Researchers are in continuous search of better strategies to minimize, if not prevent, the anthro... more Researchers are in continuous search of better strategies to minimize, if not prevent, the anthropogenic release of toxic heavy metals, such as Cu(II) and Pb(II), into drinking water resources and the natural environment. Herein, we report for the first time the low-temperature combustion synthesis of magnetic chitosan-manganese ferrite in the absence of toxic cross-linking agents and its removal of Cu(II) and Pb(II) from single-component metal solutions. The nonlinear Langmuir model best described the isotherm data, while the nonlinear pseudo-second order model best described the kinetic data, signifying monolayer Cu(II) or Pb(II) adsorption and chemisorption as the rate-determining step, respectively. Adsorption capacities by magnetic chitosan-manganese ferrite obtained for both metals were consistently higher than those by manganese ferrite, indicating that chitosan enhanced the performance of the magnetic adsorbent. The maximum adsorption capacities of magnetic chitosan-manganes...
The primary purposes of this study are to investigate the feasibility of electrochemical depositi... more The primary purposes of this study are to investigate the feasibility of electrochemical deposition treatment (EDT) as a comprehensive rehabilitation method for corrosion-induced deterioration in reinforced concrete with various severity levels, and to propose a guideline for the determination of critical factors to advance EDT. This study includes three experimental phases, each of which simulates the initiation (de-passivation), propagation (high corrosion activity), and acceleration (formation of a surface-breaking crack) periods of corrosion-induced deterioration. After completion of a series of accelerated corrosion tests, damaged concrete samples with different severity levels are rehabilitated by a series of EDT processes using a MgCl2 solution in an electrolyte. The main variables for this experiment are the concentration levels (0, 0.3, 1.0 and 3.0 M) of a MgCl2 solution for test phase 1, charging time (0, 2, and 7 days) in EDT for test phase 2, and configuration of pre- an...
The main objective of this research is to investigate the effect of water content in concrete on ... more The main objective of this research is to investigate the effect of water content in concrete on the velocities of ultrasonic waves (P- and S-waves) and mechanical properties (elastic modulus and compressive strength) of concrete. For this study, concrete specimens (100 mm × 200 mm cylinders) were fabricated with three different water-to-binder ratios (0.52, 0.35, and 0.26). These cylinders were then submerged in water to be saturated in different degrees from 25% to 100% with an interval of 25% saturation. Another set of cylinders was also oven-dried to represent the dry condition. The dynamic properties of concrete were then assessed using a measurement of elastic wave accordance with ASTM C597-16 and using resonance tests following ASTM C215-19, before and after immersion in water. The static properties of saturated concrete were also assessed by the uniaxial compressive testing according to ASTM C39/C39M-20 and ASTM C469/C469M-14. It was observed that the saturation level of con...
International Journal of Environmental Research and Public Health
This case study covers the application of the fuzzy optimization in simultaneously satisfying var... more This case study covers the application of the fuzzy optimization in simultaneously satisfying various constraints that include the compliance of ammonia and nitrate concentrations with stringent environmental standards. Essential components in the multi-criteria decision-making analysis is in the utilization of the Box-Behnken design (BBD) response equations, cost equations and the cumulative uncertainty of response towards the sodium chloride dosage, current density and electrolysis time parameters. The energy consumption in the electrochemical oxidation of ammonia plays an essential role in influencing the total operating cost analysis. The determination of boundary limits based on the global optimum resulted in the complete ammonia removal and USD 64.0 operating cost as its maximum boundary limits and the 40.6% ammonia removal and USD 17.1 as its minimum boundary limits. Based on the fuzzy optimal results, the overall satisfaction level incurred a decrease in adhering with a lowe...
The widespread presence of heavy metals in drinking water sources arises as a major health concer... more The widespread presence of heavy metals in drinking water sources arises as a major health concern, particularly in developing countries. The development of low-cost and reliable detection techniques is identified as a societal need to provide affordable water quality control. Herein, a bismuth film-coated gold ultramicroelectrode array (BF-UMEA) was used for the detection of Pb(II) and Cd(II) in water samples via square wave anodic stripping voltammetry (SWASV). Experimental parameters such as deposition time, Bi(III) concentration, acetate buffer concentration, pH, square wave frequency, amplitude, and step potential were all varied to determine their effects on the current peak intensities of the target metal ions. Ten-fold excess in the concentration of interferences was found to cause a decrease in the stripping peak areas of Cd(II) and Pb(II) in the following order of magnitude: benzene < NaCl < Ni(II) < Cu(II). Using Box–Behnken design, the optimum SWASV parameters t...
