158 research outputs found

    3D Printing of a Photo-thermal Self-folding Actuator

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    The demand for rapid and accurate fabrication of light-weight, biocompatible, and soft actuators in soft robotics has perused researchers to design and fabricate such products by rapid manufacturing techniques. The self-folding origami structure is a type of soft actuator that has applications in micro electro mechanical systems, soft electronics, and biomedical devices. 3-dimentional (3D) printing is a current manufacturing process that can be used for fabrication of involute soft self-folding products by means of shape memory polymer materials. This paper presents, for the first time, a method for developing a photo thermal self-folding soft actuator using a 3D bioplotter. Easily accessible and inexpensive pre-strained polystyrene is opted for the backbone of actuator. The polystyrene film (PS) is then structured in a hand shape gripper. Chitosan hydrogel and carbon black ink were combined for printing active hinges on the hand gripper. Various active hinges with different widths and thicknesses were printed on the hand gripper using the 3D bioplotter. An infra-red (IR) heating lamp was placed at a reasonable distance to emit IR light uniformly on the hand gripper. The temperature distribution on the hand gripper was observed using a thermographic camera and the bending angles of the samples were recorded by a video camera. It was observed that the bending angles of the hand fingers depend on factors such as the intensity of the heat flux generated by the IR light intensity, distance, onset temperature, geometry of the fingers such as width and thickness, and area of the hinges

    Surface nanogrooving of carbon microtubes

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    Extrusion processing of carbon tubes can be problematic due to their poor interfacial interactions with polymeric matrices. Surface chemical modification of carbon tubes can be utilized to create bonding sites to form networks with polymer chains. However, chemical reactions resulting in intermolecular primary bonding limit processability of extrudate, since they cause unstable rheological behaviour, and thus decrease the stock holding time, which is determinative in extrusion. This study presents a method for the synthesis of carbon microtubes with physically modified surface area to improve the filler and matrix interfacial interactions. The key concept is the formation of a nanogrooved topography, through acoustic cavitation on the surface of processing fibres. The effect of nanogrooving on roughness parameters is described, along with the role of surface modified carbon tubes on rheological behaviour, homogeneity, and coherency of extrudate. The measurements showed that nanogrooving increases the surface area of carbon microtubes, as a result, die swelling of the extrudate is reduced. Furthermore, after solidification, the mechanical strength of composite is reinforced due to stronger interactions between nanogrooved carbon tubes and polymer matrix

    Incident type 2 diabetes attributable to suboptimal diet in 184 countries

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    The global burden of diet-attributable type 2 diabetes (T2D) is not well established. This risk assessment model estimated T2D incidence among adults attributable to direct and body weight-mediated effects of 11 dietary factors in 184 countries in 1990 and 2018. In 2018, suboptimal intake of these dietary factors was estimated to be attributable to 14.1 million (95% uncertainty interval (UI), 13.814.4 million) incident T2D cases, representing 70.3% (68.871.8%) of new cases globally. Largest T2D burdens were attributable to insufficient whole-grain intake (26.1% (25.027.1%)), excess refined rice and wheat intake (24.6% (22.327.2%)) and excess processed meat intake (20.3% (18.323.5%)). Across regions, highest proportional burdens were in central and eastern Europe and central Asia (85.6% (83.487.7%)) and Latin America and the Caribbean (81.8% (80.183.4%)); and lowest proportional burdens were in South Asia (55.4% (52.160.7%)). Proportions of diet-attributable T2D were generally larger in men than in women and were inversely correlated with age. Diet-attributable T2D was generally larger among urban versus rural residents and higher versus lower educated individuals, except in high-income countries, central and eastern Europe and central Asia, where burdens were larger in rural residents and in lower educated individuals. Compared with 1990, global diet-attributable T2D increased by 2.6 absolute percentage points (8.6 million more cases) in 2018, with variation in these trends by world region and dietary factor. These findings inform nutritional priorities and clinical and public health planning to improve dietary quality and reduce T2D globally. (c) 2023, The Author(s)

    Children's and adolescents' rising animal-source food intakes in 1990-2018 were impacted by age, region, parental education and urbanicity

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    Animal-source foods (ASF) provide nutrition for children and adolescents physical and cognitive development. Here, we use data from the Global Dietary Database and Bayesian hierarchical models to quantify global, regional and national ASF intakes between 1990 and 2018 by age group across 185 countries, representing 93% of the worlds child population. Mean ASF intake was 1.9 servings per day, representing 16% of children consuming at least three daily servings. Intake was similar between boys and girls, but higher among urban children with educated parents. Consumption varied by age from 0.6 at <1 year to 2.5 servings per day at 1519 years. Between 1990 and 2018, mean ASF intake increased by 0.5 servings per week, with increases in all regions except sub-Saharan Africa. In 2018, total ASF consumption was highest in Russia, Brazil, Mexico and Turkey, and lowest in Uganda, India, Kenya and Bangladesh. These findings can inform policy to address malnutrition through targeted ASF consumption programmes. (c) 2023, The Author(s)
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