3D printed geometrically tessellated sheets with origami-inspired patterns

This study demonstrates that the impact energy absorption capabilities of flexible sheets can be significantly enhanced by implementing tessellated designs into their structure. Configurations of three tessellated geometries were tested; they included a triangular-based, a rectangular-based, and a novel square-based pattern. Due to their geometrical complexity, multiple configurations of these tessellations were printed from a rubber-like material using an inkjet printer with two different thicknesses (2 and 4 mm), and their ability to absorb impact energy was compared to an unpatterned inkjet-printed sheet. In addition, the effect of multi-sheets stacking was also tested. Due to the tailored structure, the impact testing showed that the single-layer sheets were more effective at absorbing impact loads, and experience less deformation, than their two-layer counterparts. The 4 mm thick tessellated patterns were most effective at absorbing impact loads; all three thick patterns measured about 40% lower impact forces transferred to the base of the samples compared to the unpatterned counterparts.

NMR-Based Configurational Assignments of Natural Products: Gibbs Sampling and Bayesian Inference Using Floating Chirality Distance Geometry Calculations

Floating chirality restrained distance geometry (fc-rDG) calculations are used to directly evolve structures from NMR data such as NOE-derived intramolecular distances or anisotropic residual dipolar couplings (RDCs). In contrast to evaluating pre-calculated structures against NMR restraints, multiple configurations (diastereomers) and conformations are generated automatically within the experimental limits. In this report, we show that the “unphysical” rDG pseudo energies defined from NMR violations bear statistical significance, which allows assigning probabilities to configurational assignments made that are fully compatible with the method of Bayesian inference. These “diastereomeric differentiabilities” then even become almost independent of the actual values of the force constants used to model the restraints originating from NOE or RDC data.

Resettling Afghan and Iraqi interpreters employed by Western armies: The Contradictions of the Migration–Security Nexus

This article develops a novel analytical framework for capturing the multiple, competing configurations that the migration-security nexus invokes in discourse and practice, combining insights from critical migration and security scholarship. The framework’s application is illustrated with an empirical case study of the protection and relocation of Afghan and Iraqi former local interpreters and other locally employed civilians working for Western armies. The analysis demonstrates that locally employed civilians (LECs) are simultaneously considered security actors in the East and security risks in the West, the ‘best and brightest’ causing brain drain and potential terrorists when crossing borders, both ‘model migrants’ and threats to western values. By uncovering the nexus’s multiple configurations and its contradictions, the framework supports the project of denaturalizing the migration-security nexus, while also showing that the discourses and practices justified through its various configurations include the legitimation of border violence and the denial of protection to migrants.

Real-time bidding campaigns optimization using user profile settings

Real-Time bidding is nowadays one of the most promising systems in the online advertising ecosystem. In the presented study, the performance of RTB campaigns is improved by optimising the parameters of the users’ profiles and the publishers’ websites. Most studies about optimising RTB campaigns are focused on the bidding strategy; estimating the best value for each bid. However, our research is focused on optimising RTB campaigns by finding out configurations that maximise both the number of impressions and the average profitability of the visits. An online campaign configuration generally consists of a set of parameters along with their values such as {Browser = “Chrome”, Country = “Germany”, Age = “20–40” and Gender = “Woman”}. The experiments show that, when the number of required visits by advertisers is low, it is easy to find configurations with high average profitability, but as the required number of visits increases, the average profitability diminishes. Additionally, configuration optimisation has been combined with other interesting strategies to increase, even more, the campaigns’ profitability. In particular, the presented study considers the following complementary strategies to increase profitability: (1) selecting multiple configurations with a small number of visits rather than a unique configuration with a large number of visits, (2) discarding visits according to certain cost and profitability thresholds, (3) analysing a reduced space of the dataset and extrapolating the solution over the whole dataset, and (4) increasing the search space by including solutions below the required number of visits. The developed campaign optimisation methodology could be offered by RTB and other advertising platforms to advertisers to make their campaigns more profitable.

Structures With Multiple Rigid Configurations Due to Prestress and Unilateral Contacts

This paper presents structures with multiple equilibrium configurations arising from the combination of a state of prestress and unilateral contacts. A design problem is posed where preloaded elastic springs and unilateral constraints are embedded throughout a mechanism. The spring parameters are designed such that multiple target configurations are immobilized due to contact. In each of these configurations, the spring forces maintain compressive reaction forces, immobilizing the structure. Each immobilized configuration can rigidly resist perturbation forces up to some finite magnitude where contact is lost. Hence, this case of multiple configurations in equilibrium due to the combination of prestress and contact is referred to as multi-configuration rigidity. Two examples of structures exhibiting multi-configuration rigidity are presented. First, a four bar linkage with a single kinematic degree of freedom is used to introduce the concept. In the context of the linkage, multi-configuration rigidity is compared to multi-stability, exhibiting the key differences between the two concepts. Then, a 24-degree-of-freedom kirigami surface is presented that can morph between flat and spherical configurations, motivated by RF antenna applications. By embedding torsional springs and fold angle stops throughout the structure, flat and spherical configurations are made rigid. Actuation between the configurations can easily be achieved by snapping the structure between the rigid configurations.

AN APPROACH FOR SEMI-AUTOMATIC REDESIGN OF MECHATRONIC PRODUCTS BY MULTIDISCIPLINARY OPTIMISATION

Mechatronic products are widely spread today, but their development still is a challenge. In addition, with the trend of individualisation, not only one solution must be designed but multiple configurations are needed to fulfil customer-specific requirements. To reduce cost and development time, usually existing products are adapted for this purpose. Even though a lot of knowledge is already available through the previous product version, because of multiple disciplines that must be considered in mechatronic systems, even redesign processes are complex. To support the adaption of mechatronic products to changed requirements, an approach to systematically reuse the knowledge available from previous product versions is proposed in this contribution. Through multidisciplinary behaviour optimisation, the solution space is reduced to build an adapted product meeting the new requirements. The approach is explained in detail and illustrated with the example of an electric window regulator and the results are discussed thoroughly.