scholarly journals Diversifying Composition Leads to Hierarchical Composites with Design Flexibility and Structural Fidelity

ACS Nano ◽  
2021 ◽  
Author(s):  
Le Ma ◽  
Hejin Huang ◽  
Emma Vargo ◽  
Jingyu Huang ◽  
Christopher L. Anderson ◽  
...  
Keyword(s):  
Design Flexibility ◽  
Hierarchical Composites

scholarly journals Vanadium Redox Flow Batteries: A Review Oriented to Fluid-Dynamic Optimization

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 176
Author(s):  
Iñigo Aramendia ◽  
Unai Fernandez-Gamiz ◽  
Adrian Martinez-San-Vicente ◽  
Ekaitz Zulueta ◽  
Jose Manuel Lopez-Guede
Keyword(s):  
Large Scale ◽  
Numerical Models ◽  
Fluid Dynamic ◽  
Renewable Energy Sources ◽  
Vanadium Redox Flow Battery ◽  
Redox Flow Batteries ◽  
Design Flexibility ◽  
Flow Batteries ◽  
Exchange Membrane ◽  
Vanadium Redox

Large-scale energy storage systems (ESS) are nowadays growing in popularity due to the increase in the energy production by renewable energy sources, which in general have a random intermittent nature. Currently, several redox flow batteries have been presented as an alternative of the classical ESS; the scalability, design flexibility and long life cycle of the vanadium redox flow battery (VRFB) have made it to stand out. In a VRFB cell, which consists of two electrodes and an ion exchange membrane, the electrolyte flows through the electrodes where the electrochemical reactions take place. Computational Fluid Dynamics (CFD) simulations are a very powerful tool to develop feasible numerical models to enhance the performance and lifetime of VRFBs. This review aims to present and discuss the numerical models developed in this field and, particularly, to analyze different types of flow fields and patterns that can be found in the literature. The numerical studies presented in this review are a helpful tool to evaluate several key parameters important to optimize the energy systems based on redox flow technologies.

scholarly journals Expanding 3D Nanoprinting Performance by Blurring the Electron Beam

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 115
Author(s):  
Lukas Seewald ◽  
Robert Winkler ◽  
Gerald Kothleitner ◽  
Harald Plank
Keyword(s):  
Electron Beam ◽  
Direct Write ◽  
Design Flexibility ◽  
Individual Branch ◽  
Inclination Angles ◽  
3D Architecture ◽  
20 Nm ◽  
Surface Morphologies ◽  
Nm Range ◽  
Mechanical Rigidity

Additive, direct-write manufacturing via a focused electron beam has evolved into a reliable 3D nanoprinting technology in recent years. Aside from low demands on substrate materials and surface morphologies, this technology allows the fabrication of freestanding, 3D architectures with feature sizes down to the sub-20 nm range. While indispensably needed for some concepts (e.g., 3D nano-plasmonics), the final applications can also be limited due to low mechanical rigidity, and thermal- or electric conductivities. To optimize these properties, without changing the overall 3D architecture, a controlled method for tuning individual branch diameters is desirable. Following this motivation, here, we introduce on-purpose beam blurring for controlled upward scaling and study the behavior at different inclination angles. The study reveals a massive boost in growth efficiencies up to a factor of five and the strong delay of unwanted proximal growth. In doing so, this work expands the design flexibility of this technology.

Smart DRA for beam width and orientation control

Frequenz ◽  
2020 ◽  
Vol 74 (11-12) ◽  
pp. 383-392
Author(s):  
Rajveer S. Yaduvanshi ◽  
Richa Gupta ◽  
Saurabh Katiyar
Keyword(s):  
Radiation Pattern ◽  
High Efficiency ◽  
Beam Width ◽  
Beam Control ◽  
Design Flexibility ◽  
Compact Size ◽  
Close Proximity ◽  
Cellular Communication Network ◽  
Arc Shape ◽  
Broadside Radiation

AbstractSmartdielectric resonator antenna (DRA) having beam control mechanism is anew area to be explored by antenna researchers. Proposed new geometry DRA has low loss, design flexibility, high efficiency, compact size and desired radiated beam control. Developing beam control in new geometry DRAs is investigated for the first time in this letter. Unique technique for beam control and beam width control is proposed using pit top and mount top DRA. Gain is controlled from 5.0 to 9.98 dBi and beam is controlled from ±30° to ±70° in broadside radiation pattern. U shape pit DRA has maximum directive gain of 9.98 dBi and efficiency 98% at 5.8 GHz frequency. Measured and simulated results of radiation pattern and reflection coefficient are found to be in close proximity. Hardware of U shape pit top DRA, mount top DRA, left side arc top DRA, right side arc shape top DRA is developed and investigated. Mobile and cellular communication network need wide coverage, hence large beam width is required. Narrowing of beam width at higher order mode is also achieved.

scholarly journals FEBID 3D-Nanoprinting at Low Substrate Temperatures: Pushing the Speed While Keeping the Quality

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1527
Author(s):  
Jakob Hinum-Wagner ◽  
David Kuhness ◽  
Gerald Kothleitner ◽  
Robert Winkler ◽  
Harald Plank
Keyword(s):  
Volume Growth ◽  
Point Of View ◽  
High Fidelity ◽  
Direct Write ◽  
General Picture ◽  
3D Space ◽  
Design Flexibility ◽  
Substrate Temperatures ◽  
Very High ◽  
Comprehensive Discussion

