Low-G Electrostatically Actuated Resonant Switch

2012 ◽  
Author(s):  
Abdallah Ramini ◽  
Mohammad I. Younis ◽  
Quang T. Su
Keyword(s):  
Experimental Data ◽  
Response Curves ◽  
Single Degree Of Freedom ◽  
Electrostatically Actuated ◽  
Single Degree ◽  
Earthquake Detection ◽  
Switching Action ◽  
Simulation Results ◽  
Resonant Switch ◽  
Good Agreement

This work investigates a new concept of an electrostatically actuated resonant switch (EARS) for earthquake detection and low-g seismic applications. The resonator is proposed to operate close to instability bands of frequency-response curves, where it is forced to pull-in if operated within these bands. By careful tuning, the resonator can be made to enter the instability zone upon the detection of the earthquake signal, thereby pulling-in as a switch. Such a switching action can be functionalized for alarming purposes or can be used to activate a network of sensors for seismic activity recording. The EARS is modeled and its dynamic response is simulated using a nonlinear single degree of freedom model. Experimental investigation is conducted demonstrating the EARS capability of being triggered at small levels of acceleration as low as 0.02 g. Experimental data and simulation results are compared showing good agreement.

Enhancing the Sensitivity of Electrostatically Actuated Resonant Switch for Earthquake Detection

2011 ◽  
Author(s):  
Abdallah H. Ramini ◽  
Mohammad I. Younis
Keyword(s):  
Printed Circuit Board ◽  
Degree Of Freedom ◽  
Circuit Board ◽  
Response Curves ◽  
Single Degree Of Freedom ◽  
Printed Circuit ◽  
Electrostatically Actuated ◽  
Earthquake Detection ◽  
Switching Action ◽  
Resonant Switch

Enhancing the sensitivity of an electrostatically actuated resonant switch (EARS) for earthquake detection is investigated. The resonator is proposed to operate close to instability bands of frequency-response curves, where it is forced to pull-in if operated within these bands. By careful tuning, the resonator can be made to enter the instability zone upon the detection of the earthquake signal, thereby pulling-in as a switch. Such a switching action can be functionalized for alarming purposes or can be used to activate a network of sensors for seismic activity recording. By placing such a resonator on a printed circuit board of a natural frequency close to that of the earthquake’s frequency, significant improvement on the detection limit of this switch is achieved. In this work, nonlinear Single-Degree-Of-Freedom (SDOF) and 2-Degree-Of-Freedom (2-DOF) models are used to simulate the performance of the switch concept.

The penetration and ricochet of ogive-nosed rigid projectiles obliquely impacting metallic targets

2021 ◽  
pp. 204141962110377
Author(s):  
Yaniv Vayig ◽  
Zvi Rosenberg
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Dynamic Pressure ◽  
Oblique Impacts ◽  
Simulation Results ◽  
The Impact ◽  
Penetration Depths ◽  
Resistance To Penetration ◽  
Good Agreement

A large number of 3D numerical simulations were performed in order to follow the trajectory changes of rigid CRH3 ogive-nosed projectiles, impacting semi-infinite metallic targets at various obliquities. These trajectory changes are shown to be related to the threshold ricochet angles of the projectile/target pairs. These threshold angles are the impact obliquities where the projectiles end up moving in a path parallel to the target’s face. They were found to depend on a non-dimensional entity which is equal to the ratio between the target’s resistance to penetration and the dynamic pressure exerted by the projectile upon impact. Good agreement was obtained by comparing simulation results for these trajectory changes with experimental data from several published works. In addition, numerically-based relations were derived for the penetration depths of these ogive-nosed projectiles at oblique impacts, which are shown to agree with the simulation results.

scholarly journals Orthogonal contrasts: definitions and concepts

2004 ◽  
Vol 61 (1) ◽  
pp. 118-124 ◽  
Author(s):  
Maria Cristina Stolf Nogueira
Keyword(s):  
Experimental Data ◽  
Statistical Analysis ◽  
Interaction Effects ◽  
Degree Of Freedom ◽  
Extensive Review ◽  
Single Degree Of Freedom ◽  
Orthogonal Contrasts ◽  
Single Degree ◽  
Definite Structure

The single degree of freedom of orthogonal contrasts is a useful technique for the analysis of experimental data and helpful in obtaining estimates of main, nested and interaction effects, for mean comparisons between groups of data and in obtaining specific residuals. Furthermore, the application of orthogonal contrasts is an alternative way of doing statistical analysis on data from non-conventional experiments, whithout a definite structure. To justify its application, an extensive review is made on the definitions and concepts involving contrasts.