The main objectives of this research are to evaluate the effects of delamination defects on the m... more The main objectives of this research are to evaluate the effects of delamination defects on the measurement of electrical resistivity of reinforced concrete slabs through analytical and experimental studies in the laboratory, and to propose a practical guide for electrical resistivity measurements on concrete with delamination defects. First, a 3D finite element model was developed to simulate the variation of electric potential field in concrete over delamination defects with various depths and lateral sizes. Second, for experimental studies, two reinforced concrete slab specimens (1500 mm (width) by 1500 mm (length) by 300 mm (thickness)) with artificial delamination defects of various dimensions and depths were fabricated. Third, the electrical resistivity of concrete over delamination defects in the numerical simulation models and the two concrete slab specimens were evaluated by using a 4-point Wenner probe in accordance with AASHTO (American Association of State Highway and Tr...
The primary objective of the present work is to measure the corrosion rate of reinforcing steel e... more The primary objective of the present work is to measure the corrosion rate of reinforcing steel embedded in concrete structures in a simulated marine environment of high chloride concentration. The selection of a single frequency that corresponds to the solution resistance and single frequency that corresponds to the charge transfer resistance were performed and measurements were carried out in a relatively faster time. A total of seven cement mortar specimens were prepared. The effect of varying cover thickness (5–50 mm) and rebar distance (10–80 mm) on the electrical resistance of the concrete and corrosion rate of the steel was examined. To simulate the corrosion of reinforced concrete in a marine environment, cement mortars were exposed to 25 wet–dry cycles that involve an immersion for 8 h in 3 wt.% NaCl solution and drying time of 16 h under room temperature. Alternative current (AC) impedance measurements were carried out within a frequency range from 100 kHz to 1 mHz. Results show that the formation of rust layers on rebars has caused a significant decrease in the maximum phase shift to θ = −30°. An accelerated corrosion rate of the rebars was observed during drying stage.
In this paper, the synthesis of a chitosan–montmorillonite nanocomposite material grafted with ac... more In this paper, the synthesis of a chitosan–montmorillonite nanocomposite material grafted with acrylic acid is presented based on its function in a case study analysis. Fuzzy optimization is used for a multi-criteria decision analysis to determine the best desirable swelling capacity (YQ) of the material synthesis at its lowest possible variable cost. For YQ, the integrating the result’s cumulative uncertainty is an essential element to investigate the feasibility of the developed model equation. The Pareto set analysis is able to set the appropriate boundary limits for YQ and the variable cost. Two case studies are presented in determining the lowest possible cost: Case 1 for maximum YQ, and Case 2 for minimum YQ. These boundary limits were used in the fuzzy optimization to determine its global optimum results that achieved the overall satisfaction ratings of 67.2% (Case 1) and 52.3% (Case 2). The synthesis of the polyacrylic acid/chitosan material for Case 1 resulted in 305 g/g YQ...
