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The thermodynamic and kinetic behaviors of coal gasification were studied via thermodynamic calculations and high-temperature simulation experiments. The results show that, at temperatures greater than 1173 K, the equilibrium concentrations of H2O(g) and CO2 are low and decrease with increasing temperature. With increasing CO2 volume fraction in the gas, the gas utilization rate gradually increases, and with increasing H2O(g) volume fraction, the rate gradually decreases. As the gasification temperature increases, the time required for completion of coal gasification is shortened, and the rate of coal gasification increases. The activation energies of internal diffusion and the interface reaction are 84.205 kJ/mol and 81.935 kJ/mol, respectively. In the early stage, the controlling factor of coal gasification is the interface reaction. As the reaction ratio increases, the controlling factor gradually changes from the interfacial reaction to internal diffusion. At 1173–1473 K, the controlling step of coal gasification is primarily the interfacial reaction.

A new method was studied for extracting manganese from low-grade pyrolusite with H2SO4 roasting and subsequent water leaching. The mechanism of roasting and optimal conditions for roasting, including the amounts of H2SO4 and H2O addition and the roasting temperature and time, were discussed. The results indicated that the pyrolusite roasting process in the temperature range of 400–600°C was controlled by internal diffusion. The apparent activation energies in the time ranges of 0–30 min and 60–240 min were 25.26 kJ/mol and 14.94 kJ/mol, respectively. The maximum extraction of Mn reached approximately 98%, and the minimum extraction of Fe was approximately 1% under the optimal conditions. The ferric ion concentration was below 0.05 g/L in the leaching solution; thus, Mn was effectively separated from Fe and Si.

This study investigated two different reaction modes with wet and submerged particles for accelerated carbonation of municipal solid waste incinerator (MSWI) bottom ash generated in the Republic of Korea. Additionally, the effects of the two reaction modes were examined in terms of the mineralogical change and leaching behavior of heavy metals during accelerated carbonation. The reaction modes were controlled with water-to-solid ratios of 0.3 and 10 L/kg for the wet and submerged particles, respectively. The CO 2 concentration was kept constant at 30%. The reaction temperature was held at 25 °C. The new, resulting compounds formed by the carbonation reaction in the wet condition precipitated as a thin coating around the bottom ash particles in what is called the carbonated-layer effect. The submerged condition resulted in the formation of only a negligible carbonated-layer. Moreover, the wet condition, due to the carbonated-layer effect, more effectively stabilized the leaching behavior of heavy metals than that of the submerged condition. However, unlike the submerged condition, this carbonated-layer effect did not result in the maximum value of CO 2 reacted with the bottom ash because it prevented the internal diffusion of CO 2 into the particles. The experimental data were fitted with theoretical functions derived from [1 − (1 − X t ) 1/3 ] n = k t. Here, k is the rate constant (h −1 ) of the carbonation reaction and X t is the carbonated fraction vs. time t .

Indoor releases of organic chemicals encapsulated in solid materials are major contributors to human exposures and are directly related to the internal diffusion coefficient in solid materials. Existing correlations to estimate the diffusion coefficient are only valid for a limited number of chemical-material combinations. This paper develops and evaluates a quantitative property-property relationship (QPPR) to predict diffusion coefficients for a wide range of organic chemicals and materials. We first compiled a training dataset of 1103 measured diffusion coefficients for 158 chemicals in 32 consolidated material types. Following a detailed analysis of the temperature influence, we developed a multiple linear regression model to predict diffusion coefficients as a function of chemical molecular weight (MW), temperature, and material type (adjusted R2 of 0.93). The internal validations showed the model to be robust, stable and not a result of chance correlation. The external validation against two separate prediction datasets demonstrated the model has good predicting ability within its applicability domain (R2ext > 0.8), namely MW between 30 and 1178 g/mol and temperature between 4 and 180 °C. By covering a much wider range of organic chemicals and materials, this QPPR facilitates high-throughput estimates of human exposures for chemicals encapsulated in solid materials. This article is protected by copyright. All rights reserved.

