Application framework of urban morphology in planning practice : a case study of Beijing

Although it is generally recognized that a connection exists between urban form and urban planning practice, there is still a long way to go before the theories, concepts and methods of urban morphology can be widely applied to daily planning practice. Firstly, the paper makes a theoretical thinking. It is concluded that: 1. Urban form and urban planning practice are dynamic processes of space-time interaction; 2. Urban morphology research and urban planning are the relationship between knowledge and practice;3. Urban morphology research needs to be combined with urban planning business. Secondly, the paper puts forward an application framework of urban morphology in planning practice, including four aspects: knowledge base, analytical dimension, technical support and planning practice. The framework focuses on the space geometry, industrial economy, traffic organization, residential space, urban design, land use and policies in the research of urban morphology under different scales, more closely related to the main focuses in the discipline and practice of urban planning. Thirdly, this paper describes the application of the framework in Beijing planning practice in recent years and illustrates it plays a role and value in the actual planning business

Weak-Light Image Enhancement Method Based on Adaptive Local Gamma Transform and Color Compensation

This article proposes a correction method for image enhancement models based on an adaptive local gamma transformation and color compensation inspired by the illumination reflection model. It is demonstrated that the proposed method adaptively reduces the influence of uneven illumination to avoid overenhancement and improves the visual effect of low-light images

México: informe de la coyuntura económica: primer trimestre de 1999

Incluye Bibliografí

Mesenchymal stem cells as carriers and amplifiers in CRAd delivery to tumors

<p>Abstract</p> <p>Background</p> <p>Mesenchymal stem cells (MSCs) have been considered to be the attractive vehicles for delivering therapeutic agents toward various tumor diseases. This study was to explore the distribution pattern, kinetic delivery of adenovirus, and therapeutic efficacy of the MSC loading of E1A mutant conditionally replicative adenovirus Adv-Stat3(-) which selectively replicated and expressed high levels of anti-sense Stat3 complementary DNA in breast cancer and melanoma cells.</p> <p>Methods</p> <p>We assessed the release ability of conditionally replicative adenovirus (CRAd) from MSC using crystal violet staining, TCID₅₀assay, and quantitative PCR. In vitro killing competence of MSCs carrying Adv-Stat3(-) toward breast cancer and melanoma was performed using co-culture system of transwell plates. We examined tumor tropism of MSC by Prussian blue staining and immunofluorescence. In vivo killing competence of MSCs carrying Adv-Stat3(-) toward breast tumor was analyzed by comparison of tumor volumes and survival periods.</p> <p>Results</p> <p>Adv-Stat3(-) amplified in MSCs and were released 4 days after infection. MSCs carrying Adv-Stat3(-) caused viral amplification, depletion of Stat3 and its downstream proteins, and led to significant apoptosis in breast cancer and melanoma cell lines. In vivo experiments confirmed the preferential localization of MSCs in the tumor periphery 24 hours after tail vein injection, and this localization was mainly detected in the tumor parenchyma after 72 hours. Intravenous injection of MSCs carrying Adv-Stat3(-) suppressed the Stat3 pathway, down-regulated Ki67 expression, and recruited CD11b-positive cells in the local tumor, inhibiting tumor growth and increasing the survival of tumor-bearing mice.</p> <p>Conclusions</p> <p>These results indicate that MSCs migrate to the tumor site in a time-dependent manner and could be an effective platform for the targeted delivery of CRAd and the amplification of tumor killing effects.</p

A practical approach to produce Mg-Al spinel based on the modeling of phase equilibria for NH4Cl-MgCl2-AlCl3-H2O system