High-fidelity 3D printing of nanoscale objects is an increasing relevant but challenging task. Among the few fabrication techniques, focused electron beam induced deposition (FEBID) has demonstrated its high potential due to its direct-write character, nanoscale capabilities in 3D space and a very high design flexibility. A limitation, however, is the low fabrication speed, which often restricts 3D-FEBID for the fabrication of single objects. In this study, we approach that challenge by reducing the substrate temperatures with a homemade Peltier stage and investigate the effects on Pt based 3D deposits in a temperature range of 5–30 °C. The findings reveal a volume growth rate boost up to a factor of 5.6, while the shape fidelity in 3D space is maintained. From a materials point of view, the internal nanogranular composition is practically unaffected down to 10 °C, followed by a slight grain size increase for even lower temperatures. The study is complemented by a comprehensive discussion about the growth mechanism for a more general picture. The combined findings demonstrate that FEBID on low substrate temperatures is not only much faster, but practically free of drawbacks during high fidelity 3D nanofabrication.

Nanomechanical Biosensor Using Polymer Membranes

2004 ◽  
Author(s):  
Srinath Satyanarayana ◽  
Daniel T. McCormick ◽  
Arun Majumdar
Keyword(s):  
Surface Stress ◽  
A Priori ◽  
Detection Systems ◽  
Stress Sensors ◽  
Design Flexibility ◽  
High Elasticity ◽  
Sensor Geometry ◽  
Specific Reactions ◽  
Higher Sensitivity ◽  
Made In

In recent years several surface stress sensors based on microcantilevers have been developed for biosensing [1–4]. Since these sensors are made using standard microfabrication processes, they can be easily made in an array format, making them suitable for high-throughput multiplexed analysis. Specific reactions occurring on one surface (enabled by selective modification of the surface a priori) of the sensor element change the surface stress, which in turn causes the sensor to deflect. The magnitude and the rate of deflection are then used to study the reaction. The microcantilevers in these sensors are usually fabricated using material like silicon and its oxides or nitrides. The high elasticity modulus of these materials places limitations on the sensitivity and sensor geometry. Alternately polymers, which have a much lower elastic modulus when compared to silicon or its derivatives, offers greater design flexibility, i.e. allow the exploration of innovative sensor configurations that can have higher sensitivity and at the same time are suitable for integration with microfluidics and electrical detection systems.

Compliant Pantographs via the Pseudo-Rigid-Body Model

1998 ◽  
Author(s):  
Andrew J. Nielson ◽  
Larry L. Howell
Keyword(s):  
Rigid Body ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Test Results ◽  
Rigid Link ◽  
Body Model ◽  
Design Flexibility ◽  
Model Predictions ◽  
Rigid Body Model ◽  
Classical Mechanism

Abstract This paper uses a familiar classical mechanism, the pantograph, to demonstrate the utility of the pseudo-rigid-body model in the design of compliant mechanisms to replace rigid-link mechanisms, and to illustrate the advantages and limitations of the resulting compliant mechanisms. To demonstrate the increase in design flexibility, three different compliant mechanism configurations were developed for a single corresponding rigid-link mechanism. The rigid-link pantograph consisted of six links and seven joints, while the corresponding compliant mechanisms had no more than two links and three joints (a reduction of at least four links and four joints). A fourth compliant pantograph, corresponding to a rhomboid pantograph, was also designed and tested. The test results showed that the pseudo-rigid-body model predictions were accurate over a large range, and the mechanisms had displacement characteristics of rigid-link mechanisms in that range. The limitations of the compliant mechanisms included reduced range compared to their rigid-link counterparts. Also, the force-deflection characteristics were predicted by the pseudo-rigid-body model, but they did not resemble those for a rigid-link pantograph because of the energy storage in the flexible segments.

scholarly journals Transformation Thermodynamics with Arbitrarily Shaped Non-Conformal Objects and Coatings

2018 ◽  
Vol 186 ◽  
pp. 01007
Author(s):  
Qingxiang Ji ◽  
Guodong Fang ◽  
Jun Liang
Keyword(s):  
Thermal Protection ◽  
Small Region ◽  
Heat Fluxes ◽  
Temperature Fields ◽  
Heat Flows ◽  
Thermal Protection Systems ◽  
Thermal Fields ◽  
Design Flexibility ◽  
Protection Systems ◽  
Concentrate Heat

In this paper we apply transformation optics theory to thermodynamics and design thermal cloaks and concentrators with arbitrarily shaped non-conformal objects and coatings. Expressions of the required material parameters are derived analytically and then validated by numerical simulations. We apply this method to design a thermal cloak which can guide the heat flow around the inner domain without perturbation to external thermal fields. In this way, the object inside the inner domain is protected from the invasion of external heat fluxes. In contrast, a concentrator is designed to concentrate heat flows into a small region without disturbing outside temperature fields, which can considerably enhance the heat density in the designed domain. The proposed method extends the design flexibility in manipulating heat flux and will find wide applications in thermal protection systems, solar cells and so on.

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