Journal of Architecture, Planning and Environmental Engineering (Transactions of AIJ)
A novel OPTIMAL sCheme based on the second − order interpolation tecnique is proposed for highly ... more A novel OPTIMAL sCheme based on the second − order interpolation tecnique is proposed for highly accurate and noh ． oscilatory simulation of convection ． The effectiveness of this s (heme is demon − strated through applications of several scalar tra皿 3port problems in twq − dimensiollal lamina エ and l turbulent recirculating flow ． The results are compared to currently avaiable schemes such as PLDS ， QUICK， LODA ， ULTRA − SHARP etc ． ， and the8e result8 demonstrate that the bouhded OPTIMAL and tlie boullded LODA with local full upwinding can give accurate and wiggle free solutions with prQperly designed coarse mesh layout ． Howevel， the OPTIMAL evidently appears advantag θ ous for practical apphcations because of its oomputational simphcity
Bathymetric mapping is traditionally implemented using shipborne single-beam, multi-beam, and sid... more Bathymetric mapping is traditionally implemented using shipborne single-beam, multi-beam, and side-scan sonar sensors. Procuring bathymetric data near coastlines using shipborne sensors is difficult, however, this type of data is important for maritime safety, marine territory management, climate change monitoring, and disaster preparedness. In recent years, the bathymetric light detection and ranging (LiDAR) technique has been tried to get seamless geospatial data from land to submarine topography. This paper evaluated the accuracy of bathymetry generated near coastlines from satellite altimetry-derived gravity anomalies and multi-beam bathymetry using a tuning density contrast of 5000 kg/m3 determined by the gravity-geologic method. Comparing with the predicted bathymetry of using only multi-beam depth data, 78% root mean square error from both multi-beam and airborne bathymetric LiDAR was improved in shallow waters of nearshore coastlines of the western Korea. As a result, the sa...
In the present research, treatment of contaminated groundwater via adsorption of As(V) with an in... more In the present research, treatment of contaminated groundwater via adsorption of As(V) with an initial concentration of 50.99 µg/L using chitosan-coated bentonite (CCB) was investigated. The effect of adsorbent mass (0.001 to 2.0 g), temperature (298 to 328 K), and contact time (1 to 180 min) on the removal efficiency was examined. Adsorption data was evaluated using isotherm models such as Langmuir, Freundlich, and Dubinin-Radushkevich. Isotherm study showed that the Langmuir (R2 > 0.9899; χ2 ≤ 0.91; RMSE ≤ 4.87) model best correlates with the experimental data. Kinetics studies revealed that pseudo-second order equation adequately describes the experimental data (R2 ≥ 0.9951; χ2 ≤ 0.8.33; RMSE ≤ 4.31) where equilibrium was attained after 60 min. Thermodynamics study shows that the As(V) adsorption is non-spontaneous (ΔG0 ≥ 0) and endothermic (ΔH0 = 8.31 J/mol) that would result in an increase in randomness (ΔS0 = 29.10 kJ/mol•K) within the CCB-solution interface. FT-IR analysis...
In the present work, graphene oxide (GO) was synthesized via the modified Hummers method and util... more In the present work, graphene oxide (GO) was synthesized via the modified Hummers method and utilized in treating real soil washing wastewater via adsorptive removal of lead (Pb) and zinc (Zn). Characterization analysis of GO was performed using X-ray diffraction, Brunauer-Emmett-Teller method, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and zeta potential analysis. The Van’t Hoff, Eyring, and Arrhenius equations were applied to determine the activation and thermodynamic parameters namely activation energy (Ea), standard Gibbs energy change (ΔG°), standard enthalpy change (ΔH°), standard entropy change (ΔS°), change in activation Gibbs energy (ΔG#), change in activation enthalpy (ΔH#), and change in activation entropy (ΔS#). Based on the high coefficient of determination values (0.8882 ≥ R2 ≥ 0.9094) and low values of SSE (0.0292 ≤ SSE ≤ 0.0511) and ARE (0.8014 ≤ ARE ≤ 0.8822), equilibrium data agreed well with the Freundlich isotherm. The maximum adsorption capacity for Pb(II) and Zn(II) was determined to be 11.57 and 4.65 mg/g, respectively. Kinetic studies revealed that pseudo-second-order equation fitted well with the experimental data, which indicates that chemisorption is the rate-determining step of the adsorption system. Results have shown the possibility of GO as a potential adsorbent material in the treatment of soil washing wastewater.
In the present work, the performance of spent coffee grounds (SCG) as an adsorbent in the treatme... more In the present work, the performance of spent coffee grounds (SCG) as an adsorbent in the treatment of real soil washing wastewater (SWW) was evaluated. Scanning electron microscopy, Fourier transform infrared spectroscopy, zeta potential measurement and Brunauer–Emmett–Teller analysis were utilized to determine the physicochemical characteristics of SCG. Maximum removal efficiency of 68.73% for Cu(II), 57.23% for Pb(II) and 84.55% for Zn(II) was attained at 2.5 g SCG, 300 min and 328 K. Error analysis was performed using root mean square error (RMSE) and sum of square error (SSE). Equilibrium data correlated well with the Langmuir isotherm for Pb(II) adsorption and Freundlich model for the removal of Cu(II) and Zn(II). The kinetic study shows that adsorption of the heavy metals using SCG can be satisfactorily described using the pseudo-second order equation (R2 ≥ 0.9901; RMSE ≤ 15.0539; SSE ≤ 145.1461). Activation parameters including activation energy, change in free energy of act...