Coprocessing of bio-oil and petroleum fraction is a prospective way of bio-oil upgrading. The upgrading is a complex combination of kinetic and transport processes. An overall kinetic model was developed considering the internal diffusion and the catalyst deactivation in this paper. First, the parameters of intrinsic kinetics model were calculated by the experimental data obtained in a fixed-bed reactor with a fine powder catalyst particle (0.32 mm). Using the intrinsic kinetic parameters and gas–solid catalysis theory, an effectiveness factor model was developed to evaluate the effect of internal diffusion on coprocessing. Then the kinetic model rB=a×η×rB0 was established based on the effectiveness factor model and the deactivation rate equation. The effectiveness factor η and liquid yields at different reaction conditions predicted by this kinetic model agreed closely with the experimental results.

Epitaxial lateral overgrowth (ELO) over a free-standing dielectric mask is an unexplored territory in selective epitaxy growth (SEG) of semiconductors. By shrinking the dielectric mask dimension to the micron scale, the growth fronts from ELO are able to converge and coalesce, thus providing the freedom to engineer the interfacial structure between the epi-layer and dielectric mask. We demonstrate, herein, anomalous adatom diffusion and migration at the Ge/SiO

The KOH-capture reaction by coal fly ash at suspension-fired conditions was studied through entrained flow reactor (EFR) experiments and chemical equilibrium calculations. The influence of KOH-concentration (50–1000 ppmv), reaction temperature (800–1450 °C), and coal fly ash particle size (D50 = 6.03–33.70 μm) on the reaction was investigated. The results revealed that, at 50 ppmv KOH (molar ratio of K/(Al + Si) = 0.048 of feed), the measured K-capture level (CK) of coal fly ash was comparable to the equilibrium prediction, while at 250 ppmv KOH and above, the measured data were lower than chemical equilibrium. Similar to the KOH-kaolin reaction reported in our previous study, leucite (KAlSi2O6) and kaliophilite (KAlSiO4) were formed from the KOH-coal fly ash reaction. However, coal fly ash captured KOH less effectively compared to kaolin at 250 ppmv KOH and above. Studies at different temperatures showed that, at 800 °C, the KOH-coal fly ash reaction was probably kinetically controlled. At 900–1300 °C it was diffusion limited, while at 1450 °C, it was equilibrium limited to some extent. At 500 ppmv KOH (molar ratio of K/(Al + Si) = 0.481), and a gas residence time of 1.2 s, 0.063 g K/(g additive) and 0.087 g K/(g additive) was captured by coal fly ash (D50 = 10.20 μm) at 900 and 1450 °C, respectively. Experiments with coal fly ash of different particle sizes showed that a higher K-capture level were obtained using finer particle sizes, indicating some internal diffusion control of the process.

Two types of hydrothermally stable MOFs, ZIF-8 and MIL-53(Al) with different size and morphology, were prepared and used as supports for catalysts for synthesis of hydrocarbons from CO 2 hydrogenation. XRD patterns proves that all these two types of MOFs materials could be stable under the reaction conditions ( P = 3 MPa; T = 573 K) with water as byproduct. MOFs as a novel porous materials show excellent properties on catalysis compared with traditional supports γ-Al 2 O 3 and the type of MOF supports has a significant impact on the activity and selectivity of Fe catalysts for CO 2 hydrogenation. Due to the acidity of supports, ZIF-8 supports show different levels of considerable light olefins selectivity, while all MIL-53 supports nearly could not obtain light olefins. The light olefins selectivity of ZIF-8 is also affected by the secondary reaction of hydrogenation during the internal diffusion process. In this article, catalyst with high active and high light olefins selectivity was obtained just by modulating the MOFs supports.

Diffusion studies have rightly emphasized external ideas and resources that propel liberalization in the developing world. There remain two gaps: first, the literature has not covered the types of diffusers and the ways diasporas may shape liberalization in their homelands; second, it pays little attention to internal diffusion after national adoption within a country. This article explores the utility and conditions of diffusion by diasporas and examines the roles of diasporas and internal diffusion in China and India's FDI liberalization. In both countries, diasporas were main diffusers that led national adoption of liberalism at home. In China, however, entrepreneurial diasporas' networks with local governments helped expansive internal diffusion. India's professional diasporas did not strongly engage local governments or domestic companies. National adoption in India was followed by reversal and partial internal diffusions. India's software services provide a similar diffusion by diasporas to that in China.

