RESUMO
The mechanical strength of an Al-30% Si alloy in the mushy zone was estimated by using a novel centrifugation apparatus. In the apparatus, the alloy melt was partially solidified, forming a porous structure made of primary Si platelets (Si foam) while cooling. Subsequently, pressure generated by centrifugal force pushed the liquid phase out of the foam. The estimated mechanical strength of the Si foam in the temperature range 850-993 K was very low (62 kPa to 81 kPa). This is about two orders of magnitude lower than the mechanical strength at room temperature as measured by compressive tests. When the centrifugal stress was higher than the mechanical strength of the foam, the foam fractured, and the primary Si crystallites were extracted along with the Al-rich melt. Therefore, to maximize the centrifugal separation efficiency of the Al-30% Si alloy, the centrifugal stress should be in the range of 62-81 kPa.
RESUMO
PURPOSE: The purpose of this study was to investigate the relationships among variables of somatic attribution, chronic pain, depression and chronic fatigue in the elderly. METHODS: Empirical data for testing hypothetical models was collected from 311 people over 65 years old in a community settings in Seoul, Korea in June and July, 2000. Data were analyzed by descriptive statistics and correlational analysis using pc-SAS program. The Linear Structural Modeling(LISREL) 8.0 program was used to find the best fit model which explained causal relationship of variables. RESULT: According to Accepted model, the relation of variables is that the somatic attribution is the influencing variable to chronic pain and depression and chronic pain and depression is the influencing variable to chronic fatigue. CONCLUSION: The findings of this study give useful information to construct intervention program relating chronic pain, depression and chronic fatigue for the elderly.
