• 한국물환경학회지
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• 제32권4호
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• pp.375-383
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• 2016

Total Pollution Load Control (TPLC) calculates and manages the allowable pollutant load that is discharged from the watershed, which can meet the water quality target. Delivery Ratio (DR) is generally used for predicting the variation of pollutant mass balance between the pollutants discharged from the watershed and a certain point in the stream, and it is very important for estimation of accurate allowable pollutant load. The concept of DR in TPLC is different from prevalent DR, because DR in TPLC includes both the discharge of pollutants from the watershed and the delivery mechanism. Therefore, DR in TPLC should be estimated by using a proper and unified methodology. The appropriate method and equation for estimation of DR in TPLC was developed through the review of various methodologies, and the applicability of the equation was evaluated in a study area (Geumho A). Determination coefficients (R²) of regression were shown to be relatively high (BOD 0.71~0.87, T-N 0.86~0.90, T-P 0.62~0.69). Applicability of the developed methodology and equations was evaluated as appropriate for TPLC, and it is suggested.

• 한국수산과학회지
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• 제56권4호
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• pp.473-483
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• 2023

This study was conducted to better understand the impact of marine fish farming by estimating mass balances of carbon and nitrogen. According to the results, 94.55% of carbon and 95.66% of nitrogen inputs were from the feed supplied in the farm. Of the total carbon emissions in the farm, 47.28% was due to fish respiration, which was subsequently released into seawater. Advection and diffusion in the farm contributed to 30.29% of the carbon released. In the case of nitrogen, 50.70% of the nitrogen released into the seawater was produced by fish excreta, and 31.37% was advected and diffused into the system. The sedimentary environment received 3.82% and 3.10% of the carbon and nitrogen released from the farm, respectively. The fish feed used for healthy growth contained 11.64% carbon and 9.17% nitrogen. Since the feed type was floating pellets, the load released into the sedimentary environment was relatively lower than that released into the marine environment. These findings suggest that the identification of an optimal fish feed that respects fish physiology and preserves a healthy ecology is critical for the future of aquaculture. Furthermore, ecosystem-based aquaculture systems that decrease environmental burden, while endeavoring to improve environmental health, are required.

• 한국물환경학회지
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• 제27권1호
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• pp.19-29
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• 2011

In order to assess the influences of bottom sediment on water quality, following measurement were made. (1) Estimations of pollutant loads from the bottom sediment based on mass balance concept, (2) measurements of pollutant concentrations in the sediment to assess the pollution level and influence potential, (3) in situ and laboratory measurements of Sediment Oxygen Demants (SOD) and pollutant load (sediment release) from bottom sediment. Analyses of inflow and outflow loadings using simple mass balance show that there are some variations found according to the pollutants. However, there is no consistent evidence that the sediment can be a source of pollutants. Pollutant concentrations in the sediment range 16~724.8 mg/kg (COD), 1.68 ~12.64 mg/kg (T-P), 5.6~76.8 mg/kg (T-N), 0.32~21.6 mg/kg ($NH_3$-N), 0.092~0.544 mg/kg ($NO_2$-N), 4.8~18.4 mg/kg ($NO_3$-N), and 1.59~11.23 mg/kg ($PO_4$-P). Measured SOD ranges $0.190{\sim}0.802g{\cdot}m^{-2}{\cdot}d^{-1}$ and measured release rate ranges $-1618.42{\sim}10mg/m^2{\cdot}d$(COD), $-12{\sim}16mg/m^2{\cdot}d$(T-P), $-197.37{\sim}140mg/m^2{\cdot}d$(T-N), $0.4{\sim}74.32mg/m^2{\cdot}d$($NH_3$-N), $-2.04{\sim}0.8mg/m^2{\cdot}d$ ($NO_2$-N), $-70{\sim}40mg/m^2{\cdot}d$ ($NO_3$-N), and $-26.11{\sim}28.55mg/m^2{\cdot}d$($PO_4$-P). All study results indicate that bottom sediments in the Seoha weir show only limited effects on the water quality. It implies that sediment dredging is not an effective option or management measure to reduce pollutant loading.

