ABSTRACT
The fatigue resistance of asphalt mixture is an important indicator to evaluate the durability of asphalt pavement. In order to improve the fatigue properties of asphalt mixture, diatomite and environmental basalt fiber were added. Four types of asphalt mixtures, ordinary asphalt mixture (AM), diatomite modified asphalt mixture (DAM), basalt fiber modified asphalt mixture (BFAM) and diatomite/basalt fiber composite modified asphalt mixture (DBFAM), were chosen, whose optimum asphalt-aggregate ratio, optimum content of diatomite and optimum content of basalt fiber could be determined by Marshall test and response surface methodology (RSM). The multi-functional pneumatic servo Cooper test machine was carried out by a four-point bending fatigue test. Through the comparative analysis of flexural-tensile stiffness modulus (S), initial stiffness modulus(S0), residual stiffness modulus ratio, lag angle (Ï) and cumulative dissipation energy (ECD), the fatigue resistance of asphalt mixture can be effectively improved by adding diatomite and basalt fiber. Grey correlation analysis was also used to analyze the degree of correlation between the fatigue life and the influencing factors such as VV, VMA, VFA, OAC, S, and ECD. The analysis results indicate that ECD has the greatest impact on the fatigue life of the asphalt mixture.
ABSTRACT
OBJECTIVE: Differences in clinical features, especially facial nerve canal leision between cholesteatoma in external auditory meatus and middle ear were compaired. METHOD: A retrospective clinical analysis was made. Clinical data included 125 cases of middle ear cholesteatoma with facial nerve canal leision and 28 cases of cholesteatoma occurred in external auditory canal from 2003-01-2014-08 in our hospital. RESULT: Clinical course of cholesteatoma in external auditory canal was 4.97 ± 7.51 years, course of middle ear cholesteatoma was 16.60 ± 14.42 years (P < 0.01). 21 cases (75%) of external auditory canal cholesteatoma were manifested as pneumatic mastoid and 110 cases (88%) of middle ear cholesteatoma were manifested as diploic mastoid respectively. 22 cases (78.6%) of facial nerve canal damage-in mastoid segment in cholesteatoma of external auditory meatus and 76 cases (60.8%) of facial nerve canal damage in tympanic segment in cholesteatoma of middle ear were observed (P < 0.01). The incidence rate of ossicular errosion in middle ear chol-esteatoma was significantly higher than that in external auditory meatus (P < 0.01). The incidence of semicircular canal defects in middle ear cholesteatoma (30.4%), was significantly higher when comparing to the incidence (10.7%) in cholesteatoma of external auditory meatus (P < 0.05). CONCLUSION: The site of facial nerve canal lesion in middle ear cholesteatoma and cholesteatoma of external auditory meatus were different. More attention should be paid before and during operation to avoid facial nerve injury, including physical examinations, especial otologic exams, radiological reading and careful operation.
