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ABSTRACT: Hydropower with a small elevation change from inlet to outlet, known as “low-head” hydropower, is a relatively untapped resource for reliable green power generation. One major barrier to entry is the cost of the components needed to generate the power. Each installation site is unique, with various head levels, flow rates, and other unique site characteristics that drive up the cost of development and installation. As a result, custom-made components are necessary because the sites are intrinsically inefficient. However, customized parts are generally more expensive to manufacture than ready-made parts. Often times, the cost of custom-made components is so high that the low-head hydropower installation becomes non-viable. Additive manufacturing offers the ability to make custom components, ideal for one-off applications, at low costs that are well suited for the needs of low-head hydropower. Indirect additive manufacturing, such as making tools or dies rather than end use components, can also be used to make low-cost composite tooling as needed for these custom applications. This paper explores the use of additive manufacturing, both directly and indirectly, to produce the components of a turbine system for a low-head hydropower site. The parts were designed to form a unique modular system, which saves time for future designs and iterations. The system has operated for more than three years without failure at a test site in Wisconsin, USA. This work serves as a basis for future application of AM to low-head systems, in which the modular components can be customized for each unique hydropower installation.

Computer-aided manufacturing (CAM) techniques for hybrid manufacturing have led to new application areas in the manufacturing industry. In the tooling industry, cooling channels are used to enable specific heating and cooling cycles to improve the performance of the process. These internal cooling channels have been designed with limited manufacturing processes in mind, so, until recently, they were often straight in shape for cross-drilling operations and manufactured from a cast billet. To show a novel application of this common technology, a tool with integrated conformal cooling channels was manufactured using hybrid manufacturing (blown-powder DED and CNC machining) techniques. The computer-aided manufacturing strategy used, and the lessons learned are presented and discussed to enable future work in this industrial application space.

At the onset of the COVID-19 (Coronavirus Disease 2019) pandemic, USA faced supply chain issues causing a nationwide shortage of N95 respirators and PAPR devices. Researchers at Oak Ridge National Laboratory's (ORNL) Manufacturing Demonstration Facility (MDF) were sent to work from home to help slow the spread of the pandemic, and during that time they were tasked with using their manufacturing expertise to research alternative methods of producing face masks. To rapidly iterate on face mask designs without access to a research or manufacturing facility, 3D (3-Dimensional) printing and silicone casting were used. Molds and components for the masks are modeled with computer-aided design (CAD), printed with common home desktop 3D printers, and test poured with skin-safe silicone rubber. The resultant masks are form fitting and comfortable to wear. To ease the shortage of N95 filter media, the masks are designed to use existing filter materials such as home HVAC (heating, ventilation, and air conditioning) filters. The masks can be sanitized, and the filter replaced to allow the same mask to be reused. The result is not equivalent to an N95 mask, and not meant to be a replacement, but is meant to be a stopgap mask that is still able to provide the wearer filtered protection. Filtration testing has not been performed because it is not the intention of the authors to make medical claims. This research is meant to demonstrate the rapid design, iteration, and manufacturing processes of a stopgap mask.

The susceptibility of groups A, C, and G streptococci isolated from pharynx or skin in two northern Canadian native communities during a one year study of the epidemiology of streptococcal infection was determined for penicillin, erythromycin and clindamycin using an agar dilution method. Organisms studied included 725 group A, 82 group C, and 184 group G streptococci. All organisms were susceptible to penicillin (minimum inhibitory concentration [MIC] range less than 0.004 to 0.015 μg/mL; MIC90 0.015 μg/mL) and clindamycin (range 0.007 to 0.06 μg/mL; MIC90 0.06 μg/mL) with no differences observed between streptococcal groups. For erythromycin, groups A and C were generally susceptible (range less than 0.007 to 0.030 μg/mL; MIC90 0.03 μg/mL; and range 0.007 to 1.0 μg/mL; MIC90 0.06 μg/mL, respectively). Group G was less susceptible (range 0.007 to greater than 2.0 μg/mL; MIC90 greater than 2.0 μg/mL) with 38% of all isolates having an MIC greater than or equal to 1 μg/mL. On review of group G isolates, 100 of 100 from one community were susceptible (MIC less than 0.007 to 0.03 μg/mL) and 73 (87%) of 84 from the second community were resistant. All resistant strains tested were type T16. These data suggest that erythromycin-resistant group G streptococci may occur with high prevalence in certain populations and that patterns of antimicrobial susceptibility in isolated communities may be highly community-specific.