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22,237 full-text articles. Page 634 of 634.

Solar Energy Entrepreneurship: Today’S Challenges, Tomorrow’S Opportunities, Siva Reddy V, ranjan k. R, kaushik S.C, Panwar NL 2009 IIT Delhi

Solar Energy Entrepreneurship: Today’S Challenges, Tomorrow’S Opportunities, Siva Reddy V, Ranjan K. R, Kaushik S.C, Panwar Nl

Dr. V. Siva Reddy

Renewable energy sources are sustainable and have the potential to meet present and future global energy demands without inflicting any environmental impacts. The use of renewable energy sources through solar energy systems not only saves the precious high grade energy, but also decreases the rate of depletion of fossil fuels. It also improves the nations (world) economy as investment in the solar energy technologies may cost less than efforts to fulfill the increased demand of fuel supply in future including the cost of damaging factors of environment. One of the promising options is proved to be Solar Energy. It has ...


A Tangent-Plane, Marker-Particle Method For The Computation Of Three-Dimensional Solid Surfaces Evolving By Surface Diffusion On A Substrate, Ping Du, Mikhail Khenner, Harris Wong 2009 Western Kentucky University

A Tangent-Plane, Marker-Particle Method For The Computation Of Three-Dimensional Solid Surfaces Evolving By Surface Diffusion On A Substrate, Ping Du, Mikhail Khenner, Harris Wong

Mikhail Khenner

We introduce a marker-particle method for the computation of three-dimensional solid surface morphologies evolving by surface diffusion. The method does not use gridding of surfaces or numerical differentiation, and applies to surfaces with finite slopes and overhangs. We demonstrate the method by computing the evolution of perturbed cylindrical wires on a substrate. We show that computed growth rates at early times agree with those predicted by the linear stability analysis. Furthermore, when the marker particles are redistributed periodically to maintain even spacing, the method can follow breakup of the wire.


Oscillatory And Monotonic Modes Of Long-Wave Marangoni Convection In A Thin Film, Sergey Shklyaev, Mikhail Khenner, Alexei Alabuzhev 2009 Western Kentucky University

Oscillatory And Monotonic Modes Of Long-Wave Marangoni Convection In A Thin Film, Sergey Shklyaev, Mikhail Khenner, Alexei Alabuzhev

Mikhail Khenner

We study long-wave Marangoni convection in a layer heated from below. Using the scaling k=O#1;#3;Bi#2;, where k is the wave number and Bi is the Biot number, we derive a set of amplitude equations. Analysis of this set shows presence of monotonic and oscillatory modes of instability. Oscillatory mode has not been previously found for such direction of heating. Studies of weakly nonlinear dynamics demonstrate that stable steady and oscillatory patterns can be found near the stability threshold.


Thickness-Dependent Spontaneous Dewetting Morphology Of Ultrathin Ag Films, H Krishna, R Sachan, J Strader, C Favazza, Mikhail Khenner, Ramki Kalyanaraman 2009 Washington University in St Louis

Thickness-Dependent Spontaneous Dewetting Morphology Of Ultrathin Ag Films, H Krishna, R Sachan, J Strader, C Favazza, Mikhail Khenner, Ramki Kalyanaraman

Mikhail Khenner

We show here that the morphological pathway of spontaneous dewetting of ultrathin Ag films on SiO2 under nanosecond laser melting is found to be film thickness dependent. For films with thickness h between 2<=h<=9.5 nm, the intermediate stages of the morphology consisted of bicontinuous structures. For films 11.5<=h<=20 nm, the intermediate stages consisted of regularly-sized holes. Measurement of the characteristic length scales for different stages of dewetting as a function of film thickness showed a systematic increase, which is consistent with the spinodal dewetting instability over the entire thickness range investigated. This change in morphology with thickness is consistent with observations made previously for polymer films [A. Shama et al, Phys. Rev. Lett., v81, pp3463 (1998); R. Seemann et al, J. Phys. Cond. Matt., v13, pp4925, (2001)]. Based on the behavior of free energy curvature that incorporates intermolecular forces, we have estimated the morphological transition thickness for Ag on SiO2. The theory predictions agree well with observations for Ag. These results show that it is possible to form a variety of complex Ag nanomorphologies in a consistent manner, which could be useful in optical applications of Ag surfaces, such as in surface enhanced Raman sensing.


Super-High-Frequency Two-Port Aln Contour-Mode Resonators For Rf Applications, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza 2009 University of Pennsylvania

Super-High-Frequency Two-Port Aln Contour-Mode Resonators For Rf Applications, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza

Matteo Rinaldi

This paper reports on the design and experimental verification of a new class of thin-film (250 nm) super-high-frequency laterally-vibrating piezoelectric microelectromechanical (MEMS) resonators suitable for the fabrication of narrow-band MEMS filters operating at frequencies above 3 GHz. The device dimensions have been opportunely scaled both in the lateral and vertical dimensions to excite a contour-extensional mode of vibration in nanofeatures of an ultra-thin (250 nm) AlN film. In this first demonstration, 2-port resonators vibrating up to 4.5 GHz have been fabricated on the same die and attained electromechanical coupling, kt2, in excess of 1.5%. These devices are employed ...


Demonstration Of Low Voltage And Functionally Complete Logic Operations Using Body-Biased Complementary And Ultra-Thin Aln Piezoelectric Mechanical Switches, Nipun Sinha, Timothy S. Jones, Zhijun Guo, Gianluca Piazza 2009 University of Pennsylvania

Demonstration Of Low Voltage And Functionally Complete Logic Operations Using Body-Biased Complementary And Ultra-Thin Aln Piezoelectric Mechanical Switches, Nipun Sinha, Timothy S. Jones, Zhijun Guo, Gianluca Piazza

Nipun Sinha

This paper reports, for the first time, on the demonstration of low voltage and functionally complete logic elements (NAND and NOR) implemented by using body-biased complementary and ultra-thin (250 nm thick) Aluminum Nitride (AlN) based piezoelectric mechanical switches. This work presents, firstly, the importance of scaling AlN films for the demonstration of ultra-thin AlN switches and, secondly, the implementation of a new actuation scheme based on body biasing to lower the switch threshold voltage. Four of these ultra-thin switches were connected together to synthesize functionally complete MEMS logic gates (NAND and NOR) with a ± 2V swing and a body-bias voltage < 8 V.


Pricing Residential Water To Account For Scarcity In Cyprus, Theodoros Zachariadis 2009 Cyprus University of Technology

Pricing Residential Water To Account For Scarcity In Cyprus, Theodoros Zachariadis

Theodoros Zachariadis

No abstract provided.


Preliminary Numerical Analysis Of Valve Fatigue In A Checkball Pump For Driveline Applicatio, Yang Yang 2009 Western Michigan University

Preliminary Numerical Analysis Of Valve Fatigue In A Checkball Pump For Driveline Applicatio, Yang Yang

Yang Yang

Recent studies have shown that hydraulic hybrid drivelines can significantly improve fuel savings for medium weight vehicles on stop-start drivecycles. In a series hydraulic hybrid (SHH) architecture, the conventional mechanical driveline is replaced with a hydraulic driveline that decouples vehicle speed from engine speed. In an effort to increase the design space, this paper explores the use of a fixed displacement check-ball piston pump in an SHH driveline. This paper identifies the potential life-limiting components of a fixed-displacement checkball piston pump and examines the likelihood of surface fatigue in the check valves themselves. Numerical analysis in ABAQUS software suggests that ...


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