• Clinics in Shoulder and Elbow
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• 제24권1호
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• pp.15-20
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• 2021

Background: The presence of an acromial spur implies a rotator cuff disorder due to impingement between the acromial spur and the rotator cuff. The purpose of the study was to observe acromial spurs using ultrasonography and to compare measurements between plain radiographs and sonograms. Methods: We retrospectively enrolled 51 consecutive patients with acromial spurs, which were interpreted on preoperative plain radiographs (supraspinatus outlet view and 30° caudal tilt) and preoperative sonograms. The ultrasonography transducer was held vertically and continuously moved laterally, which corresponded to the long axis of the long head of the biceps. The distance from the most distal margin of the original acromion to the most projected point of the acromial spur was measured. Results: No significant difference was found between the plain radiograph and ultrasonography measurements (p=0.186). A moderate to strong correlation was detected between the ultrasonography and supraspinatus outlet-view measurements (r=0.776, p=0.000). Conclusions: Anteriorly projected acromial spurs were well-visualized by ultrasonography. No discrepancy in acromial spur length was detected between the use of plain radiography (supraspinatus outlet view and 30° caudal-tilt view) and ultrasonography. The correlation coefficients between the plain radiography and ultrasonography measurements exceeded 0.7.

• 한국농림기상학회지
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• 제7권3호
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• pp.192-200
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• 2005

본 연구는 배 신고 품종의 영양 진단을 위해 과총 잎과 신초 잎을 구별한 무기성분 변화와 기상요인이 잎의 무기성분 함량에 미치는 영향을 조사하였다 과총 잎의 N, P, K, Mg 함량은 후기로 갈수록 감소되었으나, Ca, Mn 함량은 증가되었다. N, P, K, Fe 함량은 과총 잎과 신초 잎의 함량 차이가 거의 없었다. 과총 잎의 Ca, Mn, Cu, Zn성분은 신초 잎보다 높았으나, B 성분은 신초 잎보다 낮았다. 신초 잎의 N 성분은 평균 기온과는 정의 상관이, 최고 기온과는 부의 상관이 인정되었다. 과총 잎의 P 성분과 최고 기온과는 부의 상관이 인정되었다. 과총 잎의 Ca 성분은 평균 기온과는 부의 상관이, 최고, 최저 기온과는 정의 상관을 보였다. 신초, 과총 잎의 Mg, B 성분과 평균 기온과는 정의 상관이, 최고, 최저 기온과는 부의 상관이 인정되었다. 일반적인 잎 채취 시기인 7월 중순${\~}$8월 상순 사이의 과총 잎 내 Ca, Mn 함량은 신초 잎보다 확연히 높았기 때문에 정확한 영양진단을 위해서는 신초 잎과 과총 잎을 구별하여 채취하는 것이 좋을 것으로 판단된다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2017년도 춘계공동학술대회
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• pp.17-17
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• 2017

In electric agricultural machine the gearhead is needed to convert the high speed low torque rotation motion generated by DC motor to lower speed high torque motion used by the vehicle. The gearhead consist of several spur gears works as reduction gears. Spur gear have straight tooth and are parallel to the axis of the wheel. Spur gears are the most easily visualized gears that transmit motion between two parallel shafts and easy to produce. The modeling and simulation of spur gears in DC motor gearhead is important to predict the actual motion behavior. A pair of spur gear tooth in action is generally subjected to two types of cyclic stress: contact stress and bending stress including bending fatigue. The stress may not attain their maximum values at the same point of contact fatigue. These types of failure can be minimized by analysis of the problem during the design stage and creating proper tooth surface profile with proper manufacturing methods. To improve its life expectation in this study modal and stress analysis of gearhead is simulated using ansys work bench software based on finite element method (FEM). The modal analysis was done to understand gearhead deformation behaviour when vibration occurs. FEM static stress analysis is also simulated on gearhead to simulate the gear teeth bending stress and contact stress behavior. This methodology serves as an approach for gearhead design evaluation, and the study of gear stress behavior in DC motor gearhead which is needed in the small workshop scale industries.

• Journal of Korean Neurosurgical Society
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• 제46권4호
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• pp.328-332
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• 2009

Objective : The purpose of this study was to establish new fusion criteria to complement existing Brantigan-Steffee fusion criteria. The primary purpose of intervertebral cage placement is to create a proper biomechanical environment through successful fusion. The existence of a traction spur is an essential predictable radiologic factor which shows that there is instability of a fusion segment. We studied the relationship between the existence of a traction spur and fusion after a posterior lumbar interbody fusion (PLIF) procedure. Methods : This study was conducted using retrospective radiological findings from patients who underwent a PLIF procedure with the use of a cage without posterior fixation between 1993 and 1997 at a single institution. We enrolled 183 patients who were followed for a minimum of five years after the procedure, and used the Brantigan-Steffee classification to confirm the fusion. These criteria include a denser and more mature bone fusion area than originally achieved during surgery, no interspace between the cage and the vertebral body, and mature bony trabeculae bridging the fusion area. We also confirmed the existence of traction spurs on fusion segments and non-fusion segments. Results : The PLIF procedure was done on a total of 251 segments in 183 patients (71 men and 112 women). The average follow-up period was $80.4{\pm}12.7$ months. The mean age at the time of surgery was $48.3{\pm}11.3$ years (range, 25 to 84 years). Among the 251 segments, 213 segments (84.9%) were fused after five years. The remaining 38 segments (15.1%) were not fused. An analysis of the 38 segments that were not fused found traction spur formation in 20 of those segments (52.6%). No segments had traction spur formation with fusion. Conclusion : A new parameter should be added to the fusion criteria. These criteria should be referred to as 'no traction spur formation' and should be used to confirm fusion after a PLIF procedure.

