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Within this software, the CAD file is sliced into horizontal layers after the part is oriented for the optimum build position, and any necessary support structures are automatically detected and generated.
A primary modeler material is used to produce the model geometry and a secondary material, or release material, is used to produce the support structures.
The principle of the FDM (Fig. 1) is based on surface chemistry, thermal energy, and layer manufacturing technology.
Nemes, Porosity change by resin impregnation in structures obtained by selective laser sintering technology.
Slota, Influence of printing conditions on structure in FDM prototypes.

Moreover, the porous structure determined it very suitable to remove metal ions from aqueous solutions.
The scanning electron microscopy（SEM）photograph for the surface and bulk structures in Fig1, indicate that activated STW seem to possess sheet and layered structures with rough surfaces, meanwhile, it has a large number of mesopores on its surface, which facilitates the metal-ions adsorption on the STW and also speed up the mass transfer rate of releasing and rebinding of metal-ions.
When kinetic considerations are taken into account, the rapid adsorption kinetics can be attributed to the porous structure of the STW.
Acknowledgments This work was financially supported by the Open-ends Fund of Chemistry Cleaner Technology Key Laboratory of Jiaxing (No.70110107), and Technology and Innovation Fund for college student of Zhejiang Provice (No. 2010R417009 ) References [1] A.M.

The non-achievement of the sufficient strength can be an indicator of an improper micro structure of the solidification product (from the viewpoint of mineralogical-chemical composition) and imperfect hydration, from which the increased extraction of contaminants may result [6].
The compression strength of materials containing cement as a binder generally depends on the volume, size and structure of the pores.
The resulting strength depends on elements which cause a porous structure of material and less on hydration on products and their reaction to waste.
In one case, the disrupting of the specimen structure was throughout the whole volume of the sample, see Fig. 2.
Ballnerova, Ekotoxikologicke testy a jejich aplikace k hodnoceni vedlejsich energetickych produktu, Diploma thesis, BUT, Faculty of Chemistry,2008, pp. 8-19.

Window structures made of polyvinyl chloride compositions with microcalcite have been widely used for a long time, and, unlike wooden ones, have a lower thermal conductivity, are sealed and durable.
In addition, the investigated fillers contain both small and large fractions; therefore, such a particle size distribution will have a positive effect on the rheological properties, as well as on the structure of the resulting material.
Zagorodnikov, Investigation of the stress-strain state of a disperse-filled polymer composite using volumetric models, Mechanics of Composite Materials and Structures. 18(1) (2012) 16-34
Osipchik, The use of coal waste for filling PVC plastics, Advances in Chemistry and Chemical Technology. 18(3) (2004) 15-17
Hrnjak-Murgić Influence of calcium carbonate filler and mixing type process on structure and properties of styrene-acrylonitrile, Journal of Applied Polymer Science. 126(4) (2012) 1257-1266

Fresh coal gangue has stable crystal structure and the activity is poor, so that the utilization rate of coal gangue is lower [2,3].
Table 3 Results of sulphate resistance Samples Hydration time/d Flexural strength/MPa coefficient of corrosion resistance (R'/R0) uncorrosion /R0 corrosion/R' Cement with kiln dust-activated coal gangue 35 7.38 9.33 1.26 Portland cement 35 7.64 6.73 0.88 Sulphate corrosion may be caused by two fundamental aspects: (1) the crystalline expansion caused by calcium sulphate, produced by the reaction of sulphate and Ca(OH)2 in cement paste, to breakage the structure of concrete; (2) increase in volume caused by the translation of Ca(OH)2 into ettringite, to lead to the cracking and even breakage of concrete [8].
In addition, the "partical effect" of kiln dust-activated coal gangue also decreases the porosity and improves the structure of cement.
C-S-A-H gel with the Si-O-Al structure can restrain ASR by absorbing alkali ions (K +,Na +).
The chemistry of 'Alkali -aggregate' reaction[J].