Based on chemical modeling of phase equilibria for the NH4Cl-MgCl2-AlCl3-H2O system, a practical approach to produce Mg-Al spinel (MgAl2O4) (widely used as refractory brick, supports in catalysts, and inert material for oxygen carriers) is proposed and proven feasible. This novel process includes coprecipitation of Mg4Al2(OH)14 center dot 3H2O from the NH3-MgCl2-AlCl3-H2O system; calcination of Mg4Al2(OH)14 center dot 3H2O to obtain Mg-Al spinel and recovery of NH4Cl from NH4Cl-rich solutions by feeding MgCl2-AlCl3. A MSMPR reactor was applied to investigate the effect of temperature, feed concentration, and NH4Cl addition on coprecipitation of precursor Mg4Al2(OH)14 center dot 3H2O from MgCl2-AlCl3 solutions with Mg/Al ratio = 2 through gradual addition of NH4OH. The phase equilibria of the NH4Cl-MgCl2-AlCl3-H2O system were determined over the temperature range 283.2 to 363.2 K using dynamic method. The experimental solubilities were regressed to obtain new Bromley-Zemaitis model parameters. These newly obtained parameters were verified by predicting the quaternary system. A chemical model for the NH4Cl-MgCl2-AlCl3-H2O system has been established with the OLI platform. All the results generated from this study will provide the theoretical basis for Mg-Al spinel production. The high quality Mg-Al spinel was prepared by calcination of precursor from 773.2 to 1273.2 K, and the NH4Cl was successfully recovered through the common ion effect of MgCl2-AlCl3 addition. (c) 2012 American Institute of Chemical Engineers AIChE J, 59: 18551867, 201

Solubility of AlCl3 center dot 6H(2)O in the Fe(II) plus Mg plus Ca plus K + Cl + H2O System and Its Salting-Out Crystallization with FeCl2

Phase equilibria determination for the Al + Fe(II) + Mg + Ca + K + Cl + H2O system showed that FeCl2 is effective to promote the salting-out crystallization of AlCl3 center dot 6H(2)O. A novel process to recover AlCl3-6H(2)O from fly ash by salting-out crystallization with FeCl2 is proposed and proven feasible. This novel process includes leaching of fly ash by hydrochloric acid, reduction of Fe3+ to Fe2+, salting-out crystallization of AlCl3 center dot 6H(2)O with FeCl2, and filtering followed by washing. The solubility of AlCl3 center dot 6H(2)O in the Fe(II) + Mg + Ca + K + Cl + H2O system was determined over the entire practical concentration range and from 283.2 to 363.2 K using a dynamic method. The experimental solubilities were regressed to obtain new mixed solvent electrolyte (MSE) model parameters. These new parameters were capable of accurately representing the experimental data of the system from 283.2 to 343.2 K. The phase diagram of the ternary AlCl3-FeCl2-H2O system at 298.2 and 333.2 K was successfully constructed with the aid of the new MSE model parameters Based on the phase diagram, a promising route to recover AlCl3 center dot 6H(2)O by salting-out crystallization with FeCl2 was generated and verified to be feasible in laboratory experiments. All the results generated from this study will provide fundamental data for industrial applications aiming at the recovery of alumina from fly ash resources

Solubility and K-SP of Mg4Al2(OH)(14)center dot 3H(2)O at the various ionic strengths

