Wastewater containing heavy metals such as copper (Cu) and nickel (Ni) is harmful to humans and the environment due to its high toxicity. Crystallization in a fluidized bed reactor (FBR) has recently received significant attention for heavy metal removal and recovery. It is necessary to find optimum reaction conditions to enhance crystallization efficacy. In this study, the effects of crystallization reagent and pH were investigated to maximize crystallization efficacy of Cu-S and Ni-S in a FBR. CaS and Na2S·9H2O were used as crystallization reagent, and pH were varied in the range of 1 to 7. Additionally, each optimum crystallization condition for Cu and Ni were sequentially employed in two FBRs for their selective removal from the mixture of Cu and Ni. As major results, the crystallization of Cu was most effective in the range of pH 1-2 for both CaS and Na2S·9H2O reagents. At pH 1, Cu was completely removed within five minutes. Ni showed a superior reactivity with S in Na2S·9H2O compared to that in CaS at pH 7. When applying each optimum crystallization condition sequentially, only Cu was firstly crystallized at pH 1 with CaS, and then, in the second FBR, the residual Ni was completely removed at pH 7 with Na2S·9H2O. Each crystal recovered from two different FBRs was mainly composed of CuxSy and NiS, respectively. Our results revealed that Cu and Ni can be selectively recovered as reusable resources from the mixture by controlling pH and choosing crystallization reagent accordingly.

The crystallization of polypropylene (PP) particles in PP/decalin solution was conducted using the thermally induced phase separation(TIPS). During the control of particles sizes followed by the cooling of PP/decalin solution, particles were formed controllably, the concentrated PP resulted in an increase in the average diameter of PP particles. The effects of surfactants changes on particles sizes were investigated by using a field emission scanning electron microscope (FE-SEM). The PP crystals showed spherical shapes with a diameter 5∼18 μm. Additionally, as an effect of concentration of PP, the size distribution of the PP particles became broad with higher concentration of PP in the solution.

Generally, the color gold has had a biased conception due to its traditional use. Thus, this bias has resulted in alack of usage of golden glaze on ceramics and also a lack of extensive studies of such glazes. In this paper, optimum conditionsand mechanism of formation of gold color crystallization glaze containing Fe2O3(hematite), which is developed for gold colorsof ceramic glazes, were studied. Experimental result showed that there are pyroxene based on diopside and TiO2 phase in thebase of a crystallization glaze with a value of TiO2 of 6wt% confirmed by XRD and Raman Spectroscopy. When Fe2O3 wasused as a colorant for the gold color, the TiO2 peak became extinct and the intensity of the diopside peak was sharper. Feldsparof 60wt%, talc of 20wt% and limestone of 20wt% were used as the starting materials and these were tested using a threecomponent system. The best result of test was selected and extended to its vicinity as an experiment to determine TiO2 andFe2O3 contents. The glaze with TiO2 of 6wt% and Fe2O3 of 12wt% addition showed stable pyroxene based diopside crystalsand the development of gold color. This gold color was obtained with CIE-L*a*b* values of 51.27, 4.46, 16.15 (a grayishyellow brown color), which was gained using the following firing conditions: temperature increasing speed 5oC/min, holdingfor 1h at 1280oC, annealing speed 3oC/min till 1100oC, holding for 2h at 1100oC, and finally natural annealing.

우리는 decalin 용액으로부터 결정화 통해 선형 저밀도 폴리에틸렌 (LLDPE) 입자를 제조하였다. 열 유도 상 분리 (TIPS) 공정에서 입자의 형성은 LLDPE/decalin 용액을 제어하여 냉각하는 동안에 형성되었다. 높은 폴리머 농도에서 결정화를 위한 핵 생성과 성장속도의 증가에도 불구하고, 일반적으로 저 농도에서 보다 큰 입자를 초래하였으며, 결과적으로 LLDPE는 decalin 용액에서 농도가 증가할수록 LLDPE 입자의 평균 직경이 증가했습니다. FE-SEM 의 현미경사진에서, 다양한 농도로부터 관찰된 입자는 10 μm 보다 작았으며, 구형 형태를 나타내었다. 부가적으로 그 크기에 대한 효과를 보면, LLDPE 입자 크기 분포는 폴리머 농도가 높을 때가 폭이 컸다.