Dybkov Department of Physical Chemistry of Inorganic Materials, Institute for Problems of Materials Science, Kyiv 03180, Ukraine vdybkov@ukr.net, vdybkov@ipms.kiev.ua Keywords: Interfacial interaction, diffusion, binary systems, compound layers, growth kinetics, sequence of occurrence.
The main factors affecting the mobility of atoms and hence the sequence of compound-layer formation are (i) melting points, Tm(A) and Tm(B), of components A and B, (ii) atomic radii, rA and rB, of those components, and (iii) crystal structures of the compounds.
A compound with the crystal structure providing preferable directions of diffusion of atoms may be expected to occur and grow first at the A-B interface (Fe2Al5 in Fe-Al, not FeAl3 or Fe2Al7).
As the layer growth takes place in diffusion couples under highly non-equilibrium conditions, formation of compounds with crystal structures of low symmetry is preferable.
Different portions of the same compound layer may even possess different structures (NiZn3-6 in Ni-Zn), with fresh portions having more low symmetry than those formed earlier.

The crystal structure, surface morphology and surface roughness are later characterized by means of X-ray diffraction, XRD (Bruker D8 Advance), field-emission scanning electron microscope, FESEM (JEOL JSM-7600F) and atomic force microscope, AFM (XE-100 Park Tenko), respectively.
Fig. 2(a) and Fig. 2(b) show the XRD spectra of CuO thin films indicate that they are crystalline in structure.
Fig. 3(a) reveals that at 5 kPa, large amount of oxide grains with inhomogeneous size and agglomerated CuO structures are formed.
It is believed that the formations of unaligned nanorods are due to the surface energy difference of the Cu-CuO films in the excess of O2 gas flow as supported by XRD evidence of two-phase structure, i.e Cu and CuO particles.
A special thanks to MiNT-SRC, Mechanical Engineering Laboratory and Science Chemistry Laboratory of Universiti Tun Hussein Onn Malaysia (UTHM) for providing such equipment and technical supports.

.) + Al2O3 + Fe2O3 19.37 18.68 16.18 25.98 m 2.48 2.39 3.21 2.27 – LOI – loss of ignition; IR – insoluble residue; m – modulus of hydraulicity (m=CaO+MgOSiO2+Al2O3+Fe2O3) The porosity, pore size distribution and pore structure are some of the most important properties that affect the water permeability of mortar.
In.: Materials, Technologies and Practice in Historic Heritage Structures, Berlin, 2010 p. 259–277
In: Abstracts of 10th International Congress on the Chemistry of Cement, Gothenburg, Sweden, 1997, Vol. 2, p. 52–55
Pore structure of historic and repair Roman cement mortars to establish their compatibility.
Pore structure and mechanical properties of cement–lime mortars.

Consequently, fullerene and carbon nanotubes (CNTs) have attracted the attention of many researchers due to their special structure since their discovery.
Single-wall carbon nanotubes made of a single layer cylindrical graphite structure have higher dispersion stabilizations as a result of smaller diameter size and less surface defects in contrast with multiwall carbon nanotubes.
The chemical structure of mineral oil is shown in Fig. 1.
(a)TEM image of SWCNTs; (b) The chemical structure of mineral 2.2 Preparation of nanorefrigeration oil The nanorefrigeration oil was prepared by dispersing nanopowders in the mineral lubricant through mechanical agitation and ultrasonication.
Carbon nanotube–polymer composites: Chemistry, processing, mechanical and electrical properties.

It reduced the total pore and capillary pore of the concrete, thus resulting in more dense structure [18].
The increased in the water absorption rate was due to the porous structure of the concrete provided by higher volume of bottom ash presents in the concrete.
Accordingly, water was easily diffused through the porous structure.
However, the decrease in strength for sample BA20, BA25 and BA30 is results from the porous structure of the concrete due to the higher amount of bottom ash.
Lea, The Chemistry of Cement and Concrete, third ed.