Ahmad I.,Bahauddin Zakariya University |
Ahmad M.,Bahauddin Zakariya University |
Ali I.,Bahauddin Zakariya University |
Kanwal M.,Bahauddin Zakariya University |
And 3 more authors.
Journal of Electronic Materials | Year: 2015
A series of Gd-substituted Ba-Co-based (M-type) hexaferrites having the chemical compositions of Ba0.5Co0.5GdxFe12−xO19 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) were prepared by co-precipitation method. The pellets formed by co-precipitated powder were calcined at a temperature of 1200°C for 20 h. Final sintering was done at 1320°C for 4 h. From the x-ray diffraction analysis, it was revealed that all the samples showed M-type hexagonal structure as a major phase. The scanning electron microscope was used to examine the morphology of the sintered ferrites. The average grain size estimated by the line intercept method was found to be in the range of 2.8–1.0 μm. The room temperature DC resistivity increases with increasing Gd-contents to make these ferrites useful for high frequency applications and microwave devices. Lower values of coercivity (Hc) and higher saturation magnetization (Ms) may be suitable to enhance the permeability of these ferrites, which is favorable for impedance matching in microwave absorption. In addition, reflection coefficients for a sample was also measured from a frequency of 1 MHz to 3 GHz and a reflection peak was observed at about 2.2 GHz. © 2015, The Minerals, Metals & Materials Society.
News Article | December 28, 2016
Reproducibility is a necessity for science but has often eluded researchers studying the lifetime of organic light-emitting diodes (OLEDs). Recent research from Japan sheds new light on why: impurities present in the vacuum chamber during fabrication but in amounts so small that they are easily overlooked. Organic light-emitting diodes use a stack of organic layers to convert electricity into light, and these organic layers are most commonly fabricated by heating source materials in vacuum to evaporate and deposit them onto a lower temperature substrate. While issues affecting the efficiency of OLEDs are already well understood, a complete picture of exactly how and why OLEDs degrade and lose brightness over time is still missing. Complicating matters is that devices fabricated with seemingly the same procedures and conditions but by different research groups often degrade at vastly different rates even when the initial performance is the same. Unable to attribute these reproducibility issues to known sources such as the amount of residual water in the chamber and the purity of the starting materials, a report published online in Scientific Reports on December 13, 2016, adds a new piece to the puzzle by focusing on the analysis of the environment in the vacuum chamber. "Although we often idealize vacuums as being clean environments, we detected many impurities floating in the vacuum even when the deposition chamber is at room temperature," says lead author Hiroshi Fujimoto, chief researcher at Fukuoka i3-Center for Organic Photonics and Electronics Research (i3-OPERA) and visiting associate professor of Kyushu University. Because of these impurities in the deposition chamber, the researchers found that the time until an OLED under operation dims by a given amount because of degradation, known as the lifetime, sharply increased for OLEDs that spent a shorter time in the deposition chamber during fabrication. This trend remained even after considering changes in residual water and source material purity, indicating the importance of controlling and minimizing the device fabrication time, a rarely discussed parameter. Research partners at Sumika Chemical Analysis Service Ltd. (SCAS) confirmed an increase of accumulated impurities with time by analyzing the materials that deposited on extremely clean silicon wafers that were stored in the deposition chamber when OLED materials were not being evaporated. Using a technique called liquid chromatography-mass spectrometry, the researchers found that many of the impurities could be traced to previously deposited materials and plasticizers from the vacuum chamber components. "Really small amounts of these impurities get incorporated into the fabricated devices and are causing large changes in the lifetime," says Professor Chihaya Adachi, director of Kyushu University's Center for Organic Photonics and Electronics Research (OPERA), which also took part in the study. In fact, the new results suggest that the impurities amount to less than even a single molecular layer. To improve lifetime reproducibility, a practice often adopted in industry is the use of dedicated deposition chambers for specific materials, but this can be difficult in academic labs, where often only a limited number of deposition systems are available for testing a wide variety of new materials. In these cases, deposition chamber design and cleaning in addition to control of the deposition time are especially important. "This is an excellent reminder of just how careful we need to be to do good, reproducible science," comments Professor Adachi. For more information, see "Influence of vacuum chamber impurities on the lifetime of organic light-emitting diodes," Scientific Reports 6, 38482 (2016); doi: 10.1038/srep38482. This work was performed by research groups at Kyushu University's Center for Organic Photonics and Electronics Research (OPERA), the Fukuoka i3-Center for Organic Photonics and Electronics Research (i3-OPERA), and the Institute of System, Information Technology and Nanotechnology (ISIT) in cooperation with Sumika Chemical Analysis Service Ltd. (SCAS). This research is ongoing in part under the Adachi Molecular Exciton Engineering Project funded by the Exploratory Research for Advanced Technology (ERATO) program of the Japan Science and Technology Agency (JST).
