Output Power Optimization of Energy Harvester, Employing Segmentation of Its Electrodes

This research suggests employing electrode segmentation in order to avoid charge cancellation in the piezoelectric layers of harvester, which occurs, if strain nodes of vibrating harvester are covered by continuous electrodes. For the experimental investigations two types of piezoelectric energy harvester prototypes were produced from piezoelectric T107 H4E 602 plate, epoxy bonded to stainless steel substrate. The first (reference) harvester prototype posses no electrode segmentation, while electrodes covering piezoelectric material of second harvester were segmented. Segmentation of the second harvester was configured for its operation at the second resonant frequency – i. e., performed so, that the electrodes of piezoelectric material are not covering strain node of the second vibration mode. Experimental results revealed that segmented harvester prototype posses efficiency advantage as compared to the non-segmented counterpart – adding voltages, generated at each segment would result from 8% to 52% increase of maximum generated voltage

Measurement of trajectories of piezoelectric actuators with laser

Various measurement techniques have been developed for analyzing performance of piezoelectric devices. Recently laser Doppler vibrometer (LDV) has become a widely applied instrument for vibration measurements both in scientific studies and industry. The most common type of LDV is a single-point vibrometer. In this article we propose a system consisting of the single-point LDV, beam deflector and mirrors, which enable automated 2D/3D trajectory or 2D vibration measurements, where a high number of target points can be measured with a very high spatial resolution. We used two test objects to demonstrate the performance of the system: piezo-actuator, which transforms vibrations to the rotational movement and a micrometric screw with piezo-adjustment

Piezoelectric actuator for high resolution linear displacement systems

This work presents a piezoelectric actuator which is designed to improve resolution for micrometer screws or motorized actuators such as actuators with stepper motors. Several modifications of piezoelectric actuator were implemented for closed-loop and open-loop applications. For closed-loop applications strain gages are used to obtain a feedback signal. As a result a resolution of displacement measurement up to 18 nm is achieve

Lambda Station: On-Demand Flow Based Routing for Data Intensive Grid Applications Over Multitopology Networks

Lambda Station is an ongoing project of Fermi National Accelerator Laboratory and the California Institute of Technology. The goal of this project is to design, develop and deploy network services for path selection, admission control and flow based forwarding of traffic among data-intensive Grid applications such as are used in High Energy Physics and other communities. Lambda Station deals with the last-mile problem in local area networks, connecting production clusters through a rich array of wide area networks. Selective forwarding of traffic is controlled dynamically at the demand of applications. This paper introduces the motivation of this project, design principles and current status. Integration of Lambda Station client API with the essential Grid middleware such as the dCache/SRM Storage Resource Manager is also described. Finally, the results of applying Lambda Station services to development and production clusters at Fermilab and Caltech over advanced networks such as DOE's UltraScience Net and NSF's UltraLight is covered

Lambda Station: On-Demand Flow Based Routing for Data Intensive Grid Applications Over Multitopology Networks

Lambda Station is an ongoing project of Fermi National Accelerator Laboratory and the California Institute of Technology. The goal of this project is to design, develop and deploy network services for path selection, admission control and flow based forwarding of traffic among data-intensive Grid applications such as are used in High Energy Physics and other communities. Lambda Station deals with the last-mile problem in local area networks, connecting production clusters through a rich array of wide area networks. Selective forwarding of traffic is controlled dynamically at the demand of applications. This paper introduces the motivation of this project, design principles and current status. Integration of Lambda Station client API with the essential Grid middleware such as the dCache/SRM Storage Resource Manager is also described. Finally, the results of applying Lambda Station services to development and production clusters at Fermilab and Caltech over advanced networks such as DOE's UltraScience Net and NSF's UltraLight is covered

Providing a computing environment for a high energy physics workshop

Although computing facilities have been provided at conferences and workshops remote from the host institution for some years, the equipment provided has rarely been capable of providing for much more than simple editing and electronic mail. This report documents the effort involved in providing a local computing facility with world-wide networking capability for a physics workshop so that we and others can benefit from the knowledge gained through the experience

Application of the Scanning Electron Microscopy in Soil Fine-Dispersive Fraction Investigations

Santr. liet. žrn. galeBibliogr.: p. 138 (7 pavad.)Vytauto Didžiojo universitetasŽemės ūkio akademij

Polyvinylpyrrolidone surface modification with SiOx containing amorphous hydrogenated carbon (a-C:H/SiOx) and nitrogen-doped a-C:H/SiOx films using Hall-type closed drift ion beam source

In this study SiOx containing amorphous hydrogenated carbon (a-C:H/SiOx) and nitrogen-doped a-C:H/SiOx (a-C:H:N/SiOx) films were deposited on polyvinylpyrrolidone (PVP) templates of variable thickness using a Hall-type closed drift ion beam source with constant irradiation parameters. A detailed surface characterization was followed using atomic force microscopy (AFM) topography images, surface morphology parameters, height distribution histograms and bearing ratio curves with hybrid parameters. The AFM analysis directly showed that the a-C:H/SiOx/PVP and a-C:H:N/SiOx/PVP composite films represent different morphologies with characteristic surface textures. Surface adhesive properties were evaluated by measuring the force required to separate the AFM tip from the surface by means of AFM force-distance curves. The variance in adhesion force detected was lower for a-C:H/SiOx/PVP composite films due to lower structural homogeneity of the surfaces. Fourier transform infrared spectroscopy analysis was performed to study the blend behavior of PVP upon a-C:H/SiOx and a-C:H:N/SiOx direct ion beam deposition. It was determined that interfacial interactions of PVP with the direct ion beam induced changes in the carbonyl group of the PVP and are dependent on the carrier gas used for the synthesis of the amorphous hydrogenated carbon films

Water droplet behavior on superhydrophobic SiO2 nanocomposite films during icing/deicing cycles

This work investigates water droplet behavior on superhydrophobic (water contact angle value of 162 ± 1°) SiO2 nanocomposite films subjected to repetitive icing/deicing treatments, changes in SiO2 nanocomposite film surface morphology and their non-wetting characteristics. During the experiment, water droplets on SiO2 nanocomposite film surface are subjected to a series of icing and deicing cycles in a humid (~ 70% relative humidity) atmosphere and the resulting morphological changes are monitored and characterized using atomic force microscopy (AFM) and contact angle measurements. Our data show that the formation of the frozen or thawed water droplet, with no further shape change, on superhydrophobic SiO2 nanocomposite film, is obtained faster within each cycle as the number of the icing/deicing cycles increases. After 10 icing and deicing cycles, the superhydrophobic SiO2 nanocomposite film had a water contact angle value of 146 ± 2° which is effectively non-superhydrophobic. AFM analysis showed that the superhydrophobic SiO2 nanocomposite film surface area under the water droplet undergoes gradual mechanical damage during the repetitive icing/deicing cycles. We propose a possible mechanism of the morphological changes to the film surface that take place during the consecutive icing/deicing experiments