The rate of ion exchange of Eu(III) from semi-infinite bath containing dilute nitric acid solution was studied on a macroporous bifunctional phosphinic acid resin. The influence of particle size, concentration of nitric acid and temperature on the uptake of Eu(III) was examined. The kinetic data were fitted into the Reichenberg approximate solution, based on the Nernst–Planck resin diffusion model, that relates the fractional attainment of equilibrium (Ut) and internal diffusion coefficient (DA). The measured DA was of the order of 10−13 m2/s, and it was found to increase with the increase of temperature, and decrease with the increase of particle size of the resin and concentration of nitric acid.

New multifilamentary Nb 3 Sn wires have been fabricated through an internal diffusion process using brass matrix. Brass has not only good elongation characteristics but also high yield strength more than double compared with Cu. Electron probemicroanalysis results show good interdiffusion between Sn and brass during the heat treatment. Zn remains homogeneously in the matrix after the Nb 3 Sn synthesis, expecting improvement of the mechanical strength of the wire. High mechanical strength would be preferable, particularly for react & wind magnet applications. Moreover, Zn seems effective to accelerate the Nb 3 Sn synthesis. The Nb 3 Sn layer in the brass matrix sample is more than 60% thicker than that in the reference Cu matrix sample. The thicker Nb3Sn layer accounts for the higher critical current density J c of the brass matrix sample. The B c2 of the wire is estimated to be about 25.5 T at 4.2 K. The volumetric ratio of Nb, Sn and Cu-Zn matrix has not yet optimized in terms of .Ic characteristics. The grain morphology of the Nb 3 Sn layer exhibits almost no difference between brass and Cu matrix samples. In order to improve the non-Cu .Ic characteristics, a newly designed wire has been developed.

The volatile evolution during thermal treatment of an oily sludge derived from petroleum refinery wastewater treatment plant was investigated by in-situ pyrolytic and kinetic analysis. According to kinetic mechanism model, it was found that the internal diffusion had a great influence on volatile release during 120–360 °C, while the devolatilization rate during 360–550 °C would more depend on the concentration of remaining hydrocarbons. By Py-GC/MS, oils were trapped and analyzed respectively during 60–360 °C and 360–550 °C, and above 300 compounds were identified and semi-quantified of the volatiles. During 60–360 °C, the detected volatile was mainly composed of saturated aliphatics, accounting for 68.69%. More proportion of light chain aliphatic hydrocarbons and monoaromtics were observed during 360–550 °C, and the relative content of unsaturated aliphatics increased to 33.81%. From the evolution profiles of typical oil products, the volatile release during 120–360 °C would follow the order of molecular weight. But during 360–550 °C, as a result of increasing thermal-cracking degree, the release peaks of the different volatile species were corresponded to similar temperature. The gaseous and sulfur-containing compounds were also traced. Among them, CO2 was the main product above 550 °C for the decomposition of minerals, and sulfur-containing compounds were mainly generated during

Highlights • Internal diffusion often controls the releases of flame retardants from microplastics. • Fick's law can describe the releases of additive flame retardants from microplastics. • Effects of temperature, plastic matrix, and particle size can be predicted by models. • Weathering of plastic matrix can greatly accelerate the releases of flame retardants. • Low fluxes of flame retardants released from microplastics pose no risk to ecosystem. The widely occurring debris of plastic materials, particularly microplastics, can be an important source of flame retardants, which are one of the main groups of chemicals added in the production of plastics from polymers. This review provides an overview on the use of flame retardants in plastic manufacturing, the kinetics of their releases from microplastics, the factors affecting their releases, and the potential environmental and ecosystem risk of the released flame retardants. The releases of flame retardants from microplastics typically involve three major steps: internal diffusion, mass transfer across the plastic-medium boundary layer, and diffusion in the environmental medium, while the overall mass transfer rate is commonly controlled by diffusion within the plastic matrix. The overall release rates of additive flame retardants from microplastics, which are dependent on the particle's geometry, can often be described by the Fick's Law. The physicochemical properties of flame retardant and plastic matrix, and ambient temperature all affect the release rate, which can be predicted with empirical and semi-empirical models. Weathering of microplastics, which reduces their particle sizes and likely disrupts their polymeric structures, can greatly accelerate the releases of flame retardants. Flame retardants could also be released directly from the microplastics ingested by aquatic organisms and seabirds, with physical and chemical digestion in the bodies significantly enhancing their release rates. Limited by the extremely slow diffusion in plastic matrices, the fluxes of flame retardants released from microplastics are very low, and are unlikely to pose significant risk to the ecosystem in general. More research is needed to characterize the mechanical, chemical, and biological processes that degrade microplastics and accelerate the releases of flame retardants and to model their release kinetics from microplastics, while efforts should also be made to develop environmentally benign flame retardants to ultimately minimize their risk to the environment and ecosystem.

