Rolling contact fatigue(RCF) is a major cause of failure that appears in components of rolling contacts. In the recent years, the fatigue propagation and failure have been an important issue in respect of the safe operation and to reduce the noise and vibration of the rolling contact components. The water-contaminated lubrication is known to be one of the significant factors that reduces the lifetime of the rolling contact components. Thus, in this study, the effect of water-contaminated lubrication environment on the rolling contact fatigue was investigated. Bearing life testing was performed in two different lubrication conditions (i.e. normal lubrication environment and water-contaminated lubrication environment). The effect of the debirs on the rolling contact fatigue could be eliminated by establishing the debris filter system. Microscopic features of the rolling contact surfaces were examined using energy dispersive spectrometry and non-contact 3D measurement system. In the case of the water-contaminated lubrication, the increase of surface roughness values up to 17.6% was observed. The oxidation state and pattern of the rolling contact surfaces were very different depending on the lubrication environment. It was also found that the bearing rating life, , was decreased significantly in the watercontaminated lubrication condition. The amount of reduction was about 49.7%.
The morphology of the lingual papillae in a female Bengal tiger (Panthera tigris tigris) was examined by scanning electron microscopy (SEM). The tongue was 22.3 cm in length and 7.1 cm in width. Numerous filiform papillae were distributed over the entire dorsal surface of the tongue. SEM examination of the tongue revealed two types of mechanical papillae, i.e. filiform and conical papilla, and two types of gustatory papillae, i.e. fungiform and vallate papilla, on the dorsal surface of the tongue. Each filiform papilla consisted of one primary papilla and several secondary papillae. The filiform papillae on the anterior part of the tongue were divided into one primary and 6~14 secondary papillae. Unlike other mammalians, however, secondary papillae in the mid-part of the tongue showed pineal-like papillae. In the posterior part of the tongue, secondary papillae were rare or absent. Fungiform papillae were surrounded by filiform papillae and densely distributed on the lingual surface. There were two vallate papillae on the borderline between the lingual body and root of the tongue. A vallate papilla contained two secondary papillae inside the grooves. Conical papillae were located in the area of the vallate papillae and covered the posterior part of the tongue root. No foliate papillae were seen on both margins of the posterior part of the tongue. Our results indicate that the structure on the lingual papillae of the Bengal tiger is somewhat different from that of other mammals.
The aim of this study was to investigate the morphological development pattern of conical papilla (CP) during prenatal and postnatal periods in native Korean goats by scanning electron microscopy. Tongues were removed from fetuses on days 90, 120, and neonates and from juveniles on days 30, 50, 60, 75, 90, 120, 150, and 180 after birth. The lengths of CP were 194~240 μm in neonates, 335~485 μm in the weaning period of 60-day-old goats, and 526~662 μm in the maturing period of 180-day-old goats. The primordia of CP in 90-day-old fetuses, shaped like mountain berry, were sprouted. The CP of 120-day-old fetuses was a cylinder shape with an apex whose center was slightly concave and the margin was sticking up like a low fence. The CP of neonates was empty inside and the secondary papillae were irregularly arranged fence-like structures on it. In 60-day-old goats, CP was an obliquely sectioned cylinder shape compacted in inner surface; the shapes of CP varied in 120-day-old goats, and had a smooth surface. A low elevation of CP was observed in 150- and 180-day-old goats. The microridges, microplicae, and micropits were well developed on the epithelial surface of lingual papillae in 60- to 120-day-old goats. These findings indicate that CP of goats has a variety of sizes and shapes during development.
국내 주요지역에서 생산되는 곶감 및 표면 백색분말의 당조성과 분말의 형태를 주사전자현미경으로 관찰하였다. 곶감과육의 당함량은 56~59% 정도였으며 주로 glucose와 fructose로 이루어져 있었다. 백색분말은 당 84.6%, 수분 12.5% 및 불용성 물질이 2.7% 정도였으며 당조성에 있어서는 glucose가 83.3%를, fructose가 16.7%로 대부분이 glucose였다. 백색분말을 주사전자현미경으로 관찰한 결과 판, 꽃, 침 및 뿔등의 형태를 이루고 있었으며 수화후 재결정화한 glucose와 비슷한 형태를 나타내었다. 곶감 표면의 백색분말은 건조과정중 과육내부의 당이 수분의 이동과 함께 건조표면으로 이동하여 건조가 진행됨에 따라 주로 glucose가 결정화된 것으로 보여진다.
The present study concerns a measurement of porosity at the nano-fibre interface in concrete. Concrete cast with a centrally located nano-fibre (Ø0.39 × 15.0 mm) was segmented for microscopic observation at a bascattered electron (BSE) image. As a result, it was found that the pores generated in the vicinity of the nano-fibre ranged from 5.40 to 11.45%, equivalent to 0.51 - 1.08% of air void in a bulk concrete.