scholarly journals Investigation of the Effect of Spin Crossover on the Static and Dynamic Properties of MEMS Microcantilevers Coated with Nanocomposite Films of [Fe(Htrz)2(trz)](BF4)@P(VDF-TrFE)

2021 ◽  
Vol 7 (8) ◽  
pp. 114
Author(s):  
José Elías Angulo-Cervera ◽  
Mario Piedrahita-Bello ◽  
Fabrice Mathieu ◽  
Thierry Leichle ◽  
Liviu Nicu ◽  
...  
Keyword(s):  
Dynamic Properties ◽  
Spin Transition ◽  
Spray Coating ◽  
Thermomechanical Properties ◽  
Nanocomposite Films ◽  
Resonance Frequencies ◽  
Nanocomposite Thin Films ◽  
Out Of Plane ◽  
Flexural Analysis ◽  
Actuation Strain

We used a spray-coating process to cover silicon microcantilevers with ca. 33 wt% [Fe(Htrz)2(trz)](BF4)@P(VDF70-TrFE30) nanocomposite thin films of 1500 nm thickness. The bilayer cantilevers were then used to investigate the thermomechanical properties of the composites through a combined static and dynamic flexural analysis. The out-of-plane flexural resonance frequencies were used to assess the Young’s modulus of the spray-coated films (3.2 GPa). Then, the quasi-static flexural bending data allowed us to extract the actuation strain (1.3%) and an actuation stress (7.7 MPa) associated with the spin transition in the composite.

scholarly journals Designing of Drive Systems in the Aspect of the Desired Spectrum of Operation

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2562
Author(s):  
Tomasz Dzitkowski ◽  
Andrzej Dymarek ◽  
Jerzy Margielewicz ◽  
Damian Gąska ◽  
Lukasz Orzech ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Dynamic Parameters ◽  
Synthesis Algorithm ◽  
Moments Of Inertia ◽  
Driving System ◽  
Six Degrees Of Freedom ◽  
Resonance Frequencies ◽  
Drive Systems ◽  
Power Component

A method for selecting dynamic parameters and structures of drive systems using the synthesis algorithm is presented. The dynamic parameters of the system with six degrees of freedom, consisting of a power component (motor) and a two-speed gearbox, were determined, based on a formalized methodology. The required gearbox is to work in specific resonance zones, i.e., meet the required dynamic properties such as the required resonance frequencies. In the result of the tests, a series of parameters of the drive system, defining the required dynamic properties such as the resonance and anti-resonance frequencies were recorded. Mass moments of inertia of the wheels and elastic components, contained in the required structure of the driving system, were determined for the selected parameters obtained during the synthesis.

Enhanced electrical conductivity of Au–LaNiO3 nanocomposite thin films by chemical solution deposition

RSC Advances ◽  
2015 ◽  
Vol 5 (94) ◽  
pp. 76783-76787 ◽  
Author(s):  
H. L. Wang ◽  
X. K. Ning ◽  
Z. J. Wang
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Electrical Properties ◽  
Chemical Solution Deposition ◽  
Nanocomposite Films ◽  
Chemical Solution ◽  
Solution Deposition ◽  
Nanocomposite Thin Films ◽  
One Step

Au–LaNiO3 (Au–LNO) nanocomposite films with 3.84 at% Au were firstly fabricated by one-step chemical solution deposition (CSD), and their electrical properties were investigated.

scholarly journals The Effect of Working Gases Mixing Ratios on the Synthesis and Characteristics of TiO2/SiO2 Nanocomposite via Closed-Field unbalanced DC Magnetron Co-Sputtering Technique

2021 ◽  
Vol 2114 (1) ◽  
pp. 012060
Author(s):  
N. H. Mutesher
Keyword(s):  
Optical Properties ◽  
Nanocomposite Films ◽  
Closed Field ◽  
Mixing Ratio ◽  
X Ray Diffraction ◽  
Energy Band Gap ◽  
Structural And Optical Properties ◽  
Mixing Ratios ◽  
Deposition Parameters ◽  
Nanocomposite Thin Films

Abstract The objective of this research is to study the influence of deposition parameters such as gases mixing ratio O2/Ar on the structural and optical properties of the TiO2/SiO2 nanocomposite films synthesized using closed field unbalanced dc magnetron co-sputtering technique. The nanocomposite thin films were characterized using x-ray diffraction (XRD) to determine the phase structure, and Fourier transform infrared (FTIR) spectroscopy to investigate Si-O-Si, Ti-O and Si–O–Ti. functional groups. The UV-VIS. absorption spectra of the synthesized films reveal that the indirect energy band gap was found to be 2.75 eV. The mixing ratio of Oxygen and Argon (O2/Ar) gases has a pronounced controlling effect on the structural and optical properties of such nanocomposite.

scholarly journals Effect of Grain Refinement on the Dynamic, Mechanical Properties, and Corrosion Behaviour of Al-Mg Alloy