News Article | September 30, 2016
Hamburg and Schleswig-Holstein have achieved Germany’s renewable target for 2025. They already obtain 40% of their energy from renewables on an annual basis. A technological breakthrough, the digitization of industry, will be required to go further. This region of 4.5 million people expects to obtain 70% of its energy from renewables by 2025 and 100% by 2035. Schleswig-Holstein and Hamburg will be modelling the fourth industrial revolution. According to the booklet NEW 4.0, Northern German Energy Transition: NEW 4.0« is a unique project initiative in Hamburg and Schleswig-Holstein combining the forces of business, science and politics.”NEW” stands for the Norddeutsche Energie- Wende (Northern German Energy Transition) and »4.0« refers to the brink of the fourth industrial revolution: the digitisation of industry resulting from the smart networking of systems, an increasingly important component in the energy transition. As a large-scale transnational project, the aim of NEW 4.0 is to achieve a sustainable energy supply and thereby ensure the future viability of the region. More than 50 partners from the region are combining all necessary competencies and solution potentials to accelerate the energy transition in Northern Germany. This is very good news for a world concerned about climate change. Unlike North America, which is a long way from reaching the 1990 emissions benchmark set by the Kyoto Accord, Germany’s emissions are already 20% below 1990 levels. NEW 4.0 is expected to reduce the region’s CO2 emissions by another 50 to 70%. Hamburg Marketing GmbH points to already existing examples of this energy transition on a small scale: “In the automated Container Terminal Altenwerder (CTA) in Hamburg, battery-powered heavy goods vehicles transport containers between ships and storage yards. An intelligent software control system ensures that the removable batteries of these self-propelled vehicles are charged whenever there are high supplies of wind power available from the north German electricity grid. This guarantees efficient and eco-friendly operations of the container terminal. At the same time, this lighthouse project helps relieve the grid systems, which are strained by fluctuating power input from renewable energy sources. “Only a few kilometres away from the bustling CTA there is further proof of the energy transition’s progress: the Energy Bunker Wilhelmsburg, a former WW2 flak bunker, has been transformed into a green energy power plant. As part of the Renewable Wilhelmsburg climate protection scheme, the bunker supplies a local heating network with over 3,000 residential units with renewable thermal energy, while at the same time feeding green electricity for around 1,000 households into the power grid. In the future, the Energy Bunker will also be used to convert excess wind electricity into heat.” According to Dr Werner Beba, head of the Competence Centre for Renewable Energies and Energy Efficiency (CC4E) at the HAW Hamburg, NEW 4.0 will build upon these existing projects. “As part of the overall venture we will be coordinating a total of 101 individual projects. The partners of our Innovation Alliance will be developing projects aimed at improving flexibility, load transfer and storage. For example, with power-to-heat plants we are able to convert electricity into heat and feed it into Hamburg’s district heating grid. Battery storage facilities are already existent on a smaller scale on the wind farms. Now we are planning to connect larger areas to electrical energy storage systems. The novelty of our venture lies in merging all these components via communication and network technologies and operating it under the roof of one overall system, which is yet unprecedented.” About 60 regional and trans-regional partners have formed an “innovation alliance” to make NEW 4.0 possible. “With Trimet, Aurubis and ArcelorMittal we have Hamburg’s three largest energy- consuming enterprises on board of the project. Together, they consume about 25 percent of Hamburg’s electricity demands, which amounts to 12 billion kilowatt hours annually. As “load management flexibility partners,” industrial companies will play an important role in the project. By analysing the relevant production processes, we may be able to use surplus electricity whenever it is accrued in the grid. Optimised load management holds considerable potential for the successful implementation of the energy transition. Such