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Introduction The advection-diffusion equation [1] is an important second-order linear partial differential equation (PDE) in physics, chemistry and other branches of science, such as the steady-state distribution of a passive substance dissolved in water and transported by the flow, transport of multiple reacting chemicals.
However, the construction of an appropriate mesh is not an easy task and sometimes the problems cannot be solved because of the lack of an appropriate mesh structure.
Substituting into , we have , , (4) , , (5) Combing with , this corresponds to a system of equations with an unsymmetrical coefficient matrix, structured in matrix form as (6) where , , .

Influence of Basalt Fibres and Aggregates on the Thermal Expansion of Cement-Based Composites KOŇÁKOVÁ Dana1,a *, ŠPEDLOVÁ Veronika1,b, ČÁCHOVÁ Monika1,c, VEJMELKOVÁ Eva1,d and ČERNÝ Robert1,e 1Czech Technical University in Prague, Faculty of Civil Engineering, Department of Materials Engineering and Chemistry, Thákurova 7, 166 29 Prague 6, Czech Republic adana.konakova@fsv.cvut.cz, bveronika.spedlova@fsv.cvut.cz, cmonika.cachova@fsv.cvut.cz, deva.vejmelkova@fsv.cvut.cz, ecernyr@fsv.cvut.cz Keywords: Concrete, basalt fibres, basalt aggregates, basic physical properties, thermal expansion.
References [1] Komonen, J., Penttala, V., Effects of high temperature on the pore structure and strength of plain and polypropylene fiber reinforced cement pastes, Fire Technology. 39 (2003) 23-34
[2] Černý, R., Podebradska, J., Totova, M., Toman, J., Drchalova, J., Rovnanikova, P., Bayer, P., Hygrothermal Properties of Glass Fiber Reinforced Cements Subjected to Elevated Temperature, Materials and Structures, 37 (2004) 597-607

Owing to the difference in structure of the ice and the minerals in the pore wall, direct contact would result in a high interfacial energy [20].
The crack tends to propagate through the boundary, which is the weak point in the structure.
Cogan and Setterstrom provided an excellent review of both the chemistry and uses of ethyl silicate and mention sites where it was applied to stone monuments in America [43].
Development of improved consolidants is important, because so many precious structures are already damaged by weathering and require remediation.
Brady (ed.): Physics and Chemistry of Mineral Surfaces (CRC Press, Boca Raton, FL, 1996) [6] S.

Different ceramic oxides (MexOy) i.e.: Al2O3, TiO2, SiO2 and ZnO2 were in situ co-deposited with Ag nanoparticles on the surface of RGO resulting in the formation of a nanocomposite structure of stacked flakes.
It can be seen that the RGO/MexOy-Ag composite flakes possessed the stack non-regular structures.
Olszyna, Morphology, structure, and photoactivity of two types of graphene oxide–TiO2 composites, Chem.
Honma, Enhanced Cyclic Performance and Lithium Storage Capacity of SnO2/Graphene Nanoporous Electrodes with Three-Dimensionally Delaminated Flexible Structure, Nano Lett. 9, 1 (2009) 72-75
Olszyna, Morphology, structure, and photoactivity of two types of graphene oxide–TiO2 composites, Chem.

Most of membrane experts try to achieve the goal of membrane manufacturing which is high selectivity and gas permeation flux with defect-free ultrathin dense layer of membrane structure.
In this quench step, the bulk of the membrane structure is formed and the remaining solvents and nonsolvents are extracted [9,10,11].
In recent years, sustainability, environmental concern and green chemistry have played a big role in guiding the development of the next generation materials, products, and processes.
In addition, due to the complete coalescence and fusion of dry phase-separated structure, nascent skin layer were matured.
Abdul Rahman, Effects of shear rate and forced convection residence time on asymmetric polysulfone membranes structure and gas separation performance, Sep.

The structure of Ce/TiO2 was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric and differential thermal analysis (TG–DTA) and DR UV-Vis.
Among the fabrication techniques, the templating method has become very useful in preparation TiO2 with specific structure and morphology [11, 15, 16].
Natural organisms with unique multi-level structure and morphology can be used to provide porous biotemplate in the preparation of hierarchical materials because of their advantages such as low cost, environment-friendly and widely distributed [16].
(°C) Fig. 3 TG–DTA profiles of as prepared 0.01-Ce/TiO2 It is well known the photocatalytic activity of a semiconductor is related to its photonic bandgap structure.
Collagen could be extended to synthesize different oxide nanocrystals with specifically structure and morphology.

The addition of pseudoboehmite promote the increase of the elasticity modulus evidencing the interaction of the pseudoboehmite with the polymeric matrix, probably modifying its crystalline structure.
The structure of a composite material is divided into: a) Matrix: the basis of the composite material, giving its structure and core properties.
The aluminum oxide changes into the hexagonal structure (α-alumina) does not happen directly, but through a process starting from boehmite (or from pseudoboehmite), going through a series of metastable phases following the sequence shown in equation 1 [10].
The chemistry of the sol-gel process is based on hydrolysis followed by condensation of the molecular precursors, that is, solutions of a metallic compound turned into solid mass.
The results are the average of 20 specimens Test Nanocomposite Thickness (mm) 3.31 ± 0.10 Width (mm) 10.06 ± 0.11 Energy (J) 0.13212 ± 0.01372 Energy (thickness) (J/m) 29.4979 ± 4.578 Energy f (area) (kJ/m²) 2.9316 ± 0.4542 Scanning Electron Micrograph (SEM) was used to analyze the structure of the pseudoboehmite utilized in the nanocomposite.

Rapid cooling rates in the fusion zone have resulted in martensitic structure and hardness also increased in proportional.
The chemistry of the steel is also adjusted accordingly to develop suitable strength of the steel.
Among these laser welding has gained industrial importance due to its high-power density, lower beam spot size, high rate of production, minimum distortion of welded structures.
Results and Discussion Microstructure and Mechanical Property Evaluation of Welded Joints: Weld structure of the through thickness section of the weld joints of three heat inputs (45 J/mm, 37.5 J/mm, and 30 J/mm) are shown in Figure 3.
Due to the rapid cooling, dendritic structure has been resulted in fusion zone.

SEM was used to characterize the pore structure and morphology.
This behavior confirmed the further crosslinking formation of polybenzoxazine structure.
It was observed that each cluster of the xerogel and carbon was composed of many tiny clusters aggregating together and generating pores less than one nanometer and dense structure.
During the phase separation process, the primary cluster will grow to form the bigger primary cluster, resulting in 3D interconnected structure [16].
Ishida: Journal of Polymer Science: Part A Polymer Chemistry.

., which could be employed for industrial solid lubricant due to the good friction-reducing characteristic of lamellar-structure FeS phase. 1.
Ferrous sulfide is an effective solid lubricant due to its hexagonal structure, low shear strength and high melting point (1373K), therefore the sulfide coating on the hard steel surface, even of several micro-meters thickness, could present an excellent friction-reducing effect and weaken the wear extent of its counterpart [1,2].
Scanning electron spectroscopy (SEM) and X-ray diffraction instrument (XRD) were employed to analyze the microstructure and phase structures of the sulfide coating on block sample.
Fig.4 shows the SEM morphology of the sulfide layer on Cr12 steel substrate, formed with the current density of 1.8A/dm 2 and the sulfurzing time of 30min. it reveals that the sulfide layer is a lamellar-structure and no transition zone existed in the substrate, which average sulfurcontent is approx 21 % by energy-dispersive X-ray (EDX).
(3) The FeS-phase coating is a lamellar-structure and no transition zone existed in the substrate.