Efficient distributed simulation through dynamic load balancing

With recent advances in parallel computation, distributed simulation has become a viable way of dealing with time-consuming simulations. For distributed simulations to run efficiently, care must be taken in assigning the tasks (work) in the simulated system to the available physical processors in the computer system. An inefficient assignment can result in excessive communication times between processors and unfavorable load conditions. This leads to long run times, possibly giving performance worse than that with a uniprocessor sequential event-list implementation. This paper establishes the feasibility, and in some cases the necessity, of using dynamic task allocation (rather than a-priori static allocation) in distributed simulation. A dynamic reallocation strategy is developed, and experiments on an iPSC/2 Hypercube indicate that significant improvements in run time can be achieved at low cost.     

Properties of pulse electrodeposited copper indium selenide films

Copper Indium Selenide films were deposited by the pulse plating technique at different bath temperatures in the range of 30–80 °C and at 50 % duty cycle (15 s ON and 15 s OFF). X-ray diffraction studies indicated the formation of single phase chalcopyrite copper indium selenide films. The band gap of the films decreased from 1.17 to 1.05 eV with decrease of duty cycle. Atomic force microscope studies indicated that the surface roughness and grain size increased with duty cycle. Room temperature resistivity of the films is in the range of 0.01–2.0 ohm cm. Films deposited at 50 % duty cycle have exhibited a V_oc of 0.59 V, J_sc of 15 mA cm^?2, FF of 0.75 and efficiency of 6.64 %.     

Precision Nanocluster-Based Toroidal and Supertoroidal Frameworks Using Photocycloaddition-Assisted Dynamic Covalent Chemistry

Atomically precise nanoclusters (NCs) have recently emerged as ideal building blocks for constructing self-assembled multifunctional superstructures. The existing structures are based on various non-covalent interactions of the ligands on the NC surface, resulting in inter-NC interactions. Despite recent demonstrations on light-induced reversible self-assembly, long-range reversible self-assembly based on dynamic covalent chemistry on the NC surface has yet to be investigated. Here, it is shown that Au₂₅ NCs containing thiolated umbelliferone (7-hydroxycoumarin) ligands allow [2+2] photocycloaddition reaction-induced self-assembly into colloidal-level toroids. The toroids upon further irradiation undergo inter-toroidal reaction resulting in macroscopic supertoroidal honey-comb frameworks. Systematic investigation using electron microscopy, atomic force microscopy (AFM), and electron tomography (ET) suggest that the NCs initially form spherical aggregates. The spherical structures further undergo fusion resulting in toroid formation. Finally, the toroids fuse into macroscopic honeycomb frameworks. As a proof-of-concept, a cross-photocycloaddition reaction between coumarin-tethered NCs and an anticancer drug (5-fluorouracil) is demonstrated as a model photo-controlled drug release system. The model system allows systematic loading and unloading of the drug during the assembly and disassembly under two different wavelengths. The results suggest that the dynamic covalent chemistry on the NC surface offers a facile route for hierarchical multifunctional frameworks and photocontrolled drug release.     

Dynamics of Brownian motion and flux conditions on naturally unsteady thermophoretic flow with variable fluid properties

This work examines the boundary flow difficulties of the past and the heat transfer properties of Blasius and Sakiadis flows under prescribed concentration flux and prescribed heat flux. The nanofluid is also taken into account in this model, along with impacts from Brownian motion and thermophoresis. The modified system governing partial differential equations is numerically solved by using the R-K method along with the shooting technique. Various values of physical quantities like thermophoresis parameter, Brownian motion parameter, Eckert number, thermal radiation parameter, heat source parameter, and magnetic field parameter along with the $C_f,N{u}_x,\text{and}S{h}_x$ were calculated using the temperature, concentration, and velocity profiles. Finally, we demonstrated how the Brownian motion, radiation, and thermophoresis parameters can significantly increase the temperature distributions. The concentration distributions were decelerated with an increase in Brownian motion parameters for both Blasius and Sakiadis cases.     

Photopatternable High-k Polysilsesquioxane Dielectrics for Organic Integrated Devices: Effects of UV Curing on Chemical and Electrical Properties

Polysilsesquioxanes (PSQs) have generated great interest as solution-processable inorganic polymers for obtaining high-dielectric-constant (k) dielectrics. Engineering the side chains in PSQs can enhance the polarization characteristics and provide different functionalities, such as photopatternability and ferroelectric performance. In this study, two types of UV curable high-k PSQs are prepared by introducing epoxy-containing side chains to the PSQs: 1) glycidyl epoxy-containing linear groups and 2) bulky cycloaliphatic epoxy-containing groups. The physical, chemical, and electrical properties of these two materials after UV curing are investigated. Both PSQ films show high dielectric strength and are successfully patterned after exposure to UV light. The structure of the side chains influences the UV curing behavior and capacitance characteristics of the PSQ dielectrics. These differences determine the driving behavior of the fabricated organic thin-film transistors, which exhibits either stable or ferroelectric operation. Finally, logic gates and memory cells exhibiting low-voltage and non-destructive operations are successfully integrated using UV cured PSQs. This approach for engineering PSQs with the purpose of achieving desirable photopatternability and high dielectric or ferroelectric performance can be used to realize simple and inexpensive solution-processing techniques for next generation integrated electronics.     

Omicron: Understanding the Latest Variant of SARS-CoV-2 and Strategies for Tackling the Infection

The new variant of concern of SARS-CoV-2, namely Omicron, has triggered global fear recently. To date, our knowledge of Omicron, particularly of how S glycoprotein mutations affect the infectivity of the virus and the severity of the infection, is far from complete. This hinders our ability to treat the disease and to predict the future state of SARS-CoV-2 threats to well-being and economic stability. Despite this, efforts have been made to unveil the routes of transmission and the efficiency of existing vaccines in tackling Omicron. This article reviews the latest understanding of Omicron and the current status of the use of vaccines and drugs for infection control. It is hoped that this article can offer insights into the development of more effective measures to tackle the pandemic.