• 한국물환경학회지
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• 제32권6호
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• pp.589-599
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• 2016

Implemented since 2004, TPLC (Total Pollution Load Control) is the most powerful water-quality protection program. Recently, uncertainty of prediction using steady state model increased due to changing water environments, and necessity of a dynamic state model, especially the watershed model, gained importance. For application of watershed model on TPLC, it needs to be feasible to adjust the relationship (mass-balance) between discharged loads estimated by technical guidance, and arrived loads based on observed data at the watershed outlet. However, at HSPF, simulation is performed as a semi-distributed model (lumped model) in a sub-basin. Therefore, if the estimated discharged loads from individual pollution source is directly entered as the point source data into the RCHRES module (without delivery ratio), the pollutant load is not reduced properly until it reaches the outlet of the sub-basin. The hypothetic RCHRES generated using the HSPF BMP Reach Toolkit was applied to solve this problem (although this is not the original application of Reach Toolkit). It was observed that the impact of discharged load according to spatial distribution of pollution sources in a sub-basin, could be expressed by multi-segmentation of the hypothetical RCHRES. Thus, the discharged pollutant load could be adjusted easily by modification of the infiltration rate or characteristics of flow control devices.

• Asian-Australasian Journal of Animal Sciences
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• 제13권5호
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• pp.605-612
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• 2000

Four young swamp buffalo cows of similar age ranging in weight between 280 to 380 kg and trained to do physical work were used in a study to determine energy and protein requirements for draught using a $4{\times}4$ Latin square designed experiment. The experiment consisted of field trials employing 4 levels of work load, e.g. no work as control, and loads amounting 450 to 500 Newton (N) pulled continuously for 1, 2 and 3 h daily for 14 consecutive days. Cows were fed king grass (Penisetum purpuroides) ad libitum and were subjected to materials balance trials. Body composition was estimated in vivo by the body density method and daily energy expenditure (EE) was calculated from ME minus retained energy (RE). The results show that EE while not working ($EE_{resting}$) was $0.42kgW^{0.75}MJ/d$ and maintenance ME ($ME_m$) was $0.37kgW^{0.75}MJ/d$. ME requirement increased to 1.65 times maintenance for the work of 3 hours. The energy expended for doing exercise ($E_{exercise}$) was 9.56, 20.0 and 25.86 MJ/cow for treatments 1, 2 and 3 II, respectively. Fat retention was absent in all groups of working cows, but protein retention was only negative for cows undertaking 3 h work. The relationship between $E_{exercise}$ (MJ), work load (F, kN), work duration (t, h) and body mass (W, kg) was found to be: $E_{exercise}=(0.003F^{1.43}t^{0.93})/W^{0.09}MJ$. The maintenance requirement for digestible protein was $2.51kgW^{0.75}g/d$, whereas digestible protein for growth ($DP_{growth}$) and for work ($DP_{work}$) followed the equations: $DP_{growth}=[(258+1.25W^{0.75}){\Delta}Wkg/d]g$ and $DP_{work}=[12.59e^{0.95t}]g$, respectively The coefficients a, b and c for the calculation of $E_{exercise}$ components according to the Lawrence equation were found to be 2.56 J/kgW.m, 5.2 J/kg load carried.m and 0.29, respectively, thus efficiencies to convert ME into work were 0, 16.09, 27.3 and 32.44% for control, 1, 2 and 3 h/d work, respectively. ME and DP requirements for a 250 to 400 kg working buffalo cow allowing to growth up to 0.5 kg/d are presented.

• 환경영향평가
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• 제21권5호
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• pp.725-734
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• 2012

The outbreak of foot and mouth disease in November 2010 raised many social, economic and environmental issues and water contaminations by leachate from carcass disposal sites particularly emerged as a serious concern. In oder to efficiently handle these problems, a critical method is required to transport leachate to livestock manure and sewage treatment plants and purify it. This study aims to present the best applicable method to transport leachate from carcass disposal sites into livestock manure and sewage treatment facilities. We investigated the biological and chemical characteristics such as BOD, COD, SS, TN, TP and Total coliforms. Current conjugated treatments in livestock manure and sewage treatment plants was studied by surveying the operations of those facilities. The NIER-MASS(National Institute of Environmental Research - Mass Balance Evaluation System of Sewage Treatment Facilities) program was applied to present the best conjugated treatment method through estimating the maximum daily load to meet the water quality standards in effluent.