New module for channeling radiation simulation in Geant4

2021 ◽  
Vol 16 (12) ◽  
pp. P12042
Author(s):  
A.A. Savchenko ◽  
W. Wagner
Keyword(s):  
Experimental Data ◽  
Single Crystals ◽  
Dipole Approximation ◽  
Relativistic Electrons ◽  
Planar Channeling ◽  
Classical Approach ◽  
Electrons And Positrons ◽  
Simulation Results ◽  
Channeling Radiation ◽  
Good Agreement

Abstract We present a new C++ module for simulation of channeling radiation to be implemented in Geant4 as a discrete physical process. The module allows simulation of channeling radiation from relativistic electrons and positrons with energies above 100 MeV for various types of single crystals. In this paper, we simulate planar channeling radiation applying the classical approach in the dipole approximation as a first attempt not yet considering other contributory processes. Simulation results are proved to be in a rather good agreement with experimental data.

THE CORRELATION BETWEEN BOND ANGLE DISTRIBUTION AND THE COORDINATION OF SILICA LIQUID UNDER PRESSURE

2012 ◽  
Vol 26 (20) ◽  
pp. 1250117 ◽  
Author(s):  
L. T. VINH ◽  
N. V. HUY ◽  
P. K. HUNG
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Bond Angle ◽  
Simple Expression ◽  
Dynamics Simulation ◽  
Angle Distribution ◽  
Bond Angle Distribution ◽  
Simulation Results ◽  
Substantial Change ◽  
Good Agreement

Molecular dynamics simulation is carried out for liquid SiO 2 at pressure ranged from zero to 30 GPa and by using BKS, Born–Mayer type and Morse–Stretch potentials. The constructed models reproduce well the experimental data in terms of mean coordination number, bond angle and pair radial distribution function. Furthermore, the density of all samples can be expressed by a linear function of fractions SiO x. It is found that the topology of units SiO x and linkages OSi y is unchanged upon compression although the liquid undergoes substantial change in its network structure. Consequently, the partial bond angle distribution for SiO x and OSi y is identical for all samples constructed by the same potential. This result allows to establishing a simple expression between total bond angle distribution (BAD) and fraction of SiO x and OSi y. The simulation shows a good agreement between the calculation and simulation results for both total O–Si–O and Si–O–Si BADs. This supports a technique to estimate amount of units SiO x and linkages OSi y on base of total Si–O–Si and O–Si–O BADs measured experimentally.

Simulation on Coal Devolatilization Combined a Multi-Step Kinetic Model with Chemkin Software

2012 ◽  
Vol 608-609 ◽  
pp. 1375-1382
Author(s):  
Rui Zhang ◽  
Qin Hui Wang ◽  
Zhong Yang Luo ◽  
Meng Xiang Fang
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Intermediate Product ◽  
Coal Combustion ◽  
Model Complexity ◽  
Coal Pyrolysis ◽  
Simple Application ◽  
Calculation Results ◽  
Simulation Results ◽  
Good Agreement

As the first step in coal combustion and gasification, coal devolatilization has significant effect on reaction process. Previous coal devolatilization models have some disadvantages, such as poor flexibility, model complexity, and requirement of characterization parameters. Recently, Sommariva et al. have proposed a multi-step kinetic model of coal devolatilization. This model avoids the disadvantages mentioned above and can predict elemental composition of tar and char. In this paper, the mechanism of this model has been revised for simple application to Chemkin. Revision method is that some reactions are split into more reactions by using one pseudo-intermediate-product to replace several final products. Simulation results show that calculation results from revised mechanism compare quite well with that from original mechanism and have good agreement with experimental data. The revised mechanism is accurate and can be applied to Chemkin very easily, which gives it wide application to simulation of coal pyrolysis, gasification and combustion.

scholarly journals Development of n-DoF Preloaded Structures for Impact Mitigation in Cobots

2018 ◽  
Vol 10 (5) ◽  
Author(s):  
S. Seriani ◽  
P. Gallina ◽  
L. Scalera ◽  
V. Lughi
Keyword(s):  
Three Dimensional ◽  
Impact Loads ◽  
Single Degree Of Freedom ◽  
Impact Mitigation ◽  
Single Degree ◽  
Future Developments ◽  
Core Issue ◽  
Comprehensive Framework ◽  
Peculiar Behavior ◽  
Good Agreement

A core issue in collaborative robotics is that of impact mitigation, especially when collisions happen with operators. Passively compliant structures can be used as the frame of the cobot, although, usually, they are implemented by means of a single-degree-of-freedom (DoF). However, n-DoF preloaded structures offer a number of advantages in terms of flexibility in designing their behavior. In this work, we propose a comprehensive framework for classifying n-DoF preloaded structures, including one-, two-, and three-dimensional arrays. Furthermore, we investigate the implications of the peculiar behavior of these structures—which present sharp stiff-to-compliant transitions at design-determined load thresholds—on impact mitigation. To this regard, an analytical n-DoF dynamic model was developed and numerically implemented. A prototype of a 10DoF structure was tested under static and impact loads, showing a very good agreement with the model. Future developments will see the application of n-DoF preloaded structures to impact-mitigation on cobots and in the field of mobile robots, as well as to the field of novel architected materials.

