scholarly journals Studies of Electron-Molecule Collisions on Distributed-memory Parallel Computers

1992 ◽  
Vol 45 (3) ◽  
pp. 325 ◽  
Author(s):  
Carl Winstead ◽  
Qiyan Sun ◽  
Paul G Hipes ◽  
Marco AP Lima ◽  
Vincent McKoy

We review recent progress in the study of low-energy collisions between electrons and polyatomic molecules which has resulted from the application of distributed-memory parallel computing to this challenging problem. Recent studies of electronically elastic and inelastic scattering from several molecular systems, including ethene, propene, cyclopropane, and disilane, are presented. We also discuss the potential of ab initio methods combined with cost-effective parallel computation to provide critical data for the modeling of materials-processing plasmas.

2005 ◽  
Vol 18 (2) ◽  
pp. 219-224
Author(s):  
Emina Milovanovic ◽  
Natalija Stojanovic

Because many universities lack the funds to purchase expensive parallel computers, cost effective alternatives are needed to teach students about parallel processing. Free software is available to support the three major paradigms of parallel computing. Parallaxis is a sophisticated SIMD simulator which runs on a variety of platforms.jBACI shared memory simulator supports the MIMD model of computing with a common shared memory. PVM and MPI allow students to treat a network of workstations as a message passing MIMD multicomputer with distributed memory. Each of this software tools can be used in a variety of courses to give students experience with parallel algorithms.


2021 ◽  
Vol 26 ◽  
pp. 1-67
Author(s):  
Patrick Dinklage ◽  
Jonas Ellert ◽  
Johannes Fischer ◽  
Florian Kurpicz ◽  
Marvin Löbel

We present new sequential and parallel algorithms for wavelet tree construction based on a new bottom-up technique. This technique makes use of the structure of the wavelet trees—refining the characters represented in a node of the tree with increasing depth—in an opposite way, by first computing the leaves (most refined), and then propagating this information upwards to the root of the tree. We first describe new sequential algorithms, both in RAM and external memory. Based on these results, we adapt these algorithms to parallel computers, where we address both shared memory and distributed memory settings. In practice, all our algorithms outperform previous ones in both time and memory efficiency, because we can compute all auxiliary information solely based on the information we obtained from computing the leaves. Most of our algorithms are also adapted to the wavelet matrix , a variant that is particularly suited for large alphabets.


1991 ◽  
Vol 237 ◽  
Author(s):  
Harry A. Atwater ◽  
C. J. Tsai ◽  
S. Nikzad ◽  
M.V.R. Murty

ABSTRACTRecent progress in low energy ion-surface interactions, and the early stages of ion-assisted epitaxy of semiconductor thin films is described. Advances in three areas are discussed: dynamics of displacements and defect incorporation, nucleation mechanisms, and the use of ion bombardment to modify epitaxial growth kinetics in atrulysurface-selective manner.


2000 ◽  
Vol 14 (15) ◽  
pp. 563-570 ◽  
Author(s):  
M. ZAKAULLAH ◽  
IJAZ AKHTAR ◽  
S. F. MEHMOOD ◽  
A. WAHEED ◽  
G. MURTAZA

A time-resolved rugged X-ray detector (XRD) which may be used in intense radiation environment is developed. The detector is used to study the X-ray emission from a low-energy (2.3 kJ) Mather-type plasma focus energized by a 32 μF single capacitor, using hydrogen and argon (3:2) mixture as gas filling. In the detector, the electron emitter is made of nickel and aluminum. The sensitivity of the detector with nickel cathode is found to be very low. No signal could be recorded by masking the detector with even the 2 μm thick Al foil. When Al cathode is used in the XRD, the sensitivity of the detector increases abruptly. To stop the optical/ultraviolet radiation from approaching the active area, it is masked with 6 μm Al filter. It is found that an XRD with nickel cathode is not useful for X-ray detection in a low-energy plasma focus. However, due to its excellent response to vacuum ultraviolet radiation (≤600 Å), it may find application in the study of the axial rundown of current sheath, and its velocity. The X-ray emission from focus plasma is the highest at 0.5 mbar. With increase in pressure, the emission is dropped. At filling pressures of 2.0–2.5 mbar, the X-ray emission increases again. High X-ray emission at 0.5 mbar is due to interaction of energetic electrons in the current sheath with the anode surface, whereas moderately high emission at 2.0–2.5 mbar is caused by an axially moving shockwave.


Author(s):  
Abdaoui Noura ◽  
Ismahène Hadj Khalifa ◽  
Sami Faiz

In the concept of internet of things (IOT), physical position of smart object is very useful for relevant function over sensor networks. However, the invalid information of indoor geo-localization systems relative to these wireless sensor compromises the intelligence of IOT network. Therefore, this chapter produces the recent progress in the indoor geo-localization systems and the IOTs area. It defines the best indoor geo-localization technologies that meet their needs while respecting the constraints related to sensor networks. This framework combines between simplicity of Bluetooth low energy (BLE), popular wi-fi infrastructure, and the k-nearest neighbor (KNN) algorithm (in order to filter the initial fingerprint dataset). This new conception increases real-time detection accuracy and guarantees the low energy consumption.


Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5721
Author(s):  
Sarah El Himer ◽  
Salima El Ayane ◽  
Sara El Yahyaoui ◽  
Jean Paul Salvestrini ◽  
Ali Ahaitouf

Concentrator Photovoltaic (CPV) technology, by using efficient optical elements, small sizes and high efficiency multi-junction solar cells, can be seen as a bright energy source to produce more cost-effective electricity. The main and basic idea is to replace the use of expensive solar cells with less expensive optical elements made from different materials. This paper aims to give to the readers a rapid and concise overview of CPV and the main characteristics to be considered when designing a CPV system. It reviews the main optical configurations presented in the literature, their advantages and drawbacks, as well as the recent progress in the concentration ratio and the major performances achieved in the field. The paper considers the more recent works, their optical designs, as well as their optical and electrical performances. It also relates the major achievements on the industrial side with the major milestones in CPV developments.


2020 ◽  
Vol 32 (35) ◽  
pp. 1907101 ◽  
Author(s):  
Woo‐Bin Jung ◽  
Sungwoo Jang ◽  
Soo‐Yeon Cho ◽  
Hwan‐Jin Jeon ◽  
Hee‐Tae Jung

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