Generation of Porous Structures Using Fused Deposition

The Fused Deposition Modeling process uses hardware and software machine-level language that are very similar to that of a pen-plotter. Consequently, the·use of patterns with poly-lines as basic geometric features, instead of the current method based on filled polygons (monolithic models), can increase its efficiency. In the current study, various toolpath planning methods have been developed to fabricate porous structures. Computational domain decomposition methods can be applied to the physical or to slice-level domains to generate structured and unstructured grids. Also, textures can be created using periodic tiling of the layer with unit cells (squares, honeycombs, etc). Methods 'based on curves include fractal space filling curves and.change of effective road width Within a layer or within a continuous curve. Individual phases can also be placed in binary compositions. In present investigation, a custom software has been developed and implemented to generate build files (SML) and slice files (SSL) for the above-mentioned structures, demonstrating the efficient control ofthe size, shape, and distribution ofporosity.Mechanical Engineerin

Virtual Simulation for Multi-material LM Process

In an ONR funded MURI program, to improve quality of multi-material parts, we've been developing an advanced computer simulation for the multi-material layered manufacturing (LM) process. The CAD models and their .stLfiles are created using. the commercially available software such as I-DEAS and ProE. Using this information, one tool path file per material is generated. Our file preparation algorithm, systematically, layer by layer, integrates all tool path files into one multi-material tool path file. The results of the multi-material tool path are graphically visualized using the simulation algorithm (written in c++ & SGI OpenGL). From a virtual simulation, we can check the LM process, and make the best selection of tool path parameters afterwards. After several trials from design to simulation, if the simulation result is acceptable, the real manufacturing can be started. And the part's quality should be better than a part manufactured without running simulation in advance. This paper will represent .•. new studies on using real toadshapes to get more realistic simulation results. Many parts have been successfully simulated using our method.Mechanical Engineerin

Household decision-making about delivery in health facilities: evidence from Tanzania.

This study investigated how partners' perceptions of the healthcare system influence decisions about delivery-location in low-resource settings. A multistage population-representative sample was used in Kasulu district, Tanzania, to identify women who had given birth in the last five years and their partners. Of 826 couples in analysis, 506 (61.3%) of the women delivered in the home. In multivariate analysis, factors associated with delivery in a health facility were agreement of partners on the importance of delivering in a health facility and agreement that skills of doctors are better than those of traditional birth attendants. When partners disagreed, the opinion of the woman was more influential in determining delivery-location. Agreement of partners regarding perceptions about the healthcare system appeared to be an important driver of decisions about delivery-location. These findings suggest that both partners should be included in the decision-making process regarding delivery to raise rates of delivery at facility