Mg4Al2(OH)(14)center dot 3H(2)O was prepared from co-precipitation of magnesium and aluminum in mixed MgCl2-AlCl3 solutions. The solid prepared in the condition of initial C-Al=0.0625 M, Mg/Al = 2, at 323.2 K was confirmed to be Mg4Al2(OH)(14)center dot 3H(2)O by XRD, chemical analysis, and TGA. Since it was very difficult to obtain the supemate through filtration in order to determine the solubility of Mg4Al2(OH)(14)center dot 3H(2)O in pure water, the solubility of Mg-4-Al-2(OH)(14)center dot 3H(2)O in 0.1-2.0 M NaCl solutions was measured in the temperature range of 298.2-333.2 IC. The log Ksp for the reaction Mg4Al2(OH)(14)center dot 3H(2)O(4) double left right arrow 4Mg(2+) + 2A1(OH)(4)(-) + 6OH(-) + 3H(2)O at 298.2 K was determined to be -49.09. The activity coefficients of ions and activity of water in the Mg4Al2(OH)(14)center dot 3H(2)O-saturated NaCI solutions were calculated by the Bromley-Zemaitis and Meissner equations with the help of the OLI software. The solubility product increases linearly with the inverse of temperature suggesting a constant enthalpy of reaction at 298.2-333.2 K. On the basis of solubility product regression, the free energy of formation, Delta G(f)(0).(298.15K)(Mg4Al2(OH)(14)center dot 3H(2)O), was obtained with a value of -6365.50 kJ center dot mol(-1). The enthalpy and entropy of reaction, Delta H-r(0) and Delta S-r(0), were also calculated from linear regression to be -145.57 kJ center dot mol(-1) and -1429 J center dot mol(-1), respectively. Using values for log K-SP, Delta H-r(0), Delta S-r(0) and partial molal quantities for the constituent ions, the enthalpy of formation Delta H-f(0).298.15K and the entropy of formation Delta S-f.98.15K were obtained and were -7145.05 kJ.mol(-1) and 1241 J.mol(-1).K-1, respectively. The heat capacity of Mg4Al2(OH)(14)center dot 3H(2)O was determined to be -485 J.mol(-1).K-1 assuming Delta C-p,r(0)=0. In addition, the precipitation diagrams of Al(OH)(3). Mg4Al2(OH)(14)center dot 3H(2)O, and Mg(OH)(2) were successfully constructed with the aid of the newly obtained K-SP of Mg4Al2(OH)(14)center dot 3H(2)O. These show that Mg4Al2(OH)(14)center dot 3H(2)O can only be obtained from mixed MgCl2-AlCl3 solutions (Mg/Al ratio =2) with magnesium concentration <1 M and pH above 6. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved

Ind. Eng. Chem. Res.

A process of extracting magnesium from serpentine to produce Mg compounds by using recyclable NH3 was proposed. This process includes calcination of serpentine; dissolution of magnesium by NH4Cl leaching to obtain NH3 and MgCl2-rich solution, and precipitation of Mg(OH)(2) from refined MgCl2-rich solution by feeding NH3. The effects of various factors, such as roasting temperature and time, particle size, concentration of NH4Cl solution, solid-to-liquid ratio, and leaching temperature, on the dissolution kinetics of magnesium of the calcined serpentine were comprehensively investigated. It is found that the extraction rate of magnesium was enhanced by the removal of NH3 generated from the reaction system. Thus, the obtained optimum conditions for magnesium extraction from serpentine are a roasting temperature of 700 degrees C, a roasting time of 1 h, a particle size fraction of -0.20 + 0.10 mm, an initial ammonium chloride concentration of 4.0 M, a solid-to-liquid ratio of 20/500 g/mL, and a reaction temperature of 104 degrees C. With the removal of NH3 in batch leaching study, the maximum recovery of magnesium reached 83.87%, and the concentration of magnesium was similar to 0.63 mol.L-1, satisfying the requirement of Mg(OH)(2) precipitation. Finally, the reaction kinetics of the system was successfully modeled by an empirical diffusion-like equation. The apparent activity energy was obtained to be 23.56 +/- 1.06 kJ.mol(-1). The results from this study provide the fundamentals for magnesium extraction from serpentine by NH4Cl leaching.A process of extracting magnesium from serpentine to produce Mg compounds by using recyclable NH3 was proposed. This process includes calcination of serpentine; dissolution of magnesium by NH4Cl leaching to obtain NH3 and MgCl2-rich solution, and precipitation of Mg(OH)(2) from refined MgCl2-rich solution by feeding NH3. The effects of various factors, such as roasting temperature and time, particle size, concentration of NH4Cl solution, solid-to-liquid ratio, and leaching temperature, on the dissolution kinetics of magnesium of the calcined serpentine were comprehensively investigated. It is found that the extraction rate of magnesium was enhanced by the removal of NH3 generated from the reaction system. Thus, the obtained optimum conditions for magnesium extraction from serpentine are a roasting temperature of 700 degrees C, a roasting time of 1 h, a particle size fraction of -0.20 + 0.10 mm, an initial ammonium chloride concentration of 4.0 M, a solid-to-liquid ratio of 20/500 g/mL, and a reaction temperature of 104 degrees C. With the removal of NH3 in batch leaching study, the maximum recovery of magnesium reached 83.87%, and the concentration of magnesium was similar to 0.63 mol.L-1, satisfying the requirement of Mg(OH)(2) precipitation. Finally, the reaction kinetics of the system was successfully modeled by an empirical diffusion-like equation. The apparent activity energy was obtained to be 23.56 +/- 1.06 kJ.mol(-1). The results from this study provide the fundamentals for magnesium extraction from serpentine by NH4Cl leaching

