集聚区协同发展与对策研究%A Study on the Synergetic Development of Agglomeration Zone in Headquarters Economy

    Institute of Scientific and Technical Information of China (English)

    王举颖; 金乐

    2014-01-01

    总部经济集聚区内企业间价值链互动与合作,获得更多的价值链高端价值,发挥总部经济的集聚优势,从而推动总部经济集聚区协同发展。在综合性总部经济集聚区协同发展中,不同产业企业总部之间的协同和支柱产业与现代服务业的协同并存,而在特色性总部经济集聚区协同发展中,同一产业链企业总部之间的协同和旧产业路径依赖与新产业培育的协同并存。从政府、企业、中介协作发展角度,制定相应的总部经济集聚区协同发展对策,要求在强化企业总部间协同创新和企业主体作用的基础上,加强政府政策引导和保障体制建设,并完善社会中介服务支持体系的有力支撑。%The interaction and cooperation of value chain can obtain higher value among enterprises in the agglomeration zone of headquarters economy ,make best use of the agglomeration advantages of head-quarters economy ,and promote the synergetic development of headquarters economy agglomeration .The coordination of the corporate headquarters from different industries and the coordination of pillar industries and modern service industries coexist in the synergetic development of comprehensive headquarters eco-nomic agglomeration .In the synergetic development of the distinctive headquarters economic agglomera-tion ,the coordination of the corporate headquarters from the same industrial chain ,and the coordination of the old industrial path dependence and the new industry incubation coexist .From the perspective of gov-ernments ,enterprises and intermediary cooperative development , the corresponding measures should be introduced for the synergetic development of headquarters economic agglomeration .Based on strengthe-ning the innovation of the corporate headquarters and the leading role of enterprises ,the government's poli-cy guidance and support system construction should be guaranteed ,and the social intermediary

  15. 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。

  16. Public Service,Labor Migration and Industrial Agglomeration-A Research of the Impact of One-sided Urbanization Policy on Industrial Agglomeration%公共服务、劳动力流动与产业集聚--兼论片面城市化政策对产业集聚的影响

    Institute of Scientific and Technical Information of China (English)

    赵祥

    2014-01-01

    The paper makes an analysis on the impact of the supply level of urban public services on industrial agglomeration from the perspective of labor mobility. It finds that the local governments at all levels in China implement the one-sided urban-ization policy,which brings about the inadequate supply of basic public services such as public health,compulsory education and social security,etc. Moreover,the migrating population is difficult to enjoy the same basic public services as registered pop-ulation in cities, which raises the hidden costs of inter-regional labor migration, reduces inter-regional mobility of labor, and hinders the efficient industrial agglomeration in space. Therefore,it is necessary to strive to promote the process of urban-ization, which aims to make migrant workers become true citizens, in order to improve the level of industrial geographic ag-glomeration and spatial allocation efficiency of economic resources in China.%文章从劳动力流动的角度分析了城市公共服务供给水平对产业集聚的影响,认为我国各级地方政府所实施的片面城市化政策导致政府对公共卫生、义务教育和社会保障等基本公共服务供给不足。流动人口难以享受到与户籍人口同等的基本公共服务,提高了劳动力区际流动的隐性成本,降低了劳动力的区际流动性,阻碍了我国产业在空间上的高效集聚。因此,为提高我国产业的地理集聚水平和经济资源的空间配置效率,有必要着力推动以流动人口市民化为核心的城市化进程。

  17. 中国城市群形成发育的政策保障机制与对策建议%Urban Agglomerations Formation and Development in China: Policy Guarantee Mechanism, Countermeasures and Suggestions

    Institute of Scientific and Technical Information of China (English)

    方创琳; 张舰

    2011-01-01

    Urban agglomeration with the most energies and potential, is a core district in China' s economic development pattern in the future, and is the key development zone and the optimized development zone in Major Function Oriented Zoning in China. Additionally, it is also the important direction for future urban development and acts as strategic support, growth pole and core node in national pattern of productivity location. According to some new characteristics and problems existing in the process of China' s urban agglomeration formation and development, this paper constructs organization and coordination guarantee mechanism (OCGM) , public finance guarantee mechanism ( PFCM), laws and regulations guarantee mechanism ( LRGM) and resources and environment guarantee mechanism (REGM) for urban agglomeration sustainable development respectively from four aspects of power, financial resources, legal force and ability. Furthermore, this paper puts forward some countermeasures and methods to speed up healthy urban agglomeration development, which includes the following: making certain state centralized management department and establishing state-level management committee of urban agglomeration coordinated development and cross-city coordinated organization for industrial development; constructing public finance mechanism and public finance reserve system; pushing the work of legislation for integrated development of urban agglomerations, constituting convention for cooperation of urban agglomerations and amending Urban and Rural Planning Act in which adds contents of urban agglomeration planning; putting forward Methods of Urban Agglomeration Planning Making, Examine and Approve, Regulations on Implementation and Management of Urban Agglomeration Planning and Technical Guidelines for Urban Agglomeration Planning, and establishing professional certified system to guide its scientific planning and strengthen capacity of resources and environment guarantee and sustainable

  18. Influences of land cover types, meteorological conditions, anthropogenic heat and urban area on surface urban heat island in the Yangtze River Delta Urban Agglomeration.

    Science.gov (United States)

    Du, Hongyu; Wang, Duoduo; Wang, Yuanyuan; Zhao, Xiaolei; Qin, Fei; Jiang, Hong; Cai, Yongli

    2016-11-15

    Urban heat islands (UHIs) reflect the localized impact of human activities on thermal fields. In this study, we assessed the surface UHI and its relationship with types of land, meteorological conditions, anthropogenic heat sources and urban areas in the Yangtze River Delta Urban Agglomeration (YRDUA) with the aid of remote sensing data, statistical data and meteorological data. The results showed that the UHI intensity in YRDUA was the strongest (0.84°C) in summer, followed by 0.81°C in autumn, 0.78°C in spring and 0.53°C in winter. The daytime UHI intensity is 0.98°C, which is higher than the nighttime UHI intensity of 0.50°C. Then, the relationship between the UHI intensity and several factors such as meteorological conditions, anthropogenic heat sources and the urban area were analysed. The results indicated that there was an insignificant correlation between population density and the UHI intensity. Energy consumption, average temperature and urban area had a significant positive correlation with UHI intensity. However, the average wind speed and average precipitation were significantly negatively correlated with UHI intensity. This study provides insight into the regional climate characteristics and a scientific basis for city layout. PMID:27424113

  19. 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

    2016-07-01

    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.

  20. 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 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.

  1. 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.

  2. 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.

  3. Transfer-free graphene synthesis on sapphire by catalyst metal agglomeration technique and demonstration of top-gate field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Miyoshi, Makoto, E-mail: miyoshi.makoto@nitech.ac.jp; Arima, Yukinori; Kubo, Toshiharu; Egawa, Takashi [Research Center for Nano Device and Advanced Materials, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Mizuno, Masaya [Research Center for Nano Device and Advanced Materials, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Department of Frontier Materials, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Soga, Tetsuo [Department of Frontier Materials, Nagoya Institute of Technology, Nagoya 466-8555 (Japan)

    2015-08-17

    Transfer-free graphene synthesis was performed on sapphire substrates by using the catalyst metal agglomeration technique, and the graphene film quality was compared to that synthesized on sputtered SiO{sub 2}/Si substrates. Raman scattering measurements indicated that the graphene film on sapphire has better structural qualities than that on sputtered SiO{sub 2}/Si substrates. The cross-sectional transmission microscopic study also revealed that the film flatness was drastically improved by using sapphire substrates instead of sputtered SiO{sub 2}/Si substrates. These quality improvements seemed to be due the chemical and thermal stabilities of sapphire. Top-gate field-effect transistors were fabricated using the graphene films on sapphire, and it was confirmed that their drain current can be modulated with applied gate voltages. The maximum field-effect mobilities were estimated to be 720 cm{sup 2}/V s for electrons and 880 cm{sup 2}/V s for holes, respectively.

