• Korean Journal of Environmental Agriculture
• /
• v.19 no.3
• /
• pp.218-222
• /
• 2000

Wasted${\cdot}$rested mine areas give lots of effect on around-environmental changes after mining development. Leaching water at reclaimed land has been eluted from the solid components through physical, chemical, biological procedures by waters percolated through reclaimed site. The element analysis of waste tungsten ore tailing, leaching water analysis and removal of heavy metal by zeolite were performed to investigate the influent of acid rain on the released contents of H. M. The heavy metal contents in leaching water were determined to be As $1.21\;{\sim}\;1.54\;ppm$, Pb $0.11\;{\sim}\;0.15\;ppm$ and $SO_4\;^{2-}$ was $302\;{\sim}\;378ppm$. As deionized water and simulated acid rain (pH 3,4) were percolated through columns packed tungsten ore tailing, the amount of Mn, Na, Ca which were dissolved by pH4 solution was higher than those by distilled water. However, W and Mo were eluted easily by high pH solution. The change of heavy metal concentration by column experiment packed zeolite was effective a little because heavy metals were adsorved much more by zeolite.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.14 no.2
• /
• pp.63-70
• /
• 2006

The purpose of this study was to develop the stability index of landfill sites to assess it's degree of stability. In order to develop the stability index, field data including leachate qualities, Landfill gas (LFG) composition and element composition of wastes from 50 closed landfills were collected. Three parameters-BOD/CODcr among leachate quality parameters, $CH_4$ among landfill gases, and C/N ratio from wastes-were found to be the best parameters for measuring the stability of landfill sites. The trend line of these parameters were used to Also, $CH_4$ from landfill gases and C/N ratio from wastes were found to be the best parameters. The trend lines of these parameters were used to develop the stability index of landfill sites. The equation for the index was as following; $I_{LS}=S_L+S_G+S_W$ $S_L=-\{4.892+16.587{\cdot}ln[BOD/COD_{Cr]\}$ $S_G=53.872-12.782{\cdot}ln[CH_4]$ $S_W=79.382-20.013{\cdot}ln[C/N]$ (The maximum score for $S_L$, $S_G$, and $S_W$ was 33.3.) where, $I_{LS}$ : The stability index of the landfill $S_L$ : The stability score of the leachate $S_G$ : The stability score of the landfill gas $S_W$ : The stability score of the waste.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.37 no.3
• /
• pp.531-539
• /
• 2017

The strut-tie model approach has been recognized as an efficient methodology for the design of all types of concrete members with D-regions, and the approach has been accepted in design codes globally. However, the design of concrete members with the approach requires many iterative numerical structural analyses, numerous graphical calculations, enormous times and efforts, and designer's subjective decisions in terms of the development of appropriate strut-tie model, determination of required areas of struts and ties, and verification of strength conditions of struts and nodal zones. In this study, a computer graphics program, that enables the design of concrete members efficiently and professionally by overcoming the forementioned limitations of the strut-tie model approach, is developed. In the computer graphics program, the numerical programs that are essential in the strut-tie model analysis and design of concrete members including finite element analysis programs for the plane truss and solid problems with all kinds of boundary conditions, a program for automatic determination of effective strengths of struts and nodal zones, and a program for graphical verification of developed strut-tie model's appropriateness by displaying various geometrical shapes of struts and nodal zones, are loaded. Great efficiency and convenience during the application of the strut-tie model approach may be provided by the various graphics environment-based functions of the proposed program.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.38 no.2
• /
• pp.110-118
• /
• 2002

The element free Galerkin method has been suggested by Belyschko, etc. it is applied for linear elastic analysis of solid problems and its convergence characteristics and stability are shown according to the weight function, influence domain and scattered points. The various numerical examples are performed to check the efficiency of 1D EFG and 2D EFG program by changing factors. As a result it have the best results when it used the cubic spline weight function and the scaling parameter d$_{max}$=2. These programs were developed by mixed language programming method using Visual Basic and the C language. so it is fast and efficient. and visually shown the result.t.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.2 no.2
• /
• pp.97-104
• /
• 2004

Neutron induced prompt gamma-ray spectroscopy(NIPS) system measures the prompt gamma-ray emitting by the interaction of a neutron with various materials. This system will be of great benefit to scientists worldwide, since it provides the non-destructive measurement of many element in either solid or liquid wastes. In this study, the full-energy-peak (FEP) efficiency calibration for a HPGe detector was constructed in the ${\gamma}$-ray energy range from 80 keV to 8 MeV, using $^{l33}$Ba and >TEX>$^{152}Eu$ RI sources and $ ^{35}Cl(n, ${\gamma}$)^{36}Cl$ thermal neutron captured reaction. The FEP efficiency curve for the higher energies using the $^{35}Cl(n, ${\gamma}$)^{36}Cl$ reaction was normalized with the curve obtained from the RI sources, since the accurate activity of its prompt ${\gamma}$-ray is unknown. The average thermal neutron flux was theoretically calculated using the FEP efficiency curve for the KCl standard solutions. The NIPS system equipped with a ${\gamma}$-${\gamma}$ coincidence setup with two n-type coaxial HPGe detectors was considered in order to reduce the interfering ${\gamma}$-ray background. The FEP efficiency curve for the ${\gamma}$-${\gamma}$ coincidence system was also obtained for full energy range. The performance of the normal and coincidence NIPS system was tested by comparing signal-to-noise ratio in each mode using the reference sample.e.