AS t u d yo nt h eE n e r g yC o n s u mp t i o nC h a r a c t e r i s t i cb yBu i l d i n gE n ... more AS t u d yo nt h eE n e r g yC o n s u mp t i o nC h a r a c t e r i s t i cb yBu i l d i n gE n v e l o p eo f Ap a r t me n tHo u s i n gi nBu s a nMe t r o p o l i t a nCi t y 이정재* ․김환용* * †․김승희* * * Y e eJ u r n g-J a e * ,K i m H w a n-Y o n g * * †a n dK i m S e u n g-H e e * * * (S u b mi td a t e:2 0 1 4 .6 .2 3. ,J u d g me n td a t e:2 0 1 4 .6 .2 3. ,P u b l i c a t i o nd e c i d ed a t e:2 0 1 4 .8 .2 5 .
Abstract In this study, an Energy Integrated Support System (EnerISS) Modeler (or simply, Modeler... more Abstract In this study, an Energy Integrated Support System (EnerISS) Modeler (or simply, Modeler), an automated module of a knowledge-based urban planning support system, was developed to support the strategic technology implementation of environmentally friendly local energy planning. Modeler was developed as a tool that integrates various formats of the planning data into a unified format during the planning stage. It automates the three-dimensional (3D) modeling of the integrated urban space and presents visual information to support decision-making processes. The system architecture of Modeler includes the formation of building polygons, textures for classified land cover shape, topography, and 3D urban space. Modeler was developed on a native-based software (S/W) platform. It was created with a single document frame (SDF) from the Windows Microsoft Foundation Class (MFC) Library and is driven by a 3D-based engine that can be used by a GIS client. Modeler was validated for a domestic city in the urban planning stage on a test bed platform. Because of the expansion of a ubiquitous environment and increasing social network services (SNS), the ability to port the Modeler to a web-based platform should be investigated, thus enabling easier access for decision makers.
* 동의대학교 대학원 건축공학과(i c d i e 0 0 @n a v e r. c o m) ,* * 동의대학교 건축설비공학과(p y o o l @d e u. a c. k r)... more * 동의대학교 대학원 건축공학과(i c d i e 0 0 @n a v e r. c o m) ,* * 동의대학교 건축설비공학과(p y o o l @d e u. a c. k r) , * * * 동아대학교 건축공학과(j j y e e @d a u. a c. k r. r e. k r) * De p t .o fAr c h i t e c t u r a lE n g. ,Gr a d u a t eS c h o o l ,Do n g-E u iUn i v e r s i t y (i c d i e 0 0 @n a v e r. c o m) , * * De p t .o fB u i l d i n gS y s t e m E n g. ,Do n g-E u iUn i v e r s i t y (p y o o l @d e u. a c. k r) , * * * De p t .o fAr c h i t e c t u r a lE n g. ,Do n g-A Un i v e r s i t y (j j y e e @d a u. a c. k r)
Journal of Asian Architecture and Building Engineering, 2002
This paper investigates thermal and ventilation characteristics in a workstation area of an offic... more This paper investigates thermal and ventilation characteristics in a workstation area of an office building equipped with a personal environmental system. An under-floor airconditioning system with and without a desk-mounted PEM (Personal Environmental Module) is compared. A tracer gas experiment using SF6 gas is performed to measure the local supply index and the room mean ventilation effectiveness. The particle image velocimetry is utilized to obtain quantitative velocity vectors in the workstation area for various supply air conditions. As a result, the local supply index in the workstation area is found to be increasing by operating a PEM, while overall room ventilation effectiveness remains the same. Flow visualization results show upward buoyant flows for a heating condition, and there is a need to adjust the angle of the PEM diffuser grille.