synchronisation of production and consumption is one of the core tasks on the way to innovating the energy system,” explained Dr Baba. The partnership includes grid operators like TenneT, HanseWerk, Stromnetz Hamburg, and Schleswig-Holstein Netz. There are also “energy suppliers such as Hamburg Energie and Vattenfall, several public utilities such as Stadtwerke Norderstedt, Glückstadt and Flensburg, and technological companies such as Siemens and HanseWerk Natur.” Scientific input is coming from Fraunhofer, ISIT (Institute for Silicon Technology)Itzehoe, CC4E of the HAW Hamburg, the Hamburg University of Technology (TUHH), the University of Hamburg, the Helmut-Schmidt University, the universities of applied sciences FH Lübeck, FH Kiel and FH Flensburg, and the Hamburg Institute of International Economics. This alliance will invest around €90 million over the next four years. The Federal Ministry for Economic Affairs and Energy will put in another EUR 44 million. Photo credits: Container terminal / wind turbines at Hamburg by Christian Spahrbier courtesy www.mediaserver.hamburg.de; Windkraft Region Grabau/ wind energy – Photo: www.mediaserver.hamburg.de / imagefoto.de; Container ship on the Elbe Photo: www.mediaserver.hamburg.de / Andreas Vallbracht; Container terminal with wind turbine – Photo: www.mediaserver.hamburg.de / Ottmar Heinze Buy a cool T-shirt or mug in the CleanTechnica store! Keep up to date with all the hottest cleantech news by subscribing to our (free) cleantech daily newsletter or weekly newsletter, or keep an eye on sector-specific news by getting our (also free) solar energy newsletter, electric vehicle newsletter, or wind energy newsletter.
Belhedi A.,CEA Saclay Nuclear Research Center |
Belhedi A.,National Engineering School of Tunis |
Bourgeois S.,CEA Saclay Nuclear Research Center |
Gay-Bellile V.,CEA Saclay Nuclear Research Center |
And 3 more authors.
Proceedings - International Conference on Image Processing, ICIP | Year: 2012
Time-of-Flight (TOF) cameras measure, in real-time, the distance between the camera and objects in the scene. This opens new perspectives in different application fields: 3D reconstruction, Augmented Reality, video-surveillance, etc. However, like any sensor, TOF cameras have limitations related to their technology. One of them is distance distortion. In this paper, we present a new depth calibration method (estimation of distance distortion) for TOF cameras. Our approach has several advantages. First, it is based on a non-parametric model, contrary to most of the other methods. Second, it models under the same formalism the distortion variation according to the distance and the pixel position in the image. This improves calibration accuracy even at the image boundaries which are typically more distorted than the image center. A comparison with two state of the art parametric methods is presented. © 2012 IEEE.
Razaq A.,COMSATS Institute of Information Technology |
Khan A.A.,COMSATS Institute of Information Technology |
Asif M.H.,COMSATS Institute of Information Technology |
Iqbal S.,COMSATS Institute of Information Technology |
And 3 more authors.
Modern Physics Letters B | Year: 2015
Naturally, existing lignocelluloses fibers showed outstanding potential in paper industry and other conventional applications. On the other hand, lignocellulose fibers are suitable candidate for high-tech applications under the scope of abundance, flexibility, light-weight and environment friendliness. In this study, paper sheets were prepared from lignocelluloses fibers extracted from self-growing plant, typha angustifolia. Lignocelluloses paper sheets were characterized for scanning electron microscopy (SEM), universal testing machine (UTM) and vector network analyzer (VNA). Flexible paper sheets displayed a tensile strength of 9.1 MPa and further used as a substrate in patch antenna to observe dielectric characteristics. The patch antenna is designed at 5.1 GHz which showed return loss less than -10 dB and dielectric constant 3.71. The use of lignocelluloses paper sheet as a substrate in patch antenna will provide the opportunity of miniaturization of size and weight in comparison of a jean substrate based antenna. © 2015 World Scientific Publishing Company.
Razaq A.,COMSATS Institute of Information Technology |
Asif M.H.,COMSATS Institute of Information Technology |
Kalsoom R.,COMSATS Institute of Information Technology |
Khan A.F.,COMSATS Institute of Information Technology |
And 3 more authors.
