In recent years, there have been significant advances on materials development for additive manufacturing (AM) applications. However, the use of composites or nanocomposite materials for improved ...performance and multifunctionality are still limited. This review paper attempts to provide a comprehensive review of both commercially available materials as well as research activities related to recent progress on high-performance polymer nanocomposites that are being used in various AM techniques. Four AM techniques including Fused Filament Fabrication (FFF), Selective Laser Sintering (SLS), Multi Jet Fusion (MJF), and Stereolithography (SLA) are discussed. The development of printable polymer composites especially polymer nanocomposites is rapidly expanding the AM materials portfolio, which makes the production of multifunctional parts with complex structures possible.
This study summarizes our current research in using different types of nanographene platelets (NGPs) to create polymer–graphene nanocomposites for selective laser sintering manufacturing application. ...This article describes five NGPs that were available to our research group. Morphological characterization of their microstructures was examined using scanning electron microscopy. Thermal characterization of these NGPs was conducted using thermogravimetric analysis. Kinetics of these NGPs was calculated using the isoconversion technique. Similarities and differences of these NGPs were drawn from the above measurements and calculations. Two NGPs were selected for further studies.
The objective of this study is to develop improved polyamide (nylon) 11 (PA11) and 12 (PA12) polymers with enhanced flame retardancy, thermal, and mechanical properties for selective laser sintering ...rapid manufacturing. PA11 and PA12 were melt-blended, dispersing low concentrations of nanoparticles, namely nanoclays (NCs), carbon nanofibers (CNFs), and nanosilicas (NSs) via twin-screw extrusion. To enhance their thermal and flammability properties, an intumescent flame retardant (FR) was added to the mechanically superior NC and CNF PA11 formulations. NC or CNF additions to either PA11 or PA12 generally increased its tensile strength and modulus, but sharply reduced its elongation at rupture. FR additives reduced PA11’s properties considerably. This substitution, however, only exacerbated the already steep drop in elongation at rupture due to FR additives alone; while elongation dropped 58% with the addition of 30 wt% FR, it dropped 98% with the addition of 25 wt% FR/5 wt% CNF.
Polyamide (nylon) 11 (PA11) and 12 (PA12) were melt-blended, dispersing low concentrations of nanoparticles, namely nanoclays (NCs), carbon nanofibers (CNFs), and nanosilicas (NSs) via twin-screw ...extrusion. To enhance their thermal and flame-retardant (FR) properties, an intumescent FR additive was added to the mechanically superior NC and CNF PA11 formulations. For neat and nanoparticle-reinforced PA11 and PA12, as well as for PA11 reinforced by both intumescent FR and select nanoparticles (NC or CNF), decomposition and heat deflection temperatures were measured, as were the peak heat release rates while burning the composites. All PA11 polymer systems infused with both nanoparticles and FR additive had higher decomposition temperatures than those infused with solely FR additive. For the PA11/FR/NC polymer blends, only the 20 wt% FR and 7.5 wt% clay formulation passed the UL 94 V-0 requirement, while all PA11/FR/ CNF formulations passed UL 94 V-0 requirement.
Polyamide (nylon) 11 (PA11) were melt-blended by dispersing low concentrations of nanoparticles (NPs), namely nanoclays (NCs) and carbon nanofibers (CNFs) via twin-screw extrusion. To enhance their ...thermal and flame retardant (FR) properties, an intumescent FR additive was added to the mechanically superior NC and CNF PA11 formulations. For neat and NP-reinforced PA11 as well as for PA11 reinforced by both intumescent FR and select NPs (NC or CNF), decomposition temperatures by TGA, flammability properties by UL 94, and cone calorimetry values were measured. All PA11 polymer systems infused with both NPs and FR additive had higher decomposition temperatures than those infused with solely FR additive. For the PA11/FR/NC polymer blends, Exolit® OP 1312 (FR2) is the preferred FR additive to pass the UL 94 V-0 requirement with 20 wt%. For the PA11/FR/CNF formulations, all Exolit® OP 1311 (FR1), OP 1312 (FR2), and OP 1230 (FR3) FR additives passed the UL 94 V-0 requirement with 20 wt%.
In the automotive electronic market, sensor conditioning is one of the driving applications. Sensor solutions are pervasive in the vehicle, while signal processing in such application is getting more ...and more complex. Currently the design strategy is often the standard ASIC flow, but the design effort can be reduced by automatic or platform-aided design strategies, or by using software-based solutions. In this paper SensASIP platform is presented. It is a design platform targeting a microprocessor architecture enhanced by dedicated instructions for computing intensive sensor signal processing tasks. SensASIP allows a seamless design flow from MATLAB-based algorithm definition and instruction set design and simulation, down to hardware macrocell HDL description and implementation in CMOS technology. SensASIP features are described through two automotive sensor conditioning examples. Special focus is put on its increased flexibility and reduced design-effort vs. standard ASIC design approach and on its low complexity overhead vs. other state-of-art software-based solutions.
Purpose: Equestrian sports are known to have a high risk and rate of injury. While there is injury data available on acute injuries in the equestrian population, it is of a general nature. Within ...that data appears to be a lack of information on the collegiate equestrian athlete. Thus, the purpose of the current study and this analysis is to describe the incidence of upper and lower extremity injuries and head injuries, sans concussion, in intercollegiate equestrian athlete. Method: A survey was developed with input from each author and implemented in Mach forms. It was sent to 43 equestrian coaches in the Eastern United States who passed it on to their athletes. We estimated 753 athletes would have access to the survey and had a total of 73 respondents. Descriptive statistics were calculated for total number of injuries for each injury category. Results: Detailed injury information on the upper and lower extremity and head is found in tables 1-10. The upper and lower extremity and head accounted for 15.97, 60.35 and 4.33 percent respectively of the injuries in this group of athletes.Conclusions and Recommendations:The current study is amongst the first, if not the first, to report specifically on injury patterns and frequency in US collegiate equestrian athletes. The data indicate that there is an extremely high incidence of injury in the collegiate equestrian population. The lower extremity is particularly susceptible to injury in the equestrian athletes. The lack of data available in a sport, which can be classified as collision and has the potential for significant, long-standing disability from an early age due to interaction with the horse, is troubling. Significantly more sport specific research is needed to improve the health and safety of these athletes.
Purpose: Equestrian sports are known to have a high risk and rate of injury. While there is injury data available on acute injuries in the equestrian population, it is of a general nature. Within ...that data appears to be a lack of information on the collegiate equestrian athlete. Thus, the purpose of the current study and this analysis is to describe the demographics and incidence of spinal injuries found in intercollegiate equestrian athlete. Method: A survey was developed with input from each author and implemented in Mach forms. It was sent to 43 equestrian coaches in the Eastern United States who passed it on to their athletes. We estimated 753 athletes would have access to the survey and had a total of 73 respondents. Descriptive statistics were calculated for total number of injuries for each injury category. Results: Demographic information, conditioning activity, riding style, pain medication use, total responses (injuries) per body area and injuries to the spine and pelvis are detailed in tables 1-6. Of interesting note is only 73% of respondents reported having access to or utilizing the schools athletic program as part of their participation on the schools equestrian team. Conclusions and Recommendations: The current study is amongst the first, if not the first, to report specifically on injury patterns and frequency in US collegiate equestrian athletes. There were several findings that from a sports medicine and athletic perspective are concerning. The lack of overall knowledge and research about the equestrian athlete would appear to put it in the same position as cheerleading was 20 years ago. Significantly more sport specific research is needed to improve the health and safety of the athletes.
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