  4. Agglomeration, Returns to Education and Level of Wages: A Comparative Analysis of Service and Manufacture in China%产业集聚对教育回报与工资水平的影响——基于我国服务业与制造业集聚的比较分析

    Institute of Scientific and Technical Information of China (English)

    韩帅; 孙浦阳; 张诚

    2012-01-01

    This paper investigates the effects of service agglomeration and manufacture agglomeration on level of wages in Chinese cities based on the Marshall's "three-pillar'doctrineof agglomeration. Our empirical study uses a panel data from 2003 to 2009 including 31 provinces nd 19 industries. After investigating the effects of agglomeration on level of wages, we go further to study the effects of agglomeration on wage returns to education, through which we can distinguish the two kinds of MAR agglomeration effects labor market pool and knowledge spillover. At the same time, we compare the different influence on wage of service and manufacture agglomeration. The results suggest that service agglomeration can rise the own industry wage but cannot changes the returns to education, which means that MAR agglomeration affect the wage through knowledge spillover in service sector. To the contrary, manufacture agglomeration may bring down the own industry wage but raise the returns to education, which means that MAR agglomeration af fect the wage through the labor market pool in manufacture sector. The results also suggest the level of wages raised by agglomeration more significantly in middle and west of China.%根据马歇尔集聚效应理论,使用我国31个省级行政区19个行业20032009年的面板数据进行实证研究,探索了服务业与制造业集聚对工资的影响;之后,通过引入教育指标,进一步验证集聚对教育的工资回报的影响,这样区分了马歇尔集聚中劳动力市场共享和知识外溢对工资的影响机制。研究发现,服务业集聚对教育回报无显著影响,但是却显著提高了本行业的工资水平,体现了马歇尔集聚中的技术外溢效应;相反,制造业集聚会压低本行业工资水平.但却显著提高了该行业教育回报,体现了劳动力市场共享效应。中西部地区的产业集聚对工资的提高作用更加明显。

  5. 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)

  6. 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.

  7. The Affect of Tacit Knowledge Transmission to the Creative Industry Agglomeration%隐性知识传递对于我国创意产业集聚的影响

    Institute of Scientific and Technical Information of China (English)

    连玮佳; 李健

    2009-01-01

    由于隐性知识的"粘滞性"特点,企业为了隐性知识的顺利传递通常选择以产业集聚的形式发展,因此隐性知识传递一直被认为是产业集聚的重要因素.进一步分析隐性知识的传递对于创意产业集聚这一新兴产业的影响.基于我国创意产业的发展实际,认为隐性知识传递是我国创意产业集聚的本质原因,并对创意产业集群中的隐性知识进行两种不同的分类.%Because of the sticky characteristic of tacit knowledge, enterprises have to choose industry agglomeration in order to transfer tacit knowledge smoothly, therefore tacit knowledge transmission is supposed to be an important reason for industry agglomeration. After that, we discuss the impact of tacit knowledge transmission on creative industry. Based on the development of creative industry in our country, we put forward that tacit knowledge transmission is the basic reason for creative industry agglomeration in our country, and draw two kinds of classifications of the tacit knowledge transmission in an industry cluster.

  8. 构建长株潭数字城市群的理论分析与实施建议%Theoretical analysis and proposals for the construction of Chang-Zhu-Tan digital urban agglomeration

    Institute of Scientific and Technical Information of China (English)

    汪海; 蒋涤非

    2012-01-01

    通过阐述长株潭数字城市群的建设背景、概念,运用博弈理论,建立了政府与项目公司之间的博弈模型,讨论特许权期、项目公司建设成本、补偿费用等因素之间的关系,提出了构建长株潭数字城市群的基本框架和实施建议,提供建设长株潭数字城市群的发展思路.%The construction background and concepts of Chang - Zhu - Tan urban digital agglomeration was described and analyzed, and a game model for government and project company was set up under game theory. The relationship among the concession period, the project company construction cost and the compensation fees were discussed. Changsha - Zhuzhou -Xiangtan digitel urban agglomeration was proposed. The basic frame and implementation proposals, development idlea of Changsha - Zhuzhou - Xiangtan urban agglomeration were given.

  9. 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

  10. Mechanisms and Empirical Study of Pollution Dividend and Pollution Agglomeration%污染红利与污染集聚的机理与实证

    Institute of Scientific and Technical Information of China (English)

    张乐才

    2011-01-01

    文章用污染要素的替代效应与成本效应对污染集聚的形成机理进行了分析,研究结果说明污染红利会带来污染集聚.首先,污染替代效应会导致污染密集型产业成为主导产业;其次,污染成本效应一方面会导致单个企业排污加大,另一方面还会扩大污染密集型企业的数量;第三,污染替代效应和成本效应作为污染总效应的分支,二者的作用是累加的,不会互相抵消.为了检验该研究结论的正确性,本文用内蒙古工业规模效应、工业结构效应、工业科技效应指标对该省废气排放总量进行了回归分析,结果支持了上述研究结论.首先,有利于把污染当作红利使用的工业规模效应与工业科技效应均促进了废气排放的增加;其次,抑制把污染当作红利使用的工业结构效应则促进了废气排放的减少.因此,我国彻底治理环境污染是一项长期的任务,我们在加大产业结构调整的过程中,尤应加大对污染密集型产业的抑制.%This article analyzes the mechanism of how pollution dividend makes pollution agglomeration by applying the method of using alternative effectiveness and cost effectiveness included in pollution elements, the research shows that the pollution dividend brings about the pollution agglomeration. Firstly, the alternative effectiveness of pollution makes the pollution intensive industry as the leading industry; Secondly, the cost effectiveness of pollution makes the firm increasing sewage on one hand, on other hand ,because of the role of cost effectiveness of pollution , the number of pollution intensive industry firms are increased; Thirdly, both as the branch of pollution elements, the utilities of cost effectiveness and alternative effectiveness don't balance out but accumulate for each other. In order to test the correctness of this conclusion, the article makes a regression analysis by using the effects of industrial scale, industrial structure

  11. Engineering a new class of thermal spray nano-based microstructures from agglomerated nanostructured particles, suspensions and solutions: an invited review

    International Nuclear Information System (INIS)

