This study introduces multi-objective genetic algorithms for optimizing the stacking sequence of lightweight composite structures. Notably, significant emphasis is placed on adhering to engineering design guidelines specific to stacking sequence design. These guidelines are effectively integrated into the optimization problem formulation as either constraints or additional objectives.
View Article and Find Full Text PDFIn recent years, elastocaloric cooling has shown great potential as an alternative to vapor-compression refrigeration. However, there is still no existing elastocaloric device that offers fatigue-resistant operation and yet high cooling/heat-pumping performance. Here, we introduce a new design of an elastocaloric regenerator based on compression-loaded Ni-Ti tubes, referred to as a shell-and-tube-like elastocaloric regenerator.
View Article and Find Full Text PDFThe interaction of phages with abiotic environmental surfaces is usually an understudied field of phage ecology. In this study, we investigated the virucidal potential of different metal salts, metal and ceramic powders doped with Ag and Cu ions, and newly fabricated ceramic and metal surfaces against Phi6 bacteriophage. The new materials were fabricated by spark plasma sintering (SPS) and/or selective laser melting (SLM) techniques and had different surface free energies and infiltration features.
View Article and Find Full Text PDFIn this work, we combine selective laser melting (SLM) and spark plasma sintering (SPS) to fabricate new materials with high virucidal potential. Various bioactive disc-shaped ceramics, metal alloys, and composites were fabricated and tested against bacteriophage Phi6-a model system for RNA-enveloped viruses. We prepared silver-doped titanium dioxide (TiO + 2.
View Article and Find Full Text PDFElastic materials with holes and inclusions are important in a large variety of contexts ranging from construction material to biological membranes. More recently, they have also been exploited in mechanical metamaterials, where the geometry of highly deformable structures is responsible for their unusual properties, such as negative Poisson's ratio, mechanical cloaking, and tunable phononic band gaps. Understanding how such structures deform in response to applied external loads is thus crucial for designing novel mechanical metamaterials.
View Article and Find Full Text PDFWe present a method for predicting the linear response deformation of finite and semi-infinite 2D solid structures with circular holes and inclusions by employing the analogies with image charges and induction in electrostatics. Charges in electrostatics induce image charges near conductive boundaries and an external electric field induces polarization (dipoles, quadrupoles, and other multipoles) of conductive and dielectric objects. Similarly, charges in elasticity induce image charges near boundaries and external stress induces polarization (quadrupoles and other multipoles) inside holes and inclusions.
View Article and Find Full Text PDFWe present the results of an experimental investigation on the crystallography of the dimpled patterns obtained through wrinkling of a curved elastic system. Our macroscopic samples comprise a thin hemispherical shell bound to an equally curved compliant substrate. Under compression, a crystalline pattern of dimples self-organizes on the surface of the shell.
View Article and Find Full Text PDFPurpose: Percutaneous vertebroplasty is a widely used vertebral augmentation technique. It is a minimally invasive and low-risk procedure, but has some disadvantages with a relatively high number of bone cement leaks and adjacent vertebral fractures. The aim of this cadaveric study was to determine the minimum percentage of cement fill volume in vertebroplasty needed to restore vertebral stiffness and adjacent intradiscal pressure.
View Article and Find Full Text PDFSmart Morphable Surfaces enable switchable and tunable aerodynamic drag reduction of bluff bodies. Their topography, resembling the morphology of golf balls, can be custom-generated through a wrinkling instability on a curved surface. Pneumatic actuation of these patterns results in the control of the drag coefficient of spherical samples by up to a factor of two, over a range of flow conditions.
View Article and Find Full Text PDFKnee Surg Sports Traumatol Arthrosc
May 2013
Purpose: To evaluate the in vitro biomechanical characteristics of patellar tendon ligaments (BTB) when stored as fresh frozen or as glycerol cryopreserved allografts.
Methods: Seventy patellar tendons were harvested from 35 cadaveric human donors and randomly assigned into seven groups. Grafts in group FRESH were mechanically tested within 2 h of harvesting.