Learning mathematical thinking and reasoning is a main goal in mathematical education. Instructional tasks have an important role in fostering this learning. We introduce a learning sequence to approach the topic of integrals in secondary education to support students mathematical reasoning while participating in collaborative dialogue about the integral-as-accumulation-function. This is based on the notion of accumulation in general and the notion of accumulative distance function in particular. Through a case-study methodology we investigate how this approach elicits 11th grade students’ mathematical thinking and reasoning. The results show that the integral-as-accumulation-function has potential, since the notions of accumulation and accumulative function can provide a strong intuition for mathematical reasoning and engage students in mathematical dialogue. Implications of these results for task design and further research are discussed.
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Diminishing motor function is commonly observed in the elderly population and is associated with a wide range of adverse health consequences. Advanced Glycation End products (AGE’s) may contribute to age-related decline in the function of cells and tissues in normal ageing. Although the negative effect of AGE’s on the biomechanical properties of musculoskeletal tissues and the central nervous system have been previously described, the evidence regarding the effect on motor function is fragmented, and a systematic review on this topic is lacking. Therefore, a systematic review was conducted from a total of eight studies describing AGE’s related to physical functioning, physical performance, and musculoskeletal outcome which reveals a positive association between high AGE’s levels and declined walking abilities, inferior ADL, decreased muscle properties (strength, power and mass) and increased physical frailty. Elevated AGE’s levels might be an indication to initiate (early) treatment such as dietary advice, muscle strengthening exercises, and functional training to maintain physical functions. Further longitudinal observational and controlled trial studies are necessary to investigate a causal relationship, and to what extent, high AGE’s levels are a contributing risk factor and potential biomarker for a decline in motor function as a component of ageing process.
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This paper aims to quantify the cumulative damage of unreinforced masonry (URM) subjected to induced seismicity. A numerical model based on discrete element method (DEM) has been develop and was able to represented masonry wall panels with and without openings; which are common typologies of domestic houses in the Groningen gas field in the Netherlands. Within DEM, masonry units were represented as a series of discrete blocks bonded together with zero-thickness interfaces, representing mortar, which can open and close according to the stresses applied on them. Initially, the numerical model has been validated against the experimental data reported in the literature. It was assumed that the bricks would exhibit linear stress-strain behaviour and that opening and slip along the mortar joints would be the predominant failure mechanism. Then, accumulated damage within the seismic response of the masonry walls investigated by means of harmonic load excitations representative of the acceleration time histories recorded during induced seismicity events that occurred in Groningen, the Netherlands.
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Mattresses for the healthcare sector are designed for robust use with a core foam layer and a polyurethane-coated polyester textile cover. Nurses and surgeons indicate that these mattresses are highly uncomfortable to patients because of poor microclimatic management (air, moisture, temperature, friction, pressure regulation, etc) across the mattress, which can cause pressure ulcers (in less than a day). The problem is severe (e.g., extra recovery time, medication, increased risk, and costs) for patients with wounds, infection, pressure-sensitive decubitus. There are around 180,000 waterproof mattresses in the healthcare sector in the Netherlands, of which yearly 40,000 mattresses are discarded. Owing to the rapidly aging population it is expected to increase the demand for these functional mattresses from 180,000 to 400,000 in the next 10 years in the healthcare sector. To achieve a circular economy, Dutch Government aims for a 50% reduction in the use of primary raw materials by 2030. As of January 1, 2022, mattress manufacturers and importers are obliged to pay a waste management contribution. Within the scope of this project, we will design, develop, and test a circular & functional mattress for the healthcare (cure & care) sector. The team of experts from knowledge institutes, SMEs, hospital(s), branch-organization joins hands to design and develop a functional (microclimate management, including ease of use for nurses and patients) mattress that deals with uncomfortable sleeping and addresses the issue of pressure ulcers thereby overall accelerating the healing process. Such development addresses the core issue of circularity. The systematic research with proper demand articulation leads to V-shape verification and validation research methodology. With design focus and applied R&D at TRL-level (4-6) is expected to deliver the validated prototype(s) offering SMEs an opportunity to innovate and expand their market. The knowledge will be used for dissemination and education at Saxion.
Nowadays, there is particular attention towards the recycling of waste materials which is a critical issue for environmental protection and waste management. Polymer materials have numerous applications in daily life products. As a result, plastic pollution has become one of the biggest threats to nature, therefore recycling or replacing them with bio-based materials can significantly help the ecosystems. So far, many studies have investigated the possibility of reusing plastic waste, as a second life, to obtain consumable products. The 3D printing market is one of the great sectors that can utilize a wide range of thermoplastic polymers. This technology provides a unique capability to produce complex shape structures and products that cannot be produced by other manufacturing processes. In particular, Fused Filament Fabrication (FFF) is a common printing technology that consumes thermoplastic filaments including recycled materials. This printing technique has been also very successful in using novel high-performance materials with sustainable aspects. The reSHAPE project aims to develop novel smart filaments, with shape memory properties, from recycled materials. The filaments can be applied for the design and fabrication of smart products with dynamic behavior. In particular, the fabricated parts can shift from a plastic-deformed shape into a recovered original shape when being triggered by an external stimulus, like temperature. For that, we will specifically apply recycled polylactic acid (PLA) and thermoplastic polyurethane (TPU) as the main materials in this study. Because they both have proper shape memory properties and also TPU can potentially enhance the material flexibility which is required in the design and fabrication of functional components. As a result, this study will obtain a proper combination of these materials with good printability and functionality that can be used for a wide range of products from the aerospace and automotive sectors to soft robotics and medical devices.
The application of sensors in water technology is a crucial step to provide broader, more efficient and circular systems. Among the different technologies used in this field, ultrasound-based systems are widely used, basically to generate energy peaks for cell lysis and particle separation. In this work, we propose the adaptation of an ultrasound system to monitor the concentration of solid particles in wastewater treatment plants settlers as well as to indicate sludge level (real time). A similar sensor was developed and tested in another project which operated successfully at solids concentration up to 1% in UASB reactors. Such measurements are nowadays obtained via time-consuming physical (solids) analysis, which can compromise the efficiency of the settlers and the quality of the effluent. The present project proposes an improved version of the sensor, which will combine solids concentration monitoring and sludge level detection. The defined targets have the intention to make a sensor with a much broader range of applications, been suitable not only for UASB reactors but also to settler and aerobic tanks. The project is a cooperation between the Water Technology lectoraat of NHL Stenden University of Applied Sciences, two SME’s - YNOVIO B.V. and Lamp-ion B.V. - and the INCT group (Brazil). If proven feasible, the concept can generate a big business market to the involved Dutch partners as well as favor the automation of WWTP in the Netherlands, Brazil and around the world.
