• Journal of Appropriate Technology
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• v.5 no.1
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• pp.8-17
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• 2019

Solar pumps, for water lift systems, is becoming popular in rural areas for supplying drinking water in dry seasons when its need is elevated. The development in technology has also made solar pumps readily available and cheap which has increased its demands. So, for scattered settlements having a limited budget for operation and maintenance costs, solar pump is preferred over grid connected electrical pumping systems. This primary objective of the study was to design a solar photovoltaic pumping drinking water supply system for a small health post which is about 45 km east from Kathmandu, the capital city of Nepal. The study also compared and verified the final design with the system's existing design prepared by a development agency. The water source for this study was a confined aquifer 115m below the surface. The water demand was calculated to be 11m³ per day. A 1500 kPa submersible pump attached to a motor was selected and installed. Along with that twelve solar panels, reservoir, transmission main and distribution main was designed. The outcomes conclude solar photovoltaic pumping water supply systems to be cost-effective with an estimated cost of only USD 0.84 million per MLD. Solar pumps require low maintenance and operation costs and its repairs can quickly be done by the local people. The study also shows that solar technology produces no sound, needs no fuel making it environmentally friendly.

• Geomechanics and Engineering
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• v.15 no.1
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• pp.687-694
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• 2018

To investigate the crushing behaviour of coarse granular materials, a specifically designed, large-scale simple shear apparatus with eight-staged shearing rings was developed. A series of monotonic simple shear tests were conducted on two kinds of coarse granular materials under different vertical stresses and large shear strains. The evolution of the particle breakage during the compression and simple shearing processes was investigated. The results show that the amount of particle breakage is related to the particle hardness and the state of the stresses. The amount of particle breakage is greater for softer granular materials and increases with increasing vertical stresses. Particle breakage may tend towards a critical value during both the compression and the shearing processes. Particle breakage mainly occurs during the processes of confined compression and contraction.

• International Journal of Fluid Machinery and Systems
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• v.9 no.4
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• pp.382-393
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• 2016

Flow over a bluff body is an attractive research field in thermal engineering. In the present study, laminar flow over a confined heated square cylinder using CuO-Water nanofluid is considered. Unsteady two-dimensional Navier-Stokes and energy equations are solved numerically using finite volume method (FVM). Recent correlations for the thermal conductivity and viscosity of nanofluids, which are function of nanoparticle volume fraction, temperature and nanoparticle diameter, have been employed. The results of numerical solution are obtained for Richardson number, nanoparticle volume fractions and nanoparticle diameters ranges of 0-1, 1-5% and 30-100 nm respectively for a fixed Reynolds number of Re = 150. At a given volume concentration, the investigations reveal that the decreasing in size of nanoparticles produces an increase in heat transfer rates from the square cylinder and a decrease in amplitude of the lift coefficient. Also, the increment of Nusselt number is more pronounced at higher concentrations and higher Richardson numbers.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.40-47
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• 2012

Hydrologic responses to the 4September 2010 $M_W$ 7.1 and 22 February 2011 $M_W$ 6.2 Canterbury earthquakes ranged from near instantaneous co-seismic liquefaction and changes in groundwater levels, to more sustained (days to months) changes in river discharge, spring flow and groundwater level. There was some indication of a sustained change in aquifer properties. This paper presents some of the hydrographs from the September and February events, and compares the response to each event, briefly taking into account the location of the bore relative to each earthquake, together with other factors such as borehole depth. Over the months following the September earthquake, a pattern emerged of relatively short-term responses in the shallow aquifers and in the confined aquifer system, close to the coast. A longer term response appears to have occurred in inland, deep bores, where water levels 12 months after the September event were (in some cases) up to 20 metres higher than would have been expected based on simple modelling (see Figure 3). Some examples of these are highlighted.

• Applied Science and Convergence Technology
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• v.27 no.4
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• pp.75-77
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• 2018

The electrostatic interaction between emerging quantum-confined nanostructures with plasmonic structures is crucial for future biological applications. Water-soluble green fluorescent copper nanoparticles (Cu-NPs) were fabricated. We demonstrate that L-ascorbic acid is considered as a key to precisely control small Cu-NPs and the capability of the surface ligands, while cetyltrimethylammonium bromide is used as a stabilizing agent controls the particle growth, and stabilizes the nanoparticles. Water-soluble green fluorescent Cu-NPs are tunable through modification of the reaction periods.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.57-62
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• 2001

Korea Atomic Energy Research Institute (KAERI) launched an intermediate scale steam explosion experiment named Test for Real cOrium Interaction with water (TROI) using reactor material to investigate whether the corium would lead to energetic steam explosion when interacted with cold water at low pressure. The melt-water interaction is confined in a pressure vessel with the multi-dimensional fuel and water pool geometry. The cold crucible technology, where the mixture of powder in a water-cooled cage is heated by high frequency induction, is employed. In this paper, results of the first series of tests ($TROI-1{\sim}5$) were discussed. The ZrO2 jets with 5kg mass and 5cm diameter were poured into the 67cm deep water pool at $30{\sim}95^{\circ}C$. Either spontaneous steam explosions or quenching was observed. The morphology of debris and pressure wave profiles clearly indicates the each case.