A miniaturized analysis system based on a low power point discharge (PD) microplasma is described for mercury detection in Traditional Chinese Medicines (TCM) by chemical vapor generation atomic emission spectrometry (CVG-AES). The PD microplasma utilized a stainless-steel hollow needle as one of the electrodes, which also acts as the channel for the plasma gas and Hg vapor to enter the discharge region. This design allows the Hg vapor all transported and confined into the microplasma by internal diffusion, which helps to improve the sample introduction efficiency and excitation efficiency. Because of the efficient matrix separation by CVG, high selectivity and stability can be realized with this system. Under the optimized conditions, the limit of detection (LOD) was found to be 0.15 ng mL−1. The RSD (n = 7) was 2.7% for 5 ng mL−1 of Hg2+. The proposed technique has been applied to the investigation of Hg content in TCM drugs with satisfactory analytical results. The method provides several advantages including simple, high sensitivity, compactness and cost-effectiveness for mercury assay in TCM.

We show that Internal Diffusion Limited Aggregation (IDLA )on $\mathbb{Z} ^{d}$ has near optimal Cheeger constant when the growing cluster is large enough. This implies, through a heat kernel lower bound derived previously in [11], that simple random walk evolving independently on growing in time IDLA cluster is recurrent when $d\ge 3$.

Accidents in laboratory dealing with chemicals have constantly occurred. In the case of a gas explosion or an accident related to leakage of chemical materials, the damage is much greater, thereby leading to a serious accident. Especially, the safety of laboratory in University is important because students build up knowledge and skills and accumulate experience as the main researchers. In this paper, 5 gases(CO, , , , ) are selected to model since they are often used in university laboratories. From the scenarios where the gases are released, the diffusion process is estimated and analyzed to predict damage degree by PHAST v.6.7. Internal diffusion process is modeled through FLUENT which is Computational Fluid Dynamics(CFD) tool. Also, we compare indoor damage with outdoor one when discharged to the outside through the laboratory's window. In the modeling results, the outdoor damages for accident scenarios in the results are far less than then of real plants since the vessel usually used in laboratory(i.e. the capacity of the cylinder; 47 L or less) is significantly less than workplace's one(using ton measure). However as shown in the results small amount can have high consequences for indoor accidents.

Effects of plants' structures on bioactive compounds extraction were rarely reported, which limited the research improvement of extraction efficiency from an intrinsic perspective. In this work, the structural properties of untreated and steam exploded fig leaves as well as their effects on flavonoids extraction were systematically studied. Results implied that internal diffusion became the limiting factor of flavonoids extraction from untreated fig leaf when liquid-solid ratio exceeded 75 mL/g-dry. After steam explosion pretreatment (0.2 MPa and 3 mm), flavonoids yield extracted from fig leaf was increased by 55.9% compared with that from untreated fig leaf. However, more drastic steam explosion condition (0.4 MPa and 3 min) did not lead to higher flavonoids yield, which may be caused by the damage of flavonoids at high pretreatment temperature. A finite reaction model was proposed to demonstrate the mechanisms of flavonoids extraction from steam exploded fig leaf, and it was well consistent with the practical extraction. Therefore, steam explosion pretreatment with proper intensity should be a novel technology to enhance the extraction performance. (C) 2015 Elsevier B.V. All rights reserved.

The adsorption performance of pummelo peel to Rhodamine B (RhB) was tested to study the adsorption regulation and optimal adsorption condition of pummelo peel to dye waste water. The results showed that the RhB removal rate of 0.4 g pummelo peel to 100 mL 140 mg·L-1 RhB reached above 83 % under the condition of 30 °C, pH 8 and 60 min. The theroretical saturation adsorpion amount of pummelo peel was 133 mg·g-1 at 30 °C. The main adsorption pattern of pummelo peel to RhB was physical adsorption adsorption including external liquid film diffusion, surface adsorption and particle internal diffusion. The isothermal adsorption equation and secondary adsorption rate equation of Langmuir could be used to describe the adsorption process of pummelo peel to RhB.

