• Aerospace Engineering and Technology
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• v.4 no.1
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• pp.143-149
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• 2005

To evaluate the hydraulic and cavitation performance of a fuel pump for a liquid rocket engine, performance tests of the pump, which consist of hydraulic tests and cavitation tests, were conducted in water environment with various condition. In the hydraulic tests, the head, efficiency and volute pressure distribution of the pump are found to follow the conventional similarity rule, whereas the secondary flow pressure shows a small deviation from the similarity rule. As the floating gap is constricted, the efficiency of the pump improves and the secondary flow pressure decreases. However, the inner diameter of bypass line orifice does not show clear relationship with the pump efficiency. In the cavitation tests, measurements of the head and the NPSH indicate that the pump shows better cavitation performance as the rotational speed of the pump increases.

• Korean Journal of Head & Neck Oncology
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• v.22 no.1
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• pp.43-46
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• 2006

Granular cell tumor is not rare and is a well recognized entity which has a wide anatomic distribution, with roughly one half of the lesions found in the head and neck. However, occurrence in the thyroid is extremely rare and has not been described well as surgeon's view. The authors have recently experienced a case of multifocal granular cell tumor of the thyroid in a 26-year-old women presented with painless mass in the anterior neck area and fatigue. So, we present this case with the review of literatures.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1487-1494
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• 1990

In this paper the dynamic characteristics of self acting air lubricated slider bearing of hard disk/head system are investigated. The dynamic equations of magnetic head mechanism considering both parallel and pitch motion and the time dependent modified Reynolds equation are analyzed and the dynamic pressure distribution of air film is numerically calculated in frequency domain by small perturbation method and finite difference scheme with variable grid. The dynamic response of the slider spacing is obtained accordingly as the moving recording surface vibrates in parallel mode.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.12
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• pp.1045-1050
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• 2014

A Head-Up-Display is an avionic equipment to identify targets and flight data at same time the pilot looks over the external environment outside canopy. The HUD displays various symbols to depend on avionic mode which is composed of navigation mode, air-to-air mode, air-to-ground mode. In air-to-air mode, HUD should provide the intuitive symbols for pilot to aim the target exactly in a short time. In this paper, we propose a design method to improve the visibility of the HUD Symbols.

• Fashion & Textile Research Journal
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• v.1 no.3
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• pp.246-251
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• 1999

Headdress which adorns the head has been used not only as a type of dress but also as a vehicle to express the human's mentality and a tool to convey ideas. This study first examines the type of headdress observed in the world folk costumes and investigates their geographical distribution and aims to examine how the types of headdress are inter-related to the peoples' natural environments, way of life and cultural background such as religion and aesthetic, ethical standards. Headdress used as important elements of many peoples' folk costumes can be categorized into scarf-type, hat-type and adornment-type. Veil-type, the one of scarf-types, was developed in Southwestern Asia and Arabic Africa influenced by natural and religious factors. This type is more simplified in Turkey and Eastern Europe and only covers head and neck in the former and only head in the latter while also being called 'headkerchief-type'. Hat-type is observed in many different parts of the world. Adornment-type has been used to symbolized one's noble social status and authority in societies dominated by shamanistic cultural background; it was also used in Far East out of the motivation to fulfil one's aesthetic desire. Headdress though it was originally made from the idential purpose of wearing, has developed into the various types affected by each people's natural environments, emotion and ways of life.

• Journal of Biosystems Engineering
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• v.10 no.2
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• pp.36-46
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• 1985

This study was intended to develop the mathematical model of the head-fed type threshing unit. As the first step, the physical model of the threshing phenomena was considered to consist of four separate processes as 1) detachment process of grains, 2) movement of grains between the cylinder and concave, 3) grain penetration through stems of bundle, and 4) grain passing through concave. The mathematical and computer models were developed based on the physical models. Threshing experiments were performed and determined the distribution of grain accumulation along the cylinder shaft by varying the moisture content of grains, feeding rate, and cylinder speed. It was found that the model developed coincided very well with the experimental results for the varied operational conditions. Greater concentration of grains passing through concave toward the thresher inlet was equally true for the model and experiment work for the threshing of grains with higher moisture content and with higher cylinder-speed. The model could be used for obtaining the optimized design or for optimizing the performance of the head-fed type threshing unit if term as to power requirement for threshing may be additionally included in the developed model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.5
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• pp.2469-2490
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• 2019

A low-energy adaptive clustering hierarchy (LEACH) protocol is a low-power adaptive cluster routing protocol which was proposed by MIT's Chandrakasan for sensor networks. In the LEACH protocol, the selection mode of cluster-head nodes is a random selection of cycles, which may result in uneven distribution of nodal energy and reduce the lifetime of the entire network. Hence, we propose a new selection method to enhance the lifetime of network, in this selection function, the energy consumed between nodes in the clusters and the power consumed by the transfer between the cluster head and the base station are considered at the same time. Meanwhile, the improved FTBA algorithm integrating the curve strategy is proposed to enhance local and global search capabilities. Then we combine the improved BA with LEACH, and use the intelligent algorithm to select the cluster head. Experiment results show that the improved BA has stronger optimization ability than other optimization algorithms, which the method we proposed (FTBA-TC-LEACH) is superior than the LEACH and LEACH with standard BA (SBA-LEACH). The FTBA-TC-LEACH can obviously reduce network energy consumption and enhance the lifetime of wireless sensor networks (WSNs).

• Tribology and Lubricants
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• v.23 no.6
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• pp.255-260
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• 2007

This paper presents the contact pressure distribution of pin bushing bearings for various lubrication friction modes such as oil film and elastohydrodynamic lubrication contacts, a mixed lubrication contact, a boundary contact, and a dry contact. During a sliding contact of a plain bearing, the boundary and dry rubbing contacts are dominated between a piston pin and a pin bushing bearing. This may come from a micro-scale clearance, an explosive impact pressures from the piston head, and an oscillatory motion of a pin bearing. The computed results show that as the oil film parameter $h/{\sigma}$ is increased from the dry rubbing contact to the oil film lubrication friction, the maximum oil film pressure is radically increased due to an increased viscous friction with a thin oil film thickness and the maximum asperity contact pressure is reduced due to a decreased asperity contact of the rubbing surfaces.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.7
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• pp.9-19
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• 2010

Fuel cell (FC) distributed generation (DG) is gradually becoming more attractive to mainstream electricity users as capacity improves and costs decrease. New technologies including inverters are becoming available to provide a uniform standard interconnection of DGs with an electric power system. Some of the operating conflicts and the effect of DG on power quality are addressed and investigated through simulations on a real distribution network with an FC power plant. The results of these simulations have proved load tracking capability following the real and reactive power change of the load and have shown the flow of overcurrent from an FC power plant during the ground fault of a distribution line.

• Journal of Power System Engineering
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• v.15 no.1
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• pp.5-10
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• 2011

The spatial fuel vapor distribution of the homogeneous charge by a 6-hole injector was examined in a optically accessed single cylinder direct injection spark ignition(DISI) engine. The effects of in-cylinder charge motion, and fuel injection pressure, and coolant temperature were investigated using a planar LIF (Laser Induced Fluorescence) technique. It was confirmed that the in-cylinder tumble flow played a little more effective role in the spatial fuel vapor distribution than the swirl flow during the compression stroke at 10 mm and 2 mm planes under cylinder head gasket and the increased fuel injection pressure activated spatial distributions of the fuel vapor. In additions, richer mixtures were concentrated around the cylinder wall by the increase of the coolant temperature.