    From the pioneering works of McPherson in 1973 who identified nanometre-sized features in thermal spray conventional alumina coatings (using sprayed particles in the tens of micrometres size range) to the most recent and most advanced work aimed at manufacturing nanostructured coatings from nanometre-sized feedstock particles, the thermal spray community has been involved with nanometre-sized features and feedstock for more than 30 years. Both the development of feedstock (especially through cryo-milling, and processes able to manufacture coatings structured at the sub-micrometre or nanometre sizes, such as micrometre-sized agglomerates made of nanometre-sized particles for feedstock) and the emergence of thermal spray processes such as suspension and liquid precursor thermal spray techniques have been driven by the need to manufacture coatings with enhanced properties. These techniques result in two different types of coatings: on the one hand, those with a so-called bimodal structure having nanometre-sized zones embedded within micrometre ones, for which the spray process is similar to that of conventional coatings and on the other hand, sub-micrometre or nanostructured coatings achieved by suspension or solution spraying. Compared with suspension spraying, solution precursor spraying uses molecularly mixed precursors as liquids, avoiding a separate processing route for the preparation of powders and enabling the synthesis of a wide range of oxide powders and coatings. Such coatings are intended for use in various applications ranging from improved thermal barrier layers and wear-resistant surfaces to thin solid electrolytes for solid oxide fuel cell systems, among other numerous applications. Meanwhile these processes are more complex to operate since they are more sensitive to parameter variations compared with conventional thermal spray processes. Progress in this area has resulted from the unique combination of modelling activities, the evolution of

  12. Influence of Impurity on Radiative Properties of Randomly Oriented Cluster Agglomerates%掺杂对随机取向团簇粒子辐射特性的影响

    Institute of Scientific and Technical Information of China (English)

    类成新; 冯东太; 吴振森

    2011-01-01

    The influence of impurity on the radiative properties of randomly oriented cluster agglomerates was mainly analyzed. The equivalent complex refractive index of aerosols containing different volume fractions of amorphous carbon was obtained by Bruggeman effective medium theory. The radiative characteristic quantities were calculated based on the discrete dipole approximation method, such as the phase function, extinction, absorption and scattering efficiency factor, single-scattering albedo and asymmetrical parameter of randomly oriented cluster agglomerates. The influence of the impurity on the radiative properties of randomly oriented cluster agglomerates was mainly discussed. The results indicate that the influence of the impurity on the radiative properties of randomly oriented cluster agglomerates is obvious, and it varies with the size parameters of the randomly distributed cluster agglomerates. This work is important for the study of radiative characteristics of aerosols with a mixture of various chemical compositions and their climatic effects.%利用Bruggeman有效介质理论得到了占有不同体积份额杂质的团簇粒子的等效复折射率.采用离散偶极子近似方法对包含有不同化学成分的随机取向团簇粒子的散射相函数、消光、吸收、散射效率因子、单次散射反照率以及不对称因子等辐射特性参量进行了数值计算,深入探讨了掺杂量对随机取向团簇粒子辐射特性的影响.研究表明,掺杂对随机取向团簇粒子的辐射特性产生显著的影响,并且此影响随着粒子尺度参量的变化而变化.这一工作对研究多种化学成分组成的混合气溶胶的辐射及气候效应具有重要科学价值.

  13. 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。

  14. Ecological sanitation of the industrial agglomeration area of Leipzig/Bitterfeld/Halle/Merseburg. Preliminary study. Compilation of data for the evaluation of the environmental situation. Umweltsanierung des Grossraumes Leipzig/Bitterfeld/Halle/Merseburg. Vorstudie. Erfassung der vorhandenen Daten zur Beurteilung der Umweltsituation

    Energy Technology Data Exchange (ETDEWEB)

    1990-07-08

    The study contains the data required for an ecological sanitation concept for the industrial agglomeration area of Leipzig and Halle. Data were acquired and compiled on the following subjects: (1) Site availability, quantity and quality of environmentally relevant data for the agglomeration area, (2) lacking data or unreliable data that require further information; (3) immediate remedy measures derived from these data, listed according to priority. (BBR).

  15. [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.

  16. 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.

  17. 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。

  18. 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

  19. 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

  20. Research on the Collaborative Development Obstacle and Implementation Mechanism of Large Urban Agglomerations%大城市群协同发展障碍及实现机制研究

    Institute of Scientific and Technical Information of China (English)

    陈耀; 汪彬

    2016-01-01

    大城市群是一国工业化、城市化发展到一定时期的产物,是进入成熟经济阶段的空间组织形态,也是世界各国参与国际竞争的重要地域单元。当前我国大城市群存在着“大而散”“大而不强”的问题,根源于大城市群内部缺乏“协同效应”,协同的障碍主要在于内部差异性大、行政区划分割及级别不对等、财税分灶体制等。大城市群要着力从基础设施、要素市场、产业分工、公共服务、生态环保等方面积极推进内部一体化。在协同创新机制设计上要明确一个“核心”,发挥市场主体功能,重视社会组织力量,建立利益共享和利益补偿机制,完善行政主体首长联席会议制度。%Large urban agglomeration is a certain period of product with the development of industrialization and urbanization development of a country, is the economic spatial organization form which enters the mature stage, is also an important regional unit that countries around the world participate in international competition. Nowadays large urban agglomeration has problems such as“big but dispersion”“big but not strong”. These problems rooted in lack of“synergistic effect”in the internal of large urban agglomerations, the main collaborative obstacle depends on the internal differences, the administrative division and partition of the level unequal, the focal points system of finance and tax system, etc. In order to push the internal integration, large urban agglomeration needs to focus on the infrastructure, the factor market, the industrial division of labor, public services, and ecological and environmental protection, etc. In order to design the collaborative innovation mechanism, we need to do: definite one core, play the main function of the market, attach importance to the social organization strength, build benefit sharing and benefit compensation mechanism, perfecting the administrative subject

  1. 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

  2. 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。

  3. 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

  4. 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

  5. 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.

  6. 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

  7. 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

  8. The Spatial Agglomeration Characteristics of Automotive Service Industry:A Case Study of Nanjing%城市汽车服务业空间集聚特征研究:以南京市为例

    Institute of Scientific and Technical Information of China (English)

    甄峰; 余洋; 汪侠

    2012-01-01

    随着中国城市化进程的不断深入,汽车服务业已成为城市现代服务业的重要组成部分,对城市空间影响也日益加大。以南京市为案例,对汽车服务业总体空间集聚及分行业空间集聚情况进行了分析与比较,证实了汽车服务业集聚空间的出现,不同的行业类型其空间表现是不同的。进而总结归纳出南京市汽车服务业空间布局特征,具体表现为:圈层分布特征明显,汽车销售、汽车维修养护、汽车配件、汽车租赁、汽车俱乐部五大行业在不同圈层的集聚状况也有着明显的差异;总体呈现出小集聚、大分散的格局,除了几个规模较大的集聚区,汽车服务业整体空间布局显得比较零碎;与干道交通关联紧密,大部分汽车服务业都分布于城市干道周围。%With the prosperity and development of the automotive service industry,as well as the acceleration of urbanization in China,the automotive service industry has become an important part of urban modern service industry,which on turn has an increasing impact in urban space.Taking Nanjing as a case,this paper analyzes and compares the overall spatial agglomeration as well as spatial agglomeration based on sub-industry of automotive service industry.The result indicates that different automotive service industry show different characteristics of spatial agglomeration.Then the overall spatial agglomeration characteristics of automotive service industry were concluded as follows: 1) It shows the characteristics of layer distribution.The five sub-industry,namely car sales industry,auto repair and maintenance industry,auto parts industry,car rental industry and automobile club,agglomerates differently in different layer.2) In sum,the automotive service industry indicates the feature of small gathering and large dispersion.The overall spatial layout of automotive services industry is relatively fragmented except to several larger gathering areas.3) Most

  9. 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.

  10. 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.

