• International Journal of Aeronautical and Space Sciences
• /
• v.17 no.3
• /
• pp.341-351
• /
• 2016

In this present work, the effect of hole shapes, orientation and hole arrangements on film cooling effectiveness has been carried out. For this work a flat plate has been considered for the computational model. Computational analysis of film cooling effectiveness using different hole shapes with no streamwise inclination has been carried out. Initially, the model with an inclination of $30^{\circ}$ has been verified with the experimental data. The validation results are well in agreement with the results taken from literature. Five different hole shapes viz. Cylindrical, Elliptic, Triangular, Semi-Cylindrical and Semi-Elliptic have been compared and validated over a wide range of blowing ratios. The blowing ratios ranged from 0.67 to 1.67. Later, orientation of holes have also been varied along with the number of rows and hole arrangements in rows. The performance of film cooling scheme has been given in terms of centerline and laterally averaged adiabatic effectiveness. Semi-elliptic hole utilizes half of the mass flow as in other hole shapes and gives nominal values of effectiveness. The triangular hole geometry shows higher values of effectiveness than other hole geometries. But when compared on the basis of effectiveness and coolant mass consumption, Semi-elliptic hole came out to give best results.

• Korean Management Science Review
• /
• v.12 no.2
• /
• pp.31-42
• /
• 1995

The ordering method is used to reduce the fill-ins in interior point methods. In ordering, the data structure plays an important role. In this paper, first, we compare the efficiency and the memory storage requirement of the quotient graph structure and the clique storage. Next, we propose a method of reducing the number of cliques and a data structure for clique storage. Finally, we apply a method of merging rows and absorbing cliques and show the experimental results.

• Communications of the Korean Institute of Information Scientists and Engineers
• /
• v.5 no.2
• /
• pp.85-89
• /
• 1987

The large sparse matrix problems arise in many applications areas, such as structural analysis, network analysis. In dealing with such sparse systems proper preprogramming techniques such as permuting rows and columns simultaneously, will be needed in order to reduce the number of arithmetic operations and storage spaces.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.6 no.4
• /
• pp.499-504
• /
• 2011

This paper propose the rule of coding for the characters and symbol, etc which are used in computer, information devices, etc. When they use the rule of coding, they may improve the efficiency of transmission in data communications by reducing the number of scrambling during the line coding in the coder in the transmitter. The paper considered the codes of one byte of 3bits column ${\times}$ 4bits rows. ASCII code is one of the representative code for the codes of one byte of 3bits column ${\times}$ 4bits rows. Therefore, this paper applied ASCII code to study the coding rule of the characters and symbols, etc.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.30 no.4
• /
• pp.195-203
• /
• 2018

Mohair is widely used as an airtight material for filling the gap between a window frame and sash. The purpose of this study is to investigate infiltration rate and opening force of sliding windows according to the mohair installation conditions. Infiltration experimental apparatus was set up, and the experimental results were applied to windows to find a correlation between infiltration rates and opening forces. When 4 rows of mohair were installed, the infiltration rate increase became 27.1% per clearance length increase of 1 mm, and the infiltration rate decrease became 5.7% per shortened length increase of 0.1 mm. For 4 rows of mohair, the opening force decreased by 28.2% as the clearance increased by 1 mm, and it increased by 9.3% as the shortened length increased by 0.1 mm.

• Advances in aircraft and spacecraft science
• /
• v.10 no.2
• /
• pp.179-202
• /
• 2023

This article presents a numerical analysis to investigate the natural frequencies and harmonic response of a perforated cantilever beam attached to two layers of piezoelectric materials by using the finite element method for the first time. The bimorph piezoelectric is composed of 3 layers; two of them at the outer are piezoelectric, and the inner isotropic material. A higher order 3-D 20-node solid element that exhibits quadratic displacement behavior is exploited to discretize the isotropic layer, and coupled piezoelectric 3D element with twenty nodes is used to mesh the top and bottom layers. CIRCU94 element is added to act as a resistor part of the model. The proposed model is validated with previous works. The numerical parametric studies are presented to illustrate the effects of perforation geometry, the number of rows, the resistance on the natural frequencies, frequency response, and power. It is found that the thickness has a positive relationship with the natural frequency. Perforations help in producing higher voltage, and the best shape is rectangular perforations, and to produce higher voltage, two rows of rectangular perforations should be applied.

