MXenes. In their Research Article (e202314638), Li Ding, Jürgen Caro, Haihui Wang et al. report a 2D MXene membrane with super‐aligned nanochannels by applying shear forces to a liquid‐crystalline ...MXene nanosheet dispersion.
MXenes. In their Research Article (e202314638), Li Ding, Jürgen Caro, Haihui Wang et al. report a 2D MXene membrane with super‐aligned nanochannels by applying shear forces to a liquid‐crystalline ...MXene nanosheet dispersion.
The distributions of pressure and shear forces inside the proton are investigated using lattice quantum chromodynamics (LQCD) calculations of the energy momentum tensor, allowing the first ...model-independent determination of these fundamental aspects of proton structure. This is achieved by combining recent LQCD results for the gluon contributions to the energy momentum tensor with earlier calculations of the quark contributions. The utility of LQCD calculations in exploring, and supplementing, the assumptions in a recent extraction of the pressure distribution in the proton from deeply virtual Compton scattering is also discussed. Based on this study, the target kinematics for experiments aiming to determine the pressure and shear distributions with greater precision at Thomas Jefferson National Accelerator Facility and a future electron ion collider are investigated.
Inspired by the human skin, electronic skins (e‐skins) composed of various flexible sensors, such as strain sensor, pressure sensor, shear force sensor, temperature sensor, and humility sensor, and ...delicate circuits, are emerged to mimic the sensing functions of human skins. In this review, the strategies to realize the versatile functionalities of natural skin‐like e‐skins, including strain‐, pressure‐, shear force‐, temperature‐ and humility‐sensing abilities, as well as self‐healing ability and other functions are summarized. Some representative examples of high‐performance e‐skins and their applications are outlined and discussed. Finally, the outlook of the future of e‐skins is presented.
Electronic skin is a type of soft electric device that possesses various sensing capabilities like the human skin. In this review, the strategies to realize the versatile functionalities of e‐skin, including strain‐, pressure‐, shear force‐, temperature‐ and humility‐sensing abilities, as well as self‐healing ability and other functions are summarized.
Confined masonry (CM) buildings are generally designed with an expectation that masonry walls withstand all possible loads imparted on the buildings. The reinforced concrete (RC) confining members, ...also known as tie-members, have the sole purpose of constraining the masonry and avoiding its outward spread during lateral earthquake loading. Reliable design rules for tie-columns are scarce in design codes of CM structures, often resulting in the nominal design of tie-elements without considering the influence of all the important parameters related to the material and geometric properties of CM wall. This often results in the construction of weaker tie-members, especially the tie-columns, that can lead to their direct failure and the failure of the entire wall during earthquakes. To address this issue, a methodology was developed for assessing the design shear forces for the tie-columns as well as masonry subjected to lateral loading by utilizing the past observations from systematic experimental and numerical studies. The efficacy of this methodology was evaluated in the present experimental study conducted on CM walls with varying aspect ratios. The test results demonstrated that the proposed methodology can result in a significant improvement in the lateral load behavior of CM walls, by delaying the shear failure of tie-columns without jeopardizing other functional requirements.
Sensing of the interaction forces at fingertips is of great value in assessment and rehabilitation therapy. Current force sensors are not compliant to the fingertip tissue and result in loss of touch ...sensation of the user. This work shows the development and characterization of a flexible fully-3D-printed piezoresistive shear and normal force sensor that uses the mechanical deformation of the finger tissue. Two prototypes of the sensing structure are evaluated using a finite element model and a measurement setup that applies normal and shear forces up to 10 N on a fingertip phantom placed inside the sensing structure, which is fixed to prevent slippage. Furthermore, the relation between strain (rate) and resistance of the conductive TPU, used for the strain gauges, is characterized. The applied normal and shear force components of the 3D-printed sensing structure can be partly separated. FEM analysis showed that the output of the sensor is largely related to the sensor geometry and location of the strain gauges. Furthermore, the conductive TPU that was used has a negative gauge factor for the strain range used in this study and might cause non-linear behaviors in the sensor output.
Advances in engineering hydrogels Zhang, Yu Shrike; Khademhosseini, Ali
Science (American Association for the Advancement of Science),
05/2017, Letnik:
356, Številka:
6337
Journal Article
Recenzirano
Odprti dostop
Hydrogels are formed from hydrophilic polymer chains surrounded by a water-rich environment. They have widespread applications in various fields such as biomedicine, soft electronics, sensors, and ...actuators. Conventional hydrogels usually possess limited mechanical strength and are prone to permanent breakage. Further, the lack of dynamic cues and structural complexity within the hydrogels has limited their functions. Recent developments include engineering hydrogels that possess improved physicochemical properties, ranging from designs of innovative chemistries and compositions to integration of dynamic modulation and sophisticated architectures. We review major advances in designing and engineering hydrogels and strategies targeting precise manipulation of their properties across multiple scales.
Slippery and hydrophilic surfaces find critical applications in areas as diverse as biomedical devices, microfluidics, antifouling, and underwater robots. Existing methods to achieve such surfaces ...rely mostly on grafting hydrophilic polymer brushes or coating hydrogel layers, but these methods suffer from several limitations. Grafted polymer brushes are prone to damage and do not provide sufficient mechanical compliance due to their nanometer‐scale thickness. Hydrogel coatings are applicable only for relatively simple geometries, precluding their use for the surfaces with complex geometries and features. Here, a new method is proposed to interpenetrate hydrophilic polymers into the surface of diverse polymers with arbitrary shapes to form naturally integrated “hydrogel skins.” The hydrogel skins exhibit tissue‐like softness (Young's modulus ≈ 30 kPa), have uniform and tunable thickness in the range of 5–25 µm, and can withstand prolonged shearing forces with no measurable damage. The hydrogel skins also provide superior low‐friction, antifouling, and ionically conductive surfaces to the polymer substrates without compromising their original mechanical properties and geometry. Applications of the hydrogel skins on inner and outer surfaces of various practical polymer devices including medical tubing, Foley catheters, cardiac pacemaker leads, and soft robots on massive scales are further demonstrated.
Multifunctional hydrogel skins by interpenetrating hydrophilic polymers into the surfaces of diverse polymers with arbitrary shapes, which provide soft, low‐friction, hydrophilic, antifouling, and ionically conductive surfaces, are reported. This new strategy not only addresses challenges for existing methods but also enables unprecedented applications including hydrogel‐coated complex medical devices and soft robots on massive scales.
•A significant amount of nanoplastics is being released from rinsed-off products.•Water shear forces induce nanoplastics generation from microplastics fragmentation.•Living organisms can indirectly ...ingest nanoplastics by diffusion through their skin.
The presence of nanoplastics in water has become a major environmental concern in the last decade however the knowledge on the origin and formation of these emerging contaminants is lacking due to analytical challenges in detection and quantification techniques. The release of nanoplastics due to the fragmentation of microplastics extracted from a facial scrub and the resulting toxicity on aquatic species are reported here for the first time. The daily use of 4 g of facial scrub could release up to 1011 microplastics of 400 nm in size per litre of wastewater from household drains. Turbulences created by mixing or pumping induced the fragmentation of microplastics into nanoplastics smaller than 10 nm via a crack propagation and failure mechanism, increasing the number of particles in water by one order of magnitude. Compared to microplastics at a fixed concentration number of 6.8 × 108 part./mL, the generated nanoplastics initiated the death of 54% more cells in zebrafish by passive ingestion via skin diffusion which therefore pose a real threat for aquatic living organisms. These results stress the need to reduce the release of nano/microplastics in the aquatic environment to prevent the contamination of all trophic levels.
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