• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.11
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• pp.1640-1649
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• 2001

The present study investigates the effects of various rib arrangements on heat/mass transfer in the cooling passage of gas turbine blades. A complex flow structure occurs in the cooling passage with rib turbulators which promote heat transfer on the wall. It is important to increase not only the heat transfer rates but also the uniformity of heat transfer in the cooling passage. A numerical computation is performed using a commercial code to calculate the flow structures and experiments are conducted to measure heat/mass transfer coefficients using a naphthalene sublimation technique. A square channel (50 mm $\times$ 50 mm) with rectangular ribs (4 mm $\times$ 5 mm) is used fur the stationary duct test. The experiments focus on the effects of rib arrangements and gap positions in the discrete ribs on the heat/mass transfer on the duct wall. The rib angle of attack is 60°and the rib-to-rib pitch is 32 mm, that is 8 times of the rib height. With the inclined rib angle of attack (60°), the parallel rib arrangements make a pair of counter rotating secondary flows in the cross section, but the cross rib arrangements make a single large secondary flow including a small secondary vortex. These secondary flow patterns affect significantly the heat/mass transfer on the ribbed wall. The heat/mass transfer in the parallel arrangements is 1.5 ∼2 times higher than that in the cross arrangements. However, the shifted rib arrangements change little the heat/mass transfer from the inline rib arrangements. The gap position in the discrete rib affects significantly the heat/mass transfer because a strong flow acceleration occurs locally through the gap.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.1
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• pp.150-158
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• 2002

Local heat/mass transfer and friction loss in a square duct roughened with various types of continuous and discrete rib turbulators are investigated. The combined effects of the gap flows of the discrete ribs and the secondary flows are examined for the purpose of the reduction of thermally weak regions and the promotion of the uniformity of heat/mass transfer distributions as well as the ;augmentation of average heat/mass transfer. The rib-to-rib pitch to the rib height ratio (p/e) of 8 and the rib angles of 90° and 60° are selected with e/D$\_$h/=0.08. The vortical structure of the secondary flows induced by the parallel angled arrays are quite distinct from that induced by the cross angled arrays. This distinction influences on heat/mass transfer and friction loss in all the tested cases. The gap flows of the discrete ribs reduce the strength of the secondary flows but promote local turbulence and flow mixing. Consequently, the angled discrete ribs with the small gaps provide a more uniform heat/mass transfer distribution sustaining high average heat/mass transfer.

• Journal of Korean Society of Steel Construction
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• v.26 no.4
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• pp.277-288
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• 2014

In this study, the local displacement and moment characteristics of a plate stiffened with closed ribs are analyzed according to the dimensions of stiffened plates. The analyzed results of various stiffened plates under square distributed load show that the effect of the loading panel width to the local behavior is dominant but that of the next panel width is very small. And the local behavior of reference stiffened plates can be expressed by the angle between the plate and the rib, and that of other stiffened plates can be obtained by multiplying ratio functions of the loading panel width, plate thickness, rib thickness, rib height and next panel width and they give good results. Applying ratio functions to other loading sizes shows that the applicability of ratio functions except for the loading panel width is proved and the modified ratio functions of the loading panel width improve error ratios. Therefore, the local displacement and moments of a plate stiffened with closed ribs can easily achieve proper results regardless of the dimensions using ratio functions proposed in this study.

• Korean Journal of Community Nutrition
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• v.11 no.5
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• pp.642-649
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• 2006

The purposes of this study were to investigate methods of applying activity-based cost to menu engineering and to examine the feasibility. A total of 6 menu items of XYZ restaurant in Seoul were selected and the ledger of September 2005 was used for menu analysis. The menu mix percent of beef sirloin steak (61.95%) and beef tenderloin steak (17.13%) were labeled as high, whereas BBQ pork ribs (4.94%), salmon fillet (2.66%), seafood platter (5.77%), and teriyaki chicken (7.56%) showed low menu mix percent. In addition, the contribution margin for BBQ pork ribs (29,000 won), salmon fillet (25,810 won), seafood platter (22,400 won), and teriyaki chicken (22,000 won) were higher than the average contribution margin (21,957 won), and those for beef sirloin steak (21,200 won) and beef tenderloin steak (21,900 won) were lower than average. When popularity and contribution margin were applied in menu engineering, BBQ pork ribs, salmon fillet, seafood platter and teriyaki chicken were classified as puzzles and beef tenderloin steak and beef sirloin steak as plowhorses. Menu engineering using popularity and operating profit, which was calculated from activity-based cost, also gave the same results, whereas the additional label for activity cost placed BBQ pork ribs and salmon fillet in the brain teaser category. Ranking analysis on variables estimating menu profitability using Spear-man's ${\rho}$ revealed that there were no significant correlation between variables, which means the estimation of menu item profitability could differ by methods of analysis. With these results, it was concluded that activity-based cost would help to establish more detailed marketing strategy for a restaurant.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.2
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• pp.176-183
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• 2010

In the steel deck box girder bridges, the deck is composed of deck plate, longitudinal and lateral direction ribs. The bridge, that is considered in this study, has been used for about 40 years and, recently, several cracks were found in the connection area of U-ribs. Further, additional cracks were occurred after some lateral rib plates and longitudinal frames were attached for the purpose of reinforcement. Therefore, the connection method in the U-ribs reinforcement was changed from the bolting to the weldment to get rid of stress concentration and further cracking. In this study, the stress in the U-ribs connection was analysed numerically and variable amplitude stress for the real traffic loads was measured experimentally before and after the frame reinforcement. Finally, the effects of reinforcement method were investigated and discussed.