The formation of high-quality polycrystalline silicon (poly-Si) on relatively low cost substrate has been an important issue in the development of thin film solar cells. Poly-Si seed layers were fabricated by an inverse aluminum-induced crystallization (I-AIC) process and the properties of the resulting layer were characterized. The I-AIC process has an advantage of being able to continue the epitaxial growth without an Al layer removing process. An amorphous Si precursor layer was deposited on Corning glass substrates by RF magnetron sputtering system with Ar plasma. Then, Al thin film was deposited by thermal evaporation. An SiO2 diffusion barrier layer was formed between Si and Al layers to control the surface orientation of seed layer. The crystallinity of the poly-Si seed layer was analyzed by Raman spectroscopy and x-ray diffraction (XRD). The grain size and orientation of the poly-Si seed layer were determined by electron back scattering diffraction (EBSD) method. The prepared poly-Si seed layer showed high volume fraction of crystalline Si and<100> orientation. The diffusion barrier layer and processing temperature significantly affected the grain size and orientation of the poly Si seed layer. The shorter oxidation time and lower processing temperature led to a better orientation of the poly-Si seed layer. This study presents the formation mechanism of a poly seed layer by inverse aluminum-induced crystallization.

In this study, we are crystallized to the low density polyethylene (LDPE) micro-particles in n-dodecanol solution by thermally induced phase separation(TIPS) method. The Low density polyethylene micro-particles is used in a wide variety of polymer coatings and industrial application. The utility of that for a particular application depends on a number of factors such as the particle size and distribution, and chemical composition of the materials. However, there are still needs for new methods of preparation which will provide the structure with unique sizes. The widely used processes for micro-size particles are crystallization method and thermally induced phase separation. TIPS process based on the phase separation mechanism was performed for the LDPE system which undergoes liquid-solid phase separation. Effects of various operating parameters were examined on the structure variation of the particles. Professionality, take-up speed and crystallization rate depended on temperature and concentration of polymer in solution.

The effects of thermal properties on the crystallization behavior of CaMgSi2O6 glass-ceramics were investigated as a function of sintering temperature from 800˚C to 900˚C. The crystallization behavior of the specimens depended on the sintering temperature, which could be evaluated from the differential thermal analysis, X-ray diffraction and Fourier transform infrared spectroscopy. With increasing sintering temperature, the thermal conductivity of the sintered specimens increased, while the coefficient of thermal expansion (CTE) of the sintered specimens decreased. These results could be attributed to the increase of crystallization, confirmed from the estimation by density measurements. Also, the thermal diffusivity and specific heat capacity of the sintered specimens were discussed with relation to the sintering temperature. Typically, a thermal conductivity of 3.084 W/m˚C, CTE of 8.049 ppm/˚C, thermal diffusivity of 1.389 mm2/s and specific heat capacity of 0.752 J/g˚C were obtained for CaMgSi2O6 specimens sintered at 900˚C for 5 h.

Separation of naphthalene from naphthalene and 2-methylnaphthalene mixture has been studied by layered melt and solution crystallization using ethylalcohol. Purity and yield of naphthalene depended mainly on the cooling rate: The effective distribution coefficient (Keff) as the degree of impurity removal was observed to decrease with the decreasing in cooling rate. Purity of naphthalene can be enhanced to 5~7% by melt crystallization using 90% naphthalene and the purity of naphthalene can be obtained to be 99% up by solution crystallization.

A 532 nm Nd-YAG laser was applied to crystallize amorphous Si thin films in order to evaluate the applicability of a Nd-YAG laser to low-temperature polycrystalline Si technology. The irradiation of a green laser was controlled during the crystallization of amorphous Si thin films deposited onto glass substrates in a sophisticated process. Raman spectroscopy and UV-Visible spectrophotometry were employed to quantify the degree of crystallization in the Si thin films in terms of its optical transmission and vibrational characteristics. The effectiveness of the Nd-YAG laser is suggested as a feasible alternative that is capable of crystallizing the amorphous Si thin films.

