• Journal of Korea Water Resources Association
• /
• v.38 no.4 s.153
• /
• pp.313-321
• /
• 2005

The elimination and erosion of cohesive sediments in port and reservoir water can so far be processed only with mechanical evacuation methods under extreme energy expenditure. The so-called flushing jets do not serve the purpose because they cannot set the material spaciously in motion despite high shear stresses at the bed. Therefore this study aims to examine the resuspension of the deposited fine material($Al_{2}O_3$) under presence of gas bubbles in order to decreased cohesive sediments in multipurpose dam, port and lakes. In the case of laboratory trial important parameters considered are supplied amount of air and the consolidation time of the solid materials. With increasing gas content alumina remains in suspension at high pH values in the laboratory test, where the particles fall mote rapidly without air addition.

• Korean Chemical Engineering Research
• /
• v.54 no.4
• /
• pp.543-547
• /
• 2016

Bubble properties such as size (chord length) and rising velocity were investigated in a bubble column with electrolyte solutions, of which diameter was 0.152m and 2.5m in height, respectively. The size and rising velocity of bubbles were measured by using the dual electrical resistivity probe method. Effects of gas and liquid velocities and ionic strength of liquid phase on the size and rising velocity of bubbles were determined. The bubble size increased with increasing gas velocity but decreased with increasing liquid velocity or ionic strength of liquid phase. The rising velocity of bubbles increased with increasing gas velocity and decreased with increasing ionic strength of liquid phase, however, it showed a slight maximum value with varying liquid velocity. The size and rising velocity of bubbles were well correlated with operating variables.

• Journal of the Korean Society of Industry Convergence
• /
• v.24 no.6_2
• /
• pp.763-772
• /
• 2021

Drilling Mud Treatment Systems are widely used for Oil Gas drilling mud circulation, horizontal directional drilling mud recycling, geothermal drilling, mining, coal exploration drilling, water well drilling. Degasser is a device used in drilling to remove gasses from drilling fluid which could otherwise form bubbles. For small amounts of entrained gas in a drilling fluid, the degasser can play a major role of removing small bubbles that a liquid film has enveloped and entrapped. As with the desander, its purpose is to remove unwanted solids from the mud system. The smaller cones allow the desilter to efficiently remove smaller diameter drill solids. In this study, a simulation study is conducted on the degasser of the facility in the Mud Treatment System to conduct a performance review on the gas separation in the mud.

• Analytical Science and Technology
• /
• v.6 no.2
• /
• pp.1071-1080
• /
• 1993

• Geotechnical Engineering
• /
• v.5 no.4
• /
• pp.47-60
• /
• 1989

Soft offshore sediments quite frequently contain undissolved gas, probably methane pro- duced biogenically. The presence of gas bubbles can have a significant effect on the engineering behaviours of the seabed. One of the main difference between saturated and gassy soils is that the undrained response is not incompressible, and without volume change, may be assumed for a fully saturated soil. This paper describes the basic experimental work to further understanding of a gassy soil. The test has been performed for a gassy soil under undrained and drained conditions. It was confirmed that the gas inclusions deformed due to changes in the total stress on the sample and also the pore gas pressure response to change in total stress. but not directly to those in pore water pressure. And the test which applied the repeated load under undrained state also showed the similar behaviour as the simple load.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.21 no.7
• /
• pp.77-83
• /
• 2022

When carbon dioxide in a liquid becomes supersaturated, carbon dioxide gas bubbles are generated in the liquid, and they ascend to the surface as they develop further. At this time, the inner wall of the cup with carbon gas attached is known as the entrapped gas cavity (EGS); once an EGS is established, it does not disappear and will continuously create carbon bubbles. This bubbling phenomenon can be activated or suppressed by changing the properties of the solid surface in contact with the carbonated liquid. In this study, the foaming of carbonated liquid is promoted or suppressed by modifying the wettability of the surface. A micro/nano surface structure is formed on the surface of an aluminum cup to produce a superhydrophilic surface, and a superhydrophobic surface similar to a lotus leaf is synthesized via fluorination. Experiment results show that the amount of carbon dioxide bubble generated differs significantly in the first few seconds depending on the surface, and that the amount of gas generated after it enters the stabilization period is the same regardless of the wettability of the cup surface.

