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Design and additive manufacturing of porous titanium scaffolds for optimum cell viability in bone tissue engineeringPore size, external shape, and internal complexity of additively manufactured porous titanium scaffolds are three primary determinants of cell viability and structural strength of scaffolds in bone tissue engineering. To obtain an optimal design with the combination of all three determinants, four scaffolds each with a unique topology (external geometry and internal structure) were designed and varied the pore sizes of each scaffold 3 times. For each topology, scaffolds with pore sizes of 300, 400, and 500 µm were designed. All designed scaffolds were additively manufactured in material Ti6Al4V by the direct metal laser melting machine. Compression test was conducted on the scaffolds to assure meeting minimum compressive strength of human bone. The effects of pore size and topology on the cell viability of the scaffolds were analyzed. The 12 scaffolds were ultrasonically cleaned and seeded with NIH3T3 cells. Each scaffold was seeded with 1 million cells. After 32 days of culturing, the cells were fixed for their three-dimensional architecture preservation and to obtain scanning electron microscope images.
This paper documents the effects of an additive manufacturing course on two sets of students: (1) the undergraduates who took the course and (2) the middle and high school students who visited our labs. At the time of the conference, nine semesters of data (three years at three schools) will have been collected, as well as data from the middle and high school students who visited our labs. Overall, our research questions were: (1) what is the effect of this course on the content knowledge of (a) enrolled undergraduates and (b) middle and high school students? And (2) what is the effect of this course on the attitudes towards engineering and self-efficacy in engineering for (a) enrolled undergraduates and (b) middle and high school students? To determine the answers, our longitudinal matched-pairs data collection was conducted. In short, as measured by t-test, all students improved on content knowledge (p less than .01), but female students improved slightly more than male students (+9.89 versus +9.01, respectively). Undergraduates did not change their minds about the factors that are important in engineering, although they did significantly change their self-efficacy ratings in some skills because of the course. In particular, undergraduates rated themselves highermore »
Assessing the Results of an Additive Manufacturing Course at Three Large Universities on Undergraduates and High School StudentsAdditive manufacturing (AM) is prevalent in academic, industrial, and layperson use for the design and creation of objects via joining materials together in a layer upon layer fashion. However, few universities have an undergraduate course dedicated to it. Thus, using NSF IUSE support [grant number redacted for review] from the Exploration and Design Tier of the Engaged Student Learning Track, this project has created and implemented such a course at three large universities: Texas Tech (a Carnegie high research productivity and Hispanic Serving Institution), Kansas State (a Carnegie high research productivity and land grant university) and California State, Northridge (the largest of all the California State campuses and highly ranked in serving underprivileged students). Our research team includes engineering professors and a sociologist trained in assessment and K-12 outreach to determine the effects of the course on the undergraduate and high school students. We are currently in year two of the three years of NSF support. The course focuses on the fundamentals of the three families of prevailing AM processes: extrusion-based, powder-based, and liquid-based, as well as learning about practical solutions to additive manufacturing of common engineering materials including polymers, metals and alloys, ceramics, and composites. It has a lecturemore »
Creating and Assessing an Upper Division Additive Manufacturing Course and Laboratory to Enhance Undergraduate Research and InnovationThis NSF IUSE project is on the Exploration and Design Tier and the Engaged Student Learning Track. It is aimed at better preparing the country’s professional workforce in the renaissance of U.S. skilled manufacturing by creating new personnel proficient in additive manufacturing (AM). AM is mainstream; it has the potential to bring jobs back to the U.S. and add to the nation’s global competitiveness. AM is the process of joining materials to make objects from 3D data in a layer upon layer fashion. The objectives are to develop, assess, revise, and disseminate an upper division course and laboratory, “Additive Manufacturing,” and to advance undergraduate and K-12 student research and creative inquiry activities as well as faculty expertise at three diverse participating universities: Texas Tech, California State-Northridge, and Kansas State. This research/pedagogical team contains a mechanical engineering professor at each university to develop and teach the course, as well as a sociologist trained in K-12 outreach, course assessment, and human subjects research to accurately determine the effects on K-12 and undergraduate students. The proposed course will cover extrusion-based, liquid-based, and powder-based AM processes. For each technology, fundamentals, applications, and advances will be discussed. Students will learn solutions to AM of polymers,more »