A novel and facile strategy was proposed for precisely controlling the crystal size of ZIF-8, ZnCo bimetallic ZIFs and also NPs@ZIF-8 by separating the nucleation and growth. The fundamentals of crystallization of this strategy were elaborately investigated, and the size effect on the internal diffusion was explored for a series of Pt@ZIF-8 catalysts.

An experimental and computational study was performed to investigate the role of multi-component intra-NAPL diffusion on NAPL-water mass transfer. Molecular weight and the NAPL component concentrations were determined to be the most important parameters affecting intra-NAPL diffusion coefficients. Four NAPLs with different viscosities but the same quantified mass were simulated. For a spherical NAPL body, a combination of NAPL properties and interphase mass transfer rate can result in internal diffusion limitations. When the main intra-NAPL diffusion coefficients are in the range of self-diffusion coefficients (10-5 to 10-6 cm2/s), dissolution is not limited by internal diffusion except for high mass transfer rate coefficients (>180 cm/day). For a complex and relatively high viscous NAPL (>50 g/(cm s)), smaller intra-NAPL diffusion coefficients (

The capture of CO, a standard lung function test, results from diffusion-reaction processes of CO with hemoglobin inside red blood cells (RBCs). In its current understanding, suggested by Roughton and Forster in 1957, the capture is represented by two independent resistances in series, one for diffusion from the gas to the RBC periphery, the second for internal diffusion reaction. Numerical studies in 3D model structures described here contradict the independence hypothesis. This results from two different theoretical reasons: (i) The RBC peripheries are not equi-concentrations; (ii) diffusion times in series are not additive.

Food products with low water activity, dried, or frozen, are usually stored at non-equilibrium states, in which long-term stability cannot be assured. Changes in the storage conditions, including temperature and relative humidity, as well as internal diffusion of water and other compounds may affect the glass transition of foods, leading to deleterious effects on the product quality. The objective of this chapter is reviewing the main storage conditions that influence the glass transition of food materials, focusing on low-moisture and frozen products, in addition to discussing different approaches to applying in search of enhancing product stability and increasing shelf-life of foods.

Manganese oxide ores from Gabon and Xiangxi were leached with waste tea as reductant in dilute sulfuric acid solution. The effects of waste tea dosage, concentration of sulfuric acid, liquid-to-solid ratio, leaching temperature and reaction time on leaching process were explored. The leaching efficiency of Gabonese manganese oxide ore reached almost 100% under the optimal condition which was determined as follows: manganese oxide ore to waste tea mass ratio of 10:1, sulfuric acid concentration of 2.5 mol/L, liquid-to-solid ratio of 7.5:1, leaching temperature of 368 K, time of 8 h. The leaching efficiency of Xiangxi manganese oxide ore reached 99.8% under the optimal condition which was determined as follows: manganese oxide ore to waste tea mass ratio of 10:1, sulfuric acid concentration of 1.7 mol/L, liquid-to-solid ratio of 7.5:1, leaching temperature of 368 K, time of 8 h. The leaching process followed the internal diffusion controlled kinetic model, and the apparent activation energies of Gabonese manganese oxide ore and Xiangxi manganese oxide ore were calculated to be 38.2 kJ/mol and 20.4 kJ/mol, respectively. The morphological changes and mineralogical forms of the ore before and after the chemical treatment were discussed with the support of XRD analysis and SEM analysis.

