Comparative Study on the Infrared Radiance Field of Building Surface under Sunshine Conditions and Rainfall Conditions

The Monte Carlo method and the region method are combined in this paper,where a high-rise building in Harbin were taken for example to investigate the infrared radiation field of building surface.The calculation models of temperature field and radiation transfer coefficient on the exterior surface were established.Through the self-built Bidirectional Reflectance Distribution Function(BRDF)experimental device,the BRDFs of moorstone,aluminum plate,coated glass and Ethylene-Propylene-Diene Monomer(EPDM)on the surfaces under dry and wet conditions were measured at different incidence angles with respective laser wavelengths of0.6328μm and 1.34μm.For the two wavelengths,the reflection ratios of the material surfaces under dry and wet conditions were calculated respectively.Based on some proper simplifications of the background condition,the simulation analysis of the radiation field of building surface was carried out according to the wetness theory and the measured data.Taking the situation at 9:00 a.m.on the day of summer solstice as an example,this paper made relevant quantitative calculation for the solar radiation,the self radiation of the surface units,the radiating projection between the surface units,and the general infrared radiation of the building surface.Comparisons on infrared radiance field of the building surface were obtained under cloud-free sunshine conditions and rainfall conditions respectively,and the rationality of the results was discussed.

Cleated Print Surface for Fused Deposition Modeling

FDM （fused deposition modeling） has become popular among Additive Manufacturing technologies due to its speed, geometric scalability, and low cost; however, the primitive nature of the FDM build surface fundamentally limits the utility of FDM in terms of reliability, autonomy, and material selection. Currently, FDM relies on adhesive forces between the first layer of a print and the build surface; depending on the materials involved, this adhesive bond may or may not be reliable. Thermal contraction between the build plate and build materials can break that bond, which causes warpage and delamination of the part from the build surface and subsequent failure of the part. Furthermore, with each print, the user must use tools or manual maneuvering to separate the printed part from the build surface as well as retexture or replace the used build surface. In this paper, we present a novel build platform that allows for a mechanical bond between the print and build surface by using dovetail-shaped features. The first layer of the print flows into the features and becomes mechanically captivated by the build platform. Once the print is completed, the platform is rolled or flexed open to release the part from the mechanical bond. This design not only lowers the risk of delamination during printing but also eliminates the need for a user to reset or replace the build surface between print jobs. The effectiveness of each geometry was determined by measuring the distance at the pinch point compared to the distance that the extrusion filled below the pinch point. The captivation ratio was measured to compare the different geometries tested and determine which direction of extrusion creates a better ratio.