Solid Freeform Fabrication Research In Engineering Education

Because Solid Freeform Fabrication (SFF) has an extremely wide range of potential applications, crossing traditional engineering and science boundaries, it is a technology that lends itself to multi-disciplinary activities and projects. SFF is an ideal mechanism to present scientific concepts including materials science and mechanics, as well as larger-scope engineering topics such as agile manufacturing. At Milwaukee School of Engineering (MSOE), we are using SFF technologies as a means to teach engineering concepts to undergraduate students through multidisciplinary research. MSOE was awarded a five-year grant under the NSF Research Experiences for Undergraduates Program (EEC-9619715) to facilitate student exploration in the field of Solid Freeform Fabrication. Sixty undergraduates will participate in summer and academic year programs by the year 2001. Eighteen students from around the country have participated in the program to date, bringing with them a diverse background of university experience, skill level, and interests. Working closely with a faculty advisor possessing expertise in a particular research area, they have performed research on Solid Freeform Fabrication applications in the biomedical, aerospace, architectural, manufacturing, and electronics industries. Some ofthe keys to the success of this program include: • Hands-on access to Solid Freeform Fabrication equipment through the facilities ofthe MSOE Rapid Prototyping Center (SLA 250, LOM 2030, and FDM 1650). • Close partnerships of the students with faculty and industry mentors in specialized areas of expertise. • Teaming with other educational institutions. • Significant cross-pollination between projects; faculty from diverse departments. • Encouraging students to publish and present results at national conferences and symposia.Mechanical Engineerin

Predicting and Controlling Resolution and Surface Finish of Ceramic Objects Produced by Stereodeposition Processes

Stereodeposition techniques are well suited for the Solid Freeform Fabrication of dense ceramic components. As opposed to forming a pattern in a particle bed or polymer bath, stereodeposition processes deposit material directly onto the previously created layer. The key to stereodeposition is a material's ability to be dispensed as a fluid, yet rapidly stiffen to hold the shape of the object. This is accomplished by either solidification of a thermoplastic binder upon cooling from a melt (Fused Deposition) or by polymerization of a binder (Reactive Stereodeposition). We are developing both techniques for the production of functional ceramic and engineering polymer objects. A key issue in developing a successful stereodeposition system is controlling the rate of bead transformation from liquid to solid. Control is critical to achieving high resolution and low surface roughness of the finished product, but is made complex by the large number of parameters involved. These include binder parameters (surface tension, gelling characteristics), slurry parameters (viscosity, particle loading and size distribution), and process parameters (deposition rate, temperature). Current efforts at the University of Arizona are focused on modeling and controlling the deposition and transformation of ceramic slurries used in the Reactive Stereodeposition process.Mechanical Engineerin

Complications Associated With Anesthesia Services in Endoscopic Procedures Among Patients With Cirrhosis

Background and Aims: Anesthesia services for endoscopic procedures have proliferated with the promise of increased comfort and safety. Cirrhosis patients are higher risk for sedation, yet limited data are available describing anesthesia complications in this population. Approach and Results: This cross-sectional study utilized the National Anesthesia Clinical Outcomes Registry, a multicenter quality-improvement database from 2010 to 2015. Patients with cirrhosis undergoing an endoscopy were identified by International Classification of Diseases, Ninth Revision (ICD-9)/Current Procedures Terminology (CPT) codes. The outcome of interest was serious anesthesia-related complication defined as cardiovascular, respiratory, neurological, drug related, patient injury, death, or unexpected admission. A mixed-effects multivariate logistic regression model determined odds ratios (ORs) between variables and serious complications, adjusting for potential confounders. In total, 9,007 endoscopic procedures were performed among patients with cirrhosis; 92% were esophagogastroduodenoscopies. The majority (81%) were American Society of Anesthesiologists (ASA) class ≥3, and 72% had a history of hepatic encephalopathy, ascites, varices, hepatorenal syndrome, or spontaneous bacterial peritonitis identified by ICD-9/CPT codes. In total, 87 complications were reported, 33 of which were serious. Frequency of serious complications was 0.4% or 378.6 per 100,000 procedures (95% confidence interval [CI], 260.8, 531.3). The majority of serious complications were cardiovascular (21 of 33), including 15 cardiac arrests. Serious complications were significantly associated with ASA 4/5 (OR, 3.84; 95% CI, 1.09, 13.57) and general anesthesia (OR, 4.71; 95% CI, 1.20, 18.50), adjusting for age, sex, ASA class, anesthesia type, inpatient status, portal hypertension history, and variable complication reporting practices. Conclusions: Anesthesia complications among endoscopic procedures in cirrhosis are rare overall. Serious complications were predominantly cardiac and associated with sicker patients undergoing general anesthesia. The complexity of end-stage liver disease may warrant more intensive care during endoscopic procedures, including anesthesia monitoring

The Liquid-to-Solid Transition in Stereodeposition Techniques

Mechanical Engineerin

Composites with Gradient Properties From Solid Freeform Fabrication

TetraCast is a build style developed by Milwaukee School ofEngineering involving stereolithography patterns produced with an open cellular structure inside a surface shell. Composites are created using this pattern as a host fora filler material, generally epoxy matrices loaded with various fibers or microspheres. Regions within a singleobjectrrray be separated by thin barriers, allowing filling with different matrix materials.to create regiollsof differing.local properties. The internal structure can also be continually graded in thickness to prodUl::e composites with properties ranging from that ofthe fillermaterial to that ofthe TetraCast material (currently stereolithography epoxy or FDM ABS)Mechanical Engineerin

One-year multicenter, double-masked, placebo-controlled, parallel safety and efficacy study of 2% pirenzepine ophthalmic gel in children with myopia

10.1016/j.ophtha.2004.06.038Ophthalmology112184-91OPHT