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1825
Author(s):  
Haitham M. Ahmed ◽  
Hussin A. M. Ahmed ◽  
Mohammed Hefni ◽  
Essam B. Moustafa
Keyword(s):  
Mechanical Properties ◽  
Grain Refinement ◽  
Corrosion Behaviour ◽  
Cast Alloy ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Xrd Analysis ◽  
Optical Microscope ◽  
Mg Alloy ◽  
Resonance Frequencies

In this investigation, aluminium Al-2.5% Mg cast alloy was modified by adding 0.5 Ti and 0.1 B wt % modifiers to investigate their impact on the dynamic behaviour, as well as the mechanical and microstructure properties. The dynamic properties were analysed experimentally using a free vibration impact test and predicted using finite element methods. This study used a high-resolution polarised optical microscope to analyse the microstructure of the studied alloys and X-ray Powder Diffraction (XRD) analysis to determine the developed phases. Microstructure and mechanical properties were mostly enhanced as a result of grain refining during solidification and through the metal segregation process. The microstructure analysis of the modified alloy showed a significant improvement in the grain refinement; hence, the grains were 10 times finer than the cast alloy. The modified Al-2.5% Mg/Ti-B alloy demonstrated reduced inter-granular corrosion (IGC) than the Al-2.5% Mg standard cast alloy. By incorporating Ti-B modifiers into the composition of the cast Al-Mg alloy, the ultimate tensile strength (UTS), strain (ε), and hardness values (HV) were increased by 30.5%, 100%, and 18.18%, respectively. The dynamic properties of the modified alloy showed an enhancement in the resonant (fn) and damping ratio (ζ) by 7% and 68%, respectively. The predicted resonance frequencies of the investigated alloys showed results close to the experimental dynamic tests.

TEMPERATURE EFFECT ON THERMOMECHANICAL PROPERTIES OF BERYLLIUM CHALCOGENIDES BeS, BeSe AND BeTe

2006 ◽  
Vol 20 (01) ◽  
pp. 49-61 ◽  
Author(s):  
F. BENKABOU
Keyword(s):  
Elastic Constants ◽  
Dynamic Properties ◽  
Theoretical Calculations ◽  
Thermomechanical Properties ◽  
Structural Dynamic ◽  
Experimental Values ◽  
Beryllium Chalcogenides ◽  
Increasing Temperature ◽  
And Diffusion ◽  
Good Agreement

We have used the molecular-dynamic method for the calculation of the structural, dynamic and elastic properties of group BeS , BeSe and BeTe compounds for temperature ranging from 300 to 1200 K. Tersoff potential has been used to model the interaction between the groups II–VI compound atoms. The structural properties of cubic BeS , BeSe and BeTe have been calculated, and good agreement between the calculated and experimental values have been found. We have also predicted the elastic constants and diffusion coefficients of BeS , BeSe and BeTe . The values found compare very well with the theoretical results. For the temperature range under study, all elastic constants and dynamic properties show a softening with increasing temperature very similar to the theoretical calculations.

Nanoparticle Reinforced Metal Composites Prepared by Electrocodeposition

2013 ◽  
Author(s):  
Michael J. Koludrovich ◽  
Yong X. Gan
Keyword(s):  
Thin Films ◽  
Nanocomposite Films ◽  
Alumina Nanoparticles ◽  
Al2o3 Nanoparticles ◽  
Nanoparticle Agglomeration ◽  
Control Film ◽  
Significant Difference ◽  
Nanocomposite Thin Films ◽  
Agglomeration Of Nanoparticles ◽  
Pure Cu

Improving the physical and mechanical properties such as hardness and strength of metal thin films can be achieved by incorporating nanoparticles into the pure metals, for example via electrocodeposition. However, the agglomeration of nanoparticles during electrocodeposition of nanocomposite thin films is an unresolved issue. This paper presents the preliminary results of electrocodeposition thin nanocomposite films under different processing conditions. The microstructure and distribution of Al2O3 nanoparticles in electrocodeposited Cu matrix nanocomposite thin films on a pure Al plate were examined. In addition, the effect of electrolyte concentration on the agglomeration of nanoparticles was studied. Different stirring times were used for electrodepositing the alumina/Cu nanocomposite and the pure Cu control film. Under the constant stirring condition, different deposition times including 1, 4, 8, 12, and 24 hours were taken to study the differences between the agglomeration states of the alumina nanoparticles with the time change. We also examined the effect of turning the electromagnetic stirrer ON and OFF at different time intervals from as short as every 20 minutes to as long as ON and OFF every 2 hours on the nanoparticle agglomeration in the film. Optical and electron microscopic studies were made to reveal the microstructure of the nanocomposite. It is found that there is no significant difference in microstructures for the specimens that made under either intermittent stirring or constant stirring for the same length of time.

