AbstractIn this paper, a spacecraft radiator formed in a honeycomb structure is designed to enhan... more AbstractIn this paper, a spacecraft radiator formed in a honeycomb structure is designed to enhance the thermal performance while reducing its mass. Examples of design guidelines for radiator configurations, such as the distance between heat pipes, facesheet thickness, and honeycomb core density, are suggested. To derive the analytic solution of the governing equation, a linear approximation is used and the accuracies of the solutions are verified with a fourth-order finite-difference method. There exist optimal combinations of design parameters that minimize the radiator mass while maintaining its heat rejection capacity. The heat rejection rate that minimizes the mass per unit heat rejection and the pertinent radiator shape also is presented. The combinations of optimal design are different among the three surface treatments and their characteristics are investigated.
With remarkable developments in technologies, the possibility of replacing injured tissue or orga... more With remarkable developments in technologies, the possibility of replacing injured tissue or organs with artificial ones via three-dimensional bioprinting is being improved. The basic prerequisite for successful application of bioprinting is high cell survival following printing. In this study, numerical calculations and experiments were performed to understand cell damage process incurred by forced extrusion bioprinters. Compressible and shear stresses were presumed to play a pivotal role within the syringe and needle, respectively, based on numerical calculation. To verify the numerical results, two experiments—pressurization in a clogged syringe and extrusion through syringe-needle—were conducted, and the damaged cell ratio (DCR) were measured by live/dead assays. Shear stress of needle flow had a great influence on DCR of discharged bioink, whereas effect of compressible stress in clogged syringe was relatively small. Cell damage in the needle flow is affected by moving distance...
AbstractIn this paper, a spacecraft radiator formed in a honeycomb structure is designed to enhan... more AbstractIn this paper, a spacecraft radiator formed in a honeycomb structure is designed to enhance the thermal performance while reducing its mass. Examples of design guidelines for radiator configurations, such as the distance between heat pipes, facesheet thickness, and honeycomb core density, are suggested. To derive the analytic solution of the governing equation, a linear approximation is used and the accuracies of the solutions are verified with a fourth-order finite-difference method. There exist optimal combinations of design parameters that minimize the radiator mass while maintaining its heat rejection capacity. The heat rejection rate that minimizes the mass per unit heat rejection and the pertinent radiator shape also is presented. The combinations of optimal design are different among the three surface treatments and their characteristics are investigated.
With remarkable developments in technologies, the possibility of replacing injured tissue or orga... more With remarkable developments in technologies, the possibility of replacing injured tissue or organs with artificial ones via three-dimensional bioprinting is being improved. The basic prerequisite for successful application of bioprinting is high cell survival following printing. In this study, numerical calculations and experiments were performed to understand cell damage process incurred by forced extrusion bioprinters. Compressible and shear stresses were presumed to play a pivotal role within the syringe and needle, respectively, based on numerical calculation. To verify the numerical results, two experiments—pressurization in a clogged syringe and extrusion through syringe-needle—were conducted, and the damaged cell ratio (DCR) were measured by live/dead assays. Shear stress of needle flow had a great influence on DCR of discharged bioink, whereas effect of compressible stress in clogged syringe was relatively small. Cell damage in the needle flow is affected by moving distance...
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