• Korean Journal of Optics and Photonics
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• v.12 no.2
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• pp.103-108
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• 2001

In this paper, we designed and made the scanned point detecting system for 3-dimensional measurement of the light emitted from plasma display panel (PDP) , and we measured and analyzed 3-dimensional light emitted from a real PDP by using this scanned point detecting system. The scanned point detecting system has a point detector with a pinhole. The light emitted from the source at the in-focus position can pass through the pinhole and be collected by detector. The light from other sources at outof-focus positions is focused at points in front of or behind the pinhole, and thus it is intercepted by the pinhole. Therefore, we can detect light information from a particular point of a PDP cell of 3-dimensional structure. We know the electric field distribution inside the PDP cell from the 3-dimensionallight intensity distribution measured by using the scanned point detecting system. As the Z axial measurement increases, the intensity of light detected increases and intensity of light detected on the inside edge of the ITa electrode is larger than outside edge of the ITa eletrode and gap of the ITa electrodes. Also, as the measurement point moves from one barrier rib to another, the detected light is weaker near to the barrier ribs than at the center between the barrier ribs. The emitted light is concentrated at the center between barrier ribs. ribs.

• Journal of Digital Convergence
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• v.17 no.3
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• pp.119-128
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• 2019

This study examines the effect of Korean Wave recognition on the preference of cheese chicken ribs in Vietnamese students. It also examines the effect of preference of cheese chicken ribs on the Korean food image of Vietnamese students and their intention to visit Korean restaurants. We analyze the results and try to help globalization of Korean food, development of Korean menu and marketing activities. As a result of the analysis, the hypothesis that the recognition of Korean Wave has positive (+) influence on the preference of cheese chicken ribs was not adopted. The recognition of Hallyu influenced the preference of cheese chicken ribs through SNS influence. SNS influence was found to be a mediator between Korean recognition and cheese chicken rib preference. In case of foreigners, they will recognize Korean Wave through various instruments. Based on the results of this study, it is necessary to study various factors that affect the preference of Korean food and the preference of single menu, and to re - examine Korean food which can globalize Korean food.

• Journal of computational fluids engineering
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• v.13 no.4
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• pp.107-113
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• 2008

The present study numerically simulates the flow and heat transfer characteristics of rib-induced secondary flow in a square cooling channel with staggered V-shaped ribs, extruded on both walls. The rib pitch-to-height ratio (p/h) varies from 2.8 to 10 with the rib-height-to-hydraulic diameter ration (h/$D_h$)of 0.07 and the Reynolds number of 50,000. Shear stress transport (SST) turbulence model is used as a turbulence model. Computational results show that complex secondary flow patterns are generated in the channel due to the snaking flow in the streamwise direction for all tested cases. In the range of p/h=5 to 10 the staggered V-shaped rib gives about 3 times higher heat transfer augmentation than the reference smooth pipe with high heat transfer on both front side and the area around the leading edge of the ribs, while the former cases give about 18 times higher streamwise pressure drop than the latter ones. However, for the thermal performances, based on the equal pumping power condition, the case of p/h=2.8 gives the best result among three cases, mainly due to relatively low streamwise pressure drop, although it gives relatively low heat transfer augmentation.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.11
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• pp.1587-1594
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• 2011

Live weight, body length, hip and shoulder heights, heart girth, and metatarsal length were measured on 100 one to two years old Bali (Bos javanicus) bulls. Multiple regression of these measurements on live weight gave a prediction equation involving heart girth and body length (prediction $R^2$ = 0.845). These measurements were also used to derive several frame scores (FS). Live weight (Lwt) divided by FS was used as an index of body condition. Lwt/(length+hip height) was normally distributed and highly correlated with other normally-distributed condition indexes. This index was used to define five body condition scores. These were used to develop a five-point body condition scoring system in which the amount of fleshing over the vertebral processes, ribs, hindquarters, tail head, hooks, at the top of the neck, and the shoulders, the development of wrinkles in the skin above the hock and the neck, and the size of the dewlap, were used to describe the different body condition scores. Animals of score 1 had prominent hooks, shoulders, vertebrae and ribs, and hollow hindquarters and flat tailhead. Score 5 animals had rounded hindquarters, well-filled upper hind legs, small mounds of soft tissue were apparent on the tailhead, their hooks, necks, shoulders, vertebrae and ribs were well covered, and the dewlap was prominent.

• Steel and Composite Structures
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• v.24 no.2
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• pp.249-264
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• 2017

In this paper free linear vibration of lattice composite conical shells will be investigated. Lattice composite conical shell consists of composite helical ribs and thin outer skin. A smeared method is employed to obtain the variable coefficients of stiffness of conical shell. The ribs are modeled as a beam and in addition to the axial loads, endure shear loads and bending moments. Therefore, theoretical formulations are based on first-order shear deformation theory of shell. For verification of the obtained results, comparison is made with those available in open literature. Also, using FEM software the 3D finite element model of composite lattice conical shell is built and analyzed. Comparing results of analytical and numerical analyses show a good agreement between them. Some special cases as variation of geometric parameters of lattice part, effect of the boundary conditions and influence of the circumferential wave numbers on the natural frequencies of the conical shell are studied. It is concluded, when mass and the geometrical ratio of the composite lattice conical shell do not change, increment the semi vertex angle of cone leads to increase the natural frequencies. Moreover for shell thicknesses greater than a specific value, the presence of the lattice structure has not significant effect on the natural frequencies. The obtained results have novelty and can be used for further and future researches.