본 연구의 목적은 국내 화력발전소에서 사용중인 인도네시아 석탄촤의 연소반응율을 연구하는 것이다. 석탄촤의 반응율은 External, Internal effectiveness factor를 고려하여 입자 내부 및 외부확산을 정량적으로 정리하였으며, Randompore model을 사용하여 탄소변환율에 따른 입자내부비표면적의 변화를 반영하였다. 가열 및 측정이 가능한 WHR(WireHeating Reactor)를 활용하여 반응시간을 측정함으로써 석탄촤의 반응율을 도출하였고 BET(Brunauer-Emmett-Teller)및 TGA(Thermo-Gravimetric Analysis) 장비를 활용하여 석탄촤의 물리적인 특성인 내부비표면적과 Random pore model의 구조변수(ψ)를 측정하였다. 석탄 종에 따른 활성화에너지 및 빈도인자를 도출하기 위해 아역청탄인 BARAMULTI,ENERGYMAN, AGM탄을 사용하였다. 본 연구 결과에서 External, Internal effectiveness factors를 통해 확산에 따른kinetics를 비교한 결과 외부 확산 보다 내부 확산의 영향이 지배적임을 확인하였다. 최종적으로 내부 및 외부 확산에대한 영향을 고려한 3종의 석탄촤 Intrinsic kinetics의 활성화에너지는 110~118 kJ/mol의 값을 보였다.Abstract −The experiment was designed to compare the char combustion kinetics of pulverized Indonesia coals com-monly utilized in Korea power plants. The reaction rate of coal char has been formulated using the external and internaleffectiveness factors to describe the diffusion effect quantitatively. The Random Pore Model (RPM) was used for apply-ing internal specific surface area as a function of carbon conversion ratio. Reaction rate was obtained from reaction timeusing the Wire Heating Reactor (WHR) which can heat and measure the char particle temperature at the same time. BETand TGA were used to obtain physical properties such as internal specific surface area and structural parameter. Threekinds of Indonesia Sub-bituminous coals “BARAMULTI, ENERGYMAN, AGM” were used in order to derive the acti-vation energy and pre-exponential factor. The results of this study showed that the effect of internal diffusion than that ofexternal diffusion is the dominant as comparison of kinetics was reflected in external and internal effectiveness factors.For three kinds of coal char, finally, activation energy of intrinsic kinetics indicates 110~118 kJ/mol. Key words: Coal Char, Reaction Rate, Kinetics, WHR, RPM

Sorption of U on strongly basic anion exchangers AMP, AM-p, Lewatit K6267, Lewatit MonoPlus MP600XL, Purolite A500u, and Purolite A600u was studied at various temperatures in batch and dynamic experiments. The dynamic exchange capacities, (g U) dm−3, of the anion exchangers to a breakthrough of 0.5 (mg U) dm−3 at 6–8°C were determined: AMP (9.56) > Purolite A600u (9.26) > Lewatit K6267 (9.13) > Purolite A500u, Lewatit MonoPlus MP600XL (8.87) > AM-p (5.88). Also, the total dynamic exchange capacities, (g U) dm−3, of the anion exchangers at 6–8°C were determined: AMP (37.13) > Purolite A500u (31.79) > Lewatit MonoPlus MP600XL (28.88) > Lewatit K6267 (27.74) > AM-p (27.58) > Purolite A600u (25.24). The concentration equilibrium distribution coefficients (K d) of U on these resins were determined in batch experiments. The highest value of K d = 2869 at 6°C and initial uranium concentration in solution of 65 mg dm−3 was attained with AMP of commercial grain-size distribution. At 24°C and the same uranium concentration, the highest value of K d = 5195 was obtained with separated 0.8–1.0-mm fraction of AMP. The kinetic experiments were performed, and the internal diffusion step was found to be the limiting step of the U sorption with all the resins under consideration. The internal diffusion coefficients in ion exchanger grains were calculated to compare the resins with each other.

This research addresses the theoretically neglected question of how the internal diffusion of inter-organizational systems (IOS) into a firm's activities and its external diffusion into the supply chain partners influence performance improvement. Drawing on the resource-based view, our research model posits that organizational and relational resources affect both internal and external diffusion, which in turn, influence performance improvement. Survey results from 187 managers in Korean and Chinese firms showed that while the impact of organizational resources on a firm's performance improvement was fully mediated by IOS diffusion, the diffusion partially mediates the impact of relational resources on performance improvement. This study also revealed a significantly different pattern of diffusion between Korean and Chinese firms, i.e. showing the impact of organizational and relational resources on a firm's performance through external diffusion of IOS are significantly greater in Korean firms, while the impact of internal diffusion was significantly greater in Chinese firms. In other words, Korean firms tend to externally diffuse IOS toward their business partners, while Chinese firms tend to internally diffuse IOS by deploying IOS from their partners. The implications of these findings for both research and practice are discussed.

Sorbent capacity and kinetics of the adsorption process on synthetic carbons (FAS grade) and commercial coconut shell activated carbons were studied in the system activated carbon-aqueous solution of sodium dicyanoaurate(I). The effect of progressive activation of carbons on the adsorption value was analyzed. The method of moments was used to calculate the internal diffusion coefficients and show their relation to the structure of activated carbons.