• 한국연소학회지
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• 제23권1호
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• pp.44-54
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• 2018

Heat and mass balance process modeling has been conducted for a coal-firing power plant to be used as a testbed facility for development of various plant systems and equipment. As the material and design of the boiler tube bundle and fuel conversion to the biomass have become major concerns, the process modeling is required to incorporate those features in its calculation. The simulation cases for two different generation load show the satisfying results compared to the operational data from the actual system. Based on the established process conditions, the hypothetical case using wood pellet has also been simulated. Additional calculations for the tube bundle has been conducted regarding the changes in the tube material and design.

• 설비공학논문집
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• 제14권4호
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• pp.304-314
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• 2002

Performance analysis of the automotive air-conditioning system is conducted by using computer simulation, and performance tests are carried out by using the climate wind tunnel in order to verify simulation. Evaporator and condenser were modeled by using empirical correlation which was obtained from calorimeter data, and compressor was modeled by using map based method. The steady state thermodynamic conditions of refrigerant satisfying mass and energy balance were assumed in the simulation program for automotive airconditioning system. The system performance was analyzed by finite difference method until differential air enthalpy between evaporator inlet and outlet becomes converged. Simulation results are in good agreement with experimental results at most operating conditions. Variation of discharge temperature and pressure of compressor, outlet temperature of evaporator, cooling capacity, and COP were investigated in term of air volume flow rate for evaporator, compressor capacity, compressor speed, superheat of thermostatic expansion valve, and diameter of suction line.

• Tribology and Lubricants
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• 제35권6호
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• pp.369-375
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• 2019

This paper presents a new method on how to calculate the thrust forces acting on an auto-leveling device in headlamps for passenger vehicles. The leveling device is used to lower the angle of lights when a load in the trunk of the vehicle lifts it. In the process of the headlamp design, it is imperative to predict the external forces so that the designers can decide whether to proceed or not. The device is composed of three pivot joints with no reaction moment, a plate that holds the lamp, and a leveling motor that changes rotation to linear motion. In this study, force balance, moment balance, and geometric compatibility are applied to the leveling device system so that a nonlinear system of equations can be derived; the multi-dimensional Newton-Raphson algorithm is then used to solve these. A sensitivity analysis is carried out to verify which design variables affect the system the most: the mass of the lamp and the height between the pivot and leveling device affect the thrust forces the most. Then, considering the friction forces between the moving parts, the hysteresis of the forces are derived. An experimental apparatus, designed and developed in this study, is used to verify the exactness of the derived equations. The results from experiments coincide well with the calculated results. The friction hysteresis, in particular, proves this upon analysis.

• International Journal of Aeronautical and Space Sciences
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• 제17권1호
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• pp.29-36
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• 2016

Tensairity girder is a light weight inflatable fabric structural concept which can be used in road emergency transportation. It uses low pressure air to stabilize compression elements against buckling. With the purpose of obtaining the comprehensive target of minimum deflection and weight under ultimate load, the cross-section and the inner pressure of tensairity girder was optimized in this paper. The Variable Complexity Modeling (VCM) method was used in this paper combining the Kriging approximate method with the Finite Element Analysis (FEA) method, which was implemented by ABAQUS. In the Kriging method, the sample points of the surrogate model were outlined by Design of Experiment (DOE) technique based on Optimal Latin Hypercube. The optimization framework was constructed in iSIGHT with a global optimization method, Multi-Island Genetic Algorithm (MIGA), followed by a local optimization method, Sequential Quadratic Program (SQP). The result of the optimization gives a prominent conceptual design of the tensairity girder, which approves the solution architecture of VCM is feasible and efficient. Furthermore, a useful trend of sensitivity between optimization variables and responses was performed to guide future design. It was proved that the inner pressure is the key parameter to balance the maximum Von Mises stress and deflection on tensairity girder, and the parameters of cross section impact the mass of tensairity girder obviously.