Researchers are in continuous search of better strategies to minimize, if not prevent, the anthro... more Researchers are in continuous search of better strategies to minimize, if not prevent, the anthropogenic release of toxic heavy metals, such as Cu(II) and Pb(II), into drinking water resources and the natural environment. Herein, we report for the first time the low-temperature combustion synthesis of magnetic chitosan-manganese ferrite in the absence of toxic cross-linking agents and its removal of Cu(II) and Pb(II) from single-component metal solutions. The nonlinear Langmuir model best described the isotherm data, while the nonlinear pseudo-second order model best described the kinetic data, signifying monolayer Cu(II) or Pb(II) adsorption and chemisorption as the rate-determining step, respectively. Adsorption capacities by magnetic chitosan-manganese ferrite obtained for both metals were consistently higher than those by manganese ferrite, indicating that chitosan enhanced the performance of the magnetic adsorbent. The maximum adsorption capacities of magnetic chitosan-manganes...
The primary purposes of this study are to investigate the feasibility of electrochemical depositi... more The primary purposes of this study are to investigate the feasibility of electrochemical deposition treatment (EDT) as a comprehensive rehabilitation method for corrosion-induced deterioration in reinforced concrete with various severity levels, and to propose a guideline for the determination of critical factors to advance EDT. This study includes three experimental phases, each of which simulates the initiation (de-passivation), propagation (high corrosion activity), and acceleration (formation of a surface-breaking crack) periods of corrosion-induced deterioration. After completion of a series of accelerated corrosion tests, damaged concrete samples with different severity levels are rehabilitated by a series of EDT processes using a MgCl2 solution in an electrolyte. The main variables for this experiment are the concentration levels (0, 0.3, 1.0 and 3.0 M) of a MgCl2 solution for test phase 1, charging time (0, 2, and 7 days) in EDT for test phase 2, and configuration of pre- an...
The main objective of this research is to investigate the effect of water content in concrete on ... more The main objective of this research is to investigate the effect of water content in concrete on the velocities of ultrasonic waves (P- and S-waves) and mechanical properties (elastic modulus and compressive strength) of concrete. For this study, concrete specimens (100 mm × 200 mm cylinders) were fabricated with three different water-to-binder ratios (0.52, 0.35, and 0.26). These cylinders were then submerged in water to be saturated in different degrees from 25% to 100% with an interval of 25% saturation. Another set of cylinders was also oven-dried to represent the dry condition. The dynamic properties of concrete were then assessed using a measurement of elastic wave accordance with ASTM C597-16 and using resonance tests following ASTM C215-19, before and after immersion in water. The static properties of saturated concrete were also assessed by the uniaxial compressive testing according to ASTM C39/C39M-20 and ASTM C469/C469M-14. It was observed that the saturation level of con...
International Journal of Environmental Research and Public Health
This case study covers the application of the fuzzy optimization in simultaneously satisfying var... more This case study covers the application of the fuzzy optimization in simultaneously satisfying various constraints that include the compliance of ammonia and nitrate concentrations with stringent environmental standards. Essential components in the multi-criteria decision-making analysis is in the utilization of the Box-Behnken design (BBD) response equations, cost equations and the cumulative uncertainty of response towards the sodium chloride dosage, current density and electrolysis time parameters. The energy consumption in the electrochemical oxidation of ammonia plays an essential role in influencing the total operating cost analysis. The determination of boundary limits based on the global optimum resulted in the complete ammonia removal and USD 64.0 operating cost as its maximum boundary limits and the 40.6% ammonia removal and USD 17.1 as its minimum boundary limits. Based on the fuzzy optimal results, the overall satisfaction level incurred a decrease in adhering with a lowe...
The widespread presence of heavy metals in drinking water sources arises as a major health concer... more The widespread presence of heavy metals in drinking water sources arises as a major health concern, particularly in developing countries. The development of low-cost and reliable detection techniques is identified as a societal need to provide affordable water quality control. Herein, a bismuth film-coated gold ultramicroelectrode array (BF-UMEA) was used for the detection of Pb(II) and Cd(II) in water samples via square wave anodic stripping voltammetry (SWASV). Experimental parameters such as deposition time, Bi(III) concentration, acetate buffer concentration, pH, square wave frequency, amplitude, and step potential were all varied to determine their effects on the current peak intensities of the target metal ions. Ten-fold excess in the concentration of interferences was found to cause a decrease in the stripping peak areas of Cd(II) and Pb(II) in the following order of magnitude: benzene < NaCl < Ni(II) < Cu(II). Using Box–Behnken design, the optimum SWASV parameters t...