Dynamic Characteristics of Tsing Ma Suspension Bridge

1996 ◽  
Vol 1541 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Siu Kui Au ◽  
Neil Mickleborough ◽  
Paul N. Roschke
Keyword(s):  
Analytical Solutions ◽  
Bridge Deck ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
Suspension Bridge ◽  
Mode Shapes ◽  
Out Of Plane ◽  
Quantitative Results ◽  
Suspension Cable ◽  
Bending Modes

Numerical simulation was carried out to determine the dynamic properties of the Tsing Ma Suspension Bridge. Both the structure as a whole and individual subcomponents were modeled. Classical analytical solutions for simplified models from the available literature were compared with the results obtained from a finite-element code. Quantitative results for static deflection, natural frequencies, and mode shapes were compared with analytical solutions from linear theory. Out-of-plane modes were shown to be dominant. For in-plane antisymmetric and symmetric bending modes, in which the suspension cable and bridge deck vibrate in the same direction, the natural frequency of the main span of the bridge is determined to be approximately equal to the square root of the sum of the squares of the frequencies of the cable and bridge deck.

Optical Properties of Ag Nanoparticles Embedded Ba0.5Sr0.5TiO3 Films Prepared by Alternating Pulsed Laser Deposition

2006 ◽  
Vol 6 (11) ◽  
pp. 3426-3428
Author(s):  
Ji-Suk Kim ◽  
Kyeong-Seok Lee ◽  
Sang Sub Kim
Keyword(s):  
Pulsed Laser Deposition ◽  
Volume Fraction ◽  
Pulsed Laser ◽  
Fused Silica ◽  
Laser Deposition ◽  
Nanocomposite Films ◽  
Nonlinear Susceptibility ◽  
Third Order ◽  
Ag Particles ◽  
Nanocomposite Thin Films

Nanocomposite thin films consisting of nanometer-sized Ag particles embedded in amorphous Ba0.5Sr0.5TiO3 matrix were prepared on fused silica substrates by an alternating pulsed laser deposition method. Their optical nonlinearities have been studied using the Z-scan method. The surface plasmon resonance (SPR) peak shifts to red and increases with the increasing the volume fraction of Ag in the nanocomposite films. The magnitude of the third-order nonlinear susceptibility of the nanocomposite with an Ag volume fraction of 3.3% was calculated to be ∼2 × 10−8 esu at the SPR wavelength.

Impact Test in Working Space of Milling Center

2012 ◽  
Vol 463-464 ◽  
pp. 81-84
Author(s):  
Doina Marin ◽  
Nicolae Predincea ◽  
Dan Mihail Marin
Keyword(s):  
Impact Test ◽  
Dynamic Properties ◽  
Work Piece ◽  
Technical Problems ◽  
Working Space ◽  
Resonance Frequencies ◽  
Excited Vibration ◽  
Comparative Results ◽  
Clamping Device ◽  
Impulse Force

Experimental modal analysis is quickly developed area of science in last years. Experimental approach for solving technical problems is a means to estimate or evaluate modal properties of a mechanical structure. The paper is focused at dynamic properties of milling centers, namely at the resonance frequencies and vibration shapes of a simplified tool-work piece system. All this properties are identified by measurements. The machine tool vibration was excited by impulse force and a response of excited vibration was recorded. The measurement points for vibration were selected at the spindle head, the table and the clamping device. The paper aims to present comparative results of theoretical studies with experimental results obtained from impact test to the machining centers.

scholarly journals An overview on the seismic microzonation and site effect studies in Central Asia

2015 ◽  
Vol 58 (1) ◽  
Author(s):  
Marco Pilz ◽  
Tanatkan Abakanov ◽  
Kanatbek Abdrakhmatov ◽  
Dino Bindi ◽  
Tobias Boxberger ◽  
...  
Keyword(s):  
Central Asia ◽  
Seismic Noise ◽  
Dynamic Properties ◽  
Site Response ◽  
Site Effect ◽  
Seismic Zonation ◽  
Progressive Development ◽  
Array Measurements ◽  
Resonance Frequencies ◽  
Seismic Networks

<p>During the past centuries, many cities in Central Asia have suffered significant damages caused by earthquakes. A crucial step towards preparedness for future events, the definition of the optimal engineering designs for civil structures and the mitigation of earthquake risks involves the accomplishment of site response studies. To accurately identify local variations of the site response at different locations within the cities, earthquakes recorded by seismic networks as well as measurements of the seismic noise can be used for estimating the resonance frequencies and for evaluating the expected level of ground motion at each site. Additionally, the measurements can help identifying site specific features like more-dimensional resonances and directional effects. This information can be complemented with array measurements of ambient seismic noise in order to estimate local shear-wave velocity profiles, an essential parameter for evaluating the dynamic properties of soil, and to characterize the corresponding sediment layers at each site. The present study gives an overview on the progressive development of the seismic zonation studies in the frame of EMCA carried out in several cities in Central Asia.</p>

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