• Tribology and Lubricants
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• 제32권4호
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• pp.113-118
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• 2016

As an economic, high quality, and highly reliable gear with low noise and low vibration is demanded, an overall finite element analysis regarding a gear is required. Also, an infrared thermography test, which is a quantitative testing technique, is demanded for safety and longer lifespan of gear products. In order to manufacture a gear product or to determine safety of a gear being used, it is necessary to precisely determine ingredients of a material constituting a gear and detect any internal defect. This study aims to realize a design that minimizes the spur gear displacement with respect to power during its rotation and ensures the spur gear control capacity by using a 3D model and the midasNFX program. This facilitates the assessment of the possibility of cracking by evaluating the stress intensity and focusing on the integrity of the spur gear. We prepare the specimen of the spur gear based on the possibility of cranking as per the result of the structural interpretation from an infrared ray thermal measuring technique. After cooling the spur gear, we perform experiments using thermography and halogen lamps and analyze the temperature data according to the results of the experiment. In the experiment which we use thermography after cooling, we find a rise in the temperature of the room. As a result, the defective part show temperatures lower than their surroundings while the normal parts have temperatures higher than the defective parts. Therefore, it possible to precisely identify defective part owing to its low temperature.

• 한국물환경학회지
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• 제26권3호
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• pp.468-473
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• 2010

The purpose of this study is to derive the correlation between the Specific Phosphorus Release Rate (SPRR), Specific Phosphorus Uptake Rate (SPUR) and Specific Oxygen Uptake Rate (SOUR) at various Sludge Retention Time (SRT) condition in the A/O process. The laboratory scale reactor was operated on various SRT (10 day, 20 day, 30 day, 40 day). In this study, the SPRR, SPUR and SOUR tended to decrease with the SRT increase. Empirical equations was be obtained $y=4.54E-006x^2+0.0007x-0.0315$, $R^2=0.925$ (SOUR vs. SPRR) and $y=3.22E-006x^2+0.0004x-0.0173$, $R^2=0.928$ (SOUR vs. SPUR) from the relationship between SRT, SPRR and SPUR and SOUR. Therefore, the anaerobic tank design based on the research result such as SPRR, SPUR of a phosphorus design and SOUR would be possible.

• 대한기계학회논문집A
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• 제33권4호
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• pp.440-446
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• 2009

This paper was designed to fabricate the miniature spur gear with pitch circle of 2.25mm using extrusion process of a mechanically alloyed Al-78wt%Zn powder. The mechanical alloying of the powder particles were performed for ball milled times of 4h, 8h, 16 and 32h by the planetary ball milling. The mechanical properties of these alloyed powders, which were compacted and sintered-cylindrical preforms, were estimated using compression test. The results showed that the alloyed powder with average particle size of $10{\mu}m$ milled for 32h has the highest compressive(fractured) strength(288MPa). Extrusions of the miniature spur gear using the alloyed powder were carried out at different extrusion temperatures. Extrusion temperature of $300^{\circ}C$ provided the spur gear with the highest relative density and Vickers hardness and without any surface defects.

• 한국안전학회지
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• 제9권3호
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• pp.28-33
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• 1994

It is very important to have exact informations on the properties and characteristics of the sintering material as a new material of machine elements. To study the sintering spur gear and the sintering specimen to be consisted of Fe-Cu-C, the constant stress amplitude fatigue test is performed by using an electrohydrolic survo-controlled pulsating tester. Consequently, the S-N curves are obtained and the fatigue strength is compared with flaw depth. Accordingly, this study presents the fatigue strength of sintering spur gears, the critical notch depth of sintering materials and the effects of flaw depth on the bending fatigue strength.

• Tribology and Lubricants
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• 제18권6호
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• pp.418-424
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• 2002

The basic concept of ‘gear profile modification’ is to change a part of the involute profile to reduce the load in that area and appropriate profile modifications can help gears to run quietly and resist scoring., pitting, and tooth breakage. In this study, the modification of tooth profile to make a smooth transmission of the normal loads in spur gears has been developed. The modified tooth profile has been determined by the total deflection at contact points. We also compared our results with other experimental results.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 추계학술대회논문집
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• pp.172-175
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• 1997

The conventional closed-die forgings had been applied to the forging of spur gears. But the forgings require high forging-pressure. In this paper, new precision forging technology have been developed. The developed technology is two steps forging process. Good shaped products are forged successfully with lower forging-pressure than those of conventional forging