• Resources Recycling
• /
• v.24 no.5
• /
• pp.15-21
• /
• 2015

Waste plastic differs in its speed of combustion owing to its variety in composition as well as kinds of plastic. This study is aimed at examining the thermal weight analysis and determination of its kinetics in order to derive the design element in pyrolysis of RPF (Refused Plastic Fuel) as the plastic solid fuel. Based on the result of TGA (Thermogravimetric analysis), kinetic characteristics were analyzed by using Kissinger method which are the most common method for obtaining activation energy, and experimental conditions of TGA were set as follows: in a nitrogen atmosphere, gas flow rate of 20 ml/min, heating rate of $5{\sim}50^{\circ}C/min$, and maximum hottest temperature of $800^{\circ}C$. The method used for determining the property of waste plastic when thermally decomposed was thought feasible as the basic data in deciding the performance, design, and optimal operating condition of the reactor in the actual reactor.

• Journal of the Korean Magnetics Society
• /
• v.4 no.3
• /
• pp.226-232
• /
• 1994

Rapidly solidified $SmFe_{7+x}M_{x}(M=Mo,\;V,\;Ti)$ compound were found to crystallize in the ${Sm(Fe,\;M)}_{7}$ based stable magnetic phase by introducing a second transition element into the Sm-Fe binary system. The ${Sm(Fe,\;M)}_{7}$ phase exhibits the highest Curie temperatuer ($T_{c}=355^{\circ}C$) ever Known in the Sm-Fe magnetic systems with a quite high intrinsic coercivity($_{i}H_{c}=3~6\;kOe $). The ${Sm(Fe,\;M)}_{7}$ phase remains stable even after annealing if once form during the rapid solidification. The primary reason for the high coercive force is due to the fine grain size($2000~8000\;{\AA}$)of the magnetic ${Sm(Fe,\;M)}_{7}$ matrix phase, and the enhanced Curie temperature is attributed to the extended solid-solubility of the additive transition elements in Fe matrix, which leads to volume expansion of the ${Sm(Fe,\;M)}_{7}$ cell causing an enhanced coupling constant of Fe atoms.

• Journal of Korean Association for Spatial Structures
• /
• v.4 no.2 s.12
• /
• pp.63-71
• /
• 2004

The structural space is gradually wide and is wanting agreeable environment by the requirement and necessity of people who lives modem stage. The building coincides with such requirements and is the high rise building actual circumstances which is doing ultra-large. The confirmed report of the technology to organize great merit is becoming currently considerably important issue in constructing a building field. Thus, this paper examine closely for nonlinear unstable taking a picture uneasiness height of prosperity considering to initial imperfection by a numerical method with a space frame structure of discrete system in large space structure. Based on previous investigation method, this paper induce nodal stiffness matrix of solid truss elements considering geometrical nonlinear using finite element method. In this paper, three types of space structure considered; i) 1-free node space structure, ii) 2-free node space structure, iii) multi-free node space structure. It apply the above examples to a nonlinear program, next, grasp the characteristic of an unstable conduct and the result was a clearing low.

• Korean Journal of Social Welfare
• /
• v.65 no.2
• /
• pp.103-130
• /
• 2013

Although both ecosystem theory and empowerment have become the most prevalent candidate for integrated paradigm for social welfare practices, they could not overcome completely the long-standing and sharp divides between micro and macro practices, that is, between subject and structure as a main explanatory element in social welfare realm. Along with such traditional dualism and tension, a new emerging divide between modernism and postmodernism regarding intrinsic mission and roles of social welfare has urged strongly to develop the overarching theoretical framework for social welfare practice. In this regard, this study aims to recast the ecosystem theory and empowerment through the reflexive modernization theory of critical sociologist Anthony Giddens. With relatively strong emphasis on human capability coined as the reflexivity, Giddens's own creative theory of modernization can be thoroughly expected to provide a solid foundation of integrated paradigm enough to bridge the existing dualisms in social welfare theory and practice. Especially, his unique account of integrated way of how human agency is involved in the construction of social structure and how to transform each other recursively has profound implication for empowerment to be adequate and proper comprehensive framework for social welfare practice.

• Korean Journal of Materials Research
• /
• v.8 no.9
• /
• pp.860-864
• /
• 1998

We investigated the photoluminescence and the crystalline properties with Ga doping concentrations (0-12 mol%) in $\textrm{Zn}_{1.98}\textrm{Mn}_{0.02}\textrm{SiO}_{4}$ green phosphors prepared by the solid state reaction. The photoluminescence was improved by a doping of Ga element in $\textrm{Zn}_{1.98}\textrm{Mn}_{0.02}(\textrm{Si_{1-x}\textrm{Ga}_{x})\textrm{O}_{4}$ phosphors which showed the highest emission intensity and good color purity in the doping concentration of x=0.08. The emission intensity of $\textrm{Zn}_{1.98}\textrm{Mn}_{0.02}(\textrm{Si_{1-x}\textrm{Ga}_{x})\textrm{O}_{4}$(x= 0.08) phosphors was increased to 7 times with increasing the sintering temperatures from $1100^{\circ}C$ to $1400^{\circ}C$, showing the improved crystalline quality. The decay time was not affected by Ga doping concentrations with constant values around 24ms. It was found from SEM and PSA analyses that the phosphors were composed of a large number of small grains around 1-3$10\mu\textrm{m}$ with a small amounts of agglomerated particles above $10\mu\textrm{m}$.