The main objectives of this research are to evaluate the effects of delamination defects on the m... more The main objectives of this research are to evaluate the effects of delamination defects on the measurement of electrical resistivity of reinforced concrete slabs through analytical and experimental studies in the laboratory, and to propose a practical guide for electrical resistivity measurements on concrete with delamination defects. First, a 3D finite element model was developed to simulate the variation of electric potential field in concrete over delamination defects with various depths and lateral sizes. Second, for experimental studies, two reinforced concrete slab specimens (1500 mm (width) by 1500 mm (length) by 300 mm (thickness)) with artificial delamination defects of various dimensions and depths were fabricated. Third, the electrical resistivity of concrete over delamination defects in the numerical simulation models and the two concrete slab specimens were evaluated by using a 4-point Wenner probe in accordance with AASHTO (American Association of State Highway and Tr...
The primary objective of the present work is to measure the corrosion rate of reinforcing steel e... more The primary objective of the present work is to measure the corrosion rate of reinforcing steel embedded in concrete structures in a simulated marine environment of high chloride concentration. The selection of a single frequency that corresponds to the solution resistance and single frequency that corresponds to the charge transfer resistance were performed and measurements were carried out in a relatively faster time. A total of seven cement mortar specimens were prepared. The effect of varying cover thickness (5–50 mm) and rebar distance (10–80 mm) on the electrical resistance of the concrete and corrosion rate of the steel was examined. To simulate the corrosion of reinforced concrete in a marine environment, cement mortars were exposed to 25 wet–dry cycles that involve an immersion for 8 h in 3 wt.% NaCl solution and drying time of 16 h under room temperature. Alternative current (AC) impedance measurements were carried out within a frequency range from 100 kHz to 1 mHz. Results show that the formation of rust layers on rebars has caused a significant decrease in the maximum phase shift to θ = −30°. An accelerated corrosion rate of the rebars was observed during drying stage.
In this paper, the synthesis of a chitosan–montmorillonite nanocomposite material grafted with ac... more In this paper, the synthesis of a chitosan–montmorillonite nanocomposite material grafted with acrylic acid is presented based on its function in a case study analysis. Fuzzy optimization is used for a multi-criteria decision analysis to determine the best desirable swelling capacity (YQ) of the material synthesis at its lowest possible variable cost. For YQ, the integrating the result’s cumulative uncertainty is an essential element to investigate the feasibility of the developed model equation. The Pareto set analysis is able to set the appropriate boundary limits for YQ and the variable cost. Two case studies are presented in determining the lowest possible cost: Case 1 for maximum YQ, and Case 2 for minimum YQ. These boundary limits were used in the fuzzy optimization to determine its global optimum results that achieved the overall satisfaction ratings of 67.2% (Case 1) and 52.3% (Case 2). The synthesis of the polyacrylic acid/chitosan material for Case 1 resulted in 305 g/g YQ...