  11. Estudo de orientação de partículas em aglomerados gerados por modelos bidimensionais A study of particle orientation in agglomerates simulated by two-dimensional models

    Directory of Open Access Journals (Sweden)

    Vanderley de Vasconcelos

    1997-12-01

    Full Text Available Na formação de aglomerados, partículas pequenas tendem a se agregar, reduzindo a energia livre total do sistema. Mesmo quando as partículas primárias têm forma esférica e tamanhos uniformes, dependendo do tipo do processamento e das forças envolvidas, os aglomerados podem apresentar orientações preferenciais de partículas. Este trabalho utiliza técnica de processamento digital de imagens para a obtenção das distribuições de orientação de partículas em aglomerados bidimensionais simulados. As simulações foram realizadas em um ambiente de computação gráfica com recursos de modelagem de sólidos. A escolha de modelos bidimensionais para representar casos tridimensionais é um artifício muito empregado para reduzir os altos tempos de processamento computacional envolvidos no estudo de processos complexos.Apesar de simples, em príncipio, muitas conclusões importante podem ser extraídas dos modelos bidimensionais e muitos de seus resultados aplicados diretamente aos casos reais.In the formation of agglomerates, small particles tend to aggregate in order to reduce the total free energy of the system. Even when the individual particles can be treated as spheres of uniform size, depending on the process and involved forces the agglomerates can show some kind of particle orientation. This paper uses digital image processing techniques for obtaining particle orientation distribution of two-dimensional simulated agglomerates. These simulations were carried out using a computer graphics environment with solid modeling extension. The use of two-dimensional models instead of three-dimensional ones is an alternative to reduce the long computacional times involved in the analysis of complex real systems. Despite being simple, in principle, very important information can be obtained from two-dimensional systems and directly applied to real three-dimensional cases.

  12. 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.

  13. 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。

  14. 低成本、出口、空间集聚与城市成长——以沿海开放城市为例%Lowcost, Export, Spatial Agglomeration and Urban Growth

    Institute of Scientific and Technical Information of China (English)

    张超

    2012-01-01

    We set up a model of spatial agglomeration based on the optimal decision of producer. Theoretic model reveals that the low cost of wages and transportation is an important driving force of export trade. Export increase can promote the spa- tial agglomeration of export enterprises, and it will make scale effects. This further results in the price decrease of final export products, and export increase, and spatial agglomeration strengthened by itself. In the end this will bring about the sustained growth of urban economy and total population. We also analyze the relationships among the extent of low-wage, the growth of to- tal exports value and the growth of urban scale based on Granger causality tests and dynamic panel data model in some cities in coastal areas, such as Shenzhen, Zhuhai, Shantou, Dongwan and Suzhou. The results of empirical research support the conclu sions of the theoretic model.%基于生产者最优决策的空间集聚模型的分析表明,低工资成本和低运输成本是出口贸易的重要成因。同时,出口增长又能促进出口企业的空间集聚并产生规模效应,反过来进一步使出口产品价格下降、出口规模扩大和空间集聚产生自我强化,最终带动城市经济和人口规模的持续扩张。本文通过对开放型经济发展较好的深圳、珠海、汕头、东莞和苏州等沿海开放城市的低工资水平、出口规模增长和城市规模扩张之间的Granger因果检验和动态面板分析,结果支持了理论模型的分析结论。

  15. 集聚效应、配置效率与区域经济增长--主体功能区建设的理论探索%On the Agglomeration Effect, Allocation Efficiency and Regional Economic Growth

    Institute of Scientific and Technical Information of China (English)

    郝大江; 黎映宸

    2014-01-01

    Based on the analysis of economic space essential attribute, elements mobility will be flowed into the increasing returns to scale and incomplete competitive research framework, the regional and non-regional division of factor endowment can effectively reveal the problem of regional economic development. The space flow of non-regional elements formed the agglomeration process of economic activities, and the matching of regional factors and non-regional elements in the production process determines the nature, characteristics and internal economic ties of economic agglomeration and its external effects. Using fixed effect panel data as well as the system generalized moment estimation method, the author conducted empirical test on dynamic relationship between the allocation efficiency, economic agglomeration and regional economic growth in our country, the result also shows that the three further contact each other, restrict each other, and provide the new way of thinking on the space planning layout for main functional area construction in our country.%基于经济空间本质属性的分析,并将要素流动纳入规模报酬递增和非完全竞争研究框架,要素禀赋的区域性和非区域性划分可以有效揭示区域经济发展的集聚问题。非区域性要素的空间流动形成了经济活动的集聚过程,而区域性要素与非区域性要素在生产过程的相互匹配则决定了经济集聚及其外部效应的性质、特征及其内在经济联系。借助固定效应面板数据以及系统广义矩估计方法对我国配置效率、经济集聚与区域经济增长之间动态关系进行的经验检验,其结果也进一步表明了三者之间相互联系、彼此制约,为我国主体功能区建设提供了空间规划布局的新思路。

  16. 中国大菱鲆养殖业集聚演变特征及成因分析%An Analysis on the Evolution of Industrial Agglomeration of Turbot Farming Industry in China

    Institute of Scientific and Technical Information of China (English)

    侯熙格; 杨正勇; 李佳莹

    2016-01-01

    Based on the survey of turbot farming industry in China, Arc GIS10.0 was used in describing the industrial diffusion path by image depiction and the industrial concentration degree and industry agglomeration index were used to estimate the industry agglomeration level of turbot farming industry during 2009~2013 and to illustrate the causes and influencing factors of industrial diffusion and agglomeration. The results showed that Chinese turbot farming industry had mainly been concentrated in Liaoning and Shandong. The degree of its industrial agglomeration was relatively higher but there was a downward trend. The development of industrial diffusion and aggregation was mainly affected by such factors as natural resources, knowledge, technological innovation, economic policies and market demand. Both the diffusion and aggregation could promote the healthy development of turbot farming industry in China. There were also some problems with the development of turbot farming industry, which included to be lack of resources, low degree of industrialization, extensive management, misleading of industrial policy and so on. To solve these problems, it was suggested that stakeholders should protect and make full cyclic use of existing resources and promote its sustainable development by way of aquaculture technology innovation, farming cost reduction and improvement of market extension performance.%本文基于中国大菱鲆养殖业的调研,运用ArcGIS 10.0对产业扩散路径进行图像化描述,并运用行业集中度和产业空间集聚指数测度了中国大菱鲆养殖业2009~2013年间的产业集聚水平及变化,揭示了产业扩散和集聚的成因及影响因素。研究发现,中国大菱鲆养殖业主要集中在辽宁和山东两省,产业集聚程度较高,但呈下降趋势。产业扩散和聚集的形成受资源禀赋、知识及技术创新、经济效益和市场需求及产业政策等因素的影响,扩散与聚集均促进了

  17. Research on the Livability Assessment for the City Agglomeration in Central Plains Economic Zone%中原经济区主体城市群生态宜居评价与构建策略

    Institute of Scientific and Technical Information of China (English)