Characterization of effects of selected organic substances on decomposition of hydrogen peroxide during Fenton reaction

2004 ◽  
Vol 49 (4) ◽  
pp. 129-134 ◽  
Author(s):  
K.C. Namkung ◽  
A. Aris ◽  
P.N. Sharratt
Keyword(s):  
Experimental Data ◽  
Hydrogen Peroxide ◽  
Fenton Reaction ◽  
Reactive Black 5 ◽  
Organic Substances ◽  
Oxidation Model ◽  
Simulation Results ◽  
Good Agreement

This study aims to investigate the effects of selected organic substances on the degradation of hydrogen peroxide during the Fenton reaction. Since the presence of organic substances can strongly affect the mechanism of the Fenton reaction, the information on effects of organic substances on the reaction would be a vital guide to the success of its application to the destruction of organics in wastewater. Several organic compounds having different structures were selected as model pollutants: 4-chlorophenol, 1,4-dioxane, chloroform, a dye (reactive black-5), and EDTA. Oxidation of 4-chlorophenol and reactive black-5 resulted in enormously fast degradation of hydrogen peroxide, while others such as 1,4-dioxane and chloroform showed much slower degradation. These experimental data were compared to simulation results from a computational model based on a simple áOH-driven oxidation model. Modelling results for chloroform and 1,4-dioxane were in relatively good agreement with the experimental data, while those for 4-chlorophenol and reactive black-5 were very different from the experimental data. The results for EDTA showed a different trend to those for other compounds. From these results, classification of organic substances into several sub-groups was tried.

In-plane Thermal and Electronic Transport in Quantum Dot Superlattice

2001 ◽  
Vol 677 ◽  
Author(s):  
A. Khitun ◽  
J.L. Liu ◽  
K.L. Wang ◽  
G. Chen
Keyword(s):  
Experimental Data ◽  
Thermal Properties ◽  
Quantum Dot ◽  
Electronic Transport ◽  
Lattice Thermal Conductivity ◽  
Phonon Transport ◽  
Host Materials ◽  
Simulation Results ◽  
Germanium Quantum Dots ◽  
Good Agreement

ABSTRACTWe present a theoretical model in order to describe both thermal and electronic in-plane transports in quantum dot superlattice. The model takes into account the modifications of electron and phonon transport due to the space confinement caused by the mismatch in electronic and thermal properties between dot and host materials. The developed model provides the analysis of the in-plane superlattice electronic and thermal properties versus quantum dot size and their arrangement. Numerical calculations were carried out for a structure that consists of multiple layers of Si with regimented germanium quantum dots. The simulation results of the lattice thermal conductivity are in a good agreement with experimental data.

scholarly journals Blast Simulator Testing of Structures: Methodology and Validation

2011 ◽  
Vol 18 (4) ◽  
pp. 579-592 ◽  
Author(s):  
T. Rodriguez-Nikl ◽  
G.A. Hegemier ◽  
F. Seible
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Detailed Model ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Explosive Materials ◽  
Blast Effects ◽  
Resistance Function ◽  
The University ◽  
Good Agreement

The blast simulator at the University of California, San Diego is a unique tool for conducting full-scale testing of blast effects on structures without the use of explosive materials. This blast simulator uses high speed hydraulic actuators to launch specially designed modules toward the specimen, thereby imparting impulse in a blast-like manner. This method of testing offers numerous advantages over field tests with actual explosives, including cost, turn-around time, repeatability, and a clear view of the progression of damage in the specimen. The viability of this method is established by comparing results obtained in the blast simulator with results obtained with actual explosives. The process by which the impulse is imparted to the specimen is then described by a detailed model based on the equivalent single degree of freedom method. Impulse calculated by the model is found to be in good agreement with the experimentally recorded values. Calculated impulse is found to be relatively insensitive to assumptions made about the specimen's resistance function (often not well known before a test) implying that the model can be used with confidence in designing an experimental study.

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