Journal of Architecture, Planning and Environmental Engineering (Transactions of AIJ)
A novel OPTIMAL sCheme based on the second − order interpolation tecnique is proposed for highly ... more A novel OPTIMAL sCheme based on the second − order interpolation tecnique is proposed for highly accurate and noh ． oscilatory simulation of convection ． The effectiveness of this s (heme is demon − strated through applications of several scalar tra皿 3port problems in twq − dimensiollal lamina エ and l turbulent recirculating flow ． The results are compared to currently avaiable schemes such as PLDS ， QUICK， LODA ， ULTRA − SHARP etc ． ， and the8e result8 demonstrate that the bouhded OPTIMAL and tlie boullded LODA with local full upwinding can give accurate and wiggle free solutions with prQperly designed coarse mesh layout ． Howevel， the OPTIMAL evidently appears advantag θ ous for practical apphcations because of its oomputational simphcity
Bathymetric mapping is traditionally implemented using shipborne single-beam, multi-beam, and sid... more Bathymetric mapping is traditionally implemented using shipborne single-beam, multi-beam, and side-scan sonar sensors. Procuring bathymetric data near coastlines using shipborne sensors is difficult, however, this type of data is important for maritime safety, marine territory management, climate change monitoring, and disaster preparedness. In recent years, the bathymetric light detection and ranging (LiDAR) technique has been tried to get seamless geospatial data from land to submarine topography. This paper evaluated the accuracy of bathymetry generated near coastlines from satellite altimetry-derived gravity anomalies and multi-beam bathymetry using a tuning density contrast of 5000 kg/m3 determined by the gravity-geologic method. Comparing with the predicted bathymetry of using only multi-beam depth data, 78% root mean square error from both multi-beam and airborne bathymetric LiDAR was improved in shallow waters of nearshore coastlines of the western Korea. As a result, the sa...
In the present research, treatment of contaminated groundwater via adsorption of As(V) with an in... more In the present research, treatment of contaminated groundwater via adsorption of As(V) with an initial concentration of 50.99 µg/L using chitosan-coated bentonite (CCB) was investigated. The effect of adsorbent mass (0.001 to 2.0 g), temperature (298 to 328 K), and contact time (1 to 180 min) on the removal efficiency was examined. Adsorption data was evaluated using isotherm models such as Langmuir, Freundlich, and Dubinin-Radushkevich. Isotherm study showed that the Langmuir (R2 > 0.9899; χ2 ≤ 0.91; RMSE ≤ 4.87) model best correlates with the experimental data. Kinetics studies revealed that pseudo-second order equation adequately describes the experimental data (R2 ≥ 0.9951; χ2 ≤ 0.8.33; RMSE ≤ 4.31) where equilibrium was attained after 60 min. Thermodynamics study shows that the As(V) adsorption is non-spontaneous (ΔG0 ≥ 0) and endothermic (ΔH0 = 8.31 J/mol) that would result in an increase in randomness (ΔS0 = 29.10 kJ/mol•K) within the CCB-solution interface. FT-IR analysis...
In the present work, graphene oxide (GO) was synthesized via the modified Hummers method and util... more In the present work, graphene oxide (GO) was synthesized via the modified Hummers method and utilized in treating real soil washing wastewater via adsorptive removal of lead (Pb) and zinc (Zn). Characterization analysis of GO was performed using X-ray diffraction, Brunauer-Emmett-Teller method, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and zeta potential analysis. The Van’t Hoff, Eyring, and Arrhenius equations were applied to determine the activation and thermodynamic parameters namely activation energy (Ea), standard Gibbs energy change (ΔG°), standard enthalpy change (ΔH°), standard entropy change (ΔS°), change in activation Gibbs energy (ΔG#), change in activation enthalpy (ΔH#), and change in activation entropy (ΔS#). Based on the high coefficient of determination values (0.8882 ≥ R2 ≥ 0.9094) and low values of SSE (0.0292 ≤ SSE ≤ 0.0511) and ARE (0.8014 ≤ ARE ≤ 0.8822), equilibrium data agreed well with the Freundlich isotherm. The maximum adsorption capacity for Pb(II) and Zn(II) was determined to be 11.57 and 4.65 mg/g, respectively. Kinetic studies revealed that pseudo-second-order equation fitted well with the experimental data, which indicates that chemisorption is the rate-determining step of the adsorption system. Results have shown the possibility of GO as a potential adsorbent material in the treatment of soil washing wastewater.
In the present work, the performance of spent coffee grounds (SCG) as an adsorbent in the treatme... more In the present work, the performance of spent coffee grounds (SCG) as an adsorbent in the treatment of real soil washing wastewater (SWW) was evaluated. Scanning electron microscopy, Fourier transform infrared spectroscopy, zeta potential measurement and Brunauer–Emmett–Teller analysis were utilized to determine the physicochemical characteristics of SCG. Maximum removal efficiency of 68.73% for Cu(II), 57.23% for Pb(II) and 84.55% for Zn(II) was attained at 2.5 g SCG, 300 min and 328 K. Error analysis was performed using root mean square error (RMSE) and sum of square error (SSE). Equilibrium data correlated well with the Langmuir isotherm for Pb(II) adsorption and Freundlich model for the removal of Cu(II) and Zn(II). The kinetic study shows that adsorption of the heavy metals using SCG can be satisfactorily described using the pseudo-second order equation (R2 ≥ 0.9901; RMSE ≤ 15.0539; SSE ≤ 145.1461). Activation parameters including activation energy, change in free energy of act...