We build the iDLA cluster using drifted random walks, and study the limiting shapes they exhibit, with the help of sandpile models. For constant drift, the normalised cluster converges to a canonical shape S, which can be termed a true heat ball, in that it gives rise to a mean value property for caloric functions. The existence and boundedness of such a shape answers a natural yet open question in PDE theory., Comment: Corrected a number a typos and cleared up a few points in the proofs

Between 1890 and 1910, the town of Berlin, Ontario, adopted special-purpose bodies, such as water commissions and park boards, with enthusiasm. Why did Berlin’s civic leaders respond to these institutions so enthusiastically? This paper suggests that internal diffusion, fuelled by an argument about municipal capacity, was at work in Berlin at the time. The paper also critically examines two alternative explanations for the town’s enthusiasm, one grounded in Wilsonian reform, and the other in elite self-insulation., Entre 1890 et 1910, la ville de Berlin, en Ontario, a instauré avec enthousiasme des organismes spécialisés, tels que la commission des eaux et des parcs. Pour quelles raisons les dirigeants municipaux de Berlin ont-ils réagi de façon si enthousiaste à ces institutions ? Cet article suggère qu’un processus de diffusion interne, alimenté par un débat au sujet des compétences municipales, était à l’oeuvre dans Berlin à cette époque. L’article examine également deux explications que l’on donne de cet enthousiasme, la première fondée sur la réforme de Wilson, et la deuxième sur le mouvement d’isolation de l’élite.

DTA and TGA curves of titanium hydride powder were determined in air at different heating rates. Also the thermal decomposition behaviour of the aforementioned powder at high heating rates was taken into consideration. A great breakthrough of the practical interest in the research was the depiction of the P H2-time curves of TiH 2 powder at various temperatures in air. In accordance with the results, an increase in heating rate to higher degrees does not change the process of releasing hydrogen from titanium hydride powder, while switching it from internal diffusion to chemical reaction. At temperatures lower than 600 °C, following the diffusion of hydrogen and oxygen atoms in titanium lattice, thin layers TiH x phase and oxides form on the powder surface, controlling the process. On the contrary, from 700 °C later on, the process is controlled by oxidation of titanium hydride powder. In fact, the powder oxidation starts around 650 °C and may escalate following an increase in the heating rate too.

Microencapsulated rejuvenator has been attracted much attention for self-healing bitumen. The diffusion coefficient is one of the key parameters to estimate the feasibility of rejuvenator to age bitumen. The objective of this research was to evaluate diffusion behaviors of microencapsulated rejuvenator in aged bitumen by a FTIR-ATR method. Various microcapsule samples were mixed in bitumen to form thin films. The core material of microcapsules used as rejuvenator was diphenylsilane (DPS), its fairly specific absorption band at 843 cm−1 was selected as a marker band to calculate the diffusion coefficient (D). The microstructure parameters, including contents, mean size and mean shell thickness of microcapsules, were considered to understand the diffusion behaviors under different temperatures (20, 30, 40 and 50 °C) in bitumen. The results showed that a larger mean size of microcapsules did not greatly affect the D values under the same temperature. In contrast, a higher mean shell thickness decreased the D values because of the decrement of damage probability of microcapsules under the same content. With the same microcapsule sample in bitumen, the D values presented a trend of linear increase when the content of microcapsules was increased. All these results indicated that the microstructure affected the diffusion behaviors based on the concentration of released rejuvenator. A preliminary model of diffusion behaviors of microencapsulated rejuvenator in bitumen was given based on the Arrhenius equation considering the microstructure of microcapsules, the amount of released rejuvenator and the age degree of bitumen. This model may be a guide to the construction and application of self-healing bitumen using microcapsules.

The efficiency of using of the permeable composite membrane (PCM) is demonstrated in the 3-phase reaction of liquid substrate with gaseous hydrogen on solid catalyst (PCM acts as a catalytically active contactor)—hydrogenation of fatty acid triglyceride. PCM provides a good combination of the opposite requirements of mild internal diffusion restrictions, low hydraulic resistance, high thermal conductivity, well-developed gas–liquid interface and high catalyst loading in the reactor volume, and thus assures the control of the course of the catalytic reaction.