• Membrane and Water Treatment
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• v.11 no.5
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• pp.353-361
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• 2020

The present study deals with a numerical investigation of heat and mass transfer in a Sweeping Gas Membrane Distillation (SGMD) used for desalination. The governing equations expressing the conservation of mass, momentum, energy and species with coupled boundary conditions were solved numerically. The slip boundary condition applied on the feed saline solution-hydrophobic membrane interface is taken into consideration showing its effects on profiles and process parameters.The numerical model was validated with available experimental data and was found to be in good agreement particularly when the slip condition is considered. The results of the simulations highlighted the effect of slip boundary condition on the velocity and temperature distributions as well as the process effectiveness. They showed in particular that as the slip length increases, the permeate flux of fresh water and process thermal efficiency rise.

• Journal of Mechanical Science and Technology
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• v.20 no.6
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• pp.840-848
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• 2006

We carried out numerical studies to investigate the single- and two-phase flow characteristics in the single- and multi-channels. We used the finite volume method to solve the mass and momentum conservation equations. The volume of fluid model is used to predict the two-phase flow in the channel. We obtained the distribution of velocity fields, pressure drop and air volume fraction for different water mass flow rates. We also calculated the distribution of mass flow rates in the multi-channels to understand how the flow is distributed in the channels. The calculated results for the single- and two-phase flow are partly compared with the present experimental data both qualitatively and quantitatively, showing relatively good agreement between them. The numerical scheme used in this study predicts well the characteristics of single-and two-phase flow in a multi-channel.

• Plant Biotechnology Reports
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• v.2 no.3
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• pp.213-218
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• 2008

Swertia chirata is an endangered gentian species that prefers to grow at higher altitudes. This ethnomedicinal herb is known primarily for its bitter taste caused by the presence of important phytochemicals that are directly associated with human health benefits. Due to a continuous loss of habitat and inherent problems of seed viability and seed germination, alternative strategies for propagation and conservation are urgently required to prevent the possible extinction of this species. We have formulated a reproducible protocol for the rapid propagation and conservation of this plant using leaves taken from in vitro shoot cultures. Direct induction of more than seven shoot buds per explant was achieved for the first time when the explants were placed on MS medium supplemented with $2.22{\mu}M$ N-6-benzyladenine, $11.6{\mu}M$ kinetin, and $0.5{\mu}M$ ${\alpha}-naphthalene$ acetic acid. Direct organogenesis was noted exclusively from the adaxial surface of the basal segments of leaves. Leaves closer to the apical meristem were more responsive than those farther away from the meristem. Plants raised through direct organogenesis were evaluated for their clonal fidelity by chromosomal analysis and DNA fingerprinting. Complete plants were successfully transferred to the field condition and produced viable seeds. Given the enormous potential of this age-old medicinal plant in terms of potential health-benefitting drugs, this protocol can be used for commercial propagation purposes and to initiate future genetic improvement studies.

• Journal of Conservation Science
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• v.34 no.2
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• pp.129-135
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• 2018

Scientific investigation of cultural heritage can provide important information to understand the context of the object. To know the characteristics of the material is also an essential part of objects management and conservation. However, the identification and characterization of organic dyes used in archaeological and historical textiles are often limited by the restrictions in sampling. To cope with the difficulties, applications of high-performance techniques of surface analysis, such as Time of Flight-Secondary Ion Mass Spectra (TOF-SIMS) could be considered as a non or micro-destructive option. This study aims to examine the applicability of TOF-SIMS analysis to the detection of organic dyes from historical textiles. A group of silk fabrics dyed with vegetable dyes were artificially photo-aged to different degrees and analyzed with TOF-SIMS. Molecular and fragment ions from indigo were successfully detected from the aged samples; however, only some fragment ions were observed from gardenia and safflower dyed fabrics. Further studies with actual historical samples with extended examination scope would be necessary to assess the validity of this technique.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.5
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• pp.180-188
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• 2010

This study was carried out to evaluate the analysis of environmental change (forest resources and soil water conservation by land types) after planting for prevention of between 2003 and 2006 from the stone hazarding areas in Guizhou province, China. Mean diameter growth of the trees was highest for Melia azedarach, followed by Robinia pseudoacacia, Lonicera fulvotomentosa, Choerospondias axillaris, Cupressus duclouxiana, and Eucommia uimoides Oliv. Mean height growth of the trees was greatest for R. pseudoacacia, followed by Ilex kudincha, M. azedarach, C. duclouxiana, C. axillaris, E. uimoides Oliv, Zanthoxylum bungeanum, and L. fulvotomentosa. Tree biomass was greater at the afforestation sites by 1.22-1.71 ton/ha compared to that of severely eroded mountain areas. The capacities of soil water conservation by land types were 2,790 ton/ha at latent rock desertification farmland, 2,655 ton/ha at rock desertification farmland, 1,680 ton/ha at dolomite sandstone hilly country, 1,650 ton/ha at halfstony hilly country, and 1,590 ton/ha at karst physiognomy site. Soil erosion was estimated to be 1,285 ton/$km^2$ which had been 2,178 ton/$km^2$ before afforestation. Also, we should be continuative manage after planting for prevention of the stone hazarding areas in Guizhou province, China.