• Fisheries and Aquatic Sciences
• /
• v.25 no.1
• /
• pp.40-48
• /
• 2022

Seahorses, which have been cultivated since the 2000s, are economically very important. Gas bubble disease (GBD) is a significant concern in the cultivation of seahorses; therefore, this study aimed to determine the cause of GBD-induced death in two species of Syngnathidae (Syngnathus schlegeli and Hippocampus haema). Rod-shaped bacteria were observed histopathologically and identified as Vibrio splendidus by conventional and real-time PCR analyses. The lethality of V. splendidus varies depending on the host's immune status, and the disease can be prevented through water quality management or improvement of the breeding environment. In this study, the GBD lesions (gas bubbles) were observed at 12℃, 8.0 mg/L of dissolved oxygen, 30 ppt of salinity, and pH 7.7. In addition, rod-shaped bacteria, infiltration of inflammatory cells, and extensive serous exudate were confirmed in the lesions where gas bubbles were found. PCR analysis was able to detect V. splendidus, possibly a secondary infection of the immunocompromised syngnathid fish. Understanding the risk of immunity control and the correlation between these lesions and causal agents will be of great help to the aquaculture industry and the ornamental fish market.

• Journal of The Korean Astronomical Society
• /
• v.51 no.6
• /
• pp.185-195
• /
• 2018

Galaxy clusters are known to host many active galaxies (AGNs) with radio jets, which could expand to form radio bubbles with relativistic electrons in the intracluster medium (ICM). It has been suggested that fossil relativistic electrons contained in remnant bubbles from extinct radio galaxies can be re-accelerated to radio-emitting energies by merger-driven shocks via diffusive shock acceleration (DSA), leading to the birth of radio relics detected in clusters. In this study we assume that such bubble consist primarily of thermal gas entrained from the surrounding medium and dynamically-insignificant amounts of relativistic electrons. We also consider several realistic models for magnetic fields in the cluster outskirts, including the ICM field that scales with the gas density as $B_{ICM}{\infty}n^{0.5}_{ICM}$. Then we perform time-dependent DSA simulations of a spherical shock that runs into a lower-density but higher-temperature bubble with the ratio $n_b/n_{ICM}{\approx}T_{ICM}/T_b{\approx}0.5$. We find that inside the bubble the shock speed increases by about 20 %, but the Mach number decreases by about 15% in the case under consideration. In this re-acceleration model, the observed properties of a radio relic such as radio flux, spectral index, and integrated spectrum would be governed mainly by the presence of seed relativistic electrons and the magnetic field profile as well as shock dynamics. Thus it is crucial to understand how fossil electrons are deposited by AGNs in the ICM and how the downstream magnetic field evolves behind the shock in detailed modeling of radio relics.

• Journal of Environmental Science International
• /
• v.26 no.6
• /
• pp.711-717
• /
• 2017

Dielectric Barrier Discharge (DBD) plasma is a new technique for use in environmental pollutant degradation, which is characterized by the production of hydroxyl radicals as the primary degradation species. Due to the short lifetime of the chemically active species generated during the plasma reaction, the dissolution of the plasma gas has a significant effect on the reaction performance. The plasma reaction performance can be enhanced by combining the basic plasma reactor with a homogenizer system in which the bubbles are destroyed and turned into micro-bubbles. For this purpose, the improvement of the dissolution of plasma gas was evaluated by measuring the RNO (N-dimethyl-4-nitrosoaniline, an indicator of the generation of OH radicals). Experiments were conducted to evaluate the effects of the diameter, rotation speed, and height of the homogenizer, pore size, and number of the diffuser and the applied voltage on the plasma reaction. The results showed that the RNO removal efficiency of the plasma reactor combined with a homogenizer is two times higher than that of the conventional one. The optimum rotor size and rotation speed of the homogenizer were 15.1 mm, and 19,700 rpm, respectively. Except for the lowest pore size distribution of $10-16{\mu}m$, the pore size of the diffuser showed little effect on RNO removal.

• Korean Journal of Food Science and Technology
• /
• v.26 no.3
• /
• pp.195-198
• /
• 1994

A bubble counter was designed and fabricated for the measurement of gas production rate on the basis of number of bubbles produced from yeast fermentor. The sensor was consisted of bubble forming device and electronic signal processing circuitry. The bubble forming device was built with bubble collector and liquid cell to form uniform size of bubble. Bubbles were counted by pulses formed by photo-interrupter circuitry having 8-bit binary latch counter. The gas production rate curves on the basis of bubble counted showed a good agreement to that of growth curves obtained by the optical measurement method. The sensor was succesfully applied to monitoring of the nutrient utilization test with glucose and galactose media.