Determination and Chemical Modeling of Phase Equilibria for the Glycine-KCl-NaCl-H2O System and Its Application To Produce Crystals with Anticaking Characteristics

The phase equilibria of the glycine-KCl-NaCl-H2O system were determined in the concentrations up to 3.33 mol.kg(-1) over the temperature range from 283.2 to 363.2 K using a dynamic method. A rigorous chemical model for the glycine-KCl-NaCl-H2O system was established by the Pitzer model with the help of an OLI platform. With the equilibrium constants of dissociation reactions obtained by standard-state thermodynamic data, the new Pitzer model parameters were harvested by regressing solubility of the system. These newly obtained parameters were used to accurately predict the multiple saturated points at the temperature range from 283.2 to 363.2 K. The phase behavior of the ternary glycine-KCl-H2O and glycine-NaCl-H2O system at 298.2 and 343.2 K were successfully visualized with lucidity on an equilateral triangle. To investigate the effect of glycine on the morphology of KCl, the KCl crystals were produced from glycine solution with different concentration (17-25% w/v) by evaporation at ambient temperature. The glycine (25% w/v)-modified KCl crystal changed its morphology from native cubic to hexagonal prism form with the angle of repose from 32 degrees to 23.8-25.8 degrees, indicating a good flowability and anticaking characteristics. Finally, KCl supersaturation variation with evaporation time was simulated with aid of the chemical model established in present study to elucidate the influence of glycine concentration on the anticaking characteristics of KCl crystal. All the results generated from this study will provide the fundamentals for industrial application to produce crystals with anticaking characteristics

Determination and Chemical Modeling of Phase Equilibria for the Glycine–KCl–NaCl–H₂O System and Its Application To Produce Crystals with Anticaking Characteristics

The phase equilibria of the glycine–KCl–NaCl–H₂O system were determined in the concentrations up to 3.33 mol·kg^–1 over the temperature range from 283.2 to 363.2 K using a dynamic method. A rigorous chemical model for the glycine–KCl–NaCl–H₂O system was established by the Pitzer model with the help of an OLI platform. With the equilibrium constants of dissociation reactions obtained by standard-state thermodynamic data, the new Pitzer model parameters were harvested by regressing solubility of the system. These newly obtained parameters were used to accurately predict the multiple saturated points at the temperature range from 283.2 to 363.2 K. The phase behavior of the ternary glycine–KCl–H₂O and glycine–NaCl–H₂O system at 298.2 and 343.2 K were successfully visualized with lucidity on an equilateral triangle. To investigate the effect of glycine on the morphology of KCl, the KCl crystals were produced from glycine solution with different concentration (17–25% w/v) by evaporation at ambient temperature. The glycine (25% w/v)-modified KCl crystal changed its morphology from native cubic to hexagonal prism form with the angle of repose from 32° to 23.8–25.8°, indicating a good flowability and anticaking characteristics. Finally, KCl supersaturation variation with evaporation time was simulated with aid of the chemical model established in present study to elucidate the influence of glycine concentration on the anticaking characteristics of KCl crystal. All the results generated from this study will provide the fundamentals for industrial application to produce crystals with anticaking characteristics