• Journal of the Korea Concrete Institute
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• v.23 no.1
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• pp.99-107
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• 2011

This study is to performed to find the optimum mix proportion of the high strength and self compacting concrete for the above-ground LNG storage tank construction and field application. If LNG storage tank wall thicknesscan be reduced, the construction cost and quality can be improved by using self-compacting high strength concrete with compressive strength 60~80 MPa. For this purpose, low heat cement (Type IV) and class F fly ash are used in concrete mix to control hydration heat, flowability, and viscosity. Mix design variables of unit water, fly ash replacement ratio, water-binder ratio, and fine aggregate ratio are selected and tested for material properties and manufacturing cost of the concrete. Also, fly ash replacement ratio is considered using confined water ratio test. The test results showed that the optimum mix proportion of the self-compacting high strength concrete characteristics are as follows. 1) In case of the concrete with specified compressive strength of 60 MPa, the optimum mix proportion is fly ash replacement ratio of 20% and water- binder ratio of 27~30%. 2) In case of the concrete with the strength of 80 MPa, the optimum mix proportion is fly ash replacement ratio of 10% and water-binder ratio 25%. But unit water and fine aggregate ratio are 165 $kg/m^3$ and $51{\pm}2%$, respectively, regardless of the traget concrete compressive strength range. Also, test results showed that concrete manufacturing cost of 60 MPa and 80 MPa concrete require additional costs of 14~22% and 33%, respectively, compared to the manufacturing cost of 40 MPa concrete. Therefore, application of the self-compacting high strength concrete has proven to be economical in the perspective of the material cost, quality control, and site management.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.6 s.237
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• pp.653-661
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• 2005

The present study numerically investigates two-dimensional fluid flow and heat transfer ir the confined jet flow in the presence of applied magnetic field. For the purpose of controlling vortex shedding and heat transfer, numerical simulations to calculate the fluid flow and heat transfer in the confined jet are performed for different Reynolds numbers in the absence and presence of magnetic fields and for different Prandtl numbers of 0.02 (liquid metal), 0.7 (air) and 7 (water) in the range of $0{\le}N{\le}0.05$, where N is the Stuart number (interaction parameter) which is the ratio of electromagnetic force to inertia force. The present study reports the detailed information of flow and thermal quantities in the channel at different Stuart numbers. As the intensity of applied magnetic fields increases, the vortex shedding formed in the channel becomes weaker and the oscillating amplitude of impinging jet decreases. The flow and thermal fields become the steady state if the Stuart number is greater than the critical value. Thus the Nusselt number at the stagnation point representing the heat transfer characteristics also vary as a function of Stuart number.

• Journal of environmental and Sanitary engineering
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• v.20 no.2 s.56
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• pp.47-55
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• 2005

The World Health Organization(WHO, 1998) and the United States Environmental Protection Agency (USEPA, 1992) recommended $2{\mu}\;guranium/{\ell}$ in drinking water as a guideline. The Korea Institute for Environmental Research recently reported that the radioactive pollution in ground water was almost negligible In Korea$(1999\~2002)$. Cs were cast into beads(2mm in wet form) and treated with hexamethylene diisocyanate for stability in acidic aqueous solution through cross-linking of the beads surfaces. The removal study was carried out in a static batch system and a flow system. In the static system, a certain amount of sample water was confined in a vessel and beads(dry weight 0.5g) were packed into it in order to adsorb uranium for a certain period of time. Afterwards the remaining uranium in water vessel was determined by inductively coupled plasma mass spectrometry. The effective pH range was 4 to 8. The smaller the size of beads, the better the removal efficiency. Furthemore, the lower the flow rates, the higher the removal efficiency. The results showed that chitosan beads can be effectively used for the removal of uranium contained in water.

• The Journal of Engineering Geology
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• v.13 no.1
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• pp.67-82
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• 2003

Pumping test data obtained from five natural mineral-water producing companies (Siwon Saemmul, Daejeong Eumryo, Jain Guanguang, Cheongsu Eumryo and Hanju Sikpum) that are located within 1 km radius around Mockcheon area were analyzed. Theis(1935), Papadopulos-Cooper(1967), Hantush(1960, 1962), Hantush-Jacob(1955), Moench(1985), Neuman-Witherspoon(1969), Gringarten-Witherspoon(1969) and Gringarten-Ramey(1974) equations were applied to the pumping test analysis. The result of the pumping test analysis shows that wedge-typed confined aquifer model (Hantush, 1962) and leaky confined aquifer Case-1 model (Moench, 1985) were suitable for the study area. The models match well with geologic structure in the study area which controls aquifer by means of two major thrust faults having Nl8E and NS strikes, respectively.