In T-mixer crystallization, supersaturation is generated by mixing of another solvent or non-solvent in order to reduce the solubility of the compound. Also, T-mixer is a type of continuous crystallization. In order to induce micro-mixing, two solutions were mixed rapidly by T-mixer, which formed high supersaturation. As the results, mean size of HMX crystals decreased with increasing de-supersaturation rate (Rs). Eventually, HMX particles ranging from 0.5 to 5μm can be obtained by T-mixer crystallization. Mixing efficiency in T-mixer increased with increasing Rs values. In T-mixer crystallization without surfactants, homogeneous nucleation was formed when S and Rs was over 54 and 1.6×103/sec. In T-mixer crystallization with surfactants, homogeneous nucleation was formed when S and Rs was over 26 and 7.4/sec.

The reliability of innovative membrane contactors technology (i.e. Gas/Liquid Membrane Contactors, Membrane Distillation/Crystallization) is today increasing for seawater desalination processes, where traditional pressure-driven membrane separation units are routinely operated. Furthermore, conventional membrane operations can be integrated with membrane contactors in order to promote possible improvements in process efficiency, operational stability, environmental impact, water quality and cost. Seawater is the most abundant aqueous solution on the earth: the amount of dissolved salts covers about 3% of its composition, and six elements (Na, Mg, Ca, K, Cl, S) account for more than 90% of ionic species. Recent investigations on Membrane Distillation-Crystallization have shown the possibility to achieve significant overall water recovery factors, to limit the brine disposal problem, and to recover valuable salts (i.e. calcium sulphate, sodium chloride, magnesium sulphate) by combining this technology with conventional RO trains. In this work, the kinetics of CaSO4 ⋅ 2H2O, NaCl and MgSO4 ⋅7H2O crystallization is experimentally investigated in order to improve the design of the membrane-based crystallization unit.

The hydrogen sorption speeds of amorphous alloy and its crystallized alloys were evaluated at room temperature. amorphous alloy was prepared by ball milling. The hydrogen sorption rate of the partially crystallized alloy was higher than that of amorphous. The enhanced sorption rate of partially crystallized alloy was explained in terms of grain refinement that has been known to promote the diffusion into metallic bulk of the gases. The grain refinement could be obtained by crystallization of amorphous phase resulting in the observed increase in sorption property.

Co-Fe-Ni-B-Si-Cr based amorphous strips containing nitrogen were manufactured via melt spinning, and then devitrified by crystallization treatment at the various annealing temperatures of for up to 30 minutes in an inert gas atmosphere. The microstructures were examined by using XRD and TEM and the magnetic properties were measured by using VSM and B-H meter. Among the alloys, the amorphous ribbons of containing 121 ppm of nitrogen showed relatively high saturation magnetization. The alloy ribbons crystallized at showed that the grain size of alloy containing 121 ppm of nitrogen was about f nm, which exhibited paramagnetic behavior. The formation of nano-grain structure was attributed to the finely dispersed Fe4N particles and the solid-solutionized nitrogen atoms in the matrix. Accordingly, it can be concluded that the nano-grain structure of 5nm in size could reduce the core loss within the normally applied magnetic field of 300A/m at 10kHz.

NiTiZrSiSn bulk metallic glass powder was produced using inert gas atomization and then was sprayed onto a SS 41 mild steel substrate using the kinetic spraying process. Through this study, the effects of thermal energy of in-flight particle and crystallization degree by powder preheating temperature were evaluated. The deformation behavior of bulk metallic glass is very interesting and it is largely dependent on the temperature. The crystalline phase formation at impact interface was dependent on the in-flight particle temperature. In addition, variations in the impact behavior need to be considered at high strain rate and in-flight particle temperature.

We report the crystallization and magnetic properties of non-equilibrium alloy powders produced by rod-milling as well as by new chemical leaching. X-ray diffractometry, transmission electron microscopy, differential scanning calorimetry and vibrating sample magnetometry were used to characterize the as-milled and leached specimens. After 400 h or 500 h milling, only the broad peaks of nano bcc crystalline phases were detected in the XRD patterns. The crystallite size, the peak and the crystallization temperatures increased with increasing Fe. After being annealed at for 1 h for as-milled alloy powders, the peaks of bcc are observed. After being annealed at for 1 h for leached specimens, these non-equi-librium phases transformed into fcc Cu and phases for the x=0.25 specimen, and into bcc phases for both the x=0.50 and the x=0.75 specimens. The saturation magnetization decreased with increasing milling time for alloy powders. On cooling the leached specimens from ,\;the magnetization first sharply increase at about for x=0.25, x=0.50, and x=0.75 specimens, repectively.