Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

Advanced oxidation processes for in-situ production of hydrogen peroxide/hydroxyl radical for textile wastewater treatment: A review

Figure 1 . a) Optical image of a rollerball pen loaded with a conductive silver ink. The background shows conductive text written on Xerox paper. b and c) SEM images of the side and top views of the rollerball pen. d) Optical image of the rollerball pen tip, captured during writing a conductive silver track on a Xerox paper. Printed electronics constitute an emerging class of materials with potential application in photovoltaics, [ 1 ] transistors, [ 2 , 3 ] displays, [ 4–6 ] batteries, [ 7 ] antennas, [ 8 ] and sensors. [ 9 , 10 ] Recent attention has focused on paper substrates as a low-cost, enabling platform for fl exible, lightweight, and disposable devices. [ 11–13 ]

Pen‐on‐Paper Flexible Electronics

The area of artificial muscle is a highly interdisciplinary field of research that has evolved rapidly in the last 30 years. Recent advances in nanomaterial fabrication and characterization, specifically carbon nanotubes and nanowires, have had major contributions in the development of artificial muscles. However, what can artificial muscles really do for humans? This question is considered here by first examining nature's solutions to this design problem and then discussing the structure, actuation mechanism, applications, and limitations of recently developed artificial muscles, including highly oriented semicrystalline polymer fibers; nanocomposite actuators; twisted nanofiber yarns; thermally activated shape-memory alloys; ionic-polymer/metal composites; dielectric-elastomer actuators; conducting polymers; stimuli-responsive gels; piezoelectric, electrostrictive, magnetostrictive, and photostrictive actuators; photoexcited actuators; electrostatic actuators; and pneumatic actuators.

Artificial Muscles: Mechanisms, Applications, and Challenges.

This review covers energy harvesting technologies associated with pyroelectric materials and systems. Such materials have the potential to generate electrical power from thermal fluctuations and is a less well explored form of thermal energy harvesting than thermoelectric systems. The pyroelectric effect and potential thermal and electric field cycles for energy harvesting are explored. Materials of interest are discussed and pyroelectric architectures and systems that can be employed to improve device performance, such as frequency and power level, are described. In addition to the solid materials employed, the appropriate pyroelectric harvesting circuits to condition and store the electrical power are discussed.

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Pyroelectric materials and devices for energy harvesting applications

An analytical approach to the static, dynamic, and stability analysis of the microstructures subjected to electrostatic forces is presented in this paper. The present model has the advantages of full analytical description, explicit physical meanings, and agrees well with the reality under small deflection. The stiffness of a microstructure will be softened periodically with the frequency of applied voltage and the variation increases with increasing the magnitude of applied voltage. The dynamic instabilities may occur below the pull-in voltage. The instable regions appear not only near the multiples of resonant frequencies but also near some fractions of resonant frequency differences. Furthermore, the instable regions expand with increasing the applied voltage.

Some design considerations on the electrostatically actuated microstructures

Electrostatic-driven microelectromechanical systems devices, in most cases, consist of couplings of such energy domains as electromechanics, optical electricity, thermoelectricity, and electromagnetism. Their nonlinear working state makes their analysis complex and complicated. This article introduces the physical model of pull-in voltage, dynamic characteristic analysis, air damping effect, reliability, numerical modeling method, and application of electrostatic-driven MEMS devices.

https://www.mdpi.com/1424-8220/10/6/6149/pdf

Review on the Modeling of Electrostatic MEMS

Novel biometric flow slab design for improvement of PEMFC performance

A flexible proximity sensor fully fabricated by inkjet printing is proposed in this paper. The flexible proximity sensor is composed of a ZnO layer sandwiched in between a flexible aluminum sheet and a web-shaped top electrode layer. The flexible aluminum sheet serves as the bottom electrode. The material of the top electrode layer is nano silver. Both the ZnO and top electrode layers are deposited by inkjet printing. The fully inkjet printing process possesses the advantages of direct patterning and low-cost. It does not require photolithography and etching processes since the pattern is directly printed on the flexible aluminum sheet. The prototype demonstrates that the presented flexible sensor is sensitive to the human body. It may be applied to proximity sensing or thermal eradiation sensing.

https://www.mdpi.com/1424-8220/10/5/5054/pdf

A Flexible Proximity Sensor Fully Fabricated by Inkjet Printing

This paper derives three analytical models, namely the full-order, the fourth-order and the third-order models, and the corresponding closed form solutions for the pull-in voltages of micro curled beams subjected to electrostatic loads. The analytical models are derived based on the Euler–Bernoulli beam theory and Taylor's series expansion and are then solved by the energy method. The accuracy of the present models is verified through comparing with former analytical models and the experimentally measured data conducted in former works. It is verified that the present closed form solutions are more accurate than past works. This paper also compares three commonly used assumed deflection shape functions and shows that the natural mode of the beam is the best choice in predicting the pull-in voltage. The present closed form solutions for the pull-in voltage are very convenient and accurate enough for implementation in device design.

Yuh-Chung Hu

Papers

Some design considerations on the electrostatically actuated microstructures

Review on the Modeling of Electrostatic MEMS

Novel biometric flow slab design for improvement of PEMFC performance

A Flexible Proximity Sensor Fully Fabricated by Inkjet Printing

Closed form solutions for the pull-in voltage of micro curled beams subjected to electrostatic loads