• Nuclear Engineering and Technology
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• v.53 no.3
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• pp.732-740
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• 2021

Scattering resonance of medium mass nuclides leads complex spectrum in the fast reactor, which requires thousands of energy groups in the spectrum calculation. When the broad-group cross sections are collapsed, reaction rate cannot be completely conserved. To eliminate the error from energy collapsing, the Super-homogenization method in energy collapsing (ESPH) was employed in the fast reactor code SARAX. An ESPH factor was derived based on the ESPH-corrected SN transport equation. By applying the factor in problems with reflective boundary condition, both the effective multiplication factor and reaction rate were conserved. The fixed-source iteration was used to ensure the stability of ESPH iteration. However, in the energy collapsing process of SARAX, the vacuum boundary condition was adopted, which was necessary for fast reactors with strong heterogeneity. To further reduce the error caused by leakage, an additional conservation factor was proposed to correct the neutron current in energy collapsing. To evaluate the performance of ESPH with conservation factor, numerical benchmarks of fast reactors were calculated. The results of broad-group calculation agreed well with the direct full-core Monte-Carlo calculation, including the effective multiplication factor, radial power distribution, total control rod worth and sodium void worth.

• Journal of Plant Biotechnology
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• v.47 no.4
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• pp.330-336
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• 2020

Ex-situ conservation of the ornamental and medicinal orchid, Coelogyne stricta, was performed by mass propagation using seed culture. Propagation stages were optimized using full- and half-strength solidified MS medium with different phytohormones. Maximum seed germination (88 ± 0.5% over 6 weeks of culture) was achieved on half-strength MS medium supplemented with 15% coconut water. Maximum shoot numbers were found on full-strength MS medium supplemented with 1 mg/L BAP, 2 mg/L Kinetin, and 10% coconut water, while the longest root was developed on full-strength MS medium with 1.5 mg/L IBA. A 2:1:1 combination of coco-peat, pine bark, and sphagnum moss was found to be a suitable potting mixture resulting in 80% seedling survivability. The cytotoxic activity of extracts of both wild plants and in vitro-developed protocorms was determined using an MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay on a cervical cancer cell line. The wild plant extract inhibited the growth of 41.99% of cells, showing that this extract has moderate cytotoxic activity toward cervical cancer cells.

• Progress in Superconductivity and Cryogenics
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• v.20 no.3
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• pp.21-27
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• 2018

It is difficult to fabricate and maintain moving parts of expander at cryogenic temperature. This paper describes numerical analysis and experimental investigation on a cryogenic reciprocating expander without moving piston. An intake valve which takes high-pressure gas, and an exhaust valve which discharges low-pressure gas, are connected to a tube. The inside pressure of the tube is pulsated for work production. This geometric configuration is similar to that of pulse tube refrigerator but without regenerator. An orifice valve and a reservoir are installed to control the phase of the mass flow and the pressure. At the warm end, a heat exchanger rejects the heat which is converted from the produced work of the expanded gas. For the numerical analysis, mass conservation, energy conservation, and local mass function for valves are used as the governing equations. Before performing cryogenic experiments, we carried out the expander test at room temperature and compared the performance results with the numerical results. For cryogenic experiments, the gas is pre-cooled by liquid nitrogen, and then it enters the pulse tube expander. The experiments are controlled by the opening of the orifice valve. Numerical analysis also found the expander conditions that optimize the expander performance by changing the intake pressure and valve timing as well as the opening of the orifice valve. This paper discusses the experimental data and the numerical analysis results to understand the fundamental behavior of such a newly developed non-mechanical expander and elucidate its potential feature for cryogenic application.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.4
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• pp.313-320
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• 1995

A numerical analysis on the wave deformation in the shallow water region is performed for the case of two intersecting wave trains of the same frequency on uniformly sloping beaches. This model is based on the consideration of wave energy balance and wave action conservation, and iteratively solved the set of conservation equations of both mass and horizontal momentum. Using the computed results, the wave deformations in accordance with the variation of the parameters luck as incident wave angie and wave height in deep water which influences the variation of wave hight and mean water level under the intersecting wave trains in the shallow water region. are considered.

• Journal of Environmental Science International
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• v.13 no.1
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• pp.1-9
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• 2004

Regarding to the ecotourism for environmental conservation, tourists's consciousness and attitude on environment should be dealt with importantly more than the mass tourism. The purpose of this study is to identify the effects of the tourist's environmental consciousness on the ecotourism attitudes. As a result, it was analysed that the more people had interested in environmental problems, positive activities in the environment, the more people had the ecotourism attitudes. This suggested that for development of the ecotourism, it were needed to change tourist's attitude to friendly environment, to make higher consciousness about environmental conservation.