Quality control is an important part of the capacitors automatic assembly process. Traditionally this control is being realized through a series of electrical measurements including capacity, tension, and tgct. In mos...Quality control is an important part of the capacitors automatic assembly process. Traditionally this control is being realized through a series of electrical measurements including capacity, tension, and tgct. In most cases, these measurements are not suitable for detecting defects that appear as a result of failures of certain elements of the assembly lines. These so called self-recovering failures very often remain unnoticed, because they do not cause a suspension of the assembly process and if not taken into consideration, they can seriously menace the final product quality. In this paper, the authors use PFMEA to identify and evaluate the risk of the self-recovering failures. They also propose a simple Simulink model, which could be useful when trying to estimate the effect of installing new control devices at an existing assembly line upon its overall reliability and productivity.展开更多
An understanding of soil thermal conductivity after a wildfire or controlled burn is important to land management and post-fire recovery efforts. Although soil thermal conductivity has been well studied for non-fire h...An understanding of soil thermal conductivity after a wildfire or controlled burn is important to land management and post-fire recovery efforts. Although soil thermal conductivity has been well studied for non-fire heated soils, comprehensive data that evaluate the long-term effect of extreme heating from a fire on the soil thermal conductivity are limited. The purpose of this study was to evaluate the long-term impact of fire on the effective thermal conductivity of soils by directly comparing fire-heated and no-fire control soils through a series of laboratory studies. The thermal conductivity was measured for ten soil samples from two sites within the Manitou Experimental Forest, Colorado, USA, for a range of water contents from saturation to the residual degree of saturation. The thermal conductivity measured was compared with independent estimates made using three empirical models from literature, including the Campbell et al. （1994）, CSt~ and Konrad （2005）, and Massman et al. （2008） models. Results demonstrate that for the test soils studied, the thermal conductivity of the fire-heated soils was slightly lower than that of the control soils for all observed water contents. Modeling results show that the Campbell et al. （1994） model gave the best agreement over the full range of water contents when proper fitting parameters were employed. Further studies are needed to evaluate the significance of including the influence of fire burn on the thermal properties of soils in modeling studies.展开更多
文摘Quality control is an important part of the capacitors automatic assembly process. Traditionally this control is being realized through a series of electrical measurements including capacity, tension, and tgct. In most cases, these measurements are not suitable for detecting defects that appear as a result of failures of certain elements of the assembly lines. These so called self-recovering failures very often remain unnoticed, because they do not cause a suspension of the assembly process and if not taken into consideration, they can seriously menace the final product quality. In this paper, the authors use PFMEA to identify and evaluate the risk of the self-recovering failures. They also propose a simple Simulink model, which could be useful when trying to estimate the effect of installing new control devices at an existing assembly line upon its overall reliability and productivity.
基金supported by the National Science Foundation (NSF), USA (division of graduate education, No.DGE-0638719)
文摘An understanding of soil thermal conductivity after a wildfire or controlled burn is important to land management and post-fire recovery efforts. Although soil thermal conductivity has been well studied for non-fire heated soils, comprehensive data that evaluate the long-term effect of extreme heating from a fire on the soil thermal conductivity are limited. The purpose of this study was to evaluate the long-term impact of fire on the effective thermal conductivity of soils by directly comparing fire-heated and no-fire control soils through a series of laboratory studies. The thermal conductivity was measured for ten soil samples from two sites within the Manitou Experimental Forest, Colorado, USA, for a range of water contents from saturation to the residual degree of saturation. The thermal conductivity measured was compared with independent estimates made using three empirical models from literature, including the Campbell et al. （1994）, CSt~ and Konrad （2005）, and Massman et al. （2008） models. Results demonstrate that for the test soils studied, the thermal conductivity of the fire-heated soils was slightly lower than that of the control soils for all observed water contents. Modeling results show that the Campbell et al. （1994） model gave the best agreement over the full range of water contents when proper fitting parameters were employed. Further studies are needed to evaluate the significance of including the influence of fire burn on the thermal properties of soils in modeling studies.