    于长立

    2012-01-01

    In accordance with the development of the node cities from the main urban agglomeration in Central Plains Economic Zone and the principle of cluster analysis, this paper selected 27 factors from the natural ecology and humanities ecology, built the ecological livability evaluation system by using cluster analysis, correlation coefficient method, non - correlational method and by obtaining experts' advice. With the use of entropy theory and matter - element analysis theory, this paper contacted fuzzy set with euclidean approach degree, established entropy weight fuzzy element model and gave full analysis and evaluation to the ecological livability of the main urban agglomeration in Central Plains Economic Zone. The results showed that the overall level of the ecological livability of the main urban agglomeration in Central Plains Economic Zone is moderate preference and there is much room for improvement. The ecological livability of the node cities showed uneven development among these cities, Zhengzhou is the best, Jiyuan, Xinxiang, Luohe, Xuchang followed, while Jiaozuo and Luoyang, Kaifeng, Pingdingshan are left behind. This paper also proposed countermeasures and suggestions to further strengthen the ecological livability of the main urban agglomeration in Central Plains Economic Zone.%根据中原经济区主体城市群节点城市的发展状况,按照聚类分析原理,运用聚类分析法、相关系数法、极大不相关法和征询专家意见法,选取自然生态相与人文生态相中的27个因子,构建生态宜居评价体系。引用熵值理论,采用物元分析法,联系模糊集与欧氏贴近度,建立熵权模糊物元评价模型,对中原经济区主体城市群生态宜居进行分析评价。结果显示:中原经济区主体城市群生态宜居整体水平为中等偏好,提升空间很大;群域内各节点城市发展不均衡,生态宜居水平差别较大,其中,郑州最好,济源、新乡、漯

  18. 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)

  19. 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)

  20. 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。

  1. 浅析“中原城市群”低碳城市的构建策略%The Analysis of the Construction Strategies of Low-carbon City of the"City Agglomeration in Henan Province"

    Institute of Scientific and Technical Information of China (English)

    杨若谦

    2015-01-01

    To confront with the global climate change, the concept of low carbon economic and low carbon city become more and more popular. The key point of the low carbon economy is to reduce carbon dioxide emission and energy consumption, and its mode of development is the world economic development trend in the future. Low-carbon city is not only the carrier of low-carbon economy, but also the implementation of low-carbon path to economic development. This essay introduces some methods to construct a low-carbon city such as new ways of energy technology, cleaning technology application. Treating the city agglomeration in Henan province as the research object, analyzes the feasibility to building low-carbon city, finally gives some suggestions regarding the strategies of the establishment of low-carbon cities of city agglomeration in Henan province.%为了应对全球气候的变化,低碳经济和低碳城市的概念应运而生。低碳经济的核心是降低能源消耗、减少二氧化碳排放,其发展模式是世界经济的发展趋势。低碳城市是低碳经济的载体、更是低碳经济发展的实施路径。本文简单介绍了低碳城市的构建途径:新能源技术应用、清洁技术应用等。并以中原城市群为研究对象,分析了中原城市群构建低碳城市的可行性,最后提出了关于构建低碳城市群的几点建议。

  2. 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。

  3. 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

  4. 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

  5. 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

  6. Effect of Rinse pH on the Agglomeration Degree and Electrochemical Performance of Nano-Scale β-Ni(OH)2%洗涤时pH值对纳米级β-Ni(OH)2的团聚程度和电化学性能的影响(英文)

    Institute of Scientific and Technical Information of China (English)

    赵力; 张翠芬; 周德瑞

    2002-01-01

    Nano-scale nickel hydroxide was prepared by precipitate transformation method in the paper. Effect of rinse pH on the agglomeration degree and electrochemical performance of nano-scale Ni (OH)2 was investigated. The measurement results of XRD and TEM indicate that the prepared nano-scale Ni (OH)2 is β (II)-phase, the grain size is in the rang of 10 ~ 50nm, and rinse pH exerts a great influence on the agglomeration degree of nano-scale Ni(OH) 2.The agglomeration of material becomes very obvious when rinse pH = 11, and the density of nano-scale Ni(OH)2 is enhanced obviously. Cyclic voltammetry(CV) and simulate cells experiment show that nano-scale Ni(OH)2 with suitable agglomeration degree have better electrochemical CV performance than those with ideal disperse Ni (OH)2and micron Ni(OH)2, and its proton diffusion coefficient is also the highest. It can elevate the discharge potential platform and prolongs discharge time, so the utilization ratio of Ni (OH)2 is raised.``

  7. Agglomeration of logistics industry and regional economic growth in China:Spatial econometric analysis on provincial panel data%物流产业集聚对区域经济增长影响研究--基于省际数据的空间计量分析

    Institute of Scientific and Technical Information of China (English)

    李剑; 姜宝

    2016-01-01

    Agglomeration of logistics industry makes great contributions to regional economic development, and the impact has been too big to be ignored. The present study employs the spatial econometric model to process the original data from 2004 to 2013 of 31 provinces to find out how agglomeration of logistics industry affects regional economic growth. From the overall level of regional economy, the agglomeration can effectively promote the regional economic growth and improve its efficiency. From the analysis of industry economy, the agglomeration of logistics industry makes the greatest contribution to the third industry but exerts no significant influence on the first industry. From the view of foreign trade, the logistics industry cluster only has a significant positive impact on regional import trade, but the spatial effect of logistics industry agglomeration could suppress import and export trade in the surrounding area.%选取2004—2013年中国内地31个省际数据为样本,运用空间计量模型实证分析物流产业集聚对区域经济增长的影响。研究发现,整体来看,物流产业集聚能够有效地促进区域经济增长速度和区域经济增长效率的提高;从产业经济层面分析,发现物流产业集聚对第三产业的贡献度最大,对第一产业的影响不显著;从对外贸易角度来看,物流产业集聚仅对当地进口贸易有显著正影响,但其集聚的空间溢出效应却是负的。

  8. 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.

  9. 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

  10. 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

  11. Study on Diffusion and Risk of the Regional Industry Brand Effect Based on Industrial Agglomeration%基于产业集聚的区域产业品牌效应扩散和风险研究

    Institute of Scientific and Technical Information of China (English)

    祝佳; 唐松

    2016-01-01

    Currently, the diffusion of regional industry brand effect has meant significantly to industrial competitiveness of coun-tries and areas. This paper builds a model with both intermediate goods market and consumer goods market to describe the regional in-dustry brand effect. Based on it, this paper analyzes the diffusion and risk of the regional industry brand effect from the perspective of industrial agglomeration. The study shows that there is a benign interactive relationship between the diffusion of regional industry brand effect in industrial market and consumer market, which can promote the industrial agglomeration and industrial upgrading. Without the full diffusion, bad risk for the regional developments can be generated so that it will do harm to industrial agglomeration and industrial upgrading. Therefore, government should take actions to enhance government and companies’ input on regional industry brand and government’ s supervision on it. Through these means, the regional industry brand effect can be diffused on industrial market and con-sumer market so that it can promote the transformation and upgrading of industrial structure.%当前区域产业品牌效应的扩散已成为影响国家和地区产业竞争力的重要因素。本文构建了一个同时存在中间品市场和消费品市场的理论模型刻画区域产业品牌效应,在此基础上从产业集聚角度对区域产业品牌效应的扩散及其风险进行分析。研究结果表明:产业市场和消费品市场上区域产业品牌效应的扩散存在良性互动关系,对产业集聚和产业升级具有促进作用;反之,如果区域产业品牌不能充分扩散,会形成不利于地区发展的风险,不利于产业集聚和产业升级。因此,政府应采取各种政策措施以加强政府和企业对区域产业品牌的投入,同时加强对区域产业品牌的监督管理,实现区域产业品牌在产业市场和消费品市场上的扩散

  12. 基于集聚经济的海上旅游规划研究--以秦皇岛为例%Marine Tourism Planning Research Based on Agglomeration Economies-An Analysis of Qinhuangdao

    Institute of Scientific and Technical Information of China (English)

    韩元军; 杨德进

    2013-01-01

    中国休闲度假时代的来临带动着国内海上休闲旅游蓬勃发展,以秦皇岛市海上旅游规划为例,尝试性提出旅游目的地集聚经济论,并且认为秦皇岛核心旅游目的地聚集经济形成与否决定了海上旅游规划的成败,进而通过静态和动态博弈分析得出秦皇岛海上旅游发展战略应采取与周边滨海城市合作的互助模式,海上旅游空间规划则需要从旅游产品设计、旅游线路组织、海上配套设施建设、海上旅游品牌营销等方面打造出秦皇岛独具魅力的海上旅游体系。%The advent of China ’ s leisure era promotes the development of domestic marine leisure tourism .In this paper, taking Qinhuangdao city marine tourism planning as an example , the author attempts to put forward a theory on tourism destination agglomeration economy .And the author thinks that the formation or not of Qinhuangdao core tourism destination agglomeration economies determines the success or failure of the marine tourism planning .And then, through the static and dynamic game analysis , the author gets a decision that the Qinhuangdao sea tourism development strategy should adopt the mutual aid mode of cooperating with surrounding coastal city .To build Qin-huangdao ’ s unique charming sea travel system , tourism place planning at sea needs to be implemented from the as-pects of tourism product design , organization of tour routes , offshore facilities construction and marine tourism brand marketing.

