• Journal of the Korean Society for Precision Engineering
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• v.29 no.6
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• pp.680-685
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• 2012

Ceramic femoral heads are now widely used in Total Hip Replacement (THR). Due to their high biocompatibility and low ductility, ceramic femoral heads are considered to be suitable for young and active patients. However, as in testing the mechanical stability of the femoral head, the conventional proof test (standard ISO 7206-10) has its limit of showing axisymmetric stress distribution on the contact surface, while non-uniformed stress distribution is expected after THR. Since non-uniformed stress distribution can result in the increased probability of ceramic femoral head fracture, it is considerable to evaluate the stress distribution in vivo-like conditions. Therefore, this study simulated the ceramic femoral heads under in vivo-like conditions using finite element method. The maximum stress decreased when increasing the size of the femoral head and stress distribution was concentrated on superior contact surface of the taper region.

• The KSFM Journal of Fluid Machinery
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• v.9 no.2 s.35
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• pp.44-49
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• 2006

In this study, the effects of volute area distribution on the performance of a centrifugal pump were numerically studied using a commercial CFD code. To reduce the shutoff head, maintaining head and efficiency at a design flow rate, the flat head-capacity characteristic curves in which the head varies only slightly with capacity from shutoff to design capacity are frequently required. In order to control the shutoff head of a pump, several volute cross-sectional area distributions were proposed as a main parameter with the same impeller geometry The calculation results show that the slope of the performance characteristic curve of the centrifugal pump can be controlled by modifying the area distribution from volute tongue to volute outlet with fixed volute outlet area and also varied volute outlet area.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.497-502
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• 2005

In this study. the effect of volute area distribution on the performance of a centrifugal pump were numerically studied using a commercial CFD code. To reduce the shutoff head, maintaining head and efficiency at a design flow rate. the flat head-capacity characteristic curves in which the head varies only slightly with capacity from shutoff to design capacity are frequently required. In order to control the shutoff head of a pump, several volute cross-sectional area distributions were proposed as a main parameter with the same impeller geometry. The calculation results show that the slope of the performance characteristic curve of the centrifugal pump can be controlled by modifying the area distribution from volute tongue to volute outlet with fixed volute outlet area and also varied volute outlet area.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.558-563
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• 2005

In this paper, the effect of volute area distribution on the performance characteristic curve of a centrifugal pump were numerically studied using a commercial CFD code. To reduce the shutoff head, maintaining head and efficiency at a design flow rate, the flat head-capacity characteristic curves in which the head varies only slightly with capacity from shutoff to design capacity are frequency required. In order to control the shutoff head of a pump, several volute area distributions were proposed as a main parameter with the same impeller geometry. The calculation results show that the characteristic curve of a centrifugal pump can be controlled by modifying the area distribution with the same volute outlet area.

• The Journal of Korean Physical Therapy
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• v.7 no.1
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• pp.33-42
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• 1995

The purposes of this study were 1) to compare weight distribution and ratio of the extremities between normal and hemiplegic children in quadruped position and 2) to compare the effect of ATNR on weight bearing of the extremities between normal and hemiplegic children. The subjects fer the study were 48 children(24 normal, 24 hemiplegic) between the ages 3 to 6. They were teated weight distribution and ratio of the extremities in the neutral position of head and by passive right and left rotation of the head in the quadruped position. The data wert analized by paired t-test. The results were as follows: 1. In the neutral position of head, normal group was not difference on weight distribution and ratio of the extremities and hemiplegic group was more weight bearing on the sound upper extremity than the affected upper extremity(p<.01). 2. When the head rotated to the dominant side or sound side passively, there was not a significant difference between normal and hemiplegic group. 3. When the head rotated to the nondominant side or affected side passively, there was a significant difference between nondominant upper extremity nf normal and affected upper extremity of hemiplegic group(p<.05).

• Journal of the Korean Society of Food Culture
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• v.29 no.6
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• pp.488-498
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• 2014

The research aimed to provide accurate and basic data comparing different perceptions of head family's food and food for religious ceremonies depending on age with the goal of sustaining traditional Korean food in the future. The gender distribution of the participants was 274 Males (42.5%) and 370 Females (57.5%). Age distribution was 211 participants (32.7%) in their 20s, 215 participants (33.3%) in their 30 to 40s, and 220 participants (34%) in their 50 to 60s. The older generation appeared to beaware of the definition of head family or 'The eldest's house of head family' as well as the concept of one's family five generations ago with more reductive and emphasis than imaginary concept of head family of the younger generation. The image of the head family was perceived as 'head family's food' in younger generations and as 'eldest son' in older generations. Family role and meaning most often manifested as 'succession of tradition' and 'cultural symbols' in younger generations, respectively, whereas older generations responded 'hallmark of the head family'. Family ancestral rites and head family's food had positive effects on awareness of head family's food. Moreover, those with experience in practicing family ancestral rites responded that head family's food should be more popular. People who viewed family's food more positively were more open with the idea thathead family's food could go mainstream. In conclusion, positive perception of head family's food and traditional pride are crucial environmental factors in public support of popularizing head family's food to the public.