Journal of Applied Polymer Science | Year: 2015
Direct use of lignocelluloses fibers as substrate for fabrication of conductive, electroactive, biodegradable, and low-cost electrode materials are in demand for high-tech applications of ion-exchange and energy storage devices. This article presents the preparation and characterizations of conductive and electroactive lignocelluloses-polyaniline (cellulose/PANI) composite paper. Lignocelluloses fibers were directly collected from the stem of self-growing plant, Typha Angusitfolia, and subsequently coated with the conductive and electroactive layer of PANI through chemical synthesis. Individual PANI-coated lignocelluloses fibers were converted into sheet and further characterized with Scanning Electron Microscopy, Fourier Transform Infrared, Thermogravimetric Analysis, electronic conductivity, and Cyclic Voltammetry. Cellulose/PANI composite paper revealed superior thermal characteristics and used as a working electrode in three different electrolytes for ion-exchange properties. Conductive composite paper (CCP) showed the charge storage capacity of ∼52 C/g at scan rate of 5 mV/s in 2M HCl solution. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42293. © 2015 Wiley Periodicals, Inc.
Soga T.,ISIT |
Soga T.,Japan Science and Technology Agency |
Sasaki H.,Kyushu University |
Hirao T.,Kyushu University |
And 3 more authors.
20th Asia and South Pacific Design Automation Conference, ASP-DAC 2015 | Year: 2015
This paper proposes a new hardware barrier mechanism which offers the flexibility to select which cores should join the synchronization, allowing for executing multiple multi-threaded applications by dividing a many-core processor into several groups. Experimental results based on an RTL simulation show that our hardware barrier achieves a 66-fold reduction in latency over typical software based implementations, with a hardware overhead of the processor of only 1.8%. Additionally, we demonstrate that the proposed mechanism is sufficiently flexible to cover a variety of core groups with minimal hardware overhead. © 2015 IEEE.
Sarwar M.N.,ISIT |
Awan M.S.,ISIT |
International Journal of Materials Research | Year: 2014
Polycrystalline zirconium nitride films (560 nm) were deposited on stainless steel (SS-316) substrates using the multi- target cathodic arc sputtering technique. Deposition was carried out under N2 reactive atmosphere (4 × 10-3 mbar) at two different temperatures, 150 and 200 8C. X-ray diffraction studies show that reflections from planes changed from (111) to (200) for deposition temperatures of 150 8C and 200 8C, respectively. Films deposited at 150 8C and 200 8C bear a critical load of 6.4 N and 6.8 N respectively, showing better adherence at higher temperature. This may be the result of film-substrate diffusion at the interface. © Carl Hanser Verlag GmbH & Co. KG.
Morimoto Y.,ISIT |
ACM SIGGRAPH 2012 Posters, SIGGRAPH'12 | Year: 2012
Simplified illustrations are effective for medical purposes in ways: they can quickly convey stories to patients, and avoid unnecessary graphic depiction. Despite their simplicity, such illustrations are not trivial to improvise. In this talk, we propose a new system that automatically transforms medical images into friendly 2D illustrations via an optimization problem. © 2012 ACM.
Ramadasan D.,CNRS Pascal Institute |
Chevaldonne M.,ISIT |
Chateau T.,CNRS Pascal Institute
2015 IEEE Virtual Reality Conference, VR 2015 - Proceedings | Year: 2015
This paper presents a new approach for multi-objects tracking from a video camera moving in an unknown environment. The tracking involves static objects of different known shapes, whose poses and sizes are determined online. For augmented reality applications, objects must be precisely tracked even if they are far from the camera or if they are hidden. Camera poses are computed using simultaneous localization and mapping (SLAM) based on bundle adjustment process to optimize problem parameters. We propose to include in an incremental bundle adjustment the parameters of the observed objects as well as the camera poses and 3D points. We show, through the example of 3D models of basics shapes (planes, parallelepipeds, cylinders and spheres) coarsely initialized online using a manual selection, that the joint optimization of parameters constrains the 3D points to approach the objects, and also constrains the objects to fit the 3D points. Moreover, we developed a generic and optimized library to solve this modified bundle adjustment and demonstrate the high performance of our solution compared to the state of the art alternative. Augmented reality experiments in realtime demonstrate the accuracy and the robustness of our method. © 2015 IEEE.