  13. 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

  14. 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.

  15. Investigation and Analysis on Leisure Sporting Patterns for the Middle Class in Chang -Zhu -Tan Urban Agglomeration%长株潭中产阶层体育休闲现状的调查与分析

    Institute of Scientific and Technical Information of China (English)

    陆海英

    2011-01-01

    The middle class is an important force for the stability of the modern society. The leisure sporting patterns for the middle class in Chang - Zhu - Tan urban agglomeration are characterized by strong sense of physicalexercise, the diversity of leisure patterns and events choosing, the high proportion of choosing the sports charge be- tween athletics cognition and sport activity. Therefore, the mass organizations, products, environment, ideology andatmosphere of the various leisure patterns for the middle class should be energetically organized, cuhivated and constructed so as to meet the sports consumption demand for the middle class and the general public.%中产阶层是现代社会稳定的一支重要力量。长株潭城市群中产阶层的体育休闲方式具有体育锻炼意识强,休闲方式及体育活动项目的选择多样化,体育休闲选择收费场馆的比例高,但体育认知与实践有差距等特征或局限。应该大力组织、培育和营造中产阶层各种体育休闲的社团、产品、环境、意识和氛围,以迎合中产阶层及广大市民的体育消费需求。

  16. 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

  17. “准文化产业”如何实现集聚优势--以茶文化产业为个案分析%How can the Quasi-culture Industry realize the superiority of agglomeration?--A Case Study of Tea Culture Industry

    Institute of Scientific and Technical Information of China (English)

    林玮

    2013-01-01

    Quasi-culture industry is the products and services with culture quality which can be consumed but out of the national culture industry policy system. A quasi-culture industry relies on one certain manufacture. It is the patterns compound of second industry and third industry. Taking the tea culture industry as a case, the agglomeration of quasi-culture industry can be divided into procreative agglomeration and marketable agglomeration. The culture qualities of procreative agglomeration come from the natural endowments or human history, and the culture qualities of marketable agglomeration stem from originality. The agglomeration of quasi-culture industry has some problems such as low barrier of entry printing field, serious free-rider, less product differentiation, and insufficient reference to the core culture industry. This situation should be improved by weakening the dependence on the certain manufacture and highlighting the independence of quasi-culture industry. The ways to realize the superiority of quasi-culture industry agglomeration include: (1) exploiting the culture resources of quasi-culture industry in the condition of valuing the practicability of it; (2) drawing support from agglomeration of the certain manufacture, and realizing the zone industrialization;(3) taking culture and originality as the core element in the development of quasi-culture industry. The quasi-culture industry should be treated as the independent type of operation, and regulated and controlled referring to the national culture industry policies, which can realize the cross-sectoral operation of culture industry.%  “准文化产业”是指在现行国家文化产业政策体系之外存在的具有可供消费的文化特质的产品和服务,它依托特定的制造业而存在,是第二产业和第三产业的复合产业形态。以茶文化产业为例,准文化产业集聚可分为产地集聚和市场集聚。前者的文化属性主要来源于自然禀赋

  18. 中国制造业集聚对创新效率影响的实证研究--基于动态面板数据的GMM 估计%An Empirical Study of the Impact of Chinese Manufacturing Industry Agglomeration on Innovation Efficiency:Based on GMM Test of Dynamic Panel Data

    Institute of Scientific and Technical Information of China (English)

    韩庆潇; 查华超; 杨晨

    2015-01-01

    Firstly, this paper measures the level of innovation efficiency by Malmquist index.Then, based on 2003-2012 dynamic panel data, this paper tests the impact of industry agglomeration on innovation efficiency in all and different types of factor intensity manufacturing industries.The conclusion is as follows:from the perspective of the whole manufactur-ing industries, industry agglomeration can effectively increase innovation efficiency, wheras in the manufacturing industries classified according to the factor intensity, only technology-intensive industry agglomeration can effectively increase innovation efficiency, and the impact of agglomeration is not significant in labor-intensive and capital-intensive industries.%本文运用曼奎斯特指数对我国制造业子行业的创新效率进行测度,基于2003-2012年的动态面板数据实证检验了整个制造业及按不同要素密集度划分的制造业中产业集聚对创新效率的影响。研究结果显示,从制造业总体来看,产业集聚水平的增加可有效促进创新效率的提高,按要素密集度划分的制造业中只有技术密集型制造业的集聚能有效促进创新效率的提高,劳动密集型和资本密集型制造业的促进作用并不显著。

  19. 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.

  20. Study on Agglomeration Economies and Development Countermeasures of College Town——With the Sample of Nanchang College Towns%大学城集聚经济效应及其发展对策研究——以南昌市大学城为例

    Institute of Scientific and Technical Information of China (English)

    梅丽珍

    2012-01-01

    本文根据大学城的定义及集聚经济效应的相关理论,在探讨大学城集聚经济效应及我国大学城的建设历史的基础上,分析了南昌市大学城的集聚经济效应现状,并提出了加强教育资源的共享、专业与产业的融合、高校与企业合作培养人才等促进其发展的对策。%According to the definition of College Town and the theories of agglomeration economies,the present situations of Nanchang College Towns' agglomeration economies are analyzed based on discussing the agglomeration economies of College Town and the development histories of our College Towns.Some countermeasures about promoting Nanchang College Towns developing are put forward,such as facilitating the sharing of the teaching resources,the combination of the specialties and industries and the cooperation of the colleges and the enterprises.

