Optimizing 3D concrete printing: exploring potentials and limitations of materials and production

The application of new Computer Aided Manufacturing (CAM), digital fabrication and additive manufacturing techniques in the construction industries is expected to bring major change to these industries. Driven by a foreseen reduction of construction time and labor cost, simplification of logistics and an increase of constructible geometrical freedom, many experiments are performed both at academia and in practice. Beyond these economical and architectural objectives, digital fabrication in construction can be used to reduce the environmental footprint of the industry. The increased level of control offered by digital fabrication enables the use of advanced computational optimisation techniques. With these optimisation techniques buildings can be designed which, for instance, combine an optimal thermal performance with a minimum use of materials, while still complying with all codes and standards. In order to fully utilise this potential of digital fabrication, the capabilities and limitations of the manufacturing process need to be taken into account during optimisation. By combining the concrete 3D printing knowledge of Eindhoven University of Technology, the optimisation expertise of the BEMNext lab at Delft University of Technology and software development by White Lioness technologies, the ‘Optimising 3D concrete printing’ Lighthouse project has made the first steps towards more knowledge on integrated optimisation and manufacturing

Optimizing 3D concrete printing: exploring potentials and limitations of materials and production

The application of new Computer Aided Manufacturing (CAM), digital fabrication and additive manufacturing techniques in the construction industries is expected to bring major change to these industries. Driven by a foreseen reduction of construction time and labor cost, simplification of logistics and an increase of constructible geometrical freedom, many experiments are performed both at academia and in practice. Beyond these economical and architectural objectives, digital fabrication in construction can be used to reduce the environmental footprint of the industry. The increased level of control offered by digital fabrication enables the use of advanced computational optimisation techniques. With these optimisation techniques buildings can be designed which, for instance, combine an optimal thermal performance with a minimum use of materials, while still complying with all codes and standards. In order to fully utilise this potential of digital fabrication, the capabilities and limitations of the manufacturing process need to be taken into account during optimisation. By combining the concrete 3D printing knowledge of Eindhoven University of Technology, the optimisation expertise of the BEMNext lab at Delft University of Technology and software development by White Lioness technologies, the ‘Optimising 3D concrete printing’ Lighthouse project has made the first steps towards more knowledge on integrated optimisation and manufacturing

Feasibility of a Knowledge-Based Engineering framework for the AEC industries

This paper presents the development of a novel computational framework with which expert analysis knowledge can be captured, stored and dynamically retrieved when required to determine the performance of a building design with respect to user-defined requirements. By subdividing the engineer's and designer's knowledge into discrete steps, and storing these steps in a database along with a description of the context in which the knowledge is to be applied, a searchable knowledge base is created. Given a context consisting of a BIM model and one or more building requirements for which metrics are to be provided, the applicable knowledge can be iteratively retrieved from the knowledge base. Through computational reasoning an analysis is acquired as a chain of logically connected analysis steps. Foreseen benefits of use of the framework include safekeeping and disclosure of AEC expert's knowledge and automation of analyses without loss of analysis transparency.Steel & Composite StructuresApplied Mechanic

Optimising 3D printed concrete structures using topology optimisation

\u3cp\u3eAdditive manufacturing and 3D printing are rapidly developing digital fabrication techniques (Lu et al. 2015). After the first steps in small scale printing of metals (Frazier 2014) and plastics (Gibson et al. 2014) have been made, research from various groups around the world is now also focusing on large scale printing in concrete (Lim et al. 2012) and making this technology more suitable for the construction scale. The potential of using this technology is that it will be possible to create complex and/or customised concrete designs with the expectation that the costs will be low and the construction speeds will be high. Additionally, this new technology will provide opportunities to create more efficient structures. Structures can already be optimised in the early stages of the design for weight and structural performance, but the resulting optimised structures are often difficult to manufacture due to the resulting geometry of the design. Additive manufacturing can address this issue without high costs for moulds and labour. This paper will present a novel methodology to include material performance and manufacturing constraints of 3D printed concrete in design optimisation processes. The study examines the possibility to optimise concrete structures in the design phase. In order to save material and thus create more sustainable and more cost efficient structures, a topology optimisation method has been created specifically for 3D printed concrete. Traditional topology optimisation methods consider isotropic and linear elastic material and will not necessarily produce realisable and reliable optimised structures. In the algorithm presented constraints of the printing process and material properties from physical testing of this layered material have been considered in the optimisation. By adopting this methodology more realistic and feasible optimal concrete structures can be designed.\u3c/p\u3

Differential effects of a 40-hour fast and bile acid supplementation on human GLP-1 and FGF19 responses

Bile acids, glucagon-like peptide-1 (GLP-1). and fibroblast growth factor 19 (FGF19) play an important role in postprandial metabolism. In this study, we investigated the postprandial bile acid response in plasma and its relation to insulin, GLP-1, and FGF19. First, we investigated the postprandial response to 40-h fast. Then we administered glycine-conjugated deoxycholic acid (gDCA) with the meal. We performed two separate observational randomized crossover studies on healthy. lean men. In experiment 1: we tested 4-h mixed meal after an overnight fast and a 40-h fast. In experiment 2, we tested a 4-h mixed meal test with and without gDCA supplementation. Both studies measured postprandial glucose, insulin, bile acids. GLP-1, and FGF19. In experiment 1, 40 h of fasting induced insulin resistance and increased postprandial GLP-1 and FGF19 concentrations. After an overnight fast, we observed strong correlations between postprandial insulin and gDCA levels at specific time points. In experiment 2, administration of gDCA increased GLP-1 levels and lowered late postprandial glucose without effect on FGF19. Energy expenditure was not affected by gDCA administration. Unexpectedly. 40 h of fasting increased both GLP-1 and FGF19, where the former appeared bile acid independent and the latter bile acid dependent. Second, a single dose of gDCA increased postprandial GLP-1. Therefore, our data add complexity to the physiological regulation of the enterokines GLP-1 and FGF19 by bile acids

Rapid stromal remodeling by short-term VEGFR2 inhibition increases chemotherapy delivery in esophagogastric adenocarcinoma

Anti-angiogenic agents combined with chemotherapy is an important strategy for the treatment of solid tumors. However, survival benefit is limited, urging the improvement of combination therapies. We aimed to clarify the effects of vascular endothelial growth factor receptor 2 (VEGFR2) targeting on hemodynamic function and penetration of drugs in esophagogastric adenocarcinoma (EAC). Patient-derived xenograft (PDX) models of EAC were subjected to long-term and short-term treatment with anti-VEGFR2 therapy followed by chemotherapy injection or multi-agent dynamic contrast-enhanced (DCE-) MRI and vascular casting. Long-term anti-VEGFR2-treated tumors showed a relatively lower flow and vessel density resulting in reduced chemotherapy uptake. On the contrary, short-term VEGFR2 targeting resulted in relatively higher flow, rapid vasodilation, and improved chemotherapy delivery. Assessment of the extracellular matrix (ECM) revealed that short-term anti-angiogenic treatment drastically remodels the tumor stroma by inducing nitric oxide synthesis and hyaluronan degradation, thereby dilating the vasculature and improving intratumoral chemotherapy delivery. These previously unrecognized beneficial effects could not be maintained by long-term VEGFR2 inhibition. As the identified mechanisms are targetable, they offer direct options to enhance the treatment efficacy of anti-angiogenic therapy combined with chemotherapy in EAC patients