AS t u d yo nt h eE n e r g yC o n s u mp t i o nC h a r a c t e r i s t i cb yBu i l d i n gE n ... more AS t u d yo nt h eE n e r g yC o n s u mp t i o nC h a r a c t e r i s t i cb yBu i l d i n gE n v e l o p eo f Ap a r t me n tHo u s i n gi nBu s a nMe t r o p o l i t a nCi t y 이정재* ․김환용* * †․김승희* * * Y e eJ u r n g-J a e * ,K i m H w a n-Y o n g * * †a n dK i m S e u n g-H e e * * * (S u b mi td a t e:2 0 1 4 .6 .2 3. ,J u d g me n td a t e:2 0 1 4 .6 .2 3. ,P u b l i c a t i o nd e c i d ed a t e:2 0 1 4 .8 .2 5 .
Abstract In this study, an Energy Integrated Support System (EnerISS) Modeler (or simply, Modeler... more Abstract In this study, an Energy Integrated Support System (EnerISS) Modeler (or simply, Modeler), an automated module of a knowledge-based urban planning support system, was developed to support the strategic technology implementation of environmentally friendly local energy planning. Modeler was developed as a tool that integrates various formats of the planning data into a unified format during the planning stage. It automates the three-dimensional (3D) modeling of the integrated urban space and presents visual information to support decision-making processes. The system architecture of Modeler includes the formation of building polygons, textures for classified land cover shape, topography, and 3D urban space. Modeler was developed on a native-based software (S/W) platform. It was created with a single document frame (SDF) from the Windows Microsoft Foundation Class (MFC) Library and is driven by a 3D-based engine that can be used by a GIS client. Modeler was validated for a domestic city in the urban planning stage on a test bed platform. Because of the expansion of a ubiquitous environment and increasing social network services (SNS), the ability to port the Modeler to a web-based platform should be investigated, thus enabling easier access for decision makers.
* 동의대학교 대학원 건축공학과(i c d i e 0 0 @n a v e r. c o m) ,* * 동의대학교 건축설비공학과(p y o o l @d e u. a c. k r)... more * 동의대학교 대학원 건축공학과(i c d i e 0 0 @n a v e r. c o m) ,* * 동의대학교 건축설비공학과(p y o o l @d e u. a c. k r) , * * * 동아대학교 건축공학과(j j y e e @d a u. a c. k r. r e. k r) * De p t .o fAr c h i t e c t u r a lE n g. ,Gr a d u a t eS c h o o l ,Do n g-E u iUn i v e r s i t y (i c d i e 0 0 @n a v e r. c o m) , * * De p t .o fB u i l d i n gS y s t e m E n g. ,Do n g-E u iUn i v e r s i t y (p y o o l @d e u. a c. k r) , * * * De p t .o fAr c h i t e c t u r a lE n g. ,Do n g-A Un i v e r s i t y (j j y e e @d a u. a c. k r)
Journal of Asian Architecture and Building Engineering, 2002
This paper investigates thermal and ventilation characteristics in a workstation area of an offic... more This paper investigates thermal and ventilation characteristics in a workstation area of an office building equipped with a personal environmental system. An under-floor airconditioning system with and without a desk-mounted PEM (Personal Environmental Module) is compared. A tracer gas experiment using SF6 gas is performed to measure the local supply index and the room mean ventilation effectiveness. The particle image velocimetry is utilized to obtain quantitative velocity vectors in the workstation area for various supply air conditions. As a result, the local supply index in the workstation area is found to be increasing by operating a PEM, while overall room ventilation effectiveness remains the same. Flow visualization results show upward buoyant flows for a heating condition, and there is a need to adjust the angle of the PEM diffuser grille.
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Papers by Jurng-jae Yee