  1. A Study on the Interaction Mechanism of Small and Medium-sized Enterprises’ Agglomeration of Innovation and Cluster Network%中小企业集聚创新与集群网络互动机理研究

    Institute of Scientific and Technical Information of China (English)

    李新安

    2015-01-01

    中小企业集聚及其相互间的知识流动是推动集群创新和发展的重要力量。传统农区的中小企业集聚及其内部网络在促进集群创新方面的相互作用机制,尚需通过调查样本来研究。文章在整合社会网络理论、集群理念和创新理论的基础上,提出网络关系强度与集群的信息量度和信息效度的假设关系,并通过传统农区虞城钢卷尺集群的问卷调查与结构方程模型对集群的创新效率假设关系进行检验。结果发现,不同网络关系强度对集群的创新效率提升途径并不一致,传统农区的集群网络关系会通过影响集群企业获取的信息量度、信息效度、创新压力感和水平来影响集群的创新效率。基于以上研究结论,从传统农区集群发展视角,为中小企业集群更好发展和创新能力提升提出了相应的对策建议。%Small and medium-sized enterprises agglomeration and knowledge flow within it are an important force to promote cluster innovation and development. It still needs to study by the survey sample that the interaction mecha⁃nism of the agglomeration of small and medium-sized enterprises and its internal network on promoting cluster inno⁃vation in traditional agricultural area. The paper,based on the integration of social network theory,cluster concept and innovation theory, brings forward an assumption relationship between network relationship strength and cluster information quantity and quality, and makes a test on the assumption relationship of cluster innovation efficiency by applying the steel tape cluster questionnaire survey in Yucheng county of traditional agricultural area and the structural equation model. The results show that different network relationship strength is not consistent with the way to promote cluster innovation efficiency. The cluster network relationship of traditional agricultural area has an effect on cluster innovation efficiency by

  2. Service Agglomeration, Spatial Spillovera nd Quality of Economic Growth---An Empirical Analysis Based on Spatial Dubin Model%服务业集聚、空间溢出与经济增长质量--基于中国省际空间面板杜宾模型的经验研究

    Institute of Scientific and Technical Information of China (English)

    杨孟禹; 张可云

    2016-01-01

    The paper establishes Spatial Durbin Model to estimate the impact of service industry agglomeration on the quality of economic growth.The result indicates that diversified agglomeration of service industry has a positive effect on im-proving the quality of economic growth, but the role of enterprise competition and specialized agglomeration is not significant. Furthermore, a robust test finds that the agglomeration of service industry has a positive effect on not only the province itself but also the adjacent regions.Enterprise competition, in contrast, plays a negative role.Additionally, the eastern areas have the ad-vantage in terms of location.Ultimately, in view of the possible oversize of sample space, the article makes an estimate of the spatial spillover centering on the provincial capital and forming the distance belt by accumulation for every 20 or 10 kilometers. The estimate shows that the spatial spillover of service industrial agglomeration is positive with the existence of space boundary.%本文基于2000-2013年中国省际面板数据,采用空间杜宾模型研究服务业集聚及其空间溢出对经济增长质量的影响,发现多样化服务业集聚对本省份和邻近省份的经济增长质量作用为正,服务业内竞争对本省份的经济增长质量影响不显著,但对邻近省份具有负作用,专业化集聚对本省份和邻近省份的影响均不显著;稳健性分析表明以上结论稳健且东部地区在服务业集聚提升经济增长质量方面具有区位优势。针对可能存在的空间分割,以各省会为圆心、每20 km或10km 进行累加形成距离带并对空间溢出进行估算,表明服务业集聚的空间溢出存在空间边界。

  3. 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.

  4. 基于集聚优势耗散的集群企业外迁动因实证研究%The relocating motivation of cluster firms based on the perspective agglomeration advantage dissipation

    Institute of Scientific and Technical Information of China (English)

    吴波

    2012-01-01

    针对集群企业外迁现象,学术界提出了集聚优势耗散理论。基于已有研究,本文在区域层面进一步识别驱动集群企业外迁的关键要素,在企业层面揭示“能力异质性”和“规模差异性”对集群企业外迁不同的影响机制。以慈溪家电产业集群为对象的实证研究表明,在区域层面,企业不可控区域要素是影响集群企业外迁的关键动因;在企业层面,能力强的家电企业并没有表现出显著的外迁意愿,而规模大的家电企业则表现出显著的本地留守意愿。%The theory of agglomeration advantage dissipation has emerged as a key guidance for inquiring into the determinants of cluster firms' relocating motivation. Based on previous researches, the key factors in a regional level motivating the relocation of cluster firms are further identified; and at the firm level, the different influential mechanisms of capability heterogeneity and scale difference on the relocation of cluster firms revealed. Focusing on home appliances industry cluster in Cixi of Zhejiang Drovince, it is found that incontrollable regional factors are the key factors influencing cluster firms' relocation motivation ; the cluster firms with strong capability does not indicate clear relocating motivation; and the cluster firms with large scale show evident motivation to stay.

  5. Research on Technology Service Industry Spatial Agglomeration Characteristics and Influencing Factors in China%中国科技服务业集聚的空间分析及影响因素研究

    Institute of Scientific and Technical Information of China (English)

    张清正

    2015-01-01

    Using the relevant data about Chinese provinces technology services and economic development from 1995 to 2013, this paper investigated the development of Chinese technology service industry spatial agglomeration situation by visu-alization of geographic information system. On this basis, combining with the formation, evolution and the development of technology service industry in our country, it depth studied economic development, government behavior, knowledge spillo-vers, technological strength, economies of scale, transaction costs impact on the development of technology service industry, and put forward China’s technology service industry development path.%利用1995~2013年中国各省域科技服务业与经济发展有关数据,通过全局空间相关分析局部空间相关分析,基于ESDA方法考察了中国科技服务业空间集聚发展的态势;结合我国科技服务业集聚发展的形成、演化及发展过程,深入探究了中国科技服务业集聚发展的经济发展、政府行为、知识溢出、科技实力、规模经济、交易费用六大影响因素体系,进一步从横向支撑体系、纵向支撑体系、结构支撑体系提出了推进中国科技服务业发展的路径选择。

  6. Measurement and Analysis of Producer Services' Agglomeration Level in Hebei Province%河北省生产性服务业集聚水平的测度与分析

    Institute of Scientific and Technical Information of China (English)

    刘艳芳

    2014-01-01

    Producer services are“powerful tools” to build China's industrial upgrading version, and also inevitable choice for Hebei to change industrial structure c from“made in Hebei” to“service in Hebei”. This paper first introduces the current situation of pro-ducer services in Hebei province, and then based on location en-tropy index method, it has carried on measurement and analysis of producer services' agglomeration level in Hebei and its subordinate cities, showing that it has industry and regional distribution imbal-ance. Finally, it puts forward some countermeasures and sugges-tions to promote the development of producer services in Hebei province.%生产性服务业是打造中国产业升级版的“利器”,是河北省实现产业格局由“河北制造”向“河北服务”转变的必然选择。本文首先介绍了河北省生产性服务业的发展现状,然后基于区位熵指数法,对河北省七大生产性服务业及河北省各地级以上城市的生产性服务业集聚水平进行了测算与分析,发现其发展在行业和地区上分布不均衡,最后提出了促进河北省生产性服务业发展的对策建议。

  7. 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.