• The korean journal of orthodontics
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• v.15 no.2
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• pp.211-227
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• 1985

The purpose of this study was to analyze the stress distribution and the displacement in the maxillary complex after the application of the three kinds of the head gear. (high pull head gear, straight pull head gear, cervical pull head gear.) Orthopedic force, 300 gram, was applied to the maxilla of the dry human skull in a high, straight and cervical direction. The stress distribution and the displacement within the maxillary complex was analyzed by a 3-dimensional finite element method. The results were as follow: 1. In won, the stress of conical pull head gear was the greatest stress and straight pull head gear was the medium stress and high pull head gear was the least stress. 2. The compressive stress was observed on the anterior portion of premaxilla, especially anterior nasal spine area, when the three kinds of head gear were applied to the dry kuman skull. 3. It appeared that the stress of the anterior portion of the zygomatic bone was greater than the posterior portion in the case of three kinds of head gear application and compressive stress was noted only at the below of the frontozygomatic suture of the zygomatic bone. 4. The backward, upward, sideward displacement of the alveolar area was observed in a high pull head gear application but in the case of straight pull head gear and cervical pull head gear application, the backward, downward, sideward displacement was observed. 5. The forward, downward, sideward displacement was observed on the midpalatine suture and premaxilla on the sagittal plane and transverse palatine suture in the case of three kinds of headgear application.

• Journal of the Korean Society of Safety
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• v.32 no.4
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• pp.16-21
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• 2017

The sprinkler system is a basic fire extinguishing system that uses water as an extinguishing agent. In order to evaluate the fire extinguishing performance of the sprinkler system, information such as the discharge angle, discharge speed, discharge pressure, flow rate, and water droplet size of the installed head are required. However, there is a lack of research on droplets size compared to other requirements. In this study, to evaluate the extinguishing characteristics of sprinkler system, the droplet size distribution was measured for various types of sprinkler heads actually used. The size of the droplet was measured using laser diffraction method. The 50% cumulative volume distribution ($D_{v50}$) according to discharge coefficient(K factor) was $540{\mu}m{\sim}695{\mu}m$ for K50, $542{\mu}m{\sim}1,192{\mu}m$ for K80, $980{\mu}m{\sim}1,223{\mu}m$ for K115 and $1,188{\mu}m{\sim}1,234{\mu}m$ for K202. Based on the measured results, the vaeiance of the droplet particle distribution and the distribution ($D_{v50}$) according to discharge coefficient(K factor) was $540{\mu}m{\sim}695{\mu}m$ for K50, $542{\mu}m{\sim}1,192{\mu}m$ for K80, $980{\mu}m{\sim}1,223{\mu}m$ for K115 and $1,188{\mu}m{\sim}1,234{\mu}m$ for K202. Based on the measured results, the vaeiance of the droplet particle distribution and the Rosin-Rammler index value are presented. As a result of the fire simulation with FDS, it was confirmed that the performance difference occurs according to the water droplet size distribution even when the same amount of water is used. Therefore, the extinguishing performance of the sprinkler system should be evaluated considering the droplet size distribution according to the sprinkler head type.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.4
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• pp.27-33
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• 2001

In this study, it is observed that the distribution of combustion chamber volume affects the volumetric efficiency. The distribution ratio was adjusted by controlling combustion chamber volume of head and piston bowl one. Four cases were investigated, which are the combination of different distribution ratios and different compression ratios (9.8-10.0). A commercial SOHC 3-valve engine was modified by cutting the bottom face of the head and/or replacing the piston by the one that has different volume. The result shows that the less the head side volume, the more volumetric efficiency is achieved under the same compression ratio. It is also observed that increasing volumetric efficiency results in early knock occurrence due to increased "real" compression ratio. To consider reliability in estimating the volumetric efficiency, we examined the sensitivity of the AFR equation to possible errors in emission measurements. It is shown that the volumetric efficiency, which is calculated by measuring AFR and fuel consumption, can be controlled in 1% error. 1% error.

• Korean journal of applied entomology
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• v.22 no.1 s.54
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• pp.45-47
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• 1983

The d/w ratio, initially proposed for measuring resource utilization of an organism, was introduced for an objective description of the larval head width distribution in a holometabolous insect. The statistical method was successfully applicated in the case of Sitophilus oryzae, and, therefore, could be also used for characterizing the larval head width distribution of other insects.