• Journal of Advanced Marine Engineering and Technology
• /
• v.22 no.6
• /
• pp.844-853
• /
• 1998

Natural and forced convection experiments were carried out in order to investigate the effects of channel spacing gap between protrusions and number of rows of protrusion, In natural convection the optimum channel spacing was found to be approximately 20mm regardless of the protrusion gaps. For optimum channel spacing the heat transfer coefficients were converged to an asymptotic value after the fourth row. The heat transfer coefficient for each row approaches to constant values for protrusion gaps larger than 10 mm. An experimental correlation has been suggested by using a modified Rayleigh number based on the dimensionless characteristic length(G/L). In forced convec-tion the heat transfer coefficients were not merged to an asymptote until the fifty row and increases as the channel spacing at the constant Reynolds number decreases.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.49 no.6
• /
• pp.457-462
• /
• 2004

Lodging is one of the most serious problems in soybean cultivation. Therefore, improved cultural methods to reduce lodging as well as to increase photosynthetic ability should be mostly desirable to increase soybean production. The test variety was 'Hwangkeumkong' which was pinched at V7 stage. The greatest difference in canopy height between rows was shown when every other row was pinched, which also recorded the most effective reduction in lodging. The 9th leaf of soybean plants in non-pinching rows of alternative non-pinching and pinching plot showed the highest photosynthetic ability due to the greatest difference in canopy height. Although leaf area index was higher in pinched rows in average after 17 August, alternative pinching of every other row recorded the highest LAI on 5 September. Alternative pinching of every other row resulted $2\~14\%$ higher yield than non-pinching or complete pinching due to the increases of number of grains in the upper part of main stem and average grain weight of non-pinching rows and in alternative pinching.

• ALGAE
• /
• v.39 no.3
• /
• pp.129-147
• /
• 2024

The species complex Mesodinium rubrum / major, common red tide-forming ciliates, has been intensively studied with regards to its ecological roles in global marine ecosystems and the evolutionary aspects of its "stolen" organelles (kleptoplasty and karyoklepty). Nonetheless, the taxonomy of the species within the complex remains unclear. A new marine Mesodinium species isolated from Gomso Bay, Korea, was cultivated under mixotrophic conditions by providing Teleaulax amphioxeia, a red cryptomonad, as prey. Cells of the new isolate consisted of two portions separated by two types of polykinetids. The number of polykinetid associated with the equatorial ciliary belt was approximately 38, and each consisting of two rows of up to 18 alternating kinetosomes each. There was an equal number of cirral polykinetids, each consisting of 16 kinetosomes organized into four longitudinal rows having five, five, four, and two kinetosomes, respectively (in anti-clockwise direction). The two kinds of kinetids and their associated microtubules and fibers were structurally similar to those of M. rubrum from Denmark. However, the Korean Mesodinium species was characterized by its broad posterior portion, 20-22 tentacles, and a cytopharyngeal annulus. Molecular phylogeny based on internal transcribed spacer sequences placed the Korean isolate in clade B of the M. rubrum / major species complex, rather than in clade F representing the neotype of M. rubrum. Based on morphological, ultrastructural, and molecular data, we propose the Korean strain as a new marine Mesodinium species, M. annulatum.

• Parasites, Hosts and Diseases
• /
• v.59 no.5
• /
• pp.519-522
• /
• 2021

The Chinese edible frogs, Hoplobatrachus rugulosus (n=20), and the striped snakehead fish, Channa striata (n=34), were purchased from local markets in 3 administrative regions of Cambodia (Phnom Penh, Pursat, and Takeo Provinces) from May 2017 to April 2019, and their infection status with Gnathostoma sp. larvae was investigated. The frogs and fish were transported to the laboratory with ice and examined using the artificial digestion method. Advanced 3rd-stage larvae (AdL₃) of Gnathostoma spinigerum, 24 in total number (1-6 larvae/frog), were detected from 6 (60.0%) out of 10 frogs purchased from Phnom Penh. No gnathostome larvae were detected in 10 frogs purchased from Takeo Province and 34 snakeheads from Phnom Penh, Pursat, and Takeo Provinces. AdL₃ isolated from the frogs were 2.55-3.90 mm long and 0.31-0.36 mm wide. They had a characteristic head bulb (0.081×0.191 mm in average size) with 4 rows of hooklets, a muscular long esophagus (0.950-1.230 mm long), and 2 pairs of cervical sacs (0.530-0.890 mm long). The average number of hooklets in the 1st, 2nd, 3rd, and 4th rows was 41, 45, 48, and 51, respectively. These features were consistent with G. spinigerum AdL₃. By the present study, it has been first confirmed that the Chinese edible frog, H. rugulosus, from Phnom Penh serves as a second intermediate host for G. spinigerum, although their intensity of infection was not so high compared to other previously reported localities.