  8. 基于交流演化的城市群创新主体协同博弈研究%Synergy Game Analysis on Innovators of the Urban Agglomeration based on Communication Evolution

    Institute of Scientific and Technical Information of China (English)

    刘爱君; 晏敬东

    2015-01-01

    Communication among the innovators of the urban agglomeration is a sufficient condition for the synergy inten‐tion ,it would affect the synergy stability and the result of system evolution .Structures a synergy communication game model between innovators ,analyzes their communicate agent ,discusses the synergistic stability using the indirect evolu‐tion .The conclusion is that the innovation profit would be the direct synergy motivation ,the homogeneous and heterogene‐ous innovators would affect the synergy willingness ,and the main scale difference ,condition and others affect the evolution path comprehensively .At last analyzes the synergy mechanism of the innovator and puts out the corresponding policy sug‐gestion .%城市群创新主体交流沟通是其产生协同意愿的充分条件,会影响协同稳定性和系统演化结果。构建了城市群创新主体协同交流博弈模型,分析了创新主体交流动因,并用间接演化方法探讨了其协同稳定性问题,认为创新利润是直接的协同动因,同质和异质性创新主体协同会影响协同意愿,且其规模差异及条件等因素综合影响演化路径。最后对城市群创新主体协同保障机制进行了分析,并提出了相应的对策建议。

  9. 灰融聚流化床粉煤气化技术应用及节能减排措施%Use of Agglomerating Ash Fluid Bed Pulverized Coal Gasification Technology and Measures for Energy Saving and Discharge Reduction

    Institute of Scientific and Technical Information of China (English)

    毕可军

    2011-01-01

    The agglomerating ash fluid bed pulverized coal gasification technology is described, its special features, process flow and the measures taken for energy saving and discharge reduction, with results. A comparison is given of the gasifiers at atmospheric and 1. 0 Mpa pressures for the production of 1 000 m3 of gas with the UGI oxygen-enriched gasifier, and the results show that the energy consumption of the atmospheric fluid bed gasifier is slightly lower than that of the UGI oxygen-enriched gasifier, while the 1.0 Mpa pressurized one is more advantageous than the atmospheric one in terms of energy saving.%介绍了灰融聚流化床粉煤气化技术的特点、工艺流程及采取的节能减排措施和效果.对常压和加压1.0 MPa灰融聚流化床粉煤气化炉生产1 000m3煤气的能耗分别与UGI富氧气化炉进行比较,结果表明:常压灰融聚流化床粉煤气化技术的能耗略低于UGI富氧气化技术,而加压1.0 MPa灰融聚流化床粉煤气化技术比常压灰融聚流化床粉煤气化技术在节能方面更具优势.

  10. 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.

  11. 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.

  12. 灰熔聚流化床气化炉内气固两相流的数值模拟%NUMERICAL SIMULATION OF GAS-SOLID FLOW IN THEASH-AGGLOMERATING FLUIDIZED BED GASIFIER

    Institute of Scientific and Technical Information of China (English)

    范江; 武小芳; 马素霞

    2011-01-01

    Eulerian-Eulerian two-fluid model was used to simulate the gas-solid flow behaviors in certain chemical fertilizer company' s running ash-agglomerating fluidized bed gasifier . The range and proper matching relations between fluidized and spouting gas velocity were showed from the simulating results. It shows fluidized gas velocity can neither be too small, which may lead to dead districts around the gas distributor, nor too big because the designing and operating characteristics of ICC will be lost. With the increasing of spouting gas velocity, the mixing churning is enhanced under a certain fluidizing gas velocity. However, spouting gas velocity which exceeds some value results in the flow structure of slugging and is not conducive to the operating of ICC efficiently and safely.%应用欧拉双流体模型模拟了某化肥厂现运行的灰熔聚流化床煤气化炉(用ICC表示)内的气固两相流动行为,得出了所模拟ICC的合理流化气速与喷动气速的速度范围及匹配关系:流化气速不能太小,否则布风板区域会出现死区;流化气速也不能太大,否则将失去ICC的设计运行特点.当流化气速一定时,随喷动气速的增加,搅动混合增强,但过大的喷动气速会使床内的流动结构出现腾涌,不利于ICC的高效安全运行.

  13. Development Strategies and Countermeasures for Nanchang’s Participation in Urban Agglomeration of the Yangtze River Middle Reaches%南昌参与长江中游城市群建设思路及对策研究

    Institute of Scientific and Technical Information of China (English)

    郭建斌

    2013-01-01

    According to the analysis of SWOT,this paper discusses development strategies and countermeasures for Nanchang’s participation in the urban agglomeration of the Yangtze River Middle Reaches,maintaining that Nanchang needs to strengthen regional cooperation and intensify the function of the central city. Meanwhile,it highlights the advantages of Nanchang industry and good coordination of government through the detailed divi-sion of labor,the hinterland of linkage,and the way of strengthening government function. Finally it concludes Nanchang must formulate scientific development of Nanchang city planning to participate in the construction of the middle reaches of the Yangtze River city group through establishing regional industry value chain,multiple cooperation strategic alliance,emerging industry highlands and regional market system and talent cooperation platform for cities in the middle reaches of the Yangtze River.%南昌参与长江中游城市群建设既有优势又有劣势,既面临机遇也面临挑战。依据SWOT分析提出了南昌参与长江中游城市群建设的思路与对策,南昌应主动寻求区域合作,共同承担中心城市功能,通过细化分工、联动腹地,加强政府职能,凸显南昌产业的比较优势;同时科学制定发展规划,集中力量建立产业价值链多元合作战略联盟,构筑南昌新兴产业高地和区域特色市场体系,从而强有力的推进南昌参与长江中游城市群的建设。

  14. 湖南省城市群生态网络构建与优化%Developing and optimizing ecological networks in urban agglomeration of Hunan Province,China

    Institute of Scientific and Technical Information of China (English)

    尹海伟; 孔繁花; 祈毅; 王红扬; 周艳妮; 秦正茂

    2011-01-01

    On a regional scale , large habitat patches which are important regional sources of biological diversity can provide important functions in habitat protection for biodiversity conservation. However, due to rapid urbanization, large habitat patches have become increasingly fragmented, and are almost like an island surrounded by the built-up area. The connectivity among these habitat patches is gradually waning. Changes in land use around these large patches have very strong impacts and seriously threaten regional biodiversity conservation. Habitat fragmentation would lead to smaller and more isolated animal populations and the isolated populations are more vulnerable to local extinction and inbreeding depression. An Ecological network is a representation of the biotic interaction in an ecosystem while ecological network planning is a method that combines fragmented habitat patches to form landscapes with spatial integrity and habitat networks. This method can help raise the quality of natural ecosystems and protect biodiversity. Thus, the establishment of ecological networks and the restoration of the links between isolated habitat patches would be quite beneficial to ecosystem services. In this paper, based on the theory and principles of Landscape Ecology and Conservation Biology, taking urban agglomeration in Hunan Province as the example, the potential ecological corridors were quantitatively simulated using the Least-Cost Path and Scenario Analysis Methods with the help of Remote Sensing and GIS technology. The strength of the interaction between green patches was then evaluated quantitatively based on the Gravity model. The impacts of' the result of potential ecological networks by the cost surface were also analyzed. Finally, suggestions on how to optimize the ecological network were accordingly put forward. This paper tried to answer the following three questions: (1) what are the potential ecological corridors of urban agglomeration in Hunan Provence and

  15. 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

  16. Vectorized image segmentation via trixel agglomeration

    Science.gov (United States)

    Prasad, Lakshman; Skourikhine, Alexei N.

    2006-10-24

    A computer implemented method transforms an image comprised of pixels into a vectorized image specified by a plurality of polygons that can be subsequently used to aid in image processing and understanding. The pixelated image is processed to extract edge pixels that separate different colors and a constrained Delaunay triangulation of the edge pixels forms a plurality of triangles having edges that cover the pixelated image. A color for each one of the plurality of triangles is determined from the color pixels within each triangle. A filter is formed with a set of grouping rules related to features of the pixelated image and applied to the plurality of triangle edges to merge adjacent triangles consistent with the filter into polygons having a plurality of vertices. The pixelated image may be then reformed into an array of the polygons, that can be represented collectively and efficiently by standard vector image.

  17. 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

  18. 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

  19. Breakage of Agglomerates: Attrition, Abrasion and Compression

    OpenAIRE

    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 and inhomogeneous which makes mechanical characterization difficult, so the strength is difficult to measure. The objective of this thesis is to develop and validate new particle breakage testers fro...

  20. 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 .